Display of three-dimensional objects

Abstract

Methods, devices, and systems are provided for displaying three-dimensional objects by individually diffracting light of different colors. In one aspect, an optical diffractive device includes a first diffractive element, a second diffractive element, and a color-selective polarizer therebetween. The first diffractive element is configured to diffract light of a first color in a first polarization state incident at a first angle of incidence with a first diffraction efficiency at a first diffraction angle and to diffract light of a second color in a second polarization state with a diffraction efficiency substantially less than the first diffraction efficiency. The polarizer is configured to rotate a second polarization state of the second color light to the first polarization state. The second diffractive element is configured to diffract light of the second color in the first polarization state with a second diffraction efficiency at a second diffraction angle substantially equal to the first diffraction angle.

Description

[Technical Field]

[0001] Reference This application claims priority to USSN 63 / 079,707, filed on 17 September 2020, entitled “DISPLAYING THREE-DIMENSIONAL OBJECTS,” and USSN 63 / 149,964, filed on 16 February 2021, entitled “RECONSTRUCTING OBJECTS WITH DISPLAY ZERO ORDER LIGHT SUPPRESSION,” the entire contents of which are incorporated herein by reference.

[0002] This disclosure relates to a three-dimensional (3D) display, and more specifically, to a 3D display involving object reconstruction. [Background technology]

[0003] Advances in conventional two-dimensional (2D) projection and 3D rendering have given rise to new approaches to 3D displays, including numerous hybrid technologies that combine head tracking and eye tracking with conventional display devices for virtual reality (VR), augmented reality (AR), and mixed reality (MR). These technologies, combined with tracking and measurement-based computation, attempt to recreate the experience of holographic images and simulate the stereo or intra-eye light field that can be represented by actual holograms. [Overview of the project]

[0004] This disclosure describes methods, apparatus, devices, and systems for reconstructing objects (e.g., 2D or 3D), particularly with display zero-order light suppression. This disclosure provides techniques that can efficiently suppress display zero-order light (e.g., reflected, diffracted, or transmitted) from the display in the reconstructed holographic scene (or holographic content) to improve the effect of the holographic scene and, therefore, the performance of the display system. As an example, when light is shone on a display for holographic reconstruction, a portion of the light is modulated by the hologram and incident on the display elements that form the desired holographic scene, and is diffracted by the display elements. The other portion of the light is incident on the gaps between the display elements on the display and is reflected by the gaps. The other reflected portion of the light can be considered at least a portion (e.g., major order) of display zero-order light that may be presented in an undesirable manner in the holographic scene. Display zero-order light can also include any other unwanted light from the display, e.g., light diffracted in the gaps, reflected light from the display elements, or reflected light from the display cover on the display. Embodiments of this disclosure can suppress such display zero-order light.

[0005] In some implementations, the hologram is configured such that a first portion of light irradiated onto a display element of the display is diffracted by the display element modulated by the hologram and has at least one characteristic different from the zero-order display light, which includes reflected light from the display. The zero-order display light may include a second portion of light irradiated onto the gap between the display elements and reflected by the gap, without modulation of the hologram. The technique can utilize the difference between the diffracted first portion of light and the zero-order display light (e.g., the reflected second portion of light) to suppress the zero-order display light in the holographic scene formed by the diffracted first portion of light. The technique can be applied individually or in combination thereof. The technique can be applied to any other display system that suppresses or removes undesirable light from desired light.

[0006] In some examples, displays are configured to suppress higher-order zero-order display light, for example, by including irregular or non-uniform display elements having different sizes. The display elements are non-periodic and can form a Voronoi pattern. In some examples, in a holographic scene, zero-order display light can have a much lower power density than the first diffracted portion of light. That is, zero-order display light is suppressed by increasing the signal-to-noise ratio of the holographic scene, for example by causing the zero-order display light to diverge without the divergence of the first diffracted portion of light, or by adjusting the phase of each display element within a predetermined phase range such as [0, 2π], or both. In some examples, zero-order display light is suppressed by directing the zero-order display light away from the first diffracted portion of light, for example by illuminating the display at an incident angle and pre-configuring a hologram such that the first diffracted portion of light still propagates around the vertical axis and the zero-order display light propagates at the reflection angle. Display zero-order light can be redirected by adding, for example, an additional optical diffraction grating structure to the outside of the holographic scene formed by the first diffracted portion of the light, thereby directing the display zero-order light further away from the holographic scene. Display zero-order light can be reflected backward away from the holographic scene. Display zero-order light can also be absorbed in front of the holographic scene.

[0007] In this disclosure, the terms "zero order" and "zero-order" are used interchangeably, and the terms "first order" and "first-order" are used interchangeably.

[0008] In this disclosure, the terms "zero order" and "zero-order" are used interchangeably, and the terms "first order" and "first-order" are used interchangeably.

[0009] One aspect of the present disclosure is characterized by irradiating a display with light, wherein a first portion of the light irradiates the display elements of the display, modulates the display elements of the display with a hologram corresponding to holographic data, i) diffracting the first portion of the light to form a holographic scene corresponding to the holographic data, and ii) suppressing zero-order display light in the holographic scene, wherein the zero-order display light includes reflected light from the display.

[0010] In some examples, illuminating a display with light includes a second portion of the light illuminating the gap between adjacent display elements. The zero-order display light may include at least one of the second portion of light reflected by the display gap, the second portion of light diffracted by the display gap, reflected light from the display elements, or reflected light from the display cover that surrounds the display.

[0011] The reflected light from the display can be configured to form primary zero-order display light and suppress one or more higher-order zero-order display light, and the display elements can be irregular or non-uniform. In some examples, the display elements form a Voronoi pattern.

[0012] In some implementations, the method further includes configuring a hologram such that the first diffracted portion of the light has at least one property distinct from the zero-order light of the display. The at least one property may include at least one of power density, beam divergence, propagation direction away from the display, or polarization state.

[0013] In some implementations, zero-order display light is suppressed in the holographic scene by a light suppression efficiency. Light suppression efficiency is defined as 1 minus the ratio of the amount of zero-order display light in the suppressed holographic scene to the amount of zero-order display light in the unsuppressed holographic scene. In some cases, the light suppression efficiency exceeds a predetermined percentage, which is one of 50%, 60%, 70%, 80%, 90%, or 99%. In some cases, the light suppression efficiency is 100%.

[0014] In some implementations, the method further includes determining the EM field contribution to each of the display elements of a display by calculating the electromagnetic (EM) field propagation from the primitive to the display element in a global three-dimensional (3D) coordinate system for each of the multiple primitives corresponding to the object, and for each of the display elements, generating the sum of the EM field contributions from the multiple primitives to the display element. Holographic data may include the sum of the EM field contributions from the multiple primitives of the object to the display elements of the display. Holographic scenes may include reconstructed objects corresponding to the object.

[0015] In some implementations, the holographic data includes the phase of each display element of the display, and the method further includes constructing a hologram by adjusting the phase of each display element to have a predetermined phase range. The predetermined phase range can be [0, 2π].

[0016] In some implementations, adjusting the phase of each display element is possible.

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[0017] In some implementations, adjusting each phase involves adjusting constants A and B so that the light suppression efficiency of the holographic scene is maximized. The light suppression efficiency may be greater than 50%, 60%, 70%, 80%, 90%, or 99%. In some cases, adjusting constants A and B involves adjusting constants A and B by a machine vision algorithm or a machine learning algorithm.

[0018] In some implementations, the method further includes diverging a first diffracted portion of light to form a holographic scene, and diverging display zero-order light in or adjacent to the holographic scene. In some examples, diverging a first diffracted portion of light includes guiding the first diffracted portion of light to pass through an optical divergent component located downstream of the display, and diverging display zero-order light includes guiding the display zero-order light to pass through an optical divergent component.

[0019] In some examples, the light illuminating the display is collimated light. The zero-order light of the display is collimated before it reaches the optically divergent components, and the method may further configure the hologram such that the diffracted first portion of the light converges before it reaches the optically divergent components.

[0020] In some implementations, the holographic data includes the respective phase for each of the display elements. The method may further include constructing a hologram by adding a corresponding phase to each of the display elements, the corresponding phase for each display element may be compensated by an optical divergent component such that the holographic scene corresponds to the respective phase of each display element. The corresponding phase for each of the display elements is,

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[0021] In some implementations, the holographic scene corresponds to a reconstructed cone having a field of view. The method may further include: moving a constituent cone relative to a global 3D coordinate system, relative to the display, along a direction perpendicular to the display, by a distance corresponding to the focal length of an optically divergent component, such that the constituent cone corresponds to a reconstructed cone and has the same apex angle as the field of view; and generating holographic data based on the moved constituent cone in the global 3D coordinate system. Multiple primitives of an object may be located within the moved constituent cone.

[0022] In some implementations, the optical divergence component is a defocusing element that includes at least one of a concave lens or a holographic optical element (HOE) configured to diffract the zeroth-order light of the display outside the holographic scene.

[0023] In some implementations, the optical divergence component is, The focusing element includes at least one convex lens or holographic optical element (HOE) configured to diffract the zeroth-order light of the display outside the holographic scene.

[0024] In some implementations, the method further includes displaying a holographic scene on a two-dimensional (2D) screen spaced away from the display along a direction perpendicular to the display. The method may further include moving the 2D screen to obtain different slices of the holographic scene on the 2D screen.

[0025] In some implementations, the method further includes inducing light to illuminate a display. In some examples, inducing light to illuminate a display includes inducing light by a beam splitter, and the diffracted first portion of the light and the zeroth-order light of the display are transmitted through the beam splitter.

[0026] In some implementations, illuminating a display with light includes illuminating the display with light perpendicularly incident to it.

[0027] In some implementations, the first diffracted portion of light forms a reconstructed cone with a viewing angle, and illuminating the display with light includes illuminating the display with light at an incident angle greater than half of the viewing angle. In some examples, the method further includes configuring the hologram such that the first diffracted portion of light forms the same reconstructed cone as the reconstructed cone formed by the first diffracted portion of light when light is normally incident on the display.

[0028] In some examples, the holographic data includes the respective phase for each display element. The method may further include constructing a hologram by adding a corresponding phase to each of the display elements, the corresponding phase for each display element may be compensated for by the angle of incidence so that the holographic scene corresponds to the respective phase of the display element.

[0029] In some examples, the corresponding phase for each display element is:

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[0030] In some examples, constructing a hologram involves moving a constructing cone relative to a display in a global 3D coordinate system, wherein the constructing cone corresponds to a reconstructed cone and has an apex angle corresponding to the viewing angle of the reconstructed cone, and generating holographic data based on the moved constructing cone in the global 3D coordinate system.

[0031] In some examples, moving a cone relative to a display in a global 3D coordinate system includes rotating the cone relative to the surface of the display in a global 3D coordinate system by an angle of rotation, where the angle of rotation corresponds to the angle of incidence.

[0032] In some implementations, the method further includes blocking the zeroth-order light of the display from appearing in the holographic scene. The light suppression efficiency of the holographic scene may be 100%. In some examples, blocking the zeroth-order light of the display includes guiding the zeroth-order light of the display toward an optically blocked element located downstream of the display. The method may further include guiding a first portion of the light diffracted to transmit through the optically blocked element with a transmission efficiency to form the holographic scene. The transmission efficiency may not be less than a predetermined ratio. The predetermined ratio may be 50%, 60%, 70%, 80%, 90%, or 99%.

[0033] In some implementations, the optical blocking component is configured to transmit a first light beam having an angle smaller than a predetermined angle and to block a second light beam having an angle larger than a predetermined angle, where the predetermined angle is smaller than the angle of incidence and greater than half of the field of view. The optical blocking component may include a plurality of microstructures or nanostructures, metamaterial layers, or optically anisotropic films.

[0034] In some implementations, the method further includes guiding light to illuminate a display by guiding light to pass through an optical diffraction component on a substrate configured to diffract light at an angle of incidence. Guiding light to illuminate a display may include guiding light to the optical diffraction component through a waveguide coupler, guiding light to the optical diffraction component through a coupling prism, or guiding light to the optical diffraction component through a wedge-shaped surface of the substrate.

[0035] In some implementations, the optical diffraction component is formed on a first surface of the substrate facing the display, and the optical shielding component is formed on a second surface of the substrate opposite to the first surface.

[0036] In some implementations, the method further includes redirecting the display's zero-order light away from the holographic scene. The light suppression efficiency of the holographic scene can be 100%.

[0037] In some implementations, redirecting the display zero-order light away from the holographic scene involves diffracting the display zero-order light away from the holographic scene using an optical redirection component located downstream of the display. The optical redirection component can be configured to transmit a first diffracted portion of the light to form the holographic scene.

[0038] In some implementations, the optical redirection component is configured such that the zero-order light of the display is diffracted outwards in three-dimensional (3D) space along at least one of the following directions: upward, downward, leftward, rightward, or a combination thereof.

[0039] In some implementations, the optical redirection component is configured to diffract a first light beam having the same angle as a predetermined angle with substantially greater diffraction efficiency than a second light beam having a different angle, where the predetermined angle is substantially the same as the angle of incidence. The optical redirection component may include a Bragg grating.

[0040] In some implementations, the optical diffraction component is formed on a first surface of the substrate facing the display, and the optical redirection component is formed on a second surface of the substrate opposite to the first surface.

[0041] In some cases, the angle of incidence of light is negative, and the diffraction angle of the zero-order display light diffracted by the optical redirection component is negative. In some cases, the angle of incidence of light is positive, and the diffraction angle of the zero-order display light diffracted by the optical redirection component is positive. In some cases, the angle of incidence of light is negative, and the diffraction angle of the zero-order display light diffracted by the optical redirection component is positive. In some cases, the angle of incidence of light is positive, and the diffraction angle of the zero-order display light diffracted by the optical redirection component is negative.

[0042] In some implementations, the optical redirection component is covered by a second substrate. The method further includes absorbing the zero-order display light that is redirected by the optical redirection component and reflected by the interface between the second substrate and the surrounding medium, by a light absorber formed on the side of the second substrate or on at least one of the side of the substrate.

[0043] In some implementations, the second substrate includes an anti-reflective coating on the surface of the second substrate opposite to the optical redirection component, and the anti-reflective coating is configured to transmit zero-order light of the display.

[0044] In some implementations, the zero-order display light is p-polarized before arriving at the second substrate, and the optical redirection component is configured to diffract the zero-order display light so that it is completely transmitted through the second substrate and incident at a Brewster angle at the interface between the second substrate and the surrounding medium.

[0045] In some implementations, the method further includes converting the polarization state of the display zero-order light from s-polarization to p-polarization before the display zero-order light reaches the second substrate. In some cases, converting the polarization state of the display zero-order light includes converting the polarization state of the display zero-order light by an optical polarizing device positioned upstream of the optical redirection component relative to the display.

[0046] In some cases, transforming the polarization state of the zero-order light of a display involves transforming the polarization state of the zero-order light of a display by an optical polarizing device positioned downstream of an optical redirection component relative to the display. The optical polarizing device may include an optical retarder and an optical polarizer positioned sequentially downstream of the optical redirection component, the optical retarder may be formed on the side of a second substrate opposite to the optical redirection component, and the optical polarizer may be covered by a third substrate. In some examples, the optical retarder includes a broadband half-wave plate, and the optical polarizer includes a linear polarizer.

[0047] In some implementations, the second substrate includes a first side over the optical redirection component and a second side opposite to the first side. An optical shielding component may be formed on the second side of the second substrate and is configured to transmit the diffracted first portion of light and absorb the zero-order display light diffracted by the optical redirection component.

[0048] In some implementations, the optical blocking component includes an optical anisotropic transmitter configured to transmit a first light beam having an angle smaller than a predetermined angle and absorb a second light beam having an angle larger than a predetermined angle. The predetermined angle can be greater than half the field of view and smaller than the diffraction angle at which the zeroth-order light of the display is diffracted by the optical redirection component.

[0049] In some implementations, the optical redirection component is configured to diffract the zeroth-order display light and direct it to the interface between the second substrate and the surrounding medium at an angle greater than the critical angle, so that the zeroth-order display light diffracted by the optical diffraction component is completely reflected at the interface. A light absorber can be formed on the substrate and the side surfaces of the second substrate and configured to absorb the completely reflected zeroth-order display light.

[0050] In some implementations, the light includes light of multiple different colors, and the optical diffraction component is configured to diffract light of multiple different colors at an angle of incidence on the display.

[0051] In some implementations, an optical redirection component includes a separate optical redirection subcomponent for each of several different colored lights. In some examples, each optical redirection subcomponent for several different colored lights can be recorded in the same recording structure. In some examples, each optical redirection subcomponent for several different colored lights is recorded in a different corresponding recording structure.

[0052] In some implementations, the optical redirection component is configured to diffract multiple different colored lights in 3D space in different directions and at different diffraction angles. The optical redirection component can be configured to diffract at least one of the multiple different colored lights and have it incident at the interface at at least one Brewster angle. The interface may include one of the interfaces between the upper substrate and the surrounding medium, or between two adjacent substrates.

[0053] In some implementations, the optical redirection component is configured to diffract light of a first color and a second color in a plane, as well as light of a third color orthogonal to the plane. In some implementations, the optical redirection component includes at least two different optical redirection subcomponents configured to diffract light of the same color from a plurality of different colors. The two different optical redirection subcomponents can be arranged sequentially within the optical redirection component.

[0054] In some implementations, guiding light to illuminate a display involves sequentially guiding multiple different colored lights to illuminate the display over a series of periods. In some implementations, the optical redirection component includes a switchable optical redirection subcomponent configured to diffract light of a first color in a first state during a first period and transmit light of a second color in a second state during a second period. In some implementations, the optical redirection component includes a switchable optical redirection subcomponent configured to diffract light of a first color in a first state during a first period and diffract light of a second color in a second state during a second period.

[0055] In some implementations, the light of multiple different colors includes a first color and a second color, the first color having a shorter wavelength than the second color, and in the optical redirection component, the first optical redirection subcomponent for the first color of light is positioned closer to the display than the second optical redirection subcomponent for the second color of light.

[0056] In some implementations, the fringe planes of at least two optical redirection subcomponents for at least two different colors of light are oriented in substantially different directions.

[0057] In some implementations, the optical redirection component includes a first optical redirection subcomponent configured to diffract light of a first color, a second optical redirection subcomponent configured to diffract light of a second color, and at least one optical polarizing device positioned between the first and second optical redirection subcomponents and configured to transform the polarization state of the light of the first color so that the light of the first color is transmitted through the second optical redirection subcomponent. The at least one optical polarizing device may include an optical retarder and an optical polarizer positioned sequentially downstream of the first optical redirection subcomponent.

[0058] In some cases, half of the field of view is within the range of -10 to 10 degrees, or -5 to 5 degrees. In some cases, the angle of incidence is -6 degrees or 6 degrees.

[0059] Another aspect of the present disclosure is a method comprising illuminating a display with light, wherein a portion of the light illuminates the display elements of the display, and generating a holographic scene by diffracting a portion of the light while suppressing the zeroth-order display light present in the holographic scene, wherein the zeroth-order display light includes reflected light from the display.

[0060] In some implementations, suppressing display zero-order light present in a holographic scene involves diverging the display zero-order light.

[0061] In some implementations, generating a holographic scene by diffracting the light portion involves modulating the display elements with the hologram. Suppressing the zero-order display light present in the holographic scene may include adjusting the phase range of the hologram.

[0062] In some implementations, illuminating a display with light includes illuminating the display with light at a certain angle of incidence, and suppressing zero-order display light present in a holographic scene may include modulating a portion of the light with a hologram configured such that a portion of the light is diffracted by the display elements at a diffraction angle different from the reflection angle at which the reflected light is reflected. In some cases, suppressing zero-order display light present in a holographic scene may include blocking the zero-order display light with an angle-dependent material. The angle-dependent material may include a metamaterial or an optically anisotropic material.

[0063] In some implementations, suppressing zero-order display light present in a holographic scene includes redirecting zero-order display light. Redirecting zero-order display light may include diffracting zero-order display light with optical diffraction components. The light may contain light of different colors, and redirecting zero-order display light may include diffracting light of different colors in different directions in three-dimensional (3D) space.

[0064] In some implementations, suppressing display zero-order light present in a holographic scene includes suppressing display zero-order light with a light suppression efficiency of a predetermined ratio or higher. Light suppression efficiency is defined as the result of subtracting from 1 the ratio of the amount of display zero-order light in a suppressed holographic scene to the amount of display zero-order light without suppression. The predetermined ratio may be 50%, 60%, 70%, 80%, 90%, or 100%.

[0065] Another feature of the present disclosure is an optical device comprising an optical diffraction component and an optical shielding component. The optical diffraction component is configured to diffract light at a certain angle of incidence to illuminate a display element of a display with a portion of the light, and the optical shielding component is configured to shield the display zeroth order light in a holographic scene formed by the portion of light diffracted by the display element, the display zeroth order light including reflected light from the display.

[0066] In some implementations, optical devices are configured to perform the methods described above.

[0067] In some implementations, the display is configured to be modulated with a hologram corresponding to holographic data, diffracting portions of light to form a holographic scene, and an optical blocking component is configured to transmit the diffracted portions of light to form the holographic scene. The diffracted portions of light can form a reconstructed cone with a viewing angle, and the angle of incidence can be greater than half of the viewing angle.

[0068] The optical blocking component can be configured to transmit a first light beam having an angle smaller than a predetermined angle and to block a second light beam having an angle larger than a predetermined angle, where the predetermined angle can be smaller than the incident angle and larger than half of the field of view.

[0069] In some implementations, the optical shielding component includes a metamaterial layer or an optically anisotropic film. In some implementations, the optical shielding component includes a plurality of microstructures or a plurality of nanostructures.

[0070] In some implementations, the optical device further includes a substrate having both sides. Optical diffraction components and optical shielding components can be formed on both sides of the substrate.

[0071] Another aspect of the present disclosure is characterized by a method for manufacturing such an optical device, comprising forming an optical diffraction element on a first side of a substrate and forming an optical shielding element on a second side of the substrate opposite to the first side.

[0072] Another aspect of the present disclosure features an optical device comprising an optical diffraction component and an optical redirection component. The optical diffraction component is configured to diffract light at a certain angle of incidence onto a display comprising a plurality of display elements spaced apart by gaps on the display. The display is configured to diffract a portion of the light illuminating the display elements. The optical redirection component is configured to transmit a portion of the light to form a holographic scene and redirect zero-order light away from the holographic scene in three-dimensional (3D) space, the display zero-order light including reflected light from the display.

[0073] In some examples, the optical redirection component includes a Bragg grating.

[0074] In some implementations, the optical diffraction component is formed on a first side of the substrate facing the display, and the optical redirection component is formed on a second side of the substrate opposite to the first side.

[0075] In some implementations, the optical device further includes a second substrate covering the optical redirection component. In some implementations, the optical device further includes a light absorber formed on at least one of the sides of the substrate or the side of the second substrate, the light absorber being configured to absorb zero-order display light that is redirected by the optical redirection component and reflected by the interface between the second substrate and the surrounding medium.

[0076] In some implementations, the optical device further includes an anti-reflective coating formed on a second substrate and opposite to the optical redirection component, the anti-reflective coating being configured to transmit the zero-order display light redirected by the optical redirection component.

[0077] In some implementations, the optical device further includes an optical polarizing device configured to convert the polarization state of the display zero-order light from s-polarization to p-polarization before the display zero-order light arrives at a second substrate, and the optical redirection component is configured to diffract the display zero-order light so that it passes through the second substrate and is incident at a Brewster angle at the interface between the second substrate and the surrounding medium. The optical polarizing device may include an optical retarder and a linear polarizer arranged in sequence together.

[0078] In some implementations, the optical polarizing device is positioned upstream of the optical redirection component relative to the display. In some implementations, the optical polarizing device is formed on a second substrate opposite to the optical redirection component, and the optical polarizing device is covered by a third substrate.

[0079] In some implementations, the optical device further includes an optical shielding component formed on a second substrate side opposite to the optical redirection component, the optical shielding component being configured to transmit a portion of the light and absorb the zero-order display light diffracted by the optical redirection component. The optical shielding component may include an optically anisotropic transmitter.

[0080] In some implementations, the optical redirection component is configured to diffract the zeroth-order display light and cause it to be incident at an angle greater than the critical angle at the interface between the second substrate and the surrounding medium, so that the zeroth-order display light diffracted by the optical diffraction component is completely reflected at the interface.

[0081] In some implementations, the light includes light of multiple different colors. An optical diffraction component is configured to diffract light of multiple different colors at an incident angle on the display, and an optical redirection component can be configured to diffract the zero-order light of multiple different colors reflected by the display in different directions in 3D space at different diffraction angles, and the display zero-order light includes the reflected light of multiple different colors by the display.

[0082] In some implementations, the optical diffraction component includes multiple holographic gratings for multiple different colors of light, and each of the multiple holographic gratings is configured to diffract light of each of the multiple different colors at an incident angle on the display.

[0083] In some implementations, the optical redirection component includes multiple redirection holographic gratings for the zeroth-order display light of multiple different colors, each of which is configured to diffract the zeroth-order display light of each of the multiple different colors in its respective direction in 3D space at its respective diffraction angle.

[0084] In some implementations, the optical redirection component includes at least two different redirection holographic gratings configured to diffract the zero-order light of the same color among several different colors of light for display.

[0085] In some implementations, the optical redirection component includes a switchable redirection holographic grating configured to diffract light of a first color in a first state during a first period and transmit light of a second color in a second state during a second period.

[0086] In some implementations, the optical redirection component includes a switchable redirection holographic grating configured to diffract light of a first color in a first state during a first period and to diffract light of a second color in a second state during a second period.

[0087] In some implementations, the light of multiple different colors includes a first color and a second color, the first color having a shorter wavelength than the second color, and in the optical redirection component, the first redirection holographic grating for the first color of light is positioned closer to the display than the second redirection holographic grating for the second color of light.

[0088] In some implementations, the fringe planes of at least two redirect holographic gratings for at least two different colors of light are oriented in substantially different directions.

[0089] In some implementations, the optical redirection component includes a first redirection holographic grating configured to diffract light of a first color, a second redirection holographic grating configured to diffract light of a second color, and at least one optical polarizing device positioned between the first redirection holographic grating and the second redirection holographic grating and configured to convert the polarization state of the light of the first color so that the light of the first color is transmitted through the second redirection holographic grating.

[0090] In some implementations, the optical device is configured to perform the method described above.

[0091] Another aspect of the present disclosure features a method for manufacturing such an optical device, comprising forming an optical diffraction component on a first side of a substrate and forming an optical redirection component on a second side of the substrate opposite to the first side.

[0092] Another aspect of the present disclosure features a system including a display comprising display elements separated by a gap on the display, and an optical device configured to illuminate the display with light, wherein a portion of the light illuminates the display elements. The system is configured to form a holographic scene by diffracting portions of light while suppressing zero-order display light in the holographic scene. The zero-order display light may include at least one of reflected light from the gap, diffracted light from the gap, reflected light from the display elements, or reflected light from a display cover that surrounds the display.

[0093] In some implementations, the system further includes a controller coupled to the display and configured to modulate the display elements of the display with a hologram corresponding to holographic data, thereby diffracting the light portion and forming a holographic scene corresponding to the holographic data. The hologram can be configured such that zero-order display light is suppressed within the holographic scene.

[0094] In some implementations, the system further includes a computing device configured to generate primitives of one or more objects corresponding to a holographic scene. The system can be configured to perform such a method. The optical device may include one or more of the optical devices described above.

[0095] In some implementations, the system further includes an optical divergent device positioned downstream of the optical device and configured to diverge the zero-order light of the display within the holographic scene. The light illuminating the display is collimated light. The zero-order light of the display is collimated before reaching the optical divergent device, and the hologram is configured such that the diffracted portions of the light converge before reaching the optical divergent device. The optical divergence device may include the optical divergence components described above.

[0096] In some implementations, the system further includes a two-dimensional (2D) screen positioned downstream of the display. In some implementations, the optical device includes a beam splitter. In some implementations, the optical device includes a waveguide having in-couplers and out-couplers. In some implementations, the optical device includes a light guide including an optical coupler and an optical diffraction component. The optical coupler may include a coupling prism. The optical coupler may also include a wedge-shaped substrate.

[0097] Another aspect of this disclosure is characterized by a method for creating such a system.

