Direct projection multiplexed light field display

Abstract

Multiplexed light field projectors and multiplexed light field displays that output light field images are described.SOLUTION: The projector has a projector base with projection optics configured to output light rays to form a projected image, as well as collimating optics configured to collimate the light rays of the projected image to form a second projected image, wherein the second projected image is directed to the display optics to produce a light field image. The light field projector, or an alternative projector, can be used individually or in combination with one or more other projectors that can be arranged to form a multiplexed direct projection light field display. The projectors can be arranged to have separate display optics or to have shared display optics.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This disclosure relates to light field display technology, and more particularly to projection-based light field displays and light field projectors, particularly single multiplexed light field projectors that can be multiplexed independently or in an array of devices to form high angular resolution, wide field of view, multi-view displays. [Background technology]

[0002] Light field displays offer multiple views, allowing a user to receive a separate view for each eye. Current displays in this field offer interesting viewing experiences, but compelling light field displays require high pixel density, low angular separation between views, and a wide viewing angle. For a high-quality viewing experience, it is desirable for the user to experience smooth transitions between view zones while maintaining perceptible views independent of adjacent views. Three-dimensional displays allow viewers to gain a wider perspective of the image they are viewing. Some three-dimensional displays use polarization, requiring viewers to wear specialized glasses. Other three-dimensional displays produce images that provide some degree of parallax in one dimension.

[0003] Projection-based light field displays typically consist of one or more projectors and typically require a series of optical systems to generate the light field. To achieve the number of pixels required to achieve a high-resolution light field display, an increasing number of projectors combined with multiple optical systems is required, resulting in a large and often costly system.

[0004] U.S. Patent Application Publication No. 2018 / 0101018 to Chung et al. describes a light field display including a screen, a lattice pixel array, and an image generator. This system requires a lattice pixel array to display the output light field image, resulting in a large display with significant power requirements.

[0005] U.S. Patent No. 9,383,591 to Pasolini describes a picoprojector having a light source for generating a light beam, a mirror mechanism for directing the light beam toward a display surface, and a drive circuit for providing drive signals for the mirror mechanism to generate and remove compensation signals for stabilizing the projected image. The described picoprojector uses a gyroscope to compensate for device motion. While this device can generate a projected image, additional optics and processing are required to generate the light field.

[0006] This background information is provided for the purpose of making known information believed by the applicant to be of possible relevance to the present invention. It is not necessarily intended, nor should it be construed, that any of the preceding information constitutes prior art against the present invention. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] U.S. Patent Application Publication No. 2018 / 0101018 [Patent Document 2] U.S. Patent No. 9,383,591 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention aims to provide a multiplexed light field projector and a multiplexed light field display. A multiplexed light field projector, or any other suitable projector, includes a multiplexing device that can be arranged in an array to form a multiplexed direct-projection light field display. A multiplexed light field projector comprises one or more light-emitting diodes, a projector body, and an optical system that combines the multiple light beams generated by the light-emitting diodes into a multiplexed light field. It is a further object of the present invention to provide a multiplexing method for constructing a high-definition light field display. The light field display can be a projection-based light field display or a flat-panel display. Both types include a multiplexing device. [Means for solving the problem]

[0009] In one aspect, a projector is provided that includes a light source including a light emitting diode (LED); a projection optical system including at least one illumination optical component that receives light from the light source and directs it into a single light ray path, a pixel forming device that receives light from the illumination optical component and converts it into a pixel array, and a magnification optical component that receives the pixel array; a collimating optical component that collimates light from the pixel array and generates a collimated projected image; a display optical system including display optical components; and a multiplexing device connected to at least one of the illumination optical component, the pixel forming device, the magnification optical component, and the display optical component and that shifts the light ray path to provide a multiplexed light field output.

[0010] In one embodiment, the illumination optics include at least one of a plano-convex lens, a dichroic mirror, a microlens array, a meniscus lens, a bi-convex lens, a single prism, and a folding prism.

[0011] In another embodiment, the pixel forming device is a Liquid Crystal On Silicon (LCOS) panel or a Digital Micromirror Device (DMD).

[0012] In another embodiment, the magnifying optic is a projection doublet, or a biconvex lens.

[0013] In another embodiment, the collimating optics includes at least one of a Light Field Projection (LFP) lens, a bi-convex lens, and a collimating lens array including a plurality of collimating lenslets.

[0014] In another embodiment, each collimating lenslet in the plurality of collimating lenslets includes two plano-convex lenses.

[0015] In another embodiment, the display optics include at least one of a single lens, a lens array, a pinhole array, a metasurface, and a metalens.

[0016] In another embodiment, the multiplexing device comprises a voltage generator connected to a first electrode and a second electrode, the first electrode and the second electrode being attached to the multiplexing device of illumination optics, pixel forming devices, magnifying optics, or display optics capable of producing the Kerr effect.

[0017] In another embodiment, the multiplexing device is a multiplexing layer located in front of the display optics.

[0018] In another embodiment, the multiplexing device is a multiplexing actuator.

[0019] In another embodiment, the multiplexed actuator is a piezoelectric actuator, an electrothermal actuator, a magnetic actuator, an electrostatic actuator, or a shape memory alloy based actuator.

[0020] In another embodiment, the multiplexed light field output includes a first image at a first location and a second image at a second location, the second image being offset relative to the first image by a distance less than one pixel width.

[0021] In another aspect, a method for generating a multiplexed light field image is provided, comprising generating light rays from a light source along a light ray path, directing the light rays to a pixel forming device, converting the light rays to a pixel array, expanding the pixel array to form an expanded pixel array, collimating the expanded pixel array to generate a collimated projected image, directing the collimated projected image to display optics to generate a light field output, and shifting the light ray path to multiplex the light field output to generate a multiplexed light field image.

[0022] In one embodiment, the light beam is directed to the pixel forming device by one or more plano-convex lenses, dichroic mirrors, microlens arrays, meniscus lenses, bi-convex lenses, simple prisms, and folding prisms.

[0023] In another embodiment, the light rays are converted into pixels by a liquid crystal on silicon (LCOS) panel or a digital micromirror device (DMD).

[0024] In another embodiment, the pixel array is optically magnified by a projection doublet or biconvex lens.

[0025] In another embodiment, the enlarged pixel array is collimated by a light field projection (LFP) lens, a biconvex lens, or a collimating lens array comprising multiple collimating lenslets.

[0026] In another embodiment, the method further includes shifting the light ray path by applying a voltage to the first electrode and the second electrode, wherein the first electrode and the second electrode are attached to illumination optics, pixel formation device, magnification optics, or display optics multiplexing device capable of producing the Kerr effect.

[0027] In another embodiment, the method further comprises shifting the ray path using a multiplexing layer.

[0028] In another embodiment, the method further includes shifting the light path by moving the position of an optical component within the projector using one or more piezoelectric actuators, electrothermal actuators, magnetic actuators, electrostatic actuators, and shape memory alloy based actuators.

[0029] In another embodiment, the multiplexed light field output includes a first image at a first location and a second image at a second location, the second image being offset relative to the first image by a distance less than one pixel width.

[0030] In another aspect, a method for generating a multiplexed light field image is provided, comprising the steps of generating light rays from a light source along a ray path, converting the light rays to a pixel array, magnifying the pixel array, collimating the magnified pixel array to generate a collimated projection image, displaying the collimated projection image to generate a light field output, and shifting the ray path to multiplex the light field output to generate a multiplexed light field image.

[0031] In one embodiment of the method, shifting the light path includes moving the position of a shiftable optical element within the projector, applying a voltage to a multiplexer of optical components capable of producing the Kerr effect, deforming a deformable optical element, or placing a multiplexer layer in the light path.

[0032] In another aspect, a multiplexed light field projector is provided that includes, along an optical path, an LED light source, and a projection optical system having a microlens array, a lens, a prism and a pixel forming device, a collimating optical system including a lens, a display optical system, and a multiplexing device that shifts the optical path.

[0033] In one embodiment, the LED light source comprises red, green, and blue light sources, and the projection optics further comprises a plurality of dichroic mirrors that direct light from the LED light sources.

[0034] In another embodiment, the multiplexing device is connected to at least one of a microlens array, a lens, a prism, a pixel forming device, a lens of a collimating optics, or an optical component of a display optics. [Brief explanation of the drawings]

[0035] These and other features of the present invention will become more apparent in the following detailed description taken in conjunction with the accompanying drawings.

[0036] [Figure 1] FIG. 1 illustrates an isometric view of a light field projector according to one embodiment of the present disclosure.

[0037] [Figure 2A] FIG. 1 shows the configuration of a multiplexed light field projector with projection optics arrangement and collimating optics.

[0038] [Figure 2B] FIG. 1 shows the configuration of a multiplexed light field projector with projection optics arrangement and collimating optics.

[0039] [Figure 2C] FIG. 1 shows the configuration of a multiplexed light field projector with projection optics arrangement and collimating optics.

[0040] [Figure 2D] FIG. 1 shows the configuration of a multiplexed light field projector with projection optics arrangement and collimating optics.

[0041] [Figure 2E] FIG. 1 shows the configuration of a multiplexed light field projector with projection optics arrangement and collimating optics.

[0042] [Figure 2F] FIG. 1 shows the configuration of a multiplexed light field projector with projection optics arrangement and collimating optics.

[0043] [Figure 2G] FIG. 1 shows the configuration of a multiplexed light field projector with projection optics arrangement and collimating optics.

[0044] [Figure 2H] FIG. 1 shows the configuration of a multiplexed light field projector with projection optics arrangement and collimating optics.

[0045] [Figure 2I] FIG. 1 shows the configuration of a multiplexed light field projector with projection optics arrangement and collimating optics.

[0046] [Figure 3A] FIG. 10 shows another configuration of a multiplexed light field projector with projection optics arrangement and collimating optics.

[0047] [Figure 3B] FIG. 10 shows another configuration of a multiplexed light field projector with projection optics arrangement and collimating optics.

[0048] [Figure 3C]FIG. 10 shows another configuration of a multiplexed light field projector with projection optics arrangement and collimating optics.

[0049] [Figure 3D] FIG. 10 shows another configuration of a multiplexed light field projector with projection optics arrangement and collimating optics.

[0050] [Figure 4A] 10A and 10B are diagrams showing another configuration of the arrangement of the projection optical system and the collimating optical system;

[0051] [Figure 4B] 10A and 10B are diagrams showing another configuration of the arrangement of the projection optical system and the collimating optical system;

[0052] [Figure 4C] 10A and 10B are diagrams showing another configuration of the arrangement of the projection optical system and the collimating optical system;

[0053] [Figure 4D] 10A and 10B are diagrams showing another configuration of the arrangement of the projection optical system and the collimating optical system;

[0054] [Figure 5A] 10A and 10B are diagrams showing another configuration of the arrangement of the projection optical system and the collimating optical system;

[0055] [Figure 5B] 10A and 10B are diagrams showing another configuration of the arrangement of the projection optical system and the collimating optical system;

[0056] [Figure 5C] 10A and 10B are diagrams showing another configuration of the arrangement of the projection optical system and the collimating optical system;

[0057] [Figure 6A] FIG. 2 is a front view of a collimating lens array.

[0058] [Figure 6B] FIG. 6B is a close-up view of a 2×4 grid of the collimating lens array of FIG. 6A.

[0059] [Figure 6C] FIG. 6B is a profile view of the collimating lens array of FIG. 6A.

[0060] [Figure 6D] FIG. 6B is an isometric view of a single lens in the collimating lens array of FIG. 6A.

[0061] [Figure 7A] FIG. 1 is a diagram of an engineered diffuser.

[0062] [Figure 7B] FIG. 10 is a close-up view of the laser-etched engineered diffuser.

[0063] [Figure 7C] FIG. 2 is an enlarged view of the diffuser lens array.

[0064] [Figure 8A] FIG. 2 is a diagram of a display lens of the display optical system.

[0065] [Figure 8B] FIG. 10 is a diagram of another display optical system comprising a metasurface.

[0066] [Figure 8C] FIG. 10 is a diagram of another display optical system.

[0067] [Figure 9] FIG. 1 is a sample diagram showing ray paths for a single pixel of one embodiment of a light field projector.

[0068] [Figure 10] FIG. 10 is a sample diagram showing ray paths for a single pixel of another embodiment of a light field projector.

[0069] [Figure 11] FIG. 1 is a sample diagram showing ray paths for a single pixel and optical components of one embodiment of a light field projector.

[0070] [Figure 12] FIG. 10 is a sample diagram showing ray paths for a single pixel and optical components of another embodiment of a light field projector.

[0071] [Figure 13] FIG. 10 is a sample diagram showing ray paths for a single pixel and optical components of another embodiment of a light field projector.

[0072] [Figure 14] FIG. 1 is a diagram of the point spread function of a pixel in an optical diffuser array.

[0073] [Figure 15] FIG. 1 is an isometric view of a system consisting of an array of light projectors.

[0074] [Figure 16] FIG. 1 is an exploded view of a system consisting of an array of light projectors.

[0075] [Figure 17] FIG. 10 shows another configuration of a light field projector including a 3x4 display unit and an array of light field projectors.

[0076] [Figure 18] Figure 1 shows another configuration of a light field projector, including an array of display units and all optics to create a light field display. This system can be tiled / stacked to create a larger display.

[0077] [Figure 19] FIG. 1 is a block diagram of an optical projector.

[0078] [Figure 20A] FIG. 2 is a diagram showing a projector and a projected image together with an optical path.

[0079] [Figure 20B] FIG. 1 illustrates pixel allocation within a projector frame for an active image, overlap region, and correction buffer.

[0080] [Figure 21] FIG. 1 is an exploded isometric view of a light field display.

[0081] [Figure 22] FIG. 1 is an exploded isometric view of an exemplary embodiment of a light field display.

[0082] [Figure 23] FIG. 1 illustrates a top view of a light field display and a multiplexing method according to the present disclosure.

[0083] [Figure 24] FIG. 10 is a top view of another embodiment of a light field display illustrating the multiplexing method.

[0084] [Figure 25] FIG. 1 illustrates a top view of one embodiment of a multiplexed flat panel light field display.

[0085] [Figure 26] FIG. 10 illustrates a top view of another embodiment of a multiplexed flat panel light field display. DETAILED DESCRIPTION OF THE INVENTION

[0086] This document describes a multiplexed, multi-view, autostereoscopic, high angular resolution light field display that can be viewed with both horizontal and vertical parallax. Multiplexing a light field display is a method of increasing the density of views (pixels) by shifting the ray paths or light field within or from a projector.

[0087] Multiplexing is generally a method of simultaneously transmitting multiple signals over a link. Specifically, in the case of light field displays, multiplexing refers to transmitting multiple images for each multiplexed frame in the time frame in which a single frame is transmitted in a non-multiplexed display, corresponding to some variation in the display's optics. A multiplexed image includes two or more light field images, each projected at a different location. This contrasts with a non-multiplexed image or a non-multiplexed output, which outputs or includes only a single projected light field image. By using multiplexing at a high frame rate to generate multiple images from the same projector, the light field image or pixel density is effectively multiplied by the number of images in each multiplexed image.

[0088] The concept of an observer-based function based on light in space and time, or plenoptic function, was developed to represent visual stimuli as perceived by the visual system. The basic variables belonging to a plenoptic function include the three-dimensional (3D) coordinates (x, y, z) where the light is viewed, and the direction, described by the angle (θ, Φ), that the light travels to this viewing position. Together with the wavelength λ of the light and the observation time t, these form the plenoptic function. P(x,y,z,θ,Φ,λ,t)

[0089] Instead of a plenoptic function, the radiance along a ray in 3D space at a point can be used, and a specific direction can be represented by a light field. The definition of a light field can be synonymous with the definition of a plenoptic function. A light field can be described as a 5D function, radiance flowing through all points in all possible directions. For static light fields, the light field can be represented as a scalar function. L(x,y,z,θ,Φ) where (x, y, z) represent radiance as a function of position, and the direction of light travel is described by (θ, Φ). A viewer of an object in the 3D real world is exposed to an infinite number of views, or a continuously distributed light field. To substantially replicate this, this disclosure describes a direct projection light field display that subsamples the continuously distributed light field into a finite number of views, or multiple views, to approximate the light field. The output of a direct projection light field display is a light field, which is a 3D representation of the continuously distributed light field based on a finite number of views, with an angular resolution that exceeds that of the human eye.

