Novel waveguide system for near-eye display

Abstract

A waveguide system for a near-eye display may include a first waveguide portion and a second waveguide portion. The first waveguide portion may include a first set of at least partially reflective surfaces configured to couple light corresponding to the image out of the first waveguide portion to enlarge the aperture in a first dimension. The second waveguide portion may be disposed on one side of the first waveguide portion and configured to receive light from the first waveguide portion, and the second waveguide portion includes a second set of partially reflective surfaces configured to couple out light corresponding to an image, the aperture is expanded in a second dimension that is not parallel to the first dimension.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of near-eye display systems, such as head-mounted displays. More specifically, the present disclosure relates to compact waveguide systems designed for near-eye displays (NEDs). BACKGROUND

[0002] Consumer demand for improved human-machine interfaces has led to increased interest in high-quality image head-mounted displays (HMDs) or near-eye displays (NEDs), often referred to as smart glasses. These devices can provide virtual reality (VR) experiences or augmented reality (AR) experiences that enhance the way users interact with digital content and their surroundings.

[0003] Consumers seek better image quality, immersive experiences, and greater comfort when using HMDs. Consumers desire displays with high resolution, vivid colors, and minimal distortion to produce realistic and engaging viewing experiences. In addition, comfort is a key factor, as users often wear these devices for extended periods of time. Consumers want lightweight, sleek designs that are less conspicuous and more convenient to wear in a variety of scenarios. Smaller devices also provide improved portability, making these devices easier to carry and use in different environments. Thus, there is a growing demand for higher performance but smaller and more compact HMDs.

[0004] A key component in conventional near-eye display systems is the waveguide. The waveguide is a device that directs light from the system image projector to the user's eye. The waveguide relies on total internal reflection along the primary surfaces within the device to propagate light. There are inherent limitations to the miniaturization of waveguides, which in turn limits the miniaturization of head-mounted displays. For example, conventional features that facilitate more efficient illumination of the waveguide tend to increase the size of the waveguide. In another example, conventional features that facilitate miniaturization of the waveguide tend to degrade the image quality or aesthetics of the near-eye display system.

[0005] Another key component of near-eye display systems is the projector. For HMDs and NEDs, the image projector is a device that generates visual content and projects it onto an intermediate medium (i.e., a waveguide) for delivery to the eye. The goal is to provide the user with an image or video perception, often with a depth or three-dimensional illusion. Conventional projectors do not facilitate the compactness that is an established goal for HMDs.

[0006] Accordingly, there is a need for innovative compact illumination systems that include compact waveguide systems for improving the compactness of NEDs and novel projectors. SUMMARY

[0007] The present disclosure aims at exploiting reflective elements to reduce the size of waveguide systems. In one embodiment, the reflective elements allow folding the interface between a first waveguide portion (HLOE) and a second waveguide portion (LOE) in a waveguide system, thereby reducing its overall size. In another embodiment, the reflective elements allow the introduction of illumination enhancement elements hidden within the frame of a near-eye display.

[0008] The present disclosure also relates to a projector design that enables the miniaturization of waveguide elements by selectively effectively projecting light beams corresponding to a projected image.

[0009] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate various example systems, methods, and other implementations of aspects of the application. It will be appreciated that the illustrated element boundaries (e.g., boxes, groups of boxes, or other shapes) in the figures represent one example of boundaries. It will be understood that one element can be designed as multiple elements or that multiple elements can be designed as one element. An element shown as an internal component of another element can be implemented as an external component and vice versa. Further, elements can not be drawn to scale. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1A An example near-eye display (NED) is shown.

[0011] Figure 1B A two-dimensional aperture expansion (aperture multiplication) concept for a NED is schematically shown.

[0012] Figure 2 A new waveguide system for a NED is shown.

[0013] Figure 3 A new waveguide system for a NED is shown.

[0014] Figure 4 A new waveguide system for a NED is shown.

[0015] Figure 5 A waveguide system for two-dimensional aperture expansion is shown.

[0016] Figure 6A An alternative waveguide system for two-dimensional aperture expansion is shown.

[0017] Figure 6B An alternative waveguide system for two-dimensional aperture expansion is shown.

[0018] Figure 7 A schematic of an example projector for controlling the light beam distribution at the projector aperture is shown.

[0019] Figure 8A A schematic diagram of another example projector for controlling the beam distribution at the aperture of the projector is shown.

[0020] Figure 8B A schematic diagram of another example projector corresponding to the projector of Figure 8A but using LCOS technology and a polarizing beam splitter (PBS) is shown.

[0021] Figure 9A A schematic diagram of another example projector designed to control the beam distribution at the aperture of the projector is shown.

[0022] Figure 9B A schematic diagram of another example projector corresponding to the projector of Figure 9A but using LCOS technology and a polarizing beam splitter (PBS) is shown.

[0023] Figure 10A A schematic diagram of another example projector for controlling the beam distribution at the aperture of the projector is shown.

[0024] Figure 10B A schematic diagram of another example projector corresponding to the projector of Figure 10A but using a polarizing beam splitter (PBS) is shown.

[0025] Figures 11A, 11B and Figure 11C show another waveguide system similar to the system of Figure 5 but modified so that the waveplates are located at the edges of the waveguide system.

[0026] Figure 12A shows another waveguide system similar to the system of Figure 11A but modified to include at least one modified partial reflector.

[0027] Figure 12B shows a first alternative enlarged view of the system of Figure 12A.

[0028] Figure 13A and Figure 13B show a waveguide system corresponding to the configuration of Figure 12A.

[0029] Figures 14A, 14B and 14C show an example production process for constructing the system shown in Figure 12A.

[0030] Figure 15 shows a waveguide system similar to the system of Figure 12A but here the reflective surface is split into parallel reflective surfaces.

[0031] FIGS. 16A, 16B, and 16C illustrate a waveguide system that combines features of the system of FIG. 6 and the system of FIG. 12A. DETAILED DESCRIPTION

[0032] Certain embodiments of the present application provide optical systems and light projection systems for the purpose of optical aperture expansion for, for example, head-mounted displays (HMDs) or near-eye displays (often referred to as smart glasses), which can be virtual reality or augmented reality displays. The demand for better and more comfortable human-machine interfaces has spurred the demand for better image quality as well as smaller devices.

[0033] In Figure 1A An exemplary implementation of a device in the form of a near-eye display employing the teachings of embodiments of the present application in a waveguide system 10 is schematically illustrated in FIG. 16A, which is generally denoted by near-eye display 1. The near-eye display (NED) 1 employs a compact image projector (or "POD") 12 that is optically coupled to inject an image into a waveguide system (interchangeably referred to as "substrate" or "slab") 10, within which the image light is trapped in one dimension by internal reflection at a set of mutually parallel planar outer surfaces.

[0034] Optical aperture expansion is achieved within the waveguide system 10 by one or more arrangements for progressively redirecting the image illumination, which typically employs a set of partially reflective surfaces (interchangeably referred to as "facets"), which are mutually parallel and obliquely tilted with respect to the propagation direction of the image light, where each successive facet deflects a portion of the image light to a deflected direction. As Figure 1A Two-dimensional aperture expansion is achieved by employing a first waveguide portion 14 that transports light along the X direction and a first set of facets within the waveguide portion 14 for progressively redirecting the image illumination along the Y direction within the waveguide system 10, which is also trapped / guided by internal reflection, as shown in FIG. 16B.

