System and method for integrating a virtual display system using a vehicle integrated field emission cavity - Patents.com

Abstract

A display system and method for generating a virtual or light field image includes, in some embodiments, a display and a field emission cavity. The field emission cavity modulates the optical depth of the virtual image. In some embodiments, the display system is integrated into a portion of a vehicle. The virtual image can be reflected by the portion of the vehicle to generate an augmented reality (AR) environment for a passenger.

Description

[Technical field]

[0001] This application claims the benefit / priority of application Ser. No. 18 / 066,844, entitled "System and Method for Generating Compact Light-Field Displays through Varying Optical Depths," filed Dec. 15, 2022, the entirety of which is incorporated herein by reference.

[0002] The present invention relates generally to light field displays, and more specifically to a system for creating a compact light field display through a range of optical depths. [Background technology]

[0003] In current society, advances in electronics and microfabrication have led to increasing traction for more immersive light field and / or autostereoscopic three-dimensional (3D) displays. Unlike stereoscopic 3D, light field displays manipulate the wavefront to generate depth perception at a monocular level. This can eliminate accommodation-vergence mismatch and reduce stress on the user's eyes. There have been breakthroughs to achieve more realistic light field experiences, which can be described in four main methods for creating such experiences, each method having its own weaknesses and advantages: super multi-eye display, computational, multifocal, and holographic. Super multi-eye display methods provide light fields in a very compact form, but are limited to very small viewing zones and low resolution. Computational methods increase resolution, but generate haze and temporal flicker artifacts. Holographic methods can suffer from color non-uniformity and fringing or specular artifacts. Multifocal methods are not scalable, but can produce clean images. Also, devices using multifocal methods can be bulky. However, universal in all current methods of light field display are the following problems: wide bandwidth requirements; reliance on expensive and / or advanced components that are not easily mass-produced, such as tunable lenses; poor color uniformity, small field of view or viewing zone, low brightness, haze and diffraction artifacts, limited depth range; and possible need to wear special glasses. These challenges significantly limit the use or manufacture of light field displays in commercial and / or industrial settings. Therefore, what is needed is a complete class of optical methods that, in some embodiments, use a set of reflectors arranged in a cavity to multiplex different liquid crystal displays (LCDs) or different parts of a single LCD onto different optical focal planes. This allows the light field in the cavity to adapt to a certain optical depth before leaving the exit pupil of the cavity, while solving the aforementioned problems associated with other methods of light field display.

[0004] The objective of the present invention is to provide a user with a device that is a compact system that creates a light field display at or through various optical depths. The present invention is intended to provide a user with a device that addresses the aforementioned problems associated with current methods of light field display. The present invention is intended to provide a user with a device that is less expensive and easier to manufacture at or for a commercial and / or industrial level. The present invention is intended to provide a user with a device that reduces artifacts without reducing the clarity of the light field display. The present invention is intended to provide a user with a device that allows a user to generate content for a light field display more easily than a conventional stereoscopic display. The present invention is intended to provide a user with a device that does not require additional accessories or specialized components (e.g., specialized glasses or a rendering engine) utilized by the user to view the content of the light field display. The present invention is intended to provide a user with a device that can reduce the optical path difference to each focal plane of the light field display and minimize light loss from polarized light. The present invention is intended to provide a user with a device that can change the display focal plane without any mechanical movement. Summary of the Invention

[0005] The present invention is a system for creating a compact light field display through various optical depths. The present invention primarily includes a housing. The housing includes multiple panels in various arrangements that allow the present invention to generate light field displays of various degrees or ranges. The present invention also includes a relay panel. The present invention includes a cover case over the housing.

[0006] To achieve accurate light field displays, advanced optical structures using costly light sources and spatial modulators, such as laser scanners, tunable lenses, liquid crystal on silicon (LCoS) reflectors or digital micromirror devices (DMDs), are usually required. These existing methods therefore do not provide true optical depth. This means that there are inaccuracies in the wavefront in the form of diffractive color inaccuracies, speckles, or haze. One class of display systems and methods revolves around the concept of field emission (FE) cavities. These cavities prepare the light to provide true optical depth without distortion in the wavefront, and therefore the images provided by such systems are as accurate as regular display panels. This method uses conventional LCD or organic light emitting diode (OLED) panel displays in a manner that provides multiple optical focal planes simultaneously or sequentially, in opaque or intensified (transparent) devices. The system can also be conveniently packaged in a small form factor well suited for desktop applications. There is no need for a complex rendering engine, as the cavities provide regular two-dimensional (2D) images and optically combine them into a 3D light field. The method is also scalable to large-scale displays for commercial use. [Brief description of the drawings]

[0007] The patent on file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

[0008] The following description, with reference to the accompanying drawings, illustrates in greater detail aspects of embodiments of the disclosed apparatus, methods and systems, by way of example, which are intended to be non-limiting and illustrative. [Figure 1]FIG. 1 illustrates a light field display based on a three-layer field emission cavity; a non-limiting example of a 3D model of a three-layer light field display prototype is shown, with a front view shown on the left, a rear top view shown in the center, and a front side view shown on the right. [Diagram 2] FIG. 1 shows a generalized block diagram of a cavity-based light field system in the present disclosure. A block diagram of an FE cavity-based light field display system is shown, in which the cavity generates light for multiple focal planes, feeds it to a relay mechanism, and then projects it to the outside world. [Figure 3A] Illustrated is an example of a Class I FE cavity with a primary exit pupil. The display is arranged in one dimension or axis (either vertical or horizontal) and the light for each layer bounces only once from each reflector. This means that there is no round trip or loop that the light goes through before exiting the cavity. Non-limiting examples of different designs under the Class I FE cavity category are shown, from simple layer to more complex multi-layer. [Figure 3B] Illustrated is an example of a Class I FE cavity with a primary exit pupil. The display is arranged in one dimension or axis (either vertical or horizontal) and the light for each layer bounces only once from each reflector. This means that there is no round trip or loop that the light goes through before exiting the cavity. Non-limiting examples of different designs under the Class I FE cavity category are shown, from simple layer to more complex multi-layer. [Figure 3C] Illustrated is an example of a Class I FE cavity with a primary exit pupil. The display is arranged in one dimension or axis (either vertical or horizontal) and the light for each layer bounces only once from each reflector. This means that there is no round trip or loop that the light goes through before exiting the cavity. Non-limiting examples of different designs under the Class I FE cavity category are shown, from simple layer to more complex multi-layer. [Figure 4]Shows an example of a Class II FE cavity with a primary exit pupil, such that Class II displays can be arranged in two dimensions (both horizontally and vertically) to compose the cavity. The term "primary" refers to the fact that light bounces off each mirror or reflector no more than once. A more complex example of a Class II FE cavity showing how multiple displays can be incorporated along two axes to avoid the loss of spatial resolution that occurs when splitting displays within a Class I cavity. The orange arrows are the light flux exiting the cavity pupil. [Diagram 5] Examples of Class I and Class II FE cavities are shown with first and second order exit pupils designed to reduce the optical path difference to each focal plane and minimize light loss; "second order" means that the light may bounce off the reflector up to two times. Examples of FE cavities are shown with higher order exit pupils designed to reduce the optical path difference to each focal plane and minimize light loss by using polarization. [Figure 6] 1 shows an example of an FE cavity with a dynamically translating (mechanically translating) part that is used to adjust or sweep the focal plane through a range of depths. 1 shows an example of an FE cavity with a mechanically translating part that is used to dynamically adjust or sweep the focal plane through a range of depths. [Figure 7] An example of an FE cavity with a switchable mirror element and a switchable diffuser to change the focal depth of the exiting light is shown. An example of a display cavity is shown that uses a switchable mirror (profiles 22, 23 in FIG. 6) and a switchable diffuser (profile 24 in FIG. 6) to change the display focal plane without gross mechanical motion. [Figure 8] An example is shown that uses a switchable liquid crystal layer to switch the path that light takes inside different sections of the FE cavity.An example of an FE cavity is shown that uses a switchable liquid crystal layer to change the display focal plane without any mechanical motion. [Figure 9]Examples of wedge-type (or angled) FE cavities used to generate multiple focal planes are shown, in which the display panel normal vectors may be at angles other than multiples of 90 degrees relative to each other. Examples of compact Class I and II wedge cavities used to generate multiple focal planes in smaller form factors are shown. [Figure 10] Examples are given in which one or all of the depths are shifted using higher index slabs or prisms. It is also shown how prism films can improve the brightness at the focal plane. Examples are given in which materials with different indexes of refraction within the cavity volume or prism films are used to passively adjust or enhance the depth and brightness at the focal plane. [Figure 11] Shown are examples of relay systems used to relay light from the cavity to the outside world. The display can be used as a far-standing display or very close to the head, such as on a desktop. The relays can be fully transparent or opaque, curved or flat, with one piece or multiple switching sections. Shown are how the output of the display cavity can be relayed to a viewer as part of an entertainment system or augmented monitor. The left column shows entertainment system modalities, the right shows augmented near-head display modalities. [Figure 12] We show an example of a compressed FE cavity based on a switchable mirror. The cavity thickness (L) can be reduced by sequentially switching on and off the reflectors. We show how a compressed architecture with a switchable mirror in a class I FE cavity can compress the size of the system. [Figure 13] Shows an exploded view of a prototype model of a three-layer light field display. A 3D model of the prototype system is shown. The left panel is the back of the exploded model, and the right panel is the front of the display, with the light field exiting from the green reflector on top. [Figure 14A]1 illustrates an embodiment in which an aperture optic is placed at the cavity exit pupil of a field emission cavity. [Figure 14B] 1 illustrates an embodiment in which the aperture optic is located at the enclosure exit pupil of the system enclosure. [Figure 15] 1 illustrates an embodiment of a field emission cavity in which elements of the present invention are segmented and configured as a light pipe to generate multiple depths or images. [Figure 16] An embodiment of the invention is shown in which a field emission cavity is in optical communication with a mirror, which produces a virtual image at the same depth as or closer to the viewer's reflection. [Figure 17] 1 illustrates an embodiment of the present invention in which a field emission cavity is integrated into the roof of a vehicle. [Figure 18A] FIG. 17 illustrates various embodiments of a display system, the embodiments using a polarization dependent reflector or semi-reflector. [Figure 18B] FIG. 17 illustrates various embodiments of a display system, the embodiments using a polarization dependent reflector or semi-reflector. [Figure 18C] FIG. 17 illustrates various embodiments of a display system, the embodiments using a polarization dependent reflector or semi-reflector. [Figure 18D] FIG. 17 illustrates various embodiments of a display system, the embodiments using a polarization dependent reflector or semi-reflector. [Figure 18E] FIG. 17 illustrates various embodiments of a display system, the embodiments using a polarization dependent reflector or semi-reflector. [Figure 18F] FIG. 17 illustrates various embodiments of a display system, the embodiments using a polarization dependent reflector or semi-reflector. [Figure 19A] 1 illustrates exemplary ways in which a display system may be integrated within a vehicle, including mechanically articulated or motorized coupling. [Figure 19B]1 illustrates exemplary ways in which a display system may be integrated within a vehicle, including mechanically articulated or motorized coupling. [Figure 19C] 1 illustrates exemplary ways in which a display system may be integrated within a vehicle, including mechanically articulated or motorized coupling. [Figure 19D] 1 illustrates exemplary ways in which a display system may be integrated within a vehicle, including mechanically articulated or motorized coupling. [Figure 19E] 1 illustrates exemplary ways in which a display system may be integrated within a vehicle, including mechanically articulated or motorized coupling. [Figure 19F] 1 illustrates exemplary ways in which a display system may be integrated within a vehicle, including mechanically articulated or motorized coupling. [Figure 20A] 1 illustrates an exemplary application of the disclosed display system and field emission cavity. [Figure 20B] 1 illustrates an exemplary application of the disclosed display system and field emission cavity. [Figure 20C] 1 illustrates an exemplary application of the disclosed display system and field emission cavity. [Figure 20D] 1 illustrates an exemplary application of the disclosed display system and field emission cavity. [Figure 20E] 1 illustrates an exemplary application of the disclosed display system and field emission cavity. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] All illustrations in the drawings are for the purpose of illustrating selected versions of the invention and are not intended to limit the scope of the invention.

