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

Abstract

This system provides a way to create compact light field displays across various optical depths. [Solution] A display system and method for generating a virtual image or light field image includes, in some embodiments, a display and a field emission cavity. The field emission cavity modularizes the optical depth of the virtual image. In some embodiments, the display system is integrated into a part of a vehicle. The virtual image can be reflected by the part of the vehicle to generate an augmented reality (AR) environment for passengers.

Description

Technical Field

[0001] This application claims the benefit / priority of Application No. 18 / 066,844, entitled "System and Method for Generating Compact Light-Field Displays through Varying Optical Depths," filed on December 15, 2022. The entire content of the same application is incorporated herein by reference.

[0002] The present invention generally relates to light field displays. More specifically, the present invention is a system for creating compact light field displays through varying optical depths.

Background Art

[0003] In today's society, advances in electronics and microfabrication are driving increased demand for more immersive light field and / or automated stereoscopic (3D) displays. Unlike stereoscopic 3D, light field displays manipulate wavefronts to generate depth perception at the monocular level. This can eliminate accommodation-convergence mismatch and reduce stress on the user's eyes. Breakthroughs are underway to achieve a more realistic light field experience, which can be described by four main methods for creating such an experience, each method having its own weaknesses and advantages: ultra-multifocal, computational, multifocal, and holographic. The ultra-multifocal method provides a light field in a very compact form but is limited to a very small field of view zone and low resolution. The computational method increases resolution but produces haze and temporal flicker artifacts. The holographic method may suffer from color inhomogeneity and fringing or specular artifacts. The multifocal method is not scalable but can produce clean images. Also, devices using the multifocal method can be bulky. However, the following problems are common to all current methods of light field displays: wide bandwidth requirements; reliance on expensive and / or advanced components that are not easily mass-produced, such as adjustable lenses; insufficient color uniformity, small field of view or field zone, low brightness, haze and diffraction artifacts, limited depth range; and the occasional 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 full-class optical method that, in some embodiments, uses a set of reflectors placed within 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 within the cavity to adapt to a certain optical depth before it leaves the exit pupil of the cavity, while simultaneously solving the aforementioned problems associated with other methods of light field displays.

[0004] The object of the present invention is to provide users with a device that is a compact system for creating light field displays at or through various optical depths. The present invention is intended to provide users with a device that addresses the aforementioned problems associated with current methods of light field displays. The present invention is intended to provide users with a device that is less expensive and easier to manufacture at or for commercial and / or industrial levels. The present invention is intended to provide users with a device that reduces artifacts without reducing the clarity of light field displays. The present invention is intended to provide users with a device that enables users to generate content for light field displays more easily than with conventional stereoscopic displays. The present invention is intended to provide users with a device that does not require additional accessories or specialized components (e.g., special glasses or rendering engines) used by the user to view content on a light field display. The present invention is intended to provide users with a device that can reduce the optical path difference to each focal plane of a light field display and minimize light loss from polarization. The present invention is intended to provide users with a device that can change the focal plane of a display without any mechanical movement. [Overview of the Initiative]

[0005] The present invention is a system for creating a compact light field display through various optical depths. The present invention mainly includes a housing. The housing includes a plurality of panels in various arrangements, which enable the present invention to produce light field displays of various degrees or ranges. The present invention also includes a relay panel. The present invention includes a cover case on top of the housing.

[0006] Achieving accurate light field displays typically requires sophisticated optical structures using expensive light sources and spatial modulators, such as laser scanners, tunable lenses, liquid crystal on silicon (LCoS) reflectors, or digital micromirror devices (DMDs). Therefore, these existing methods do not provide true optical depth. This means there is wavefront inaccuracy in the form of diffraction color inaccuracies, speckle, or haze. A certain class of display systems and methods revolves around the concept of field-emission (FE) cavities. These cavities prepare light to provide true optical depth without wavefront distortion, and therefore the images provided by such systems are as accurate as those from conventional 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 enhanced (transparent) devices. The system can also be conveniently packaged in a small form factor well-suited for desktop applications. Since the cavities supply regular two-dimensional (2D) images and optically couple them to a 3D light field, there is no need for a complex rendering engine. This method is also scalable to large-scale displays for commercial use. [Brief explanation of the drawing]

[0007] The patent application file includes at least one drawing made in color. A copy of this patent or the publication of the patent application accompanied by the color drawing will be provided by the Patent Office upon request and payment of the required fees.

[0008] The following description is intended to be non-limiting and illustrative, with reference to the accompanying drawings, and provides further details, for example, of embodiments of the disclosed apparatus, methods, and systems. [Figure 1]A light field display based on a three-layer field emission cavity is shown, along with a non-limiting example of a 3D model of a three-layer light field display prototype, with a front view on the left, a rear top view in the center, and a front side view on the right. [Figure 2] A generalized block diagram of the cavity-based light field system in this disclosure is shown, and a block diagram of the FE cavity-based light field display system is shown, in which the cavity generates light from multiple focal planes, supplies it to a relay mechanism, and then projects it to the outside. [Figure 3A] An example of a Class I FE cavity with a primary exit pupil is illustrated. The display is arranged in one dimension or one axis (either vertical or horizontal), and the light from each layer bounces off each reflector only once. This means there is no round trip or loop that the light travels before leaving the cavity. Non-limiting examples of different designs under the Class I FE cavity category, from simple layers to more complex multilayers, are shown. [Figure 3B] An example of a Class I FE cavity with a primary exit pupil is illustrated. The display is arranged in one dimension or one axis (either vertical or horizontal), and the light from each layer bounces off each reflector only once. This means there is no round trip or loop that the light travels before leaving the cavity. Non-limiting examples of different designs under the Class I FE cavity category, from simple layers to more complex multilayers, are shown. [Figure 3C] An example of a Class I FE cavity with a primary exit pupil is illustrated. The display is arranged in one dimension or one axis (either vertical or horizontal), and the light from each layer bounces off each reflector only once. This means there is no round trip or loop that the light travels before leaving the cavity. Non-limiting examples of different designs under the Class I FE cavity category, from simple layers to more complex multilayers, are shown. [Figure 4]An example of a Class II FE cavity with a primary exit pupil is shown, where Class II displays can be arranged in two dimensions (both horizontal and vertical) to form the cavity. The term "primary" refers to the fact that light bounces off each mirror or reflector one or less times. An example of a more complex Class II FE cavity is shown, demonstrating 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 represent the light beams exiting the pupil of the cavity. [Figure 5] Examples of Class I and Class II FE cavities with primary and secondary exit pupils designed to reduce optical path differences to each focal plane and minimize optical loss are shown; "secondary" means that light can bounce off the reflector up to two times. Examples of FE cavities with higher-order exit pupils designed to reduce optical path differences to each focal plane and minimize optical loss by using polarization are also shown. [Figure 6] An example of an FE cavity having a dynamically translating (mechanically translating) component used to adjust or sweep the focal plane throughout a range of depths is shown. [Figure 7] Examples of FE cavities with switchable mirror elements and switchable diffusers for changing the depth of focus of the emitted light are shown. An example of a display cavity that changes the display focal plane without overall mechanical movement is shown using switchable mirrors (profiles 22 and 23 in Figure 6) and a switchable diffuser (profile 24 in Figure 6). [Figure 8] An example is shown of using a switchable liquid crystal layer to switch the path that light takes within different sections of the FE cavity. An example is shown of an FE cavity that changes the display focal plane without any mechanical movement using a switchable liquid crystal layer. [Figure 9]Examples of wedge-type (or angled) FE cavities used to generate multiple focal planes are shown. In these cavities, the display panel normal vectors may form angles with respect to each other that are not multiples of 90 degrees. Examples of small Class I and II wedge cavities used to generate multiple focal planes in a smaller form factor are also shown. [Figure 10] Examples are shown where one or all of the depth is shifted using a slab or prism with a higher refractive index. It also shows how prism films can improve the brightness of the focal plane. Examples are shown of passively adjusting or improving the depth and brightness of the focal plane using materials with different refractive indices within the cavity volume or prism film. [Figure 11] This shows examples of relay systems used to relay light from a cavity to the outside world. The display may be used as a display standing at a distance or very close to the head, such as on a desktop. Relays can be completely transparent or opaque, curved or flat, and consist of one piece or multiple switching sections. This shows how the output of a display cavity can be relayed to an audience as part of an entertainment system or a magnified monitor. The left column shows entertainment system modalities, and the right column shows a magnified near-head display modalities. [Figure 12] An example of a compressed FE cavity based on switchable mirrors is shown. The cavity thickness (L) can be reduced by sequentially turning the reflectors on and off. This demonstrates how a compressed architecture with switchable mirrors in a Class I FE cavity can compress the system size. [Figure 13] This 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 emanating from the green reflector at the top. [Figure 14A]This describes an embodiment in which the aperture optics are positioned in the cavity exit pupil of the field emission cavity. [Figure 14B] This describes an embodiment in which the aperture optics are positioned in the enclosure exit pupil of the system enclosure. [Figure 15] This invention illustrates an embodiment of a field emission cavity in which the elements are segmented and configured as a light pipe that generates multiple depths or images. [Figure 16] This embodiment of the present invention shows a field emission cavity that is optically connected to a mirror, which generates a virtual image at the same depth as or closer to the observer's reflection. [Figure 17] This shows an embodiment of the present invention in which the field discharge cavity is integrated into the roof of the vehicle. [Figure 18A] Figure 17 shows various embodiments of the display system, which utilize polarization-dependent reflectors or semi-reflectors. [Figure 18B] Figure 17 shows various embodiments of the display system, which utilize polarization-dependent reflectors or semi-reflectors. [Figure 18C] Figure 17 shows various embodiments of the display system, which utilize polarization-dependent reflectors or semi-reflectors. [Figure 18D] Figure 17 shows various embodiments of the display system, which utilize polarization-dependent reflectors or semi-reflectors. [Figure 18E] Figure 17 shows various embodiments of the display system, which utilize polarization-dependent reflectors or semi-reflectors. [Figure 18F] Figure 17 shows various embodiments of the display system, which utilize polarization-dependent reflectors or semi-reflectors. [Figure 19A] Exemplary methods by which a display system may be integrated into a vehicle include mechanically articulated or electrically coupled connections. [Figure 19B]An exemplary method is shown in which a display system including a mechanically articulated or electrically powered coupling can be integrated into a vehicle interior. [Figure 19C] An exemplary method is shown in which a display system including a mechanically articulated or electrically powered coupling can be integrated into a vehicle interior. [Figure 19D] An exemplary method is shown in which a display system including a mechanically articulated or electrically powered coupling can be integrated into a vehicle interior. [Figure 19E] An exemplary method is shown in which a display system including a mechanically articulated or electrically powered coupling can be integrated into a vehicle interior. [Figure 19F] An exemplary method is shown in which a display system including a mechanically articulated or electrically powered coupling can be integrated into a vehicle interior. [Figure 20A] Exemplary applications of the disclosed display system and field emission cavities are shown. [Figure 20B] Exemplary applications of the disclosed display system and field emission cavities are shown. [Figure 20C] Exemplary applications of the disclosed display system and field emission cavities are shown. [Figure 20D] Exemplary applications of the disclosed display system and field emission cavities are shown. [Figure 20E] Exemplary applications of the disclosed display system and field emission cavities are shown.