[0035] The deflected image illumination then enters into a second waveguide portion 16, which can be implemented as an adjacent different substrate or as a continuation of the single substrate, within which a coupling-out arrangement (e.g., another set of partially reflective facets) progressively couples out a portion of the image illumination in the Z direction toward an eye of an observer located within a portion defined as an eye-motion box (EMB), thereby achieving optical aperture expansion in the second dimension. Similar functionality can be obtained using Diffractive Optical Elements (DOEs) to redirect and / or couple out the image illumination within one or both of the first waveguide portion 14 and the second waveguide portion 16.

[0036] The overall apparatus can be implemented separately for each eye, and preferably supported relative to the head of the user, with each waveguide system 10 facing a corresponding eye of the user. In one particularly preferred option as shown here, the support arrangement is implemented as an eyeglasses frame 18 having sides for supporting the apparatus relative to the ears of the user. Other forms of support apparatus can also be used, including but not limited to a headband, a visor, or a device suspended from a helmet.

[0037] Reference is made herein in the drawings and claims to an X-axis, a Y-axis, and a Z-axis, with the X-axis extending horizontally (or vertically in alternative implementations) along the general direction of extension of the first portion 14 of the waveguide system 10, the Y-axis extending perpendicular to the X-axis (i.e. vertically in the orientation shown here, or horizontally in alternative implementations), and the Z-axis extending perpendicular to both (i.e. horizontally towards the eye of the user). Figure 1A Figure 1A The orientation shown can be considered a "top-down" implementation, with the image illumination entering the second portion 16 of the waveguide system 10 entering from the top edge, while an alternative orientation can be considered a "side-injection" implementation, with the Y-axis referred to here being deployed horizontally.

[0038] In the remaining drawings, various features of certain implementations of the application will be shown in the context of a "top-down" orientation similar to that of Figure 1A However, it will be recognized that all of these features are equally applicable to a side-injection implementation as well, which also falls within the scope of the application. In certain cases, other intermediate orientations can also be applicable, and are included within the scope of the application unless explicitly excluded. The two-dimensional expansion implementations shown here are merely exemplary, but the application is also applicable to implementations in which the waveguide system 10 performs only a single-dimensional aperture expansion.

[0039] It will be recognized that the near-eye display 1 includes various additional components, typically including a controller 19 for actuating the image projector 12, which typically draws power from a small onboard battery (not shown) or some other suitable power source. It will be understood that the controller 19 includes all of the necessary electronic components for driving the image projector 12, such as at least one processor or processing circuit.

[0040] Large field-of-view waveguides for NEDs, such as the waveguide system 10, require a large surface area, which is not always available from an ergonomic perspective. Figure 1B ​The concept of two-dimensional aperture expansion (aperture multiplication) for NED is schematically illustrated. Image projector 12 projects a collimated light beam representing an image at infinity (two arrows represent light beams of the image edges). The light beam from projector 12 enters waveguide system 10 and propagates, while propagating, guided in one dimension by total internal reflection (TIR) and diverging in the other dimension (different light beams of different parts of the image diverge). As shown in the top view of (a) in Figure 1B The light beam propagates within waveguide system 10, specifically first part 14 (also referred to as HLOE), by total internal reflection. As shown in the front view of (b) in Figure 1B The light beam hits embedded partial reflector 14a of first part 14 and is redirected towards partial reflector 16a of second part 16 (also referred to as LOE), as shown in the side view of (c) in Figure 1B Partial reflector 16a reflects the light beam out of waveguide system 10 and towards the observer or eye-motion box (EMB) 17.

[0041] Partial reflector 14a and partial reflector 16a multiply the aperture in the lateral and longitudinal directions, respectively. The length, position and pitch of facets 14a and 16a can be different (shown as same distance for clarity) for optimal and uniform projected image. Facets 14a and 16a can be perpendicular or tilted with respect to the outer surface of HLOE 14 and LOE 16, respectively. Waveplates can be introduced between HLOE 14 and LOE 16 for improved reflectivity. Longitudinal partial reflectors (homogenizers) can be introduced before HLOE 14 (improve light injection) or after HLOE 14 for better image uniformity.

[0042] The solution for 2D expansion with the aforementioned HLOE and LOE can be purchased from Lumus Ltd. (Israel) and details of such waveguide systems can be found, for example, in commonly owned International Patent Application Publication WO 2020 / 049542 Al.

[0043] Figure 1A and Figure 1BThe waveguide system 10 in the NED is relatively large, especially in the height (Y) dimension, which makes the corresponding NED 1 relatively large and bulky. However, NED users seek greater comfort. Comfort is a key factor because users often wear these devices for extended periods. Consumers desire lightweight, sleek designs that are less conspicuous and easier to wear in various settings. Smaller devices also offer improved portability, making them easier to carry and use in different environments. Therefore, there is a growing demand for smaller, more compact NEDs. Waveguide miniaturization can make NEDs smaller and more comfortable. However, conventionally, there are limitations to waveguide miniaturization, which in turn limits NED miniaturization.

[0044] Figure 2 A novel waveguide system 20 for NED1 is shown. Figure 2 The first waveguide section 24 of the foldable waveguide system 20 is shown (optically equivalent to...). Figure 1A and Figure 1B The first waveguide section 24 (14) of the waveguide system 10 is configured for ergonomic purposes. The first waveguide section 24 has an aperture 24c through which a beam of light corresponding to an image from the image projector 12 enters the waveguide system 20. In the first waveguide section 24, the beam propagates in a first dimension (e.g., X) and a second dimension (e.g., Z) that is not parallel to (e.g., perpendicular to) the first dimension. The first waveguide section 24 guides the light in the Y dimension by total internal reflection.

[0045] The first portion 24 includes a redirection member 24b (e.g., a folding mirror) at its end, which redirects the light beam to propagate toward a partial reflector 24a in a third dimension (e.g., Y) that is not parallel (e.g., perpendicular) to the first dimension (e.g., X) and the second dimension (e.g., Z). The partial reflector 24a enlarges the aperture in the first dimension (e.g., X) and redirects the light beam toward a partial reflector 26a of the second portion 26. The second waveguide portion 26 receives the light beam and propagates it in the third dimension (e.g., Y). The second waveguide portion 26 guides the light beam in the Z dimension by total internal reflection. A second set of partial reflective surfaces 26a couples the image out in the second dimension (e.g., Z) to enlarge the aperture in the third dimension (e.g., Y).

[0046] In this configuration, the height (Y) of waveguide system 20 is significantly lower than the height (Y) of waveguide system 10, and the triangular shape of the first portion 24 fits the edge of NED1, wherein there is space (in the Z dimension) between waveguide system 20 and the user's face. The angle between the first portion 24 and the second waveguide portion 26 can vary according to ergonomic requirements and optical optimization. Depending on the angle between the first portion 24 and the second waveguide portion 26, reflector 24b can be replaced by a prism. The thicknesses of the first portion 24 and the second waveguide portion 26 can be different. In one embodiment, the first portion 24 is thicker than the second waveguide portion 26, allowing for better illumination of the second waveguide portion 26.

[0047] Figure 3 A novel waveguide system 30 for NED1 is shown. Figure 3 It shows a ratio Figure 2 System 20 has a more compact configuration (in the height Y dimension). In system 30, part of the reflector 34a is located on top of the fold (instead of...). Figure 2 In system 20 (below the fold), the function of this part of the reflector 34a is similar to... Figure 2 Similar to System 20, it is used for beam redirection.