[0090] A multiplexed light field display is achieved by temporally or spatially multiplexing, or overlapping, two or more images. A spatially multiplexed display can be described as using lenses, motors, or other equivalent optical or mechanical components in combination with a light source to display separate views at different viewing angles. A spatially multiplexed light field display can generate unique images for multiple viewers or viewing positions. By using the same hardware to generate two or more images projected at different positions or angles and changing the image positions at a rate faster than the viewer can distinguish them, the number of pixels in the light field display can effectively be multiplied by the number of projected image positions that can be achieved by the multiplexed system. Based on the minimum rate at which the human eye cannot distinguish approximately 30 Hz, the minimum frame rate for a display is 24 Hz to 30 Hz. Therefore, for a multiplexed system, the frame rate must increase by the same factor as the number of multiplexed frames per frame increases. In one example, if a typical display refreshes at 30 Hz, a multiplexed image with four output light field images, each at a different location, would require a total frame refresh rate of 120 Hz, with each of the four output light fields having a refresh rate of at least 30 Hz. Thus, by rapidly changing the projected image position of each projector in a light field projector using multiplexing components, pixel density can be significantly increased with the same hardware.

[0091] To achieve multiplexing and multiplexed images using the projector of the present invention, at least one multiplexing optical element is added to one or more optical components in the projector to shift the light beam emitted by the LED or its downstream optical path by a desired amount, at a rate fast enough that the multiplexed image is indistinguishable to the human eye. To generate a multiplexed image having two different light field images, the projector uses the multiplexing optical element to change the projection angle of the light beam from a first position where the first image is projected to a second or subsequent position by a distance of less than one pixel width relative to the first image position and at a desired angle relative to the projection direction of the first image. This results in two images being projected at two different positions, and this composite image is called a multiplexed image. It is understood that a multiplexing projector can use one or more multiplexing devices to generate three or more light field images, resulting in a multiplexed image composed of three or more angularly offset light field images.

[0092] Various types of multiplexing devices can be used. Preferably, the multiplexing device is either a multiplexing actuator, an optical component capable of the quadratic electro-optic effect, also known as the Kerr effect, or an optical component that can be deformed to adjust the light path direction. Various types of actuators can be used as multiplexing devices to mechanically shift the projector's optical components to adjust the light path. These include, but are not limited to, piezoelectric actuators, electrothermal actuators, magnetic actuators, electrostatic actuators, or shape-memory alloy-based actuators. A multiplexing device capable of producing the Kerr effect is a component made of a material that can adjust its refractive index in response to an applied electric field. Various materials capable of producing the quadratic electro-optic effect are known, and identical or similar multiplexed images can be obtained by using a single optical component from these materials in combination with a device that can generate the electric field necessary to adjust the refractive index of the material. The Kerr effect, also known as the quadratic electro-optic (QEO) effect, is the change in the refractive index of a material in response to an applied electric field, where the induced refractive index change is directly proportional to the square of the electric field rather than linearly varying with the electric field. While all materials exhibit the Kerr effect, certain liquids exhibit it more strongly than others. Adaptive optics, along with components capable of deforming deformable optics, can also be used in projectors to achieve deformation of optical elements that change the light path. Adaptive optics can also be used to manipulate wavefronts within optical systems. For example, a deformable optical component, such as a mirror, can correct the wavefront by changing its shape when an external control signal is applied. Some non-limiting examples of optical components in adaptive optics systems are deformable mirrors and wavefront sensors.

[0093] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0094] The use of the words "a" or "an" when used herein in conjunction with the word "comprising" can mean "one," but is also equivalent to meaning "one or more," "at least one," and "one or more."

[0095] As used herein, the terms "comprising," "having," "including," and "containing," and grammatical variations thereof, are inclusive or open-ended and do not exclude additional, unrecited elements and / or method steps. The term "consisting of," when used herein in connection with a composition, device, article, system, use, or method, excludes the presence of additional elements and / or method steps. Also, a composition, device, article, system, use, or method described herein as including particular elements and / or steps can, in certain embodiments, consist essentially of those elements and / or steps, and in other embodiments, the embodiment can consist of those elements and / or steps, whether or not they are specifically mentioned in those embodiments.

[0096] As used herein, the term "about" refers to about a + / - 10% variation from a particular value. It is to be understood that such a variation is always included in any particular value given herein, whether or not it is specifically referred to.

[0097] Descriptions of ranges herein are intended to mean that both the range and the individual values ​​falling within the range are of the same part as the numbers used to denote the range, unless otherwise indicated herein.

[0098] The use of example or exemplary terminology, such as "such as," "exemplary embodiment," "illustrative embodiment," and "for example," is intended to illustrate or illustrate aspects, embodiments, variations, elements, or features related to the invention and is not intended to limit the scope of the invention.

[0099] As used herein, the terms "connect" and "connected" refer to any direct or indirect physical coupling between elements or functions of the present disclosure. As such, these terms can be understood to refer to elements or functions that are partially or completely contained within, attached to, coupled to, positioned with, joined together, in communication with, or operatively associated with one another, even if other elements or features may be intervening between the elements or functions described as connected.

[0100] As used herein, the term "pixel" refers to a spatially distinct light-emitting mechanism used to construct a display.

[0101] As used herein, the term "subpixel" refers to a structure having a light-emitting element housed within an optical microcavity. The optical microcavity is operatively associated with a plurality of reflective surfaces to substantially collimate, manipulate, or condition light. At least one of the reflective surfaces is a light-propagating reflective surface connected to the optical microcavity to propagate light out of the microcavity. The present disclosure provides individually addressable red, green, and blue (RGB) subpixels. The size of the subpixels as described in the present disclosure ranges from the nanoscale to several microns, which is much smaller than pixel sizes previously known in the art.

[0102] As used herein, the term "light field" at a basic level refers to a function that describes the amount of light flowing in all directions through a point in open space. A light field thus describes the radiance as a function of the position and direction of light in free space. Light fields can be synthetically generated by various rendering processes, or they can be captured from a light field camera or an array of light field cameras.

[0103] As used herein, the term "light field display" refers to a device that reconstructs a light field from a finite number of light field radiance samples input to the device. The radiance samples include red, green, and blue (RGB) color components from LEDs of the same color. In a light field display, the reconstruction of the light field can also be understood as a mapping from a four-dimensional space to a single RGB color. The four dimensions include the vertical and horizontal dimensions of the display and two dimensions representing the directional component of the light field. The light field can be defined as the following function: LF:(x,y,u,v)→(r,g,b) Light Field LF(x f ,y f ,u,v) at a fixed position (x f ,y f ) represents a two-dimensional (2D) image called an "element image." An element image is a fixed position (x f ,y f ) is a directional image of the light field from a light source. When multiple elemental images are concatenated side by side, the resulting image is called an "integral image." An integral image can be understood as the entire light field required for a light field display.

[0104] As used herein, the term "LFP lens" refers to a light field projection lens, which serves to collimate incident light.

[0105] As used herein, the acronym "FWHM" refers to "Full-Width at Half Maximum," which describes the measure of a function given by the difference between the two extreme values ​​of the independent variable where the dependent variable is equal to half its maximum value.

[0106] As used herein, the term "hogel" is an alternative term for holographic pixel, which is a cluster of traditional pixels with directional control. An array of hogels can generate a light field. Just as pixels define the spatial resolution of a two-dimensional display, holographic pixels or hogels define the spatial resolution of a three-dimensional display.

[0107] As used herein, the term "hogel pitch" refers to the distance from the center of one hogel to the center of an adjacent hogel.

[0108] As used herein, the term "optical mirror" refers to an object that reflects light in a range of wavelengths such that the reflected light retains many or most of the detailed physical properties of the original light. This can also be called specular reflection. Two or more mirrors aligned exactly parallel and facing each other can produce an infinite regress of reflection, also called the infinite mirror effect.

[0109] As used herein, the term "pixel pitch" refers to the distance from the center of one pixel to the center of an adjacent pixel.

[0110] As used herein, the term "pixel array" refers to the arrangement of pixels within a hogel.

[0111] As used herein, the term "wavelength" is a measure of the distance between two identical peaks (high points) or valleys (low points) of a wave, which is a repeating pattern of propagating energy such as light or sound.

[0112] As used herein, the term "simulation" refers to a computer model of an object or physical phenomenon. Simulations can be used, for example, for research purposes or to develop and refine build specifications. Various simulation techniques can be used, including, but not limited to, Finite Difference Time Domain (FDTD), ray tracing, Finite Element Analysis (FEA), and Finite Element Method (FEM).

[0113] As used herein, one or more parameters of a light field display include one or more of hogel pitch, pixel pitch, and focal length. The term pixel refers to a set of red, green, and blue subpixels. Pixel pitch is defined as the distance from the center of one pixel to the center of an adjacent pixel. As used herein, pixel array refers to the arrangement of pixels within a hogel. A hogel is an alternative term for a holographic pixel and is a cluster of conventional pixels with directional control. An array of hogels can generate a light field. Therefore, hogel pitch is defined as the distance from the center of one hogel to the center of an adjacent hogel. The field of view of a lens is defined by its focal length. Generally, the shorter the focal length, the wider the field of view. Note that the focal length is measured from the rear principal surface of the lens. The rear principal surface of a lens is rarely located at the mechanical back surface of the imaging lens. For this reason, system approximations and mechanical designs are typically calculated using computer simulations.

[0114] It is contemplated that all embodiments of the compositions, devices, articles, methods, and uses disclosed herein can be implemented by one of ordinary skill in the art either as is or by making modifications or equivalents without departing from the scope of the invention.

[0115] This specification describes a multiplexed light field projector that can realize a multiplexed light field display. The light field projector of the present invention can be used for multi-view, autostereoscopic, and high-angular-resolution light field displays. The light field display can also be viewed with both horizontal and vertical parallax. To improve upon current direct-projection light field display designs, this disclosure describes a projector specifically designed to build a multiplexed light field display to minimize pixel size and optimize display viewing parameters. This disclosure describes a lens design for light field projection (LFP) that leverages an optical system design to fill the entire front aperture of the body. Images generated by LFP lenses have a small divergence to allow projected images to overlap at the edges while allowing the subsequent optical architecture to generate the light field.

[0116] In normal operation, a light field projector receives light from one or more light sources and directs the light onto a pixel forming device using illumination optics within a projection optical system. The illumination optics can include, but are not limited to, a plano-convex lens, a dichroic mirror, a microlens array, a meniscus lens, a bi-convex lens, a single prism, or a folded prism. The pixel forming device converts the light coming from the illumination optics into a plurality of pixels. Light entering the pixel forming device is emitted from one or more light-emitting diodes (LEDs) within the illumination optical system and converted by the pixel forming device into a pixel array. The light from the pixel forming device then travels through a series of projection optics or projection components within the magnification optics, which serve to magnify the pixel array coming from the pixel forming device to form an enlarged pixel array. The magnification optics can be a projection doublet, a bi-convex lens, or other suitable optical component. The light from the projection optical system is then collimated in a collimating optical system to generate a collimated projected image. This involves taking a small image with a high pixel density and collimating the light, thereby producing an array of light beams with minimal, low, or no divergence. Because display lenses in projectors work best with little or no divergent incident light, collimating optics provide substantially collimated light to the display lenses in the display optics.

[0117] Conventional projectors generally achieve a resolution of approximately 1 pixel / mm, assuming a typical projected image size and distance to the room size or projection screen. 2 The projectors described herein are configured to produce large images with a coarse pixel density of approximately 10,000 pixels per mm. 2A much higher pixel density is achieved. The projection optics in this system are designed with a low magnification to overcome the tiling effect resulting from images generated by multiple projection devices. However, the magnification is not so significant that it interferes with pixel density. To build a light field display, the light field image outputs from multiple projectors are tiled together to produce a complete light field image. If there is a light field image gap between two projected images, a dark seam or interface where no light is projected may occur between the light field image outputs from each light device, creating a picket fence effect or tiling effect at the seam between the outputs from each projection device. The projector described herein overcomes the tiling problem by magnifying the image formed by the display device. Thus, by magnifying the image from the display device, the image at the output of the display optics lens is at least as large as the physical dimensions of the projector itself, ensuring overlap between the light field images generated by the array of projectors. The projection optics magnifies the light enough to overcome the tiling effect but without sacrificing pixel density. Thus, the high pixel density required for light field displays is achieved. The human eye, assuming good visual acuity and optimal viewing conditions, can only resolve pixel sizes of approximately 35 microns. Without a display lens, the pixel density achieved by the projectors described herein is on the order of 10 microns. Thus, images produced by the projectors of the present invention appear fluid, sharp, and unpixelated.

[0118] Light field displays known in the art typically require very bright projectors. One advantage of the light field projectors described herein is the reduced brightness requirements of the projector itself. The reduced brightness requirements of the projectors described herein are achieved by controlling the angular distribution of light through the design of the light field projector's optical system and applying a point spread function to the light beam. The ability to control the angular distribution of light and the applied point spread function ensures efficient light output with minimal losses. The reduced brightness requirements allow the use of smaller LEDs without internal cooling requirements, reducing the overall footprint of the device. When two or more light field projectors designed herein are used in combination with each other, tighter packaging densities can also be achieved.

[0119] Projector array-based displays can pose design challenges, not least due to the need to contain many closely-spaced, precisely aligned projectors in a small space. Orienting the optics within the projector base as described herein, combined with multiple optics for light collimation and diffusion, can achieve reduced pixel size, minimal projector footprint, fully scalable designs to larger displays, reduced tolerance constraints, and reduced chromatic aberrations with multi-optic light field display designs.

[0120] Various features of the light field projector will become apparent from the following detailed description, taken in conjunction with the diagrams in the various drawings. The design parameters, design methods, construction, and use of the light field projectors and structures disclosed herein are described with reference to various examples, which represent embodiments that are not intended to limit the scope of the inventions described and claimed herein. Those skilled in the art to which the invention pertains will appreciate that there may be other variations, examples, and embodiments of the invention not disclosed herein that can be implemented in accordance with the teachings of the present disclosure without departing from the scope of the present disclosure.

[0121] Light field displays require the smallest possible pixel size to increase the spatial and / or directional resolution of the display. For light field projectors used in direct projection light field displays, the pixel size is determined by the projected image size of the active area at the projector's focal length. Here, the overall space of a single projector must be the same as the image dimensions. If the entire space occupied by the pixels is filled, the spacing between pixels, or pixel pitch, is equal to the pixel size. The pixel pitch and hogel pitch parameters determine the spatial resolution and depth of field of the display, and therefore the user experience. The smaller the hogel pitch, the higher the spatial resolution of the light field display. The more pixels in a hogel, the higher the depth of field of the display. Increasing the pixel density allows designers to design different light field displays for different applications. For example, increasing the hogel pitch and decreasing the spatial resolution can increase the depth of field.

[0122] To achieve the smallest pixel size, the space occupied by a single projector must be minimized. One way to minimize the projector footprint is through direct mounting. Here, as shown in Figure 16, the projector bodies in a projector array are directly mounted to the chassis, leaving minimal space between adjacent projectors. In this case, the projector footprint is as close as possible to the dimensions of the display device with which it is used. Direct mounting eliminates the mechanical means of adjusting the projector's alignment within the display, necessitating a digital projector correction method to provide an additional number of correction pixels outside of each projector's active area. These correction pixels allow the projector frame to be offset in both the x and y dimensions of the display device, correcting for misalignment in six degrees of freedom.

[0123] The number of pixels required for correction is directly related to the mechanical design of the projector array system. Mounting projectors with the tightest possible tolerances minimizes the number of correction pixels required. One example of digital correction is to divide the pixels in a single projector's frame into a light field image, overlapping pixels, and a correction buffer. This correction buffer is determined based on the set tolerance of the projector array and the maximum pixel misalignment. For example, if the maximum resolution of the projected image is 2048 x 1080, the projected image pixels can be divided so that the projector's light field image has a resolution of 1944 x 1000, with 20 pixels overlapping with adjacent projectors. The overlapping pixels display overlapping data from adjacent projectors, with an intensity function applied to blend the tiled display. The resolution of the light field frame and overlapping pixels is 1984 x 1040 pixels. Also, the increased image size due to optical correction for distortion and chromatic aberrations must be taken into account. This 1984x1040 resolution image is offset from the center of the display device by 2048x1080 to allow for per-projector misalignment correction, corresponding to 64 pixels in the x direction and 40 pixels in the y direction. In this example, the maximum projector footprint is calculated as the resolution of the light field projector multiplied by the equivalent pixel size in the light field display.