[0098] Another aspect of the present disclosure features an optical device comprising at least two beam expanders configured to expand an input light beam of at least two dimensions by diffracting the input light beam and adjusting the beam size of the input light beam of at least two dimensions to produce an output light beam. The beam size may include width and height.

[0099] In some implementations, each of the at least two beam expanders includes its own optical diffraction device. The input light beam may contain light of multiple different colors, and each optical diffraction device may be configured to diffract light of multiple different colors at their respective diffraction angles, which are substantially identical to each other.

[0100] In some examples, each optical diffraction device is configured to separate individual light of different colors while suppressing crosstalk between them, when light of different colors is incident on it.

[0101] In some implementations, each optical diffraction device includes at least two optical diffraction components and at least one color-selective polarizer.

[0102] In some implementations, each optical diffraction device includes at least two optical diffraction components and at least one reflective layer. The at least one reflective layer may be configured for total internal reflection of light of at least one color.

[0103] In some implementations, each optical diffraction device includes at least one of one or more transmission diffraction structures or one or more reflection diffraction structures.

[0104] In some implementations, the beam expander includes at least two beam expanders: a first one-dimensional beam expander configured to expand an input optical beam of a first dimension of at least two dimensions to produce an intermediate optical beam; and a second one-dimensional beam expander configured to expand an intermediate optical beam of a second dimension of at least two dimensions to produce an output optical beam. The intermediate optical beam has a beam size larger than that of the input optical beam of the first dimension and the same beam size as the input optical beam of the second dimension, and the output optical beam has a beam size larger than that of the intermediate optical beam of the second dimension and the same beam size as the intermediate optical beam of the first dimension.

[0105] In some implementations, the optical device is configured to couple an intermediate light beam from a first one-dimensional beam expander to a second one-dimensional beam expander using at least one of free-space aerial geometry, a monolithic substrate or a segmented substrate, or one or more coupling elements.

[0106] In some implementations, the intermediate input beam includes collinear, collimated light of two or more colors, and one or more coupling elements are configured to convert the collinear, collimated light of two or more colors into two or more independently parallel but non-collinear light beams having corresponding colors of two or more colors.

[0107] This disclosure also describes, in particular, methods, apparatus, devices, and systems for displaying three-dimensional (3D) objects by individually diffracting light of different colors. This disclosure provides techniques that can efficiently separate light of different colors or wavelengths to suppress (e.g., reduce or eliminate) crosstalk between colors or wavelengths. The techniques can also suppress light from propagating through an optical diffraction device without diffraction and striking the display at undesirable angles, thereby suppressing undesirable effects such as ghost images. The techniques enable the sequential or simultaneous reconstruction of multi-color three-dimensional optical fields or images with little to no crosstalk. The techniques enable the implementation of an illumination system to provide multiple nearly perpendicular polarized beams of different colors with relatively large incident angles. Thus, the techniques enable the presentation of an optical field or image to a viewer in front of the display (e.g., an observer or user) without interference from the illuminator, and reduce power loss due to reflection, diffraction, and / or scattering, for example. The techniques also enable the implementation of a compact optical system for displaying three-dimensional objects.

[0108] This disclosure provides a technology that can overcome the limitations present in known technologies. For example, the technology disclosed herein can be implemented without the use of cumbersome wearable devices such as "3D glasses." Alternatively, the technology disclosed herein can be optionally implemented without being limited by the accuracy of the tracking mechanism, the quality of the display device, relatively long processing times and / or relatively high computational requirements, and / or the inability to display objects simultaneously to multiple viewers. Further, the technology can be implemented without dedicated tools and software for developing content that extends beyond the tools and software used for conventional 3D content creation. Various embodiments can demonstrate one or more of the aforementioned advantages. For example, a particular implementation of this disclosure can generate real-time, full-color, authentic 3D images that appear to be real 3D objects in the world and can be simultaneously and uninterruptedly viewed by multiple viewers from different points of view.

[0109] One aspect of the present disclosure is a method comprising: determining the EM field contribution to each of the elements of a display by calculating the electromagnetic field propagation from the primitive to the element in a 3D coordinate system for each of the primitives corresponding to an object in three-dimensional (3D) space; and generating the sum of the EM field contributions from the primitives to the element for each of the elements.

[0110] An EM field contribution may include at least one of a phase contribution or an amplitude contribution. A primitive may include at least one of a point primitive, a line primitive, or a polygon primitive. A primitive may include a line primitive that includes at least one of a gradient color, a texture color, or any surface shading effect. A primitive may also include a polygon primitive that includes at least one of a gradient color, a texture color, or any surface shading effect. Multiple primitives may be indexed in a specific order.

[0111] In some implementations, the method further includes obtaining primitive data for each of a plurality of primitives. Each primitive data for each of the plurality of primitives may include the respective color information of the primitive, and the determined EM field contribution of each element includes information corresponding to the respective color information of the primitive. The color information may include at least one of texture color or gradient color. Each primitive data for each of the plurality of primitives may include the texture information of the primitive. Each primitive data for each of the plurality of primitives may include shading information on one or more surfaces of the primitive. The shading information may include modulation of at least one of color or luminance on one or more surfaces of the primitive.

[0112] In some implementations, the primitive data for each of multiple primitives includes the coordinate information of the primitive in a 3D coordinate system. The coordinate information of each of multiple elements in a 3D coordinate system can be determined based on the coordinate information of each of the multiple primitives in a 3D coordinate system. The coordinate information of each element can correspond to the logical memory address of the element stored in memory.

[0113] Determining the EM field contribution of each of the elements for each of the multiple primitives may include determining at least one distance between the elements and the primitives in a 3D coordinate system, based on the coordinate information of each element and the coordinate information of each primitive. In some examples, determining the EM field contribution of each of the elements for each of the multiple primitives may include determining a first distance between the first primitive and the first element of the multiple primitives, based on the coordinate information of each of the first primitives and the coordinate information of each of the first elements, and determining a second distance between the first primitive and the second element of the multiple elements, based on the first distance and the distance between the first element and the second element. The distance between the first and second elements may be predetermined based on the pitch of the multiple elements of the display.

[0114] In some examples, at least one of the multiple primitives is a line primitive including a first endpoint and a second endpoint, and determining at least one distance between the element and the primitive includes determining a first distance between the element and the first endpoint of the line primitive and determining a second distance between the element and the second endpoint of the line primitive. In some examples, at least one of the multiple primitives is a triangle primitive including a first endpoint, a second endpoint and a third endpoint, and determining at least one distance between the element and the primitive includes determining a first distance between the element and the first endpoint of the triangle primitive, determining a second distance between the element and the second endpoint of the triangle primitive and determining a third distance between the element and the third point of the triangle primitive.

[0115] In some implementations, determining the EM field contribution of each of several elements for each of several primitives involves determining the EM field contribution from the primitive to the element based on a predetermined equation for the primitive and at least one distance. In some cases, the predetermined equation is determined by analytically calculating the EM field propagation from the primitive to the element. In some cases, the predetermined equation is determined by solving Maxwell's equations. Maxwell's equations can be solved by providing boundary conditions defined on the surface of the display. The boundary conditions may include Dirichlet or Cauchy boundary conditions. The several primitives and several elements may be in 3D space, and the surface of the display may form a portion of the boundary surface of 3D space. In some cases, the predetermined equation includes at least one function, including a sine function, a cosine function, or an exponential function, and determining the EM field contribution involves identifying at least one value of the function in a table stored in memory.

[0116] In some implementations, determining the EM field contribution of each of the multiple elements for each of the multiple primitives and generating the sum of the field contributions for each of the multiple elements includes determining the first EM field contribution from the multiple primitives to the first element among the multiple elements, summing the first EM field contribution for the first element, determining the second EM field contribution from the multiple primitives to the second element among the multiple elements, and summing the second EM field contribution for the second element. Determining the first EM field contribution from the multiple primitives to the first element may include performing in parallel the determination of the EM field contribution from the first primitive among the multiple primitives to the first element, and the determination of the EM field contribution from the second primitive among the multiple primitives to the first element.

[0117] In some implementations, determining the EM field contribution of each of the elements for each of the multiple primitives includes determining the first EM field contribution of each of the elements from a first primitive among the multiple primitives, and determining the second EM field contribution of each of the elements from a second primitive among the multiple primitives, and generating the sum of the field contributions for each of the elements may include accumulating the EM field contribution for an element by adding the second EM field contribution to the first EM field contribution for that element. Determining the first EM field contribution of each of the elements from the first primitive can be performed in parallel with determining the second EM field contribution of each of the elements from the second primitive.

[0118] Determining the EM field contribution of each of the multiple elements for each of the multiple primitives may include, in parallel, determining the first EM field contribution from the first primitive among the multiple primitives to the first element among the multiple elements, and determining the second EM field contribution from the second primitive among the multiple primitives to the first element.

[0119] In some implementations, the method further includes generating a control signal for each of a plurality of elements based on the sum of the EM field contributions from a plurality of primitives to the element, wherein each control signal is for tuning at least one property of the element based on the sum of the EM field contributions from the plurality of primitives to the element. The at least one property of the element may include at least one of refractive index, amplitude exponent, birefringence, or delay. Each control signal may include an electrical signal, optical signal, magnetic signal, or acoustic signal. In some cases, the method further includes multiplying the sum of the field contributions for each of the elements by a scaling factor to obtain a scaled sum of the field contributions, and each control signal is generated based on the scaled sum of the field contributions for the element. In some cases, the method further includes normalizing the sum of the field contributions for each of the elements, and each control signal is based on the normalized sum of the field contributions for the element. The method may also include transmitting each control signal to the element.

[0120] In some implementations, the method further includes transmitting a control signal to an irradiator, the control signal indicating that the irradiator is to act as such that it emits light onto a display. The control signal may be transmitted in response to determining the completion of obtaining the sum of the field contributions for each of a plurality of elements. Modulated elements of the display can propagate light in different directions to form a volume light field corresponding to an object in 3D space. The volume light field may correspond to a solution of Maxwell's equations having boundary conditions defined by the modulated elements of the display. The light may include white light, and the display may be configured to diffract the white light into light having different colors.

[0121] In some implementations, the method further includes representing values ​​using fixed-point representation during computation. Each value can be represented as an integer with an implicit scaling factor.

[0122] In some implementations, the method further includes performing mathematical functions using fixed-point representations. Mathematical functions may include at least one of sine, cosine, and arctangent. Performing a mathematical function may include receiving an expression in a first fixed-point format and outputting a value in a second fixed-point format having a different level of precision than the first fixed-point format. Performing a mathematical function may include examining a table for the calculation of the mathematical function, the table including at least one of fully enumerated lookup tables, interpolated tables, half-table-based polynomial functions, and half-tables based on full minimax polynomials. Performing a mathematical function may include applying special range reductions to the input. Performing a mathematical function may include converting trigonometric function calculations from the range [-π,π] to signed 2 representations within the range [-1,1].

[0123] Another aspect of the present disclosure features a method comprising: obtaining primitive data for each of a plurality of primitives corresponding to an object in three-dimensional (3D) space; calculating a first electromagnetic (EM) field contribution from a first primitive among the plurality of primitives to each of a plurality of elements of a display; and calculating a second EM field contribution from a second primitive among the plurality of primitives to each of a plurality of elements of a display. The calculation of the first EM field contribution from the first primitive is at least partially parallel to the calculation of the second EM field contribution from the second primitive.

[0124] In some implementations, the calculation of the first EM field contribution from a first primitive to a first element of multiple elements is parallel to the calculation of the second EM field contribution from a second primitive to the first element of multiple primitives. The method may include calculating the respective EM field contribution from each of the multiple primitives to each of the multiple elements. The calculation of each EM field contribution may be without extending the geometry of the object to multiple elements, applying visibility tests before packing wavefronts, and making decisions or communicating between parallel calculations for different primitives. The calculation of each EM field contribution may be configured to cause at least one of the following: adjusting the parallel calculations for different primitives to speed, cost, size, or energy optimization; reducing the delay between initiating drawing and the results being ready for display; improving accuracy by using fixed-point representations; and optimizing the calculation speed by optimizing mathematical functions.

[0125] In some implementations, the method further includes representing values ​​using fixed-point representation during computation. Representing values ​​using fixed-point representation can proceed without denormalizing floats for gradual underflow, handling NaN results from operations including division by zero, changing floating-point rounding modes, and raising floating-point exceptions in the operating system.

[0126] In some implementations, the method further includes accumulating the EM field contributions for each of the elements by adding the second EM field contribution for each element to the first EM field contribution for each element.

[0127] In some implementations, the method further includes generating, for each of a plurality of elements, a control signal based on the sum of the EM field contributions from a plurality of primitives to the element, wherein each control signal is for tuning at least one property of the element based on the sum of the EM field contributions from the plurality of primitives to the element.

[0128] In some implementations, the method further includes scaling the first primitive adjacent to the second primitive by a predetermined coefficient such that the reconstruction of the first primitive does not overlap with the reconstruction of the second primitive. The predetermined coefficient can be determined at least in part on the resolution of the display. The method may further include obtaining primitive data for each of a plurality of primitives, wherein the primitive data for each of the plurality of primitives includes coordinate information for each primitive in a 3D coordinate system, and determining new coordinate information for each of the first primitives based on the coordinate information for each of the first primitives and the predetermined coefficient. The method may further include determining the EM field contribution from the first primitive to each of a plurality of elements based on the new coordinate information for each of the first primitives. The method may further include scaling the second primitive by a predetermined coefficient. The first primitive and the second primitive may share a common part, and scaling the first primitive includes scaling the common part of the first primitive. Scaling the first primitive may include scaling the first primitive in a given direction.

[0129] Another aspect of the present disclosure is a method comprising: obtaining primitive data for each of a plurality of primitives corresponding to an object in three-dimensional (3D) space; scaling the first primitive adjacent to the second primitive by a predetermined coefficient using the respective primitive data for the first primitive and the second primitive; and updating the respective primitive data for the first primitive based on the scaling result.

[0130] In some implementations, each primitive data of multiple primitives includes coordinate information for each primitive in a 3D coordinate system, and updating each primitive data includes determining the new coordinate information for each first primitive based on the coordinate information of each first primitive and predetermined coefficients.

[0131] In some implementations, a predetermined coefficient is determined such that the reconstruction of the first primitive does not overlap with the reconstruction of the second primitive in 3D space.

[0132] In some implementations, scaling is performed such that the gap between the reconstruction of the first and second primitives in 3D space is large enough to separate the first and second primitives and minimize overlapping effects, and small enough to make the reconstruction appear seamless.

[0133] In some implementations, a predetermined coefficient is determined at least partially based on the display resolution, or based on the actual or assumed distance from the viewer to the display, or the z-depth of primitives in the 3D space of the display.

[0134] In some implementations, the method further includes storing updated primitive data for the first primitive in a buffer.

[0135] In some implementations, scaling is performed during the rendering process of an object to retrieve the primitive data for each of multiple primitives.

[0136] In some implementations, the method further includes transmitting updated primitive data for a plurality of primitives to a controller, which is configured to determine, based on the updated primitive data for the plurality of primitives, the respective electromagnetic (EM) field contribution from each of the plurality of primitives to each of the plurality of elements of the display.

[0137] In some implementations, the method further includes determining the EM field contribution from the first primitive to each of the multiple elements of the display, based on the updated primitive data of the first primitive.

[0138] In some implementations, the method further includes scaling a second primitive by a predetermined coefficient.

[0139] In some implementations, the first primitive and the second primitive share a common part, and scaling the first primitive includes scaling the common part of the first primitive.

[0140] In some implementations, scaling a first primitive includes scaling the first primitive in a predetermined direction.

[0141] In some implementations, scaling a first primitive includes scaling a first portion of the first primitive by a first predetermined coefficient and scaling a second portion of the second primitive by a second predetermined coefficient, wherein the first predetermined coefficient is different from the second predetermined coefficient.

[0142] Another aspect of the present disclosure features a method comprising: obtaining a plurality of discrete cosine transform (DCT) weights of an image mapped onto a specific surface of a particular primitive among a plurality of primitives corresponding to an object in three-dimensional (3D) space; and determining the respective EM field contributions from the particular primitive to each of a plurality of elements of the display by taking into account the effects of the plurality of DCT weights of the image.

[0143] In some implementations, the method further includes determining the resolution of an image mapped onto a specified surface of a particular primitive, and determining multiple DCT weights of the image based on the resolution.

[0144] In some implementations, the method further includes decoding the DCT weights of the image to obtain the respective DCT amplitude for each pixel of the image.

[0145] In some implementations, the method further includes storing a value associated with the DCT amplitude of each pixel in the image, along with the primitive data of a particular primitive. Determining each EM field contribution may include calculating the respective EM field contribution from a particular primitive to each of several elements using the value associated with the DCT amplitude of each pixel in the image.

[0146] In some implementations, the method further includes selecting specific DCT terms to be included in the determination of each EM field contribution, each of which has a DCT weight higher than a predetermined threshold.

[0147] Another aspect of the present disclosure is characterized by a method for obtaining information on a given primitive and an occluder of a given primitive, wherein the given primitive is located within a plurality of primitives corresponding to an object in three-dimensional (3D) space, and determining one or more specific elements of a plurality of elements of a display that do not contribute to the reconstruction of the given primitive as an effect of the occluder.

[0148] In some implementations, the method further includes storing information about a particular element together with information about a given primitive and occluder.

[0149] In some implementations, the decision is made during the rendering process of an object to obtain primitive data for multiple primitives.

[0150] In some implementations, the method further includes transmitting stored information of a particular element, along with information of a given primitive and occluder, to a controller configured to calculate the electromagnetic (EM) contributions of multiple primitives to multiple elements of a display.

[0151] In some implementations, the method further includes generating the sum of electromagnetic (EM) field contributions from multiple primitives to one of the specific elements by subtracting the EM field contribution from a given primitive to one of the specific elements for each of the specific elements.

[0152] In some implementations, the method further includes generating the sum of the respective EM field contributions from multiple primitives to the element for each of multiple elements other than a specific element.

[0153] In some implementations, the method further includes masking the EM field contribution of a particular element to a given primitive.

[0154] In some implementations, determining one or more specific elements includes connecting a given primitive to the endpoints of an occluder, extending the connection to a display and determining the intersection of the connection and the display, and determining that a specific range defined by the intersection is a specific element that does not contribute to the reconstruction of the given primitive by the effect of the occluder.

[0155] Another aspect of the present invention is a method for obtaining information on a given primitive and an occluder of a given primitive, wherein the given primitive is located within a plurality of primitives corresponding to an object in three-dimensional (3D) space, and for each of a plurality of elements of a display, determining which parts of the given primitive do not make an electromagnetic (EM) field contribution to the element as an effect of the occluder.

[0156] In some implementations, the method further includes storing information about each part of a given primitive, along with information about the primitive and the occluder.

[0157] In some implementations, the decision is made during the rendering process of an object to obtain primitive data for multiple primitives.

[0158] In some implementations, the method further includes transmitting the stored information of each part of a given piece of information, together with a given primitive and occluder information, to a controller configured to calculate the electromagnetic (EM) contributions of a plurality of primitives to a plurality of elements of a display.

[0159] In some implementations, the method further includes masking the EM field contribution of each of the multiple elements to each part of a given primitive.

[0160] In some implementations, the method further includes generating a sum of EM field contributions from multiple primitives to an element by subtracting the EM field contribution from each part of a given primitive to the element for each of the multiple elements. Generating a sum of EM field contributions from multiple primitives to an element may include subtracting the EM contribution from each part of a given primitive to the element from the sum of EM field contributions from multiple primitives to an element, without the effect of an occluder. Generating a sum of EM field contributions from multiple primitives to an element may include summing the EM field contributions from one or more other parts of a given primitive to the element, each part and one or more other parts forming a given primitive.

[0161] In some implementations, determining which parts of a given primitive do not contribute to the EM field of an element as an effect of the occluder includes connecting the element to the endpoints of the occluder, determining the intersections of the connections and the given primitive, and determining which parts of the given primitive enclosed by the intersections are the parts of the given primitive that do not contribute to the EM field of the element as an effect of the occluder.

[0162] Another aspect of the present disclosure is characterized by a method comprising: obtaining primitive data for each of a plurality of primitives corresponding to an object in three-dimensional (3D) space; obtaining geometric specular information for each of the plurality of primitives; and storing the primitive data and geometric specular information for each of the plurality of primitives.

[0163] In some implementations, the geometric specular information for each of the multiple primitives includes the reflectance of the primitive's surface in the field of view.

[0164] In some implementations, the method further includes determining the respective EM field contribution from each of several primitives to each of several elements of the display by considering the respective geometric specular information for each primitive.

[0165] Another aspect of the present disclosure features a method comprising: acquiring graphic data including primitive data for a plurality of primitives corresponding to an object in three-dimensional (3D) space; determining the electromagnetic (EM) field contribution to each of the plurality of elements of a display by calculating the EM field propagation from the primitive to the element in a 3D coordinate system for each of the plurality of primitives; generating a sum of the EM field contributions from the plurality of primitives to the element for each of the plurality of elements; transmitting a control signal to each of the plurality of elements, wherein the control signal is for modulating at least one characteristic of the element based on the sum of the EM field contributions to the element; and transmitting a timing control signal to an illuminator to irradiate the display with light, such that light is caused by the modulated elements of the display to form a volume light field corresponding to an object.

[0166] Another aspect of the present disclosure is a method comprising: modifying each of a plurality of elements of a display by a predetermined calibration value; applying the modified control signals to the plurality of elements of the display; measuring the output of light incident on the display; and evaluating a predetermined calibration value based on the measurement of the light output.

[0167] In some implementations, the predetermined calibration value is the same for each of the multiple elements.

[0168] In some implementations, the method further includes converting the respective control signals of multiple elements by a digital-to-analog converter (DAC), and modifying the respective control signals for multiple elements includes modifying the digital signals of each control signal by a predetermined calibration value.

[0169] In some implementations, a given value includes multiple bits.

[0170] In some implementations, the method further includes adjusting a predetermined calibration value based on the results of an evaluation. Adjusting a predetermined calibration value may include modifying the value of one or more of a plurality of bits. Adjusting a predetermined calibration value may also include determining a combination of values ​​for a plurality of bits based on the predetermined calibration value and another calibration value determined from a previous evaluation.

[0171] In some implementations, the light output includes a phase change of light, or an intensity difference between the light output and the background.

[0172] In some implementations, the control signal for each element is determined based on the sum of the electromagnetic (EM) field contributions from multiple primitives corresponding to the object in 3D space to the element.

[0173] Another aspect of the present disclosure is a method for obtaining, for each of a plurality of elements of a display, the respective sums of electromagnetic (EM) field contributions from a plurality of primitives in three-dimensional (3D) space, wherein the plurality of primitives correspond to objects in 3D space, the method comprising: obtaining; applying the respective mathematical transformations to the respective sums of EM field contributions for each element to obtain the respective transformed sums of EM field contributions for each element; determining the respective control signals based on the respective determined control signals for each element.

[0174] In some implementations, the method further includes introducing light incident on multiple elements of a display, measuring a first output of light, and adjusting one or more coefficients of the respective mathematical transformations of the multiple elements based on the measurement of the first output of light. The method may further include changing the depth of the holographic pattern corresponding to an object, taking the display into consideration, measuring a second output of light, and adjusting one or more coefficients of the respective mathematical transformations based on the first and second outputs. The method may further include changing a plurality of primitives corresponding to a first holographic pattern to a second plurality of primitives corresponding to a second holographic pattern, measuring a second output of light, and adjusting one or more coefficients of the respective mathematical transformations based on the first and second outputs. The first and second holographic patterns may correspond to objects. The second holographic pattern may correspond to a second object different from the object associated with the first holographic pattern. The first light output can be measured by an imaging sensor (e.g., a point sensor, a spatially integrated sensor, or a three-dimensional sensor such as a light field sensor). The imaging sensor can be configured to use a machine vision algorithm to determine what is being displayed and calculate fit parameters. Each of the first and second holographic patterns may include a grid of dots or other reference elements, and the fit parameters are at least one of the following: how close the dots or other reference elements are together; how close the dots or other reference elements are to the color and intensity of the intended positions; how well the dots or other reference elements are centered relative to the intended positions; and how distorted the dots or other reference elements are.

[0175] In some implementations, the mathematical transformation is derived from Zernike polynomials.

[0176] In some implementations, the mathematical transformation for multiple elements varies from element to element.

[0177] In some implementations, the method further includes reproducing a sample set of known colors and intensities by illuminating a display, measuring the output light using a colorimetric device that can be calibrated to a CIE standard observer curve, and defining the output light of the display in a color space such as the CIE color space. The method may further include determining the deviation of the defined output light values ​​from known standard values, adapting the illumination to the display, or adapting the generation of output colors and intensities by the display to align them back to a conformity with standard or desired values.

[0178] Another aspect of the present disclosure features a method comprising determining the cell gap of a liquid crystal (LC) display based on the pitch of the display elements of the LC display, and calculating the minimum birefringence of an LC mixture based on the cell gap and a predetermined delay of the LC display.

[0179] In some implementations, the method further includes improving the switching speed of an LC display by keeping the birefringence of the LC mixture above a minimum value. Improving the switching speed may include at least one of increasing the dielectric anisotropy of the LC mixture and decreasing the rotational viscosity of the LC mixture.

[0180] In some implementations, the LC display includes a liquid crystal on silicon (LCOS or LCoS) device having a silicon backplane.

[0181] In some implementations, the LC display includes a liquid crystal layer, a transparent conductive layer located above the liquid crystal layer as a common electrode, and a backplane having a plurality of metal electrodes located above or electrically close to the bottom of the liquid crystal layer, each of the plurality of metal electrodes being isolated from one another, and the backplane is configured to control the voltage of each of the plurality of metal electrodes.

[0182] Another aspect of the present disclosure features a display comprising a backplane and a plurality of display elements on the backplane, wherein at least two of the plurality of display elements are of different sizes.

[0183] In some implementations, the larger of at least two display elements is equipped with a buffer, while the smaller of at least two display elements is not equipped with a buffer. The larger display element can be connected to a first plurality of display elements by conductive wires, and the buffer is configured to buffer the voltage applied to the conductive wires such that the voltage is applied only to the second plurality of display elements within the first plurality of display elements, and some of the second plurality of display elements are smaller than some of the first plurality of display elements.

[0184] In some implementations, the buffer comprises an analog circuit in the form of a transistor or a digital circuit in the form of a logic gate.

[0185] In some implementations, the size distribution of multiple display elements is substantially the same as the size of the smaller of at least two display elements.

[0186] In some implementations, the display is configured to be a liquid crystal on silicon device.

[0187] Another aspect of the present disclosure features a display comprising a backplane and a plurality of display elements on the backplane, wherein at least two of the plurality of display elements have different shapes.

[0188] In some implementations, the backplane includes a circuit for each of the display elements, and each circuit for at least two display elements has a shape corresponding to the different shapes of at least two display elements.

[0189] In some implementations, the size distribution of multiple display elements is substantially the same as a predetermined size.

[0190] In some implementations, the display is configured to be a liquid crystal on silicon device.

[0191] Another aspect of the present disclosure features a method comprising: acquiring graphic data including primitive data for a plurality of primitives corresponding to an object in three-dimensional (3D) space; determining the electromagnetic (EM) field contribution to each of the plurality of elements of a display by calculating the EM field propagation from the primitive to the element in a 3D coordinate system for each of the plurality of primitives; generating a sum of the EM field contributions from the plurality of primitives to the element for each of the plurality of elements; transmitting a control signal to each of the plurality of elements, wherein the control signal is for modulating at least one characteristic of the element based on the sum of the EM field contributions to the element; and transmitting a timing control signal to an illuminator to irradiate the display with light, such that light is caused by the modulated elements of the display to form a volume light field corresponding to an object.

[0192] Other embodiments of the model include corresponding computer systems, devices, and computer programs recorded on one or more computer storage devices, each configured to perform the actions of the method. The configuration of one or more computer systems to perform a particular operation or action means that the systems have installed software, firmware, hardware, or a combination thereof that causes the systems to perform the operation or action while in operation. The configuration of one or more computer programs to perform a particular operation or action means that one or more programs, when executed by a data processing device, contain instructions that cause the device to perform the operation or action.