[0010] In traditional binocular or stereoscopic vision, a display system provides two offset images separately to the viewer's left and right eyes. These two-dimensional images are then combined in the viewer's brain along with accommodation of the eye lenses to give the perception of 3D depth in front of the viewer. If the true optical depth (curvature of the wavefront) does not match the parallax provided by the stereoscopic image, the viewer experiences a slight, unpleasant inaccuracy. This is because the lenses in his / her eyes tell the brain that the image is at a certain distance, and the parallax tells the brain that it is different. This is known as accommodation-vergence mismatch. Light field display systems modify the wavefront to provide both parallax and accommodation cues. Traditional methods of providing light field displays have been limited by cost, image accuracy, bandwidth, the need to wear a headset or glasses, bulkiness, and manufacturability.

[0011] To overcome this trade-off between perceived content realism and manufacturability, the present invention uses a field emission cavity built around a conventional LCD or OLED panel display to generate digital content at one or more display focal depths, which is then relayed to the outside world. This approach does not require adjustable lenses, powerful computational rendering engines; it does not necessarily rely on freeform optics, can be manufactured cost-effectively, and provides a light field experience to any number of users within a large viewing zone.

[0012] general purpose The present invention provides a multi-layer light field experience with image accuracy comparable to high quality displays in a mass-producible manner. The objective of the present invention is to realize a compact and practical transparent or opaque light field display that does not suffer from accommodation-vergence conflicts and provides true optical depth. Such displays have far-reaching utility in a variety of contexts, as further detailed below. Light fields can be used as entertainment displays for commercial applications or as industrial use cases such as navigation or biomedical use cases. In near-head use cases, the present invention provides a virtual depth or optical space that can appear like a virtual window and provide a sense of scale, despite having a small pupil. For example, the present invention can magnify a 13-inch exit pupil located 10 inches from the head to appear as a 60-inch monitor located 3 meters away from the user.

[0013] In a preferred embodiment, the present invention comprises a system enclosure 5, a field emission cavity 1, and a relay mechanism 3, as shown in Figs. 1-13. The system enclosure 5 is used to house other components of the present invention. Thus, the field emission cavity 1 and the relay mechanism 3 are mounted within the system enclosure 5. The field emission cavity 1 is a compact body that serves to modify the light field display. Furthermore, the field emission cavity 1 comprises a cavity exit pupil 2, at least one display panel 6, and at least one optical tuning mechanism 7. The display panel 6 generates an initial light field display modified by the optical tuning mechanism 7, and then the modified light field display is output by the cavity exit pupil 2. In addition, the display panel 6 and the optical tuning mechanism 7 are configured in a specific optical arrangement that allows at least one light field display 6 to be generated, having at least one focal plane along at least one optical path. The optical path specifically traverses from the display panel 6 to the cavity exit pupil 2. The relay mechanism 3 is used to transfer the modified light field display from the cavity exit pupil 2 to the enclosure exit pupil 4 of the system enclosure 5, such that the cavity exit pupil 2 is in optical communication with the enclosure exit pupil via the relay mechanism 3.

[0014] Figure 1 shows a field emission cavity 1 for a prototype model of the invention. In Figure 1, the cavity exit pupil 2 is also shown in a dotted rectangular frame. The relay mechanism 3 in this case is a simple mirror or a switchable mirror, which relays the cavity exit pupil 2 to an enclosure exit pupil 4. The enclosure exit pupil 4 also allows the light leaving this pupil to reach the user directly without further manipulation. This enclosure exit pupil 4 is shown in Figure 1 in a dashed rectangular frame.

[0015] Technical Description Aspects of the disclosed apparatus, methods, and systems describe various methods, systems, components, and techniques that enable the display of digital content at two or more focal planes, contributing to a significant reduction in the size and cost of light field display systems. The disclosed apparatus, methods, and systems function by generating digital content at multiple depths within a field emitting cavity 1 and relaying this content to a user's eye, as shown in FIG.

[0016] First, digital content is generated within a field emitting cavity 1 at one or more depths. This can be done in a variety of ways, details of which are described in the section entitled "Design of the Field Emission Cavity". A relay mechanism 3 is then used to allow a user to view the digital content in different modalities, details of which are described in the section entitled "Relay Mechanism and Application Modalities".

[0017] Additionally, the techniques described herein may be used in new modalities of near-head displays as well as in large-scale displays such as desktop monitors, television sets, and head-up displays. Details of this application extension are described in the section entitled "Relay Mechanism and Application Modalities." The thickness of the field emission cavity 1 can be reduced by using sequential relays inside and outside the field emission cavity 1, details of which are described in the section entitled "Compression Design." Details of a non-limiting example of a working prototype are described in the section entitled "Prototype Model."

[0018] The invention has four main aspects: (1) the design of the field emission cavity 1 required to generate one or more focal planes from one or more display panels, (2) how to generate various adjustable focal planes (i.e., light fields with adjustable planes) by changing the cavity arrangement or using adjustable mirrors or LCD layers, (3) elaboration of the means to relay light from the cavity exit pupil 2 to the enclosure exit pupil 4, and (4) elaboration of the compression design and near-head use cases.

[0019] Field Emission Cavity Design In order to provide true optical depth to different layers of the light field, an optical mechanism is needed to prepare or manipulate the curvature of the wavefront of light that is true or corrects for that depth. The various embodiments of the field-emitting cavity 1 illustrated in Figures 3-13 are cavities or voids, and comprise at least one display panel 6 (liquid crystal display (LCD), thin film transistor (TFT), light emitting diode array (LED), organic light emitting diode array (OLED), active matrix organic light emitting diode (AMOLED), projection onto a flat screen or other display) and / or at least one mirror 8 and / or at least one half mirror 9 and / or multiple switchable mirrors 13 or at least one liquid crystal cell layer 16, which are arranged and assembled to emit bundles of light with diverging vertices at different depths from the cavity exit pupil 2. These vertices can be from different displays at different depths within the field-emitting cavity 1, or from a single display panel 6 along the entirety of the field-emitting cavity 1. The cavity exit pupil 2 delivers light to a relay mechanism 3, resulting in different or the same reference vertices (depending on the type of relay) of divergence for different focal planes that are presented to the user. The relay mechanism 3 may be a simple flat surface, or a free-form curved surface as further described herein, or a geometric or diffractive waveguide, or any other suitable relay means. The relay mechanism 3 may be translucent, opaque, or with adjustable transparency (e.g., a switchable mirror).

[0020] Since theoretically there are an infinite number of these types of field-emitting cavities, determining the class of the field-emitting cavity 1 is based on the dimensionality of the display configuration. If all of the display panels 6 are aligned along a single axis (e.g., the y-axis), the field-emitting cavity 1 is defined as class I. More specifically, the display panels 6 are aligned along a single axis, which is either perpendicular or parallel to the cavity exit pupil 2. Alternatively, if all of the display panels 6 are aligned in both the x and y dimensions, the field-emitting cavity 1 is class II. More specifically, multiple display panels 6 are aligned along a pair of axes, which are perpendicular to each other, and each of the pair of axes is either perpendicular or parallel to the cavity exit pupil 2. Furthermore, the order of the cavity exit pupil 2 is the maximum number of times that a light beam from any pixel of the display panels 6 is reflected before exiting the cavity exit pupil 2. Any field-emitting cavity 1 having at least one display panel 6 arranged at an angle that is not a multiple of 90 degrees in x and y is still considered a Class II cavity, but is referred to as a Class II wedge cavity or angled cavity. More specifically, the display panel 6 is positioned along an adjustment axis, which is positioned at an angle relative to the cavity exit pupil 2.

[0021] The following description and drawings of Figures 3-13 provide non-limiting examples of Class I field emission cavities that can be used to generate digital content at multiple focal depths using a single display panel 6 or multiple display panels 6 in a parallel arrangement. In all of these configurations, the display panel 6 can use a variety of display technologies, such as OLED, LCD, LED, AMOLED, or any display technology or projection screen that provides a 2D image. In non-limiting examples of these concepts, the display panel 6 can be replaced with a Liquid crystal on silicon (LCoS) spatial light modulator illuminated by continuous RGB light, or a Digital Mirror Device (DMD) spatial light modulator illuminated by a display. Thus, in this disclosure, "display panel" refers to any architecture that provides an array of light that can be focused or collimated to create an image.

[0022] In all of the non-limiting examples and configurations shown in Figures 3-9, the reflector may be a polarization dependent reflector, a semi-transparent reflector, a thin layer pellicle reflector, a beam splitter cube, or other suitable reflector. In all of these configurations, light from different parts of the display panel 6 or from different panels 6 may be polarized to increase the output light efficiency of the light emitting cavity 1. More specific examples are provided in the figures throughout this disclosure.

[0023] 3A, 3B, and 3C show some non-limiting examples of designs for class I of field emission cavities 1. In general, optical tuning mechanism 7 can comprise at least one mirror 8 and at least one beam splitter plate 9. As can be seen from the FIG. 3 section, certain cavity arrangements may be arranged to reflect the light path using mirror 8, and certain cavity arrangements may be further arranged to reflect the light path using beam splitter plate 9, to pass the light path through beam splitter plate 9, or a combination thereof.

[0024] Section 5 of FIG. 3A shows a Class I embodiment of a field-emitting cavity 1 with a single display panel 6 at the bottom, which produces only a single depth (included for theoretical support). Light exits directly from the cavity exit pupil 2 without bouncing off a reflector or other optical surface. This is the zeroth order cavity exit pupil 2. The orange arrows show the light flux exiting the dashed line, which is the cavity exit pupil 6 in all figures of this disclosure. In all figures, only light exiting the light-emitting cavity 1 is shown with red or blue arrows. Light that is wasted is not shown in these drawings for simplicity. Also, for any beam splitter plate 9, the reflectivity percentage can be selected to maximize the brightness uniformity of all layers. This does not change the architecture of the design, and therefore the reflectivity percentage is not specified throughout this disclosure. The reflectivity percentage can be assumed to be 50% for all designs for simplicity.

[0025] Section 6 of FIG. 3A shows an embodiment of a class I field-emitting cavity 1 with a single display panel 6 on the right wall, which generates digital content at two different depths simultaneously. By incorporating a beam splitter plate 9 (half mirror sheet) and a mirror 8, the light is combined and redirected out of the cavity exit pupil 2. Light from the top of the display panel 6 reflects off the mirror 8, passes through the beam splitter plate 9, and half of its intensity is output through the cavity exit pupil 2. Light from the bottom of the display panel 6 reflects off the beam splitter plate 9, and half of its intensity is directed to the cavity exit pupil 2. This is therefore a class I of first order field-emitting cavity 1, with the intensity of each focal plane being half of the original intensity of the display panel 6. In some examples of this type of field-emitting cavity 1, one or more of the reflectors can be shifted up or down to change the desired depth output to the cavity exit pupil 2.

[0026] Section 7 of FIG. 3A shows an extension of section 6 of FIG. 3A, where a single display panel 6 is used to generate digital content at three different depths simultaneously. In some embodiments, the optical efficiency of the field emission cavity 1 may be different for different depths, and therefore the brightness of the display panel 6 may be adjusted to accommodate this variation. For example, if the beam splitter plate 9 has a reflectivity of 50% and a transmittance of 50%, the light from the top of the display panel 6 passes through two beam splitter plates 9 and therefore its intensity is reduced to 25% of the intensity of the display panel 6; the light from the middle section passes through two beam splitter plates 9 and has 25% of the intensity of the display panel 6, while the light from the bottom section only passes through one beam splitter plate 9 and therefore has an intensity of 50% of the intensity of the display panel 6. To compensate for this variation in intensity over the focal depth, the brightness of the bottom can be electronically reduced by 50% via a signal provided to the display panel 6. Such brightness adjustment can be applied to the various configurations of Figures 3-13 to provide uniform brightness to different layers of the light field.