[0124] This section outlines the calibration procedure for projectors and displays. First, a calibration file associated with the display's specified white point is generated for each projector by mapping the projector output through the display's full color gamut. Calibrating each projector modifies the LED voltage, current, and mixing ratio to achieve color uniformity across the display while ensuring that the intensity of each color step is within specified tolerances. Projector calibration can be performed with the projector installed in the display, or on each individual projector prior to installation using a calibrated imaging device such as a photometer, colorimeter, or digital single-lens reflex camera (DSLR). Optical corrections for distortion, warpage, or other projector-based quantities can be applied at this stage.

[0125] In the next step, the display optics are installed in the display system so that any intensity non-uniformities can be corrected. Depending on the number and optical quality of the optical components, this step may not be necessary. For light field projectors installed in the display, the projector's digital offset is determined and set before the display is characterized and corrected. A frame of the light field projector is illuminated within each projector, and the digital offset is automatically determined through an iterative process using a DSLR. Each projector requires a separate set of values. Once the offset values ​​are determined, additional pixels within the projector are illuminated, assigned to overlap with adjacent projectors. A default set of coefficients is assigned to each projector, with different coefficients recorded for outer edge projectors. These coefficients are then updated in an automated procedure to achieve the desired blending. The final step is calibration of the light field display, which is performed to adjust the pixel-to-pixel correspondence from projector pixels to light field pixels.

[0126] As mentioned above, multiplexing of a light field projector can be achieved by spatial or temporal multiplexing techniques. The purpose of this disclosure is to describe a multiplexing method for a light field projector. A multiplexed light field display is achieved by temporally or spatially multiplexing or overlapping two or more light field images generated by a single projector to provide multiple unique images to multiple viewers or viewing positions. A spatially multiplexed display can be described as using lenses, motors, or other equivalent optical or mechanical components in combination with a light source to display separate views at different viewing angles. In one embodiment, multiplexing can be achieved by adding an actuator device to the disclosed light field projector. An actuator can be defined as a mechanical and / or electrical component that moves an optical element in one or two dimensions to shift the light from the projector by a distance slightly smaller than the pixel size. This is referred to herein as a "multiplexing actuator."

[0127] FIG. 1 shows an isometric view of a light field projector. All optical components can be housed within a projector housing 60 or other housing or structure that secures the components. A light field image generated by a set of LEDs within the projection optics is projected through a collimating optics system 18, which includes a light field projection (LFP) lens. The illustrated light field projector also includes a flexible printed circuit (FPC) 130, also known as a light field projector flex cable, for connecting the light field projector and light source to the driving electronics. The body of the light field projector serves to house and secure the optical components within the projector. Alternative configurations for the projector body can include one or more single surfaces or structures that can secure or hold the optical components in place.

[0128] FIG. 2A illustrates one embodiment of a light field projector configuration with multiplexing. FIG. 2A shows the arrangement of projection optics 14 as shown, with the light ray paths directed to collimating optics 18. The collimating optics 18 is comprised of a light field projection (LFP) lens 98. In operation, a light field projector receives light from one or more light sources and directs the light toward a display device using illumination optics. A pixel-forming device converts the light from the illumination optics into multiple pixels. Light entering the display device originates from one or more light-emitting diodes (LEDs) in the illumination optics and is converted by the display device into a pixel array. The light from the display device then travels through a series of projection optics, which function to magnify the image from the display device. The light from the projection optics is then collimated. The collimating optics form a small image with high pixel density, collimating the light and producing a light beam with minimal, low, or no divergence. Also included in FIG. 2A is display optics 22. Display optics, which include a display lens, function optimally with little or no divergent incident light. Therefore, collimating optics provide substantially collimated light to the display lens within display optics 22. In this embodiment, light emitted from a green LED 10a, a red LED 10b, and a blue LED 10c is directed toward projection optics 14. The illustrated projection optics 14 includes a series of three plano-convex lenses 80a, 80b, and 80c, one for each of LEDs 10a, 10b, and 10c, through which light from each LED is directed. The three separate light paths resulting from the three LEDs 10a, 10b, and 10c are then directed through a series of dichroic mirrors 66a, 66b, where they converge to form a single light path. Dichroic mirror 66a transmits the green light from LED 10a and reflects the red light from LED 10b. Similarly, dichroic mirror 66b transmits the green and red light from LEDs 10a and 10b and reflects the blue light from LED 10c, thereby combining the red, green, and blue light to form a single light path.The light then passes through the microlens array 68, the meniscus lens 70, the first bi-convex lens 72a, and the folding prism 74. The ray path through the folding prism 74 is directed to the pixel forming device 76, which may be, for example, a liquid crystal on silicon (LCOS) panel, a digital micromirror device (DMD), or other display device. The ray path then passes back through the folding prism 74 to the second bi-convex lens 72b and on to a series of projection doublets 78a and 78b. The ray path then passes to the collimating optics 18, which in this embodiment comprises an LFP lens 98. The LFP lens 98 serves to collimate the incident light. The ray path continues to the display optics 22. The projected multiplexed light field output 112 from the display optics 22 includes two separate light field images, shown as a first set of rays indicated by solid lines and a second set of rays indicated by dashed lines. Together, these comprise the multiplexed light field output 112. Note that in this configuration, the display optics 22 may be any suitable display optics, including, but not limited to, a single lens, a lens array, a pinhole array, a metasurface, or a metalens. Multiplexing can be achieved by shifting the LFP lens 98 along the second axis 116 or the third axis 122 using a multiplexing actuator programmed to shift the incident pixels by, for example, a quarter-integer or half-integer pixel value corresponding to the corresponding frame, to generate additional pixels in one direction based on the design. Multiplexing can also be achieved by a multiplexing device with actuators shifting the LFP lens 98 along the second axis 116 and the third axis 122 by a quarter-integer or half-integer pixel value in each direction. The end of each movement corresponds to a frame, increasing the effective pixels in both directions. Multiplexing can also be achieved by deforming the LFP lens 98 or by manipulating the refractive index of the material, effectively improving resolution in both directions.

[0129] FIG. 2B shows another embodiment of a light field projector configuration with multiplexing. FIG. 2B shows the arrangement of the projection optics 14 as shown, with the ray paths directed to the collimating optics 18. The collimating optics 18 is comprised of an LFP lens 98. Also included in FIG. 2B is the display optics 22. The projection optics 14 and collimating optics 18 are housed within the body of the projector, as shown in FIG. 1. In this embodiment, light emitted from a green LED 10a, a red LED 10b, and a blue LED 10c is directed to the projection optics 14. The projection optics 14 shown includes a series of three plano-convex lenses 80a, 80b, and 80c, one for each of the LEDs 10a, 10b, and 10c, through which the light from each LED is directed. The three separate light beam paths from the three LEDs 10a, 10b, and 10c are then directed through a series of dichroic mirrors 66a and 66b, where they converge to form a single light beam path. The dichroic mirror 66a transmits the green light from LED 10a and reflects the red light from LED 10b. Similarly, the dichroic mirror 66b transmits the green and red light from LEDs 10a and 10b and reflects the blue light from LED 10c. This converges the red, green, and blue light to form a single light beam path. The light then passes through a microlens array 68, a meniscus lens 70, a first biconvex lens 72a, and a folding prism 74, in that order. The light beam path through the folding prism 74 is directed to a pixel forming device 76. The pixel forming device 76 can be, for example, a liquid crystal on silicon (LCOS) panel, a digital micromirror device (DMD), or other display device. The ray path then passes back through the folding prism 74 to the second bi-convex lens 72b and on to a series of projection doublets 78a and 78b. The ray path then passes to the collimating optics 18, which in this embodiment comprises an LFP lens 98. The LFP lens 98 serves to collimate the incident light. The ray path continues to the display optics 22.The multiplexed light field output 112 projected from the display optics 22 includes two separate light field images, shown as a first set of solid rays and a second set of dashed rays, which together comprise the multiplexed light field output 112. Note that in this configuration, the display optics 22 may be any suitable display optical component, including, but not limited to, a single lens, a lens array, a pinhole array, a metasurface, or a metalens. FIG. 2B illustrates one multiplexing embodiment in which the multiplexer moves the LFP lens 98 in the positive z direction along the first axis 114, slightly increasing the divergence of the pixels in the projected image and increasing the size of the projected image at the imaging plane by an amount equivalent to, for example, a quarter-integer or half-integer pixel value shift. Similarly, the multiplexer can move the LFP lens 98 in the negative z direction to reduce the divergence, producing a smaller projected image at the imaging plane, depending on the spatial constraints of the design. This movement can be achieved, for example, by a multiplexing actuator.

[0130] FIG. 2C illustrates one embodiment of a light field projector configuration with multiplexing. FIG. 2C shows the arrangement of the projection optics 14 as shown, with the ray paths directed to the collimating optics 18. The collimating optics 18 is comprised of an LFP lens 98. Also included in FIG. 2C is the display optics 22. The projection optics 14 and collimating optics 18 are housed within the body of the projector, as shown in FIG. 1. In this embodiment, light emitted from a green LED 10a, a red LED 10b, and a blue LED 10c is directed toward the projection optics 14. The illustrated projection optics 14 includes a series of three plano-convex lenses 80a, 80b, and 80c, one for each of the LEDs 10a, 10b, and 10c, through which the light from each LED is directed. The three separate light beam paths from the three LEDs 10a, 10b, and 10c are then directed through a series of dichroic mirrors 66a and 66b, where they converge to form a single light beam path. The dichroic mirror 66a transmits the green light from LED 10a and reflects the red light from LED 10b. Similarly, the dichroic mirror 66b transmits the green and red light from LEDs 10a and 10b and reflects the blue light from LED 10c. This converges the red, green, and blue light to form a single light beam path. The light then passes through a microlens array 68, a meniscus lens 70, a first biconvex lens 72a, and a folding prism 74, in that order. The light beam path through the folding prism 74 is directed to a pixel forming device 76. The pixel forming device 76 can be, for example, a liquid crystal on silicon (LCOS) panel, a digital micromirror device (DMD), or other display device. The ray path then passes back through the folding prism 74 to the second bi-convex lens 72b and on to a series of projection doublets 78a and 78b. The ray path then passes to the collimating optics 18, which in this embodiment comprises an LFP lens 98. The LFP lens 98 serves to collimate the incident light. The ray path continues to the display optics 22.The multiplexed light field output 112 projected from the display optics 22 includes two separate light field images, shown as a first set of solid rays and a second set of dashed rays, which together comprise the multiplexed light field output 112. Note that in this configuration, the display optics 22 may be any suitable display optical component, including, but not limited to, a single lens, a lens array, a pinhole array, a metasurface, or a metalens. In this embodiment, the pixel forming devices 76 may be, for example, a liquid crystal on silicon (LCOS) panel, a digital micromirror device (DMD), or other display device that can be operated using a multiplexing actuator or other suitable component or method. As shown in FIG. 2C , to achieve multiplexing, a multiplexing device, such as a multiplexing actuator, may be used to shift the pixel forming devices 76 along a first axis 114, a second axis 116, or a combination of both axes. Manipulation of the position of pixel forming device 76 is synchronized with the input image so that the device movement provides increased resolution in one or two dimensions.

[0131] FIG. 2D shows one embodiment of a light field projector configuration with multiplexing. It shows the layout of the projection optics 14, where the light paths are directed to the collimating optics 18. The collimating optics 18 is comprised of an LFP lens 98. Also included in FIG. 2D is the display optics 22. The projection optics 14 and collimating optics 18 are housed within the projector body, as shown in FIG. 1. In this embodiment, light emitted from a green LED 10a, a red LED 10b, and a blue LED 10c is directed to the projection optics 14. The illustrated projection optics 14 includes a series of three plano-convex lenses 80a, 80b, and 80c, one for each of the LEDs 10a, 10b, and 10c, through which the light from each LED is directed. The three separate light paths resulting from the three LEDs 10a, 10b, and 10c are then directed through a series of dichroic mirrors 66a and 66b and combined to form a single light path. Dichroic mirror 66a transmits the green light from LED 10a and reflects the red light from LED 10b. Similarly, dichroic mirror 66b transmits the green and red light from LEDs 10a and 10b and reflects the blue light from LED 10c. This causes the red, green, and blue light to merge into a single light path. The light then passes through microlens array 68, meniscus lens 70, first biconvex lens 72a, and folding prism 74. The light path through folding prism 74 is directed toward pixel forming device 76, which may be, for example, a liquid crystal on silicon (LCOS) panel, a digital micromirror device (DMD), or other display device. The light path then passes back through folding prism 74 to second biconvex lens 72b and onto a series of projection doublets 78a and 78b. The ray path then travels to collimating optics 18, which in this embodiment comprises an LFP lens 98. The LFP lens 98 serves to collimate the incident light. The ray path continues to display optics 22. The projected multiplexed light field output 112 from display optics 22 includes two separate light field images, shown as a first set of rays indicated by solid lines and a second set of rays indicated by dashed lines.Together, these comprise the multiplexed light field output 112. Note that in this configuration, the display optics 22 may be any suitable display optics, including, but not limited to, a single lens, a lens array, a pinhole array, a metasurface, or a metalens. In this embodiment, multiplexing is achieved by using a multiplexing device, such as a multiplexing actuator, to manipulate the angle and / or position of the folded prism 74 along the second axis 116, the third axis 122, or both axes in synchronization with the input frame to increase the effective resolution in one or both directions. The multiplexing actuator may be, but is not limited to, a piezoelectric actuator, an electrothermal actuator, a magnetic actuator, an electrostatic actuator, or a shape memory alloy-based actuator.

[0132] FIG. 2E shows one embodiment of a light field projector configuration with multiplexing. It shows the projection optics 14, where the light paths are directed to the collimating optics 18. The collimating optics 18 is comprised of an LFP lens 98. Also included in FIG. 2E is the display optics 22. The projection optics 14 and collimating optics 18 are housed within the projector body, as shown in FIG. 1. In this embodiment, light emitted from a green LED 10a, a red LED 10b, and a blue LED 10c is directed toward the projection optics 14. The illustrated projection optics 14 includes a series of three plano-convex lenses 80a, 80b, and 80c, one for each of the LEDs 10a, 10b, and 10c, through which the light from each LED is directed. The three separate light paths resulting from the three LEDs 10a, 10b, and 10c are then directed through a series of dichroic mirrors 66a and 66b and combined to form a single light path. Dichroic mirror 66a transmits the green light from LED 10a and reflects the red light from LED 10b. Similarly, dichroic mirror 66b transmits the green and red light from LEDs 10a and 10b and reflects the blue light from LED 10c. This causes the red, green, and blue light to merge into a single light path. The light then passes through microlens array 68, meniscus lens 70, first biconvex lens 72a, and folding prism 74. The light path through folding prism 74 is directed toward pixel forming device 76, which may be, for example, a liquid crystal on silicon (LCOS) panel, a digital micromirror device (DMD), or other display device. The light path then passes back through folding prism 74 to second biconvex lens 72b and onto a series of projection doublets 78a and 78b. The ray path then travels to collimating optics 18, which in this embodiment comprises an LFP lens 98. The LFP lens 98 serves to collimate the incident light. The ray path continues to display optics 22. The projected multiplexed light field output 112 from display optics 22 includes two separate light field images, shown as a first set of rays indicated by solid lines and a second set of rays indicated by dashed lines.Together, these comprise the multiplexed light field output 112. Note that in this configuration, the display optics 22 can be any suitable display optics, including, but not limited to, a single lens, a lens array, a pinhole array, a metasurface, or a metalens. FIG. 2E illustrates one embodiment of the disclosed light field projector configuration with multiplexing. In this embodiment, the multiplexer 124 is collinear with the folded prism 74 and the pixel forming device 76. The multiplexer 124 is a mechanical device that shifts the position and / or angle of the folded prism 74 in this case to shift the optical path and generate one or more additional light fields from the projector. Controlling the movement of the multiplexer 124 allows the creation of additional light fields at speeds and with angular resolutions beyond the resolution of the human eye, such that the viewer cannot detect this movement. This allows the multiplexer 124 to shift both components in 1D or 2D in the x, y, z, or any combination thereof. The multiplexing device 124 can be, but is not limited to, a piezoelectric actuator, an electrothermal actuator, a magnetic actuator, an electrostatic actuator, or a shape memory alloy based actuator.