Best Mode for Carrying Out the Invention

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

[0010] In conventional binocular or stereoscopic vision, the display system provides two offset images separately to the viewer's left and right eyes. These two-dimensional images are then combined in the observer's brain, along with the accommodation of the eye's lens, to give the viewer a perception of 3D depth in front of them. If the true optical depth (wavefront curvature) does not match the parallax provided by the stereoscopic image, the viewer experiences a slightly uncomfortable inaccuracy. This is because the lens of their eye tells the brain that the image is at a certain distance, while the parallax tells the brain that it is not. This is known as accommodation-convergence mismatch. Light field display systems vary the wavefront to provide both parallax and accommodation cues. Conventional 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 the realism and manufacturability of perceived content, 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 depths of focus, which is then relayed to the outside world. This approach does not require adjustable lenses or a powerful computational rendering engine; it does not necessarily rely on free-form optics, can be manufactured cost-effectively, and provides a light field experience to any number of users within a large field of view zone.

[0012] general purpose The present invention provides a mass-producible method for multi-layer light field experiences with image accuracy comparable to high-quality displays. The objective of the invention is to realize a compact, practical transparent or opaque light field display that provides true optical depth without being plagued by accommodation-convergence competition. Such displays have wide-ranging utility in various situations, which will be further detailed below. Light fields can be used as entertainment displays for commercial applications, or in industrial use cases such as navigation or biomedical applications. In near-head use cases, the invention provides virtual depth or optical space that, despite having small pupils, can appear like a virtual window and provide a sense of scale. For example, the invention can enlarge a 13-inch exit pupil located 10 inches from the head to appear as a 60-inch monitor located 3 meters 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 Figures 1 to 13. The system enclosure 5 is used to house the 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 plays a role in modifying 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 the modified light field display is then 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 enables the generation of at least one light field display 6 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 transmit the modified light field display from the cavity exit pupil 2 to the enclosure exit pupil 4 of the system enclosure 5, and thus 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-emitting cavity 1 for a prototype model of the present invention. In Figure 1, the cavity exit pupil 2 is also shown by a dotted rectangular frame. In this case, the relay mechanism 3 is a simple mirror or a switchable mirror that relays the cavity exit pupil 2 to the enclosure exit pupil 4. The enclosure exit pupil 4 also allows the light emitting from this pupil to reach the user directly without further operation. This enclosure exit pupil 4 is shown in Figure 1 by a dashed rectangular frame.

[0015] Technical explanation The disclosed apparatus, methods, and systems describe various methods, systems, components, and techniques that enable the display of digital content in two or more focal planes and contribute 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 emission cavity 1 and relaying this content to the user's eyes, as shown in Figure 2.

[0016] Firstly, digital content is generated within the field emission cavity 1 at one or more depths. This can be done in various ways, the details of which are described in the section titled "Design of the Field Emission Cavity." Next, a relay mechanism 3 is used to enable the user to view the digital content in different modalities, the details of which are described in the section titled "Relay Mechanism and Application Modalities."

[0017] Furthermore, the technologies described herein can be used not only in large-scale displays such as desktop monitors, television sets, and head-up displays, but also in new modalities of near-eye displays. Details of this application extension are described in the section titled "Relay Mechanisms 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 titled "Compression Design." Details of non-limiting examples of practical prototypes are described in the section titled "Prototype Models."

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

[0019] Design of a field discharge cavity To provide true optical depth to different layers of the light field, an optical mechanism is required to prepare or manipulate the curvature of the wavefront of light, which is true to that depth or compensates for that depth. Various embodiments of the field emission cavity 1 illustrated in Figures 3-13 are cavities or voids comprising 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 planar 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 beams of light having diverging vertices at different depths from the cavity emission pupil 2. These vertices may be from different displays at different depths within the field emission cavity 1, or from a single display panel 6 along the entire field emission cavity 1. The cavity exit pupil 2 delivers light to the relay mechanism 3, resulting in different or the same reference vertex (depending on the type of relay) of divergence of different focal planes presented to the user. The relay mechanism 3 may be a simple flat surface, a free-form curved surface as further described herein, a geometric or diffractive waveguide, or any other suitable relay means. The relay mechanism 3 may be translucent, opaque, or have adjustable transparency (e.g., a switchable mirror).

[0020] Since theoretically there are infinitely many types of field-emitting cavities, determining the class of field-emitting cavity 1 is based on the dimensions of the display configuration. If all of the display panels 6 are aligned along a single axis (e.g., the y-axis), field-emitting cavity 1 is defined as class I. More specifically, the display panels 6 are arranged along a single axis, and the single axis 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, field-emitting cavity 1 is class II. More specifically, multiple display panels 6 are arranged along a pair of axes, the pair of axes 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 a beam of light from any pixel of the display panel 6 is reflected before it exits the cavity exit pupil 2. Any field-ejecting cavity 1 having at least one display panel 6 positioned at an angle 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 with respect to the cavity exit pupil 2.

[0021] The following descriptions and drawings of Figures 3 to 13 provide non-limiting examples of a Class I field-emitting cavity, which may be used to generate digital content at multiple depths of focus using a single display panel 6 or multiple display panels 6 arranged in parallel. In all of these configurations, the display panel 6 may be a variety of display technologies, such as OLED, LCD, LED, AMOLED, or any display technology or projection screen that provides 2D images. In non-limiting examples of these concepts, the display panel 6 may be replaced with an LCoS (Liquid crystal on silicon) spatial light modulator illuminated by continuous RGB light, or a DMD (Digital Mirror Device) 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 non-limiting examples and configurations shown in Figures 3 to 9, the reflector may be a polarization-dependent reflector, a translucent reflector, a thin-layer pellicle reflector, a beam splitter cube, or other suitable reflector. In all these configurations, light from different parts of the display panel 6 or different panels 6 may be polarized to increase the output optical efficiency of the light emission cavity 1. More specific examples are given in the drawings throughout this disclosure.