[0027] Section 8 of FIG. 3A shows a final extension of section 6 of FIG. 3A, where a single display panel 6 is used to generate digital content at any number of depths.

[0028] Section 9 of FIG. 3B shows an extension of section 6 of FIG. 3A, in which two field-emitting cavities 1 (each generating content at two depths) are combined to generate digital content at four different depths simultaneously.

[0029] Section 10 of Figure 3B shows an extension of sections 8 and 9 of Figures 3A and 3B, where multiple cavities 1 shown in section 8 of Figure 3A are combined as shown in section 9 of Figure 3B to generate digital content at multiple depths simultaneously.

[0030] Section 11 of FIG. 3C shows an extension of section 9 of FIG. 3, where two display panels 6 are placed back-to-back to provide a more compact form factor.

[0031] FIG. 4 shows a non-limiting example of a design of a class II field emission cavity 1 with a cavity exit pupil 2 .

[0032] Section 12 of Fig. 4 shows an embodiment of a simple class II field emission cavity 1 comprising two display panels 6 arranged perpendicular to each other and combined with a single beam splitter plate 9. The advantage is that the two display panels 6 can generate digital content at two similar depths simultaneously. By adjusting the position of one display panel 6, the depth separation between the two focal planes can be easily adjusted.

[0033] Section 13 of FIG. 4 shows a simple Class II embodiment of a field emission cavity 1 with four display panels 6 that are combined to generate digital content simultaneously at four different depths.

[0034] Section 14 of FIG. 4 illustrates a final extension of section 13 of FIG. 4 to generate digital content at multiple different depths simultaneously.

[0035] Section 15 of FIG. 4 shows an embodiment of a simple class II field emission cavity 1 with four central display panels 6 that are combined to generate digital content simultaneously at four different depths.

[0036] Section 16 of FIG. 4 shows an embodiment of a simple Class II field emission cavity 1 with six display panels 6 that are combined to generate digital content simultaneously at six different depths.

[0037] FIG. 5 shows examples of class I field emission cavities 1 and class II field emission cavities 1 with higher order exit pupils 2. These non-limiting examples show how polarization and multiple reflections from the same surface can produce more compact cavities with a larger number of output focal planes. In general, the optical tuning mechanism 7 can further comprise at least one polarization-dependent beam splitter plate 10 and at least one quarter wave plate 11. As can be seen from the FIG. 5 section, a particular cavity arrangement may be arranged to reflect the light path with a first polarization using the polarization-dependent beam splitter plate 10, to pass the light path with a second polarization through the polarization-dependent beam splitter plate 10, or a combination thereof, where the first polarization is opposite to the second polarization. A particular cavity arrangement may further be arranged to switch the light path from a first linear polarization to a second linear polarization using a combination of the quarter wave plate 11 and mirror 8, where the first linear polarization is perpendicular to the second linear polarization.

[0038] Section 17 of FIG. 5 shows an embodiment of a class II field emission cavity 1 with two polarized display panels 6 combined with a polarization dependent beam splitter plate 10. The polarization dependent beam splitter (PDBS) plate 10 is a beam splitter plate or reflector sheet that fully reflects one polarization and fully transmits the other perpendicular polarization. The advantage is that the two display panels 6 can generate digital content at two similar depths simultaneously. By adjusting the position of one display panel 6, the depth separation between the two focal planes can be easily adjusted. Another advantage is that the light loss is minimized by utilizing the polarization of the display panels 6 in conjunction with the PDBS plate 10.

[0039] Section 18 of FIG. 5 shows an embodiment of a second-order class II field emission cavity 1 that uses a PDBS plate 10 and a wave plate 11 to efficiently generate two different focal planes (image depths). In this embodiment, light from a vertical display panel 6 has horizontal polarization and hits a PDBS plate 10 that reflects only light with horizontal polarization. This light (schematically shown by a red arrow) therefore travels upwards and passes through a quarter wave plate 11 (shown in purple). This quarter wave plate 11 changes the horizontal polarization to clockwise circular polarization, which then hits the half mirror on top of the horizontal display (shown in blue) and reflects it back with counterclockwise polarization. The quarter wave plate 11 converts that counterclockwise circular polarization to vertical linear polarization (schematically shown by a red arrow). This light passes through the PBDS plate 10 and exits through the cavity exit pupil 2. Light from the horizontal display panel 6 has a counterclockwise polarization and is converted to vertical polarization by passing through the quarter wave plate 11 and passes through the PBDS plate 10. This method of using the quarter wave plate 11 along with the reflective surface 8 can be widely used in many other configurations for the field emission cavity 1, as shown in Figures 5-10. The function is the same as that described for this configuration, the wave plate 11, together with the reflective surface 8, reflects and rotates the polarized light by 90 degrees. Thus, if light with horizontal polarization passes through these layers, the light is reflected back with vertical polarization and vice versa. If vertically polarized light reflects off this structure, the light is reflected with horizontal polarization.

[0040] Section 19 of FIG. 5 shows an embodiment of a second-order class II field-emitting cavity 1 that includes a single display panel 6 combined with a series of beam splitter plates 9 and mirrors 8. It has the advantage that a single display panel 6 can be used to generate digital content at two similar depths simultaneously. By adjusting the position of the central beam splitter plate 9, the depth separation between the two focal planes can be adjusted. This embodiment is a class I field-emitting cavity 1 since the display panel 6 exists only in one dimension, and this embodiment has a second-order cavity exit pupil 2 since light from the lower part of the display panel 6 reflects once from the lower beam splitter plate 9 and then again by a half mirror in a horizontal plane (it also passes through the lower beam splitter plate 9 before exiting). Higher-order field-emitting cavities 1 can offer more flexibility in terms of design and form factor, but tend to be less light efficient.

[0041] Section 20 of Figure 5 shows an embodiment of a quadratic class II field emission cavity 1 comprising two display panels 6 combined with a series of PDBS plates 10. Light from the left display panel 6 is x-polarized and is reflected from a reflector 8 to the cavity exit pupil 2. Light from the right display panel 6 is x-polarized, it is reflected downwards, passes through a waveplate 11, hits the bottom mirror 8, passes through the waveplate 11 again, shifting the polarization to y-polarization, and then passes through the PDBS plate 10.

[0042] Section 21 of Figure 5 shows an embodiment of a second-order Class II field emission cavity 1 in which light from the right display panel 6 is configured to be x-polarized, such that the light reflects off the PDBS plate 10. Light from the bottom display panel 6 passes through waveplate 11 with its polarization rotated, through the angled PDBS plate 10 to the cavity exit pupil 2. Light from the right display panel 6 is reflected downwards off the PDBS plate 10, rotates the polarization off the waveplate 11, is partially reflected off the bottom beamsplitter plate 9, and then passes through the angled PDBS plate 10 to the cavity exit pupil 2.

[0043] 6, the optical tuning mechanism 7 may further comprise at least one mechanical actuator 12. As can be seen from the section of FIG. 6, a particular cavity arrangement may be arranged to translate the display panel 6 using a mechanical actuator 12 and / or a particular cavity arrangement may be arranged to translate the waveplate 11 and mirror 8 combination using a separate mechanical actuator 12.

[0044] Section 22 of FIG. 6 shows an embodiment of a Class I field emission cavity 1 with a single display panel 6 that is swept through multiple physical positions to generate digital content at multiple depths. This field emission cavity 1 can be used as part of an adaptive display panel 6, where the position of the display panel 6 is adjusted to correspond to the user's convergence depth, and can be continuously swept while continuously updating the displayed digital content (to generate a light field), or can simply be set to match the perceived depth of the digital content if the digital content is at a known depth. This mechanical motion can be combined with a curved relay to increase the optical range of depth variation. This is usually necessary since mechanical translations with a wide range are usually not practical. Various means such as mechanical stages, piezoelectric transducers, or voice coils can be considered for these mechanical transformations.

[0045] Section 23 of FIG. 6 shows an embodiment of a field emission cavity 1 that combines the embodiment shown in section 22 of FIG. 6 and the embodiment shown in section 17 of FIG. 5, which simultaneously generates digital content at two different depths, one of which is dynamically adjustable.

[0046] Section 24 of FIG. 6 shows an extension of section 23 of FIG. 6, including a movable mirror 8 to allow for more rapid movement of the dynamically adjustable focal plane. Digital content is generated simultaneously at two different depths, one of which is dynamically adjustable. Generally, the speed of depth movement is slower when mechanical motion is used, although faster movement can be achieved by using a higher order field emission cavity 1. The translation speed is typically a direct function of the order. An example of section 24 of FIG. 6 is a doubled adjustability or speed of movement, as light hits the right mirror 8 and returns to a delta deformation of the position of the mirror 8, or the display panel 6 is doubled through the round trip of light. The simultaneous movement of the right display panel 6 and the left mirror 8 can quadruple the speed and range of depth deformation in this example.

[0047] 7, the optical tuning mechanism 7 may further comprise a plurality of switchable mirrors 13 in serial optical communication with one another and positioned offset from one another. As can be seen from the section of FIG. 7, a particular cavity arrangement may be arranged to selectively alternate between reflecting the optical path with at least one particular mirror from the plurality of switchable mirrors 13 and passing the optical path through the particular mirror.

[0048] Section 25 of FIG. 7 shows an embodiment of a field emission cavity 1 that utilizes a polarized display panel 6 and a stack of polarization-dependent switchable liquid crystal mirrors 13 to generate digital content at multiple depths, each of which is determined by which switchable mirrors 13 (those that reflect light) are activated. There are many technologies that provide functionality for the switchable mirrors 13, a non-limiting example of a switchable mirror 13 is a liquid crystal cell (LCC) placed on top of a polarization-dependent reflector. If the incident light has the same polarization as the polarization axis of the reflecting surface, the light reflects off the switchable mirror 13. When the LCC is turned on, such that the LCC cross-polarizes the incident light with the reflecting polarizer, the light passes through and the mirror becomes transparent. There are other technologies that use photorefractive or other electro-optical materials for the switchable mirror 13.

[0049] Section 26 of FIG. 7 shows a variation of section 25 of FIG. 7, which utilizes a folded structure to double the depth separation provided at the output focal plane compared to the physical separation of the switchable mirrors 13. The depth exiting the cavity exit pupil 2 is defined by which switchable mirrors 13 are turned on to reflect light. These switchable mirrors 13 can be switched on and off at speeds comparable to the switching speed of liquid crystal materials (tens of nanoseconds). In this architecture each frame can be reflected from a different depth from the field-emitting cavity 1, and therefore different layers in the light field can be electronically and sequentially scanned. Sequential scanning of layers by turning on one of the switchable mirrors 13 at a time is not necessarily the most efficient way to scan the entire depth of the light field, but computational techniques can be used to turn on and off the switchable mirrors 13 in the field-emitting cavity 1 in such a way as to increase the overall light efficiency or brightness of the depths used. For example, if there is content only at the closest depths, there is no need to allocate more empty frames to different deeper depths. In other words, the signals supplied to the display panel 6 and the switchable mirror 13 can be processed in such a way as to dynamically maximize the frame rate and brightness at the active depth.

[0050] Section 27 of FIG. 7 shows an embodiment of a field-emitting cavity 1 that uses a microlens array to collimate the display panel 6 and projects digital content onto a stack of switchable diffusers. This embodiment produces digital content at multiple depths, each of which is determined by which diffusers are set to be diffusive. Furthermore, if the switchable diffusers are driven such that spatially varying diffusion is achieved, it is possible to produce a diffusing surface that is non-planar, thereby producing an output focal plane that is non-planar. The spatially varying depth of this output focal plane can then be dynamically adjusted to match the spatially varying depth of the digital content being displayed. There are many technologies available for switchable diffusers, most of which rely on polymer stabilized cholesteric texture (PSCT) light shutter technology. Another way to realize section 27 of FIG. 7 is to use a polarization dependent diffuser that scatters light with one polarization and transmits light with the other perpendicular polarization. This requires a layer of liquid crystal on top of the lenslets to rotate the polarization, which corresponds to different diffusers that diffuse light at different depths. While this is theoretically feasible, such an arrangement is most likely to produce haze artifacts for deeper layers.