[0133] FIG. 2F shows one embodiment of a light field projector configuration with multiplexing. FIG. 2F shows the arrangement of the projection optics 14 as shown, with the ray paths directed to the collimating optics 18. The collimating optics 18 is comprised of an LFP lens 98. Also included in FIG. 2F is the display optics 22. The projection optics 14 and collimating optics 18 are housed within the body of the projector, as shown in FIG. 1. In this embodiment, light emitted from a green LED 10a, a red LED 10b, and a blue LED 10c is directed toward the projection optics 14. The projection optics 14 shown includes a series of three plano-convex lenses 80a, 80b, and 80c, one for each of the LEDs 10a, 10b, and 10c, through which light from each LED is directed. The three separate light beam paths from the three LEDs 10a, 10b, and 10c are then directed through a series of dichroic mirrors 66a and 66b, where they converge to form a single light beam path. The dichroic mirror 66a transmits the green light from LED 10a and reflects the red light from LED 10b. Similarly, the dichroic mirror 66b transmits the green and red light from LEDs 10a and 10b and reflects the blue light from LED 10c. This converges the red, green, and blue light to form a single light beam path. The light then passes through a microlens array 68, a meniscus lens 70, a first biconvex lens 72a, and a folding prism 74, in that order. The light beam path through the folding prism 74 is directed to a pixel forming device 76. The pixel forming device 76 can be, for example, a liquid crystal on silicon (LCOS) panel, a digital micromirror device (DMD), or other display device. The ray path then passes back through the folding prism 74 to the second bi-convex lens 72b and on to a series of projection doublets 78a and 78b. The ray path then passes to the collimating optics 18, which in this embodiment comprises an LFP lens 98. The LFP lens 98 serves to collimate the incident light. The ray path continues to the display optics 22.The multiplexed light field output 112 projected from the display optics 22 includes two separate light field images, shown as a first set of solid rays and a second set of dashed rays, which together comprise the multiplexed light field output 112. Note that in this configuration, the display optics 22 may be any suitable display optical component, including, but not limited to, a single lens, a lens array, a pinhole array, a metasurface, or a metalens. In this embodiment, the multiplexer 124 is a multiplexing actuator connected to the folded prism 74 and the pixel forming device 76. The multiplexer 124 shifts these components by a desired amount to increase the effective resolution of the projection system in the x, y, z directions, or any combination thereof.

[0134] FIG. 2G shows one embodiment of a light field projector configuration with multiplexing. FIG. 2G shows the arrangement of the projection optics 14 as shown, with the ray paths directed to the collimating optics 18. The collimating optics 18 is comprised of an LFP lens 98. Also included in FIG. 2G is the display optics 22. The projection optics 14 and collimating optics 18 are housed within the body of the projector, as shown in FIG. 1. In this embodiment, light emitted from a green LED 10a, a red LED 10b, and a blue LED 10c is directed toward the projection optics 14. The illustrated projection optics 14 includes a series of three plano-convex lenses 80a, 80b, and 80c, one for each of the LEDs 10a, 10b, and 10c, through which the light from each LED is directed. The three separate light beam paths from the three LEDs 10a, 10b, and 10c are then directed through a series of dichroic mirrors 66a and 66b, where they converge to form a single light beam path. The dichroic mirror 66a transmits the green light from LED 10a and reflects the red light from LED 10b. Similarly, the dichroic mirror 66b transmits the green and red light from LEDs 10a and 10b and reflects the blue light from LED 10c. This converges the red, green, and blue light to form a single light beam path. The light then passes through a microlens array 68, a meniscus lens 70, a first biconvex lens 72a, and a folding prism 74, in that order. The light beam path through the folding prism 74 is directed to a pixel forming device 76. The pixel forming device 76 can be, for example, a liquid crystal on silicon (LCOS) panel, a digital micromirror device (DMD), or other display device. The ray path then passes back through the folding prism 74 to the second bi-convex lens 72b and on to a series of projection doublets 78a and 78b. The ray path then passes to the collimating optics 18, which in this embodiment comprises an LFP lens 98. The LFP lens 98 serves to collimate the incident light. The ray path continues to the display optics 22.The multiplexed light field output 112 projected from the display optics 22 includes two separate light field images, shown as a first set of solid rays and a second set of dashed rays, which together comprise the multiplexed light field output 112. In this configuration, the display optics 22 can be any suitable display optics, including, but not limited to, a single lens, a lens array, a pinhole array, a metasurface, or a metalens. FIG. 2G illustrates an embodiment of a light field projector configuration with multiplexing. In this embodiment, the second bi-convex lens 72b is manipulated using a multiplexing actuator or other suitable component or method. In particular, the second bi-convex lens 72b can be configured to be shifted, for example, along the second axis 116, the third axis 122, or any combination thereof, with each shifted endpoint increasing the effective resolution of the output device for a corresponding frame. In another embodiment, the second biconvex lens 72b can be fabricated from a material capable of changing its refractive index in response to an applied electric field and can be connected to a multiplexer that can change the electric field applied to the second biconvex lens 72b. This can shift the focus of the element 72b by a calibrated amount at a frequency corresponding to the input frame rate to increase the effective resolution. In embodiments in which the multiplexer is realized by deformation of an optical element, the optical element can be made from a deformable or elastic material. The deformation here changes the curvature of the lens surface. Suitable deformable or elastic materials for forming the optical element include, but are not limited to, polymers consisting of layers of the elastomeric poly(ethylene-octene) and the glassy polymer polycarbonate; two immiscible liquids, such as ultrapure water and polydimethylsiloxane; and a silicone elastomer lens coupled to a dielectric elastomer actuator. The deformation can be induced by applying a physical force to the optical element to deform the material.Deformation can be achieved by, but is not limited to, piezoelectric transducers, thermal actuation, liquid crystals, electrowetting, tunable acoustic gradient index, and dielectric elastomer actuation. In the simplest applications, the deformation can be binary, such as a first lens curvature in a first configuration and a second lens curvature in a second configuration. Any power source that can be connected to a multiplexer to generate the appropriate voltages can be used in combination with the deformable optical component.

[0135] In another embodiment, multiplexing is achieved by changing the refractive index of an optical component. In the first case, applying a voltage to the material of the optical component causes a change in its refractive index. The change in refractive index can be controlled in a calibrated manner based on the applied voltage. This change in refractive index corresponds to a refraction that further results in an angular output different from the original output. In the simplest application, the change in refractive index of the optical component can be binary, or calibrated binary. Here, applying a first voltage causes a first refractive index, and applying a second voltage causes a second refractive index. In another case, a voltage difference can be applied to the material of the optical component so that the material has resistive properties. In this case, a voltage drop is created between two electrodes attached to the optical component, creating a refractive index gradient in the material. This can be beneficial because it can cause a change in angular output across the surface, resulting in an angular gradient for pixels incident on the optical component. Suitable optical component materials can be semiconductor materials with electrically tunable optical properties, including, but not limited to, molybdenum disulfide (MoS2) monolayers, tantalum pentoxide (Ta2O5) and silicon dioxide (SiO2) layers, indium tin oxide (ITO) metasurfaces with aluminum gates, metasurfaces combined with dielectric spacers made of graphene and amorphous silicon, and van der Waals heterostructures made of hBN / MoS2 / hBN. Any power source that can be connected to the multiplexer to generate the appropriate voltage can be used in combination with optical components with tunable refractive index.

[0136] FIG. 2H shows one embodiment of a light field projector configuration with multiplexing. FIG. 2H shows the arrangement of the projection optics 14 as shown, with the ray paths directed to the collimating optics 18. The collimating optics 18 is comprised of an LFP lens 98. Also included in FIG. 2H is the display optics 22. The projection optics 14 and collimating optics 18 are housed within the body of the projector, as shown in FIG. 1. In this embodiment, light emitted from a green LED 10a, a red LED 10b, and a blue LED 10c is directed toward the projection optics 14. The projection optics 14 shown includes a series of three plano-convex lenses 80a, 80b, and 80c, one for each of the LEDs 10a, 10b, and 10c, through which the light from each LED is directed. The three separate light beam paths from the three LEDs 10a, 10b, and 10c are then directed through a series of dichroic mirrors 66a and 66b, where they converge to form a single light beam path. The dichroic mirror 66a transmits the green light from LED 10a and reflects the red light from LED 10b. Similarly, the dichroic mirror 66b transmits the green and red light from LEDs 10a and 10b and reflects the blue light from LED 10c. This converges the red, green, and blue light to form a single light beam path. The light then passes through a microlens array 68, a meniscus lens 70, a first biconvex lens 72a, and a folding prism 74, in that order. The light beam path through the folding prism 74 is directed to a pixel forming device 76. The pixel forming device 76 can be, for example, a liquid crystal on silicon (LCOS) panel, a digital micromirror device (DMD), or other display device. The ray path then passes back through the folding prism 74 to the second bi-convex lens 72b and on to a series of projection doublets 78a and 78b. The ray path then passes to the collimating optics 18, which in this embodiment comprises an LFP lens 98. The LFP lens 98 serves to collimate the incident light. The ray path continues to the display optics 22.The multiplexed light field output 112 projected from the display optics 22 includes two separate light field images, shown as a first set of solid rays and a second set of dashed rays, which together comprise the multiplexed light field output 112. In this configuration, the display optics 22 can be any suitable display optics, including, but not limited to, a single lens, a lens array, a pinhole array, a metasurface, or a metalens. FIG. 2H illustrates a multiplexing technique in which the position of the first projection doublet 78 a or the second projection doublet 78 b is manipulated along a first axis 114 by a multiplexer. In one embodiment, moving one of the projection doublets changes the focus of the projection system, increasing or decreasing the magnification of the projected image. For example, if moving element 78 a increases the image size by a quarter-integer or half-integer number of pixels relative to the input frame, the multiplexing effect occurs in both dimensions, increasing the effective resolution. Since small movements are required, this can be achieved by using small piezoelectric transducers.

[0137] FIG. 2I shows one embodiment of a light field projector configuration with multiplexing. FIG. 2I shows the layout of the projection optics 14 as shown, with the ray paths directed to the collimating optics 18. FIG. 2I also includes an additional optical component, referred to herein as a multiplexing layer 118, positioned immediately prior to the display optics 22. The projection optics 14 and collimating optics 18 are housed within the projector body, as shown in FIG. 1. In this embodiment, light emitted from a green LED 10a, a red LED 10b, and a blue LED 10c is directed toward the projection optics 14. The illustrated projection optics 14 includes a series of three plano-convex lenses 80a, 80b, and 80c, one for each of the LEDs 10a, 10b, and 10c, through which light from each LED is directed. The three separate light beam paths from the three LEDs 10a, 10b, and 10c are then directed through a series of dichroic mirrors 66a and 66b, where they converge to form a single light beam path. The dichroic mirror 66a transmits the green light from LED 10a and reflects the red light from LED 10b. Similarly, the dichroic mirror 66b transmits the green and red light from LEDs 10a and 10b and reflects the blue light from LED 10c. This converges the red, green, and blue light to form a single light beam path. The light then passes through a microlens array 68, a meniscus lens 70, a first biconvex lens 72a, and a folding prism 74, in that order. The light beam path through the folding prism 74 is directed to a pixel forming device 76. The pixel forming device 76 can be, for example, a liquid crystal on silicon (LCOS) panel, a digital micromirror device (DMD), or other display device. The ray paths then pass back through folding prism 74 to second bi-convex lens 72b and on to a series of projection doublets 78a and 78b. The ray paths then pass to LFP lens 98. The ray paths pass to a multiplexing layer and then to display optics 22. The projected multiplexed light field output 112 from display optics 22 includes two separate light field images, shown as a first set of rays indicated by solid lines and a second set of rays indicated by dashed lines.Together, these constitute the multiplexed light field output 112. Note that in this configuration, the display optics 22 can be any suitable display optical component, including, but not limited to, a single lens, a lens array, a pinhole array, a metasurface, or a metalens. While multiplexing can be achieved using one or more multiplexing devices, as described in other embodiments, multiplexing can also be achieved by modifying the refractive index of an additional multiplexing layer 118. This is achieved because the multiplexing layer 118, which can produce the Kerr effect, is a component made of a material that can adjust the refractive index of the material in response to an applied electric field. Various materials are known that can produce the quadratic electro-optic effect, and the same or similar multiplexed images can be obtained by using a single optical component made of these materials in combination with a device that can generate the electric field necessary to adjust the refractive index of the material. This can be achieved in one and / or two dimensions.

[0138] FIG. 3A illustrates one embodiment of a light field projector configuration with multiplexing. This configuration includes a series of optical systems, with projection optics 14 positioned as shown, and ray paths directed to collimating optics 18. Collimating optics 18 is comprised of a bi-convex lens 72c. Projection optics 14 and collimating optics 18 are housed within the projector body, as shown in FIG. 1. In this configuration, light emitted from green LED 10a, red LED 10b, and blue LED 10c is directed to projection optics 14. The illustrated projection optics 14 includes a series of three plano-convex lenses 80a, 80b, and 80c, one for each of LEDs 10a, 10b, and 10c, through which the light from each LED is directed. The three separate ray paths resulting from the three LEDs 10a, 10b, and 10c are then directed through a series of dichroic mirrors 66a and 66b and combined to form a single ray path. Dichroic mirror 66a transmits the green light from LED 10a and reflects the red light from LED 10b. Similarly, dichroic mirror 66b transmits the green and red light from LEDs 10a and 10b and reflects the blue light from LED 10c. This causes the red, green, and blue light to merge into a single light path. The light then passes through microlens array 68, meniscus lens 70, first biconvex lens 72a, and folding prism 74. The light path through folding prism 74 is directed toward pixel forming device 76, which may be, for example, a liquid crystal on silicon (LCOS) panel, a digital micromirror device (DMD), or other display device. The light path then passes back through folding prism 74 to second biconvex lens 72b and onto a series of projection doublets 78a and 78b. The ray path then proceeds to collimating optics 18, which in this embodiment includes a further bi-convex lens 72c, and on to display optics 22. The projected multiplexed light field output 112 from display optics 22 includes two separate light field images, shown as a first set of rays indicated by solid lines and a second set of rays indicated by dashed lines, which together comprise multiplexed light field output 112.It should be noted that in this configuration, display optics 22 may be any suitable display optics, including, but not limited to, a single lens, a lens array, a pinhole array, a metasurface, or a metalens.

[0139] To generate more pixels in one direction based on the design, multiplexing can be achieved by shifting the bi-convex lens 72c along the second axis 116 or the third axis 122 using a multiplexing actuator programmed to shift the incident pixels by a quarter-integer or half-integer pixel value corresponding to the corresponding frame. Multiplexing can also be achieved by shifting the bi-convex lens 72c along the second axis 116 and the third axis 122 by a quarter-integer or half-integer pixel value in each direction. The end of each movement corresponds to a frame, increasing the effective pixels in both directions. Multiplexing can also be achieved by deforming the bi-convex lens 72c or manipulating the refractive index of the material to provide an effective resolution increase in both directions. Furthermore, moving the bi-convex lens 72c along the first axis 114 toward the positive z-direction can slightly increase the divergence of the pixels in the projected image, increasing the size of the projected image at the imaging plane by an amount equivalent to shifting only a quarter-integer or half-integer pixel value. Similarly, moving the bi-convex lens 72c in the negative z-direction to reduce divergence can produce a smaller projected image at the imaging plane, depending on the spatial constraints of the design. Other multiplexing techniques can also include manipulating the pixel-forming device 76, which may be, for example, a liquid crystal on silicon (LCOS) panel, a digital micromirror device (DMD), or other display device using multiplexing actuators. As shown in FIG. 3A , the pixel-forming device 76 can be shifted along a first axis 114, a second axis 116, or a combination of both axes. Manipulation of the pixel-forming device 76 position is synchronized with the input image so that the device movement enhances resolution in one or two dimensions. Multiplexing can also be achieved by manipulating the fold prism 74 using a multiplexing actuator along the second axis 116, the third axis 122, or both axes in synchronization with the input frame to enhance the effective resolution in one or both directions.