[0193] Another aspect of the present disclosure features a device comprising one or more processors and a non-temporary computer-readable storage medium that communicates with the one or more processors, is executable by the one or more processors, and stores instructions that, when executed, cause the one or more processors to perform one or more of the methods disclosed herein.

[0194] Another aspect of the present disclosure features a non-temporary computer-readable storage medium that is executable by one or more processors and, during such execution, stores instructions causing one or more processors to perform a method according to one or more of the methods disclosed herein.

[0195] Another aspect of this disclosure features a display comprising a plurality of elements and a controller coupled to the display and configured to perform one or more of the methods disclosed herein. The controller may comprise a plurality of computing units, each of which is configured to perform operations on one or more primitives of a plurality of primitives corresponding to objects in three-dimensional (3D) space. In some implementations, the controller is coupled locally to the display, and each computing unit is coupled to one or more respective elements of the display and configured to transmit respective control signals to each of the one or more respective elements. The computing units may be configured to operate in parallel.

[0196] The controller may include at least one of the following: an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a programmable gate array (PGA), a central processing unit (CPU), a graphics processing unit (GPU), or a standard or custom computing cell. The display may include a spatial light modulator (SLM) including a digital micromirror device (DMD) or a liquid crystal on silicon (LCOS or LCoS) device. The display may be configured to be phase-modulated, amplitude-modulated, or phase and amplitude-modulated. The controller may be coupled to the display through a memory buffer.

[0197] In some implementations, the system includes an irradiator positioned adjacent to the display and configured to emit light onto the display. The irradiator may be coupled to a controller and configured to be turned on / off based on a control signal from the controller.

[0198] In some cases, the irradiator is coupled to a controller through a memory buffer configured to control the amplitude or brightness of one or more light-emitting elements within the irradiator. The memory buffer for the irradiator may be smaller in size than the memory buffer for the display. Some of the light-emitting elements within the irradiator may be smaller than some of the elements of the display. The controller may be configured to operate one or more of the light-emitting elements of the irradiator simultaneously or sequentially.

[0199] The irradiator may be a coherent light source, a semi-coherent light source, or an incoherent light source. In some implementations, the irradiator is configured to emit white light, and the display is configured to diffract the white light into light having different colors. In some implementations, the irradiator includes two or more light-emitting elements, each configured to emit light having a different color. The controller may be configured to sequentially modulate the display with information associated with a first color during a first period, and to modulate the display with information associated with a second color during a second consecutive period, and the controller may be configured to control the irradiator to sequentially operate the first light-emitting element to emit light having a first color during the first period, and the second light-emitting element to emit light having a second color during the second period.

[0200] In some implementations, the irradiator is positioned in front of the display surface and configured to emit light onto the display surface at an incident angle in the range of 0 to 90 degrees, and the emitted light is diffracted from the display. In some cases, the light emitted from the irradiator includes collimated light. In some cases, the light emitted from the irradiator includes divergent light. In some cases, the light emitted from the irradiator includes focused light. In some cases, the light emitted from the irradiator includes semi-collimated light.

[0201] In some implementations, the irradiator is positioned behind the back of the display and is configured to emit divergent collimated, semi-collimated, or focused light onto the back of the display, which is transmitted through the display and diffracted from the front of the display.

[0202] In some implementations, the illuminator includes a light source configured to emit light, and a waveguide coupled to the light source and positioned adjacent to the display, wherein the waveguide is configured to receive the light emitted from the light source and guide the emitted light to the display. In some cases, the light from the light source is coupled to the waveguide from the side cross section of the waveguide via an optical coupler. In some cases, the light source and the waveguide are integrated in a planar form and positioned on the surface of the display. The waveguide can be configured to guide the light to uniformly illuminate the display.

[0203] In some cases, the waveguide is positioned on or optically close to the back of the display, and light is guided to pass through the display, transmitted, and diffracted from the front of the display. The controller can be positioned on the back of the waveguide. In some cases, the waveguide or light guide is positioned on or optically close to the front of the display, and light is guided to enter the front of the display, passed through the front, reflected backward, and diffracted.

[0204] Another aspect of the present disclosure is an integrated circuit comprising a display including an array of elements and an array of computing units, each of which computing units is coupled to one or more of the elements of the display, and which calculates the electromagnetic (EM) field contribution to each of the element arrays from at least one primitive among a plurality of primitives, and for one or more of the elements, The system comprises an integrated circuit configured to generate the sum of the respective EM field contributions from multiple primitives to an element.

[0205] Each computing unit can be configured to receive computed EM field contributions from other computing units in an array of computing units to each of one or more elements from other primitives, and to generate each sum of EM field contributions by adding the received computed EM field contributions from other primitives to each of the one or more elements.

[0206] Each computing unit can be configured to generate a control signal for each of the one or more elements to modulate at least one characteristic of the element, based on the sum of the respective EM field contributions to the element.

[0207] In some implementations, the integrated circuit includes each accumulator configured to store the cumulative result of the calculated EM field contributions from multiple primitives to each of the elements of the display. The integrated circuit may be configured to clear the accumulator at the start of the calculation operation. In some examples, the integrated circuit includes each memory buffer for each of the elements, and the integrated circuit may be configured to accumulate the calculated EM field contributions from multiple primitives to the elements, obtain each sum of the EM field contributions as the final accumulation result in each accumulator, and transfer the final accumulation result from each accumulator to the respective memory buffer of the elements.

[0208] In some implementations, the system further includes an illuminator positioned between the integrated circuit and the display, configured to receive control signals from the integrated circuit and to illuminate the display with light based on the control signals, and the integrated circuit, the illuminator, and the display can be integrated as a single unit.

[0209] Another aspect of this disclosure features a system including a computing device configured to generate data containing primitive data for each of a plurality of primitives corresponding to an object in three-dimensional (3D) space, and a system as disclosed herein. The system is configured to receive graphic data from the computing device and to process the graphic data to present the object in 3D space. The computing device may include an application programming interface (API) configured to create primitives with each primitive data by rendering a computer-generated (CG) model of the object.

[0210] Another aspect of this disclosure is: A first optical diffraction component, a second optical diffraction component, and The optical device is characterized by a color-selective polarizer between a first optical diffraction component and a second optical diffraction component. When a first light beam containing light of a first color in a first polarization state is incident on the first optical diffraction component, the first optical diffraction component diffracts the light of a first color in the first polarization state. When a second light beam containing light of a second color in a second polarization state is incident on the color-selective polarizer, the color-selective polarizer converts the second light beam into a third light beam containing light of a second color in a first polarization state, the second color being different from the first color, and the second polarization state being different from the first polarization state. When the third light beam is incident on the second optical diffraction component, the second optical diffraction component diffracts the light of a second color in the first polarization state. The diffraction efficiency of the first optical diffraction component in diffracting the light of a second color in the second polarization state is substantially smaller than the diffraction efficiency of the first optical diffraction component in diffracting the light of a first color in the first polarization state.

[0211] Another aspect of the present disclosure features an optical device comprising a first optical diffraction component, a second optical diffraction component, and a color-selective polarizer between the first optical diffraction component and the second optical diffraction component. When light of a first color is incident on a first optical diffraction component at a first angle of incidence and in a first polarization state, the first optical diffraction component diffracts the light of the first color at a first diffraction angle with a first diffraction efficiency; when light of a second color different from the light of the first color is incident on the first optical diffraction component at a second angle of incidence in a second polarization state different from the first polarization state, the first optical diffraction component diffracts the light of the second color with a diffraction efficiency substantially lower than the first diffraction efficiency; when light of a second color in a second polarization state is incident on a color-selective polarizer, the color-selective polarizer rotates the polarization state of the light of the second color from the second polarization state to the first polarization state; when light of a second color is incident on a second optical diffraction component at a second angle of incidence and in a first polarization state, the second optical diffraction component diffracts the light of the second color at a second diffraction angle with a second diffraction efficiency.

[0212] Another aspect of the present disclosure features an optical device comprising: a first optical diffraction component configured to i) diffract light of a first color in a first polarization state incident at a first angle of incidence with a first diffraction efficiency at a first diffraction angle; and ii) diffract light of a second color in a second polarization state incident at a second angle of incidence with a diffraction efficiency substantially lower than the first diffraction efficiency; a color-selective polarizer configured to rotate the polarization state of light of a second color in a second polarization state incident on the color-selective polarizer from a second polarization state to a first polarization state; and a second optical diffraction component configured to diffract light of a second color in a first polarization state incident at a second angle of incidence with a second diffraction efficiency at a second diffraction angle, wherein the color-selective polarizer is located between the first optical diffraction component and the second optical diffraction component.

[0213] In some implementations, the second optical diffraction component is configured to diffract light of a first color in a second polarization state at a first incident angle with a diffraction efficiency substantially lower than that of the second diffraction efficiency.

[0214] In some implementations, the first optical diffraction component, the color-selective polarizer, and the second optical diffraction component are stacked sequentially such that light of the first color and light of the second color are incident on the first optical diffraction component before the second optical diffraction component.

[0215] In some implementations, the optical device further includes a third optical diffraction component and a second color-selective polarizer between the second and third optical diffraction components. The second color-selective polarizer is configured to rotate the polarization state of light of a third color from a second polarization state to a first polarization state when light of a third color is incident on the second color-selective polarizer in a second polarization state. The third optical diffraction component is configured to diffract light of a third color at a third diffraction angle with a third diffraction efficiency when light of a third color is incident on the third optical diffraction component at a third incidence angle and in a first polarization state.

[0216] In some implementations, a color-selective polarizer is configured to rotate the polarization state of light of a first color from a first polarization state to a second polarization state, and a second color-selective polarizer is configured to rotate the polarization state of light of a second color from a first polarization state to a second polarization state without rotating the polarization state of light of the first color.

[0217] In some implementations, the system further includes a third color-selective polarizer configured to rotate the polarization states of the first and second colored light, respectively, from a second polarization state to a first polarization state, without rotating the polarization state of the third color of light. The third optical diffraction component lies between the second and third color-selective polarizers.

[0218] In some implementations, the third optical diffraction component is configured to diffract each of the first and second colored light incident in a second polarization state with a diffraction efficiency substantially lower than that of the third diffraction efficiency. The first optical diffraction component is configured to diffract the third colored light incident in a second diffraction state with a diffraction efficiency substantially lower than that of the first diffraction efficiency, and the second optical diffraction component is configured to diffract each of the first and third colored light incident in a second polarization state with a diffraction efficiency substantially lower than that of the second diffraction efficiency.

[0219] In some implementations, the second color-selective polarizer includes a pair of first and second sub-polarizers. The first sub-polarizer is configured to rotate the polarization state of the second color light from a first polarization state to a second polarization state without rotating the polarization states of the first and third color light respectively, and the second sub-polarizer is configured to rotate the polarization state of the third color light from a second polarization state to a first polarization state without rotating the polarization states of the first and second color light respectively.

[0220] In some implementations, the optical device further comprises a fourth color-selective polarizer configured to rotate the polarization state of a first color of light from a second polarization state to a first polarization state without rotating the polarization states of the second and third color of light respectively, wherein the first optical diffraction component is located between the fourth color-selective polarizer and the color-selective polarizer.

[0221] In some implementations, each of the first, second, and third optical diffraction components includes a holographic grating formed on a recording medium. The recording medium may contain a photosensitive polymer. The recording medium may be optically transparent. Each holographic grating can be fixed to the recording medium.

[0222] In some implementations, each of the first, second, and third optical diffraction components includes a carrier film attached to the recording medium side. Each of the first, second, and third optical diffraction components may include a diffraction substrate attached to the other side of the recording medium opposite to the carrier film.

[0223] In some cases, the carrier film of the first optical diffraction component is attached to the first side of the color-selective polarizer, the diffraction substrate of the second optical diffraction component is attached to the second opposite side of the color-selective polarizer, the carrier film of the second optical diffraction component is attached to the first side of the second color-selective polarizer, and the diffraction substrate of the second optical diffraction component is attached to the second opposite side of the second color-selective polarizer.

[0224] In some implementations, the optical device further includes a substrate, and the first optical diffraction component is located between the substrate and a color-selective polarizer. In some implementations, the optical device further includes an anti-reflective coating on the surface of the substrate. In some implementations, the optical device includes a front and a back surface, with light of a first color and light of a second color incident on the front surface, and the optical device further includes an anti-reflective coating on the back surface.

[0225] In some implementations, the optical device includes a plurality of optical components, including a first optical diffraction component, a color-selective polarizer, and a second optical diffraction component, wherein two adjacent optical components among the plurality of components are mounted together through a refractive index matching material.

[0226] In some implementations, each of the first and second optical diffraction components includes a Bragg grating formed in the recording medium, each Bragg grating having a plurality of fringe planes with a fringe inclination angle θ perpendicular to the fringe planes in the volume of the recording medium. t and includes a plurality of fringe planes having a fringe spacing Λ.

[0227] In some cases, each Bragg grating has a diffraction angle θ when the angle of incidence to the recording medium is the on-Bragg angle. m but,

number

[0228] In some cases, the first and second angles of incidence are substantially identical to the Ombragg angle, and the first and second angles of diffraction are substantially identical to the first Bragg angle.

[0229] In some cases, the fringe tilt angle of each Bragg grid is substantially the same as 45 degrees.

[0230] In some cases, the thickness of the recording medium is more than an order of magnitude larger than the fringe spacing. The thickness of the recording medium can be approximately 30 times greater than the fringe spacing.

[0231] In some cases, the first diffraction angle and the second diffraction angle are substantially identical to each other.

[0232] In some cases, the first and second diffraction angles are in the range of -10 to 10 degrees. The first and second diffraction angles may be substantially identical to 0 degrees. The first and second diffraction angles may be in the range of -7 to 7 degrees. The first and second diffraction angles may be substantially identical to 6 degrees.

[0233] In some cases, each of the first incident angle and the second incident angle is in the range of 70 degrees to 90 degrees. The first incident angle and the second incident angle may be substantially the same as each other.

[0234] In some cases, the first polarization state is s-polarization, and the second polarization state is p-polarization.

[0235] In some implementation modes, the first optical diffraction component is configured to diffract light of a second color incident in the second polarization state with a diffraction efficiency at least one order of magnitude smaller than the first diffraction efficiency.

[0236] In some implementation modes, the color-selective polarizer is configured not to rotate the polarization state of the light of the first color.

[0237] In some implementation modes, the optical device is a second color-selective polarizer configured to rotate the polarization state of the light of the first color from the second polarization state to the first polarization state without rotation of the polarization state of the light of the second color, and the first optical diffraction component is between the second color-selective polarizer and the color-selective polarizer, and further includes the second color-selective polarizer.

[0238] In some implementation modes, the first optical diffraction component includes a first diffraction structure, the second optical diffraction component includes a second diffraction structure, the optical device includes a first reflective layer and a second reflective layer, and the first reflective layer is between the first diffraction structure and the second diffraction structure, the second diffraction structure is between the first reflective layer and the second reflective layer, and the first diffraction structure is i) The first diffraction structure is configured to diffract primary and zero-order first-color light incident at a first incidence angle, wherein the primary light is diffracted at the first diffraction angle and the zero-order light is transmitted at the first incidence angle; and ii) The first diffraction structure is configured to transmit second-color light incident at a second incidence angle. The first reflective layer is configured to i) completely reflect first-color light incident at a first incidence angle and ii) transmit second-color light incident at a second incidence angle. The second diffraction structure is configured to diffract primary and zero-order second-color light incident at a second incidence angle, wherein the primary light is diffracted at the second diffraction angle and the zero-order light is transmitted at the second incidence angle. The second reflective layer is configured to completely reflect second-color light incident at a second incidence angle.

[0239] Another aspect of the present disclosure features an optical device comprising a first optical diffraction component including a first diffraction structure, a second optical diffraction component including a second diffraction structure, a first reflective layer, and a second reflective layer. The first reflective layer is located between the first diffraction structure and the second diffraction structure, and the second diffraction structure is located between the first reflective layer and the second reflective layer. When light of a first color is incident on the first diffraction structure at a first angle of incidence, the first diffraction structure diffracts first-order and zero-order light of the first color, the first diffracting structure diffracts the first-order and zero-order light of the first color, the first diffracting structure diffracts the first-order light at a first angle of incidence, the first diffracting structure diffracts the second-order light at a second angle of incidence, and the first reflective layer diffracts the first-order light at a first angle of incidence. When light is incident on the first reflective layer, the first reflective layer completely reflects the light of the first color. When light of the second color is incident on the first reflective layer at a second angle of incidence, the reflective layer transmits the light of the second color at a second angle of incidence. When light of the second color is incident on the second diffracted structure at a second angle of incidence, the second diffracted structure diffracts the primary and zeroth order light of the second color, with the primary being diffracted at a second diffraction angle and the zeroth being transmitted at a second angle of incidence. When light of the second color is incident on the second reflective layer at a second angle of incidence, the second reflective layer completely reflects the light of the second color.

[0240] Another aspect of the present disclosure is a first optical diffraction component comprising a first diffraction structure configured to i) diffract primary and zero-order light of a first color incident on the first diffraction structure at a first angle of incidence, wherein the primary light is diffracted at the first angle of incidence and the zero-order light is transmitted at the first angle of incidence; and ii) transmit second color light incident on the first diffraction structure at a second angle of incidence; and configured to i) completely reflect first color light incident on a first reflective layer at a first angle of incidence; and ii) transmit second color light incident on the first reflective layer at a second angle of incidence. The optical device is characterized by comprising: a first reflective layer; a second diffraction structure, a second optical diffraction component including a second diffraction structure configured to diffract primary and zero-order second color light incident on the second diffraction structure at a second incidence angle, wherein the primary light is diffracted at a second diffraction angle and the zero-order light is transmitted at a second incidence angle; and a second reflective layer configured to completely reflect second color light incident on the second reflective layer at a second incidence angle, wherein the first reflective layer is located between the first diffraction structure and the second diffraction structure, and the second diffraction structure is located between the first reflective layer and the second reflective layer.

[0241] Another aspect of the present disclosure features an optical device comprising: a first optical diffraction component including a first diffraction structure configured to diffract light of a first color having a first angle of incidence at a first diffraction angle; a second optical diffraction component including a second diffraction structure configured to diffract light of a second color having a second angle of incidence at a second diffraction angle; a first reflective layer configured to completely reflect light of a first color having a first angle of incidence and to transmit light of a second color having a second angle of incidence; and a second reflective layer configured to completely reflect light of a second color having a second angle of incidence, wherein the first reflective layer is located between the first diffraction structure and the second diffraction structure, and the second diffraction structure is located between the first reflective layer and the second reflective layer.

[0242] In some implementations, the optical device further includes a color-selective polarizer between a first diffracting structure and a second diffracting structure. The first diffracting structure i) diffracts light of a first color in a first polarization state incident at a first angle of incidence with a first diffraction efficiency, and ii) diffracts light of a second color in a second polarization state incident at a second angle of incidence. It can be configured to diffract at a diffraction efficiency substantially lower than the first diffraction efficiency. The color-selective polarizer is The polarization state of the second color of light in the second polarization state incident on a color-selective polarizer is defined as follows: The system can be configured to rotate from a second polarization state to a first polarization state. The second diffraction structure can be configured to diffract light of a second color in the first polarization state, incident at a second incidence angle, with a second diffraction efficiency.

[0243] In some implementations, the optical device further includes a side, and a light absorber mounted on the side and configured to absorb fully reflected light of a first color and a second color.

[0244] In some implementations, the first reflective layer is configured to have a lower refractive index than the layer of the first optical diffraction component directly adjacent to the first reflective layer, so that light of a first color with a first angle of incidence is completely reflected by the interface between the first reflective layer and the layer of the first optical diffraction component without completely reflecting light of a second color with a second angle of incidence.

[0245] In some implementations, the first optical diffraction component includes a first carrier film and a first diffraction substrate attached to both sides of the first diffraction structure, wherein the first carrier film is closer to the second diffraction structure than the first diffraction substrate, and the first carrier film may include a first reflective layer.

[0246] In some implementations, the second optical diffraction component includes a second carrier film and a second diffraction substrate attached to both sides of the second diffraction structure, wherein the second diffraction substrate is closer to the first diffraction structure than the second carrier film, and the second reflective layer is attached to the second carrier film.

[0247] In some implementations, the optical device further includes a third optical diffraction component comprising a third diffraction structure configured to diffract primary and zero-order light of a third color incident at a third incidence angle to the third diffraction structure, wherein the primary light is diffracted at the third diffraction angle and the zero-order light is transmitted at the third incidence angle, and a second reflective layer is located between the second diffraction structure and the third diffraction structure.

[0248] In some cases, the first and second reflective layers are configured to transmit light of a third color incident at a third angle of incidence.

[0249] In some implementations, the optical device further includes a third reflective layer configured to completely reflect light of a third color incident at a third angle of incidence to the third reflective layer. A third diffraction structure exists between the second and third reflective layers.

[0250] In some implementations, the second optical diffraction component includes a second diffraction substrate and a second carrier film positioned on both sides of the second diffraction structure, the third optical diffraction component includes a third carrier film and a third diffraction substrate positioned on both sides of the third diffraction structure, and the second reflective layer is located between the second carrier film and the third carrier film.

[0251] In some implementations, each of the first and second diffraction structures includes a holographic grating formed on the recording medium. The recording medium may contain a photosensitive polymer. The recording medium may be optically transparent.

[0252] In some implementations, each of the first and second optical diffraction components includes a respective Bragg grating formed in a recording medium, and each Bragg grating includes a plurality of fringe planes perpendicular to the fringe plane within the volume of the recording medium and having a fringe tilt angle θ t and a fringe spacing Λ.

[0253] In some implementations, each Bragg grating is configured to satisfy Bragg's equation such that when the angle of incidence on the recording medium is the Bragg angle, each diffraction angle θ m is

Equation

[0254] Each of the first and second angles of incidence can be substantially the same as the respective Bragg angle, and each of the first and second diffraction angles can be substantially the same as the respective first-order Bragg angle.

[0255] In some implementations, the thickness of the recording medium is at least one order of magnitude greater than the fringe spacing. The thickness of the recording medium can be about 30 times greater than the fringe spacing.

[0256] In some cases, the first and second diffraction angles are substantially the same as each other. In some examples, each of the first and second diffraction angles is in the range of -10 degrees to 10 degrees. In some examples, each of the first and second diffraction angles is substantially the same as 0 degrees. In some examples, each of the first and second diffraction angles is substantially the same as 6 degrees.

[0257] In some cases, the first angle of incidence is different from the second angle of incidence. In some cases, the light of the first color has a smaller (or shorter) wavelength than the light of the second color, and the first angle of incidence of the light of the first color is larger (or longer) than the second angle of incidence of the light of the second color. In some cases, both the first and second angles of incidence are in the range of 70 to 90 degrees.

[0258] In some implementations, the optical device includes a plurality of components, including a first optical diffraction component and a second optical diffraction component, wherein two adjacent components of the plurality of components are joined together by an intermediate layer comprising at least one of a refractive index matching material, OCA, UV-curable optical adhesive or thermosetting optical adhesive, or optical contact material.

[0259] In some implementations, the second reflective layer includes an intermediate layer.

[0260] In some implementations, the optical device further includes a substrate having a back surface attached to the front surface of a first optical diffraction component. The substrate may include sides angled with respect to the back surface and configured to receive light of multiple different colors at the sides. The angle between the sides and the back surface of the substrate may be 90 degrees or more. The substrate may be configured so that light of multiple different colors is incident on the sides at an incident angle substantially the same as 0 degrees. In some cases, the substrate is wedge-shaped and includes an inclined front surface, and the angle between the front surface and the sides is less than 90 degrees.

[0261] Another aspect of the present disclosure features a system comprising an irradiator configured to provide light of multiple different colors, and one of the optical devices described herein. The optical device is positioned adjacent to the irradiator and is configured to receive light of multiple different colors from the irradiator and to diffract the light of multiple different colors.

[0262] In some implementations, the optical device is configured to diffract light of multiple different colors at diffraction angles that are substantially identical to each other.

[0263] In some examples, each of the diffraction angles falls within the range of -10 to 10 degrees.

[0264] In some implementations, the system further includes a controller coupled to the irradiator and configured to control the irradiator to provide each of several different colors.

[0265] In some implementations, the system further includes a display comprising multiple display elements, and the optical device is configured to diffract light of multiple colors toward the display.

[0266] In some implementations, the controller is coupled to the display and configured to transmit respective control signals to each of the multiple display elements for modulation of at least one characteristic of the display elements.

[0267] In some implementations, the controller is configured to acquire graphic data containing primitive data for multiple primitives corresponding to objects in three-dimensional space, determine the electromagnetic (EM) field contribution of each of the multiple primitives to each of the multiple display elements of the display, generate the sum of the EM field contributions from the multiple primitives to each of the multiple display elements, and generate a control signal for each of the multiple display elements based on the sum of the EM field contributions to the display element.

[0268] Another aspect of the present disclosure is a system comprising a display having a plurality of display elements and one of the optical devices described herein, wherein the optical device is configured to diffract a plurality of different colors of light toward the display.

[0269] In some implementations, the optical device and the display are arranged along a certain direction. The optical device includes a front and a back along the direction, and the display includes a front and a back along the direction, with the front of the display spaced apart from the back of the optical device.

[0270] In some implementations, the front of the display is separated from the back of the optical device by a gap. At least one of the front of the display or the back of the optical device can be treated with an anti-reflective coating.

[0271] In some implementations, the system further includes a transparent protective layer on the back of the optical device.

[0272] In some implementations, the front of the display and the back of the optical device are joined together by an intermediate layer. The intermediate layer may be configured to have a refractive index lower than that of the optical device layer, such that each of the multiple colors of light transmitted in zero order by the optical device is completely reflected at the interface between the intermediate layer and the optical device layer.

[0273] In some implementations, the system further includes a cover (e.g., cover glass) on the front of the display, and the optical device is formed within the cover glass.

[0274] In some implementations, the optical device is configured to receive light of multiple colors at the front of the optical device.

[0275] In some implementations, the optical device includes a substrate in front of the optical device and is configured to receive light of multiple colors on the side of the substrate which is angled relative to the back surface of the substrate.

[0276] In some implementations, the optical device includes at least one diffraction grating supported by a substrate and configured to diffract light of multiple different colors toward a display.

[0277] In some implementations, the substrate includes a container filled with a liquid having a refractive index smaller than that of the diffraction grating recording medium.

[0278] In some mounting configurations, the substrate is wedge-shaped and has a slanted front. The angle between the front and the side may be less than 90 degrees.

[0279] In some implementations, the optical device is configured to receive multiple different portions of light of different colors along different optical paths within a substrate, and to diffract these different portions to illuminate different corresponding areas of a display. These different areas may include two or more of the lower, upper, left, and right areas of the display. The multiple different portions of light of different colors can be provided by different corresponding illuminators. The optical device may be configured to receive multiple different portions of light of different colors from different corresponding sides of the substrate.

[0280] In some examples, the optical device is configured to receive a first portion of light of multiple different colors from a first side of the substrate to the back of the optical device, diffract the first portion to illuminate a first area of ​​the display, and receive a second portion of light of multiple different colors from a second side of the substrate to the front of the optical device, reflect the second portion backward against the back of the optical device, diffract the second portion to illuminate a second area of ​​the display. The first and second sides may be the same side. The second portion of light of multiple different colors may be reflected by total internal reflection or a reflection grating within the optical device. The substrate may also include a partially reflective surface configured to separate the input light into a first portion and a second portion.

[0281] In some implementations, the optical device includes at least one diffraction grating located on the back of the optical device. The diffraction grating may include different sub-regions having different corresponding diffraction efficiencies. The diffraction grating can be configured to diffract a first portion of multiple different colored light incident on a first sub-region of the diffraction grating to illuminate a first region of the display, and to reflect a second portion of multiple different colored light, which is reflected backward from the back of the optical device and incident on a second sub-region of the diffraction grating, to the front of the optical device, and to diffract the second portion to illuminate a second different region of the display.

[0282] In some examples, the diffraction grating is configured such that the first and second diffracted portions on the first and second regions of the display have substantially the same optical power. The first and second regions of the display may have different reflectances associated with the first and second different diffraction efficiencies of the first and second subregions of the diffraction grating.

[0283] In some implementations, the diffraction grating includes multiple sub-regions that are tiled together. These sub-regions can be tiled along the horizontal direction.