[0051] 8, the optical tuning mechanism 7 includes at least one liquid crystal cell layer 16. As can be seen from the section of FIG. 8, the particular cavity arrangement is arranged to switch the light path from a first linear polarization to a second linear polarization using the liquid crystal cell layer 16, to adjust the refractive index of the light path using the liquid crystal cell layer 16, or a combination thereof, where the first linear polarization is perpendicular to the second linear polarization.

[0052] Section 28 of FIG. 8 shows an extension of section 25 of FIG. 7, which creates different depths by birefringence of a transmissive liquid crystal cell layer 16 placed on top of the display panel 6. As more or less of the stack of liquid crystal cell layers 16 are activated, the apparent refractive index between the display panel 6 and the cavity exit pupil 2 can be dynamically adjusted. This extension can therefore create digital content at multiple different depths. The amount of required variation of the refractive index depends on the design of the optical relay mechanism 3 that couples to the cavity exit pupil 2. If the optical relay mechanism 3 expands the perceived depth, small variations in the optical path can result in large shifts in the focal plane depth perceived by the user.

[0053] Section 29 of FIG. 8 shows an alternative to section 28 of FIG. 8, which, compared to section 25 of FIG. 7, can provide significantly larger depth steps and therefore a larger depth variation range for the focal plane. This is an embodiment of a class I field emission cavity 1 with a single polarizing display panel 6, where light passes through a liquid crystal cell layer 16 that can rotate the incident polarization. As shown in FIG. 8, due to the remaining structure of the field emission cavity 1 (with the polarization dependent beam splitter plate 10 and the quarter wave plate 11 / mirror 8), it is possible to switch between two output depths using a liquid crystal cell (LCC) layer 16. In some embodiments, the LCC layer 16 does not have a 2D matrix on it, but is an LCC layer 16 that rotates the polarization by 90 degrees once biased. Thus, digital content can be generated in two different planes, the choice of which is determined by the state of the liquid crystal cell layer 16 (and the physical structure of the cavity). In the embodiment shown, the display panel 6 generates horizontally polarized light (blue arrows). When the LCC layer 16 is off, the light passes through the LCC layer 16 with the same polarization, then passes through the polarization dependent beam splitter plate 10, then hits the quarter wave plate 11 and reflector 8, then reflects with vertical polarization, then hits the beam splitter plate 9 and exits the cavity exit pupil 2 (Beam I). When the LCC layer 16 is on (electrically biased), the polarization rotates 90 degrees, becomes vertical, reflects off the beam splitter plate 9, goes upwards, reflects off the quarter wave plate 11 / mirror structure 8, resulting in horizontal polarization, and passes through the polarization dependent beam splitter plate 10 (Beam II).

[0054] Section 30 of FIG. 8 shows an extension of section 28 of FIG. 8, which allows one display panel 6 to generate digital content in three different depth planes, the selection of which is determined by the state of the two liquid crystal cell layers 16 (and the physical configuration of the field emission cavity 1). In addition, it can provide significantly larger depth steps, and thereby a larger depth variation range for the focal plane, compared to section 25 of FIG. 7. Each liquid crystal cell layer 16 acts like a 2D optical valve, storing angular information and defining which path the light takes depending on its state of polarization. Based on the state of the LCC layers 16, three depths can be generated: I, II, and III. For example, considering that the display panel 6 has horizontal polarization, in this design, depth I is generated when LCC1 is on (LCC2 is not used for depth I). Depth II is generated when LCC1 is off and LCC2 is off. Depth III is generated when LCC1 is off and LCC2 is on. In theory this design can be extended to an infinite number of field-emitting cavities, but each time another field-emitting cavity is added, some of the light is lost, reducing the efficiency.

[0055] Section 31 of FIG. 9 shows a compact wedge cavity extension of section 12 of FIG. 4, using a single display 6 instead of two display panels 6 to generate digital content at two similar depths simultaneously. By adjusting the position of the single polarization dependent beam splitter plate 10, the depth separation between the two focal planes can be easily adjusted. Also, by utilizing the polarization of the display panel 6 in conjunction with the polarization dependent beam splitter plate 10 and wave plate 11, an advantage is that light loss is minimized.

[0056] Section 32 of Figure 9 shows a compact class II variant of section 12 of Figure 4, which uses two polarizing display panels 6 and a polarization dependent beam splitter plate 10 to generate digital content simultaneously at two similar depths. By adjusting the position of the display panels 6, the depth separation between the two focal planes can be easily adjusted.

[0057] Section 33 of Figure 9 shows a compact Class I wedge for a field-emitting cavity that uses a polarized display panel 6 to generate digital content at two depths simultaneously. The angle allows light to exit the cavity exit pupil 2 at a desired angle.

[0058] Depth and brightness enhancement mechanism The depth of each layer in the light field can be tailored by using glass or other high index materials in the field-emitting cavity 1 or at the cavity exit pupil 2. Additionally, the brightness of a layer can be increased by using prism films on the display. The display panel 6 in the field-emitting cavity 1 typically has a Gaussian wide-angle profile with a peak intensity at the center, which is not necessarily beneficial in a cavity-based light field where the reflection from the display panel 6 may be at an oblique angle. Placing a prism film on the display panel 6 can help tilt the peak intensity of the Gaussian profile to some desired angle to get a brighter output for that layer of the screen. The reason a high index glass window reduces the depth is because it refracts the light into a smaller cone than the original cone, and therefore the perceived depth appears to be slightly smaller or not as deep.

[0059] 10, the optical tuning mechanism 7 may further include at least one prismatic film 17 and at least one high refractive index material 18. As can be seen from the FIG. 10 section, certain cavity arrangements may be arranged to increase the brightness of the optical path using prismatic film 17, and / or certain cavity arrangements may be arranged to decrease the depth of the focal plane along the optical path using a piece of high refractive index material 18.

[0060] Section 34 of Figure 10 shows an example where prism film 17 can increase brightness by tilting the peak of the Gaussian profile of intensity towards the reflector. Prism film 17 is useful whenever the cavity exit pupil 2 views the display panel 6 at any angle other than 90 degrees.

[0061] Section 35 of FIG. 10 shows an example of a first order Class I field emitting cavity 1 with the cavity exit pupil 2 both of which are perceived as slightly less deep inside the field emitting cavity 1 due to the high refractive index 18 at the cavity exit pupil 2.

[0062] Section 36 of FIG. 10 shows an example of a first order Class I field emitting cavity 1 with a cavity exit pupil 2 where the deeper focal plane is slightly deeper relative to the cavity exit pupil 2 due to the high refractive index 18 on the display panel 6 .

[0063] Section 37 of FIG. 10 shows an example of a first order Class I field emitting cavity 1 with a cavity exit pupil 2 where the deeper focal plane is slightly deeper than the cavity exit pupil 2 due to the high refractive index 18 on the back surface of the reflector 8 at closer depths.

[0064] Section 38 of Figure 10 shows an example of a first order Class I field emitting cavity 1 with a cavity exit pupil 2 where the deeper focal plane is significantly less deep relative to the cavity exit pupil 2 due to the high index of refraction 18 throughout the bottom section of the field emitting cavity 1. Essentially, the bottom reflector 8 is replaced with a high index prism 18.

[0065] Relay mechanism and application modalities As mentioned above, the cavity exit pupil 2 delivers light to a relay mechanism 3 resulting in different divergence reference apexes for different focal planes that are presented to the user. The relay mechanism 3 can be an off-axis visor, a geometric or diffractive waveguide, a birdbath design beam splitter, or any other suitable relay means.

[0066] Figure 11 and the following description provide non-limiting examples of relay mechanisms 3 that can be used to direct the output of a field emitting cavity 1 towards a viewer. In one example, light exits the cavity exit pupil 2 onto a visor and travels towards the eye. In another example, light exits a smaller cavity and is fed into a larger waveguide, which then redirects the light towards the viewer.

[0067] Referring to FIG. 11, a diagram is shown illustrating how the output of the field emission cavity 1 can be relayed to a viewer as part of an entertainment system or augmented monitor. The left column illustrates entertainment system modalities, and the right column illustrates an augmented near-head display modality. Generally, a near-head mount 20 is operably coupled to the system enclosure 5, the near-head mount 20 being used to position the system enclosure 5 adjacent to a user's head. Additionally, an entertainment stand 21 is operably coupled to the system enclosure 5, the entertainment stand 21 being used to position the system enclosure 5 offset from the user's head. Additionally, at least one audio output device 19 is electronically connected to the display panel 6.

[0068] Reference numeral 39 in FIG. 11 denotes a viewer of either the near modality 20 or the entertainment system modality 21, the viewer being more than 60 centimeters (cm) from the display.

[0069] Reference number 40 in FIG. 11 indicates a generalized display cavity (ie at least one field emission cavity 1) for generating digital content (stereoscopic or 2D) at one or more depths.

[0070] Reference number 41 in FIG. 11 denotes the casing of at least one field emission cavity 1 (ie the system enclosure 5) which holds the remainder of the system electronics.

[0071] Reference numeral 42 in FIG. 11 shows an example of an angled reflector relay (i.e., relay mechanism 3) in which a reflective, semi-reflective, or switchable mirror surface is used to relay the cavity exit pupil 2 to the enclosure exit pupil 4, i.e., to the observer.

[0072] Reference numeral 43 in Figure 11 shows an example of a curved angled reflector relay (i.e. relay mechanism 3) in which a curved reflective, semi-reflective or switchable mirror surface is used to relay the cavity exit pupil 2 to the enclosure exit pupil 4, i.e. to the observer. The curvature of this relay can vary the depth of the content coming from the original depth of the cavity to a greater or closer distance.

[0073] Reference numeral 44 in FIG. 11 denotes a coupling optic that couples the cavity exit pupil 2 to the entrance pupil of the waveguide (ie, the relay mechanism 3).

[0074] Reference numeral 45 in Fig. 11 denotes geometric or diffractive waveguides (i.e., relay mechanism 3) that redirect the output of the FE cavity (made of an array of LCoS and reflectors or DMD and reflectors or LCD panels and reflectors or projectors) to the viewer. These waveguides can be multimode geometric waveguides, diffractive waveguides, or real single mode confinement waveguides.

[0075] Reference numeral 46 in Figure 11 denotes a compression relay system (i.e., relay mechanism 3), which will be described in more detail in the next section of this disclosure. The compression relay system helps to have a more compact form factor for the display.

[0076] Compression Design A single reflector may be bulky both inside the FE cavity 1 and as a relay. Figure 12 shows some non-limiting examples of such compact designs based on spatial stacking of switchable mirrors.