[0048] The first waveguide portion 34 has an aperture 34c through which a light beam corresponding to an image from the image projector 12 enters the waveguide system 30. In the first waveguide portion 34, the light beam propagates in a first dimension (e.g., X) and a second dimension (e.g., Z) that is not parallel to (e.g., perpendicular to) the first dimension. The first waveguide portion 34 guides the light beam in the Y dimension by total internal reflection. The first waveguide portion 34 also has a partial reflector 34a that expands the aperture in the first dimension (e.g., X). The first waveguide portion 34 includes a redirection member 34b (e.g., a folding mirror) at its end, which redirects the light beam to propagate towards the second waveguide portion 36 in a third dimension (e.g., Y) that is not parallel to (e.g., perpendicular to) the first and second dimensions (e.g., Z). The second waveguide portion 36 receives the light beam and propagates it in the third dimension (e.g., Y). The second waveguide portion 36 guides the light beam in the Z dimension by total internal reflection. The second waveguide portion 36 has a partial reflector 36a that couples the image out in the second dimension (e.g., Z) to enlarge the aperture in the third dimension (e.g., Y).

[0049] In this configuration, the height (Y) of the waveguide system 30 is significantly lower than the height (Y) of the waveguide system 10, and the triangular shape of the first portion 34 fits the edge of the NED 1, with a space (in the Z dimension) between the waveguide system 30 and the user's face. The angle between the portion 34 and the portion 36 can vary according to ergonomic requirements and optical optimization. Depending on the angle between the portion 34 and the portion 36, the reflector 34b can be replaced by a prism. The thickness of the guiding portion 34 and the portion 36 can be different from each other. In one embodiment, the first portion 34 is thicker than the second portion 36, so that the portion 36 can be better illuminated.

[0050] In one embodiment, the prism support mirror 34b can have an interface 33a with the HLOE 34 and an interface 33b with the LOE 36. One or both of these interfaces can have a low refractive index with respect to the corresponding waveguide or air gap. This type of interface can reduce losses and improve the coupling between the HLOE 34 and the LOE 36.

[0051] Figure 4 A new waveguide system 40 for the NED 1 is shown. Figure 4 A more compact (in the height Y dimension) configuration than the system 10 of Figure 1 is shown. The HLOE partial reflectors 44a are set at an oblique angle with respect to the waveguide portions 44 and 46. These HLOE partial reflectors 44a are located at the interface between the portions 44 and 46 and serve both to reflect from the waveguide portion 44 to the waveguide portion 46 and to partially transmit (partially reflect) the light beam to achieve lateral (in the X dimension) expansion. Thus, the here oblique HLOE facets 44a serve to perform both functions simultaneously as performed by the partial reflectors 24a, 34a and the reflecting means 24b, 34b in Figures 2 and 3, respectively. Figure 2 and Figure 3

[0052] ​The first waveguide section 44 has an aperture 44c through which the light beams corresponding to the image from the image projector 12 enter the waveguide system 40. In the first waveguide section 44, the light beams propagate in a first dimension (e.g., X) and a second dimension (e.g., Z) that is not parallel (e.g., perpendicular) to the first dimension. The first waveguide section 44 guides the light rays in the Y dimension by total internal reflection. The partial reflector 44a expands the aperture in the first dimension (e.g., the X dimension). The partial reflector 44a also redirects the light beams to propagate in a third dimension (e.g., Y) that is not parallel (e.g., perpendicular) to the first dimension (e.g., X) and the second dimension (e.g., Z) toward the second waveguide section 46. The second waveguide section 46 receives the light beams and propagates the light beams in the third dimension (e.g., Y). The second waveguide section 46 guides the light beams in the Z dimension by total internal reflection. The second waveguide section 46 has a partial reflector 46a that couples out the image in the second dimension (e.g., Z) to expand the aperture in the third dimension (e.g., Y).

[0053] In this configuration, the height (Y) of the waveguide system 40 is significantly lower than the height (Y) of the waveguide system 10, and the triangular shape of the first section 44 fits the edge of the NED 1 where there is space (in the Z dimension) between the waveguide system 40 and the user’s face. The angle of the facet 44a can vary according to ergonomic requirements and optical optimization. The thickness of the guide section 44 and section 46 can be different from each other. In one implementation, the first section 44 is thicker than the second section 46, and thus can better illuminate the section 46.

[0054] Figure 5 A waveguide system 50 is shown for two-dimensional aperture expansion in a ID waveguide. Here three light beams are tracked: the solid arrow represents the center of the field, the dashed arrow represents the ray on one edge of the field, and the dotted arrow represents the ray on the opposite edge of the field. All field rays can be injected into the waveguide system 50 through a single narrow pupil or aperture 54c. Thus, the aperture of the projector 12 (not shown) on this plane can have a relatively small aperture corresponding to the aperture 54c. As the light beams propagate in the HLOE 54, some light is reflected by the facet 54a down toward the LOE 56 and its facet 56a. The reflected light of the first edge (dotted line) is reflected at 54aa near the aperture 54c, while the center (solid arrow) light ray is reflected at 54ab, and the reflected light of the other image edge (dashed line) is reflected at 54ac.

[0055] A potential problem with this arrangement is that it requires a relatively large HLOE section 54 (with facet 54a), which is not ergonomic for use in NED implementations.

[0056] Figure 6AAn alternative waveguide system 60a is shown, in which the beam does not resemble... Figure 5 Unlike system 50, which enters the waveguide from the same point, in this configuration, the side image beams both enter the waveguide from point 12a, while the center image beam enters from point 12b. Therefore, the projector aperture 64c is wider to project all beams and generate a complete image. In this configuration, the HLOE facet 64a reflects the beams, but from different points 64aa, 64ab, and 64ac. This new arrangement of reflection points allows for a smaller HLOE 64 layout, which is ergonomically acceptable for NED implementation.

[0057] Waveguide system 60a includes a first waveguide portion 64 and a second waveguide portion 66. Although the first waveguide portion 64 and the second waveguide portion 66 are referred to as different waveguide portions in this disclosure, these waveguide portions can be implemented as part of a single waveguide or waveguide assembly. See, for example, [link to relevant documentation]. Figure 11C .

[0058] The first waveguide section 64 has an aperture 64c through which a beam of light corresponding to an image from an image projector (not shown) enters the waveguide system 60a.

[0059] The first waveguide portion 64 includes a first set of at least partially reflective surfaces 64a. The first set of at least partially reflective surfaces 64a couples light corresponding to the image out of the first waveguide portion 64, thereby enlarging the aperture in a first dimension (e.g., X).

[0060] The second waveguide portion 66 receives light from the first waveguide portion 64 and includes a second set of partially reflective surfaces 66a that couple out light corresponding to the image, thereby enlarging the aperture in a second dimension (e.g., Y) that is not parallel (e.g., perpendicular) to the first dimension (e.g., X).

[0061] like Figure 6A As shown, the first extreme beam (corresponding to pixels at the image edge) is at least partially reflected by the first extreme at least partially reflective surface 64aa. The second extreme beam (corresponding to pixels on opposite edges of the image) is at least partially reflected by the second extreme at least partially reflective surface 64ac, which is disposed at opposite ends of the waveguide portion 64. The center beam (corresponding to pixels at the image center) is at least partially reflected by a third at least partially reflective surface 64ab, which is disposed between the first at least partially reflective surface 64aa and the second extreme at least partially reflective surface 64ab. The first set of at least partially reflective surfaces 64aa couples the light corresponding to the image out of the first waveguide portion 64 towards the second waveguide portion 66.