[0023] Figures 3A, 3B, and 3C show some non-limiting examples of designs for Class I field emission cavities 1. Generally, the optical tuning mechanism 7 may comprise at least one mirror 8 and at least one beam splitter plate 9. As can be seen from the section of Figure 3, a particular cavity arrangement may be configured to reflect the optical path using the mirror 8, a particular cavity arrangement may be configured to reflect the optical path using the beam splitter plate 9, to pass the optical path through the beam splitter plate 9, or a combination thereof.

[0024] Section 5 of Figure 3A shows a Class I embodiment of a field-emitting cavity 1 having a single display panel 6 at the bottom, producing only a single depth (included for theoretical support). Light exits directly from the cavity exit pupil 2 without bouncing off any reflectors or other optical surfaces. This is the zero-order cavity exit pupil 2. Orange arrows indicate the beam of light exiting from the dashed line, which is the cavity exit pupil 6, in all figures of this disclosure. In all figures, only light exiting from the light-emitting cavity 1 is indicated by red or blue arrows. Wasted light is not shown in these figures for simplicity. Also, for any beam splitter plate 9, the reflectance percentage can be selected to maximize the luminance uniformity of all layers. This does not alter the architecture of the design, and therefore the reflectance percentage is not specified throughout this disclosure. For simplicity, the reflectance percentage can be assumed to be 50% for all designs.

[0025] Section 6 of Figure 3A shows an embodiment of a Class I field emission cavity 1 with a single display panel 6 on the right wall that simultaneously generates digital content at two different depths. By incorporating a beam splitter plate 9 (half-mirror sheet) and a mirror 8, light is combined and redirected outward from the cavity exit pupil 2. Light from the top of the display panel 6 is reflected by 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 is reflected by the beam splitter plate 9, and half of its intensity is directed towards the cavity exit pupil 2. Thus, this is a Class I first-order field emission cavity 1, where the intensity at each focal plane is half of the original intensity of the display panel 6. In some examples of this type of field emission cavity 1, one or more of the reflectors may be shifted up or down to change the desired depth to which the light is output to the cavity exit pupil 2.

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

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

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

[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 simultaneously at multiple depths.

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

[0031] Figure 4 shows a non-limiting example of the design of a Class II field-emitting cavity 1 with a cavity-exit pupil 2.

[0032] Section 12 of Figure 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 two display panels 6 have the advantage of being able to generate digital content simultaneously at two similar depths. The depth separation between the two focal planes can be easily adjusted by adjusting the position of one of the display panels 6.

[0033] Section 13 of Figure 4 shows a simple Class II embodiment of a field-emitting cavity 1, which has four display panels 6 that are combined to generate digital content simultaneously at four different depths.

[0034] Section 14 of Figure 4 shows the final extension of Section 13 of Figure 4, which generates digital content simultaneously at multiple different depths.

[0035] Section 15 of Figure 4 shows an embodiment of a simple Class II field-emitting cavity 1, which has four central display panels 6 that are combined to generate digital content simultaneously at four different depths.

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

[0037] Figure 5 shows examples of Class I and Class II field emission cavities 1 having higher-order exit pupils 2. These non-limiting embodiments demonstrate how polarization and multiple reflections from the same surface can generate more compact cavities with a greater number of output focal planes. Generally, the optical tuning mechanism 7 may 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 section of Figure 5, a particular cavity configuration may be configured to reflect the optical path with a first polarization using the polarization-dependent beam splitter plate 10, to pass the optical path through the polarization-dependent beam splitter plate 10 with a second polarization, or a combination of these, where the first polarization is opposite to the second polarization. A particular cavity configuration may further configure, using a combination of the quarter-wave plate 11 and a mirror 8, to switch the optical path from a first linear polarization to a second linear polarization, where the first linear polarization is perpendicular to the second linear polarization.

[0038] Section 17 of Figure 5 shows an embodiment of a Class II field-emitting cavity 1 comprising 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 completely reflects one polarized beam and completely transmits the other perpendicular polarized beam. The two display panels 6 have the advantage of being able to generate digital content simultaneously at two similar depths. 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 by utilizing the polarization of the display panels 6 in conjunction with the PDBS plate 10, optical loss is minimized.

[0039] Section 18 of Figure 5 shows an embodiment of a second-order Class II field emission cavity 1 that uses a PDBS plate 10 and a waveplate 11 to efficiently generate two different focal planes (image depths). In this embodiment, light from the vertical display panel 6 has horizontal polarization and strikes the PDBS plate 10, which reflects only horizontally polarized light. Thus, this light (circularly shown by the red arrow) travels upward and passes through the quarter-waveplate 11 (shown in purple). This quarter-waveplate 11 converts the horizontal polarization to clockwise circular polarization, which then strikes the half-mirror at the top of the horizontal display (shown in blue) and is reflected back with counterclockwise polarization. The quarter-waveplate 11 converts its counterclockwise circular polarization to vertical linear polarization (circularly shown by the red arrow). This light passes through the PDBS plate 10 and exits through the cavity exit pupil 2. Light from the horizontal display panel 6 has counterclockwise polarization and, upon passing through the quarter-wave plate 11, is converted to vertical polarization before passing through the PBDS plate 10. This method of using the quarter-wave plate 11 along the reflective surface 8 can be widely used in many other configurations for the field emission cavity 1, as shown in Figures 5 to 10. The function is identical to that described for this configuration, where the wave plate 11, together with the reflective surface 8, reflects and rotates the polarization by 90 degrees. Therefore, when light with horizontal polarization passes through these layers, the light is reflected back with vertical polarization, and vice versa. When vertical polarization is reflected from this structure, the light is reflected with horizontal polarization.

[0040] Section 19 of Figure 5 shows an embodiment of a second-order Class II field emission cavity 1, which includes a single display panel 6 combined with a series of beam splitter plates 9 and mirrors 8. Using a single display panel 6 has the advantage of being able to generate digital content simultaneously at two similar depths. The depth separation between the two focal planes can be adjusted by adjusting the position of the central beam splitter plate 9. This embodiment is a Class I field emission cavity 1 because the display panel 6 exists in only one dimension, and this embodiment has a second-order cavity exit pupil 2, as light from the lower portion of the display panel 6 is reflected once by the lower beam splitter plate 9 and then reflected again by the horizontal half-mirror (it also passes through the lower beam splitter plate 9 before exiting). Higher-order field emission cavities 1 can offer more flexibility in terms of design and form factor, but tend to have lower light efficiency.

[0041] Section 20 of Figure 5 shows an embodiment of a secondary 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 reflected from the reflector 8 to the cavity exit pupil 2. Light from the right display panel 6 is x-polarized, which is reflected downward, passes through the waveplate 11, strikes the bottom mirror 8, passes through the waveplate 11 again, shifts its 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-emitting cavity 1 configured such that light from the right display panel 6 is x-polarized, resulting in the light being reflected from the PDBS plate 10. Light from the lower display panel 6 has rotated polarization as it passes through the waveplate 11 and through the oblique PDBS plate 10 to the cavity exit pupil 2. Light from the right display panel 6 is reflected downward by the PDBS plate 10, rotates the polarization of the waveplate 11, is partially reflected by the bottom beam splitter plate 9, and then passes through the oblique PDBS plate 10 to the cavity exit pupil 2.

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

[0044] Section 22 of Figure 6 shows an embodiment of a Class I field emission cavity 1 comprising 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 adjustable display panel 6, and the position of the display panel 6 can be adjusted to correspond to the user's congestion depth and can be continuously swept while continuously updating the displayed digital content (to generate a light field), or, if the digital content is at a known depth, can be simply set to match the perceived depth of the digital content. This mechanical motion can be combined with a curved relay to increase the optical range of depth variations, which is usually necessary since mechanical translation with a wide range is usually impractical. Various means such as mechanical stages, piezoelectric transducers, or voice coils can be considered for these mechanical translations.