[0140] Projector configurations such as that shown in FIG. 3A can also be multiplexed by manipulating the second bi-convex lens 72b using a multiplexed actuator or other suitable component or multiplexing method. In one embodiment, the second bi-convex lens 72b can be shifted along either the second axis 116, the third axis 122, or any combination of the first, second, and third axes 114, 116, and 122, with each shifted endpoint increasing the effective resolution of the output device by a corresponding number of frames. The second bi-convex lens 72b can also be fabricated using a crystal or other material that changes its refractive index in response to an applied electric field or the Kerr effect, and in conjunction with a device to which a desired voltage can be controllably applied to produce the desired refractive index change. This allows the focus of element 72b to be shifted by a calibrated amount at a frequency corresponding to the input frame rate to increase the effective resolution. A further multiplexing technique, shown in FIG. 3A , involves manipulating the position of the first projection doublet 78 a or the second projection doublet 78 b along a first axis 114. Moving one of the projection doublets 78 a, 78 b or varying the distance between the projection doublets 78 a, 78 b along the first axis 114 changes the focus of the projection system, increasing or decreasing the magnification of the projected image. For example, moving the projection doublet 78 a increases the image size by a quarter-integer or half-integer number of pixels relative to the input frame, creating a multiplexing effect in both dimensions and increasing the effective resolution. Because small movements are required, this can be achieved, for example, by using small piezoelectric transducers.

[0141] FIG. 3B shows one embodiment of a light field projector configuration with multiplexing. This configuration includes a series of optics, with projection optics 14 positioned as shown, and ray paths directed to collimating optics 18. Collimating optics 18 is comprised of a bi-convex lens 72c. Projection optics 14 and collimating optics 18 are housed within the projector body, as shown in FIG. 1. In this configuration, light emitted from green LED 10a, red LED 10b, and blue LED 10c is directed to projection optics 14. The illustrated projection optics 14 includes a series of three plano-convex lenses 80a, 80b, and 80c, one for each of LEDs 10a, 10b, and 10c, through which the light from each LED is directed. The three separate ray paths resulting from the three LEDs 10a, 10b, and 10c are then directed through a series of dichroic mirrors 66a and 66b and combined to form a single ray path. Dichroic mirror 66a transmits the green light from LED 10a and reflects the red light from LED 10b. Similarly, dichroic mirror 66b transmits the green and red light from LEDs 10a and 10b and reflects the blue light from LED 10c. This causes the red, green, and blue light to merge into a single light path. The light then passes through microlens array 68, meniscus lens 70, first biconvex lens 72a, and folding prism 74. The light path through folding prism 74 is directed toward pixel forming device 76, which may be, for example, a liquid crystal on silicon (LCOS) panel, a digital micromirror device (DMD), or other display device. The light path then passes back through folding prism 74 to second biconvex lens 72b and onto a series of projection doublets 78a and 78b. The ray path then proceeds to collimating optics 18, which in this embodiment includes a further bi-convex lens 72c, and on to display optics 22. The projected multiplexed light field output 112 from display optics 22 includes two separate light field images, shown as a first set of rays indicated by solid lines and a second set of rays indicated by dashed lines, which together comprise multiplexed light field output 112.Note that in this configuration, the display optics 22 may be any suitable display optics, including, but not limited to, a single lens, a lens array, a pinhole array, a metasurface, or a metalens. In this embodiment, the multiplexing device 124 is a multiplexing actuator in-line with the folded prism 74 and the pixel-forming device 76. This allows the multiplexing device 124 to shift both components in one, two, or three dimensions, in the x, y, or z directions, or any combination thereof. The multiplexing device 124 may be, but is not limited to, a piezoelectric actuator, an electrothermal actuator, a magnetic actuator, an electrostatic actuator, or a shape-memory-alloy-based actuator.

[0142] FIG. 3C shows one embodiment of a light field projector configuration with multiplexing. This configuration includes a series of optics, with projection optics 14 positioned as shown, and ray paths directed to collimating optics 18. Collimating optics 18 is comprised of a bi-convex lens 72c. Projection optics 14 and collimating optics 18 are housed within the projector body, as shown in FIG. 1. In this configuration, light emitted from green LED 10a, red LED 10b, and blue LED 10c is directed to projection optics 14. The illustrated projection optics 14 includes a series of three plano-convex lenses 80a, 80b, and 80c, one for each of LEDs 10a, 10b, and 10c, through which the light from each LED is directed. The three separate ray paths resulting from the three LEDs 10a, 10b, and 10c are then directed through a series of dichroic mirrors 66a and 66b and combined to form a single ray path. Dichroic mirror 66a transmits the green light from LED 10a and reflects the red light from LED 10b. Similarly, dichroic mirror 66b transmits the green and red light from LEDs 10a and 10b and reflects the blue light from LED 10c. This causes the red, green, and blue light to merge into a single light path. The light then passes through microlens array 68, meniscus lens 70, first biconvex lens 72a, and folding prism 74. The light path through folding prism 74 is directed toward pixel forming device 76, which may be, for example, a liquid crystal on silicon (LCOS) panel, a digital micromirror device (DMD), or other display device. The light path then passes back through folding prism 74 to second biconvex lens 72b and onto a series of projection doublets 78a and 78b. The ray path then proceeds to collimating optics 18, which in this embodiment includes a further bi-convex lens 72c, and on to display optics 22. The projected multiplexed light field output 112 from display optics 22 includes two separate light field images, shown as a first set of rays indicated by solid lines and a second set of rays indicated by dashed lines, which together comprise multiplexed light field output 112.Note that in this configuration, display optics 22 may be any suitable display optics, including, but not limited to, a single lens, a lens array, a pinhole array, a metasurface, or a metalens. In this embodiment, multiplexing device 124 is a multiplexing actuator positioned adjacent to folded prism 74 and pixel forming device 76. Shifting these components in the x, y, or z direction, or any combination thereof, by a desired amount to achieve multiplexed light field output 112 increases the effective resolution of the projection system.

[0143] FIG. 3D shows one embodiment of a light field projector configuration with multiplexing. This configuration includes a series of optical systems, with projection optics 14 positioned as shown, and light ray paths directed to collimating optics 18. Collimating optics 18 is comprised of bi-convex lens 72c. Also in FIG. 3D, a multiplexing layer 118 is positioned immediately before display optics 22. Projection optics 14 and collimating optics 18 are housed within the projector body, as shown in FIG. 1. Also in FIG. 3D, a multiplexing layer 118 is positioned immediately before display optics 22. In this configuration, light emitted from green LED 10a, red LED 10b, and blue LED 10c is directed toward projection optics 14. The illustrated projection optics 14 includes a series of three plano-convex lenses 80a, 80b, and 80c, one for each of LEDs 10a, 10b, and 10c, through which light from each LED is directed. The three separate light beam paths from the three LEDs 10a, 10b, and 10c are then directed through a series of dichroic mirrors 66a and 66b, where they converge to form a single light beam path. The dichroic mirror 66a transmits the green light from LED 10a and reflects the red light from LED 10b. Similarly, the dichroic mirror 66b transmits the green and red light from LEDs 10a and 10b and reflects the blue light from LED 10c. This converges the red, green, and blue light to form a single light beam path. The light then passes through a microlens array 68, a meniscus lens 70, a first biconvex lens 72a, and a folding prism 74, in that order. The light beam path through the folding prism 74 is directed to a pixel forming device 76. The pixel forming device 76 can be, for example, a liquid crystal on silicon (LCOS) panel, a digital micromirror device (DMD), or other display device. The ray path then passes back through folding prism 74 to the second bi-convex lens 72b and on to a series of projection doublets 78a and 78b. The ray path then passes to collimating optics 18, which in this embodiment includes a further bi-convex lens 72c.The multiplexed light field output 112 projected from the display optics 22 includes two separate light field images, shown as a first set of solid rays and a second set of dashed rays, which together comprise the multiplexed light field output 112. In this configuration, the display optics 22 can be any suitable display optical component, including, but not limited to, a single lens, a lens array, a pinhole array, a metasurface, or a metalens. In this configuration, multiplexing can be achieved by modifying the refractive index of an additional multiplexing layer 118. The multiplexing layer 118, which serves as the multiplexer in this configuration, can take the form of, for example, an optical modulator with gate-tunable response characteristics, a metamaterial with self-assembled nanopatterns with tunable period and symmetry, or a multi-nanolayer tunable material. In this example, light path redirection can be achieved in one or two dimensions.

[0144] FIG. 4A shows another configuration of the projection optical system 14 and collimation optical system 18, as shown in FIG. 1, housed within the projector body. In this configuration, light emitted from a light source within an LED package 100 is directed toward the projection optical system 14. The LED package 100 can be composed of one or more LEDs that generate multiple light beams directed toward the projection optical system 14. When the LED package 100 has multiple LEDs, the LEDs are preferably arranged in an array or dense configuration so that the light emitted from the LED package 100 is highly focused and has a small diameter. The LED package 100 can also include LEDs of one or more colors, depending on the system design. Preferably, the LED package 100 includes at least three LEDs, including green, red, and blue LEDs. The projection optical system 14 is comprised of an illumination optical system that receives light from the LED package 100. First, the light from the LED package 100 is received by a plano-convex lens 80. The ray path is then directed to a first bi-convex lens 72a, followed by a pair of meniscus lenses 70a, 70b, and then to a single prism 82. The ray path through prism 82 is then directed to a folding prism 74 and a pixel forming device 76, preferably a digital micromirror device (DMD), and then back through the folding prism 74. The ray path proceeds through a second bi-convex lens 72b followed by a magnifying optics having a series of projection doublets 78a, 78b. The ray path then proceeds to collimating optics 18, which in this embodiment is an LFP lens 98. The LFP lens 98 serves to collimate the incident light. The ray path continues to display optics 22. The projected multiplexed light field output 112 from display optics 22 includes two separate light field images, shown as a first set of rays indicated by solid lines and a second set of rays indicated by dashed lines. Together, these comprise the multiplexed light field output 112. In this configuration, the display optics 22 can be any suitable display optics, including, but not limited to, a single lens, a lens array, a pinhole array, a metasurface, or a metalens.Depending on the design, multiplexing can be achieved using a multiplexing device by shifting the LFP lens 98 along the second axis 116 or the third axis 122 using a multiplexing actuator programmed to shift the incident pixels by a quarter-integer or half-integer pixel value corresponding to the corresponding frame to generate more pixels in one direction. Multiplexing can also be achieved by shifting the LFP lens 98 along the second axis 116 and the third axis 122 by a quarter-integer or half-integer pixel value in each direction, with the end of each movement corresponding to a frame, increasing the effective pixels in both directions. Multiplexing can also be achieved by deforming the LFP lens 98 or manipulating the refractive index of the material, effectively improving resolution in both directions. Moving the LFP lens 98 along the first axis 114 toward the positive z-direction can slightly increase the divergence of the pixels in the projected image, increasing the size of the projected image at the imaging plane by an amount equivalent to shifting the pixel values ​​by a quarter-integer or half-integer. Similarly, the LFP lens 98 can be moved in the negative z direction to reduce divergence, producing a smaller projected image at the imaging plane, depending on the space constraints of the design.

[0145] Multiplexing techniques can also include manipulating the pixel-forming device 76, which may be, for example, a liquid crystal on silicon (LCOS) panel, a digital micromirror device (DMD), or other display device using a multiplexing actuator or other suitable component or method. As shown in FIG. 4A, the pixel-forming device 76 can be shifted along a first axis 114, a second axis 116, or a combination of both axes. Manipulation of the pixel-forming device 76 position is synchronized with the input image so that the device movement enhances resolution in one or two dimensions. Multiplexing can also be achieved by manipulating the folded prism 74 using a multiplexing actuator along the second axis 116, the third axis 122, or both axes in synchronization with the input frame to enhance the effective resolution in one or both directions. A projector configuration such as that shown in FIG. 4A can be multiplexed by manipulating the second bi-convex lens 72b using a multiplexing actuator or other suitable component or multiplexing method. The second biconvex lens 72b can be shifted along the second axis 116, the third axis 122, or any combination thereof, with each shifted endpoint increasing the effective resolution of the output device by a corresponding number of frames. An equivalent embodiment includes fabricating element 72b with a crystalline material that changes its refractive index in response to an applied electric field or the Kerr effect. This allows the focus of element 72b to be shifted by a calibrated amount at a frequency corresponding to the input frame rate to increase the effective resolution. A further multiplexing technique, shown in FIG. 4A , involves manipulating the position of either the first projection doublet 78a or the second projection doublet 78b along the first axis 114. Moving one of the projection doublets changes the focus of the projection system, increasing or decreasing the magnification of the projected image. For example, if moving element 78a increases the image size by a quarter-integer or half-integer number of pixels relative to the input frame, a multiplexing effect occurs in both dimensions, increasing the effective resolution. Since small movements are required, this can be achieved by using small piezoelectric transducers.

[0146] FIG. 4B shows another configuration of the projection optical system 14 and collimation optical system 18, as shown in FIG. 1, housed within the projector body. In this configuration, light emitted from a light source within an LED package 100 is directed toward the projection optical system 14. The LED package 100 can be composed of one or more LEDs that generate multiple light beams directed toward the projection optical system 14. When the LED package 100 has multiple LEDs, the LEDs are preferably arranged in an array or dense configuration so that the light emitted from the LED package 100 is highly focused and has a small diameter. The LED package 100 can also include LEDs of one or more colors, depending on the system design. Preferably, the LED package 100 includes at least three LEDs, including green, red, and blue LEDs. The projection optical system 14 is comprised of an illumination optical system that receives light from the LED package 100. First, the light from the LED package 100 is received by a plano-convex lens 80. The ray path is then directed to a first bi-convex lens 72a, followed by a pair of meniscus lenses 70a, 70b, and then to a single prism 82. The ray path through prism 82 is then directed to a folding prism 74 and a pixel forming device 76, preferably a digital micromirror device (DMD), and then back through the folding prism 74. The ray path proceeds through a second bi-convex lens 72b followed by a magnifying optics having a series of projection doublets 78a, 78b. The ray path then proceeds to collimating optics 18, which in this embodiment is an LFP lens 98. The LFP lens 98 serves to collimate the incident light. The ray path continues to display optics 22. The projected multiplexed light field output 112 from display optics 22 includes two separate light field images, shown as a first set of rays indicated by solid lines and a second set of rays indicated by dashed lines. Together these comprise the multiplexed light field output 112.Note that in this configuration, display optics 22 may be any suitable display optics, including, but not limited to, a single lens, a lens array, a pinhole array, a metasurface, or a metalens. In this embodiment, multiplexer 124 is aligned with single prism 82, folded prism 74, and pixel-forming device 76. This allows multiplexer 124 to shift both components in 1D or 2D in the x, y, z directions, or any combination thereof. Multiplexer 124 may be, but is not limited to, a piezoelectric actuator, an electrothermal actuator, a magnetic actuator, an electrostatic actuator, or a shape-memory-alloy-based actuator.