[0284] In some cases, the edges of different subregions are configured to contact each other in an optically seamless manner. Different subregions can be formed by including one or more edge-defining elements in at least one optical path of the recording beam or object beam when recording each subregion to the recording medium, and one or more edge-defining elements may include square apertures, rectangular apertures, or planar tile apertures.

[0285] In some cases, two adjacent sub-regions of the diffraction grating are in contact with the gap. The display may include multiple tiled display devices, and the gap between adjacent sub-regions of the diffraction grating is aligned with the gap between adjacent tiled display devices of the display.

[0286] In some cases, two adjacent and distinct subregions have an overlap.

[0287] In some implementations, the diffraction grating is mechanically formed by using embossed structures, nanoimprinted structures, or self-assembled structures.

[0288] In some implementations, the display has a width along the horizontal direction and a height along the vertical direction, both of which are perpendicular to the direction, and the aspect ratio of width to height can be greater than 16:9.

[0289] In some implementations, the optical device is configured to diffract light of multiple different colors at diffraction angles that are substantially identical to each other. In some examples, each of the diffraction angles is in the range of -10 to 10 degrees.

[0290] In some implementations, the display is configured to diffract the diffracted color light backward through an optical device.

[0291] In some implementations, an area of ​​the optical device covers an area of ​​the display.

[0292] In some implementations, the system further includes an irradiator positioned adjacent to the optical device and configured to provide the optical device with light of multiple colors. The irradiator may include multiple light-emitting elements, each configured to emit light of a different color.

[0293] In some implementations, the centers of beams from multiple light-emitting elements may be offset from one another. The irradiator may be configured to provide a light beam having an elliptical or rectangular beam profile. The irradiator may be configured to provide a light beam with a specific polarization orientation. The irradiator may include one or more optical components configured to independently control the ellipticity and polarization orientation of each of several different colors of light.

[0294] In some implementations, the irradiator includes one or more optical components configured to control the uniformity of multiple different colored lights. These one or more optical components include an apodizing optical element or a profile converter.

[0295] In some implementations, the system includes one or more anamorphic optical elements or one or more cylindrical optical elements configured to increase the width of light of multiple different colors.

[0296] In some implementations, the system may further include a prism element between an irradiator and an optical device, configured to receive light of multiple different colors from the input surface of the prism element, and one or more extension gratings adjacent to the exit surface of the prism element, each of which is configured to extend the beam profile of light of different corresponding colors by a coefficient in at least one dimension.

[0297] In some implementations, the system may further include one or more reflectors downstream of one or more expansion diffraction gratings, each of which is configured to reflect light of a particular color to an optical device. The tilt angle of each of the one or more reflectors may be independently adjustable to ensure uniformity of diffraction from the optical device to the display.

[0298] The system may further include at least one color sensor or luminance sensor configured to detect one or more optical properties of the holographic light field formed by the system, and the tilt angle of one or more reflectors is adjustable based on the detected optical properties of the holographic light field. One or more optical properties may include luminance uniformity, color uniformity, or white point.

[0299] In some implementations, one or more reflectors are adjustable to compensate for changes in the alignment of the system's components.

[0300] In some implementations, the optical distance between one or more reflectors and an optical device is configured such that each of several different colors of light is reflected by the corresponding reflector without transmission through one or more other reflectors.

[0301] In some implementations, one or more reflectors are configured such that the light emitted by each of the one or more reflectors comes from substantially different directions.

[0302] In some implementations, the angle between the prism element and the substrate of the optical device can be adjusted to tilt the position of the holographic light field formed by the system.

[0303] In some implementations, one or more expansion gratings are configured to collimate multiple different colored lights in one or two transverse directions, at least partially.

[0304] In some implementations, the system further includes a controller coupled to the irradiator and configured to control the irradiator to provide each of a plurality of colors of light. The controller may be coupled to a display and configured to transmit respective control signals to each of the plurality of display elements for modulation of at least one characteristic of the display elements.

[0305] In some implementations, the controller is configured to acquire graphic data containing primitive data for multiple primitives corresponding to objects in three-dimensional space, determine the electromagnetic (EM) field contribution of each of the multiple primitives to each of the multiple display elements of the display, generate the sum of the EM field contributions from the multiple primitives to each of the multiple display elements, and generate a control signal for each of the multiple display elements based on the sum of the EM field contributions to the display element.

[0306] In some implementations, the controller is configured to sequentially modulate the display with information associated with multiple colors of light over a series of periods, and to control the irradiator to sequentially emit each of the multiple colors of light to the optical device during each period of the series, such that each of the multiple colors of light is diffracted by the optical device toward the display and reflected by the modulated display elements of the display, forming a three-dimensional light field of each color corresponding to an object within each period.

[0307] In some implementations, the controller is configured to modulate the display such that the three-dimensional light field of each color appears entirely in front of the display, entirely behind the display, or partially in front of and partially behind the display.

[0308] In some cases, the display includes a spatial light modulator (SLM) which includes a digital micromirror device (DMD) or a liquid crystal on silicon (LCOS) device.

[0309] In some implementations, the system further includes an optical polarizer placed between the display and the optical device, the optical polarizer being configured to change the polarization state of several different colored lights.

[0310] In some implementations, the optical device includes an optical diffraction component configured to diffract light including light of a plurality of different colors with respect to a display configured to diffract a portion of the light irradiating the display element.

[0311] In some implementations, the optical device further includes an optical redirect component configured to transmit a portion of the light to form a holographic scene and redirect display zero-order light away from the holographic scene in a three-dimensional (3D) space, where the display zero-order light includes reflected light from the display.

[0312] In some implementations, the optical redirect component includes a plurality of redirect holographic gratings for display zero-order light of a plurality of different colors, and each of the plurality of redirect holographic gratings is configured to diffract the display zero-order light of each color of the plurality of different colors of light in respective directions in 3D space at respective diffraction angles.

[0313] In some implementations, the optical diffraction component is configured to diffract light of a plurality of different colors so that the optical diffraction component redirects the display zero-order light reflected from the display away from the holographic scene and irradiates the display at an angle of approximately 0 o degrees.

[0314] In some implementations, the ratio of the amount of display zero-order light in the holographic scene with suppression of the optical diffraction component and the optical redirect component to the amount of display zero-order light in the holographic scene without suppression is less than 2%.

[0315] In some implementations, the optical redirection component includes a one-dimensional suppression grating, the holographic scene includes a band corresponding to the suppression of zero-order light in the display, and the system can be configured such that the band lies outside the viewer's field of view.

[0316] Another aspect of the present disclosure features a system comprising: a display including a plurality of display elements; an optical device positioned adjacent to the display and configured to diffract light toward the display; and a controller connected to the display and configured to acquire graphic data including primitive data for a plurality of primitives corresponding to objects in three-dimensional space; for each of the plurality of primitives, to determine the EM field contribution of the display to each of the plurality of display elements by calculating the electromagnetic (EM) field propagation from the primitive to the display element in a three-dimensional coordinate system; for each of the plurality of display elements, to generate a sum of the EM field contributions from the plurality of primitives to the display element; and for each of the plurality of display elements, to transmit a respective control signal based on the sum of the EM field contributions to the display element for modulation of at least one characteristic of the display element.

[0317] In some implementations, the optical device may include any one of the optical devices that include at least one color-selective polarizer as described herein.

[0318] In some implementations, the optical device includes one of the optical devices having at least one reflective layer as described herein.

[0319] In some implementations, the optical device includes a holographic grid formed on a recording medium.

[0320] In some implementations, the optical device includes a plurality of holographic gratings formed on a recording medium, each of which is configured to diffract light of a particular color with a particular angle of incidence to a display.

[0321] In some implementations, the optical device is positioned in front of the display, and the display is configured to diffract light through the optical device to form a three-dimensional light field corresponding to an object.

[0322] In some implementations, the system further includes an illuminator positioned adjacent to the optical device and configured to supply light to the optical device.

[0323] In some implementations, the controller is configured to sequentially modulate the display with information associated with multiple colors corresponding to multiple colors of light over a series of periods, and to control the irradiator to sequentially emit each of the multiple colors of light to the optical device during each period of the series of periods, such that each of the multiple colors of light is diffracted toward the display by the optical device and reflected by the modulated display elements of the display to form a three-dimensional light field of each color corresponding to an object within each period.

[0324] Another aspect of this disclosure features a method for fabricating any one of the optical devices described herein.

[0325] Another aspect of the present disclosure features a method for fabricating any one of the optical devices comprising at least one color-selective polarizer, comprising forming a first optical diffraction component, forming a second optical diffraction component, and arranging a color-selective polarizer between the first optical diffraction component and the second optical diffraction component.

[0326] In some implementations, forming a first optical diffraction component includes forming a first diffraction structure on a recording medium.

[0327] In some implementations, forming a first diffraction structure on a recording medium includes recording a first holographic grating on the recording medium by irradiating the recording medium with a first recording object beam at a first recording object angle and a first recording reference beam at a first recording reference angle, wherein the first recording object beam and the first recording reference beam have the same wavelength and the same first polarization state.

[0328] In some examples, the light of the first color is broader than or contains the same wavelength range as the first recording reference beam or the first recording object beam. In some examples, the first recording reference beam corresponds to a color different from the first color of the light of the first color.

[0329] In some examples, the first incident angle of light of the first color is substantially the same as the first recording reference angle, and the first diffraction angle is substantially the same as the first recording object angle.

[0330] In some cases, the first recording reference angle is in the range of 70 to 90 degrees. In some cases, the first recording reference angle is in the range of 80 to 90 degrees. In some cases, the angle of the first recording object is in the range of -10 to 10 degrees. In some cases, the angle of the first recording object is substantially identical to 6 degrees. In some cases, the angle of the first recording object is substantially identical to 0 degrees. In some cases, the sum of the first recording reference angle and the first recording object angle is substantially identical to 90 degrees.

[0331] In some implementations, the thickness of the recording medium is more than an order of magnitude greater than the wavelength of the first recording object beam. The thickness of the recording medium can be approximately 30 times greater than the wavelength of the first recording object beam.

[0332] In some implementations, forming a first diffraction structure on a recording medium includes fixing the first diffraction structure to the recording medium.

[0333] In some implementations, the recording medium is located between the carrier film and the diffractive substrate.

[0334] In some embodiments, the first diffraction angle and the second diffraction angle are substantially identical to each other. In some examples, the first incident angle and the second incident angle are substantially identical to each other.

[0335] In some implementations, arranging a color-selective polarizer between a first optical diffraction component and a second optical diffraction component involves sequentially stacking the first optical diffraction component, the color-selective polarizer, and the second optical diffraction component such that light of a first color and light of a second color are incident on the first optical diffraction component before the second optical diffraction component.

[0336] In some implementations, sequentially stacking a first optical diffraction component, a color-selective polarizer, and a second optical diffraction component includes sequentially arranging the first optical diffraction component, the color-selective polarizer, and the second optical diffraction component on a substrate prior to the first optical diffraction component.

[0337] In some implementations, sequentially stacking a first optical diffraction component, a color-selective polarizer, and a second optical diffraction component includes attaching the color-selective polarizer to the first optical diffraction component through a first intermediate layer, and attaching the second optical diffraction component to the color-selective polarizer through a second intermediate layer, wherein each of the first and second intermediate layers includes a refractive index matching material.

[0338] In some implementations, the method further includes forming a third optical diffraction component configured to diffract light of a third color having a first polarization state and a third incident angle at a third diffraction angle with a third diffraction efficiency, and arranging a second color-selective polarizer between the second optical diffraction component and the third optical diffraction component, wherein the second color-selective polarizer is configured to rotate the polarization state of the light of the third color from a second polarization state to a first polarization state.

[0339] In some implementations, a color-selective polarizer is configured to rotate the polarization state of light of a first color from a first polarization state to a second polarization state, and a second color-selective polarizer is configured to rotate the polarization state of light of a second color from a first polarization state to a second polarization state without rotating the polarization state of light of the first color.

[0340] In some implementations, the method further includes arranging a third color-selective polarizer in continuity with a third optical diffraction component such that the third optical diffraction component is between a second color-selective polarizer and a third color-selective polarizer, wherein the third color-selective polarizer is configured to rotate the polarization states of the first color light and the second color light, respectively, from a second polarization state to a first polarization state without rotating the polarization state of the third color light.

[0341] In some implementations, the method further includes arranging a fourth color-selective polarizer in front of a first optical diffraction component such that the first optical diffraction component is between the fourth color-selective polarizer and the fourth color-selective polarizer, the fourth color-selective polarizer being configured to rotate the polarization state of the first color light from a second polarization state to a first polarization state without rotating the respective polarization states of the second color light and the third color light.

[0342] In some implementations, the first polarization state is s-polarization, and the second polarization state is p-polarization.

[0343] Another aspect of the present disclosure is a method for fabricating any one of optical devices having at least one reflective layer, comprising: forming a first optical diffraction component having a first diffraction structure; forming a second optical diffraction component having a second diffraction structure; and arranging a first reflective layer between the first diffraction structure and the second diffraction structure, wherein the second diffraction structure is continuous with the first diffraction structure along a certain direction; and arranging a second reflective layer continuous with the second diffraction structure along a certain direction.

[0344] In some implementations, the method further includes forming a light absorber on the side of an optical device, the light absorber being configured to absorb fully reflected light of a first color and a second color.

[0345] In some implementations, the first reflective layer is configured to have a lower refractive index than the layer of the first optical diffraction component directly adjacent to the first reflective layer, so that light of a first color with a first angle of incidence is completely reflected by the interface between the first reflective layer and the layer of the first optical diffraction component without completely reflecting light of a second color with a second angle of incidence.

[0346] In some implementations, the method further includes forming a third optical diffraction component, which includes a third diffraction structure configured to diffract light of a third color having a third angle of incidence, and arranging a second reflective layer in a direction continuous with the second diffraction structure, which includes arranging a second reflective layer between the second diffraction structure and the third diffraction structure in a direction. Each of the first and second reflective layers may be configured to transmit light of a third color having a third angle of incidence.

[0347] In some implementations, the method further includes arranging a third reflective layer in a direction adjacent to a third diffracting structure, wherein the third reflective layer is configured to completely reflect light of a third color having a third angle of incidence.

[0348] In some implementations, each of the first optical diffraction component, the second optical diffraction component, and the third optical diffraction component includes its respective carrier film and its respective diffraction substrate, and the first reflective layer includes the first carrier film of the first optical diffraction component. Placing the first reflective layer between the first diffraction structure and the second diffraction structure may include attaching the second diffraction substrate of the second optical diffraction component to the first carrier film of the first optical diffraction component by a first intermediate layer. Placing the second reflective layer between the second diffraction structure and the third diffraction structure along the direction may include attaching the second carrier film of the second optical diffraction component to the third carrier film of the third optical diffraction component by a second intermediate layer. The second reflective layer may include a second intermediate layer. The third reflective layer may be attached to the third diffraction substrate of the third optical diffraction component.

[0349] In some implementations, the method further includes arranging a first optical diffraction component on a substrate that is in front of the first optical diffraction component along a direction, wherein the substrate includes a front and a back surface.

[0350] In some implementations, arranging a first optical diffraction component on a substrate includes attaching the front surface of the first optical diffraction component to the back surface of the substrate through a refractive index matching material.

[0351] In some implementations, the substrate includes sides that are angled relative to the back surface of the substrate, and the substrate is configured to receive light of multiple different colors on its sides. The substrate can be configured so that light of multiple different colors is incident on its sides at an incident angle substantially the same as 0 degrees.

[0352] In some implementations, forming a first optical diffraction component including a first diffraction structure includes forming a first diffraction structure on a recording medium.

[0353] In some implementations, forming a first diffraction structure on a recording medium involves recording a first holographic grating on the recording medium by injecting a first recording object beam at a first recording object angle and a first recording reference beam at a first recording reference angle, wherein the first recording object beam and the first recording reference beam have the same wavelength and the same polarization state.

[0354] In some implementations, the light of the first color is broader than or includes the same wavelength range as the first recording reference beam.

[0355] In some implementations, the first recording reference beam corresponds to a color different from the first color of light of the first color.

[0356] In some implementations, the first incident angle of light of the first color is substantially the same as the first recording reference angle, and the first diffraction angle is substantially the same as the angle of the first recording object.

[0357] In some examples, the first recording reference angle is in the range of 70 to 90 degrees. In some examples, the first recording reference angle is in the range of 70 to 80 degrees. In some examples, the angle of the first recording object is in the range of -10 to 10 degrees.

[0358] In some implementations, the thickness of the recording medium is more than an order of magnitude greater than the wavelength of the first recording object beam. The thickness of the recording medium can be approximately 30 times greater than the wavelength of the first recording object beam.

[0359] In some implementations, forming a first diffraction structure on a recording medium includes fixing the first diffraction structure to the recording medium.

[0360] In some implementations, the first angle of incidence is different from the second angle of incidence. In some examples, the light of the first color has a smaller (or shorter) wavelength than the light of the second color, and the first angle of incidence is larger (or longer) than the second angle of incidence.

[0361] Another aspect of the present disclosure features a method comprising forming one of the optical devices described herein by any one of the methods described above, and arranging the optical device and a display including a plurality of display elements such that the optical device is configured to diffract a plurality of different colors of light toward the display.

[0362] In some implementations, arranging the optical device and the display involves separating the back of the optical device from the front of the display by a gap.

[0363] In some implementations, the method further includes forming an anti-reflective coating on at least one of the front surface of the display or the back surface of the optical device.

[0364] In some implementations, arranging the optical device and the display involves mounting the back of the optical device onto the front of the display via an intermediate layer.

[0365] In some cases, the intermediate layer is configured to have a refractive index lower than that of the optical device layer, such that each of several different colors of light transmitted in zero order by the optical device is completely reflected at the interface between the intermediate layer and the optical device layer.

[0366] In some implementations, the optical device is configured to diffract light of multiple different colors at diffraction angles that are substantially identical to each other.

[0367] In some examples, each of the diffraction angles falls within the range of -10 to 10 degrees.

[0368] In some implementations, the display is configured to diffract the diffracted color light backward through an optical device.

[0369] In some implementations, an area of ​​the optical device covers an area of ​​the display.

[0370] In some implementations, the optical device includes a substrate in front of the optical device and is configured to receive light of multiple different colors on the side of the substrate that is angled relative to the back surface of the substrate.

[0371] Another aspect of the present disclosure features a method comprising using an optical device to convert an incident beam containing light of several different colors into light of individually diffracted colors. The optical device may be any one of the optical devices described herein.

[0372] Another aspect of the present disclosure is a method comprising transmitting at least one timing control signal to an irradiator to activate the irradiator and emit light of multiple different colors to the optical device, wherein the optical device is any one of the optical devices described herein, and transmitting at least one respective control signal to each of the multiple display elements of the display to modulate the display elements, such that the light of multiple different colors is reflected by the modulated display elements to form a multicolor three-dimensional light field corresponding to each control signal.

[0373] In some implementations, the method further includes: obtaining graphic data containing primitive data for each of several primitives corresponding to an object in three-dimensional space; determining the EM field contribution to each of several display elements of a display by calculating the electromagnetic (EM) field propagation from the primitive to the display element in a three-dimensional coordinate system for each of the several primitives; generating the sum of the EM field contributions from the several primitives to the display element for each of the several display elements; and generating each control signal for each of the several display elements based on the sum of the EM field contributions to the display element for modulation of at least one characteristic of the display element, wherein the multicolor three-dimensional light field corresponds to the object.

[0374] In some implementations, the method includes sequentially modulating a display with information associated with a plurality of different colors over a series of periods, and controlling an irradiator to sequentially emit each of the plurality of colors of light into the optical device within each period of the series, such that each of the light of the plurality of different colors is diffracted by the optical device toward the display and reflected by the modulated display elements of the display to form a respective color three-dimensional light field corresponding to an object within each period.

[0375] In some implementations, multiple different colored lights are diffracted by the optical device at substantially the same diffraction angle relative to the display. In some examples, the diffraction angle is in the range of -10 to 10 degrees.

[0376] In some implementations, the irradiator and optical device are configured such that multiple different colored lights are incident on a first optical diffraction component of the optical device at their respective angles of incidence. In some examples, the angles of incidence are different from each other. In some examples, the angles of incidence are substantially the same from each other. In some examples, each of the angles of incidence is in the range of 70 to 90 degrees.

[0377] Another aspect of the present disclosure features an optical device comprising at least two optical diffraction components and at least one color-selective polarizer, wherein the optical device is configured to separate individual lights of different colors while suppressing crosstalk between the different colors when light of different colors is incident upon the optical device.

[0378] In some implementations, the optical device is configured such that when light of different colors is incident on the optical device, each of the optical diffraction components diffracts the light of each of the different colors.

[0379] In some implementations, the optical device is configured such that, in the output light beam diffracted by the optical device, the power of light of a particular color among the different colors is at least an order of magnitude higher than the power of light of one or more other colors among the different colors.

[0380] In some implementations, at least one color-selective polarizer is configured to rotate the polarization state of at least one of the different colors of light such that light of a particular color among the different colors is incident on each of the optical diffraction components in a first polarization state, while light of one or more other colors among the different colors is incident on each of the optical diffraction components in a second polarization state different from the first polarization state.

[0381] Another aspect of the present disclosure features an optical device comprising at least two optical diffraction components and at least one reflective layer, wherein the optical device is configured to separate individual lights of different colors while suppressing crosstalk between the different colors when light of different colors is incident upon the optical device, and the at least one reflective layer is configured for total internal reflection of at least one of the different colors of light.

[0382] In some implementations, the optical device is configured such that the output light beam diffracted by the optical device contains only light of a specific color from among different colors, without crosstalk from one or more other colors.

[0383] In some implementations, at least one reflective layer is configured to completely reflect zero-order light of a particular color among the different colors transmitted by each of the optical diffraction components, while transmitting one or more other colors among the different colors.

[0384] In some implementations, the optical device is configured such that when light of different colors is incident on the optical device, each of the optical diffraction components diffracts the light of each of the different colors.

[0385] Another aspect of the present disclosure features either a display or one of the optical devices described herein, the optical device being configured to diffract light of several different colors toward the display.

[0386] Another aspect of the present disclosure features an irradiator configured to provide light of several different colors, and one of the optical devices described herein, the optical device configured to diffract light of several different colors from the irradiator.

[0387] Another aspect of the present disclosure features a system comprising a display and an optical device including one or more transmission diffracting structures for diffracting light toward the display.

[0388] In some implementations, the display is a reflective display configured to diffract light through an optical device. In some implementations, the system further includes an irradiator configured to supply light to the optical device, the irradiator being positioned in front of the transmission diffraction structure of the optical device.

[0389] In some implementations, the display is a transmissive display configured to diffract light forward through an optical device. In some implementations, the system further includes an irradiator configured to supply light to the optical device, the irradiator being located behind the transmissive diffraction structure of the optical device.

[0390] In some implementations, each of the one or more transmission diffraction structures is configured to diffract each of several different colors.

[0391] In some implementations, the optical device further includes one or more reflection diffraction structures, each of which is configured to diffract one or more transmission diffraction structures and one or more reflection diffraction structures to produce each of several different colors.

[0392] Another aspect of this disclosure features a system comprising a display and an optical device including one or more reflection-diffraction structures for diffracting light toward the display.

[0393] In some implementations, the display is a reflective display configured to diffract light through an optical device. In some implementations, the system further includes an irradiator configured to supply light to the optical device, the irradiator being located behind the reflective-diffractive structure of the optical device.

[0394] In some implementations, the display is a transmissive display configured to diffract light forward through an optical device. In some implementations, the system further includes an irradiator configured to supply light to the optical device, the irradiator being positioned in front of the reflective diffraction structure of the optical device.

[0395] In some implementations, each of the one or more reflection diffraction structures is configured to diffract each of several different colors.

[0396] In some implementations, the optical device further includes one or more transmission diffraction structures, each of which is configured to diffract one or more transmission diffraction structures and one or more reflection diffraction structures to produce one of several different colors.

[0397] Another aspect of the present disclosure features an optical device comprising a plurality of optical diffraction components, each comprising at least one transmission diffraction structure and at least one reflection diffraction structure, wherein the optical device is configured to separate individual lights of different colors while suppressing crosstalk between the different colors when light of different colors is incident upon the optical device.

[0398] In some implementations, the transmission diffraction structure and the reflection diffraction structure are configured to diffract light of different colors.

[0399] In some implementations, the optical device further includes at least one reflective layer configured for total internal reflection of at least one light of a different color.

[0400] In some implementations, the optical device further includes at least one color-selective polarizer configured to rotate the polarization state of light of at least one of the different colors such that light of a particular color among the different colors is incident on each of the optical diffraction components in a first polarization state, while light of one or more other colors among the different colors is incident on each of the optical diffraction components in a second polarization state different from the first polarization state.

[0401] Another aspect of the present disclosure features a system comprising a display and an optical device comprising one of the optical devices described herein, wherein the optical device is configured to diffract light of several different colors toward the display.

[0402] Another aspect of the present disclosure features a system comprising an irradiator configured to provide light of multiple different colors, and an optical device comprising one of the optical devices described herein, wherein the optical device is configured to diffract light of multiple different colors from the irradiator.

[0403] In this disclosure, the term “primitive” refers to a fundamental, indivisible element for input or output within a computing system. The element may be a geometric or graphical element. The term “hologram” refers to a pattern displayed by (or uploaded to) a display, which includes amplitude information, phase information, or any combination thereof, relating to an object. The term “holographic reconstruction” refers to a volume light field (e.g., a holographic light field) from a display when illuminated.

[0404] Details of one or more implementations of the subject matter described herein are given in the accompanying drawings and related descriptions. Other features, embodiments, and advantages of the subject matter will become apparent from the specification, drawings, and claims.

[0405] It should be understood that various implementation configurations can be combined in different ways. For example, features from a particular method, device, or system can be combined with features from other methods, devices, or systems. [Brief explanation of the drawing]

[0406] [Figure 1A] A schematic diagram illustrating an exemplary system including a holographic display is provided. [Figure 1B] A schematic diagram of an exemplary holographic display is provided as an example. [Figure 1C] This document illustrates an exemplary system for 3D displays. [Figure 2] This document illustrates an exemplary configuration for electromagnetic (EM) propagation calculations. [Figure 3A]This illustrates exemplary EM propagation of point primitives to display elements. [Figure 3B] This example illustrates the exemplary EM propagation of line primitives to display elements. [Figure 3C] This example illustrates the symbolic EM propagation of triangular primitives to display elements. [Figure 3D] This document illustrates an exemplary implementation of Maxwell holographic occlusion for a point primitive having a line primitive as an occluder. [Figure 3E] This illustrates an exemplary implementation of Maxwell holographic occlusion for a line primitive that has another line primitive acting as an occluder. [Figure 3F] This document illustrates an exemplary implementation of Maxwell holographic occlusion for a triangle primitive with a line primitive as an occluder. [Figure 3G] This document illustrates an exemplary implementation of Maxwell holographic stitching. [Figure 4] This is an illustrative flowchart of the process for displaying objects in 3D. [Figure 5A] An exemplary system for a 3D display, including a reflective display with front illumination, is illustrated. [Figure 5B] Another exemplary system for a 3D display, including a reflective display with full-surface illumination, is illustrated. [Figure 5C] Another exemplary system for a 3D display, including a transmissive display with back illumination, is illustrated. [Figure 5D] Another exemplary system for a 3D display, including a transmissive display with waveguide irradiation, is illustrated. [Figure 5E] Another exemplary system for a 3D display, including a transmissive display with waveguide irradiation, is illustrated. [Figure 5F]Another exemplary system for a 3D display, including a reflective display with waveguide irradiation, is illustrated. [Figure 5G] Another exemplary system for a 3D display, including a reflective display with waveguide irradiation, is illustrated. [Figure 5H] Another exemplary system for 3D displays is illustrated, including a reflective display with optical diffraction irradiation using a transmission field lattice-based structure. [Figure 5I] Another exemplary system for 3D displays is illustrated, including a reflective display with optical diffraction irradiation using a reflection field grid-based structure. [Figure 5J] Another exemplary system for 3D displays is illustrated, including a transmissive display with optical diffraction irradiation using a reflection field grid-based structure. [Figure 5K] Another exemplary system for 3D displays is illustrated, including a transmissive display with optical diffraction irradiation using a transmission field lattice-based structure. [Figure 6A] An example display having display elements with non-uniform shapes will be illustrated. [Figure 6B] An exemplary display with display elements of different sizes is illustrated. [Figure 7A] This example illustrates how to record a grid onto a recording medium. [Figure 7B] An example of diffracting a regenerated reference beam using the grating shown in Figure 7A is illustrated below. [Figure 7C] This example illustrates how to record grids of different colors onto a recording medium using light of different colors. [Figure 7D] This example illustrates how to record grids of different colors onto a recording medium using light of the same color. [Figure 7E] This example illustrates how different colored gratings can be used to diffract regenerated reference beams of different colors. [Figure 7F] This example illustrates crosstalk between diffracted beams of different colors.