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

[0046] Section 24 of Figure 6 shows an extension of Section 23 of Figure 6, including a movable mirror 8 to enable faster movement of the dynamically adjustable focal plane. Digital content is generated simultaneously at two different depths, one of which is dynamically adjustable. Faster movement can be achieved by using a higher-order field emission cavity 1, but generally, the speed of depth movement is slower when mechanical motion is used. The translational speed is typically a direct function of the order. An example in Section 24 of Figure 6 shows a doubling of the speed of adjustment or movement because light strikes the right mirror 8 and returns to a delta deformation of the mirror 8's position, or the display panel 6 is doubling through the round trip of light. 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] Referring to Figure 7, the optical tuning mechanism 7 may further comprise a plurality of switchable mirrors 13 that communicate serially with each other and are arranged offset from each other. As can be seen from the section of Figure 7, a particular cavity arrangement may be configured 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 that particular mirror.

[0048] Section 25 of Figure 7 illustrates an embodiment of a field emission cavity 1 that generates digital content at multiple depths, each determined by the activated switchable mirror 13 (the one that reflects light), utilizing a stack of polarized display panels 6 and polarization-dependent switchable liquid crystal mirrors 13. Many techniques exist to provide functionality for the switchable mirrors 13, and a non-limiting example of a switchable mirror 13 is a liquid crystal cell (LCC) positioned on top of a polarization-dependent reflector. If the incident light has the same polarization axis as the reflective surface, the light is reflected from the switchable mirror 13. When the LCC is turned on, so that the LCC cross-polarizes the incident light with the reflecting polarizer, the light passes through and the mirror becomes transparent. Other techniques for the switchable mirrors 13 include the use of photorefractive or other electro-optical materials.

[0049] Section 26 of Figure 7 shows a modification of Section 25 of Figure 7, which utilizes a folded structure to double the depth separation given to 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 / off at a speed 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 emission cavity 1, and thus different layers in the light field can be scanned electronically and sequentially. 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, and computational techniques can be used to turn the switchable mirrors 13 in the field emission cavity 1 on and off in a way that increases the overall light efficiency or brightness of the depth used. For example, if content exists only at the nearest depth, there is no need to allocate more empty frames to other deeper depths. In other words, the signals supplied to the display panel 6 and the switchable mirror 13 can be processed in a manner that dynamically maximizes the frame rate and brightness at active depth.

[0050] Section 27 of Figure 7 illustrates an embodiment of a field-emitting cavity 1 that uses a microlens array to collimate a display panel 6 and projects digital content onto a stack of switchable diffusers. This embodiment generates digital content at multiple depths, each determined by which diffuser is configured to be diffusive. Furthermore, if the switchable diffusers are driven to achieve spatially varying diffusion, it is possible to generate a non-planar diffusion plane, thereby generating a non-planar output focal plane. The spatially varying depth of this output focal plane can then be dynamically adjusted to match the spatially varying depth of the displayed digital content. There are many techniques available for switchable diffusers, most of which rely on polymer-stabilized cholesteric texture (PSCT) optical shutter techniques. Another way to realize Section 27 of Figure 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 lenslet to rotate the polarization, which corresponds to different diffusers diffusing light at different depths. While this is theoretically feasible, such an arrangement is most likely to generate Hayes artifacts for deeper layers.

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

[0052] Section 28 of Figure 8 shows an extension of Section 25 of Figure 7, where the birefringence of a transmissive liquid crystal cell layer 16 positioned on top of the display panel 6 generates different depths. By activating more or fewer stacks of the liquid crystal cell layer 16, the apparent refractive index between the display panel 6 and the cavity exit pupil 2 can be dynamically adjusted. Thus, this extension can generate digital content at multiple different depths. The amount of required refractive index deformation depends on the design of the optical relay mechanism 3 coupled to the cavity exit pupil 2. If the optical relay mechanism 3 expands the perceived depth, small fluctuations in the optical path can result in a large shift in the focal plane depth perceived by the user.

[0053] Section 29 of Figure 8 shows an alternative to Section 28 of Figure 8, which, compared to Section 25 of Figure 7, provides a significantly larger depth step, thereby allowing for a larger depth variation range for the focal plane. This is an embodiment of a Class I field emission cavity 1 having a single-polarization display panel 6, through which light passes through a liquid crystal cell layer 16 that can rotate the incident polarization. As shown in Figure 8, due to the rest of the structure of the field emission cavity 1 (having a polarization-dependent beam splitter plate 10 and a quarter-wave plate 11 / mirror 8), it is possible to switch between two output depths using the liquid crystal cell (LCC) layer 16. In some embodiments, the LCC layer 16 does not have a 2D matrix on it and is an LCC layer 16 that rotates the polarization 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 illustrated embodiment, the display panel 6 generates horizontally polarized light (blue arrow). When the LCC layer 16 is off, light with the same polarization passes through the LCC layer 16, then through the polarization-dependent beam splitter plate 10, then hits the quarter-wave plate 11 and reflector 8, then is reflected 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 is rotated 90 degrees to become vertical, reflected from the beam splitter plate 9, directed upward, reflected from 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 Figure 8 shows an extension of Section 28 of Figure 8, which enables a single 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 compared to Section 25 of Figure 7, thereby providing a larger depth variation range for the focal plane. Each liquid crystal cell layer 16 acts like a 2D optical valve, storing angular information and defining the path that light takes depending on its polarization state. Based on the state of the LCC layer 16, three depths I, II, and III can be generated. 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. Theoretically, this design can be extended to countless field-emitting cavities, but with each additional field-emitting cavity, some of the light is lost, reducing efficiency.

[0055] Section 31 of Figure 9 shows a compact wedge cavity extension of Section 12 of Figure 4, which uses a single display 6 instead of two display panels 6 to generate digital content simultaneously at two similar depths. The depth separation between the two focal planes can be easily adjusted by adjusting the position of the single polarization-dependent beam splitter plate 10. In addition, by utilizing the polarization of the display panel 6 in conjunction with the polarization-dependent beam splitter plate 10 and waveplate 11, there is the advantage of minimizing optical loss.

[0056] Section 32 of Figure 9 shows a compact Class II modification 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. The depth separation between the two focal planes can be easily adjusted by adjusting the position of the display panels 6.

[0057] Section 33 of Figure 9 shows a compact Class I wedge for a field-emitting cavity that uses a polarizing display panel 6 to generate digital content simultaneously at two depths. Depending on the angle, light can be ejected from the cavity exit pupil 2 at a desired angle.

[0058] Depth and brightness enhancement mechanism The depth of each layer within the light field can be adjusted by using glass or other high refractive index materials in the field emission cavity 1 or cavity exit pupil 2. Furthermore, the brightness of the layers can be increased by using a prism film on the display. The display panel 6 within the field emission cavity 1 typically has a Gaussian wide-angle profile with peak intensity at the center, which is not always beneficial in a cavity-based light field where reflections from the display panel 6 can be oblique. Placing a prism film on the display panel 6 can tilt the peak intensity of the Gaussian profile to a desired angle, helping to obtain a brighter output for that layer of the screen. The reason a high refractive index glass window reduces depth is that it refracts light into a smaller cone than the original cone, and therefore the perceived depth appears slightly smaller or not as deep.

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

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

[0061] Section 35 of Figure 10 shows an example of a primary Class I field emission cavity 1 of the cavity exit pupil 2, where both depth and depth are perceived as slightly shallower inside the field emission cavity 1 due to the high refractive index 18 in the cavity exit pupil 2.

[0062] Section 36 of Figure 10 shows an example of a primary Class I field emission cavity 1 of the 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 Figure 10 shows an example of a first-order Class I field emission cavity 1 of the cavity exit pupil 2, where the deeper focal plane is slightly deeper than the cavity exit pupil 2 at a closer depth due to the high refractive index 18 on the back surface of the reflector 8.

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

[0065] Relay mechanisms and applied modalities As described above, the cavity exit pupil 2 delivers light to the relay mechanism 3, resulting in different divergence reference vertices of different focal planes presented to the user. The relay mechanism 3 can be an off-axis visor, a geometric waveguide or diffraction waveguide, a birdbath-designed 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 emission cavity 1 toward a viewer. In one example, light exits the cavity emission pupil 2 onto a visor and travels toward the eye. In another example, light exits a smaller cavity and is fed into a larger waveguide, which then redirects the light toward the observer.

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

[0068] Reference numeral 39 in Figure 11 indicates an audience for either the near-head modality 20 or the entertainment system modality 21, where the audience is more than 60 centimeters (cm) away from the display.

[0069] Reference numeral 40 in Figure 11 indicates a generalized display cavity (i.e., at least one field-emitting cavity 1) that generates digital content (stereoscopic or 2D) at one or more depths.