[0147] FIG. 4C shows another configuration of the projection optical system 14 and collimation optical system 18, as shown in FIG. 1, housed within the projector body. In this configuration, light emitted from a light source within an LED package 100 is directed toward the projection optical system 14. The LED package 100 can be composed of one or more LEDs that generate multiple light beams directed toward the projection optical system 14. When the LED package 100 has multiple LEDs, the LEDs are preferably arranged in an array or dense configuration so that the light emitted from the LED package 100 is highly focused and has a small diameter. The LED package 100 can also include LEDs of one or more colors, depending on the system design. Preferably, the LED package 100 includes at least three LEDs, including green, red, and blue LEDs. The projection optical system 14 is comprised of an illumination optical system that receives light from the LED package 100. First, the light from the LED package 100 is received by a plano-convex lens 80. The ray path is then directed to a first bi-convex lens 72a, followed by a pair of meniscus lenses 70a, 70b, and then to a single prism 82. The ray path through prism 82 is then directed to a folding prism 74 and a pixel forming device 76, preferably a digital micromirror device (DMD), and then back through folding prism 74. The ray path proceeds through a second bi-convex lens 72b followed by magnifying optics having a series of projection doublets 78a, 78b. The ray path then proceeds to collimating optics 18, which in this embodiment is an LFP lens 98. The ray path continues to display optics 22. The projected multiplexed light field output 112 from display optics 22 includes two separate light field images, shown as a first set of rays indicated by solid lines and a second set of rays indicated by dashed lines, which together comprise multiplexed light field output 112. In this configuration, display optics 22 can be any suitable display optics, including, but not limited to, a single lens, a lens array, a pinhole array, a metasurface, or a metalens.In this embodiment, the multiplexer 124 is connected to the single prism 82, the folding prism 74, and the pixel forming device 76, and shifts these components by a desired amount to produce the multiplexed light field output 112 and increase the effective resolution of the projection device.

[0148] FIG. 4D shows another configuration of the projection optics 14 and collimation optics 18 housed within the projector body, as shown in FIG. 1 . FIG. 4D also includes a multiplexing layer 118 located immediately prior to the display optics 22. In this configuration, light emitted from a light source within the LED package 100 is directed toward the projection optics 14. The LED package 100 can be composed of one or more LEDs that generate multiple light beams directed into the projection optics 14. When the LED package 100 has multiple LEDs, the LEDs are preferably arranged in an array or dense configuration so that the light emitted from the LED package 100 is highly focused and has a small diameter. The LED package 100 can also include LEDs of one or more colors, depending on the system design. Preferably, the LED package 100 includes at least three LEDs, including one each of green, red, and blue. The projection optics 14 is comprised of an illumination optics system that receives light from the LED package 100. First, light from the LED package 100 is received by a plano-convex lens 80. The ray path is then directed to a first bi-convex lens 72a, followed by a pair of meniscus lenses 70a, 70b, and then to a single prism 82. The ray path through prism 82 is then directed to a folding prism 74 and a pixel forming device 76, preferably a digital micromirror device (DMD), and then back through the folding prism 74. The ray path proceeds through a second bi-convex lens 72b, followed by magnifying optics having a series of projection doublets 78a, 78b. The ray path then proceeds to collimating optics 18, which in this embodiment is an LFP lens 98. The ray path continues to display optics 22. The projected multiplexed light field output 112 from display optics 22 includes two separate light field images, shown as a first set of rays indicated by solid lines and a second set of rays indicated by dashed lines. Together these comprise the multiplexed light field output 112.In this configuration, the display optics 22 can be any suitable display optics, including, but not limited to, a single lens, a lens array, a pinhole array, a metasurface, or a metalens. In this configuration, multiplexing can be achieved by modifying the refractive index of the further multiplexing layer 118. This can be achieved, for example, in one or two dimensions.

[0149] FIG. 5A shows another configuration of the projection optics 14 and collimation optics 18, housed within the projector body as shown in FIG. 1. In this configuration, light emitted from a light-emitting diode (LED) 10 or a light-emitting diode (LED) package 100 is directed toward the projection optics 14. The LED package 100 can be composed of one or more LEDs that generate multiple light beams directed into the projection optics 14. When the LED package 100 has multiple LEDs, the LEDs are preferably arranged in an array or dense configuration so that the light emitted from the LED package 100 is highly focused and small in diameter. The LED package 100 can also include LEDs of one or more colors, depending on the system design. Preferably, the LED package 100 includes at least two LEDs. Light from the LED 10 is directed through its own plano-convex lens 80a, and light from the LED package 100 is directed toward a plano-convex lens 80b. The two separate light beam paths are then directed to the illumination optics, starting with a dichroic mirror 66a, which combines the light to form a single light beam path. The LED 10 can be a single color that is transmitted by the dichroic mirror 66a, while the LED package 100 can have any other color that is reflected by the dichroic mirror 66a to form a single light beam path. For example, if the LED package 100 emits blue and red light and the LED 10 is a green LED, the dichroic mirror 66a will transmit the green light from the LED 10 and reflect the red and blue light from the LED package 100. The light beam path in the illumination optics continues through a microlens array 68, a meniscus lens 70, and a dichroic mirror 66b. The dichroic mirror 66b reflects the green, red, and blue light from the LED 10 and the LED package 100. The light is redirected through a biconvex lens 72 and a single prism 82. The ray path through prism 82 is directed to pixel forming device 76, then back through single prism 82 and on to a series of projection doublets 78. The light is redirected through bi-convex lens 72 and through single prism 82.The ray path through prism 82 is directed to pixel formation device 76, then returns through single prism 82 and passes through magnification optics, including a series of projection doublets 78a, 78b. The ray path then proceeds to collimating optics 18, which in this embodiment is LFP lens 98. The function of LFP lens 98 in collimating optics 18 is to collimate the light from projection optics 14. The ray path continues to display optics 22. The multiplexed light field output 112 projected from display optics 22 includes two separate light field images, shown as a first set of rays indicated by solid lines and a second set of rays indicated by dashed lines, which together comprise multiplexed light field output 112. Note that in this configuration, display optics 22 may be any suitable display optics, including, but not limited to, a single lens, a lens array, a pinhole array, a metasurface, or a metalens. Depending on the design, multiplexing can be achieved using a multiplexer by shifting the LFP lens 98 along the second axis 116 or the third axis 122 using a multiplexing actuator programmed to shift the incident pixels by a quarter-integer or half-integer pixel value corresponding to the corresponding frame to generate more pixels in one direction. Multiplexing can also be achieved using a multiplexer by shifting the LFP lens 98 by a quarter-integer or half-integer pixel value in each direction along the second axis 116 and the third axis 122. The end of each movement corresponds to a frame, increasing the effective pixels in both directions. Multiplexing can also be achieved using a multiplexer to effect deformation of the LFP lens 98 or by manipulating the refractive index of the material to provide effective resolution enhancement in both directions. In some cases, the LFP lens is made from a deformable material, and the multiplexer applies a controllable deformation force to the LFP lens to effect the deformation. In another case, the change in refractive index of the LFP lens can be achieved by the LFP lens being made of a material or composition that allows the refractive index to be changed, and the multiplexing device includes an electrical device that causes the change in refractive index in the LFP lens.Additionally, LFP lens 98 can be moved along first axis 114 toward the positive z direction to slightly increase the divergence of the pixels in the projected image, increasing the size of the projected image at the imaging plane by an amount equivalent to shifting the pixel values ​​by a quarter-integer or half-integer number. Similarly, LFP lens 98 can be moved in the negative z direction to decrease the divergence, producing a smaller projected image at the imaging plane, depending on the spatial constraints of the design.

[0150] Multiplexing techniques can also include manipulating pixel-forming devices 76, which may be, for example, liquid crystal on silicon (LCOS) panels, digital micromirror devices (DMDs), or other display devices using multiplexing actuators or other suitable components or techniques. As shown in FIG. 5A, pixel-forming devices 76 can be shifted along a first axis 114, a second axis 116, or a combination of both axes. Manipulation of the position of pixel-forming devices 76 is synchronized with the input image so that device movement enhances resolution in one or two dimensions. Multiplexing can also be achieved by manipulating a single prism 82 using a multiplexing actuator along a second axis 116, a third axis 122, or both axes in synchronization with the input frame to enhance the effective resolution in one or both directions. A further multiplexing technique, shown in FIG. 5A, is one in which the position of a first projection doublet 78a or a second projection doublet 78b is manipulated along a first axis 114. Moving one of the projection doublets changes the focus of the projection system, increasing or decreasing the magnification of the projected image. For example, if moving element 78a increases the image size by a quarter-integer or half-integer number of pixels relative to the input frame, a multiplexing effect occurs in both dimensions, increasing the effective resolution. Because small movements are required, this can be achieved using small piezoelectric transducers.

[0151] FIG. 5B shows a configuration of the projection optical system 14 and collimation optical system 18 integrated into the projector body, as shown in FIG. 1. In this configuration, light emitted from a light-emitting diode (LED) 10 or a light-emitting diode (LED) package 100 is directed toward the projection optical system 14. The LED package 100 can be composed of one or more LEDs that generate multiple light beams directed into the projection optical system 14. When the LED package 100 has multiple LEDs, the LEDs are preferably arranged in an array or dense configuration so that the light emitted from the LED package 100 is fairly focused and small in diameter. The LED package 100 can also include LEDs of one or more colors, depending on the system design. Preferably, the LED package 100 includes at least two LEDs. Light from the LED 10 is directed through its own plano-convex lens 80a, and light from the LED package 100 is directed toward a plano-convex lens 80b. The two separate light beam paths are then directed to the illumination optics, starting with a dichroic mirror 66a, which combines the light to form a single light beam path. The LED 10 can be a single color that is transmitted by the dichroic mirror 66a, while the LED package 100 can have any other color that is reflected by the dichroic mirror 66a to form a single light beam path. For example, if the LED package 100 emits blue and red light and the LED 10 is a green LED, the dichroic mirror 66a will transmit the green light from the LED 10 and reflect the red and blue light from the LED package 100. The light beam path in the illumination optics continues through a microlens array 68, a meniscus lens 70, and a dichroic mirror 66b. The dichroic mirror 66b reflects the green, red, and blue light from the LED 10 and the LED package 100. The light is redirected through a biconvex lens 72 and a single prism 82. The ray path through prism 82 is directed to pixel forming device 76, then back through single prism 82 and on to a series of projection doublets 78. The light is redirected through bi-convex lens 72 and through single prism 82.The ray path through prism 82 is directed to pixel formation device 76, then returns through single prism 82 and passes through magnification optics, including a series of projection doublets 78a, 78b. The ray path then proceeds to collimating optics 18, which in this embodiment is LFP lens 98. The function of LFP lens 98 in collimating optics 18 is to collimate the light from projection optics 14. The ray path continues to display optics 22. The multiplexed light field output 112 projected from display optics 22 includes two separate light field images, shown as a first set of rays indicated by solid lines and a second set of rays indicated by dashed lines, which together comprise multiplexed light field output 112. Note that in this configuration, display optics 22 can be any suitable display optic, including but not limited to a single lens, a lens array, a pinhole array, a metasurface, or a metalens, which serves to direct pixels to different viewing regions to provide a 3D display. In this embodiment, the multiplexer 124 is aligned with the single prism 82 and the pixel forming device 76. This allows both components to be shifted in 1D or 2D by the multiplexer 124, which can be, but is not limited to, a piezoelectric actuator, an electrothermal actuator, a magnetic actuator, an electrostatic actuator, or a shape memory alloy based actuator.

[0152] FIG. 5C shows a configuration of the projection optics 14 and collimation optics 18 integrated into the projector body, as shown in FIG. 1. FIG. 5C also includes a multiplexing layer 118 located immediately before the display optics 22. In this configuration, light emitted from a light-emitting diode (LED) 10 or a light-emitting diode (LED) package 100 is directed toward the projection optics 14. The LED package 100 can be composed of one or more LEDs that generate multiple light beams directed into the projection optics 14. When the LED package 100 has multiple LEDs, the LEDs are preferably arranged in an array or dense configuration so that the light emitted from the LED package 100 is fairly focused and has a small diameter. The LED package 100 can also include LEDs of one or more colors, depending on the system design. Preferably, the LED package 100 includes at least two LEDs. Light from the LED 10 is directed through its own plano-convex lens 80a, and light from the LED package 100 is directed toward a plano-convex lens 80b. The two separate light beam paths are then directed to the illumination optics, starting with a dichroic mirror 66a, which combines the light to form a single light beam path. The LED 10 can be a single color that is transmitted by the dichroic mirror 66a, while the LED package 100 can have any other color that is reflected by the dichroic mirror 66a to form a single light beam path. For example, if the LED package 100 emits blue and red light and the LED 10 is a green LED, the dichroic mirror 66a will transmit the green light from the LED 10 and reflect the red and blue light from the LED package 100. The light beam path in the illumination optics continues through a microlens array 68, a meniscus lens 70, and a dichroic mirror 66b. The dichroic mirror 66b reflects the green, red, and blue light from the LED 10 and the LED package 100. The light is redirected through a biconvex lens 72 and a single prism 82. The ray path through prism 82 is directed to pixel forming device 76 and then back through a single prism 82 to a series of projection doublets 78 .The light passes through the bi-convex lens 72 and is redirected through a single prism 82. The ray path through prism 82 is directed to the pixel forming device 76, then returns through the single prism 82 and passes through magnification optics, including a series of projection doublets 78 a, 78 b. The ray path then proceeds to the collimating optics 18, which in this embodiment is an LFP lens 98. The function of the LFP lens 98 in the collimating optics 18 is to collimate the light from the projection optics 14. The ray path continues to the display optics 22.

[0153] Figures 2A-2I, 3A-3D, 4A-4D, and 5A-5C illustrate various apparatus and methods for multiplexing an embodiment of a light field projector according to the present disclosure. It is understood that light field projectors and any projector variations suitable for creating a light field display can be multiplexed using the methods described above.

[0154] FIG. 6A is a front view of a collimating lens array 26, which serves as a collimating lens array in a collimating optical system. In this example, the collimating lens array 26 is generally rectangular and includes a plurality of collimating lenslets 32, also referred to as lenslets, a close-up of which is shown in FIG. 6D. Collimating lens array 26 can be constructed using a substrate to which a plurality of lenslets or collimating lenslets 32 are bonded to form a single component fixed to the substrate. For example, this bonding can be achieved using an optically transparent adhesive with a specific refractive index or optically transparent tape. For example, the substrate can be made of cyclic olefin copolymer (COC), glass, cyclic olefin polymer (COP), PMMA, polycarbonate, polystyrene, isoplast, Zeonex® E48R, optical polyester, acrylic, polyetherimide (PEI), or other suitable materials. The collimating lens array 26 includes one or more collimating lenslets 32 arranged in alignment with a corresponding LED upstream of the projection optics, such that each collimating lenslet 32 ​​receives light from the LED. One or both sides of the collimating lens array 26 can be coated with an anti-reflective coating. In the example of FIG. 6B , the collimating lenslets 32 include two plano-convex lenses and a substrate. The convex lenses can be formed of, for example, Zeonex® E48R, glass, cyclic olefin polymer (COP), PMMA, polystyrene, isoplast, optical polyester, acrylic, polyetherimide (PEI), or other suitable materials. The two plano-convex lenses and the substrate can be arranged to form a single aspheric bi-convex lens that can act as the collimating lenslet 32.

[0155] FIG. 6B is an enlarged view of a 2×4 grid of collimating lens arrays with collimating lenslets 32 shown in FIG. 6A.

[0156] FIG. 6C is a profile diagram of the collimating lens array shown in FIG. 6A with a laser-etched optical diffuser 34. Optical diffusers are advanced optical beam shapers that can homogenize an input beam and shape the output intensity profile and the path the light is spatially dispersed. Optical diffusers can produce a non-Gaussian intensity distribution in a circular or square beam profile diverging from the input surface. Optical diffusers can be, for example, polymer-on-glass, such as replicated polymer on a glass substrate; etched hard materials such as plastic-embossed fused silica, silicon, or germanium; injection-molded plastic parts; or micro-optical elements on a flexible substrate. Some specific examples of optical diffusers are laser-etched diffusers and optical holographic diffusers.

[0157] FIG. 6D is an enlarged isometric view of a single collimating lenslet 32 ​​in the collimating lens array shown in FIG. 6A.

[0158] 7A is a diagram of a diffuser 36, which may optionally be present in a projector downstream of the collimating optics along the light path. In this embodiment, the diffuser 36 is a laser-etched diffuser that serves to scatter the light rays. In some embodiments, the diffuser 36 is a single diffuser lenslet or a diffuser lenslet array as shown in FIG. 7C. In one embodiment of the present disclosure, the diffuser 36 has a circular angle of 3.5 degrees and does not require a coating.

[0159] Figure 7B is a close-up view of the laser-etched engineered diffuser 34, enlarged as section A in Figure 7A, which shows the molecular arrangement of the laser-etched engineered diffuser.