[0407] [Figure 8] This example illustrates how to record a diffraction grating with a large reference angle onto a recording medium. [Figure 9A] An exemplary optical device is illustrated that includes two-color diffraction gratings and corresponding color-selective polarizers for diffracting two colors of light separately. [Figure 9B] An example of how the optical device shown in Figure 9A diffracts two colors of light is illustrated. [Figure 10A] An exemplary optical device is illustrated that includes three-color diffraction gratings and corresponding color-selective polarizers for diffracting three colors of light individually. [Figure 10B] Figure 10A illustrates an example of how the optical device diffracts three colors of light. [Figure 11] An exemplary optical device is illustrated that includes two-color diffraction gratings and corresponding reflective layers for diffracting two colors of light separately. [Figure 12A] An exemplary optical device is illustrated that includes three-color diffraction gratings and corresponding reflective layers for individually diffracting three colors of light. [Figure 12B] Another exemplary optical device is illustrated, which includes a diffraction grating of three colors and a corresponding reflective layer having a wedge-shaped substrate. [Figure 12C] Further exemplary optical devices are illustrated, including diffraction gratings of three colors and corresponding reflective layers having wedge-shaped input surfaces. [Figure 13A] The relationship between diffracted beam power and reflected beam power at different incident angles for blue light (Figure 13A), green light (Figure 13B), and red light (Figure 13C) is illustrated with examples. [Figure 13B] The relationship between diffracted beam power and reflected beam power at different incident angles for blue light (Figure 13A), green light (Figure 13B), and red light (Figure 13C) is illustrated with examples. [Figure 13C] The relationship between diffracted beam power and reflected beam power at different incident angles for blue light (Figure 13A), green light (Figure 13B), and red light (Figure 13C) is illustrated with examples. [Figure 14A]This is a flowchart illustrating an exemplary process for manufacturing an optical device including a holographic grating and a corresponding color-selective polarizer. [Figure 14B] This is a flowchart illustrating an exemplary process for manufacturing an optical device including a holographic grating and a corresponding reflective layer. [Figure 15] An exemplary optical device, including a combination of a transmission diffraction grating and a reflection diffraction grating, is illustrated. [Figure 16] An example of incident light that is diffracted by the display elements of a display and reflected by the gaps between the display elements on the display will be illustrated. [Figure 17A] This section illustrates an example of zero-order optics in a holographic scene displayed on a projection screen. [Figure 17B] This example illustrates the zero-order luminescence of a display within a holographic scene seen by the viewer. [Figure 18] This paper illustrates an example of suppressing zero-order light in a holographic scene displayed on a projection screen by diverging the zero-order light of the display. [Figure 19A] This example illustrates the zero-order illuminance of a display in a holographic scene when the display is illuminated with light incident perpendicularly. [Figure 19B] This example illustrates how, when a display is illuminated with light at a certain angle of incidence, the zeroth-order light from the display can be directed away from the holographic scene, thereby suppressing the zeroth-order light from the display in the holographic scene displayed on the projection screen. [Figure 19C] This example illustrates how, when a display is illuminated with light at a certain angle of incidence, the zeroth-order light of the display can be directed away from the holographic scene, thereby suppressing the zeroth-order light of the display in the holographic scene displayed to the viewer's eye. [Figure 20A] An example of a constructive cone and a reconstructed cone corresponding to a holographic scene on a display in a 3D coordinate system is illustrated. [Figure 20B] An example of adjusting the configuration cone in Figure 20A to construct a hologram corresponding to a holographic scene in a 3D coordinate system is illustrated. [Figure 21] This example illustrates how to couple light to an optical diffraction device via a coupling prism to illuminate a display at an incident angle that suppresses zero-order light in a holographic scene. [Figure 22] This example illustrates how light is coupled to an optical diffraction device via a wedge-shaped substrate to illuminate a display at an incident angle that suppresses zero-order light in a holographic scene. [Figure 23A] This example illustrates how to suppress display-zero-order light in a holographic scene displayed on a projection screen by absorbing the display-zero-order light reflected from the display using a metamaterial layer. [Figure 23B] This example illustrates how a metamaterial layer can block (or absorb) the zero-order display light reflected from the display, thereby suppressing the zero-order display light in the holographic scene displayed to the viewer's eye. [Figure 24] This example illustrates a system that suppresses display zero-order light in a holographic scene by redirecting it away from the holographic scene via an optical redirection structure. [Figure 25A] This example illustrates how to redirect zero-order display light in different directions within space via an optical redirection structure. [Figure 25B] This example illustrates how to redirect zero-order display light in different directions within space via an optical redirection structure. [Figure 25C] This example illustrates how to redirect zero-order display light in different directions within space via an optical redirection structure. [Figure 26A] This example illustrates how zero-order light in a display can be redirected when light is input in different directions in space via an optical redirection structure at different angles of incidence. [Figure 26B] This example illustrates how zero-order light in a display can be redirected when light is input in different directions in space via an optical redirection structure at different angles of incidence. [Figure 26C] This example illustrates how zero-order light in a display can be redirected when light is input in different directions in space via an optical redirection structure at different angles of incidence. [Figure 26D] This example illustrates how zero-order light in a display can be redirected when light is input in different directions in space via an optical redirection structure at different angles of incidence. [Figure 26E] This example illustrates how zero-order light in a display can be redirected when light is input in different directions in space via an optical redirection structure at different angles of incidence. [Figure 27A] This example illustrates how to redirect p-polarized zero-order light from a display to transmit it at the Blue Star angle. [Figure 27B] This example illustrates how to redirect s-polarized zero-order display light using an optical retarder for transmission at the Blue Star angle. [Figure 27C] This example illustrates how to redirect s-polarized zero-order display light using an optical retarder for transmission at the Blue Star angle. [Figure 28] This example illustrates how to redirect the zero-order light from a display to an anisotropic transmitter in order to absorb the zero-order light from the display. [Figure 29] This example illustrates how to redirect the zero-order light from a display so that it is completely reflected. [Figure 30A] This example illustrates redirecting zero-order light from two different colored displays in different directions away from the holographic scene. [Figure 30B] This example illustrates redirecting zero-order light from two different colored displays in different directions away from the holographic scene. [Figure 31A]This example illustrates redirecting three different colored zero-order display luminescences in different directions away from the holographic scene, all within the same plane. [Figure 31B] This example illustrates redirecting three different colored zero-order display luminescences in different directions away from the holographic scene, all within the same plane. [Figure 32] This example illustrates redirecting three different colored zero-order display luminescences in different directions away from a holographic scene in space. [Figure 33] This example illustrates how to redirect three different colored zero-order display luminescences in different directions away from a holographic scene, using a switchable grid for one of the colors. [Figure 34] This is a flowchart illustrating an exemplary process for suppressing zero-order illuminance in a holographic scene. [Figure 35A] This example illustrates a system for displaying reconstructed 3D objects. [Figure 35B] This example illustrates a system for displaying reconstructed 3D objects. [Figure 35C] This example illustrates a system for displaying reconstructed 3D objects. [Figure 36A] Figures 36A to 36C illustrate the propagation of three colors of light within the system, using the same diagrams as those in Figures 35A to 35C. [Figure 36B] Figures 36A to 36C illustrate the propagation of three colors of light within the system, using the same diagrams as those in Figures 35A to 35C. [Figure 36C] Figures 36A to 36C illustrate the propagation of three colors of light within the system, using the same diagrams as those in Figures 35A to 35C.

[0408] Similar reference numbers and names in various drawings illustrate similar elements. [Modes for carrying out the invention]

[0409] Implementations of this disclosure feature a technique for enabling 3D display of complex computer-generated scenes as true holograms. The technique provides a novel and deterministic solution to real-time dynamic computational holography based on Maxwell's equations for electromagnetic fields, which can be represented as Maxwell holography. The computation (or calculation) in Maxwell holography can be represented as Maxwell holographic computation (or Maxwell holographic computation). In embodiments, this disclosure utilizes tools including field theory, topology, analytical continuation, and / or symmetry groups to approach the hologram as a Dirichlet or Cauchy boundary condition problem for a general electric field, which enables solving for the hologram in real time without the limitations of conventional holographic systems. In embodiments, this technique can be used to produce phase-only, amplitude-only, or phase and amplitude holograms using a spatial light modulator (SLM) or any other holographic device.

[0410] Implementations of the present disclosure can provide: 1) a mechanism for approximating holograms as electromagnetic boundary conditions using field theory and contact geometry instead of classical optical systems; 2) derivation and implementation of the electromagnetic boundary condition approach to computational holography into computer code and application programming interfaces (APIs), i.e., implementations of hologram computation as a 2D analysis function on the plane of the hologram and subsequent discretization into parallel algorithms; and / or 3) implementations of full 3D holographic versions of standard computer graphics primitives (e.g., points, lines, triangles, and textured triangles) that enable full compatibility with standard existing computer graphics tools and techniques. These techniques enable devices to display common existing content that has not been specifically created for holography, and at the same time enable existing content creators to create holographic works without needing to learn special techniques or use special tools.

[0411] In particular, the techniques disclosed herein may involve the use of a mathematical formulation (or representation) of light as an electromagnetic (EM) phenomenon instead of the mathematical formulation of classical optical systems commonly used in computational holography, such as the Gercberg-Saxton (GS) algorithm. The mathematical formulation disclosed herein is derived from Maxwell's equations. In embodiments, the techniques disclosed herein include treating a displayed image as an electromagnetic field and treating a hologram as boundary value conditions (e.g., the Dirichlet problem) that generate an electromagnetic field. In addition, the desired image can be constructed using a primitive paradigm ubiquitous in computer graphics, enabling, for example, a technique used to display any 3D image not as a projected image on a 2D screen, but as a holographic reconstruction, e.g., a holographic light field. Compared to depth point cloud techniques that suffer from bandwidth limitations, the techniques circumvent these limitations and can use any suitable type of primitive, such as point primitives, line primitives, or polygonal primitives such as triangle primitives. Furthermore, primitives can be rendered with color information, texture information, and / or shading information. This can help achieve recording and compression schemes for CG holographic content, including holographic video.

[0412] In embodiments, the techniques disclosed herein use Maxwell's equations to compute a generated hologram as a boundary condition problem for modeling an electromagnetic field, which can eliminate dependence on the Fast Fourier Transform (FFT) and its inherent limitations, eliminate dependence on collimated light sources such as lasers or light-emitting diodes (LEDs), and / or eliminate the limitations of previous approaches to computational holography and non-deterministic solutions.

[0413] In embodiments, the techniques disclosed herein can be optimized for computational simplicity and speed through a mathematical optimization process that constrains independent inputs on the surface of the hologram, depending on the parameters of the computer-generated (CG) primitives required to construct the scene. This enables the work to be performed in a highly parallel and highly optimized manner on computing architectures, such as application-specific integrated circuits (ASICs) and multi-core architectures. The process of computing the hologram can be viewed as a single instruction executed on input data in the form of a computer-generated image (CGI) scene, and theoretically can be completed in a single clock cycle per CGI primitive.

[0414] In embodiments, the techniques disclosed herein treat holographic scenes as assemblies of fully 3D holographic primitive apertures that are functionally compatible with standard primitives of conventional 3D graphics used, for example, in video games, movies, television, computer displays, or any other display technology. These techniques can enable efficient implementations of these aperture primitives in hardware and software without the limitations inherent in standard implementations of computational holography. The amplitude and color of the primitives can be calculated automatically. The computational complexity can increase linearly with the number of phase elements n, compared to n^2 or n*log(n) in standard computational holography. The resulting image is fully 3D and not a collection of planar images, and the technique does not require iterative amplitude correction with an unknown number of steps. Furthermore, the generated hologram does not have “conjugate” images that occupy space on the holographic device.

[0415] Because holographic primitives are part of a special collection of mathematical objects, they can be computed relatively simply and relatively quickly, making them uniquely suited to parallel distributed computing approaches. Computability and parallelism enable the interactive computation of large holograms, allowing for the design of theoretically unlimited-size, large-area holographic devices that can function as holographic computer displays, telephone displays, home theaters, and even holographic rooms. Furthermore, holograms can fill large areas with light, rendering large shaded areas in 3D without the limitations associated with conventional holographic computation methods, such as elements appearing as contours instead of solids. Moreover, the relatively simple and relatively fast computation allows for real-time display of holograms at interactive speeds unconstrained by n^2 computational loads and iterative amplitude corrections.

[0416] In embodiments, the technology can achieve natural computability on modern ASICs and multicore architectures and achieve full compatibility with modern graphics hardware, modern graphics software, and / or modern graphics tools and toolchains. For example, these technologies can implement a clear and easy-to-use holographic API, through which high-performance rendering of any CG model can be enabled using conventional 3D content creation tools, such as 3ds Max®, SOLIDWORKS®, Maya®, or Unity. The API can enable developers or users to interact with holographic devices, such as optical modulators or holographic systems. The holographic API can create computer graphics primitives as individual holographic scene primitives, enabling the generation of rich holographic content using general-purpose and specially designed holographic computation hardware. The creation of mathematical and computation architectures can enable holograms to be rendered using tools and technologies used to create conventional 3D content and software applications. The optimization of mathematical and computation architectures can enable high-performance embodiments of conventional graphics and rendering to be displayed as holographic reconstructions.

[0417] The algorithms in the techniques disclosed herein are relatively easy to implement in hardware. This not only enables the computational speed necessary for the high-quality rendering expected by users, but also allows the algorithms to be implemented in relatively simple circuits, such as ASIC gate structures, as part of a holographic device. Thus, bandwidth issues that can plague high-density displays may become irrelevant, as scene computation can be spread across the computing architecture built into the display device (e.g., embedded computation), without the need to be computed remotely and then written to each display element (or display pixel) of the display for each frame of content. It also means that the number of display elements, and therefore the size of the holographic display, cannot be relatively limited by the constraints that severely restrict other techniques.

[0418] The technologies disclosed herein can enable the relatively simple and relatively inexpensive implementation of multiple interactive technologies using structured light in a variety of applications, including, for example, solid-state light detection and ranging (LIDAR) devices, 3D printing and machining, smart illuminators, smart microdisplays, optical switching, optical tweezers, or any other applications requiring structured light. The technologies disclosed herein can also be used in optical simulations, such as lattice simulations.

[0419] Figure 1A illustrates a schematic diagram of an exemplary system 100 for a 3D display. System 100 includes a computing device 102 and a holographic display device (or Maxwell holographic display device) 110. The computing device 102 is configured to prepare data for a list of primitives corresponding to objects, e.g., 3D objects, and to transmit the data to the holographic display device 110 via a wired or wireless connection, e.g., a USB-C connection or any other high-speed serial connection. The holographic display device 110 is configured to calculate electromagnetic (EM) field contributions from the list of primitives to display elements of a display (e.g., a modulator) within the holographic display device 110, to modulate the display elements with a pattern, e.g., a hologram, based on the calculated EM field contributions on the display, and to display, in 3D, an optical field corresponding to the object, e.g., a holographic reconstruction, when illuminated. In this specification, a hologram refers to a pattern displayed on the display that includes amplitude information or phase information, or any combination thereof, relating to an object. Holographic reconstruction refers to the volume light field (e.g., holographic light field) from a display when illuminated.

[0420] The computing device 102 may be any suitable type of device, for example, a desktop computer, a personal computer, a notebook, a tablet computing device, a personal digital assistant (PDA), a network appliance, a smart mobile phone, a smartwatch, a High-Speed ​​General-Purpose Packet Radio Service (EGPRS) mobile phone, a media player, a navigation device, an email device, a game console, or any two or more suitable combinations of these computing devices or other computing devices.

[0421] The computing device 102 includes an operating system (OS) 104 which can include several applications 106 as graphics engines. The applications 106 can process or render a scene, for example, any arbitrary CG model, using standard 3D content creation tools, such as 3ds Max®, SOLIDWORKS®, Maya®, or Unity. A scene can correspond to one or more real or imaginary 3D objects, or representations of objects. The applications 106 can operate in parallel to render the scene and obtain an OS graphics abstraction 101 which can be provided to a graphics processing unit (GPU) 108 for further processing. In some implementations, the OS graphics abstraction 101 is provided to a holographic display device 110 for further processing.

[0422] The GPU 108 may include special electronic circuits designed for rapid operation of computer graphics and image processing. The GPU 108 can process a graphics abstraction 101 of the scene to obtain processed scene data 103, which can be used, for example, to obtain a list 105 of primitives indexed in a specific order. The primitives may include at least one of point primitives, line primitives, or polygon primitives. In some implementations, the GPU 108 includes a video driver configured to generate the processed scene data 103 and the list 105 of primitives.

[0423] In some implementations, the GPU 108 includes a conventional renderer 120, which can render the list of primitives 105 into a list of items to be drawn on a conventional monitor 124, for example, a 2D display screen, using conventional rendering techniques such as culling and clipping. The list of items can be sent to the conventional monitor 124 via a screen buffer 122.

[0424] In some implementations, the GPU 108 includes a holographic renderer 130 for rendering the list of primitives 105 into graphic data to be displayed by a holographic display device 110. The graphic data may include the list of primitives and the corresponding primitive data. For example, the graphic data may include the hexadecimal code for each primitive.

[0425] In some implementations, the GPU 108 includes both a conventional renderer 120 and a holographic renderer 130. In some implementations, the GPU 108 includes a conventional renderer 120, and the holographic display device 110 includes a holographic renderer 130.

[0426] The corresponding primitive data for a primitive may also include color information (e.g., texture color, gradient color, or both), texture information, and / or shading information. Shading information can be obtained by any conventional CGI surface shading method, which involves modulating the color or brightness of the primitive's surface.

[0427] The primitive data of a primitive can include coordinate information of the primitive in a 3D coordinate system, such as the Cartesian XYZ coordinate system, polar coordinate system, cylindrical coordinate system, and spherical coordinate system. As will be discussed in more detail below, display elements within the holographic display device 110 can also have corresponding coordinate information in a 3D coordinate system. A primitive of a coordinate location can represent a 3D object adjacent to the display element, for example, in front of the display element, behind the display element, or spanning the display element.

[0428] As an example, a primitive is a shaded line, for example, a straight line that smoothly changes from one color to another over its span. A primitive requires four elements of data to be rendered: two endpoints and color information (e.g., RGB color values) at each endpoint. Assuming the hexadecimal code of the line is a0 and the line extends from the first endpoint (0.1,0.1,0.1) to the second endpoint (0.2,0.2,0.2) in the 3D coordinate system, the color is 1 / 2 blue, at the first endpoint RGB=(0,0,128), and the color is pure red, at the second endpoint RGB=(255,0,0). The holographic renderer determines the amount and type of data to expect for each primitive. In the case of a line, the primitive data of a shaded line in the primitive stream can be a set of instructions such as the following: 0xa0 / / Hex code for shaded lines 0x3dcccccd / / First vertex (0.1,0.1,0.1) float (single) 0x3dcccccd 0x3dcccccd 0x000080 / / The first vertex color is (0,0,128) 0x3e4ccccd / / Second vertex (0.2,0.2,0.2) float (single) 0x3e4ccccd 0x3e4ccccd 0xff0000 / / The color of the second vertex is (255,0,0)

[0429] The primitive data for the shaded line primitive contains a total of 31 hexadecimal words. This can be a highly efficient method for transmitting complex scenes, and the primitive data can be further compressed. Since each primitive is a deterministic Turing step, no terminator is needed. Unlike conventional models in which line primitives are simply drawn on a 2D display screen, the line primitive data is transmitted to a holographic display device 110 that can compute a hologram and display a corresponding holographic reconstruction that presents lines floating in space.

[0430] In some implementations, the computing device 102 transmits non-primitive-based data, such as recorded optical field video, to the holographic display device 110. The holographic display device 110 can calculate a sequence of holograms and display the video as a sequence of holographic reconstructions in space. In some implementations, the computing device 102 transmits CG holographic content to the holographic display device 110 simultaneously with live holographic content. The holographic display device 110 can also calculate corresponding holograms and display the content as corresponding holographic reconstructions.

[0431] As illustrated in Figure 1A, the holographic display device 110 includes a controller 112 and a display 114. The controller 112 may include several computing units or processing units. In some implementations, the controller 112 includes an ASIC, a field-programmable gate array (FPGA), or a GPU unit, or any combination thereof. In some implementations, the controller 112 includes a holographic renderer 130 for rendering a list of primitives 105 into graphic data computed by the computing units. In some implementations, the controller 112 receives an OS graphics abstraction 101 from the computing device 102 for further processing. The display 114 may include several display elements. In some implementations, the display 114 includes a spatial light modulator (SLM). The SLM may be a phase SLM, an amplitude SLM, or a phase and amplitude SLM. In some examples, the display 114 is a digital micromirror device (DMD) or a liquid crystal on silicon (LCOS) device. In some implementations, the holographic display device 110 includes an irradiator 116 adjacent to the display 114 and configured to emit light toward the display 114. The irradiator 116 may include one or more coherent light sources, e.g., lasers, one or more semi-coherent light sources, e.g., LEDs (light-emitting diodes) or super-light-emitting diodes (SLEDs), one or more non-coherent light sources, or a combination of such light sources.

[0432] Unlike conventional 3D graphics systems that capture a 3D scene and render it to a 2D display device, the holographic display device 110 is configured to generate 3D outputs such as holographic reconstructions 117 in the form of a light field, for example, the light of a 3D volume. In a hologram, each display element can contribute to any part of the holographic reconstruction of the scene. Therefore, for the holographic display device 110, each display element needs to be potentially modulated for every part of the scene, for example, each primitive in the list of primitives generated by the GPU 108, for a complete holographic reproduction of the scene. In some implementations, the modulation of a particular element can be omitted or simplified, for example, based on an acceptable level of precision within the reproduced scene or within some area of ​​the scene.

[0433] In some implementations, the controller 112 is configured to calculate the EM field contribution from each primitive to each display element, e.g., phase, amplitude, or both, and for each display element, to generate a sum of the EM field contributions to the display element from a list of primitives. This can be done by executing all primitives and increasing their contributions to a given display element, or by executing each display element for each primitive, or by a hybrid blend of these two techniques.

[0434] The controller 112 can calculate the EM field contribution from each primitive to each display element based on a predetermined equation for the primitive. Different primitives may have corresponding equations. In some cases, the predetermined equation is an analytical equation, as will be discussed in more detail below in relation to Figures 3A-3C. In some cases, the predetermined equation is determined by solving Maxwell's equations using boundary conditions defined in the display 114. The boundary conditions may include Dirichlet or Cauchy boundary conditions. The display elements can then be modulated based on the sum of the EM field contributions by modulating, for example, at least one of the refractive index, amplitude exponent, birefringence, or delay of the display element.

[0435] If the EM field at each point on the surface that borders the field, for example, the value of the solution to Maxwell's equations, is known, then the exact and unique configuration of the EM field in the volume bounded by the boundary surface can be determined. The list of primitives (or the corresponding holographic reconstruction of the hologram) and the display 114 define a 3D space, and the surface of the display 114 forms a portion of the boundary surface of the 3D space. The boundary conditions of the EM field can be determined by setting EM field states (e.g., phase states or amplitude states or phase and amplitude states) on the surface of the display 114, for example, by irradiating the display surface with light. Due to the time symmetry of Maxwell's equations, the display elements are modulated based on the EM field contribution from the primitives corresponding to the hologram, so that a volume light field corresponding to the hologram can be obtained as a hologram reconstruction.

[0436] For example, a line primitive illuminating in a specific color can be set in front of the display 114. As will be discussed in more detail below with respect to Figure 3B, the analytical formula for the linear aperture can be written as a function in space. The EM field contribution from the line primitive on the interface containing the display 114 can then be determined. If the EM field value corresponding to the calculated EM field contribution is set on the display 114, then, due to the time symmetry of Maxwell's equations, the same linear aperture used in the calculation can appear in a corresponding location, for example, at the coordinate position of the linear primitive in a 3D coordinate system, and in a specific color.

[0437] In some examples, we assume there is a line of light between two points A and B in 3D space, as will be discussed in more detail below with respect to Figure 3B. The light is uniformly illuminated and has an intensity I per line distance l. For every infinitesimal dl along the line from A to B, an amount of light proportional to I*dl is emitted. The infinitesimal dl acts as a delta (point) source, and the EM field contribution from the infinitesimal dl to any point on the interface around the scene corresponding to the list of primitives can be determined. Thus, for any display element of display 114, an analytical formula representing the EM field contribution at the display element from an infinitesimal segment of the line can be determined. A special addition / integral that progresses along the line and increases the EM field contribution of the entire line to the EM field at the display element of the display can be determined as an formula. The values ​​corresponding to the formula can be set at the display element, for example, by modulating the display element and illuminating the display element. Then, with time reversal and correction constants, the line can be created at the same location defined by points A and B in 3D space.

[0438] In some implementations, the controller 112 is coupled to the display 114 via a memory buffer. The controller can generate a control signal for each display element based on the sum of the EM field contributions to each of the display elements. The control signals are used to modulate the display elements based on the sum of the EM field contributions. Each control signal is transmitted to the corresponding display element via the memory buffer.

[0439] In some implementations, the controller 112 is integrated with the display 114 and locally coupled to the display 114. As will be considered in more detail in relation to Figure 1B, the controller 112 may include several computing units, each coupled to one or more respective display elements and configured to transmit its respective control signals to each of the one or more respective display elements. Each computing unit may be configured to perform computations on one or more primitives of a list of primitives. The computing units can operate in parallel.

[0440] In some implementations, the irradiator 116 is coupled to a controller 112 and configured to be turned on / off based on a control signal from the controller 112. For example, the controller 112 can activate and turn on the irradiator 116 in response to the controller 112 completing a calculation, e.g., obtaining the total of all EM field contributions for the display elements. As described above, when the irradiator 116 emits light onto the display 114, the modulated elements of the display propagate the light in different directions to form a volume light field corresponding to a list of primitives corresponding to 3D objects. The resulting volume light field corresponds to a solution to Maxwell's equations with boundary conditions defined by the modulated elements of the display 114.

[0441] In some implementations, the controller 112 is coupled to the irradiator 116 through a memory buffer. The memory buffer can be configured to control the amplitude or brightness of the light-emitting elements in the irradiator. The memory buffer for the irradiator 116 can be smaller in size than the memory buffer for the display 114. Some of the light-emitting elements in the irradiator 116 can be smaller than some of the display elements of the display 114, as long as the light from the light-emitting elements can illuminate substantially the entire surface of the display 114. For example, an irradiator with 64 × 64 OLEDs (organic light-emitting diodes) can be used in a display with 1024 × 1024 elements. The controller 112 can be configured to operate several of the illumination elements of the irradiator 116 simultaneously.

[0442] In some implementations, the irradiator 116 is a monochromatic light source configured to emit substantially monochromatic light, such as red, green, yellow, or blue light. In some implementations, the irradiator 116 includes two or more light-emitting elements, such as lasers or light-emitting diodes (LEDs), each configured to emit light of a different color. For example, the irradiator 116 may include red, green, and blue irradiating elements. To display a full-color 3D object, three or more separate holograms can be calculated for colors including at least red, green, and blue. That is, at least three EM field contributions can be obtained from the corresponding primitives to the display elements. The display elements can be sequentially modulated based on at least three EM field contributions, and the irradiator 116 can be controlled to sequentially turn on at least the red, green, and blue irradiating elements. For example, the controller 112 can transmit a first timing signal to turn on the blue irradiating element and transmit a first control signal corresponding to the blue hologram to display the elements of the display 114. After the blue hologram on display 114 is illuminated with blue light for a first period, the controller 112 can transmit a second timing signal to turn on the green illumination element and transmit a second control signal corresponding to the green hologram to display the elements of display 114. After the green hologram on display 114 is illuminated with green light for a second period, the controller 112 can transmit a third timing signal to turn on the red illumination element and transmit a third control signal corresponding to the red hologram to display the elements of display 114. After the red hologram on display 114 is illuminated with red light for a third period, the controller 112 can repeat the above steps. Depending on the temporal coherence of the visual effect on the viewer's eye, the three colors can be combined in the eye to give a full-color appearance. In some cases, the illuminator 116 is turned off during a state change of the display image (or holographic reconstruction) and turned on when a valid image (or holographic reconstruction) is presented for a certain period of time.This can also rely on the temporal coherence of vision to ensure that the image (or holographic reconstruction) appears stable.