[0077] With reference to Fig. 12, the operable combination of at least one field emission cavity 1 and relay mechanism 3 may comprise a plurality of switchable mirrors in serial optical communication with each other and offset from each other. Furthermore, the plurality of switchable mirrors may include a plurality of first switchable mirrors 14 and a plurality of second switchable mirrors 15, such that the plurality of first switchable mirrors 14 are distributed among the plurality of second switchable mirrors 15. As can be seen from the Fig. 12 section, the particular cavity arrangement is arranged to selectively alternate between reflecting the light path in a first polarization with at least one designated first switchable mirror from the plurality of first switchable mirrors 14 and passing the light path through the designated first switchable mirror, and the particular cavity arrangement is further arranged to selectively alternate between reflecting the light path in a second polarization with at least one designated second switchable mirror from the plurality of second switchable mirrors 15 and passing the light path through the designated second switchable mirror. Thereby, the plurality of first switchable mirrors 14 and the plurality of second switchable mirrors 15 are configured to compress the occupied volume of the operative combination of at least one field emission cavity 1 and relay mechanism 3. Section 47 of FIG. 12 shows an exemplary system in which there is no compression, similar to section 6 of FIG. 3A, with a class I FE cavity 1 and two depths. Light exits the cavity exit pupil 2 (shown in blue dashed line), reflects from reference 42 of FIG. 12 (i.e., relay mechanism 3), and exits the enclosure exit pupil 4 (shown in red dashed line). The deeper light I comes from depth I, and light II comes from a closer distance inside the field emission cavity 1. The system is required to have a minimum thickness of L mandated by the dimensions of the display panel 6. For the same dimensions of the display panel 6, section 48 of FIG. 12 reduces the thickness by half (L / 2). This compression is obtained by means of the temporal switching of switchable mirrors, or by polarization, by having a stack of repeaters which are transparent to one another.Thus, in section 48 of FIG. 12, the deeper depth I has two sections Ia and Ib relayed at two different distances; the distances in the relays work so that Ia and Ib both have the same depth as depth I, but span the same enclosure exit pupil 4 size as section 47 of FIG. 12. The same is happening for the closer depth II. The depth is diced into two relays that extend the enclosure exit pupil 4, but with a thinner thickness. This approach can be extended for further compression. Furthermore, section 49 of FIG. 12 shows the case where the thickness relative to section 47 of FIG. 12 is compressed by a factor of three. Here, each depth level is spatially multiplexed into three sections, compensated by the height of the three relay switchable mirrors 14, 15. For example, the paths that Ia and Ib and Ic travel to the enclosure exit pupil 4 (shown in dashed red lines) are equal, and therefore they all have the same depth as depth I. 12. However, they exit at different heights, expanding the enclosure exit pupil 4 back to the size of the enclosure exit pupil 4 of section 47 in FIG.

[0078] Prototype example Figure 13 shows an exploded 3D model of the prototype system, which is not shown in detail in Figure 1, and has three depths, from rear to left and front to right. The parts are:

[0079] Reference number 50 in FIG. 13 (i.e., a component of the system enclosure 5) is a side holder of the assembly. Reference number 51 in FIG. 13 (i.e., a component of the optical tuning mechanism 7) is a reflective or semi-reflective surface. Reference number 52 in FIG. 13 is a simple reflective mirror that functions as a relay mechanism 3. Reference number 51 in FIG. 13 (i.e., a component of the system enclosure 5) is a top cap just to protect the relay mechanism 3. Reference number 54 in FIG. 13 (i.e., the display panel 6) is an LCD panel split into three depths. Reference number 55 in FIG. 13 (i.e., a component of the system enclosure 5) is a back cover of the FE cavity 1.

[0080] Advantages and improvements over existing methods The component arrangement, method, and assembly herein provide various advantages and improvements over existing 3D systems.

[0081] Ergonomic advantages and improvements o Accommodation-vergence conflict mitigation - The invention described herein can generate digital content at multiple depths with true monocular optical wavefronts. The flexibility of displaying digital content at multiple depths allows for presentation of digital content at optical depths that match or resemble the binocular disparity depth cues presented to the viewer, thereby helping to resolve accommodation-vergence conflicts experienced by the viewer. Mitigating accommodation-vergence conflicts makes digital content more comfortable to view over time and enhances the realism experienced by users viewing the digital content.

[0082] o Reduced size - The present invention offers flexibility in terms of packaging compared to systems that use projectors because it allows for folding of the light path. This allows for smaller systems.

[0083] Unlike autostereoscopic 3D systems, where the viewing zone distance and angle are limited and sometimes only a few viewers can see the 3D content, the present invention allows a viewing angle of up to 150 degrees (depending on the number of depths) and has no limit on the number of users.

[0084] The FE cavity 1 can be combined with any type of panel and light engine so as not to be limited to a specific technology, and if necessary, autostereoscopic displays can also be used as engines to increase their performance in depth accuracy.

[0085] o Reduced Cost - In contrast to using eye-tracking based adaptive displays or holographic displays, the present invention can utilize readily available components (flat display panels) that are ready for mass production, significantly reducing overall system costs and technical challenges.

[0086] o Because the FE Cavity 1 system allows for true optical depth, the enclosure exit pupil 4 can be located very close to the eye without eye fatigue, since the true optical depth of the image can be placed far back. Unlike stereoscopic displays, this opens up entirely new possibilities for near-temporal displays, where the size of the display can be expanded without the need to wear anything or have a large screen.

[0087] o For most of the designs herein with passive glass reflectors or even switchable mirrors, the image provided by the FE cavity 1 is free of artifacts such as haze, color non-uniformity, distortion, and moiré artifacts.

[0088] Performance benefits and improvements o Bandwidth Reduction - The invention described herein allows accommodation-vergence conflicts to be resolved or mitigated without the need to present the entire 5D plenoptic function to the viewer. This reduces the complexity of content rendering and can improve system frame rates compared to full light field displays. Bandwidth can be reduced by several orders of magnitude.

[0089] Flexibility in optical efficiency - The present invention is flexible in that if optical efficiency is a priority, designs with high light throughput can be chosen. If display brightness is not required, there is further flexibility to add more display planes or to use simpler cavity designs.

[0090] o Spatial resolution flexibility - The present invention is flexible in that it can maintain spatial resolution by using multiple display panels 6. When spatial resolution is not required (e.g. when individual pixels are not yet resolvable by the user), the present invention can utilize unnecessary spatial resolution to render different depth planes and improve the user experience.

[0091] o Scalability - The FE cavity 1 is advantageously scalable in architecture, number of planes, and extension to different display systems.

[0092] Compatibility - The invention presented here has the great advantage of compatibility, both at the software and hardware level. At the software level, the light source can be the 2D screen at the end, so that the feed to the display system can easily be a conventional standard signal. This also simplifies the rendering, since there is no fundamental need for significant computational processing of the input due to depth providing optics. The hardware architecture is essential for the wide variety of existing 2D display systems.

[0093] ● Functional advantages and improvements o Monitor magnification - The depth of the systems disclosed herein is true optical depth, so the eyes can accommodate and view these 3D contents without discomfort at any given distance of the display. For example, if the display is 20cm away from the head, but the depth shown is still 2 meters, the viewer will perceive the image as 2 meters away and be able to use the monitor even at such a close distance. This is useful for magnifying small monitors using the true optical depth provided by the disclosed systems.

[0094] Head-up displays - Since the depth can be much farther than the actual position of the display, relays can be made semi-transparent, making them a perfect case for large-scale overlay of images with the real world, especially in the context of head-up displays.

[0095] Entertainment - The Light Field experience provides better immersion with accurate optical depth and artifact-free images. It can be used for home entertainment, gaming, and commercial entertainment applications.

[0096] Commercial Applications Many commercial uses become possible with dramatic precision in depth, screen transparency, and immersion. Below is a non-exhaustive list of possible applications:

[0097] Navigation * Turn-by-turn directions while driving / steer / etc. use the heads-up display without looking at the road or getting lost on a phone or another navigation device.

[0098] Medical Better exploration of 3D data files using Light Field Display.

[0099] Workplace ergonomics o The magnified display can replace the larger display without the need to install any hardware or have a larger screen. The 3D nature of the display can provide volume for office work with pixel accuracy equal to today's standard monitors.

[0100] Entertainment The layered nature of the FE cavity 1 facilitates content generation from the gaming and video industry, as rendering in several layers to provide a 3D effect is much easier (less computationally demanding) than rendering an entire 3D environment.

[0101] 〇FE Cavity 1 is well suited for standalone game consoles, as true depth engages the audience with a new experience.

[0102] ●Design Preview the look and feel of objects that have not been physically prototyped and visualize content for modeling and design in AR or VR without the need to wear a headset, which is crucial as developers cannot wear a headset for hours, but can use the invention with true optical depth.

[0103] In any of the field emission cavity embodiments described above, an aperture optical element 70 can be added to assist and modify the optical properties of the light in the optical path. Figures 14A and 14B show two illustrative examples.

[0104] In Figure 14A, light exiting a field-emitting cavity 1 passes through an aperture optical element 70 located at the cavity exit pupil 2. The light, modified by the aperture optical element 70, exits the system enclosure 5 through the enclosure exit pupil 4. Similar to the illustrative example of Figure 14B, the field-emitting cavity 1 emits light through its cavity exit pupil 2. The light passes through, and is modified by, an aperture optical element 70 located at the enclosure exit pupil 4 and proceeds to an observer.

[0105] The aperture optics 70 may include any number of light modifying devices, including, but not limited to, an anti-reflective layer, a prism film 17, a privacy layer, an absorbing polarizer, or a microcurtain layer. The aperture optics 70 may further be used to modify ambient light directed from the external environment to the user. As an illustrative example, an anti-reflective layer may be used as the aperture optics 70 to remove stray light reflections that may enter the observer's eye. The aperture optics 70 may have the additional function of protecting components within the system enclosure 5 from the external environment. In some embodiments, the aperture optics 70 may be located at both the cavity exit pupil 2 and the enclosure exit pupil 4.

[0106] In this disclosure, the field emission cavity can generate a light field display, or a subsampled light field display, i.e., a light field display that approximately replicates only the full light field emanating from a physical three-dimensional scene. For example, a fractional light field display may generate a single virtual image corresponding to a single focal plane or virtual depth.

[0107] In some embodiments, the field emission cavity 1 further comprises one or more semi-reflective elements 71 and one or more reflective elements 72. In some embodiments of the invention, these reflective elements 72 and semi-reflective elements 71 are configured such that the light of the optical path is at least partially folded back on itself to selectively adjust the virtual depth position of the virtual image presented to the viewer. In other words, the field emission cavity 1, the reflective elements 72, and the semi-reflective elements 71 are configured such that a portion of the optical path is folded back on the original optical path to adjust the depth of the focal plane along the optical path. This folding of the optical path on itself allows the invention to further adjust the virtual depth position of the virtual image. Further embodiments include a switchable mirror or a mechanical actuator in the field emission cavity 1 configured to further adjust the virtual depth position of the virtual image.

[0108] 15 shows a further embodiment of a field emitting cavity 1 in which the semi-reflective element 71 of the system is segmented to produce multiple depths through the extended aperture optics 70. In some embodiments, the display panel 6 itself may be segmented. In other embodiments, the reflective optics 72 or the semi-reflective optics 71 may be segmented.

[0109] In this disclosure, a "segmented" element has properties that vary across the surface of the element. A segmented semi-reflective element is, for example, a semi-reflective element that has a varying reflectance coefficient or reflectance across its surface. The variation can be smooth, continuous, piecewise constant, or piecewise smooth. A segmented display panel is a display panel that shows different image content in various regions of the display panel. For example, a display panel segmented into two regions can show a first image and a second image. In this way, light emitted from, transmitted through, or reflected from different segments of a segmented element can travel different paths through the display system.

[0110] This segmentation of components creates several segmented elements, such that the segmented display panel 6 can be segmented into a first segmented element and a second segmented element. There is no limit to the number of segmented parts that can be created by the segmented components. Furthermore, similarly, the reflective 72 optics or semi-reflective 71 optics can also be segmented into a first segmented element and a second segmented element. Any of the components within the present invention can be segmented in this same manner. Exemplary embodiments with segmented elements are shown in Figures 15 and 17.

[0111] Additionally, the reflective 72 or semi-reflective 71 optics can have gradient properties, such as gradient reflectance. The reflective 72 or semi-reflective 71 optics, including segmented optics, may be polarization dependent, such that after interacting with the polarization dependent element, light of a first polarization travels a first optical path and light of a second polarization travels a second optical path.

[0112] As shown in Figure 15, light in the optical path may be directed along a cavity formed between two or more reflectors, elements, optics, or components that make up the light pipe. The light in the light pipe is directed down the cavity of the light pipe where it exits the light pipe through aperture optic 70. The light is directed to an observer.