[0160] 7C is a close-up view of one embodiment of a laser-etched engineered diffuser, diffuser lenslet array 38. Diffuser lenslet array 38 is another diffusing component that is composed of multiple diffusing lenslets, as opposed to a laser-etched engineered diffusing surface.

[0161] 8A shows display optics 22, shown as a single display lens. The display lens is made up of an array of hogels and serves to redirect collimated light rays from the collimating optics into a distribution of light rays over the angular range represented by the field of view of the display, such that the collection of collimated light rays forms a light field image.

[0162] FIG. 8B illustrates additional display optics as a metasurface, metalens, or metamaterial. The display lens can be, for example, a periodic array of lenses, a metasurface, a metalens, or any type of optical waveguide. Optical metasurfaces are engineered surfaces used to manipulate the polarization, phase, and amplitude of light. Optical metasurfaces generally consist of a two-dimensional lattice of pillar-type structures that interact with an impinging wavefront. The lattice constant and structure size are subwavelength thick for the electromagnetic wavelength range the structure is designed to interact with. The pillar dimensions and spacing in the metasurface can be engineered to achieve desired optical properties. The use of metasurfaces in light field display technology can result in substantially flat optical devices, improve the performance of optical elements, and manipulate light to create new properties in optical systems.

[0163] FIG. 8C shows a further alternative display optics as an optical surface that serves to redirect collimated light rays from collimating optics 18 into a distribution of light rays over the angular range represented by the field of view of the display, so that the collection of collimated light rays forms a light field image.

[0164] FIG. 9 shows the ray path of light emitted from an LED 10 or LED package in a light field projector. As shown, light rays 12 are emitted from a light source, preferably a light-emitting diode (LED) 10, which may be multiple LEDs in an LED package, through a projection optical system 14. The projection optical system 14 can include various optical projector components, as previously described. Light then exits the projection optical system 14 and travels to a collimating optical system 18 to form a first projected image 16, which collimates and diffuses the light rays forming a second projected image 20. The pixel pitch is the spacing between adjacent pixels in the second projected image 20. The pixel pitch increases after the image leaves the pixel-forming device due to the magnification effect of the magnifying optical components. The focal length is the distance between the collimating optical system 18 and the display optical system 22. The collimating optical system 18 collimates the light and can include, for example, a collimating array, one or more lens structures, or optical components capable of collimation. The second projected image 20 then proceeds to display optics 22, which in this case is a display lens. The display lens can be formed of any suitable display optical component, such as a lenslet, metasurface, or array of metalenses, and converts the spatial pixels into a directional view. The output from the display lens in display optics 22 forms a light field image 24. Hogels convert the spatial locations of the pixels into directional light rays, or well-controlled directional light rays. One example of a hogel implementation is provided by a lens onto which a series of pixels are incident. The light field image 24 includes an array of hogels.

[0165] Light field projectors can also include adjustment mechanisms to adjust the direction of the projected image or the light ray path. The adjustments can compensate for errors due to mechanical tolerances, optical aberrations, or other errors that cause the light ray path to deviate from its nominal value. In one embodiment, the adjustment mechanism can be a kinematic adjustment mechanism to enable fine adjustment of the projector in all six degrees of freedom within design tolerances. Specifically, the projector body can be adjusted in all Cartesian directions (x, y, z) and angular directions (yaw, pitch, and roll). Light field projectors can also include digital adjustment mechanisms. Digital adjustment mechanisms can set specific degrees of freedom with physical tolerances and use additional pixels around the display device for device alignment. Both kinematic and digital adjustment mechanisms can also be used in combination. Other features that may be part of the internal optical components may include, but are not limited to, one or more of a static iris, an optical diffuser, and a collimation lens or device, an optical lens, a diffraction grating, a fiber optic, or a laser optic, one or more of which may be incorporated into the light field projector design. The collimation lens may be, for example, a frameless collimation lens design that can utilize a biconvex design of optical components to fill the lens opening in front of the body of the light field projector. The lens opening may be defined as a hole or opening required for light to pass through. The light field projector may also include one or more conventional projector components, such as a printed circuit board (PCB), one or more memories, and a housing. The projector may also include one or more additional internal optical components for further manipulation, diffusion, and / or collimation of the light.One such internal optical component can be, but is not limited to, a piezoelectric actuator, an electrothermal actuator, a magnetic actuator, an electrostatic actuator, or a shape memory alloy-based actuator, which can act as a multiplexing device.

[0166] FIG. 10 shows the ray path of a single pixel in a light field projector. Light rays 12 are emitted from a light-emitting diode (LED) 10 through a projection optics 14. The projection optics 14 can include various arrangements of optical projector components. The projection optics 14 emits light rays to form a first projected image 16 that travels to a collimating optics 18. The collimating optics 18 collimates and diffuses the light rays to form a second projected image 20. The collimating optics includes a collimating lens array 26 that collimates the light and a diffuser 36 that diffuses the light. The second projected image 20 travels to a display optics 22, which is a display lens. The output of the display lens forms a light field image 24. The collimating lens array 26 can include one or more lenses, lenslets, optical mirrors, or collimating optics. The collimating lens array 26 reduces the divergence of the light emitted from the projection optics 14. Collimating lens array 26 is located a throw distance away from projection optics 14. In one embodiment, this throw distance is such that the size of each pixel in the projected image increases proportionally to its neighboring pixels and there is no pixel overlap. Projection optics 14 is positioned such that the distance between projection optics 14 and collimating lens array 26 produces a projected image the same size as a single lenslet in collimating lens array 26.

[0167] The collimated light 30 exiting the collimating lens array 26 travels to a diffuser 36. In some embodiments, the diffuser 36 may include an optical diffuser array or one or more lenses, optical mirrors, or optical materials suitable for diffusion. The diffuser 36 is located between the collimating lens array 26 and the display optics 22, and the diffuser 36 receives the light from the collimating lens array 26. The collimating lens array 26 and the diffuser 36 may be a single, integral component or separate components. The display optics 22 may be positioned to receive the second projected image 20 from the diffuser 36. Thus, the light from the collimating lens array 26 travels to the diffuser 36, which in one embodiment is an optical diffuser array. The output light from the projection optics 14, which forms the first projected image 16, is collimated to maintain the projected size of the image. In the diffuser 36, the divergence of each pixel increases by a factor of: √(C 2 f m 2 ) where C is a constant chosen to properly reconstruct the sampled wavefront, and f m is the fill factor. In one embodiment, the value of C is approximately 2. In such a case, the fill factor f m is approximately 0.9, and the spot size x s is the pixel spacing x p is related to the following equation: x s =x p ·√(C 2 f m 2 ) where x p is the lens pitch divided by the number of angular samples.

[0168] Thus, the diffuser 36 imparts a point spread function to each pixel in the image. The pixels with their point spread functions from the diffuser 36 then enter the back surface of the display optics 22, which constitutes the display lens. As light enters and passes through the diffuser 36, it is dispersed according to the point spread function, which is approximated as a Gaussian function. The diffuser 36 can include an angular diffuser or an optical diffuser array used to achieve the desired diffusion function and prevent bleed-through of light from adjacent pixels. In one embodiment, the projection optics 14 produces an image sized 20 mm x 10 mm at a distance defined by the projector's throw ratio, which is the ratio of the lens-to-screen (projection) distance to the screen width. This image can then be projected onto the collimating lens array 26, resulting in a packet image of the correct size (20 mm x 10 mm) projected toward the diffuser 36, which can be, for example, a diffuser screen or optical diffuser array. The diffuser 36 can then generate a small, defined point spread function. Using the desired point spread function, proper overlap between pixels is achieved to reduce resolution bias error, or the picket fence effect, and distribute light for a better viewing experience. Resolution bias error is the missing information between samples in the spectrum. Reducing the resolution bias error allows for smooth transitions between viewing regions. The diffuser 36 in this case is designed with a very specific angular output, so that, for example, if the designed divergence is 5 degrees annular FWHM, the beam passing through the optical system also has a 5-degree intensity profile. This output is light directed to the display lens of the display optics 22. The display lens can be a metasurface, a metalens, a refractive index-dispersed lens material, or any other suitable display optical component for distributing light from each pixel according to a plenoptic sampling function, as described above.Multiplexing can be achieved by shifting the display optics 22 along the first axis 114, or the second axis 116, or any combination thereof, using some form of multiplexing actuator or custom device to shift the optics a known distance corresponding to an input frame to the display. Multiplexing can also be achieved by deforming the display optics 22. Other display-based multiplexing techniques include manipulating the refractive index of the material of the display optics 22 or adjusting the aperture of the display optics 22 in a pinhole array.

[0169] In a multi-device or multi-projector configuration, each projection optic 14 can be aligned so that light exiting the collimating optic 18 strikes the display optic 22 perpendicularly. Thus, each projection optic 14 can be equipped with alignment hardware and fine adjustment mechanisms for directing light within the projector. Depending on the required tolerances, there are several approaches to aligning the projector or projection optic 14. In one embodiment, one or more adjustment elements, such as a mechanical mount with screw adjusters, can be provided for coarse alignment at a time. In another embodiment, one or more piezoelectric transducers can be provided for electronic adjustment at the nano- to micro-scale, for example. In some cases, these may also be useful for feedback-based active calibration techniques. Other adjustment elements can include kinematic mounts and / or digitally controlled adjustment elements, such as the piezoelectric transducers described above. The maximum amount of adjustment required is determined by the size of the lenslets illuminated by each projection optic 14. Multiple light field projectors can be tiled together to form a light field display. In this case, multiplexing can be achieved using various techniques. In one embodiment, the projector includes multiple multiplexers, each connected to various optical components of the system (i.e., pixel formers, light field projection lenses, folding prisms, etc.), all multiplexing simultaneously at the same frame rate. In another case, multiplexing can be achieved at increased frame rates by simultaneously operating the same internal optical components (i.e., pixel formers, light projection lenses, folding prisms, etc.) with two or more different multiplexers or two or more different multiplexing techniques. Multiplexing of a projector array can also be achieved by multiplexing a common optical component, such as a display lens or display lens array, shared by all projectors in the array.Multiplexing of shared optical components can be achieved by multiplexing actuators or custom devices to shift the optical system a known distance corresponding to the input frame to the display. Multiplexing can also be achieved by deforming the common optical component. Other display-based multiplexing techniques include manipulating the refractive index of the material of the common optical component or adjusting the aperture of the common optical component.

[0170] FIG. 11 shows the ray paths of a light field projector according to the present disclosure, along with the optical components of the projection optics 14. Output light rays 12 from three LEDs 10a, 10b, and 10c form a first projected image 16 that travels through the projection optics 14 to the collimating optics 18. The illustrated collimating optics 18 is a single lens that outputs a second projected image 20 that is directed to the display optics 22, which outputs the light field image 24. The collimating optics 18 can be a light field projection lens. The projector can also include additional internal optical components for further manipulation, diffusion, and / or collimation of the light. One such internal optical component can be, but is not limited to, a piezoelectric actuator, an electrothermal actuator, a magnetic actuator, an electrostatic actuator, or a shape memory alloy-based actuator, which can act as a multiplexer.

[0171] FIG. 12 shows an alternative ray path diagram for a light field projector according to the present disclosure, with the optical components of the projection optics 14 arranged as shown in FIG. 11. Through the projection optics 14, output light rays 12 from a series of three LEDs 10a, 10b, and 10c project a first projected image 16 onto the collimating optics 18. The collimating optics 18 includes multiple lenses or optical components, shown here as a collimating lens array 26 and a diffuser 36. The collimating optics 18 outputs a second projected image 20 that is directed toward the display optics 22, which outputs a light field image 24. The projector can also include additional internal optical components for further manipulation, diffusion, and / or collimation of the light. One of these internal optical components can be, but is not limited to, a piezoelectric actuator, an electrothermal actuator, a magnetic actuator, an electrostatic actuator, or a shape memory alloy-based actuator, which can act as a multiplexer.

[0172] FIG. 13 shows a further alternative ray path diagram for a light field projector according to the present disclosure, with the optical components of the projection optics 14 arranged as shown in FIGS. 11 and 12. Through the projection optics 14, output light rays 12 from a series of three LEDs 10 a, 10 b, and 10 c project a first projected image 16 onto a collimating optics 18, which includes multiple lenses or optical components that output a second projected image 20 directed to the display optics 22, which output the light field image 24. In this configuration, the collimating optics 18 consists of a collimating lens array including multiple collimating lenslets 32 that output collimated light beams 30 to a diffuser 36, which can be a diffuser array or an optical diffuser. The diffuser can be an optical system or other optical component that outputs the second projected image 20 directed to the display optics 22, which output the light field image 24. The projector may also include additional internal optical components for further manipulation, diffusion, and / or collimation of the light. One such internal optical component may be, but is not limited to, a piezoelectric actuator, an electrothermal actuator, a magnetic actuator, an electrostatic actuator, or a shape memory alloy-based actuator, which may act as a multiplexing device.

[0173] FIG. 14 shows a nominal point spread function for a lenslet in a diffuser according to one embodiment of the present disclosure. In one example, the point spread function 40 can have a FWHM of twice the angle between two directional pixels. A graphical representation of the angular spread of a pixel, with respect to azimuthal angle 42 and polar angle 44, versus light beam intensity 46 as a function of the diffuser is shown. In the projectors described herein, light characterized by a specific throw ratio is emitted from the projection optics, and each pixel in the projected image increases in size proportionally to its neighbors, eliminating pixel overlap. The output of the projection optics is then collimated in a collimating lens array to maintain the projected size of the image. The collimated beam then enters a diffuser, where the beam width is approximately equal for both optics. Finally, the pixel with point spread function 40 from the diffuser enters the back surface of the display optics, which constitutes the display lens. The distance between the display optics and the collimating optics allows for fine tuning of the pixel output width for each image. The position of the pixel produced by multiplexing, i.e., the multiplexed pixel, must be determined so that the multiplexed pixel points to image data corresponding to the correct location, indicating where the input image frame will be rendered. Generally, small movements of precise amounts (i.e., distances of 1 / 4 pixel pitch or 1 / 2 pixel pitch) are required. These may be longer distances, but this should be recognized.

[0174] The location of the multiplexed pixels is determined by the multiplexing method, and the specifications of the multiplexing component or device can be used to determine the location of the multiplexed pixels. This can take the form of calibration of the display to map pixels as part of a light field correction routine. In this case, the location of the multiplexed pixels is determined from simulation and / or calculation.

[0175] 15 shows an isometric view of a light field image display comprising an array of light field projectors as described herein. The illustrated system has multiple light field projectors secured within a light field image display housing with side rails 54. The system is preferably controlled by a printed circuit board (PCB) architecture 56. Display optics 22 output the light field image and are secured to the light field projection system by display lens mounts 48.

[0176] FIG. 16 is an exploded view of a light field image display or system having an array of light field projectors. The system includes a PCB architecture 56. The power and cooling system is housed in side rails 54, which also have fan mounts for cooling the system. The PCB array 52 is powered and connected to the light field projector array 50 by projector mounts 58. The display optics 22 output the light field image and are secured to the light field projection system by display lens mounts 48. In the illustrated embodiment, the light field image display has 18 rows and 12 columns of light field projectors, for a total of 216 light field projectors in the array. Other array sizes are possible, and arrays of any size are possible. In one operating configuration of the light field image display or system of the present invention, the display optics 22 is 187 mm high and 228 mm wide, approximately the size of a small tablet.

[0177] FIG. 17 shows an alternative configuration of a light field projector with a projector array that includes multiple 3x4 projectors within a single projector body.

[0178] Figure 18 shows an alternative configuration of a light field projector, including an array of display devices and all the optics to create a light field display. This system can be tiled / stacked to create a larger light field display.

[0179] 19 shows a block diagram of the present disclosure. A backplane 84 transmits video and control data from an input device to a light field projector 96. A display panel controller 86 generates video input to a display panel 90 by sending an enable signal to a light source driver 88 in a frame sequential driving method, supplying power to the light source LED 10. In the projector, light from the light source LED 10 enters the display panel 90 and is projected onto the display optical system 22.