[0070] Reference numeral 41 in Figure 11 indicates the casing (i.e., system enclosure 5) of at least one field emission cavity 1 that holds the rest of the system's electronics.

[0071] Reference numeral 42 in Figure 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 indicates 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 change the depth of the contents coming from the original depth of the cavity to a greater or lesser distance.

[0073] Reference numeral 44 in Figure 11 indicates a coupled optical system that connects the cavity exit pupil 2 to the entrance pupil of the waveguide (i.e., relay mechanism 3).

[0074] Reference numeral 45 in Figure 11 indicates a geometric or diffracting waveguide (i.e., relay mechanism 3) that redirects the output of the FE cavity (made up of an LCoS and reflector or a DMD and reflector or an LCD panel and reflector or an array of projectors) towards the viewer. These waveguides can be multimode geometric waveguides, diffracting waveguides, or real single-mode confinement waveguides.

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

[0076] Compression design A single reflector can be bulky both inside FE cavity 1 and as a relay. Figure 12 shows several non-limiting examples of such a compressed design based on the spatial stacking of switchable mirrors.

[0077] Referring to Figure 12, an operable combination of at least one field-emitting cavity 1 and a relay mechanism 3 may comprise a plurality of switchable mirrors that communicate in series with each other and are 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, so that the plurality of first switchable mirrors 14 are distributed among the plurality of second switchable mirrors 15. As can be seen from the section of Figure 12, a particular cavity configuration is configured to selectively alternate between reflecting the optical path in a first polarization using at least one designated first switchable mirror from the plurality of first switchable mirrors 14 and passing the optical path through the designated first switchable mirror, and a particular cavity configuration is further configured to selectively alternate between reflecting the optical path in a second polarization using at least one designated second switchable mirror from the plurality of second switchable mirrors 15 and passing the optical path through the designated second switchable mirror. This configures the multiple first switchable mirrors 14 and the multiple second switchable mirrors 15 to compress the volume occupied by the operating combination of at least one field emission cavity 1 and relay mechanism 3. Section 47 of Figure 12, similar to Section 6 of Figure 3A, shows an exemplary system without compression, having a Class I FE cavity 1 and two depths. Light exits the cavity exit pupil 2 (shown by a blue dashed line), reflects off reference numeral 42 in Figure 12 (i.e., relay mechanism 3), and exits the enclosure exit pupil 4 (shown by a red dashed line). The deeper light I comes from depth I, and the light II comes from a closer distance inside the field emission cavity 1. The system is required to have a minimum thickness L mandated by the dimensions of the display panel 6. For the same dimensions of the display panel 6, Section 48 of Figure 12 reduces the thickness by half (L / 2). This compression is achieved by means of temporal switching of switchable mirrors, or by polarization, by having a stack of repeaters that are transparent to others.Therefore, in section 48 of Figure 12, the deeper depth I has two sections Ia and Ib that are relayed at two different distances; the distance in the relay functions so that Ia and Ib both have the same depth as depth I, but extend to the same size enclosure exit pupil 4 as section 47 of Figure 12. The same thing happens for the closer depth II. The depth is diced into two relays that extend the enclosure exit pupil 4 but have a thinner thickness. This approach can be expanded for further compression. Furthermore, section 49 of Figure 12 shows the case where the thickness is compressed threefold compared to section 47 of Figure 12. Here, each depth level is spatially multiplexed into three sections compensated by the heights of three relay-switchable mirrors 14, 15. For example, the paths Ia, Ib and Ic take to the enclosure exit pupil 4 (shown by the red dashed lines) are equal, and therefore they all have the same depth as depth I. However, since they are ejected at different heights, the enclosure exit pupil 4 is expanded back to the size of the enclosure exit pupil 4 in section 47 of Figure 12.

[0078] Prototype example Figure 13 shows a disassembled 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 as follows:

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

[0080] Advantages and improvements over existing methods The arrangement, methods, and assembly of components described herein offer various advantages and improvements over existing 3D systems.

[0081] ● Ergonomic advantages and improvements Accommodation-Convergence Conflict Mitigation - The present invention as described herein can generate digital content at multiple depths having true monocular wavefronts. The flexibility of displaying digital content at multiple depths allows for the presentation of digital content at optical depths that match or are similar to the binocular disparity depth cues presented to the viewer, thereby helping to resolve accommodation-convergence conflict experienced by the viewer. Mitigating accommodation-convergence conflict makes viewing digital content for extended periods more comfortable and enhances the sense of realism experienced by users viewing digital content.

[0082] ○ Size Reduction - This invention allows for the folding of the optical path, providing flexibility in terms of packaging compared to systems using projectors. This enables smaller systems.

[0083] Unlike automated stereoscopic 3D systems where the viewing zone distance and angle are limited, sometimes allowing only a small number of viewers to see the 3D content, this invention enables a viewing angle of up to 150 degrees (depending on the depth) and has no limitations on the number of users.

[0084] The FE Cavity 1 is not limited to a specific technology and can be combined with any type of panel and light engine. If necessary, an automated stereoscopic display can also be used as the engine to enhance their performance in depth accuracy.

[0085] ○ Reduced Cost - In contrast to using eye-tracking based adjustable 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] The FE Cavity 1 system enables true optical depth, allowing the enclosure exit pupil 4 to be positioned very close to the eye without eye strain. This is because the true optical depth of the image can be reduced to a greater distance. Unlike stereoscopic displays, this opens up entirely new possibilities for near-eye displays, where the display size can be enlarged without the need to wear anything or have a large screen.

[0087] For most designs in this specification that have a passive glass reflector or even a switchable mirror, the image provided by the FE cavity 1 is free from artifacts such as haze, color inconsistencies, distortion, and moiré artifacts.

[0088] ● Performance advantages and improvements Bandwidth Reduction - The present invention as described herein enables the resolution or mitigation of accommodative congestion competition without the need to present the entire 5D pre-optical functionality to the viewer. This can reduce the complexity of content rendering and improve the system frame rate compared to a full light field display. Bandwidth can be reduced by several orders of magnitude.

[0089] ○ Flexibility in Optical Efficiency - The present invention offers flexibility in that it allows for the selection of designs with high optical throughput when optical efficiency is a priority. Further flexibility is available to add more display planes or to use simpler cavity designs when display brightness is not required.

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

[0091] ○ Expandability - FE Cavity 1 is conveniently expandable in terms of architecture, number of planes, and expansion to different display systems.

[0092] ○ Compatibility - The present invention presented here offers significant compatibility advantages at both the software and hardware levels. At the software level, the light source can ultimately be a 2D screen, allowing for easy supply of conventional standard signals to the display system. This also simplifies rendering, as it eliminates the fundamental need for significant computational processing of inputs caused by depth-providing optics. The hardware architecture is essential to a wide variety of existing 2D display systems.

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

[0094] ○ Head-up displays - Since the depth can be much greater than the actual position of the display, the relay can be made semi-transparent, which is a perfect case for large-scale overlays of images and the real world, especially in the context of head-up displays.

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

[0096] Commercial applications This enables numerous commercial applications with dramatic precision in depth, screen clarity, and immersion. The following is a non-exclusive list of possible applications.

[0097] ● Navigation When driving or piloting, use the head-up display to determine turn-by-turn directions without having to look down at the road or get lost using a phone or other navigation device.

[0098] ●Medical ○ Better investigation of 3D data files using a light field display.

[0099] ● Workplace ergonomics The enlarged display can replace a large display without the need for any additional hardware or a large screen. The display's 3D capabilities can provide office-use volume with pixel accuracy equivalent to today's standard monitors.

[0100] ● Entertainment The layered nature of FE Cavity 1 facilitates content generation for the gaming and video industries. This is because rendering in several layers to provide 3D effects is far easier (less computationally demanding) than rendering an entire 3D environment.

[0101] The FE Cavity 1 is well-suited for standalone game consoles because its true depth captivates viewers with a new experience.

[0102] ●Design This invention allows users to preview the appearance 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. This is crucial because developers cannot wear headsets for hours on end, yet the invention can be used with true optical depth.

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

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

[0105] The aperture optical element 70 may include, but is not limited to, an anti-reflective layer, a prism film 17, a privacy layer, an absorbing polarizer, or a microcurtain layer, and may include any number of light correction devices. The aperture optical element 70 may also be used to correct ambient light directed from the external environment towards the user. As an exemplary example, an anti-reflective layer can be used as the aperture optical element 70 to eliminate stray light reflections entering the observer's eye. The aperture optical element 70 may have the additional function of protecting components within the system enclosure 5 from the external environment. In some embodiments, the aperture optical element 70 may be positioned in both the cavity exit pupil 2 and the enclosure exit pupil 4.