[0062] Facet portion 64g shows that the spacing between facets 64a can vary along HLOE 64 according to the corresponding illumination aperture. The larger the aperture 64c, the larger the spacing required between facets 64a.

[0063] Figure 6B An alternative waveguide system 60b is shown, which corresponds to system 60a of Figure 6A but in which the input image light from projector 12 is coupled into a primary waveguide 68. Waveguide 68, which can be a two-fold or three-fold light guide, performs a primary aperture expansion to fit the expanded width of aperture 64c of HLOE 64. Primary waveguide 68 has an internal partially reflective facet 68a that receives the image light from projector 12 and performs a primary aperture expansion to fit the width of aperture 64c.

[0064] Partially reflective surface 68a of waveguide 68 can be designed so that the aperture illumination illuminating portions of HLOE 64 can vary by portion. For example, the illumination from the edges (64ad or 64ae) can have a smaller aperture illumination compared to the central portion of aperture 64c. Furthermore, the spacing between facets 64a can vary along HLOE 64 according to the local aperture illumination. The larger the aperture illumination, the larger the spacing required between corresponding facets 64a.

[0065] Figure 6C A configuration 60c is shown that corresponds to 60a in Figure 6A but in which two adjacent projectors 201a and 201b project the image in two parts, rather than one part as shown in 60a. The two side-by-side projectors 201a and 201b produce an actual expanded projector aperture (corresponding to aperture 64c in waveguide system 60a) in which the aperture of each projector is fully illuminated, and each projector illuminates a different image area and a different portion of waveguide 66. Projector 201a projects a light beam 203 that is reflected to a light beam 205 on one side of waveguide portion 66. The same projector 201a projects light beams 207a (and intermediate beams, not shown for clarity) that are reflected in waveguide portion 64 to a light beam 209 at the center of the field.

[0066] Projector 201b projects a light beam 211 that is reflected to a light beam 213, and projector 201b projects light beams 207b (parallel to light beams 207a) that are reflected to light beam 209, overlapping light beam 209 with light beam 207a from projector 201a. Projector 201b also projects light beams between light beam 209 and light beam 213, projecting the other half of the field with some overlap with projector 201a.

[0067] The facets of waveguide sections 64 and / or 66 of the above configuration can be replaced with diffraction gratings of approximately the same orientation. The expanded input aperture (same as above) can include an input coupling to a reflector, prism or diffractive element.

[0068] As Figure 6C illustrated, the use of two or more projectors 201a, 201b enables the use of small projectors of uniform illumination that are easy to produce, while benefiting from a large aperture with a small waveguide section 64. If multiple projectors are not desired, a Figure 6A new type of projector can be required for the light distribution illustrated.

[0069] Figure 7 A schematic diagram of an exemplary projector 72 designed to control the light beam distribution at the projector aperture 73 is shown. The exemplary projector 72 produces a light beam distribution corresponding to the aperture 64c of Figure 6A , where the side image beams enter the waveguide from point 12a, while the center image beams enter the waveguide from point 12b. In Figure 7 , the notation of the light beams is the same as in Figure 6A : the solid lines represent the center field, while the dashed lines represent the field edges.

[0070] The image projector 72 can include a projector aperture 73 corresponding to the aperture 64c of the first waveguide section 64. The image projector 72 can also include an image generator matrix 74, such as a Micro-LED, OLED, front-illuminated LCOS, DLP, LCD, etc., illuminated by a light source 78, such as an LED, laser or scanning laser. The matrix 74 can generate an image to be projected, projecting a light beam for each pixel. The image projector 72 can also include a collimating lens 76 that receives and collimates the light corresponding to the image generated by the matrix 74. The image projector 72 can also include a phase element 75 disposed relative to the matrix 74 and the collimating lens 76 to control the light beam distribution at the projector aperture 73. In Figure 7 , the phase element 75 is disposed between the matrix 74 and the collimating lens 76 to control the light beam distribution at the projector aperture 73.

[0071] The phase element 75 can be a transparent wafer on which a relief pattern is formed, or can be a diffractive optical element through which one or more light beams pass. The profile of the phase element 75 is defined to produce the desired light beam distribution. One or more light beams corresponding to the center field of the image generated by the matrix 74 exit the projector aperture 73 at the edges of the projector aperture 73, while one or more light beams corresponding to the edge field of the image generated by the matrix 74 exit the projector aperture 73 at the center of the projector aperture 73. In this way, the Figure 6AIn this case, the side image beam enters the waveguide from point 12a, while the center image beam enters the waveguide from point 12b on aperture 64c.

[0072] In a preferred embodiment, the phase element 75 is positioned very close to the matrix 74 to prevent image distortion. The lens 76 collimates the beam emitted by the phase element 75 onto the aperture 73.

[0073] Figure 8A A schematic diagram of another exemplary projector 82a is shown, which is designed to control the beam distribution at the projector aperture 73. The exemplary projector 82a produces... Figure 6A The beam distribution corresponding to aperture 64c, where the side image beam enters the waveguide from point 12a, and the center image beam enters the waveguide from point 12b. Figure 8A In the middle, the markings of the beam and Figure 6A Similarities: Solid lines represent the center field, and dashed lines represent the edge of the field.

[0074] The image projector 82a may include a projector aperture 73 corresponding to the aperture 64c of the first waveguide portion 64. The image projector 82a may also include an image generation matrix 74 illuminated by a light source 78. The matrix 74 can generate an image to be projected, projecting a beam of light for each pixel. The image projector 82a may also include a collimating lens 76 for receiving and collimating the light corresponding to the image generated by the matrix 74. Figure 8A In this configuration, the collimating lens 76 is optically positioned between the projector aperture 73 and the matrix 74. The image projector 72 may also include a phase element 75, which is positioned relative to the matrix 74 and the collimating lens 76 to control the beam distribution at the projector aperture 73. Figure 8A In this configuration, phase element 75 is optically positioned between light source 78 and matrix 74 to control the beam distribution at projector aperture 73. Image projector 72 may also include optics 86a, which is optically positioned between light source 78 and phase element 75 to optimize optical power coupling at projector aperture 73 while minimizing the optical power required by phase element 75.

[0075] exist Figure 8A In this configuration, the phase element 75 is optically positioned between and close to the light source 78 and the matrix 74. This arrangement can be applied to a transparent LCD matrix 74 or an LCOS, where the phase element 75 can be a unidirectional effective diffuser, such as a polarization selective diffuser. In other embodiments, the phase element 75 can be positioned on the opposite side of the matrix 74, or separated between the two sides of the matrix 74 (it can also be used as a simple phase element adjacent to the LCOS, effective both before and after reflection).

[0076] Figure 8BA schematic diagram of another example projector 82b that corresponds to the projector 82a of Figure 8A but uses LCOS technology and a polarizing beam splitter (PBS) 81 is shown. Here, the phase element 75 is traversed twice before and after being reflected by the LCOS matrix 74, so the phase of a single traversal is half of the desired phase.

[0077] The projector 82b includes a projector aperture 73 that corresponds to the aperture 64c of the first waveguide portion 64 of Figure 6A The projector 82b also includes a light source 78 and a LCOS matrix 74 that is optically between the projector aperture 73 and the light source 78. The matrix 74 receives light from the light source 78 and generates an image to be projected. The projector 82b also includes a phase element 75 that is optically between the light source 78 and the matrix 74 to control the light beam distribution at the projector aperture 73. The projector 82b also includes a PBS 81 that is optically between the light source 78 and the projector aperture 73. The PBS 81 reflects light of a first polarity from the light source 78 through the phase element 75 to the matrix 74. The matrix 74 changes the polarity of the light. The PBS 81 reflects light of a second polarity from the matrix 74 through the phase element 75 to a polarizing reflector 87, which again changes the polarity of the light. The light of the first polarity is reflected from the polarizing reflector 87 to the projector aperture 73. The projector 82b also includes optics 86c that are optically between the light source 78 and the phase element 75 to optimize the light power coupling at the projector aperture 73 while minimizing the light power required by the phase element 75.