[0180] Figures 20A and 20B show pixel allocation within a projector frame for the active image, overlap region, and correction buffer. In some embodiments, the projector includes a custom-designed edgeless optical LFP lens 98 that wraps around the front edge of the projector, as shown in Figure 20A. Figure 20A shows a first projected image 16 from an LED light source 10 passing through the LFP lens 98. The LFP lens 98 acts as a collimating optic 18, outputting a second projected image 20. This edgeless design eliminates tiling artifacts in light field displays caused by projector alignment and lens array assembly tolerances. The size of each projector's projected light field image 24 allows for the elimination of display artifacts due to tiling of projectors within the system and allows for digital correction of the light field display. The following diagram shows the ray paths through the LFP lens 98 and illustrates how each projector's pixels are used in the light field display. Figure 20B shows the projected light field image 24 with the overlap pixel 92 assigned, focusing on the correction pixel 94 and the light field image pixel. Figure 20A also shows a side view of the overlap pixel 92 and the correction pixel 94.

[0181] Another embodiment of the present disclosure is directed to a flat-panel-based multiplexed display, which can include, but is not limited to, liquid crystal display (LCD) or light-emitting diode (LED) technology, or a combination of both as a multiplexed autostereoscopic and high-angular-resolution light-field display. Light-field displays can be viewed with both horizontal and vertical parallax, and multiplexing is used to increase the effective resolution in one or two dimensions and improve display quality.

[0182] Projector array-based displays can be challenging to design due to the need to include, at a minimum, many precisely aligned, high-density projectors. Referring to FIG. 21 , a light field display includes an enclosure 104 that houses a projector array 50 and two lens systems: collimating optics 18 or diffusing optics, and display optics 22. The projector array 50 includes multiple projectors, each of which generates light. The projectors in the projector array can be picoprojectors, specialized for augmented reality headsets or automotive heads-up displays (HUDs). The projectors receive image data and convert the image data into projected light. The projected light is then transmitted from the projectors to the collimating optics 18, which may comprise a lens system or array. The light is then transmitted from the collimating optics 18 to the display optics 22, which form a multiplexed light field image. All opto-mechanical components are mounted within the lens enclosure 108.

[0183] Generally, light field displays known in the art require very bright projectors. An advantage of the light field display of the present disclosure is that the brightness requirements of the projectors in the projector array 50 are reduced. This is achieved by designing the lens system of the direct projection display with the ability to control the angular distribution of light and by applying a point spread function to the light beam. Reducing the brightness requirements of the projector array 50 allows the use of smaller LEDs without internal cooling requirements. Therefore, the smaller projector footprint can lead to a tighter packing density of the projector array 50, reduced size and weight of individual projectors, and reduced power requirements for the direct projection light field display. The collimating optics 18 can be a collimating array, which reduces the divergence of light emitted from the projector array 50. The collimating optics 18 is positioned at a throw distance from the projector array 50. In one embodiment, this throw distance is such that the size of each pixel in the projected image increases proportionally to adjacent pixels and there is no pixel overlap. The projectors are positioned such that the distance between the projectors and collimating optics 18 produces a projected image of a size equal to that of a single lenslet in collimating optics 18. The divergence pattern from projector array 50 is approximately the same size as a single projector, and the ratio of collimating optics 18, which may be constructed from collimating array lenslets, to each projector in projector array 50 can be 1:1.

[0184] FIG. 22 illustrates one embodiment of a light field display according to the present disclosure. The collimated light beam exits the collimating optics, which in this embodiment includes a collimating lens array 26 and a diffuser 36. The diffuser 36 can be an optical diffuser array. The diffuser 36 is located between the collimating lens array 26 and the display optics 22 and receives the light from the collimating lens array 26. The collimating lens array 26 and the diffuser 36 can be a single, integrated component or separate components, both of which form the collimating optics 18. The display optics 22 can be positioned to receive the diffused collimated beam from the collimating optics 18. Thus, the light from the collimating lens array 26 travels to the diffuser 36, which in one embodiment is an optical diffuser lenslet array. The output of the projector is collimated to maintain the projected size of the image.

[0185] In the diffuser 36, the divergence of each pixel is increased by the factor: √(C 2 f m 2 ) where C is a constant chosen to properly reconstruct the sampled wavefront, and f m is the fill factor. In one embodiment, the value of C is approximately 2. In such a case, the fill factor f m is approximately 0.9, and the spot size x s is the pixel spacing x p is related to the following equation: x s =x p ·√(C 2 f m 2 ) where x p is the lens pitch divided by the number of angular samples. Thus, the diffuser 36 imposes a point spread function on each pixel in the image. Figure 14 is a graphical representation of the point spread function mentioned above.

[0186] The pixels with the point spread function from the diffuser 36 then enter the back surface of the display optics 22, which constitutes the display lens. The distance between the display optics 22 and the collimating optics 18 allows for fine tuning of the pixel output width for each image, and this distance can be minimized to reduce system space. As light enters and passes through the collimating lens array 26, it is dispersed according to a point spread function, approximated as a Gaussian function. The diffuser 36 can include an angled diffuser or an engineered diffusing lenslet array, used to achieve a desired angle and prevent bleed-through from light projected from adjacent projectors. In one embodiment of the present disclosure, a specific point spread function is applied to the light from each individual projector pixel, and the pixel is oriented at a specific angle. A single projector and its pixels can generate a small image.

[0187] As shown in Figure 22, it can be seen that each projector generates a 26mm x 15mm image at a distance defined by the projector's throw ratio. This image can then be projected onto the collimating lens array 26, resulting in a packet image of that exact size (26mm x 15mm) projected toward the diffuser 36, which can consist of a diffuser screen or optical diffuser lenslet array. The collimating lens array 26, together with the diffuser 36, form the collimating optical system 18. The diffuser 36 can then generate a small, defined point spread function. Using the desired point spread function, proper overlap between pixels is achieved, reducing resolution bias error, or the picket fence effect, and distributing light for a better viewing experience. Resolution bias error is the missing information between samples in a spectrum. Reducing the resolution bias error allows for smooth transitions between viewing regions. The diffuser 36 in this case is designed with a very specific angular output, so that if the designed divergence is, for example, 5 degrees annular FWHM (full width at half maximum), the beam passing through the lens system also has a 5 degree intensity profile. This output is light directed to the display optics 22, which can be a metasurface, a metalens, a gradient index lens material, or any suitable optical component for dispersing light from each pixel according to a plenoptic sampling function as described above.

[0188] Each projector can be aligned so that light exiting the collimating optics 18 strikes the display optics 22 perpendicularly. Therefore, each projector can be equipped with alignment hardware as well as precision controls. Depending on the required tolerances, there are several approaches to aligning the projectors. One approach can use adjustment elements, such as one or more mechanical mounts with screw adjusters, to achieve a coarse alignment at a time. Another approach can provide electronic adjustments at the nanoscale to microscale using piezoelectric transducers. Other adjustment elements can include kinematic mounts, such as the piezoelectric transducers mentioned above, and / or digitally controlled adjustment elements. The maximum amount of adjustment is determined by the dimensions of the lenslets illuminated by each projector. All of these approaches are useful for feedback-based active calibration techniques.

[0189] FIG. 23 illustrates a multiplexing method according to the present disclosure for a light field display. It shows an embodiment of a light field display consisting of a projector array 50, collimating optics 18, and output light beams 12 directed toward display optics 22. The multiplexed light field output 112 projected from the display optics 22 includes two separate light field images, shown as a first set of solid rays and a second set of dashed rays, which together comprise the multiplexed light field output 112. In this configuration, the display optics 22 can be a single lens, a lens array, a pinhole array, a metasurface, a metalens, or any other suitable display optic. Multiplexing can be achieved by shifting the display optics 22 along a first axis 114, a second axis 116, or any combination thereof, using some form of actuator or custom device to shift the optics a known distance corresponding to the input frame to the display. Multiplexing can also be achieved by deformation of the display optics 22, which can occur in 2D or 3D. Other display-based multiplexing techniques include manipulating the refractive index of the materials of the display optics that comprise display optics 22 or adjusting the aperture of display optics 22 with a pinhole array.

[0190] FIG. 24 shows another embodiment of a light field display including a projector array 50 and collimating optics 18, in which output light rays 12 are first directed to an additional multiplexing layer 118 positioned immediately before the display optics 22 and then directed to the display optics 22. The multiplexed light field output 112 projected from the display optics 22 includes two separate light field images, shown as a first set of solid rays and a second set of dashed rays, which together comprise the multiplexed light field output 112. In this configuration, the display optics 22 can be a single lens, a lens array, a pinhole array, a metasurface, a metalens, or any other suitable display optics. While multiplexing can be achieved by all of the methods previously disclosed, such as in FIG. 23, in addition to this configuration, multiplexing can also be achieved by applying an electric field or voltage to a material to actively change the refractive index of the additional multiplexing layer 118, thereby shifting pixel locations by a known pixel distance to increase the effective 2D resolution.

[0191] FIG. 25 illustrates one embodiment of a multiplexed flat-panel light field display. This light field display embodiment includes a flat-panel display 120, collimating optics 18, and output light beams 12 directed toward display optics 22. The flat-panel display 120 can be, but is not limited to, an LED, LCD, plasma panel, or electroluminescent panel. The light-emitting diodes (LEDs) can be organic light-emitting diodes (OLEDs), quantum dot light-emitting diodes (QLEDs), or other suitable diodes. The multiplexed light field output 112 projected from the display optics 22 includes two separate light field images, shown as a first set of solid rays and a second set of dashed rays, which together comprise the multiplexed light field output 112. In this configuration, the display optics 22 can be a single lens, a lens array, a pinhole array, a metasurface, a metalens, or any other suitable display optical component. Multiplexing can be achieved by shifting the display optics 22 along a first axis 114, a second axis 116, or a third axis 122, or any combination of the three. Multiplexing can also be achieved by deformation of the display optics 22, which can be done in 2D. Other display-based multiplexing techniques include manipulating the refractive index of the display optics material that comprises the display optics 22 or adjusting the aperture of the display optics 22 with a pinhole array. Aperture-adjusting multiplexing schemes can be achieved in 1D or 2D using liquid crystal arrays, etc.

[0192] FIG. 26 illustrates another embodiment of a multiplexed flat-panel light field display. This embodiment includes a flat-panel display 120 and collimating optics 18. Output light beams 12 are first directed to an additional multiplexing layer 118 positioned immediately before the display optics 22, and then directed to the display optics 22. The multiplexed light field output 112 projected from the display optics 22 includes two separate light field images, shown as a first set of rays indicated by solid lines and a second set of rays indicated by dashed lines, which together comprise the multiplexed light field output 112. In this configuration, the display optics 22 can be a single lens, a lens array, a pinhole array, a metasurface, a metalens, or any other suitable display optics. Multiplexing can be achieved by any of the methods previously disclosed, such as in FIG. 25, but in addition to this configuration, multiplexing can also be achieved by modifying the refractive index of the additional multiplexing layer 118. This can be achieved in both 1D and 2D.

[0193] A number of embodiments have been described. However, it will be understood that various modifications can be made without departing from the spirit and scope of the invention. For example, some of the steps described above may be order independent and therefore may be performed in an order other than that described.

[0194] The disclosures of all patents, patent applications, and publications referenced herein are specifically incorporated by reference in their entireties to the same extent as if each individual patent, patent application, publication, and database entry was specifically and individually indicated to be incorporated by reference. While the present invention has been described with reference to certain specific embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit and scope of the invention. All such modifications as would be apparent to those skilled in the art are intended to be included within the scope of the following claims.

Claims

1. A projector, a light source comprising a light emitting diode (LED); A projection optical system, at least one illumination optic that receives light from the light source and directs the light into a single optical path; a pixel forming device that receives light from the illumination optics and converts it into a pixel array; a projection optical system including a magnification optic that receives the pixel array; a collimating optical system for collimating light from the pixel array to produce a collimated projection image; a display optical system including a display optical component; a multiplexing device connected to at least one of the illumination optics, pixel formation device, magnification optics, and display optics, and configured to shift the light ray paths to provide a multiplexed light field output.

2. The projector of claim 1 , wherein the illumination optics comprises at least one of a plano-convex lens, a dichroic mirror, a microlens array, a meniscus lens, a bi-convex lens, a single prism, and a folded prism.

3. 3. The projector of claim 1, wherein the pixel forming device is a liquid crystal on silicon (LCOS) panel or a digital micromirror device (DMD).

4. 4. A projector according to claim 1, wherein the magnifying optic is a projection doublet or a biconvex lens.

5. 5. The projector of claim 1, wherein the collimating optics comprises at least one of a light field projection (LFP) lens, a biconvex lens, and a collimating lens array including a plurality of collimating lenslets.

6. 6. The projector of claim 5, wherein each collimating lenslet of the plurality of collimating lenslets comprises two plano-convex lenses.

7. 7. The projector of claim 1, wherein the display optics comprises at least one of a single lens, a lens array, a pinhole array, a metasurface, and a metalens.

8. 8. A projector as claimed in any one of claims 1 to 7, wherein the multiplexing device comprises a voltage generator connected to a first electrode and a second electrode, the first electrode and the second electrode being attached to the multiplexing device of illumination optics, pixel formation devices, magnification optics or display optics capable of producing the Kerr effect.

9. 8. A projector according to claim 1, wherein the multiplexing device is a multiplexing layer located in front of the display optics.

10. 8. A projector according to claim 1, wherein the multiplexing device is a multiplexing actuator.

11. 11. The projector of claim 10, wherein the multiplexed actuators are piezoelectric, electrothermal, magnetic, electrostatic, or shape memory alloy-based actuators.

12. 12. The projector of claim 1, wherein the multiplexed light field output includes a first image at a first location and a second image at a second location, the second image being offset relative to the first image by a distance of less than one pixel width.

13. 1. A method for generating a multiplexed light field image, comprising: generating a light beam from a light source along a light beam path; directing the light beam towards a pixel forming device; converting the light beam into an array of pixels; expanding the pixel array to form an expanded pixel array; collimating the enlarged pixel array to generate a collimated projection image; directing the collimated projected image toward display optics to generate a light field output; shifting the ray paths to multiplex the light field outputs to generate a multiplexed light field image.

14. 14. The method of claim 13, wherein the light beam is directed to the pixel forming device by one or more of a plano-convex lens, a dichroic mirror, a microlens array, a meniscus lens, a bi-convex lens, a single prism, and a folding prism.

15. 15. The method of claim 13 or 14, wherein the light beam is converted into pixels by a liquid crystal on silicon (LCOS) panel or a digital micromirror device (DMD).

16. 16. The method of any one of claims 13 to 15, wherein the pixel array is optically magnified by a projection doublet or a biconvex lens.

17. 17. The method of claim 13, wherein the enlarged pixel array is collimated by a light field projection (LFP) lens, a bi-convex lens, or a collimating lens array comprising a plurality of collimating lenslets.

18. 18. The method of claim 13, further comprising the step of shifting the light ray path by applying a voltage to a first electrode and a second electrode, the first electrode and the second electrode being attached to illumination optics, pixel formation device, magnification optics or a multiplexing device of display optics capable of producing the Kerr effect.

19. 18. The method of any one of claims 13 to 17, further comprising shifting the ray path using a multiplexing layer.

20. 18. The method of any one of claims 13 to 17, further comprising shifting the light ray path by moving the position of an optical component within the projector using one or more piezoelectric actuators, electrothermal actuators, magnetic actuators, electrostatic actuators, and shape memory alloy based actuators.

21. 21. The method of claim 13, wherein the multiplexed light field output comprises a first image at a first location and a second image at a second location, the second image being offset relative to the first image by a distance of less than one pixel width.

22. 1. A method for generating a multiplexed light field image, comprising: generating a light beam from a light source along a light beam path; converting the light beam into an array of pixels; expanding the pixel array; collimating the enlarged pixel array to generate a collimated projection image; displaying the collimated projection image to generate a light field output; shifting the ray paths to multiplex the light field outputs to generate a multiplexed light field image.

23. 23. The method of claim 22, wherein the step of shifting the light ray path comprises moving a position of a movable optical element within the projector, applying a voltage to an optical element multiplexer capable of the Kerr effect, deforming a deformable optical element, or placing a multiplexing layer in the light ray path.

Images