[0106] In this disclosure, a field emission cavity can generate a light field display, or a subsampled light field display, i.e., a light field display that substantially 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 present invention, these reflective elements 72 and semi-reflective elements 71 are configured such that light in the optical path is at least partially folded over itself in order to selectively adjust the virtual depth position of the virtual image presented to the viewer. In other words, the field emission cavity 1, reflective elements 72, and semi-reflective elements 71 are configured such that a portion of the optical path is folded back over the original optical path in order to adjust the depth of the focal plane along the optical path. This folding of the optical path itself allows the present invention to further adjust the virtual depth position of the virtual image. Further embodiments include a switchable mirror or mechanical actuator within the field emission cavity 1 configured to further adjust the virtual depth position of the virtual image.

[0108] Figure 15 shows a further embodiment of the field emission cavity 1 in which the semi-reflective elements 71 of the system are segmented to generate multiple depths through the expanded aperture optical elements 70. In some embodiments, the display panel 6 itself can be segmented. In other embodiments, the reflective optical system 72 or the semi-reflective optical system 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 varying reflection coefficients or reflectances across its surface. The variation may be smooth, continuous, piecewise constant, or piecewise smooth. A segmented display panel is a display panel that displays different image content in different regions of the display panel. For example, a display panel segmented into two regions may display a first image and a second image. In this way, light emitted from different segments of a segmented element, transmitted through them, or reflected through them can travel along different paths through the display system.

[0110] This segmentation of the component 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 created by the segmented component. Furthermore, similarly, the reflective 72 optical system or the semi-reflective 71 optical system can also be segmented into a first segmented element and a second segmented element. Any component within the present invention can be segmented in this same manner. Exemplary embodiments having segmented elements are shown in Figures 15 and 17.

[0111] Furthermore, the reflective 72 optical system or the semi-reflective 71 optical system may have gradient characteristics such as gradient reflectivity. The reflective 72 optical system or the semi-reflective 71 optical system, including the segmented optical system, may be polarization-dependent such that, after interacting with a polarization-dependent element, light of the first polarization travels through the first optical path and light of the second polarization travels through the second optical path.

[0112] As shown in Figure 15, the light in the optical path may be guided along a cavity formed between two or more reflectors, elements, optical systems, or components that constitute the optical pipe. The light in the optical tube is guided through the aperture optical element 70 to the bottom of the cavity of the optical tube where it exits the optical tube. The light is directed towards the 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 and second segmented elements consist of polarization-dependent elements. The polarization-dependent elements of the first and second segmented elements are configured such that light of first polarization is guided along the light tube along the first optical path, and light of second polarization is guided along the light tube along the second optical path. This causes the light pipe to generate multiple virtual images at multiple depths. In some embodiments, the optical paths corresponding to different segmented elements form images at the same depth but different lateral positions, and as a result, they together form a single virtual image with an expanded aperture or field of view. In some embodiments, this polarization-dependent element light pipe is embedded in or integrated with the vehicle.

[0114] A further embodiment shown in Figure 16 has a field emission cavity 1 having an exit opening that optically communicates with a large mirror 79. The mirror can partially function as an aperture optical component. This embodiment further comprises a gesture sensor 80, a depth camera 80, or both. The gesture sensor 80 or depth camera 80 is coupled to 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 viewer 77's movements, position, and gestures. 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 can be manipulated by the observer through the depth camera 80 or gesture sensor 80.

[0115] In this embodiment, the field emission cavity 1 is configured to generate a virtual image 81, which includes, but is not limited to, any number of items such as text or images. This virtual image 81 is generated by the field emission cavity 1 and appears at a virtual depth similar to the observer's reflection 82 in the mirror. In other words, when an observer looks at those reflections 82 in the mirror, the virtual image 81 generated by the field emission cavity 1 appears to be at the same depth as the reflections 82 in the mirror, or to be on the same plane.

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

[0117] Figure 17 shows a further embodiment in which the field emission cavity 1 is embedded in or integrated with the roof 75 or ceiling of the vehicle 76. In this further embodiment, similar to embodiment 33 in Figure 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 positioned at an angle of less than 45 degrees to each other. This angle can be arbitrarily designed. 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 characteristics may be temporally switchable such that light travels along a first path at a first time and subsequent light travels along 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 at which the light travels becomes shallower. This creates a light pipe that guides the light from the exit of the display system toward 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 from that of any of the components of the display system and the roof or ceiling. When the viewer looks straight into the roof of the vehicle, they do not see the virtual image. In some embodiments, an aperture optical element 70 is used. In some embodiments, a relay mechanism 3 is used. In some embodiments, components of the display system, such as a second segment element, function simultaneously as an aperture optical system, a relay mechanism, and an optical tuning mechanism, or a subset thereof.

[0118] In some embodiments, the optical path may be influenced by polarization-dependent elements. For example, a semi-reflective element may be provided with a polarization-dependent grating that guides light of a first polarization along a first path and light of a second polarization along a second path. The polarization of the light can be modified using quarter-wave plates and reflective polarizers.

[0119] In some embodiments, the field emission cavity may further include retroreflective or retrorefracting elements so that the virtual image appears closer to the observer rather than further away. Similar to the embodiment in Figure 16, a gesture camera or depth sensor may 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 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 in Figure 17 is an example of the wedge-shaped cavity described in Figure 9, but it can also be configured as a field-emitting cavity of other classes or orders such that the optical path folds precisely or nearly onto itself. In such cavities, light can fold when it receives multiple reflections from a single element.

[0121] The embodiment shown in Figure 17 may be integrated into a part of a vehicle. Although the embodiments described herein represent automobiles or vehicles, vehicles can take other forms, including, but are not limited to, automobiles, trucks, motorcycles, tricycles, tanks, aircraft, or watercraft.

[0122] It is important to note that each point of the virtual image is visible to both eyes of a human observer, that is, light rays from any given point of the virtual image enter both eyes simultaneously. The viewer's eyes can be positioned anywhere within a given volume to see the virtual image. The depth of the virtual image is the depth to which each eye adapts or focuses. This quantity is called the headbox and spans the 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 within 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 partially limited by the viewing direction required to see the virtual image.

[0123] Furthermore, 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 diverge or collimate. When image-forming rays are projected geometrically backward, their projections intersect. This intersection 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, the virtual image is observed by the observer.

[0124] In some embodiments, the first element 73 or the second element 74 in Figure 17 is 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, which 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 waveplate, a beam splitter or other semi-reflector, and a second waveplate. In some embodiments, the waveplate is a quarter-waveplate. 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) polarization is converted to y(x) polarization. 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, which 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 waveplate. In some embodiments, the waveplate is a quarter-wave plate. Incident linearly polarized light is reflected, and the polarization direction is rotated by 90 degrees.

[0126] The polarization state under consideration may be linearly polarized, circularly polarized, or elliptically polarized. In some embodiments, the degree of polarization is included in the polarization state.

[0127] In some embodiments, the first element 73 or the second element 74 is a reflective polarizer that transmits light in a first polarization state and reflects light in 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 an electronic signal. For example, the waveplates in the polarization-changing (semi)reflector described above may be liquid crystal (LC) such as nematic LC or cholesteric LC. When a first voltage is applied to the waveplate, light is transmitted without changing its polarization (thus preserving the polarization), and when a second voltage is applied, the polarization is changed from the first state to the second state, such as from horizontal polarization to vertical polarization. The voltage value can be designed arbitrarily and includes 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 by 90 degrees. At the second voltage, it can be rotated by 0 degrees. At the third voltage, the incident linear polarization can be converted to circular polarization. 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] Figures 18A–18F show a set of embodiments related to Figure 17. In Figure 18A, light having a first polarization state is emitted from the display 6 and incident on the field emission cavity 1. In all embodiments shown in Figures 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 by 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 is incident on it a second time. The transmitted light passes through the aperture optical element 70 and exits the cavity to the outside. In some embodiments, the aperture optical element 70 includes an absorptive polarizer and an anti-reflective layer. In some embodiments, the aperture optical element is a transparent material such as a glass layer.