[0078] Figure 9A A schematic diagram of another example projector 92a that is designed to control the light beam distribution at the projector aperture 73 is shown. The example projector 92a produces a light beam distribution that corresponds to the aperture 64c of Figure 6A where the side image beams enter the waveguide from point 12a and the center image beams enter the waveguide from point 12b. In Figure 9A the notation of the light beams is the same as in Figure 6A The projector 92a is an extended configuration that is needed when it is impractical to implement the phase element 75 next to the matrix 74. In this case, the phase element 75 is conjugate to the matrix 74 plane and the light source 78 is conjugate to the aperture 73.

[0079] As with the previous projectors, here the light source 78 illuminates the phase element 75 via optics 86a and the phase element 75 is imaged onto the matrix 74 via optics 86b. The image projector 92a can also include a collimating lens 76 that receives and collimates light corresponding to the image produced by the matrix 74 and transmits the collimated light to the aperture 73.

[0080] The projector 92a can include a projector aperture 73 corresponding to the aperture 64c of the first waveguide portion 64. The projector 92a can also include a light source 78 and a matrix 74 optically disposed between the projector aperture 73 and the light source 78. The matrix 74 receives light from the light source 78 and generates an image to be projected. The projector 92a can also include a collimating lens 76 optically disposed between the projector aperture 73 and the matrix 74. The lens 76 can receive and collimate light corresponding to the image generated by the matrix 74. The projector 92a can also include a phase element 75 optically disposed between the light source 78 and the matrix 74 to control the beam distribution at the projector aperture 73. The projector 92a can also include optics 86a and 86b optically disposed between the light source 78 and the phase element 75 and between the phase element 75 and the matrix 74, respectively. The optics 86a and 86b optimize the optical power coupling at the projector aperture 73 while minimizing the optical power required by the phase element 75.

[0081] Figure 9B A schematic diagram of another exemplary projector 92b corresponding to the projector 92a of FIG. 1A but using LCOS technology and a polarizing beam splitter (PBS) 81 is shown. The phase element 75 is traversed twice before and after being reflected by the LCOS matrix 74, so the phase of a single traversal is half of the required phase. Figure 9A

[0082] The projector 92b can include a projector aperture 73 corresponding to the aperture 64c of the first waveguide portion 64, a light source 78, and a matrix 74 optically disposed between the projector aperture 73 and the light source 78. The matrix 74 receives light from the light source 78 and generates an image to be projected. The projector 92a can also include a phase element 75 optically disposed between the light source 78 and the matrix 74 to control the beam distribution at the projector aperture 73. The projector 92a can also include a PBS 81 optically disposed between the light source 78 and the projector aperture 73 to reflect light of a first polarization from the light source 78 through the phase element 75 to the matrix 74, reflect light of a second polarization from the matrix 74 to a polarizing reflector 87, and reflect light of the first polarization from the polarizing reflector 87 to the projector aperture 73. The projector 92a can also include optics 87a optically disposed between the light source 78 and the phase element 75 and optics 87b optically disposed between the phase element 75 and the matrix 74 to optimize the optical power coupling of the projector aperture 73 while minimizing the optical power required by the phase element 75.

[0083] ​Alternatively, each reflective pixel element on the LCOS is produced with a tilt appropriate to the local phase required. For example, if the reflected beam from one pixel in the LCOS needs to exit from one side of the aperture, the reflective element for that pixel will be produced with a tilt within the LCOS. On the other hand, if the beam needs to exit from the center of the aperture, the reflective element within the LCOS matrix can be flat.

[0084] Figure 10A A schematic diagram of another example projector 102a designed to control the light beam distribution at the projector aperture 73 is shown. The example projector 102a produces a light beam distribution corresponding to the aperture 64c of Figure 6A where the side image beams enter the waveguide from point 12a and the center image beams enter the waveguide from point 12b. In Figure 10A the labeling of the light beams is the same as in Figure 6A the center field is represented by a solid line and the field edges are represented by dashed lines. In the projector 102a, each reflective pixel element on the LCOS matrix 74a is produced with a tilt appropriate to the local phase required. For example, if the reflected beam from one pixel in the LCOS matrix 74a needs to exit from one side of the aperture 73, the reflective element for that pixel will be produced with a tilt within the LCOS matrix 74a in the direction indicated by arrow 74c. On the other hand, if the beam needs to exit from the center of the aperture 73, the reflective element within the LCOS matrix 74a will be flat.

[0085] The projector 102a can include a projector aperture 73 corresponding to the aperture 64c of the first waveguide portion 64, a light source 78, and an LCOS matrix 74a optically disposed between the projector aperture 73 and the light source 78. The matrix 74a receives light from the light source 78 and generates an image to be projected. Each reflective pixel element on the matrix 74a is disposed with a corresponding tilt (in the direction indicated by arrow 74c) to control the light beam distribution at the projector aperture 73.

[0086] "Tilt" in this context refers to a change in orientation of the liquid crystal molecules in the LCOS matrix that is used to adjust the polarization of the reflected light. By adjusting the electric field applied to each pixel, the light intensity of each pixel can be modulated. This controls which pixels are bright and which are dark, managing the light pattern that forms the image, effectively setting each reflective pixel element with a corresponding tilt to control the light beam distribution at the projector aperture 73. Thus, the light distribution at the projector aperture 73 can be controlled by manipulating the polarization of the light reflected from each pixel at the matrix 74a. The lens 76 can receive and collimate the light corresponding to the image generated by the matrix 74a.

[0087] Each reflective pixel element on the matrix 74a can be set to a respective tilt such that one or more light beams corresponding to a central field of the image exit the projector aperture 73 at an edge of the projector aperture 73. Similarly, each reflective pixel element on the matrix 74a can be set to a respective tilt such that one or more light beams corresponding to an edge field of the image exit the projector aperture 73 at a central location of the projector aperture 73.

[0088] Figure 10B A schematic diagram of another example projector 102b corresponding to the projector 102a of Figure 10A but using a polarizing beam splitter (PBS) 81 is shown. The example projector 102b produces a light beam distribution corresponding to the aperture 64c of the Figure 6A with the side image beams entering the waveguide from point 12a and the central image beams entering the waveguide from point 12b. In the projector 102b, each reflective pixel element on the LCOS matrix 74a is produced with a tilt appropriate to the local phase required. If the reflected light beam of one pixel in the LCOS matrix 74a needs to exit from one side of the aperture 73, then the reflective element of that pixel within the LCOS matrix 74a will be produced. On the other hand, if the light beam needs to emerge from the center of the aperture 73, then the reflective element within the LCOS matrix 74a will be flat.

[0089] The projector 102b can include a projector aperture 73 corresponding to the aperture 64c of the first waveguide portion 64, a light source 78, and a matrix 74a optically disposed between the projector aperture 73 and the light source 78. The matrix 74a receives light from the light source 78 and generates an image to be projected. The projector 102b also includes a PBS 81 optically disposed between the light source 78 and the projector aperture 73 to reflect light of a first polarization from the light source 78 to the matrix 74a, to reflect light of a second polarization from the matrix 74a to a polarizing reflector 87, and to reflect light of the first polarization from the polarizing reflector 87 to the projector aperture 73. A lens 76 can receive and collimate light corresponding to the image generated by the matrix 74a.