[0113] In further embodiments, a light pipe can be created using segmented elements, such as a first segmented element and a second segmented element. In one embodiment, the first segmented element and the second segmented element are comprised of polarization-dependent elements. The polarization-dependent elements of the first segmented element and the second segmented element are configured such that light of a first polarization is directed along the light pipe along a first optical path and light of a second polarization is directed along the light pipe along a second optical path. This causes the light pipe to generate multiple virtual images at multiple depths. In some embodiments, optical paths corresponding to different segmented elements form images at the same depth but different lateral positions, so that together they form a single virtual image with an extended aperture or field of view. In some embodiments, the polarization-dependent element light pipe is embedded or integrated into the vehicle.

[0114] A further embodiment shown in FIG. 16 has a field emission cavity 1 with an exit aperture in optical communication with a large mirror 79. The mirror can function in part as an aperture optic. This embodiment further comprises a gesture sensor 80, a depth camera 80, or both. The gesture sensor 80 or depth camera 80 is coupled or integrated with the display system. The gesture sensor 80 or depth camera 80 observes the viewer 77 so that the display system can capture, incorporate, or interpret the movements, positions, and gestures of the viewer 77. The gesture sensor 80 or depth camera 80 relays information about the viewer 77 to the display system. The display system can then use this information to dynamically generate and display text or other augmentation effects as a virtual image 81. In some embodiments, the text or augmentation effects can be generated from other sources and they can be manipulated by the viewer through the depth camera 80 or gesture sensor 80.

[0115] In this embodiment, the field emitting cavity 1 is configured to generate a virtual image 81, which may include any number of items, such as, but not limited to, text or an image. This virtual image 81 is generated by the field emitting cavity 1, such that the virtual image 81 appears at a similar virtual image depth as a reflection 82 of an observer in a mirror. In other words, when an observer looks at their reflection 82 in the mirror, the virtual image 81 generated by the field emitting cavity 1 appears to be at the same depth or in the same plane as the reflection 82 in the mirror.

[0116] In some embodiments, the field emission cavity 1 may further comprise retroreflective or retrorefractive elements. The retroreflective or retrorefractive elements may be configured such that the virtual image 81 appears closer to the viewer 77 compared to the viewer's 77 physical distance to the display. This causes the text or augmentation effects of the virtual image 81 to appear at the same depth as the image of the observer. The viewer may then interact with the virtual image 81 via the gesture sensor 80 or depth camera as if the text or augmentation effects of the virtual image 81 were hovering in mid-air.

[0117] FIG. 17 shows a further embodiment in which the field emission cavity 1 is embedded or integrated into the roof 75 or ceiling of a vehicle 76. In this further embodiment, which is similar to embodiment 33 of FIG. 9, the display panel 6 emits light into the field emission cavity 1, which may have a first element 73 and a second element 74. Both the first element 73 and the second element 74 may be reflective or semi-reflective elements arranged at an angle of less than 45 degrees relative to each other. This angle may be designed arbitrarily. In some embodiments the display panel itself may be segmented, and in some embodiments the first element or the second element may be segmented. In some embodiments the segmented characteristic may be switchable in time such that the light travels a first path at a first time and the subsequent light travels a different path at a second time. In some embodiments there are no segmented elements. As the light is reflected between the two reflective elements the angle the light travels becomes shallower. This creates a light pipe that directs the light from the exit of the display system towards an observer 77 who sees a virtual image 78 corresponding to a shallower line of sight. In some embodiments, the virtual image is tilted at a different angle than any of the components of the display system and the roof or ceiling. A viewer does not see the virtual image when looking straight into the roof of the vehicle. In some embodiments, an aperture optic 70 is used. In some embodiments, a relay mechanism 3 is used. In some embodiments, a component of the display system, such as a second segment element, functions simultaneously as the aperture optics, the relay mechanism, and the optical tuning mechanism, or a subset thereof.

[0118] In some embodiments, the light path may be affected by a polarization-dependent element. For example, the semi-reflective element may comprise a polarization-dependent grating that directs light of a first polarization along a first path and light of a second polarization along a second path. The polarization of the light may be changed using quarter-wave plates and reflective polarizers.

[0119] In some embodiments, the field emission cavity can further include retroreflective or retrorefractive elements so that the virtual image appears closer to the viewer rather than further away. Similar to the embodiment of FIG. 16, a gesture camera or depth sensor can be coupled to the display system so that the viewer can interact with the virtual image. In some embodiments, the display system is transparent or translucent for a see-through effect so that the user can simultaneously see the display content and the environment behind the display system. In some embodiments, a camera captures information about the environment outside the vehicle and the display system displays that information for a video see-through effect.

[0120] The embodiment of Figure 17 is an example of a wedge-shaped cavity as described in Figure 9, but may also be configured as other classes or orders of field emission cavities such that the light path is folded exactly or approximately onto itself. In such cavities, light may be folded as it undergoes multiple reflections from a single element.

[0121] The embodiment of Figure 17 may be integrated into a portion of a vehicle. Although the embodiments described herein depict an automobile or vehicle, the vehicle may take other forms, including, for example, but not limited to, a car, a truck, a motorcycle, a tricycle, a tank, an aircraft, or a watercraft.

[0122] It is important to note that each point of the virtual image is visible by both eyes of a human observer, i.e., light rays from any given point of the virtual image are incident on both eyes simultaneously. The viewer's eyes can be located anywhere within a particular volume to view the virtual image. The depth of the virtual image is the depth to which each eye accommodates or focuses. This volume is called the headbox and spans a lateral dimension. The lateral dimension may be, for example, at least 8 cm, at least 10 cm, at least 15 cm, at least 20 cm, or at least 30 cm. The distance between the display system and the nearest viewing position in the headbox may be, for example, 20 cm, 30 cm, 40 cm, 50 cm, 60 cm, 70 cm, 80 cm, 90 cm, or 100 cm. In some embodiments, the nearest viewing position is greater than 100 cm. This distance is limited in part by the viewing direction required to see the virtual image.

[0123] Also, a virtual image is an image in which the imaging rays corresponding to a given point in the image do not physically intersect. Rather, they are divergent or collimated. When the image-forming rays are geometrically projected backwards, their projections intersect. This intersection point is the location of the virtual image. (In contrast, an image formed by physically intersecting rays is a real image that can be projected onto a screen or other physical surface without any other focusing element.) In some embodiments, a virtual image is observed by an observer.

[0124] In some embodiments, the first element 73 or the second element 74 of FIG. 17 are polarization dependent. In some embodiments, they are semi-reflectors or partial reflectors. For example, the first element 73 may be a polarization-changing semi-reflector, an element that transmits at least a portion of the light incident on it and further converts the polarization of the incident light from one state to another. In some embodiments, the polarization-changing semi-reflector comprises a first wave plate, a beam splitter or other semi-reflector, and a second wave plate. In some embodiments, the wave plate is a quarter wave plate. When linearly polarized light is incident on this polarization-changing semi-reflector, the transmitted light is linearly polarized, but the direction of polarization is rotated by 90 degrees, i.e., the incident x(y)-polarized light is converted to y(x)-polarized light. The linearly polarized light reflected by this element is also rotated by 90 degrees.

[0125] In some embodiments, either element 73 or 74 is a polarization-changing reflector, an element that reflects light incident on it and further converts the polarization of the incident light from one state to another. In some embodiments, the polarization-changing reflector comprises a mirror and a wave plate. The wave plate is, in some embodiments, a quarter wave plate. Incident linearly polarized light is reflected and the polarization direction is rotated by 90 degrees.

[0126] The state of polarization under consideration can be linear, circular, or elliptical. In some embodiments, the degree of polarization is included in the state of polarization.

[0127] In some embodiments, the first element 73 or the second element 74 is a reflective polarizer that transmits light of a first polarization state and reflects light of a second polarization state that is orthogonal to the first polarization state. An example of a reflective polarizer is a wire grid polarizer. In some embodiments, the reflective polarizer is a polarization dependent beam splitter (PBS).

[0128] In some embodiments, the optical properties of the first element 73 or the second element 74 are controlled by electronic signals. For example, the above-mentioned waveplate in the polarization-changing (semi-)reflector may be a liquid crystal (LC), such as a nematic LC or a cholesteric LC. When a first voltage is applied to the waveplate, it transmits light without changing its polarization (thus preserving the polarization), and when a second voltage is applied, it changes the polarization from a first state to a second state, such as converting horizontally polarized light to vertically polarized light. The voltage value can be designed arbitrarily, including 0V. For example, if the first element 73 comprises a first waveplate, a beam splitter, and a second waveplate, and one of the waveplates is a liquid crystal, the applied voltage affects how the polarization of the transmitted and reflected light changes. At one voltage, the transmitted polarization can be rotated 90 degrees; at a second voltage, it can be rotated 0 degrees; at a third voltage, the incident linearly polarized light can be converted to circularly polarized light. Thus, the type of waveplate and the configuration of the LC can affect the transmitted polarization. As a result, the transmitted light interacts differently with the second element 74.

[0129] 18A-18F show a set of embodiments related to FIG. 17. In FIG. 18A, light having a first polarization state is emitted from the display 6 and enters the field emission cavity 1. In all the embodiments shown in FIGS. 18A-18F, the field emission cavity 1 includes a first element 73 and a second element 74, and may include additional optical elements as well as structures for mechanically supporting the elements. Inside the cavity, the light is first reflected from the first element 73, which is a polarization changing reflector. The light is then reflected by the second element 74, which has a reflective polarizer, and then reflected again by the first element 73. The polarization state is such that the light is transmitted by the second element 74 when it enters for the second time. The transmitted light passes through the aperture optical element 70 and exits the cavity to the outside world. In some embodiments, the aperture optical element 70 includes an absorbing polarizer and an anti-reflective layer. In some embodiments, the aperture optical element is a transparent material such as a glass layer.

[0130] When the light is viewed by a viewer, it forms a virtual image 78 that is farther from the viewer than the field-emitting cavity itself. Furthermore, the angle of first element 73 relative to second element 74 is less than 45 degrees, so that the orientation of the virtual image is shallower than relative to the display itself. Furthermore, because the angle is less than 45 degrees, the field-emitting cavity can be made thinner.

[0131] Any electronically addressable or electrically active parts of the display system and cavity are controlled by a circuit block 1801. In some embodiments, the circuit block is coupled to the vehicle's electronic system. In some embodiments, the circuit block is an integral part of the display system and functions to provide the content of the virtual image.

[0132] FIG. 18B shows an embodiment in which the display 6 is substantially parallel to the aperture optical element 70. The display sends light through a first element 73, which may be a polarization-changing semi-reflector. The polarization state is rotated 90 degrees and reflected by a second element 74, which may be a reflective polarizer or PBS, and then reflected by the first element 73, which rotates the polarization by another 90 degrees to be transmitted by the second element 74, and passes through the aperture optical element 70. A virtual image 78 is formed, which is located at a depth further than the field emission cavity 1 and further than the display 6 itself. A circuit block 1801 controls the display content. In some embodiments, the polarization-changing semi-reflector includes a first wave plate, a beam splitter, and a second wave plate. In some embodiments, the aperture optical element 70 includes an absorbing polarizer and / or an anti-reflection element. These are just examples, and any suitable configuration of the first element 73, the second element 74, and the aperture optical element 70 may be used. In some embodiments, a directional coating is introduced into the beam path. The angle between the first and second elements is θ, which is less than 45 degrees.

[0133] In an FEC, light is reflected or circulated back and forth between the elements of the cavity. Each of these propagations is a pass. For example, an FEC can have a first element and a second element. The first instance of light propagating from the first element to the second element is called a forward pass. When the light, or a selected portion of the light, is reflected back from the second element to the first element, the propagation is called a backward pass, since the light propagates backwards toward the light source. In this cavity, a round trip occurs when the light completes one cycle (forward and backward passes) and returns to the first element. In some embodiments, a round trip occurs when the light substantially reverses direction and enters an element more than once. The term "round trip" refers to the number of times that light circulates or bounces back and forth between two elements of the cavity, or the number of times that light interacts with a single element.