[0130] When light is seen by the observer, it forms a virtual image 78 that is further away from the observer than the field emission cavity itself. Furthermore, the angle of the first element 73 with respect to the second element 74 is less than 45 degrees, and as a result, the orientation of the virtual image is shallower than relative to the display itself. Moreover, because the angle is less than 45 degrees, the field emission cavity can be made thinner.

[0131] Any electronically accessible or electrically active elements of the display system and cavity are controlled by 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 integrated part of the display system and functions to provide virtual image content.

[0132] Figure 18B shows an embodiment in which the display 6 is substantially parallel to the aperture optical element 70. The display transmits light through a first element 73, which may be a polarization-changing semi-reflector. The polarization state is rotated by 90 degrees, reflected by a second element 74, which may be a reflective polarizer or PBS, and then reflected again by the first element 73, which rotates the polarization by another 90 degrees so that it is 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 farther than the field emission cavity 1 and further than the display 6 itself. Circuit block 1801 controls the display content. In some embodiments, the polarization-changing semi-reflector includes a first waveplate, a beam splitter, and a second waveplate. In some embodiments, the aperture optical element 70 includes an absorptive polarizer and / or an anti-reflective element. These are merely 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 a FEC, light is reflected back and forth or circulated between the elements of the cavity. Each of these propagations is a path. For example, an FEC may 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 path. When light, or a selected portion of light, is reflected back from the second element to the first element, the propagation is called a backward pass, as the light propagates backward towards the light source. In this cavity, a round trip occurs when the light completes one cycle (forward and backward paths) and returns to the first element. In some embodiments, a round trip occurs when the light substantially reverses direction and is incident on the element two or more times. The term “round trip” refers to the number of times light circulates or bounces back and forth between two elements of a cavity, or the number of times light interacts with a single element.

[0134] In some embodiments, the light travels one round trip within the 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 1.1–2, 1.5–3, or 2–5, etc. In some embodiments, the monocular depth is dynamically adjustable by changing the characteristics of the virtual display system.

[0135] In the embodiment shown in Figure 18A, there is one round trip. In the embodiment shown in Figure 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 modified so that most of the light is reflected a second time by the second element. Furthermore, the second element may also include polarization-modulating elements such as waveplates or LCs to correct the polarization of the light it reflects. Moreover, the polarization changes of these elements, as well as both reflectance and transmittance, can be functions of angle. For example, either element may include a multilayer film. In such embodiments, the angle of the ray changes with each round trip so that the light can be substantially transmitted by the second element after reaching a desired angle.

[0136] Figure 18C shows an embodiment similar to Figure 18B. Light from the display 6 passes through a precavity element 1804 which includes a directional coating in some embodiments. The directional coating selectively transmits light rays oriented at angles within a specific 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 (focusing) power source. In some embodiments, the directional coating transmits angular ranges that do not start at zero degrees.

[0137] Next, the light passes through a first element 73, which is a polarization-changing semi-reflector. The light is reflected by a 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 an aperture optical element 70. In some embodiments, the aperture optical element 70 is an absorptive 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. Circuit block 1801 controls the display content and any active components such as LC or electro-optical material that may be contained in the first element 73 or the second element 74. The angle between the first and second elements is θ, which is less than 45 degrees.

[0138] Figure 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 polarization exiting 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 by its polarization, and then passes through the second element and the aperture optical element 70 to form a virtual image 78. The curvature of the elements generates refractive power, allowing the image to be enlarged or reduced and its depth adjusted. In some embodiments, the curved elements are coatings on a curved substrate. In some embodiments, the curved elements are free-form elements, and the curvature or shape of the elements is defined by their 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] Figure 18E shows an embodiment in which a 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 circuit block 1801, the EO material 1803 has a first refractive index, and when a second voltage is applied, it takes on a second refractive index. In some embodiments, the refractive index is not uniform but changes linearly across the elements, so that as the applied voltage changes, the refractive index changes, making the EO material 1803 an electrically controllable prism. For example, if the transverse refractive index is n(x) = n0 + A(V)x, where x is position and A(V) is a function of the applied voltage, then the light is deflected in a direction dependent on A(V). Thus, the light emitted by the display 6 passes through the first element 73, is reflected by the second element 74, reflected by the first element, and transmitted through the EO material 1803. It is thereby deflected and transmitted through the aperture optical element 70. The deflection may be in a first direction 1802A that generates a first virtual image 78A, or in a second direction 1802B that generates 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 a combination of distortion and any aberrations results in a sharp virtual image. In some embodiments, the function n(x) is not linear, but rather a function that changes to minimize the aberration. For example, the function may be a polynomial of a degree higher than 1, a logarithmic function, an exponential function, etc.

[0141] Figure 18F shows an embodiment in which light from the display 6 is incident on 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 so 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 embodiments described above, the directional coating may cover the display panel to tilt the synchrotron radiation in a preferred direction before it enters the field emission cavity.

[0143] The 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. Let the angle between them be called θ, then the tilt of the light accumulates by approximately 2θ after each round trip within the FEC. Thus, when θ is in the range of 1 to 30 degrees, the virtual image is tiled relative to the display by a range of 2 to 60 degrees after one round trip. When θ is in the range of 1 to 10 degrees, the virtual image is tiled relative to the display by a range of 3 to 30 degrees after two round trips.

[0144] Another advantage is the thinness of the display system. When the width is W ~ 30 cm and the angle θ is 30 degrees, the thickness of the FEC is approximately W tan θ, i.e., 17 cm. The shallower the angle, the thinner the display system becomes. The thickness of the display may be 5 cm, 10 cm, 20 cm, or 30 cm. 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] Figures 19A to 19F illustrate embodiments in which the above-described display system is integrated into a vehicle. Figure 19A is an embodiment in which the display system 1900 is integrated into a vehicle. The elements of the display system include the display itself, a field emission cavity, and optional 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 component 1901A. In some embodiments, the display system 1900 is overlaid on a window, allowing light from an external scene 1902 to pass through it so that a virtual image 78 overlaps with the scene, creating an augmented reality (AR) environment. In some embodiments, the display system 1900 is connected to the surface of a vehicle component 1901B. Vehicle components 1901A and 1901B may be, for example, a roof, side panels, doors, seats, seatbacks, windows, or mirrors, for example, but are not limited to these. Because the display system is thin (due to the sharp angle between the first and second elements), it is virtually flush with the vehicle's surface, and any recessed cavity takes up very little space to accommodate it when not in use. A bulkier display would occupy more space and would typically require a folding mechanism when not in use or when more space is needed within the vehicle.

[0146] The arrangement of the present invention is subject to limitations determined by the lateral size, the distance to the observer, and the viewing direction for viewing the obliquely oriented virtual image. Specifically, a virtual line extending from the observer's eye to the virtual image must pass through the aperture optical component (or the geometric surface on which the aperture optical component may be placed). This is not the case, for example, with a display system having relatively small lateral dimensions and positioned close to the observer.

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

[0148] Figure 19C shows an embodiment in which the display system 1900 is integrated into a vehicle component 1901, which is the roof of the car, and the display system is at least partially transparent. 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 of the vehicle. In some embodiments, there is a separate sunroof 1905, and the display system and sunroof are independently controlled by a first mechanical track 1904A and a second mechanical track 1904B.

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

[0150] Figure 19E shows an embodiment in which the display system 1900 may be located within a recess in a vehicle component 1901. A pair of hinges 1906A, 1906B move the display system into place in front of the second vehicle component 1901A. A third hinge 1906C moves the panel 1907, enabling the movement of the display system. Vehicle components 1901A and 1901 may be parts of a seat in a vehicle. A 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 combining the aspects of Figures 19A and 19D. The entire display system 1901 is connected to the vehicle component 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 remains fixed. In some embodiments, the hinge is instead an articulated arm or ball joint that can rotate the display system in multiple directions, i.e., it can rotate around different axes of rotation.

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

[0153] Figures 20A to 20E illustrate embodiments of a display system in a vehicle. In Figure 20A, a vehicle 76 houses two display systems 1900. These may be the display systems described above. Light exits 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, assists in collimating light, and forms a virtual image 78 with a very great depth outside the vehicle.