[0443] In some implementations, the display 114 has a resolution small enough to diffract visible light to an order of, for example, 0.5 μm or less. The irradiator 116 may include a single white light source, and the emitted white light can be diffracted to different colors by the display 114 for holographic reconstruction.

[0444] Different configurations for system 100 are possible, as will be discussed in more detail below with respect to Figures 5A-5K. The display 114 may be reflective or transmissive. The display 114 can have various sizes ranging from small (e.g., 1-10 cm on each side) to large (e.g., 100-1000 cm on each side). Illumination from the irradiator 116 may be from the front of the display 114 (e.g., for reflective or semi-transmissive displays) or from the rear of the display 114 (e.g., for transmissive displays). The holographic display device 110 can provide uniform illumination across the display 114. In some implementations, optical waveguides can be used to uniformly illuminate the surface of the display 114, as illustrated in Figures 5D-5G. In some examples, the controller 112, the irradiator 116, and the display 114 can be integrated together as a single unit. The integrated single unit may, for example, include a holographic renderer 130 within the controller 112.

[0445] In some implementations, an optical diffraction device, such as a field grating device or light guide device as illustrated in Figures 5H-5K, can be configured to diffract light from an irradiator 116 onto a display 114, which in turn can diffract the light to the viewer's eye. In some examples, light from the irradiator 116 can be incident on the optical diffraction device from the side at a large angle of incidence so that the irradiator 116 does not obstruct the viewer's view of the display 114. In some examples, the diffracted light from the optical diffraction device can be diffracted to the display at an angle of incidence nearly perpendicular to the display so that the light illuminates the display relatively uniformly and diffracts to the viewer's eye with reduced loss (e.g., minimized).

[0446] Figure 1B illustrates a schematic diagram of an exemplary holographic display device 150. The holographic display device 150 may be similar to the holographic display device 110 in Figure 1A. The holographic display device 150 includes a computing architecture 152 and a display 156. The computing architecture 152 may be similar to the controller 112 in Figure 1A. The computing architecture 152 may include an array of parallel computing cores 154. The computing cores may be connected to adjacent computing cores via a communication connection unit 159, for example, a USB-C connection or any other high-speed serial (or parallel) connection unit. The connection unit 159 may be included in a data distribution network in which scene data 151 (e.g., scene primitives) can be distributed among the computing cores 154.

[0447] The display 156 may be similar to the display 114 in Figure 1A and may include an array of display elements 160 positioned on a backplane 158. The display elements 160 may be located in front of the backplane 158, and the computing core 154 may be located behind the backplane 158. The backplane 158 may be a substrate, such as a wafer. The computing core 154 may be on the same substrate as the display 156, or bonded to the back of the display 156.

[0448] Each computing core 154 can be connected to each tile (or array) of the display element 160. Each computing core 154 can be configured to perform calculations in parallel with one or more other computing cores on each primitive of several primitives in the scene data 151. In some examples, the computing core 154 is configured to calculate the EM field contribution from each of each primitive to each of the display elements 160 and to generate a sum of the EM field contributions from several primitives to each of the tiles of the display element 160. The computing core 154 can receive the calculated EM field contributions from other primitives among several primitives to each of the tiles of the display element 160 from other computing cores in the array of computing cores 154 and generate a sum of EM field contributions based on the received calculated EM field contributions. The computing core 154 can generate control signals for each of the tiles of the display element to modulate at least one characteristic of each of the tiles of the display element 160 based on the sum of the EM field contributions to the display element.

[0449] As described above, the computing architecture 152 can also generate a control signal to the irradiator 162 in response to determining, for example, that the calculation of the sum of the EM field contributions from several primitives to each of the display elements has been completed. The irradiator 162 emits input light 153 to irradiate the modulated display element 160, and the input light 153 is diffracted by the modulated display element 160 to form a volume light field, such as a holographic light field 155, corresponding to the scene data 151.

[0450] As illustrated in Figure 1B, the tiles of the display element 160 can be interconnected to a larger display. Correspondingly, the computing cores 154 can be interconnected for data communication and distribution. Note that the parameter that changes in holographic computation between two given display elements is their physical location. Therefore, the task of computing the hologram can be equally shared between the corresponding computing cores 154, and the entire display 150 can operate at the same speed as a single tile, regardless of the number of tiles.

[0451] Figure 1C illustrates an exemplary system 170 for displaying objects in 3D space. System 170 may include a computing device, e.g., computing device 102 in Figure 1A, and a holographic display device 172, e.g., a holographic display 110 in Figure 1A, or 150 in Figure 1B. A user can operate system 170 using an input device, e.g., a keyboard 174 and / or a mouse 176. For example, a user can create CG models of 2D objects 178 and 3D objects 180 through the computing device. The computing device or holographic display device 172 may include a holographic renderer, e.g., a holographic renderer 130 in Figure 1A, for rendering the CG models and generating corresponding graphic data for the 2D objects 178 and 3D objects 180. The graphic data may include primitive data for each of the primitives corresponding to objects 178 and 180 in a list of primitives.

[0452] The holographic display device 172 may include a controller, for example, controller 112 in Figure 1A or 152 in Figure 1B, and a display 173, for example, display 114 in Figure 1A or 156 in Figure 1B. The controller can calculate the respective sum of the EM field contributions from primitives to each display element of the display 173 and generate a control signal for modulating each display element based on the respective sums of the EM field contributions. The holographic display device 172 may further include an irradiator, for example, irradiator 116 in Figure 1A or irradiator 162 in Figure 1B. The controller can generate timing control signals to operate the irradiator. When light from the irradiator illuminates the surface of the display 173, the modulated display elements can propagate the light in 3D space to form a volume light field corresponding to the holographic reconstruction of the 2D view of object 178 and the holographic reconstruction of the 3D object 180. Therefore, the 2D view of object 178 and the 3D holographic reconstruction of object 180 are displayed as holographic reconstructions floating in 3D space in front of display 173, behind display 173, or spanning across the displays.

[0453] In some implementations, the computing device transmits non-primitive-based data, such as recorded optical field video, to the holographic display device 172. The holographic display device 172 can compute and generate corresponding holograms, such as a series of consecutive holograms, and display them in 3D space as corresponding holographic reconstructions. In some implementations, the computing device transmits CG holographic content to the holographic display device 172 simultaneously with live holographic content. The holographic display device 172 can also compute and generate corresponding holograms and display the content in 3D space as corresponding holographic reconstructions.

[0454] Figure 2 illustrates an exemplary configuration 200 for electromagnetic (EM) field calculations. An LCOS device, including a display 202, e.g., an array of elements 204, and a list of primitives including point primitives 206, is located in 3D space 208. 3D space 208 includes a boundary surface 210. In the 3D coordinate system XYZ, a point primitive 206 has coordinate information (x,y,z). Each display element 204 is on a plane flat with respect to other display elements 204 and has a 2D position (u,v). Display elements 204 also have a location in 3D space. By mathematical point transformation, the 2D position (u,v) can be transferred to six coordinates 250 in the 3D coordinate system. That is, the surface of the display 202 forms a portion of the boundary surface 210. Therefore, the EM field contribution from the list of primitives to the display elements, calculated by defining boundary conditions on the surface of the display 202, represents a portion of the total EM field contribution from the primitives to the display elements. A scaling factor, for example 6, can be multiplied by the sum of the EM field contributions for each display element to obtain a scaled sum of field contributions, and the display elements can then be modulated based on this scaled sum of field contributions.

[0455] Exemplary EM field contributions for primitives Primitives can be used in computer graphics rendering. Each type of primitive in computer graphics corresponds to a discrete mathematical function that defines a single holographic primitive of a graphic element added to a hologram in the formulation of the techniques disclosed herein. Each type of primitive can correspond to an equation for calculating the EM field contribution to the display elements. Primitives can be point primitives, line primitives, or polygonal (e.g., triangle) primitives. As illustrated below, analytical equations can be derived by calculating the EM field propagation from the corresponding primitive to the display elements of the display.

[0456] Figure 3A illustrates exemplary EM propagation from point primitive 304 to element 302 of display 300. In the 3D coordinate system XYZ, we assume that the z coordinate is 0 across display 300, meaning that negative z values ​​are behind display 300 and positive z values ​​are in front of display 300. Point primitive 304 has coordinates (x,y,z) and display element 302 has coordinates (u,v,0). The distance d between point primitive 304 and display element 302 is... uv This can be determined based on those coordinates.

[0457] Point primitive 304 can be considered as a point charge with a time-varying amplitude. According to electromagnetic theory, the electric field E generated by such a point charge is:

number

[0458] Therefore, the electric field E at the display element (u,v) u,v teeth,

number

[0459] As discussed above with respect to Figure 2, the surface of the display 300 forms only a portion of the EM field interface. The scale coefficient S is the electric field E u,v Applied to the scaled electric field E φ (u,v) can be obtained in a display element that adjusts the partial boundary as follows.

number

[0460] Figure 3B illustrates an example of EM propagation from line primitive 306 to display element 302 of display 300 in the 3D coordinate system XYZ. As described above, display element 302 may have coordinates (u,v,0) where z=0. Line primitive 306 has two endpoints P0 with coordinates (x0,y0,z0) and P1 with coordinates (x1,y1,z1). The distance d0 between endpoint P0 and the display element can be determined based on their coordinates. Similarly, the distance d1 between endpoint P1 and the display element can be determined based on their coordinates. 01 It can also be determined, for example, d 01 = d1 - d0.

[0461] As discussed above, line primitives can be treated as superpositions or linear deformations, and the corresponding analytical formula for a line primitive as a linear aperture can be obtained as a dispersed delta function in space. This analytical formula can be a closed equation for a continuous 3D line segment as a hologram.

[0462] Figure 3C illustrates exemplary EM propagation from a triangular primitive 308 to a display element 302 of a display 300 in a 3D coordinate system XYZ. As described above, the display element 302 may have coordinates (u,v,0) where z=0. The triangular primitive 308 has three endpoints, P0(x0,y0,z0), P1(x1,y1,z1), and P2(x2,y2,z2). The distances d0, d1, and d2 between the display element and the endpoints P0, P1, and P2 can be determined based on their respective coordinates.

[0463] Similar to the line primitives in Figure 3B, the triangular primitives can be treated as continuous openings in space, and the analytical formula for the EM field contribution of the triangular primitives to the display element can be obtained by integration. This can be simplified to obtain a formula for efficient calculation.

[0464] Exemplary calculations for primitives As discussed above, a controller, for example, controller 112 in Figure 1A, can calculate the EM field contribution from primitives to display elements based on the analytical formula that can be determined as shown above. As an example, the EM field contribution for a line primitive is calculated as follows.

[0465] Each display element within a display has a physical location in space, and each display element is located on a flat plane with respect to other display elements. Assuming that the display elements and their controllers are laid out in the conventional manner in the display device and memory device, a simple mathematical point transformation can be used to translate the logical location of a given display element to its actual physical location in space, based on the logical memory address of the display element in the processor. Thus, when the logical memory address of a display element is looped over in the processor's logical memory space, the corresponding actual physical location in space across the surface of the display can be identified.

[0466] As an example, if the display has a 5 μm pitch in both x and y directions, each logical address increment can move 5 μm in the x direction, and when the x resolution limit of the display is reached, the next increment moves back to the initial x physical location and increments the y physical location by 5 μm. A third spatial coordinate z can be assumed to be zero across the display surface, meaning that negative z values ​​are behind the display and positive z values ​​are in front of the display.

[0467] To begin the line calculation, we can determine that the types of scaled physical distances between the current display element and each of the two points of the line primitive are d0 and d1. In fact, d0 and d1 can be calculated once per primitive, since any subsequent calculation of distance across the display element is a small perturbation of the initial value. Thus, this calculation is performed in one dimension.

[0468] The exemplary calculation process for each primitive is shown in the following calculation code: DD = f(d1, d0), iscale=SS*COLOR*Alpha1, C1=-2*iscale*sin(DD / 2)*sin(Alpha2)*cos(Alpha3), C2 can include -2 * iscale * sin(DD / 2) * sin(Alpha2) * sin(Alpha4), In the formula, SS, Alpha1, Alpha2, Alpha3, and Alpha4 are pre-calculated constants, COLOR is the RGB color value passed as a primitive, and all values ​​are scalar single-precision floats. Both sine and cosine functions can be retrieved from a table stored in the controller to improve calculation efficiency.

[0469] Next, the results in C1 and C2 can be accumulated, for example, in an accumulator for the display elements for each primitive in each display element, and normalized once at the end of the calculation for the display elements. At this point, as described above, the controller can transmit a first control signal to the display elements to modulate them based on the calculated results, and transmit a second control signal to the illuminator to turn them on to emit light. Thus, the holographic reconstruction (or holographic light field) is visible to the viewer. When illuminated, the modulated display elements can cause the light to generate sharp and continuous color lines in three-dimensional space.

[0470] In some implementations, the computed code may include, for example, a hexadecimal code at the beginning of the code to clear previous accumulations in the accumulator. The computed code may also include, for example, a hexadecimal code at the end of the code to store the accumulator results in their respective memory buffers for each display element. In some implementations, a computing device, for example, computing device 102 in Figure 1A, transmits several background or static primitive hexadecimal codes to a controller at application startup or at intervals that display frames that do not affect the primary display frame rate. The computing device can then transmit one or more combinations of potentially hexadecimal codes, along with other foreground or dynamic primitives, at a much higher rate to a controller that can form corresponding control signals for modulating the display elements of the display.

[0471] The calculation process can be orders of magnitude simpler and faster than the most efficient line drawing routines in conventional 2D display technology. Furthermore, this calculation algorithm scales linearly with several display elements. Therefore, scaling the controller's computing units as a 2D network processing system can keep up with the increasing surface area calculation needs of displays.

[0472] Exemplary calculation implementation A Maxwell holographic controller, for example, controller 112 in Figure 1A, can calculate the EM field contribution from primitives to display elements based on an analytical formula that can be determined as shown above. The controller can be implemented, for example, in an ASIC, FPGA, or GPU, or any combination thereof.

[0473] In modern GPU pipelines, the GPU takes a description of a geometric shape, as well as vertex and fragment shader programs, to generate color and depth pixel outputs on one or more output image surfaces (called rendering targets). The process involves a massive fan-out of information where the geometry is unfolded into shaded fragments, followed by a visibility test to select which of these fragments needs to be worked on. A fragment is a record containing all the information involved in shading its sample points, such as the centroid coordinates of a triangle, interpolated values ​​like color or texture coordinates, surface derivatives, etc. The visibility test is the process of creating these records and then rejecting any records that do not contribute to the final image. Fragments that pass the visibility test can be packed into work groups called wavefronts or warps, which are executed in parallel by the shader engine. These generate output values ​​that are written to memory as pixel values ​​and are ready for display or ready for use as input textures for later rendering passes.

[0474] Maxwell holography can significantly simplify the rendering process. In Maxwell holographic computation, any primitive can contribute to any display element. There is no need to extend geometry to pixels, nor is there a need to apply visibility tests before packing wavefronts. This also eliminates the need for decision-making or communication between Maxwell holographic pipelines, allowing computations to be considered in parallel with several possible solutions, each solution being tailored to speed, cost, size, or energy optimization. The graphics pipeline is significantly shorter, with fewer intermediate steps, no data copying or movement, and fewer decisions to reduce latency between starting drawing and getting the result ready for display. This allows Maxwell holographic rendering to create extremely low-latency displays. As will be discussed below, this allows Maxwell holographic computations to improve accuracy and optimize computation speed, for example, by using fixed-point in the Maxwell holographic pipeline, and by optimizing mathematical functions.

[0475] Use fixed-point numbers When calculating the EM contribution from each primitive for each display element (or "fazel"), the intermediate calculation involves generating very large numbers. These large numbers require special handling because they also need to retain fractional parts during the calculation.

[0476] Floating-point values ​​have the drawback of having the precision closest to the origin (zero on the number line), and as you move away from the origin, you lose one bit of precision for every power of two. For numbers close to the range [-1, 1], the precision of floating-point numbers is exquisite, but when you reach tens of millions of numbers, for example, when a single-precision 32-bit IEEE-754 floating-point value reaches the point where no decimal digits remain, the entire mantissa is used to represent the integer part of the value. However, what Maxwell's holography is particularly interested in preserving is the fractional part of large numbers.

[0477] In some cases, fixed-point numbers are used in Maxwell holographic calculations. Fixed-point representation is a number where the decimal point does not change on a case-by-case basis. By selecting the correct number of bits for the integer and fractional parts of a number, the same number of fractional bits can be obtained regardless of the magnitude of the number. Fixed-point numbers are represented as integers with an implicit scaling factor; for example, 14.375 can be represented as the number 3680 (0000111001100000 binary) in a 16-bit fixed-point value with eight fractional bits. This can also be represented as the fixed-point "unsigned 16.8", or simply u16.8. Negative numbers can have one additional sign bit and are stored in "two-sign" form. In this way, the precision of calculations can be greatly improved.

[0478] Optimization for mathematical functions As shown above, Maxwell holographic computation involves the use of transcendental mathematical functions, such as the sine function, cosine function, and arc tangent function. On a CPU, these functions are implemented as floating-point library functions that can use special CPU instructions, or on a GPU, as floating-point units in the GPU. These functions are written to accept arguments as floating-point numbers, and the results are returned in the same floating-point representation. These functions are accurate when the float is exact, rounded correctly, and are built for the general case to handle all edge cases of the floating-point representation (infinity, NaN, signed zero, and denormalized float).

[0479] In Maxwell holographic computation, floating-point representations do not require the use of denormalized floats for gradual underflow, handling of NaN results from operations such as division by zero, changing floating-point rounding modes, or raising floating-point exceptions to the operating system. All of this makes it possible to simplify (and / or optimize) transcendental mathematical functions, as will be considered below, for example.

[0480] In some cases, it is possible to optimize the function to take arguments in a single fixed-point format and return the values ​​to different levels of precision, e.g., input s28.12 and output s15.14. This can be particularly desirable when calculating sine values ​​of tens of millions, where the input argument can be large, but the output only needs to represent the arctangent, which can take values ​​within the range [-1,1] or any value, although it may return values ​​within the range [-π / 2,π / 2].

[0481] In some cases, depending on the relevant input range, optimizations can be made to freely implement the transcendental function as a fully enumerated lookup table, an interpolated table, a semi-table-based polynomial function, or a semi-table-based fully minimal polynomial. It also allows for the application of special range reduction methods to handle large inputs, which general-purpose GPU pipeline computations can skip for speed.

[0482] In some cases, an alternative optimization can be performed to convert trigonometric calculations from the range [-π, π] to a signed 2 representation in the range [-1, 1], which has the advantage of not requiring the expensive 2π division operation.

[0483] Exemplary Implementation for Occlusion Occlusion is often considered a difficult and important topic in computer graphics, and even more so in computational holography. This is because, at least in some cases, the occlusion problem in projected CGI is static, whereas what is hidden and visible in a holographic system depends on the viewer's location, orientation, and direction. GS holography, or its derivative wave approach, was developed to address holographic occlusion. However, masking or blocking contributions from parts of a scene behind other parts of the scene can be very complex and computationally expensive in the GS methodology.

[0484] In Maxwell holography, the occlusion problem can be handled relatively easily because it is completely deterministic and trivial which display element (e.g., fesel) corresponds to which primitive. For example, whether a given display element contributes to the reconstruction of a given primitive can be determined when the calculation of the given primitive is performed. If, after determining that some display elements do not contribute to a given primitive due to occlusion, the sum of the EM contributions to one of the display elements is calculated, the EM contribution from the given primitive is omitted from the calculation of the sum of the EM contributions to one of the display elements.

[0485] For illustrative purposes only, Figures 3D-3F demonstrate the determination of display elements that do not contribute to a given primitive (the point in Figure 3D, the line in Figure 3E, and the triangle in Figure 3F) using a line primitive as an occluder. The line primitive has a start point O1 and an end point O2.

[0486] As illustrated in Figure 3D, the point primitive P0 is behind the occluder and close to the display. By extending the lines connecting O1-P0 and O2-P0, the range of display elements D1-D2 in the display that do not contribute to the reconstruction of the point primitive P0 is determined.

[0487] In some examples, the coordinate information of O1, O2, and P0, stored in the "Z" buffer calculated by the GPU (e.g., GPU 108 in Figure 1A), is known before the scene is transmitted to the Maxwell Holographic Controller (e.g., Controller 112 in Figure 1A). For example, in the XZ plane at y=0, the coordinate information could be O1(Ox1,Oz1), O2(Ox2,Oz2), and P0(Px,Pz), where Oz1=Oz2=Oz. Based on the coordinate information, the coordinate information of D1 and D2 is: We can determine that Dx1 = Px + ρ(Px - Ox2) and Dx2 = Dx1 + ρ(Ox2 - Ox1) (4), In the equation, ρ = Pz / (Oz - Pz) and Dz1 = Dz2 = 0.

[0488] The information in D1 and D2 can be stored as additional information in the "S" buffer of the Maxwell holographic controller, in addition to the information in the Z buffer of the point primitive P0. In this way, the additional information can be used to trivially mask the contribution of a particular display element (within the range of D1 to D2) to a particular primitive P0 in the indexed primitive list.

[0489] Figure 3E illustrates how to determine how a particular display element contributes to a line primitive that has an occluder in front of (or ahead of) it. By connecting a particular display element D0 to the start point O1 and end point O2 of the occluder, two point primitives P1 and P2 on the line primitive are determined to be intersections. Therefore, the particular display element D0 does not contribute to the reconstruction of the portion of the line primitive from P1 to P2. Consequently, when calculating the total EM contribution to the particular display element D0, the EM contribution from the portion of the line primitive P1-P2 is not calculated.

[0490] This can be implemented in two ways. In the first method, the EM contributions from sub-parts P0-P1 and P2-Pn to a specific display element D0 are summed up as the EM contribution of the line primitive to the specific display element D0 by considering occlusion from occluders. In the second method, the EM contribution from the entire line primitive P0-Pn is calculated together with the EM contribution from sub-parts P1-P2, and the difference between the two calculated EM contributions can be considered as the EM contribution of the line primitive to the specific display element D0 by considering occlusion from occluders. The coordinate information of P1 and P2 or sub-parts P1-P2 can be stored in the Maxwell Holographic Controller's "S" buffer, along with occluder information and other information in the GPU's "Z" buffer, as part of the line primitive that does not contribute to the specific display element D0.

[0491] Figure 3F illustrates how to determine how a particular display element contributes to a triangular primitive that has an occluder in front of it. By connecting a particular display element D0 to the start point O1 and end point O2 of the occluder, the four point primitives P1, P2, P3, and P4 on the sides of the triangular primitive are determined to be intersections. Therefore, the particular display element D0 contributes to points P1, P2, P3, P4, P C It does not contribute to the reconstruction of the triangular primitive portion enclosed by it. Therefore, when calculating the sum of EM contributions to a particular display element D0, the triangular primitive portion P1-P2-P3-P4-P C The EM contribution from is not calculated. That is, by considering the occlusion of the occluder, point P A The first triangle formed by P1 and P2, and point P B Only the EM contribution from the second triangle formed by P3 and P4 is to the triangle primitive P A -P B -P C It is totaled as the EM contribution of P1, P2, P3, and P4 or triangular primitive P A-P1-P2, and P B -The coordinate information of P3-P4, along with occluder information and other information in the GPU's "Z" buffer, contributes to the triangular primitive P of a specific display element D0. A -P B -P C As part of this, it can be stored in the "S" buffer of the Maxwell Holographic Controller.

[0492] The implementation of occlusion in Maxwell holography allows for the conversion of the "Z" buffer in the GPU to the "S" buffer in the Maxwell holographic controller, enabling the masking of the contribution of a particular primitive (or a specific part of a primitive) to a specific display element within an indexed primitive list. This not only provides accurate and physically correct occlusion but also saves computation time by allowing primitives that do not contribute to a given display element to be ignored, and computation to be moved on to the next display element. The "S" buffer can contain additional information related to the diffraction efficiency of the display.

[0493] The "S" buffer can also contain rendering features such as holographic specular highlights where the surface reflectivity depends on the viewing angle. In conventional CGI, specular highlights depend only on the orientation of the rendered object, whereas in the Maxwell holographic context, the direction in which the object is displayed also matters. Therefore, geometric specular information can be encoded in the "S" buffer as an addition (specular) rather than a subtraction (occlusion) contribution. In Maxwell holography, the mathematics of holographic specular highlights can be substantially the same as that of holographic occlusion.

[0494] Exemplary implementation for stitching When light illuminates a display modulated with EM contributions from a list of primitives in a 3D object, the modulated display causes the light to propagate in different directions, forming a volume light field corresponding to the primitives. This volume light field is a Maxwell holographic reconstruction. Two adjacent primitives within a 3D object, for example, two triangle primitives, share a common edge (e.g., a border or surface). During reconstruction, a stitching problem can arise, where the reconstruction of two adjacent primitives can double the light intensity of the common edge. This can affect the appearance of the reconstructed 3D object.

[0495] As illustrated in Figure 3G, to address the stitching problem in Maxwell holography, adjacent primitives can be scaled down by a predetermined coefficient so that gaps can be formed between them. In some cases, instead of scaling down two adjacent primitives, only one primitive or a portion of a primitive is scaled down. For example, the lines of a triangular primitive can be scaled down so that they separate from another triangular primitive. In some cases, scaling can include scaling different parts of a primitive using different predetermined coefficients. The scaling can be designed so that the gaps are large enough to separate adjacent primitives and minimize the stitching problem, and small enough so that the reconstructed 3D object appears seamless. The predetermined coefficients can be determined based on display and viewer information, such as the maximum spatial resolution of the holographic light field, and the minimum distance from the viewer to that portion of the primitive if that portion of the primitive is fully or partially behind the display.

[0496] In some cases, the scaling operation can be applied to primitive data of primitives acquired from a holographic renderer, for example, the holographic renderer 130 in Figure 1A, and the scaled primitive data of the primitives is sent to a Maxwell holographic controller, for example, the controller 112 in Figure 1A. In some cases, the controller can perform the scaling operation on the primitive data acquired from the holographic renderer before calculating the EM contribution of the primitives to the display elements of the display.

[0497] Exemplary implementation for texture mapping Texture mapping is a technique developed in computer graphics. The basic idea is to take a source image and apply it as a decal to the surface of a CGI system, allowing details to be rendered into the scene without the need to add complex geometry. Texture mapping can include techniques for creating realistic illumination and surface effects within a CGI system and can be universally referred to as the application of surface data to a triangular mesh.

[0498] Maxwell holography allows for the rendering of flat, shaded, and interpolated triangular meshes in true 3D using an analytical relationship between any triangle in space and a phase diagram on a holographic device. However, for compatibility with modern rendering engines, the ability to map information on the surface of these triangles is desirable. This presents a practical problem in that the speed of the method is derived from the existence of analytical mapping that does not allow for data-driven amplitude changes.

[0499] The Discrete Cosine Transform (DCT) is an image compression technique that can be thought of as a real-valued version of the Fast Fourier Transform (FFT). The DCT relies on an encoding-decoding process that assigns weights to the cosine harmonics within a given image. The result of encoding is a set of weights equal to the number of pixels in the original image, and no information is lost when reconstructing the image using all the weights. However, for many images, an acceptable reconstruction can be performed using a small subset of weights, allowing for a larger compression ratio.