[0134] In some embodiments, the light makes one round trip within FEC 1. In some embodiments, the number of round trips may be 2, 3, 4, or 5. The number of round trips substantially determines the monocular depth perceived by the viewer. In some embodiments, the monocular depth is greater than the distance between the observer and the light source. For example, the ratio of monocular depth to distance may be 1.1, 1.5, 2, 2.5, 3, 4.5, or 5. In some embodiments, the ratio may be in the range of 1.1 to 2, 1.5 to 3, or 2 to 5, etc. In some embodiments, the monocular depth is dynamically adjustable by changing the characteristics of the virtual display system.

[0135] In an embodiment such as FIG. 18A, there is one round trip. In the embodiment of FIG. 18B, there are two round trips. Mechanisms for introducing more round trips include modifying the properties of the first and second elements. For example, by using a different type of waveplate or LC in the first element, the reflected polarization (after the first round trip) can be reconfigured so that a majority of the light is reflected a second time by the second element. Furthermore, the second element may also include a polarization modifying element such as a waveplate or LC to modify the polarization of the light it reflects. Furthermore, both the polarization change and the reflectance and transmittance of these elements can be a function of angle. For example, either element can include a multilayer film. In such an embodiment, the angle of the light beam changes with each round trip, so that the light can be substantially transmitted by the second element after reaching the desired angle.

[0136] FIG. 18C shows an embodiment similar to FIG. 18B. Light from the display 6 passes through a pre-cavity element 1804, which in some embodiments includes a directional coating. The directional coating selectively transmits light rays oriented at angles within a particular angular range and blocks light rays directed outside that range. For example, the directional coating can transmit light rays incident within the ranges of 0-10 degrees, 0-20 degrees, 0-30 degrees, 0-40 degrees, 0-50 degrees, or 0-60 degrees. The directional coating does not provide an optical (focused) power source. In some embodiments, the directional coating transmits angular ranges that do not start at zero degrees.

[0137] The light then passes through the first element 73, which is a polarization-changing semi-reflector. The light is reflected by the second element 74, which is a reflective polarizer, and travels back and forth within the field emission cavity 1. The light then exits the system through the aperture optical element 70. In some embodiments, the aperture optical element 70 is an absorbing polarizer or an anti-reflective layer. In some embodiments, the aperture optical element 70 is a transparent element, such as a layer of glass or similar material. A virtual image 78 is formed, and the orientation of the virtual image is tilted with respect to the orientation of the display. The circuit block 1801 controls the display content and any active components, such as LC or electro-optical materials, that may be included in the first element 73 or the second element 74. The angle between the first element and the second element is θ, which is less than 45 degrees.

[0138] FIG. 18D shows an embodiment in which the elements of the field emission cavity 1 are curved. Light from the display 1 enters the cavity through a first element 73, which is a curved polarization-changing semi-reflector. The polarized light leaving this element is reflected by a curved second element 74, which is a reflective polarizer. The light is then reflected by the first element, rotated in polarization, then passes through the second element and through the aperture optic 70 to form a virtual image 78. The curvature of the element creates optical power, allowing the image to be magnified or reduced and its depth to be adjusted. In some embodiments, the curved element is a coating on a curved substrate. In some embodiments, the curved element is a freeform element, and the curvature or shape of the element is defined by a function.

[0139] In any of these embodiments, the angle between the first element 73 and the second element 74 may be less than 45 degrees. For example, it may be 1, 5, 10, 15, 20, 25, 30, 35, 40, or 44 degrees.

[0140] FIG. 18E illustrates an embodiment in which the field emission cavity includes an electro-optical (EO) material 1803 whose refractive index changes in response to an applied voltage. For example, when a first voltage is applied by the circuit block 1801, the EO material 1803 has a first value of refractive index, and when a second voltage is applied, it has a second value of refractive index. In some embodiments, the refractive index is not uniform but varies linearly across the element, so that when the applied voltage is changed, the refractive index changes, making the EO material 1803 an electrically controllable prism. For example, if the lateral refractive index is n(x)=n0+A(V)x, where x is the position and A(V) is a function of the applied voltage, the light is deflected in a direction that depends on A(V). Thus, light emitted by the display 6 passes through the first element 73, is reflected by the second element 74, is reflected by the first element, and is transmitted through the EO material 1803. It is deflected thereby and transmitted through the aperture optical element 70. The deflection may be in a first direction 1802A producing a first virtual image 78A, or in a second direction 1802B producing a second virtual image 78B depending on the state of the EO material 1803. In some embodiments, the display content is pre-compensated to account for any aberrations introduced by the EO material. That is, the display content may be distorted such that the combination of the distortion and any aberrations results in a sharp virtual image. In some embodiments, the function n(x) is not linear, but rather is a function that varies to minimize the aberrations. For example, the function may be a polynomial of degree higher than 1, a logarithmic function, an exponential function, etc.

[0141] 18F shows an embodiment in which light from the display 6 enters the field emission cavity 1 from the left. The light passes through the second element 74 and is reflected by the first element 73. In some embodiments, upon reflection, the polarization of the light is modified such that it is reflected by the second element and exits the system forming a shallow virtual image 78. The angle θ is less than 45 degrees.

[0142] In any of the above embodiments, a directional coating may cover the display panel to tilt the emitted light in a preferred direction before it enters the field emission cavity.

[0143] An advantage of these embodiments is that the virtual image is tilted at an angle that depends on the angle between the first element 73 and the second element 74. If we call the angle between them θ, then the tilt of the light accumulates by approximately 2θ after each round trip in the FEC. Thus, if θ is in the range of 1-30 degrees, the virtual image is tiled relative to the display by a range of 2-60 degrees after one round trip. If θ is in the range of 1-10 degrees, the virtual image is tiled relative to the display by a range of 3-30 degrees after two round trips.

[0144] Another advantage is the thinness of the display system. If the lateral direction is W ~ 30cm and the angle θ is 30 degrees, the thickness of the FEC is approximately Wtan θ, or 17cm. The shallower the angle, the thinner the display system. The thickness of the display may be 5cm, 10cm, 20cm, or 30cm. Furthermore, the virtual image size may be approximately the same as the display. In some embodiments, the virtual image is, for example, 1.2, 1.5, 2, 2.5, 3, 3.5, or 4 times larger.

[0145] 19A-19F show embodiments in which the above-mentioned display system is integrated into a vehicle. FIG. 19A is an embodiment in which a display system 1900 is integrated into a vehicle. The elements of the display system include the display itself, the field emission cavity, and any pre-cavity or post-cavity elements. In some embodiments, the display system includes an aperture optical element as an element. The display system generates a virtual image. In some embodiments, the display system 1900 is integrated into a vehicle part 1901A. In some embodiments, the display system 1900 is overlaid on a window and passes light from an external scene 1902 through it such that a virtual image 78 overlaps with the scene and creates an augmented reality (AR) environment. In some embodiments, the display system 1900 is connected to a surface of a vehicle part 1901B. The vehicle parts 1901A and 1901B may be, for example, but not limited to, a roof, a side panel, a door, a seat, a seat back, a window, or a mirror. Because the display system is thin (due to the acute angle between the first and second elements), it is substantially flush with the surface of the vehicle and any recessed cavity takes up little space to house it when not in use. A bulkier display would extrude more and would typically require a mechanism to fold it down when not in use or when it requires more space within the vehicle.

[0146] The inventive arrangement has limitations determined by the lateral size, distance to the observer, and viewing direction for viewing an obliquely oriented virtual image. In particular, an imaginary line extending from the observer's eye to the virtual image must pass through the aperture optic (or the geometric surface on which the aperture optic may be located). This is not the case, for example, for display systems with relatively small lateral dimensions that are located close to the observer.

[0147] 19B shows an embodiment in which the display system 1900 is set in a first position in a pocket 1905 or recessed area of ​​a vehicle part 1901. The display system is moved by a mechanical track 1904 into position, for example above a window 1903. Through the window an exterior scene 1902 is visible. Once the display system is in place, a see-through AR effect is created and a virtual image 78 is formed over the scene. In some embodiments, the display system creates augmented reality using see-through video, where a camera mounted on an exterior portion of the vehicle captures the exterior scene and displays the captured information on the display of the display system itself.

[0148] 19C shows an embodiment in which the display system 1900 is integrated into a vehicle component 1901, the roof of a car, where the display system is at least partially seen through. A mechanical track 1904 slides the display system into place from a recessed cavity in the roof. In some embodiments, the display system functions as a sunroof or window for the vehicle. In some embodiments, there is a separate sunroof 1905, where the display system and the sunroof are independently controlled by a first mechanical track 1904A and a second mechanical track 1904B.

[0149] FIG. 19D shows an embodiment in which a portion of the display system is mechanically adjustable relative to other components to modify the position and orientation of the virtual image. The display 6 is fixed to a vehicle part 1901, and light from the display is reflected by a first element 73, then reflected by a second element 74, then transmitted by the first element 73 through the aperture optics 70. The aperture optics and the first element are rotatable by a hinge 1906, which has the effect of shifting and rotating the virtual image 78. That is, the rotation changes the viewing experience during use of the display system. In some embodiments, the hinge is motorized. In some embodiments, the hinge is directly adjusted by the user. The hinge is an example of a movable joint, including a hinge, ball joint, or track, with the display system or its elements can move relative to the vehicle. The hinge includes at least a first part and a second part that move relative to each other. For example, the first part may be fixed to the vehicle part and the second part may be fixed to part or all of the display system.

[0150] 19E shows an embodiment in which the display system 1900 may reside in a recess in a vehicle part 1901. A pair of hinges 1906A, 1906B move the display system into position in front of a second vehicle part 1901A. A third hinge 1906C moves a panel 1907 to allow movement of the display system. The vehicle parts 1901A and 1901 may be parts of a seat in a vehicle. The circuit block 1801 may be used to control the movement of the hinges and the display system as time t progresses.

[0151] Figure 19F shows an embodiment that combines aspects of Figures 19A and 19D. The entire display system 1901 is connected to the vehicle part 1901 via a hinge 1906, which can be articulated to adjust the entire display system. The position of the resulting virtual image changes, but its position relative to the display system is fixed. In some embodiments, the hinge is instead an articulated arm or ball joint that allows the display system to rotate in multiple directions, i.e., to rotate it around different axes of rotation.

[0152] In any of the above embodiments, the mechanical integration features (levers, arms, hinges, and tracks) may be motorized and controllable via buttons integrated into the vehicle, or may be manually adjustable based on the viewer's actions.

[0153] 20A-20E are embodiments of the application of a display system in a vehicle. In FIG. 20A, a vehicle 76 houses two display systems 1900. These may be the display systems described above. Light leaves the display systems 1900 and is reflected across the vehicle by a mirror 2001. The reflected light is then reflected again by a side window 1903 and enters the eye of an observer 77. In some embodiments, the window is curved with a radius of curvature R, so that the window provides optical power and helps collimate the light, forming a virtual image 78 with a very far depth outside the vehicle.

[0154] A similar embodiment is shown in FIG. 20B. A vehicle 76 is integrated with its side display system 1900. In this embodiment, the display system can have further external components to complete the imager formation. A second element 74 reflects the light to a first element 73, which is a polarization-changing semi-reflector. The light is rotated 90 degrees and transmitted by a second reflector, which may be a reflective polarizer. The light is then viewed by a viewer 77 as a virtual image 78. Because the first elements are semi-reflective, they allow light from the external environment to pass through, so that the overlaid virtual image creates an AR environment.

[0155] An example of such an environment is shown in Figure 20C. A viewer 77 looks out a side window 1903 of a vehicle 76 and sees an external environment scene 1902. A portion 2002 of the scene overlaps with a virtual image 78, which may include annotations. In some embodiments, the annotations are generated at least in part by a GPS module or navigation system.