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

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

[0156] Figure 20D shows an embodiment in which the display system 1900 is fixed to the roof 75 of the vehicle 76, forming a virtual image 78 above the vehicle. In some embodiments, the display system is partially transparent, allowing external light to pass through it, and as a result, the 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 vehicle's coordinates or orientation relative to the environment. In some embodiments, a simultaneous localization and mapping (SLAM) module is coupled to the display system. The SLAM module uses a computational algorithm 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] Figure 20E, similar to Figure 16, shows an embodiment in which the display system 1900 is integrated to perform the function of a conventional mirror in a vehicle. In this embodiment, content from the external environment is captured by a camera 2004 fixed to the external portion of the scene. In some vehicles, the camera is located almost in the position of a conventional side mirror, and no side mirror is present. The camera captures information about the environment to the side of the vehicle and can display it on the display system 1900 fixed to the interior of the vehicle 76, for example, in an interior door 2005. In some embodiments, the camera captures information about the rear of the vehicle and displays it on the display system 1900 fixed to the vehicle by an arm 2006, for example, instead of a conventional rearview mirror. The advantage of this scenario is that, compared to a conventional “digital mirror” which is simply a display panel that replaces a mirror, the depth related to objects in the external environment can be preserved by the depth of the virtual image in the display system.

[0158] While 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 claimed below.

[0159] This specification can algorithmically describe various embodiments. Exemplary algorithms may be provided, but desired functions can be implemented in any suitable way. Those skilled in the art can implement such functions or algorithms, for example, in hardware, in software, or in a combination of hardware and software. Modules (e.g., “GPS module,” “SLAM module”) may comprise hardware and / or software to implement the disclosed functions or algorithms. For example, in some embodiments, an algorithm may be implemented through a module having one or more processors that execute computer code stored on one or more non-temporary computer-readable storage media. In some embodiments, a function is implemented at least partially through a module having dedicated hardware (e.g., ASIC, FPGA). In some embodiments, modules may share components. For example, both a first function module and a second function module may 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 either a hardware module or a software module. A hardware module includes or shares hardware for implementing the module's functionality. A hardware module may also include software, i.e., a software module. A software module may include, for example, information that can be stored on a non-temporary computer-readable storage medium. In some embodiments, the information may include instructions that can be executed by one or more processors. In some embodiments, the information may be used at least partially to configure hardware such as an FPGA. In some embodiments, an algorithm can be recorded as a software module. This 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 its information to configure hardware.

[0161] In this specification, “machine-readable media,” “computer-readable media,” and similar terms are used to refer to volatile or non-volatile non-temporary media that store data and / or instructions that cause a machine to operate in a particular manner. Common forms of machine-readable media include, for example, hard disks, solid-state drives, magnetic tapes, or any other magnetic data storage media, optical discs, or any other optical data storage media, any physical media having a pattern of holes, RAM, PROM, EPROM, FLASH-EPROM, NVRAM, any other memory chips or cartridges, and their networked versions.

[0162] These and various other forms of computer-readable media may be involved in transporting one or more sequences of one or more instructions to a processing device for execution. Such instructions embodied on the media are referred to as “instructions” or “codes,” and instructions may be grouped in the formation of computer programs or other groupings. When executed, such instructions may enable a processing device to perform the features or functions of the present application discussed herein.

[0163] In this specification, a “processing device” may be implemented as a single processor that performs processing operations, or as a combination of dedicated 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 circuits.

[0164] The various embodiments described herein are illustrated with reference to exemplary block diagrams, flowcharts, and other figures. As will become apparent to one of the ordinary skills of the art after reading this specification, the illustrated embodiments and their various alternative forms can be implemented without being limited to the illustrated examples. For example, block diagrams and their accompanying descriptions should not be constructed as requiring a particular architecture or configuration.

[0165] Each of the processes, methods, and algorithms described in the previous section may be embodied in code components executed by one or more computer systems or computer processors comprising computer hardware, and may be fully or partially automated. 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 combined in several ways. Different combinations and subcombinations are intended to fall within the scope of this disclosure, and some implementations may omit certain method or process blocks. Furthermore, unless the context indicates otherwise, the methods and processes described herein are not limited to any particular sequence, and any associated blocks or states may be executed in other appropriate sequences, in parallel, or in some other way. Blocks or states may be added to or removed from the disclosed exemplary embodiments. The performance of a particular operation or process may be distributed across computer systems or computer processors deployed across several computing resources, as well as residing within a single machine.

[0166] As used herein, the term “or” may be constructed in an inclusive or exclusive sense. Furthermore, descriptions of resources, actions, or structures in the singular should not be interpreted as excluding the plural. Unless otherwise specified or understood in the context in which they are used, conditional language such as “can,” “could,” “may,” or “may” is generally intended to convey that certain embodiments include certain features, elements, and / or steps that other embodiments do not.

[0167] The terms and phrases used herein, and their variations thereof, are not limiting and should be construed as open-ended unless otherwise specified. The purposes of terms such as “conventional,” “precedent,” “ordinary,” “standard,” “known,” and similar terms should not be construed as limiting the items described over a given period or to items available at a given time, but rather as encompassing conventional, precedent, ordinary, or standard techniques that may be available or known at any point in the present or future. The presence of broader phrases such as “one or more,” “at least,” or “not limited to,” or other similar phrases, should not be construed as meaning that a narrower case is intended or required in the absence of such broader phrases.

Claims

1. It is a display system, A display panel that emits light; A field emission cavity that guides the light from the display panel along a path to generate a virtual image directed obliquely to the display panel; Equipped with, The aforementioned field discharge cavity is A polarization-changing reflector arranged along the aforementioned path, which converts the 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, which reflects the second polarization of light and transmits the first polarization of light; An aperture optical element that transmits the light so as to move away from the field emission cavity; Having, Display system.

2. The display system according to claim 1, further comprising a vehicle having the display panel and the field discharge cavity mounted inside.

3. The display system according to claim 2, characterized in that the depth of the virtual image is located outside the vehicle.

4. The display system according to claim 2, further comprising a camera for capturing information about the external environment, wherein the virtual image is based on the information.

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

6. The display system according to claim 1, wherein the aperture optical element comprises an absorptive polarizer and an anti-reflective layer.

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

8. The display system according to claim 1, wherein the display panel and the field emission cavity are attached to a vehicle component selected from the group consisting of doors, seats, floors, and side panels.

9. The display system according to claim 1, further comprising a directional coating arranged along the aforementioned path.

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

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

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

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

14. It is a display system, A display panel that emits light; A field emission cavity that guides the light from the display panel along a path to generate a virtual image oriented obliquely to the display panel; Equipped with, The aforementioned field discharge cavity is A polarization-changing semi-reflector arranged to transmit and convert the aforementioned light from a first polarization to a second polarization; A polarization-dependent reflector positioned along the path after the polarization-changing semi-reflector at an angle of less than 45 degrees with respect to the polarization-changing semi-reflector; An aperture optical element that transmits the light so as to move away from the field emission cavity; Having, Display system.

15. The display system according to claim 14, further comprising a vehicle having the display panel and the field emission cavity mounted inside.

16. The display system according to claim 15, characterized in that the depth of the virtual image is located outside the vehicle.

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

18. The display system according to claim 15, further comprising a camera for capturing information about the external environment, wherein the display panel and the field emission cavity are mounted inside the vehicle, and the virtual image is based on the information.

19. The display system according to claim 15, further comprising a movable joint having a first part and a second part, wherein the first part and the second part move relative to each other as the movable joint moves, the first part is attached to the vehicle, and at least one of the field emission cavity, the display panel, and the aperture optical element is attached to the second part.

20. The display system according to claim 14, wherein the polarization-changing semi-reflector comprises a first waveplate, a beam splitter, and a second waveplate.

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

22. The display system according to claim 14, wherein the aperture optical element comprises an absorptive polarizer and an anti-reflective layer.

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

24. The display system according to claim 14, wherein the display panel and the field emission cavity are attached to a vehicle component selected from the group consisting of doors, seats, floors, side panels and windows.

25. The display system according to claim 14, further comprising a directional coating arranged along the aforementioned path.

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

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

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

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

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

31. The display system according to claim 30, wherein the polarization-dependent reflector is curved.

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

33. It is an in-vehicle display system, A display panel that emits light; A field emission cavity that guides the light from the display panel and generates a virtual image, Multiple polarization-dependent semi-reflectors; Aperture optical element; A field discharge cavity having; A vehicle equipped with the aforementioned display panel and the aforementioned field discharge cavity; Equipped with, The depth of the virtual image is located outside the vehicle. In-car display system.

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

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

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

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

38. The in-vehicle display system according to claim 33, further comprising a camera for capturing information about the external environment, wherein the display panel and the field emission cavity are mounted relative to the mirror of the vehicle, and the virtual image is based on the information.

39. The in-vehicle display system according to claim 33, wherein the light travels back and forth multiple times within the field emission cavity.

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