[0500] The two-dimensional DCT decoding (rendering) process involves a weighted double sum across all DCT weights and all destination pixels. This can be applied to Maxwell holography for texture mapping. In Maxwell holography, triangle rendering involves a "spiked" double integral in phase space to determine the phase contribution of individual Fessels to the triangle in question. The integral is folded into a double sum that mirrors the one in the DCT reconstruction, and then the analytic triangle equation can be re-derived with respect to the DCT weights. This implementation of DCT techniques in Maxwell holographic computation allows for drawing complete texture-mapping triangles, applying image compression to the rendered texture triangle data, and utilizing existing toolsets that automatically compress texture and image data using DCT, such as JPEG.

[0501] In some implementations, to render Maxwell holographic textured triangles, the desired spatial resolution for the mapping on a given surface is first calculated. Next, a texture with resolution is supplied and compressed with angle and origin information to obtain DCTs that are correctly oriented on the triangles. Then, a list of triangle angles and DCT weights is included in an indexed primitive list and sent to the Maxwell holographic controller. The DCT weights can be included in the EM contribution of the triangle primitive to each display element. Textured triangles can be n times slower than flat triangles, where n is the number of (non-zero) DCT weights sent with the primitives. Modern techniques for "fragment shading" can be implemented in Maxwell holographic systems, where the DCT coding step replaces the filtering step for conventional projection rendering.

[0502] As an example,

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[0503] By decoding, the amplitude value A mn teeth,

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[0504] When calculating the EM contribution of a textured triangle primitive to a display element (e.g., a feszel), the corresponding DCT weight A* mn The DCT clause having is

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[0505] Exemplary process Figure 4 is a flowchart of an exemplary process 400 for displaying an object in 3D. Process 400 may be executed by a controller for the display. The controller may be controller 112 in Figure 1A or 152 in Figure 1B. The display may be display 114 in Figure 1A or 156 in Figure 1B.

[0506] Data containing the primitive data for each primitive corresponding to an object in 3D space is obtained (402). The data can be obtained from a computing device, for example, computing device 102 in Figure 1A. The computing device can process the scene to generate primitives corresponding to the objects. The computing device may include a renderer for generating primitive data for the primitives. In some implementations, the controller generates the data itself, for example, by rendering the scene.

[0507] A primitive can include at least one of a point primitive, a line primitive, or a polygon primitive. The list of primitives may be indexed in a specific order, for example, so that an object can be reconstructed. Primitive data may include color information having at least one of a texture color, a gradient color, or a constant color. For example, a line primitive may have at least one of a gradient color, a texture color, or a constant color. A polygon primitive may also have at least one of a gradient color, a texture color, or a constant color. Primitive data may also include texture information for the primitive and / or shading information on one or more surfaces of the primitive (e.g., a triangle). Shading information may include at least one modulation of color or brightness on one or more surfaces of the primitive. Primitive data may also include coordinate information for each of the primitives in a 3D coordinate system.

[0508] A display may include several display elements, and a controller may include several computing units. The coordinate information of each display element in a 3D coordinate system can be determined based on the coordinate information of each primitive in a list of primitives in a 3D coordinate system. For example, the distance between the display and the object corresponding to the primitive can be determined in advance. Based on the given distance and the coordinate information of the primitive, the coordinate information of the display element can be determined. The coordinate information of each display element may correspond to the logical memory address of the element stored in memory. In this way, when the controller loops through the logical memory addresses of the display elements in the controller's logical memory space, it can identify the corresponding actual physical location of the display element in space.

[0509] The EM field contribution from each primitive to each display element is determined by calculating the propagation of the EM field from the primitive to the element in a 3D coordinate system (404). The EM field contribution may include at least one of either a phase contribution or an amplitude contribution.

[0510] As illustrated above with respect to Figures 3A-3C, at least one distance between a primitive and a display element can be determined based on the coordinate information of each display element and the coordinate information of each primitive. In some cases, for each primitive, at least one distance may be calculated or determined only once. For example, a controller may determine a first distance between a first primitive and a first element of a display element based on the coordinate information of each first primitive and the coordinate information of each first element, and determine a second distance between a first primitive and a second element based on the first distance and the distance between the first and second elements. The distance between the first and second elements may be predetermined based on the pitch of multiple elements of the display.

[0511] The controller can determine the EM field contribution from the primitive to the display element based on a predetermined equation for the primitive and at least one distance. In some cases, as illustrated above with respect to Figures 3A-3C, the predetermined equation can be determined by analytically calculating the EM field propagation from the primitive to the element. In some cases, the predetermined equation can be determined by solving Maxwell's equations. In particular, Maxwell's equations can be solved by providing boundary conditions defined on the surface of the display. The boundary conditions can include Dirichlet or Cauchy boundary conditions. The primitive and the display element are in 3D space, and the surface of the display forms part of the interface of 3D space. The predetermined equation can include at least one of the functions, including sine, cosine, and exponential functions. During the calculation, the controller can identify at least one value of the function in a table stored in memory, which can improve the calculation speed. The controller can determine the EM field contribution of each primitive to each display element by determining the first EM field contribution from the first primitive to the display element in parallel with determining the second EM field contribution from the second primitive to the display element.

[0512] For each display element, the sum of the EM field contributions to the display element is generated from the list of primitives (406).

[0513] In some implementations, the controller determines the first EM field contribution from the primitive to the first display element, sums the first EM field contributions for the first element, determines the second EM field contribution from the primitive to the second display element, and sums the second EM field contributions for the second display element. The controller may include several computing units. The controller may determine the EM field contribution from the first primitive to the first element by the first computing unit in parallel with the second computing unit determining the EM field contribution from the second primitive to the first element.

[0514] In some implementations, the controller determines the first EM field contribution from the first primitive to each of the display elements, and determines the second EM field contribution from the second primitive to each of the display elements. The controller then accumulates the EM field contributions for the display elements by adding the second EM field contributions to each of the first EM field contributions for each display element. In particular, the controller can determine the first EM field contribution from the first primitive to each of the display elements by using the first computing unit, in parallel with determining the second EM field contribution from the second primitive to each of the display elements by using the second computing unit.

[0515] A first control signal is transmitted to the display, and the first control signal is for modulating at least one characteristic of each display element based on the sum of the field distributions to the display elements (408). The at least one characteristic of an element includes at least one of refractive index, amplitude exponent, birefringence, or delay.

[0516] The controller can generate a control signal for each display element based on the sum of the EM field contributions from the primitive to the element. Each control signal is intended to modulate at least one characteristic of the element based on the sum of the EM field contributions from the primitive to the element. That is, the first control signal includes the respective control signals for each display element.

[0517] In some examples, displays are controlled by electrical signals. Each control signal can then be an electrical signal. For example, an LCOS display includes an array of microelectrodes, the voltage of which is individually controlled as element intensity. An LCOS display can be filled with a birefringent liquid crystal (LC) mixture that changes its refractive index as the applied voltage changes. Thus, each control signal from the controller can control the relative refractive index across the display elements, and therefore the relative phase of light passing through or reflected by the display.

[0518] As discussed above, the display surface forms part of the interface. The controller can obtain a scaled sum of field contributions by multiplying the sum of each element's field contributions by a scaling factor, and generate the respective control signals based on the scaled sum of field contributions for each element. In some cases, the controller can normalize the sum of field contributions for each element among all elements, for example, and generate the respective control signals based on the normalized sum of field contributions for each element.

[0519] A second control signal is transmitted to the illuminator as a control signal to turn on the illuminator in order to irradiate light onto the modulated display (410). The controller may generate and transmit the second control signal in response to determining the completion of obtaining the sum of the field contributions for each of the display elements. Due to time symmetry (or energy conservation), the modulated elements of the display can propagate light in different directions to form a volume light field corresponding to an object in 3D space. The volume light field can correspond to a solution of Maxwell's equations with boundary conditions defined by the modulated elements of the display.

[0520] In some implementations, the irradiator is coupled to a controller through a memory buffer configured to control the amplitude or brightness of one or more light-emitting elements within the irradiator. The memory buffer for the irradiator may be smaller in size than the memory buffer for the display. Some of the light-emitting elements within the irradiator may be smaller than some of the elements of the display. The controller may be configured to operate one or more of the light-emitting elements of the irradiator simultaneously.

[0521] In some examples, the illuminator includes two or more light-emitting elements, each configured to emit light of a different color. The controller can be configured to control the illuminator to sequentially modulate the display with information associated with a first color during a first period, and to modulate the display with information associated with a second color during a second consecutive period, and to sequentially turn on the first light-emitting element to emit light of the first color during the first period, and the second light-emitting element to emit light of the second color during the second period. In this way, a multicolor object can be displayed in 3D space.

[0522] In some examples, the display has a resolution small enough to diffract light. The irradiator can cause the display to emit white light that diffracts into light of different colors, thereby allowing it to display multicolored objects.

[0523] Exemplary System Figures 5A to 5K show exemplary implementations of systems for 3D displays. Any one of the systems can correspond, for example, to system 100 in Figure 1A. Figures 5A and 5B show exemplary systems having a reflective display with front illumination. Figure 5C shows exemplary systems having a transmissive display with back illumination. Figures 5D and 5E show exemplary systems having a transmissive display with waveguide illumination. Figures 5F and 5G show exemplary systems having a reflective display with waveguide illumination. Figures 5H and 5I show exemplary systems having a reflective display with optical diffraction illumination using a transmissive grating structure (Figure 5H) and a reflective grating structure (Figure 5I). Figures 5J and 5K show exemplary systems having a transmissive display with optical diffraction illumination using a reflective grating structure (Figure 5J) and a transmissive grating structure (Figure 5K).

[0524] Figure 5A illustrates a system 500 with a reflective display having front illumination. The system 500 includes a computer 502, a controller 510 (e.g., an ASIC), a display 512 (e.g., an LCOS device), and an irradiator 514. The computer 502 may be the computing device 102 in Figure 1A, the controller 510 may be the controller 112 in Figure 1A, the display 512 may be the display 114 in Figure 1A, and the irradiator 514 may be the irradiator 116 in Figure 1A.

[0525] As illustrated in Figure 5A, computer 502 includes an application 504 having a renderer 503 for rendering a scene of objects. The rendered scene data is processed by a video driver 505 and then by a GPU 506. The GPU 506 may be the GPU 108 in Figure 1A and can be configured to generate a list of primitives corresponding to the scene and their respective primitive data. For example, the video driver 505 can be configured to process the rendered scene data and generate a list of primitives. As described above, the GPU 506 may include a conventional 2D renderer, for example, the conventional 2D renderer 120 in Figure 1A, for rendering the primitives into a list of items to be drawn on a 2D display 508. The GPU 506 or controller 510 may include a holographic renderer, for example, the holographic renderer 130 in Figure 1A, for rendering the list of primitives into graphic data displayed by the display 512.

[0526] The controller 510 is configured to receive graphic data from the computer 502, calculate the EM field contribution to each element of the display 512 from a list of primitives, and generate the sum of the EM field contributions from the primitives to each element. The controller 510 can generate a control signal for each of the display elements in order to modulate at least one characteristic of the display elements. The controller can transmit the control signals to the display elements of the display 512 through the memory buffer 511 for the display 512.

[0527] The controller 510 can also generate and transmit control signals, such as irradiation timing signals, to operate the irradiator 514. For example, the controller 510 can generate and transmit a control signal in response to determining that the calculation of the total EM field contribution from primitives to display elements is complete. As described above, the controller 510 can transmit control signals to the irradiator 514 via a memory buffer. The memory buffer can be configured to control the amplitude or brightness of the light-emitting elements in the irradiator 514 and to operate the light-emitting elements simultaneously or sequentially.

[0528] As illustrated in Figure 5A, the irradiator 514 can emit a collimated light beam 516 incident on the front of the display 512 at an incident angle in the range of 0 degrees to approximately ±90 degrees. The emitted light beam is diffracted from the display 512 to form a holographic light field 518 corresponding to an object, which can be viewed by the viewer.

[0529] Figure 5B illustrates another system 520, which has another reflective display 524 with front illumination. Compared to system 500 in Figure 5A, system 520 has a larger reflective display 524. To accommodate this, or for other packaging or aesthetic reasons, the display controller 522 is contained in a housing which may be a support or enclosure for the illuminator 526. The controller 522 is similar to the controller 510 in Figure 5A and may be configured to receive graphic data from the computer 521, calculate the EM field contribution from primitives to each of the display elements of the display 524, and generate the respective sums of the EM field contributions from primitives to each of the display elements. The controller 522 then generates a respective control signal for each of the display elements in order to modulate at least one characteristic of the display elements and transmits the respective control signals to the display elements of the display 524 through a memory buffer 523 for the display 524.

[0530] The controller 522 also transmits control signals to the irradiator 526 to activate it. The irradiator 526 emits a divergent or semi-collimated light beam 527 that covers the entire surface of the display 527. The light beam 524 is diffracted by the modulated display 524 to form a holographic light field 528.

[0531] Figure 5C illustrates a system 530 comprising a transmissive display 534 with back illumination. The transmissive display 534 may be, for example, a large display. The system 530 includes a controller 532, which may be similar to the controller 510 in Figure 5A. The controller 532 may be configured to receive graphic data from a computer 531, calculate the EM field contribution from primitives to each of the display elements of the display 534, and generate the sum of the respective EM field contributions from primitives to each of the display elements. The controller 532 then generates a respective control signal for each of the display elements in order to modulate at least one of the characteristics of the display elements and transmits the respective control signals to the display elements of the display 534 through a memory buffer 533 for the display 534.

[0532] The controller 532 also transmits control signals to the irradiator 536 to activate it. Unlike system 500 in Figure 5A and system 520 in Figure 5B, the irradiator 536 in system 530 is positioned behind the back of the display 534. To cover the large surface area of ​​the display 534, the irradiator 536 emits a divergent light beam 535 or a semi-collimated light beam 535 to the back of the display 534. The light beam 535 is transmitted through the modulated display 534 and diffracted to form a holographic light field 538.

[0533] Figure 5D illustrates another system 540, which includes a transmissive display 544 with waveguide irradiation. System 540 also includes a controller 542 and an irradiator 546. The controller 542 may be similar to the controller 510 in Figure 5A and may be configured to receive graphic data from a computer 541, perform calculations on the graphic data, generate control signals for modulation and transmit them to the display 544, and generate and transmit timing signals to activate the irradiator 546.

[0534] The irradiator 546 may include a light source 545 and may include or optically mount a waveguide 547. Light emitted from the light source 545 can be coupled to the waveguide 547, for example, from the side cross section of the waveguide. The waveguide 547 is configured to guide the light so as to uniformly illuminate the surface of the display 544. The light guided by the waveguide 547 enters the back of the display 544, passes through the display 544, and is diffracted by the display 544 to form a holographic light field 548.

[0535] Unlike system 500 in Figure 5A, 520 in Figure 5B, and 530 in Figure 5C, in system 540, the controller 542, display 544, and waveguide 547 are integrated together into a single unit 550. In some cases, the waveguide 547 and light source 545 can be integrated as a planar active waveguide irradiator, which can further increase the degree of integration of the single unit 550. As discussed above, the single unit 550 can be connected or tiled with other similar units 550 to form a larger holographic display device.

[0536] Figure 5E illustrates another system 560, which includes another transmissive display 564 having waveguide irradiation. Compared to system 540, the transmissive display 564 can potentially accommodate a larger display than the transmissive display 544. For example, the transmissive display 564 can have a larger area than the controller 562, and to accommodate this, the controller 562 can be positioned away from the display 564. System 560 includes an irradiator 566 having a light source 565 and a waveguide 567. The waveguide 567 is integrated with the display 564, for example, optically mounted on the back of the display 564. In some implementations, the display 564 may be manufactured on the front side of the substrate and the waveguide 567 on the back side of the substrate.

[0537] Controller 562 may be similar to controller 510 in Figure 1A, and is configured to receive graphic data from computer 561, perform calculations on the graphic data, generate control signals for modulation, transmit them to display 564 via memory buffer 563, and generate and transmit timing signals to activate light source 565. Light emitted from light source 565 is guided in waveguide 567, illuminates the back of display 564, passes through display 564, is diffracted, and forms a holographic light field 568.

[0538] Figure 5F illustrates another system 570, which includes a reflective display 574 with waveguide irradiation. The reflective display 574 may be, for example, a large display. The waveguide 577 of the irradiator 576 is positioned on the front of the reflective display 574. A controller 572, similar to the controller 510 in Figure 5A, can be configured to receive graphic data from a computer 571, perform calculations on the graphic data, generate and transmit control signals for modulation to the display 574 via a memory buffer 573, and generate and transmit timing signals to activate the light source 575 of the irradiator 576. Light coupled from the waveguide 577 of the irradiator 576 is guided to enter the front of the display 574, is diffracted by the display 574, and forms a holographic light field 578.

[0539] Figure 5G illustrates another system 580, which includes a reflective display 584 having a different type of waveguide illumination using a waveguide device 588. A controller 582, similar to the controller 510 in Figure 5A, is configured to generate and transmit control signals corresponding to holographic data (images and / or video) for modulation of the display 584, and to transmit timing signals to operate the irradiator 586. The irradiator 586 can provide light of one or more colors that can be parallel. The waveguide device 588 is positioned in front of the irradiator 586 and the display 584. The waveguide device 588 may include an input coupler 588-1, a waveguide 588-2, and an output coupler 588-3. The input coupler 588-1 is configured to couple collimated light from the irradiator 586 to the waveguide 588-2. The light then travels through the waveguide 588-2 via total internal reflection and enters the output coupler 588-3 at the end of the waveguide 588-2. The output coupler 588-3 is configured to couple the light to the display 584. The light then illuminates the display elements of the display 584, which are modulated with the corresponding control signals, is diffracted by the reflective display 584, and is reflected through the waveguide device 588 (e.g., the output coupler 588-3) (e.g., by the back mirror of the display 584) to form a holographic light field corresponding to the holographic data in front of the viewer.

[0540] In some examples, light is coupled by output coupler 588-3 at an angle perpendicular to the front of waveguide device 588 and / or reflective display 584. In some examples, each of input coupler 588-1 and output coupler 588-2 may include a grating structure, such as a Bragg grating. Input coupler 588-1 and output coupler 588-2 may include similar diffraction gratings with different fringe inclination angles. In some examples, irradiator 586 provides monochromatic light, and input coupler 588-1 and output coupler 588-2 include colored diffraction gratings. In some examples, irradiator 586 provides multiple colored light, such as red, green, and blue light beams, and input coupler 588-1 and output coupler 588-2 may include a multilayer stack (or a single layer with three corresponding diffraction gratings) of three corresponding diffraction gratings that couple different colored light beams into or out, respectively.

[0541] Figure 5H illustrates another system 590, which includes a reflective display 594 having optical diffraction irradiation using an optical diffraction device 598. The optical diffraction device 598 can be considered a light guide device for guiding light. The optical diffraction device 598 may be a transmission field grating-based structure that includes one or more transmission holographic gratings. The reflective display 594 may be a reflective LCOS device. A controller 592, similar to the controller 510 in Figure 5A, may be configured to receive graphic data corresponding to one or more objects from a computer 591, perform calculations on the graphic data, generate control signals for modulation, and transmit them to the display 594 through a memory buffer 593. The controller 592 may also be coupled to an irradiator 596 and configured to provide timing signals to actuate the irradiator 596 to provide light. The light is then diffracted by the optical diffraction device 598 and incident on the display 594, and then diffracted by the display 594 to form a holographic light field 599 corresponding to one or more objects. The display 594 may include a rearview mirror at its rear to reflect light toward the viewer. The optical diffraction device 598 may be optically transparent. The irradiator 596 may be positioned below the display 594, thereby allowing the irradiator 596 to be mounted or housed with other components of the system 590 and to be below the viewer's line of sight.

[0542] As will be discussed in more detail below, Bragg selectivity allows off-axis illuminated light to diffract from the optical diffraction device 598 toward the display 594, while the light diffracted back from the display 594 can approach the axis and therefore be off-Bragd with respect to the grating of the optical diffraction device 598, and thus can pass through the optical diffraction device 598 almost completely without being diffracted again by the grating of the optical diffraction device 598 and reach the viewer. In some implementations, light from the irradiator 596 can be incident on the optical diffraction device 598 from the side of the display 594 at a large angle of incidence, so that the irradiator 596 does not obstruct the viewer's view and does not penetrate the holographic light field 599. The angle of incidence can be a positive or negative angle with respect to the normal of the display 594. For illustrative purposes, the angle of incidence is presented as a positive angle. For example, the angle of incidence can be in the range of 70 to 90 degrees, e.g., 80 to 90 degrees. In a particular example, the angle of incidence is 84 degrees. The diffracted light from the optical diffraction device 598 can be diffracted at near-perpendicular incidence to the display 594 so that the light can uniformly illuminate the display 594 and minimize power loss due to undesirable reflection, diffraction, and / or scattering within or on the surface of the optical diffraction device 598, causing the light to diffract backward almost perpendicular to the viewer's eye through the optical diffraction device 598. In some examples, the diffraction angle from the optical diffraction device 598 to the reflective display 594 can be in the range of -10° (or 10 degrees) to 10° (or 10 degrees), for example, -7° to 7°, or 5° to 7°. In a particular example, the diffraction angle is 6°. In another example, the diffraction angle is 0°.

[0543] In some implementations, as illustrated in Figure 5H, the optical diffraction device 598 is positioned in front of the reflective display 594, for example, along the Z-direction toward the viewer. The optical diffraction device 598 may include a field grid structure 598-1 positioned on a substrate 598-2. The back surface of the field grid structure 598-1 faces the front surface of the reflective display 594, and the front surface of the field grid structure 598-1 is attached to the substrate 598-2. Light from the irradiator 596 can be incident on the front surface of the field grid structure 598-1, for example, from the side surface of the substrate 598-2, through the substrate 598-2. For example, the substrate 598-2 may have wedge-shaped sides, as illustrated in further detail in Figure 12C, so that light with a large incident angle can have less reflection loss.

[0544] As will be discussed in more detail below, if the diffraction efficiency of a diffraction structure, such as a holographic grating, is less than 100%, light incident at a certain angle of incidence can be diffracted by the diffraction structure into zero-order and first-order diffractories. The first-order light (or primary light) is diffracted again by the diffraction structure at the angle diffracted toward the display, reconstructing the holographic light field 599. The first-order may also be called the first order of diffraction. The zero-order light (or zero-order light, or non-diffracted light, or non-diffracted order) is not diffracted (or non-bent) by the diffraction structure and is transmitted by the diffraction structure at an angle corresponding to the angle of incidence. The zero-order light can cause undesirable effects, such as ghost images, for example, when the zero-order light is incident directly or subsequently on the reflective display 594 after being reflected from a surface in the optical diffraction device 598.

[0545] To eliminate undesirable effects, the field grid structure 598-1 can be spaced apart from the display 594. In some implementations, the back surface of the field grid structure 598-1 is spaced apart from the front surface of the display 594 by a gap. The gap can have any preferred distance, for example, 1 mm. The gap can be filled with air or any low refractive index material to satisfy total internal reflection (TIR) ​​at the interface. For example, air has a refractive index (e.g.,) of the back layer of the field grid structure 598-1.

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[0546] In some implementations, instead of being separated by a gap, the back of the field lattice structure 598-1 can be attached to the front of the reflective display 594 using an intermediate layer. The intermediate layer may be an optically transparent adhesive (OCA) layer having a refractive index substantially lower than the refractive index of the rear layer of the field lattice structure 598-1, so that total internal reflection (TIR) ​​can occur, and the remaining zero-order light can be completely reflected back to the optical diffraction structure 598 at the interface between the intermediate layer and the rear layer of the field lattice structure 598-1.

[0547] In some implementations, the field grid structure 598-1 and the display 594 can be separated by a gap so that no afterglow can reach the display 594. The gap can be filled with any suitable transparent material, exponentially matched fluid, or OCA. In some implementations, the field grid structure 598-1 can be formed within the cover layer (e.g., cover glass) of the display 594.

[0548] In some cases, the active area of ​​the field grid structure 598-1 does not need to be smaller than the area of ​​the entire surface of the reflective display 594 in order to illuminate the entire surface of the reflective display 594 with light diffracted from the active area of ​​the field grid structure 598-1. In some implementations, the field grid structure 598-1 and the reflective display 594 have a rectangular shape with height along the X direction and width along the Y direction. The active area of ​​the field grid structure 598-1 can have a height that is not smaller than the height of the reflective display 594 and a width that is not smaller than the width of the reflective display 594. If there is a substantial gap between the field grid structure 598-1 and the reflective display 594, the field grid structure 598-1 and the substrate 598-2 can be further expanded so that the expanded cone (or frustum of cone) of light from the reflective display 594, for example, the holographic light field 599, can be seen through the front of the optical diffraction device 598 over the entire vertical and horizontal field of view of the holographic light field 599 (around the +Z axis). The substrate 598-2 can be made slightly wider and taller than the field grid structure 598-1.

[0549] Since the light is incident on the field lattice structure 598-1 at a substantially off-axis angle in a certain dimension, for example, in the Z direction, the light may be narrower by the cosine of the angle of incidence in that dimension. The light from the irradiator 596 can then have a narrow rectangular shape incident on the field lattice structure 598-1, which can then expand the light into a larger rectangular shape incident on the reflective display 594. One or more optical components, such as mirrors, prisms, optical slabs, and / or optical fillers, can be placed between and within the irradiator 596, the optical diffraction structure 598, and the reflective display 594 to further expand the light and filter its bandwidth. In some examples, the expanded light may have a beam area slightly smaller than the active area of ​​the reflective display 594 so that the edges and surrounding areas of the irradiated region of the reflective display 594 are not noticeable due to reflection or scattering toward the viewer. In some examples, the extended light may have a beam area slightly larger than the active area of ​​the reflective display 594, such that the edges of the extended light are not uniform, for example, due to diffraction from the masking edge, but the edges of the illuminated area of ​​the reflective display 594 are fully illuminated.

[0550] In some implementations, the controller 592 can acquire graphic data containing primitive data for each of several primitives corresponding to an object in three-dimensional space, determine the electromagnetic (EM) field contribution of each of the multiple primitives to each of the multiple display elements of the reflective display 594 for each of the multiple primitives, generate the sum of the EM field contributions from the multiple primitives to each of the multiple display elements for each of the multiple display elements, and generate a control signal for each of the multiple display elements based on the sum of the EM field contributions to the display element.

[0551] In some implementations, the irradiator 596 may include one or more light-emitting elements of the corresponding colors, such as red, blue, or green lasers (or LEDs), configured to emit light of the corresponding colors. The optical diffraction device 598 may be configured to diffract light of several different colors at diffraction angles that are substantially identical to each other. Each of the diffraction angles may be substantially identical to a range of 0° to ±10°, for example, 0°, + or -1°, + or -2°, + or -3°, + or -4°, + or -5°, + or -6°, + or -7°, + or -8°, + or -9°, or + or -10°.

[0552] In some implementations, the controller 592 is configured to sequentially modulate the display 594 with information associated with multiple colors of light over a series of periods. For example, the information may include a series of color holograms or color images. The controller 592 can control the irradiator 596 to sequentially emit each of the multiple colors of light into the optical diffraction device 598 during each period of the series, so that each of the multiple colors of light is diffracted by the optical diffraction device 598 toward the reflective display 594 and diffracted by the modulated display elements of the reflective display 594 to form the respective color three-dimensional holographic light field 599 corresponding to the object during each period. Depending on the temporal coherence of the visual effect on the viewer's eye, the multiple colors can be combined in the eye to give a full-color appearance. In some cases, the illuminator 596 is switched off between different light-emitting elements during changes in the state of the display image (or holographic reconstruction), such as during black insertion subframes between color subframes, during blanking or retracement periods of the video source, or during LC rise, fall, or DC balancing inversion transitions, or during system warm-up, or when the intended holographic light field is completely black, or during calibration procedures, and is switched on once a valid image (or holographic reconstruction) has been presented for a certain period of time. This may also depend on visual persistence to ensure that the image (or holographic reconstruction) appears stable and flicker-free.

[0553] If a portion of the holographic light field 599 appears in front of the display 594, as illustrated by light field 599-1 in Figure 5H, that portion of the holographic light field 599 is the actual portion of the reconstructed image or holographic reconstruction (also called a real image or real holographic reconstruction). When the viewer sees a point of light in front of the display 594, there is actually light that is reflected from the display 594 to that point. If a portion of the light field 599 appears to be behind (or inside) the display 594, as illustrated by light field 599-2 in Figure 5H, that portion of the holographic light field 599 is the virtual portion of the reconstructed image or holographic reconstruction (also called a virtual image or virtual holographic reconstruction). When the viewer sees a point of light that appears to be behind or inside the display 594, there is no actual light diffracted from the display 594 to that virtual point; rather, some of the light diffracted from the display 594 appears to originate at that virtual point.