[0090] Each reflective pixel element on the matrix 74a can be set to a respective tilt such that one or more light beams corresponding to a central field of the image exit the projector aperture 73 at an edge of the projector aperture 73. Similarly, each reflective pixel element on the matrix 74a can be set to a respective tilt such that one or more light beams corresponding to an edge field of the image exit the projector aperture 73 at a central location of the projector aperture 73.

[0091] Facets (e.g. Figure 5The coating of the facets 54a in the waveguide 54 can have a polarization selectivity in which S-polarization is partially reflected and P-polarization is mostly transmitted. It can therefore be beneficial to introduce a waveplate between the waveguide 54 and the waveguide 56 so that the light beams impinge on the facets 54a with S-polarization. However, a waveplate at this location between the waveguide 54 and the waveguide 56 is likely to be seen by the user and introduce unwanted reflections, degrading the quality of the projected image.

[0092] Figures 11A, 11B and Figure 11C An alternative waveguide system 110 is shown, which is similar to the system 50 of Figure 5 but modified so that the waveplate 112 is located at the edge of the waveguide system 110, preventing unwanted reflections. The waveguide system 110 also includes a reflective surface (e.g. mirror) 114 to reflect light back to the LOE 56 through the HLOE 54. As in the system 50 of Figure 5 As in the system 50 of

[0093] While only the light beam 118 is discussed in detail here, all the light beams follow the same optical processes in relation to the waveplate 112 and the reflective surface 114. The light beam 118a is coupled into the system 110 through the aperture 54c and propagates along the waveguide section 54. At this stage, the light beam 118 is S-polarized. The light beam 118a impinges on the facet 54ac (in this example, the last facet in the waveguide section 54 is important), which is arranged at an angle to reflect the light beam 118a out of the facet 54ac towards the waveplate 112 and the reflective surface 114 as the light beam 118b. That is, the facet 54ac (and the rest of the facets 54a) is arranged at an angle to reflect light in the opposite direction to the facets in the system 50 of Figure 5

[0094] In Figure 11B, the circle dot represents S-polarization, the curved arrow represents circular polarization, and the double arrow represents P-polarization. The light beam 118b reaches the quarter-wave plate 112, which changes the polarization of the light beam from S-polarization to circular polarization. The light beam 118b is circularly polarized after passing through the quarter-wave plate 112 and is then reflected back towards the waveguide section 54 from the reflective surface 114 (e.g. a dielectric mirror or a metallic mirror). The reflected light beam 118c passes through the quarter-wave plate (e.g. retarder) 112 again, now as a P-polarized light beam 118c.

[0095] ​P-polarized beam 118c passes through waveguide portion 54 with minimal reflection and impinges on facet 56a of waveguide portion 56. When reflected by facet 56a, the polarization of beam 118c is S-polarized, so the output reflection is optimal.

[0096] As Figure 11C shown (perspective view of system 110), reflector 114 and waveplate 112 are placed close to the edges of system 110 so that the visibility of these elements is minimized. For example, these elements 112 and 114 (placed at the edges of the square shown in Figure 11C may be disposed in frame 18 of NED 1 to conceal or hide elements 112 and 114 in frame 18.

[0097] Thus, waveguide system 110 can include a first waveguide portion 54 having an aperture 54c through which a beam of light corresponding to an image from image projector 12 enters waveguide system 110. First waveguide portion 54 includes a first set of at least partially reflective surfaces 54a. First set of at least partially reflective surfaces 54a couples light corresponding to an image out of first waveguide portion 54 away from second waveguide portion 56 toward reflector 114 and / or waveplate 112, thereby expanding the aperture in a first dimension (e.g., X).

[0098] Waveguide system 110 can also include a second waveguide portion 56 that receives light from first waveguide portion 54 and includes a second set of partially reflective surfaces 56a to couple out light corresponding to an image, thereby expanding the aperture in a second dimension (e.g., Y) that is not parallel (e.g., perpendicular) to the first dimension (e.g., X).

[0099] Waveguide system 110 can also include a quarter wave plate 112 and one or more reflectors 114 disposed on a side of first waveguide portion 54 opposite the side on which second waveguide portion 56 is disposed, such that: (1) first set of at least partially reflective surfaces 54a couples light corresponding to an image out of first waveguide portion 54 toward quarter wave plate 112 and one or more reflectors 114 (2) quarter wave plate 112 rotates the polarization of the light by a quarter wave; (3) one or more reflectors 114 reflect the light back through quarter wave plate 112; (4) quarter wave plate 112 rotates the polarization of the light by another quarter wave to be, for example, P-polarized; and (5) the light travels through first waveguide portion 54 toward second waveguide portion 56.

[0100] FIG. 12A and system 120 corresponds to system 110 of FIG. 11A, but is modified to include at least one modified partial reflector (also referred to as a “homogenizer”) 116. FIG. 12B shows a first alternative magnified view. In the embodiment of FIG. 12B, system 120 includes a partial reflecting surface 116. In the embodiment of FIG. 12C, system 120 includes two partial reflecting surfaces, partial reflecting surface 116a and partial reflecting surface 116b. By using a partial reflecting surface 116 or partial reflecting surface 116a, partial reflecting surface 116b, a more uniform illumination of waveguide system 120 (as compared to system 110) can be achieved with a smaller spacing between the first partial reflector (partial reflecting surface 116 or partial reflecting surface 116a) and reflecting surface 114. As shown, implementing one or more partial reflectors 116 in waveguide system 120 results in multiple beams, making the output image more uniform. In FIG. 12B and FIG. 12C, partial reflector 116 or partial reflector 116a, partial reflector 116b is disposed between waveplate 112 and reflector 114.

[0101] FIG. 12B shows the reflection of one of the beams, while the other beams undergo the same optical process. The impinging beam (S-polarized) is converted to circular polarization after passing through waveplate 112. When this beam impinges on partial reflector 116, a portion is reflected, and a portion is transmitted to be reflected by reflecting surface 114. Multiple reflections continue to produce more beams with decreasing intensity. All of these beams are reflected back through waveplate 112 and exit as P-polarized toward facet 56a.

[0102] In some configurations, there is no waveplate, and only reflecting surface 114 is present. In some configurations, there is only partial reflector 116 and reflector 114. In all of the above configurations, HLOE 54 can be located to the side or below LOE facet 56a. Facet 56a can be oriented accordingly (relative to HLOE 54) to couple out the beams from waveguide portion 56. In some configurations, partial reflector 116 can be located in the optical path before waveplate 112, so some reflections are P-polarized, and some are S-polarized, resulting in beams that are virtually unpolarized. The reflectivity of partial reflector 116 needs to be numerically optimized to achieve maximum and uniform power output from system 120.