[0156] FIG. 20D shows an embodiment in which a display system 1900 is fixed to the roof 75 of a vehicle 76 to form a virtual image 78 above the vehicle. In some embodiments, the display system is partially transparent, allowing external light to pass through it, such that an external scene 1902 is simultaneously visible. In some embodiments, a GPS module 2003 may be electrically coupled to the display system to generate content that depends on the coordinates or orientation of the vehicle relative to the environment. In some embodiments, a simultaneous localization and mapping (SLAM) module is coupled to the display system. The SLAM module uses computational algorithms to map the vehicle's environment while simultaneously tracking the vehicle's position in the environment. Such algorithms include an extended Kalman filter or a particle filter. Such modules are particularly useful for autonomous vehicles.

[0157] FIG. 20E illustrates an embodiment similar to FIG. 16, where a display system 1900 is integrated to perform the function of a conventional mirror of a vehicle. In this embodiment, content from the external environment is captured by a camera 2004 fixed to the external part of the scene. In some vehicles, the camera is approximately in the position of a conventional side mirror and there is no side mirror. The camera can capture information about the environment to the side of the vehicle and display it on a display system 1900 fixed inside the vehicle 76, for example on an interior door 2005. In some embodiments, the camera captures information about the rear of the vehicle and displays it on a display system 1900 fixed to the vehicle by an arm 2006, for example instead of a conventional rearview mirror. The advantage of this scenario, compared to a conventional "digital mirror" which is simply a display panel replacing the mirror, is that the depth associated with objects in the external environment can be preserved by the depth of the virtual image of the display system.

[0158] Although the present invention has been described in relation to its preferred embodiments, it should be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention as hereinafter claimed.

[0159] Various aspects may be described algorithmically herein. Although exemplary algorithms may be provided, the desired functionality may be implemented in any suitable manner. One skilled in the art may implement such functionality or algorithms, for example, in hardware, software, or a combination of hardware and software. A module (e.g., a "GPS module," a "SLAM module") may comprise hardware and / or software to implement the disclosed functionality or algorithms. For example, in some embodiments, an algorithm may be implemented through a module having one or more processors executing computer code stored on one or more non-transitory computer-readable storage media. In some embodiments, functionality is implemented at least in part through a module having dedicated hardware (e.g., ASIC, FPGA). In some embodiments, modules may share components. For example, a first functional module and a second functional module may both utilize a common processor (e.g., through time sharing or multithreading) or have computer executable code stored on a common computer storage medium (e.g., in different memory locations).

[0160] In some cases, a module may be identified as a hardware module or a software module. A hardware module includes or shares hardware for implementing the functionality of the module. A hardware module may include software, i.e., may include a software module. A software module comprises information that may be stored, for example, on a non-transitory computer-readable storage medium. In some embodiments, the information may comprise instructions executable by one or more processors. In some embodiments, the information may be used at least in part to configure hardware such as an FPGA. In some embodiments, an algorithm may be recorded as a software module. A capability may be implemented, for example, by reading a software module from a storage medium and executing it on one or more processors, or by reading a software module from a storage medium and using the information to configure hardware.

[0161] As used herein, "machine-readable medium," "computer-readable medium," and similar terms are used to refer to a non-transitory medium, volatile or non-volatile, that stores data and / or instructions that cause a machine to operate in a specific manner. Common forms of machine-readable medium include, for example, hard disks, solid-state drives, magnetic tapes, or any other magnetic data storage medium, optical disks, or any other optical data storage medium, any physical medium with a pattern of holes, RAM, PROM, EPROM, FLASH-EPROM, NVRAM, any other memory chip or cartridge, and networked versions thereof.

[0162] These and various other forms of computer readable media may be involved in carrying one or more sequences of one or more instructions to a processing device for execution. Such instructions embodied on the media may be referred to as "instructions" or "code," and the instructions may be grouped together in the formation of a computer program or other grouping. When executed, such instructions may enable the processing device to perform the features or functions of the present application as discussed herein.

[0163] As used herein, a "processing device" may be implemented as a single processor that performs processing operations, or a combination of special-purpose and / or general-purpose processors that perform processing operations. A processing device may include a CPU, GPU, APU, DSP, FPGA, ASIC, SOC, and / or other processing circuitry.

[0164] Various embodiments described herein are described with reference to exemplary block diagrams, flow charts, and other diagrams. As will be apparent to one of ordinary skill in the art after reading this specification, the illustrated embodiments and their various alternatives can be implemented without being limited to the illustrated examples. For example, the block diagrams and their accompanying description should not be construed as mandating a particular architecture or configuration.

[0165] Each of the processes, methods, and algorithms described in the previous sections may be embodied in code components executed by one or more computer systems or computer processors with computer hardware, and may be fully or partially automated. The methods and algorithms may be implemented partially or entirely in application-specific circuits. The various features and processes described above may be used independently of each other, or may be combined in some ways. Different combinations and subcombinations are intended to fall within the scope of the present disclosure, and some method or process blocks may be omitted in some implementations. Furthermore, unless the context dictates otherwise, the methods and processes described herein are not limited to any particular sequence, and the blocks or states associated therewith may be performed in other appropriate sequences, or may be performed in parallel, or may be performed in some other manner. Blocks or states may be added to or removed from the disclosed exemplary embodiments. The performance of a particular operation or process may not only reside within a single machine, but may also be distributed among computer systems or computer processors spread across several computing resources.

[0166] As used herein, the term "or" may be construed in an inclusive or exclusive sense. Additionally, describing a resource, operation, or structure in the singular should not be construed as excluding the plural. Unless otherwise stated or understood otherwise within the context as used, conditional language such as "can," "could," "may," or "potential," among others, is intended to generally convey that a particular embodiment includes, but other embodiments do not include, certain features, elements, and / or steps.

[0167] Terms and phrases used herein, and variations thereof, unless otherwise expressly stated, should be construed as open ended rather than limiting. The purpose of words such as "conventional," "conventional," "usual," "standard," "known," and words of similar meaning should not be construed as limiting the items described during a given period or to items available as of a given time, but instead should be construed to encompass conventional, conventional, ordinary, or standard technology that may be available or known at any time now or in the future. The presence of broadening phrases such as "one or more," "at least," "not limited to," or other similar phrases should not be construed to imply that a narrower case is intended or required in the absence of such broadening phrase.

Claims

1. 1. A display system comprising: a light-emitting display panel; a field emission cavity that directs the light from the display panel along a path to produce a virtual image oriented at an oblique angle to the display panel; Equipped with The field emission cavity comprises: a polarization-changing reflector disposed along said path for converting said light from a first polarization to a second polarization; a polarization dependent reflector positioned along the path after the polarization changing reflector at an angle of less than 45 degrees to the polarization changing reflector, the polarization dependent reflector reflecting light of the second polarization and transmitting light of the first polarization; an aperture optic for transmitting the light away from the field emission cavity; having Display system.

2. The display system of claim 1 further comprising a vehicle having said display panel and said field emission cavity mounted therein.

3. 3. The display system of claim 2, wherein the depth of the virtual image is outside the vehicle.

4. The display system of claim 2 , further comprising a camera for capturing information about an external environment, said virtual image being based on said information.

5. The display system of claim 1 , wherein the polarization-changing reflector comprises a waveplate and a reflector.

6. 10. The display system of claim 1, wherein the aperture optics comprises an absorptive polarizer and an anti-reflective layer.

7. The display system of claim 1 , wherein said display panel and said field emission cavity are mounted to a roof of a vehicle.

8. The display system of claim 1 , wherein the display panel and the field emission cavity are mounted to a vehicle component selected from the group consisting of a door, a seat, a floor, and a side panel.

9. The display system of claim 1 further comprising a directional coating disposed along said path.

10. 10. The display system of claim 1, wherein the oblique angle between the virtual image and the display panel is a first oblique angle, and the display panel is oriented at a second oblique angle relative to the polarization-changing reflector.

11. The display system of claim 1 , wherein a thickness of the display system is less than a lateral dimension of the display system.

12. The display system of claim 1 , further comprising a Global Positioning System (GPS) module for modifying content of the virtual image.

13. The display system of claim 1 , further comprising a simultaneous localization and mapping (SLAM) module for modifying the content of the virtual image.

14. 1. A display system comprising: a light-emitting display panel; a field emission cavity that directs the light from the display panel along a path to produce a virtual image oriented at an oblique angle relative to the display panel; Equipped with The field emission cavity comprises: a polarization-changing semi-reflector positioned to transmit and convert said light from a first polarization to a second polarization; a polarization dependent reflector positioned along said path after said polarization changing semi-reflector at an angle of less than 45 degrees relative to said polarization changing semi-reflector; an aperture optic for transmitting the light away from the field emission cavity; having Display system.

15. The display system of claim 14 further comprising a vehicle having said display panel and said field emission cavity mounted therein.

16. 16. The display system of claim 15, wherein the depth of the virtual image is outside the vehicle.

17. 17. The display system of claim 16, wherein the field emission cavity further comprises a window of the vehicle that reflects the light to generate the virtual image, the virtual image forming an augmented reality view of an external environment.

18. 16. The display system of claim 15, further comprising a camera that captures information about an external environment, said display panel and said field emission cavity being mounted within said vehicle, and said virtual image being based on said information.

19. 16. The display system of claim 15, further comprising a movable joint having a first portion and a second portion, the first portion and the second portion moving relative to one another with movement of the movable joint, the first portion being attached to the vehicle, and at least one of the field emission cavity, the display panel, and the aperture optical element being attached to the second portion.

20. 15. The display system of claim 14, wherein the polarization-changing semi-reflector comprises a first wave plate, a beam splitter, and a second wave plate.

21. The display system of claim 14 , wherein the polarization-changing semi-reflector and the display panel form an oblique angle.

22. 15. The display system of claim 14, wherein the aperture optics comprises an absorptive polarizer and an anti-reflective layer.

23. The display system of claim 14 , wherein the display panel and the field emission cavity are mounted to a roof of a vehicle.

24. 15. The display system of claim 14, wherein said display panel and said field emission cavity are mounted to a vehicle component selected from the group consisting of a door, a seat, a floor, a side panel, and a window.

25. The display system of claim 14 further comprising a directional coating disposed along the path.

26. The display system of claim 14 , wherein the display is oriented at an oblique angle to the polarization-changing reflector.

27. The display system of claim 14 , wherein a thickness of the display system is less than a lateral dimension of the display system.

28. The display system of claim 14 , further comprising a Global Positioning System (GPS) module for modifying the content of the virtual image.

29. 15. The display system of claim 14, further comprising a simultaneous localization and mapping (SLAM) module for modifying the content of the virtual image.

30. The display system of claim 14 wherein the polarization-changing semi-reflector is curved.

31. 31. The display system of claim 30, wherein the polarization dependent reflector is curved.

32. The display system of claim 14 , wherein the polarization dependent reflector is a reflective polarizer.

33. An in-vehicle display system, a light-emitting display panel; a field emission cavity for directing the light from the display panel to generate a virtual image, A plurality of polarization dependent semi-reflectors; Aperture optics; a field emission cavity having a vehicle having mounted thereon said display panel and said field emission cavity; Equipped with The depth of the virtual image is outside the vehicle. In-vehicle display system.

34. 34. The in-vehicle display system of claim 33, wherein the virtual image is formed after being reflected by a surface of the vehicle, and the virtual image is located beyond a side of the vehicle.

35. 35. The in-vehicle display system of claim 34, wherein a Global Positioning System (GPS) or Simultaneous Locating and Mapping (SLAM) module is used to modify the content of the virtual image.

36. 34. The in-vehicle display system of claim 33, wherein a Global Positioning System (GPS) or Simultaneous Locating and Mapping (SLAM) module is used to modify the content of the virtual image.

37. 34. The in-vehicle display system of claim 33, wherein the field emission cavity further comprises a polarization dependent reflector and a polarization changing semi-reflector.

38. 34. The in-vehicle display system of claim 33, further comprising a camera for capturing information about an external environment, said display panel and said field emission cavity being mounted to a mirror of said vehicle, and said virtual image being based on said information.

39. 34. The in-vehicle display system of claim 33, wherein the light makes multiple round trips within the field emission cavity.

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