[0554] Computer 591 and / or controller 592 can be configured to coordinate the calculation (e.g., by equation) of the information modulated in the display 594 (e.g., a two-dimensional hologram, image, or pattern) to move the reconstructed holographic light field 599 back and forth along a direction perpendicular to the display 594 (e.g., the Z direction). The calculation may be based on a holographic rendering process, as illustrated, for example, in Figures 2 and 3A-3G. In some cases, the holographic light field 599 may be entirely in front of the display 594. In some cases, the holographic light field 599 may appear to be entirely behind the display 594. In some cases, as illustrated in Figure 5H, the holographic light field may have a portion in front of the display 594, e.g., a real portion 599-1, and another portion that appears to be behind the display, e.g., a virtual portion 599-2. That is, the light field 599 may appear to span the surface of the display 594, which can be called image planning.

[0555] The optical diffraction device 598 can be implemented in different configurations. In some implementations, the optical diffraction device 598 includes a holographic grating for a specific color, such as a Bragg grating, as illustrated in Figures 7A, 7B, and 8, and the holographic light field 599 can correspond to a specific color. In some implementations, the optical diffraction device 598 includes multiple holographic gratings for different colors in a single recording layer, as illustrated in Figures 7C, 7D, and 7E.

[0556] In some implementations, the optical diffraction device 598 includes multiple holographic gratings for different colors in different recording layers, as illustrated, for example, in Figures 9A-12C. As illustrated in Figure 7F, a grating of a particular color can diffract not only light of that particular color but also light of other colors, which can cause crosstalk between different colors. In some examples, as will be further described below with respect to Figures 9A-10B, the optical diffraction device 598 may include multiple holographic gratings having one or more color-selective polarizers to suppress (e.g., eliminate or minimize) color crosstalk. In some examples, as will be further described below with respect to Figures 11-12C, the optical diffraction device 598 may include multiple holographic gratings having one or more reflective layers for light of different colors incident at each incident angle to suppress color crosstalk and zero-order light. In some examples, the optical diffraction device 598 may include one or more color-selective polarizers, as illustrated in Figures 9A-10B, and multiple holographic gratings having one or more reflective layers, as illustrated in Figures 11-12C, for suppressing color crosstalk and zero-order diffraction. Each of the color-selective polarizers may be configured for a single color or multiple colors. Each of the reflective layers may be configured for a single color or multiple colors.

[0557] Figure 5I illustrates another system 590A, which includes a reflective display 594A having optical diffraction irradiation using an optical diffraction device 598A. The reflective display 594A may be the same as the reflective display 594 in Figure 5H. Unlike the optical diffraction device 598 in system 590 in Figure 5H, the optical diffraction device 598A in system 590A has a reflective field grating-based structure which may include a reflective field grating structure 598-1A and a substrate 598-2A. The substrate 598-2A may be a glass substrate. The reflective field grating structure 598-1A may include one or more reflective holographic gratings for one or more different colors. The reflective field grating structure 598-1A is positioned, for example, on the front surface of the substrate 598-2A along the Z direction. The irradiator 596 is positioned behind the reflective field grating structure 598-1A and is configured to irradiate the reflective field grating structure 598-1A with light at a large angle of incidence. The light is diffracted backward (along the Z direction) by the reflective display 594A, which further diffracts the light backward through the optical diffraction device 598A to form a holographic light field 599.

[0558] Figure 5J illustrates another system 590B, which includes a transmissive display 594B having optical diffraction irradiation using an optical diffraction device 598B. The transmissive display 594B may be the same as the transmissive display 534 in Figure 5C, 544 in Figure 5D, or 564 in Figure 5E. Similar to the optical diffraction structure 598A in Figure 5I, the optical diffraction structure 598B may be a reflection field grating-based structure that includes a reflection field grating structure 598-1B and a substrate 598-2B. The substrate 598-2B may be a glass substrate. The reflection field grating structure 598-1B may include one or more reflection holographic gratings for one or more different colors. Unlike the optical diffraction structure 598A in Figure 5I, the reflection field grating structure 598-1B in the optical diffraction structure 598B is located on the back surface of the substrate 598-2B. The irradiator 596 is positioned in front of the reflection field grating structure 598-1B and is configured to irradiate the reflection field grating structure 598-1B with light at a large angle of incidence. The light is diffracted backward (along the Z direction) relative to the transmissive display 594B, which further diffracts the light to form a holographic light field 599.

[0559] Figure 5K illustrates another system 590C, which includes a transmissive display 594C having optical diffraction irradiation using an optical diffraction device 598C. The transmissive display 594C may be the same as the transmissive display 594C in Figure 5J. Similar to the optical diffraction structure 598 in Figure 5H, the optical diffraction structure 598C may be a transmissive field lattice-based structure that includes a transmissive field lattice structure 598-1C and a substrate 598-2C. The substrate 598-2C may be a glass substrate. The transmissive field lattice structure 598-1C may include one or more transmissive holographic lattices for one or more different colors. Unlike the optical diffraction structure 598 in Figure 5H, the transmissive field lattice structure 598-1C in the optical diffraction structure 598C is located on the front surface of the substrate 598-2C. The irradiator 596 is located behind the transmissive field lattice structure 598-1C and is configured to irradiate the transmissive field lattice structure 598-1C with light at a large angle of incidence. The light is diffracted forward (along the +Z direction) relative to the transmissive display 594C, which further diffracts the light to form a holographic light field 599.

[0560] As discussed above, Figures 5H–5K illustrate different combinations of reflective / transmissive displays and field gratings based on reflective / transmissive optical diffraction devices. In some cases, placing the optical diffraction device behind the display can provide better protection for the photopolymer if the photopolymer is not already protected by its inherent structure or by an additional glass layer. In some cases, the transmissive grating may be mechanically and optically close to the display, and light from the transmissive grating to the display can travel a shorter distance than from the reflective grating, which can reduce alignment, coverage, disper...

Claims

1. An optical device, The first optical diffraction component and The second optical diffraction component, A color-selective polarizer between the first optical diffraction component and the second optical diffraction component, When a first light beam containing light of a first color in a first polarization state is incident on the first optical diffraction component at a first incidence angle, the first optical diffraction component diffracts the light of the first color in the first polarization state at a first diffraction angle with a first diffraction efficiency. When a second light beam containing light of a second color in a second polarization state is incident on the color-selective polarizer, the color-selective polarizer converts the second light beam into a third light beam containing light of the second color in a first polarization state, wherein the second color is different from the first color, and the second polarization state is different from the first polarization state. When the third light beam is incident on the second optical diffraction component at a second incidence angle, the second optical diffraction component diffracts the light of the second color in the first polarization state at a second diffraction angle with a second diffraction efficiency. The diffraction efficiency of the first optical diffraction component that diffracts light of the second color in the second polarization state is smaller than the diffraction efficiency of the first optical diffraction component that diffracts light of the first color in the first polarization state. An optical device in which the first optical diffraction component and the second optical diffraction component include corresponding transmission gratings for light of the first color and light of the second color.

2. An optical device, The first optical diffraction component and The second optical diffraction component, A color-selective polarizer between the first optical diffraction component and the second optical diffraction component, Light of the first color, at a first angle of incidence and in a first polarization state, produces the first optical diffraction pattern When incident on the element, the first optical diffraction component diffracts the light of the first color at a first diffraction angle with a first diffraction efficiency. When light of a second color, different from the light of the first color, is incident on the first optical diffraction component at a second incident angle in a second polarization state different from the first polarization state, the first optical diffraction component diffracts the light of the second color with a diffraction efficiency lower than the first diffraction efficiency. When light of the second color in the second polarization state is incident on the color-selective polarizer, the color-selective polarizer rotates the polarization state of the light of the second color from the second polarization state to the first polarization state. When light of the second color is incident on the second optical diffraction component at the second incidence angle and in the first polarization state, the second optical diffraction component diffracts the light of the second color at the second diffraction angle with the second diffraction efficiency. An optical device in which the first optical diffraction component and the second optical diffraction component include corresponding transmission gratings for light of the first color and light of the second color.

3. An optical device, i) A first optical diffraction component configured to diffract light of a first color in a first polarization state incident at a first angle of incidence with a first diffraction angle and a first diffraction efficiency, and ii) a first optical diffraction component configured to diffract light of a second color in a second polarization state incident at a second angle of incidence with a diffraction efficiency lower than the first diffraction efficiency, A color-selective polarizer, configured to rotate the polarization state of light of a second color in a second polarization state incident on the color-selective polarizer from the second polarization state to the first polarization state, The system comprises a second optical diffraction component configured to diffract light of the second color in the first polarization state, incident at the second incidence angle, at a second diffraction angle and with a second diffraction efficiency, The color-selective polarizer is located between the first optical diffraction component and the second optical diffraction component. An optical device in which the first optical diffraction component and the second optical diffraction component include corresponding transmission gratings for light of the first color and light of the second color.

4. The optical device according to any one of claims 1 to 3, wherein the second optical diffraction component is configured to diffract light of the first color in the second polarization state at the first incident angle with a diffraction efficiency lower than the second diffraction efficiency.

5. The optical device according to claim 4, wherein the first optical diffraction component, the color-selective polarizer, and the second optical diffraction component are sequentially stacked such that light of the first color and light of the second color are incident on the first optical diffraction component before the second optical diffraction component.

6. A third optical diffraction component, The present invention further comprises a second color-selective polarizer between the second optical diffraction element and the third optical diffraction element, The optical device according to claim 4 or 5, wherein the second color-selective polarizer is configured to rotate the polarization state of the light of the third color from a second polarization state to a first polarization state when light of the third color is incident on the second color-selective polarizer in a second polarization state, and the third optical diffraction component is configured to diffract the light of the third color at a third diffraction efficiency and at a third diffraction angle when light of the third color is incident on the third optical diffraction component at a third incidence angle and in a first polarization state.

7. The color-selective polarizer is configured to rotate the polarization state of the light of the first color from the first polarization state to the second polarization state, and the second color-selective polarizer is configured to rotate the polarization state of the light of the second color from the first polarization state to the second polarization state without rotating the polarization state of the light of the first color, and / or A third color-selective polarizer configured to rotate the polarization states of the first and second colored lights from a second polarization state to a first polarization state without rotating the polarization state of the third colored light, wherein the third optical diffraction component further comprises a third color-selective polarizer located between the second color-selective polarizer and the third color-selective polarizer, and / or The third optical diffraction component is configured to diffract each of the light of the first color and the light of the second color incident in the second polarization state with a diffraction efficiency lower than the third diffraction efficiency, the first optical diffraction component is configured to diffract the light of the third color incident in the second diffraction efficiency with a diffraction efficiency lower than the first diffraction efficiency, the second optical diffraction component is configured to diffract each of the light of the first color and the light of the third color incident in the second polarization state with a diffraction efficiency lower than the second diffraction efficiency, and / or The second color-selective polarizer comprises a pair of first and second subpolarizers, wherein the first subpolarizer is configured to rotate the polarization state of the second color light from a first polarization state to a second polarization state without rotating the polarization states of the first and third color light respectively, and the second subpolarizer is configured to rotate the polarization state of the third color light from a second polarization state to a first polarization state without rotating the polarization states of the first and second color light respectively, and / or The optical device according to claim 6, wherein the optical device is a fourth color-selective polarizer configured to rotate the polarization state of the first color of light from a second polarization state to a first polarization state without rotating the polarization states of the second color of light and the third color of light, and the first optical diffraction component further comprises a fourth color-selective polarizer located between the fourth color-selective polarizer and the color-selective polarizer.

8. The optical device according to claim 6 or 7, wherein each of the first optical diffraction component, the second optical diffraction component, and the third optical diffraction component comprises a holographic grating formed on a recording medium.

9. The recording medium comprises a photosensitive polymer and / or The recording medium is optically transparent and / or Each of the holographic grids is fixed to the recording medium and / or Each of the first optical diffraction component, the second optical diffraction component, and the third optical diffraction component comprises a carrier film attached to the recording medium and / or Each of the first optical diffraction component, the second optical diffraction component, and the third optical diffraction component comprises a diffraction substrate attached to the other side of the recording medium opposite to the carrier film, and / or The optical device according to claim 8, wherein the carrier film of the first optical diffraction component is attached to the first side of the color-selective polarizer, the diffraction substrate of the second optical diffraction component is attached to the second opposite side of the color-selective polarizer, the carrier film of the second optical diffraction component is attached to the first side of the second color-selective polarizer, and the diffraction substrate of the second optical diffraction component is attached to the second opposite side of the second color-selective polarizer.

10. The circuit board is further equipped, The optical device according to any one of claims 1 to 9, wherein the first optical diffraction component is located between the substrate and the color-selective polarizer.

11. The optical device further comprises an anti-reflective coating on the surface of the substrate and / or The optical device further comprises a front and a back, and / or The light of the first color and the light of the second color are incident on the front surface, and the optical device further comprises an anti-reflective coating on the back surface and / or The optical device comprises a plurality of optical components, including the first optical diffraction component, the color-selective polarizer, and the second optical diffraction component, and / or The optical device according to claim 10, wherein two adjacent optical components among the plurality of components are mounted together through a refractive index matching material.

12. Each of the first optical diffraction component and the second optical diffraction component comprises a Bragg grating formed in the recording medium, The optical device according to any one of claims 1 to 3, wherein each Bragg grid comprises a plurality of fringe planes, each having a fringe inclination angle θt and a fringe spacing Λ perpendicular to the fringe planes within the volume of the recording medium.

13. Each Bragg grating, when the angle of incidence to the recording medium is the on-Bragg angle, satisfies Bragg's equation mλ = 2 n Λ sin(θm - θt) It is configured such that, in the formula, λ represents the respective wavelengths of light of a certain color in a vacuum, n represents the refractive index in the recording medium, θm represents the m-th order Bragg angle of diffraction in the recording medium, θt represents the fringe slope in the recording medium, and / or The first angle of incidence and the second angle of incidence are each the same as the On-Bragg angle, and the first diffraction angle and the second diffraction angle are each the same as the primary Bragg angle, and / or The fringe inclination angle of each of the Bragg grids is the same as 45 degrees, and / or The thickness of the recording medium is more than an order of magnitude greater than the fringe spacing, and / or The thickness of the recording medium is 30 times greater than the fringe spacing, and / or The first diffraction angle and the second diffraction angle are the same as each other, and / or The first diffraction angle and the second diffraction angle are each in the range of -10 degrees to 10 degrees, and / or The first diffraction angle and the second diffraction angle are both the same as 0 degrees, and / or The first diffraction angle and the second diffraction angle are each in the range of -7 degrees to 7 degrees, and / or The first diffraction angle and the second diffraction angle are both the same as 6 degrees, and / or The first diffraction angle and the second diffraction angle are each in the range of 70 degrees to 90 degrees, and / or The optical device according to claim 12, wherein the first diffraction angle and the second diffraction angle are the same as each other.

14. The first polarization state is s-polarization, and the second polarization state is p-polarization. The first optical diffraction component is configured to diffract the second color light incident in the second polarization state with a diffraction efficiency at least one order of magnitude smaller than the first diffraction efficiency, and the color-selective polarizer is configured not to rotate the polarization state of the first color light. The optical device according to any one of claims 1 to 3, wherein the optical device is a second color-selective polarizer configured to rotate the polarization state of the light of the first color from a second polarization state to a first polarization state without rotating the polarization state of the light of the second color, and the first optical diffraction component further comprises a second color-selective polarizer located between the second color-selective polarizer and the color-selective polarizer.

15. The first optical diffraction component comprises a first diffraction structure, and the second optical diffraction component comprises a second diffraction structure. The optical device comprises a first reflective layer and a second reflective layer, wherein the first reflective layer is located between the first diffraction structure and the second diffraction structure, and the second diffraction structure is located between the first reflective layer and the second reflective layer. The first diffraction structure is configured to: i) diffract primary and zero-order light of the first color incident at a first incidence angle, wherein the primary light is diffracted at the first diffraction angle and the zero-order light is transmitted at the first incidence angle; and ii) transmit second color light incident at a second incidence angle to the first diffraction structure. The first reflective layer is configured to: i) completely reflect light of the first color incident on the first reflective layer at the first angle of incidence, and ii) transmit light of the second color incident on the first reflective layer at the second angle of incidence. The optical device according to any one of claims 1 to 3, wherein the second diffraction structure is configured to diffract primary and zero-order light of the second color incident at a second incidence angle, the primary light is diffracted at a second diffraction angle, the zero-order light is transmitted at a second incidence angle, and the second reflective layer is configured to completely reflect the light of the second color incident at a second incidence angle.

16. It is a system, An irradiator configured to provide light of multiple different colors, The optical device includes the one described in any one of claims 1 to 15, A system in which the optical device is positioned adjacent to the irradiator and is configured to receive the plurality of different colored lights from the irradiator and to diffract the plurality of different colored lights.

17. The system according to claim 16, wherein the optical device is configured to diffract the plurality of different colored lights at their respective diffraction angles, each of which is in the range of -10 degrees to 10 degrees.

18. The system according to claim 16 or 17, further comprising a controller coupled to the irradiator and configured to control the irradiator to provide each of the plurality of different colored lights.

19. The system further includes a display comprising a plurality of display elements, wherein the optical device is configured to diffract the plurality of colors of light toward the display and / or The controller is coupled to the display and is configured to transmit respective control signals to each of the plurality of display elements for modulation of at least one characteristic of the display elements, and / or The controller acquires graphic data including primitive data for each of the multiple primitives corresponding to an object in three-dimensional space, determines the electromagnetic (EM) field contribution of the display to each of the multiple display elements for each of the multiple primitives, and for each of the multiple display elements The system according to claim 18, configured to generate the sum of the EM field contributions to the display element from the plurality of primitives, and for each of the plurality of display elements, generate the respective control signals based on the sum of the EM field contributions to the display element.

20. It is a system, A display with multiple display elements, The optical device includes the one described in any one of claims 1 to 15, A system in which the optical device is configured to diffract light of multiple different colors toward the display.

21. The system according to claim 20, wherein the optical device and the display are arranged along a certain direction, the optical device has a front and a back along the direction, the display has a front and a back along the direction, and the front of the display is spaced apart from the back of the optical device.

22. The front surface of the display is separated from the back surface of the optical device by a gap, and / or At least one of the front surface of the display or the back surface of the optical device is treated with an anti-reflective coating and / or The system further includes a transparent protective layer on the back surface of the optical device and / or The front of the display and the back of the optical device are attached together by an intermediate layer, and / or The intermediate layer is configured to have a refractive index lower than that of the layer of the optical device, such that each of the plurality of colors of light transmitted in zero order by the optical device is completely reflected at the interface between the intermediate layer and the layer of the optical device, and / or The system further includes a cover on the front surface of the display, the optical device is formed within the cover glass, and / or The optical device is configured to receive the plurality of colors of light on the front surface of the optical device, and / or The optical device is configured to diffract the plurality of different colored lights at their respective diffraction angles, and / or Each of the aforementioned diffraction angles is in the range of -10 degrees to 10 degrees, and / or The display is configured to diffract the diffracted color light backward through the optical device, and / or A region of the optical device covers a region of the display and / or The display comprises a spatial light modulator (SLM) including a digital micromirror device (DMD) or a liquid crystal on silicon (LCOS) device, and / or The system according to claim 21, further comprising an optical polarizer disposed between the display and the optical device, wherein the optical polarizer is configured to change the polarization state of the plurality of different colored lights.

23. The system according to claim 21 or 22, wherein the optical device comprises a substrate in front of the optical device and is configured to receive the plurality of colored lights from at least one side of the substrate.

24. The optical device is configured to have a substrate in front of it and to receive the plurality of colors of light from at least one side of the substrate, and / or The optical device comprises at least one diffraction grating supported by the substrate and configured to diffract the plurality of different colored lights toward the display, and / or The substrate comprises a container filled with a liquid having a refractive index smaller than that of the recording medium of the diffraction grating, and / or The substrate is wedge-shaped and has an inclined front surface, and / or The angle between the front surface and the side surface is less than 90 degrees, and / or The optical device is configured to receive different portions of the plurality of different colored lights along different optical paths within the substrate, and to diffract the different portions to illuminate different corresponding areas of the display, and / or The aforementioned different regions comprise two or more of the lower region, upper region, left region, and right region of the display, and / or The aforementioned different portions of light of multiple different colors are provided by different corresponding irradiators and / or, The optical device is configured to receive different portions of the plurality of different colored lights from different corresponding sides of the substrate, and / or The optical device is configured to receive a first portion of the plurality of different colored lights from a first side surface of the substrate to the back surface of the optical device, diffract the first portion to illuminate a first area of ​​the display, and / or to receive a second portion of the plurality of different colored lights from a second side surface of the substrate to the front surface of the optical device, reflect the second portion backward against the back surface of the optical device, diffract the second portion to illuminate a second area of ​​the display, and / or The first side and the second side are the same side, and / or The second portion of the plurality of different colored lights is reflected by total internal reflection or a reflection grating within the optical device, and / or The system according to claim 23, wherein the substrate comprises a partially reflective surface configured to separate the input light into a first portion and a second portion.

25. The system according to claim 21 or 22, wherein the optical device comprises at least one diffraction grating disposed on the back surface of the optical device.

26. The diffraction grating comprises different subregions having different corresponding diffraction efficiencies, and / or The diffraction grating is configured to diffract a first portion of the plurality of different colored light incident on a first sub-region of the diffraction grating to illuminate a first region of the display, and further to reflect a second portion of the plurality of different colored light, which is reflected backward from the back surface of the optical device and incident on a second sub-region of the diffraction grating, back to the front surface of the optical device, and to diffract the second portion to illuminate a second different region of the display, and / or The diffraction grating is configured such that the diffracted first portion and the diffracted second portion on the first and second regions of the display have the same optical power, and / or The system according to claim 25, wherein the first region and the second region of the display have different reflectances associated with a first different diffraction efficiency and a second different diffraction efficiency of the first sub-region and the second sub-region of the diffraction grating.

27. The system according to claim 25 or 26, wherein the diffraction grating comprises a plurality of sub-regions tiled together.

28. The diffraction grating comprises a plurality of sub-regions tiled together, and / or The aforementioned sub-region is tiled along the horizontal direction and / or The edges of the different sub-regions are configured to contact each other in an optically seamless manner, and / or The distinct sub-regions are formed by including one or more edge-defining elements in at least one optical path of the recording beam or object beam when recording each sub-region on the recording medium, and the one or more edge-defining elements comprises a square aperture, a rectangular aperture, or a planar tile aperture, and / or Two adjacent sub-regions of the diffraction grating are in contact with the gap, and / or The display comprises a plurality of tile-like display devices, and the gap between adjacent sub-regions of the diffraction grating is aligned with the gap between adjacent tile-like display devices of the display, and / or Two adjacent and distinct subregions have an overlap, and / or The diffraction grating is mechanically formed by using an embossed structure, a nanoimprinted structure, or a self-assembled structure, and / or The system according to claim 27, wherein the display has a width along the horizontal direction and a height along the vertical direction, both the horizontal and vertical directions being perpendicular to the direction, and the aspect ratio of the width to the height is greater than 16:

9.

29. The system according to any one of claims 24 to 28, further comprising an irradiator positioned adjacent to the optical device and configured to provide the optical device with light of the plurality of colors.

30. The irradiator comprises a plurality of light-emitting elements, each configured to emit light of a different color, and / or The centers of the beams from the plurality of light-emitting elements are offset from each other, and / or The irradiator is configured to provide a light beam having an elliptical beam profile or a rectangular beam profile, and / or The irradiator is configured to provide a light beam with a specific polarization orientation, and / or The irradiator comprises one or more optical components configured to independently control the ellipticity and polarization orientation of each of the plurality of different colored lights, and / or The irradiator comprises one or more optical components configured to control the uniformity of the plurality of different colored lights, and / or The one or more optical components include an apodizing optical element or a profile converter, and / or The system according to claim 29, wherein the system includes one or more anamorphic optical elements or one or more cylindrical optical elements configured to increase the width of the plurality of different colored lights.

31. A prism element between the irradiator and the optical device, configured to receive the plurality of different colored lights from the input surface of the prism element, The system according to claim 29 or 30, comprising one or more expansion gratings adjacent to the exit surface of the prism element, each of which is configured to expand the beam profiles of light of different corresponding colors by a coefficient of at least one dimension.

32. The system further comprises one or more reflectors located downstream of the one or more expansion diffraction gratings, each of the one or more reflectors reflecting light of its respective color to the optical device. It is configured to fire, and / or, The tilt angle of each of the one or more reflectors is independently adjustable to cause uniformity of diffraction from the optical device to the display, and / or The system further includes at least one of a color sensor or a luminance sensor configured to detect one or more optical properties of the holographic light field formed by the system, wherein the tilt angle of the one or more reflectors is adjustable based on the detected optical properties of the holographic light field, and / or The one or more optical properties include brightness uniformity, color uniformity, or a white point, and / or The one or more reflectors are adjustable to compensate for changes in the alignment of the components of the system, and / or The optical distance between the one or more reflectors and the optical device is configured such that each of the multiple different colored lights is reflected by the corresponding reflector without transmission through one or more other reflectors, and / or The one or more reflectors are configured such that the light emitted from each of the one or more reflectors comes from different directions, and / or The angle between the prism element and the substrate of the optical device is adjustable so as to tilt the position of the holographic light field formed by the system, and / or The system according to claim 31, wherein one or more extended gratings are configured to collimate the plurality of different colored lights in one or two transverse directions, at least partially.

33. The system according to any one of claims 29 to 32, further comprising a controller coupled to the irradiator and configured to control the irradiator to provide each of the plurality of colors of light.

34. The controller is coupled to the display and is configured to transmit respective control signals to each of the plurality of display elements for modulation of at least one characteristic of the display elements, and / or The controller is configured to acquire graphic data including primitive data for each of a plurality of primitives corresponding to an object in three-dimensional space, determine the electromagnetic (EM) field contribution of each of the plurality of primitives to each of the plurality of display elements of the display, generate the sum of the EM field contributions from the plurality of primitives to each of the plurality of display elements, and / or generate the respective control signals for each of the plurality of display elements based on the sum of the EM field contributions to the display element, and / or The controller is configured to sequentially modulate the display with information associated with the plurality of colors of light over a series of periods, and to control the irradiator to sequentially emit each of the plurality of colors of light to the optical device during each period of the series of periods, such that each of the plurality of colors of light is diffracted toward the display by the optical device and reflected by the modulated display elements of the display to form a three-dimensional light field of each color corresponding to the object within each period, and / or The system according to claim 33, wherein the controller is configured to modulate the display such that each of the three-dimensional color light fields appears i) entirely in front of the display, ii) entirely behind the display, or iii) partially in front of the display and partially behind the display.

35. The optical device illuminates the display element with light containing the plurality of different colors. The system according to any one of claims 20 to 34, further comprising an optical diffraction component configured to diffract a portion of the light emitting to the display, which is configured to diffract a portion of the light.

36. The optical device further comprises an optical redirection component configured to transmit a portion of the light to form a holographic scene and to redirect the zeroth-order display light away from the holographic scene in three-dimensional (3D) space, wherein the zeroth-order display light includes reflected light from the display and / or The optical redirection component comprises a plurality of redirection holographic gratings for the display zero-order light of the plurality of different colored lights, and each of the plurality of redirection holographic gratings is configured to diffract the display zero-order light of each of the plurality of different colored lights in the 3D space in the respective direction and at the respective diffraction angle, and / or The optical diffraction component is configured to diffract the plurality of different colored lights so as to redirect the zero-order light of the display reflected from the display away from the holographic scene, thereby illuminating the display at a 0° angle, and / or The ratio of the amount of the zero-order display light in the holographic scene with the suppression of the optical diffraction component and the optical redirection component to the amount of the zero-order display light in the holographic scene without the suppression is less than 2%, and / or The system according to claim 35, wherein the optical redirection component comprises a one-dimensional suppression grating, the holographic scene includes a band corresponding to the suppression of zero-order light of the display, and the system is configured such that the band lies outside the viewer's field of view.

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