[0103] Figure 13A System 120 corresponding to the configuration of FIG. 12A is shown. Figure 13A A nominal image beam path is shown. Figure 13BAn undesired beam path (ghost) is shown in another aspect. Here, beam 118 transmits through the facets of HLOE 54, is first reflected at reflection point R by reflective surface 114 and partial reflector 116, then reflected by the facets of HLOE 54, and continues to be reflected by the facets of LOE 56 as the nominal beam, ultimately producing an unwanted "ghost" image. The "ghost" beam has a larger angle of reflection at reflection point R than the nominal reflection (e.g. Figure 13A shown in FIG. 1 IB) with respect to reflectors 114 and 116. Accordingly, an angle-selective dielectric coating (as shown in FIG. 1 IC) can be designed on reflectors 114 and 116. The dielectric coating is designed such that the desired reflectivity (preferably for both polarizations) is achieved for angles of incidence from zero to twenty degrees, while high angles such as sixty to eighty degrees are not reflected by reflectors 114 and 116 (i.e., are instead transmitted). As shown in FIG. 1 ID, system 120 can include a light absorber 119 to absorb any light transmitted by reflector 114 (i.e., the "ghost"). Figure 13C Figure 13B As shown in FIG. 1 ID, system 120 can include a light absorber 119 to absorb any light transmitted by reflector 114 (i.e., the "ghost").

[0104] FIGS. 14A, 14B, and 14C illustrate an example production process for constructing system 120 shown in FIG. 12A. FIG. 14A shows a stack 140 including a reflector plate 142, an HLOE stack 144, and an LOE stack 146.

[0105] Reflector plate 142 can include top (stacked) reflector 114, waveplate 112, and partial reflector 116 at the bottom of reflector plate 142. As previously mentioned, these components can have a different order.

[0106] HLOE stack 144 includes HLOE 54 and a transparent portion 145. HLOE stack 144 is produced by stacking partial reflectors (stacked plates with partial reflective coatings) and slicing the resulting structure into the shape shown in FIG. 14A. The HLOE 54 facets can be perpendicular to the outside of the waveguide, or can be tilted with respect to the outside. A transparent portion 145 is added on top so that the upper surface of HLOE stack 144 is parallel to its lower surface. LOE stack 146 is made from stacked plates with partial reflective coatings. LOE stack 146 is sliced into the shape shown.

[0107] FIG. 14B shows the combined stack (reflector plate 142, HLOE stack 144, LOE stack 146). The combined stack 140 is sliced in a parallel plane that is perpendicular to the facets of LOE 56 and parallel to reflective surface 114 and reflective surface 116 of sliced reflector plate 143.

[0108] ​As shown in FIG. 14C, the generated slice corresponds to system 120 of FIG. 12A. Thus, system 120 can include a plate 143 that includes quarter-wave plate 112, one or more partially reflective surfaces 116, and one or more reflectors 114. Plate 143 can be disposed on the side of first waveguide portion (HLOE) 54 opposite second waveguide portion 56, such that: (1) first set of at least partially reflective surfaces 54a couple light corresponding to an image out of first waveguide portion 54 toward plate 143; (2) quarter-wave plate 112 rotates the polarization of the light by a quarter-wave; (3) one or more partially reflective surfaces 116 partially transmit and partially reflect the light; (4) one or more reflectors 114 reflect the transmitted light back through one or more partially reflective surfaces 116 and quarter-wave plate 112; (5) one or more partially reflective surfaces 116 partially transmit and partially reflect the light; (6) quarter-wave plate 112 rotates the polarization of the light by another quarter-wave; and (7) the light travels through first waveguide portion 54 toward second waveguide portion 56.

[0109] Figure 15 A waveguide system 150 similar to system 120 is shown, but here the reflective surface 114 (and / or plate 143) is split into parallel reflective surfaces 114a-e. Splitting of reflective surface 114 makes the back reflections 118b shorter (compared to reflections 118b in FIG. 12A), thus allowing HLOE 54 to be shorter. Furthermore, this arrangement makes NED frame 18 approximately circular, more ergonomic, and perhaps more aesthetically pleasing. By ensuring that the spacing between HLOE facets 54a is small, the effects of discontinuities between reflective surfaces 114a-e can be prevented from being projected onto the image. In addition to reflective surfaces 114a-e, quarter plate 112, partially reflective 116, and light absorber 119 can also be split along the same segments as shown in FIG. 14D. Figure 15

[0110] ​FIGS. 16A, 16B, and 16C show a waveguide system 160 that combines features of system 60a of FIG. 6 and system 120 of FIG. 12A. System 160 is an implementation of a combination of an inverted facet 164a and reflective surface 114 (comparable to facet 54a and reflective surface 114 of system 120) with a distributed / large aperture 164c (comparable to aperture 64c of system 60a). In this configuration, the position of the light beam in aperture 164c is different (mostly opposite in the vertical direction) compared to the position of the light beam in aperture 64c, but the result is the same. By combining an inverted facet 164a and reflective surface 114 with a distributed / large aperture 164c, the width of the HLOE portion 164 can be narrower (facet 164a compared to facet 54a). In addition, the length of the HLOE 54 can be shortened because the reflective pass 118b at the edge of the field is much shorter.

[0111] Thus, compact waveguide system 160 can be used to produce a smaller NED.

[0112] Definitions

[0113] The following includes definitions of selected terms employed herein. The definitions include various examples or forms of components that fall within the scope of a term and that can be used in implementations. Not all the examples are intended to be limiting in nature. Both singular and plural forms of terms can be within the definitions.

[0114] An“operable connection,” or connection by which entities are“operably connected,” is one which allows signals, physical communications or logical communications between entities. Typically, an operable connection includes a physical interface, an electrical interface, or a data interface, but it is to be noted that an operable connection can include differing combinations of these or other types of interfaces as would be recognized by those skilled in the art. For example, two entities can be operably connected by the ability to exchange signals, whether electronically, physically or otherwise, directly or through one or more intermediate entities (e.g., a processor, operating system, logic, software, or other entity). Logical or physical communication channels can be used to create an operable connection.

[0115] Whenever a term is used in the specification or claims—such as "includes" or "including"—it is intended to be inclusive of that which is illustrated in the specification or claims and also of equivalents. In addition, whenever a term is used in the specification or claims—such as "or"—such term is intended to mean "either" of the items so conjoined. When an applicant intends "only A or B, but not both," then the applicant will employ the term "only A or B but not both." Thus, the use of the term "or" in this specification and claims is an inclusive use of the term. See Bryan A. Garner, A Dictionary of Modern Legal Usage 624 (2d Ed. 1995).

[0116] While example systems, methods, and so on have been illustrated by describing examples, and while these examples have been quite detailed, the intent is not to limit or restrict the scope of the example to the specific details of the examples. Many additional advantages and modifications will readily occur to those skilled in the art. The application in its broader aspects is therefore not limited to the specific details, representative apparatus, and illustrative examples shown and described. Accordingly, departures can be made from such details without departing from the scope of the general inventive concept. Moreover, the preceding description is not intended to limit the scope of the application. Rather, the scope of the application is defined by the appended claims and their equivalents.

Claims

1. A waveguide system for a near-eye display, comprising: a first waveguide portion having an aperture through which a light beam corresponding to an image from an image projector enters the waveguide system, wherein the first waveguide portion includes one or more first optical elements configured to couple light corresponding to the image out of the first waveguide portion to expand the aperture in a first dimension; and a second waveguide portion disposed on a first side of the first waveguide portion and configured to receive light from the first waveguide portion, and the second waveguide portion includes one or more second optical elements configured to couple out light corresponding to the image to expand the aperture in a second dimension that is not parallel to the first dimension; one or more reflectors disposed on a second side of the first waveguide portion opposite the first side, wherein: (1) the one or more first optical elements couple light corresponding to the image out of the first waveguide portion toward the one or more reflectors; and (2) the one or more reflectors reflect light corresponding to the image back through the first waveguide portion toward the second waveguide portion.

2. The waveguide system of claim 1, wherein, the one or more first optical elements correspond to a first set of parallel partially-reflecting surfaces or to a first diffractive grating, and the one or more second optical elements correspond to a second set of parallel partially-reflecting surfaces or to a second diffractive grating.

3. The waveguide system of claim 1, the waveguide system includes: a plate including a quarter-wave plate and the one or more reflectors, the plate disposed such that: (1) the one or more first optical elements couple light corresponding to the image out of the first waveguide portion toward the plate; (2) the quarter-wave plate rotates polarization of the light by a quarter-wave; (3) the one or more reflectors reflect the transmitted light back through the quarter-wave plate; (4) the quarter-wave plate rotates polarization of the light by another quarter-wave; and (5) the light travels through the first waveguide portion toward the second waveguide portion.

4. The waveguide system of claim 1, wherein, The one or more first optical elements correspond to a first set of at least partially reflective surfaces and the one or more second optical elements correspond to a second set of at least partially reflective surfaces, wherein: (1) a first extreme beam from the light beam is at least partially reflected by a first extreme at least partially reflective surface from the first set of at least partially reflective surfaces; (2) a second extreme beam from the light beam opposite the first extreme beam is at least partially reflected by a second extreme at least partially reflective surface from the first set of at least partially reflective surfaces, the second extreme at least partially reflective surface being opposite the first extreme at least partially reflective surface from the first set of at least partially reflective surfaces; and (3) a central beam from the light beam is at least partially reflected by a third at least partially reflective surface from the first set of at least partially reflective surfaces disposed between the first extreme at least partially reflective surface and the second extreme at least partially reflective surface.

5. The waveguide system of claim 1, comprising: a quarter-wave plate optically disposed between the first waveguide portion and the one or more reflectors such that: (1) the one or more first optical elements couple light corresponding to the image out of the first waveguide portion toward the quarter-wave plate and the one or more reflectors; (2) the quarter-wave plate rotates a polarization of the light by a quarter-wave; (3) the one or more reflectors reflect the light back through the quarter-wave plate; (4) the quarter-wave plate rotates the polarization of the light by another quarter-wave; and (5) the light travels through the first waveguide portion toward the second waveguide portion.

6. The waveguide system of claim 1, comprising: a plate comprising a quarter-wave plate, one or more partially reflective surfaces, and the one or more reflectors, the plate disposed such that: (1) the one or more first optical elements couple light corresponding to the image out of the first waveguide portion toward the plate; (2) the quarter-wave plate rotates a polarization of the light by a quarter-wave; (3) the one or more partially reflective surfaces partially transmit and partially reflect the light; (4) the one or more reflectors reflect the transmitted light back through the one or more partially reflective surfaces and the quarter-wave plate; (5) the one or more partially reflective surfaces partially transmit and partially reflect the reflected light; (6) the quarter-wave plate rotates the polarization of the light by another quarter-wave; and (7) the light travels through the first waveguide portion toward the second waveguide portion.

7. The waveguide system of claim 1, comprising: one or more partially-reflective surfaces optically disposed between the first waveguide portion and the one or more reflectors such that: (1) the one or more first optical elements couple light corresponding to the image out of the first waveguide portion through the second major surface and the third major surface toward the one or more partially-reflective surfaces and the one or more reflectors; (2) the one or more partially-reflective surfaces partially transmit and partially reflect the light; (3) the one or more reflectors reflect the transmitted light back through the one or more partially-reflective surfaces; (4) the one or more partially-reflective surfaces partially transmit and partially reflect the reflected light, and (5) the transmitted light travels through the first waveguide portion toward the second waveguide portion.

8. A waveguide system for a near-eye display, comprising: a first waveguide portion having: an aperture through which a light beam corresponding to an image from an image projector enters the waveguide system; a first major surface and a second major surface between which the light beam is guided by total internal reflection; and a first set of at least partially-reflective surfaces configured to couple light corresponding to the image out of the first waveguide portion to expand the aperture in a first dimension; and a second waveguide portion configured to receive light from the first waveguide portion and comprising: a first major surface and a second major surface between which the light is guided by total internal reflection; and a second set of at least partially-reflective surfaces configured to couple out light corresponding to the image to enlarge the aperture in a second dimension non-parallel to the first dimension, wherein the first waveguide portion is configured such that one or more light beams corresponding to a first edge field of the image enter the waveguide system through the aperture at a first edge of the aperture, one or more light beams corresponding to a second edge field of the image enter the waveguide system through the aperture at the first edge of the aperture, and one or more light beams corresponding to a center field of the image enter the waveguide system through the aperture at a second edge of the aperture opposite the first edge.

9. The waveguide system of claim 8, wherein, The first waveguide portion is configured such that: one or more beams corresponding to a first edge field of the image are at least partially reflected by a first extreme at least partially reflecting surface from the first set of at least partially reflecting surfaces; one or more beams corresponding to a second edge field of the image are at least partially reflected by a second extreme at least partially reflecting surface from the first set of at least partially reflecting surfaces; and one or more beams corresponding to the center field of the image are at least partially reflected by a third at least partially reflecting surface from the first set of at least partially reflecting surfaces, the third at least partially reflecting surface being disposed between the first extreme at least partially reflecting surface and the second extreme at least partially reflecting surface.

10. The waveguide system according to claim 8, comprising: A primary waveguide having an internal facet configured to receive an image from the projector and perform primary aperture expansion to accommodate the width of the aperture.

11. The waveguide system according to claim 8, wherein the image projector comprises: Projector aperture, which corresponds to the aperture of the first waveguide section; A matrix configured to generate the image to be projected; A collimating lens, configured to receive and collimate light corresponding to an image generated by the matrix; as well as A phase element is disposed relative to the matrix and the collimating lens to control the beam distribution at the projector aperture.

12. The waveguide system according to claim 8, wherein the image projector comprises: Projector aperture, which corresponds to the aperture of the first waveguide section; A matrix configured to generate the image to be projected; as well as A phase element, disposed in the projector, controls the beam distribution at the projector aperture such that one or more beams corresponding to the central field of the image generated by the matrix leave the projector aperture at a location other than the center of the projector aperture.

13. The waveguide system according to claim 8, wherein the image projector comprises: Projector aperture, which corresponds to the aperture of the first waveguide section; A matrix configured to generate the image to be projected; as well as A phase element, disposed in the projector, controls the beam distribution at the projector aperture such that one or more beams corresponding to the edge field of the image generated by the matrix exit the projector aperture at the center of the projector aperture.

14. The waveguide system according to claim 8, wherein the image projector comprises: Projector aperture, which corresponds to the aperture of the first waveguide section; A matrix configured to generate the image to be projected; as well as A phase element, disposed in the projector, for controlling the beam distribution at the projector aperture, wherein the phase element is one or more of the following: A transparent wafer having an embossed pattern on its edge, through which one or more light beams travel; or a diffractive optical element through which one or more light beams travel.

15. The waveguide system of claim 8, the image projector comprising: a projector aperture corresponding to an aperture of the first waveguide portion; a matrix configured to generate an image to be projected; a collimating lens optically disposed between the projector aperture and the matrix and configured to receive and collimate light corresponding to the image generated by the matrix; and a phase element optically disposed between the matrix and the collimating lens to control a beam distribution at the projector aperture.

16. The waveguide system of claim 8, the image projector comprising: a projector aperture corresponding to an aperture of the first waveguide portion; a light source; a matrix optically disposed between the projector aperture and the light source and configured to receive light from the light source and generate an image to be projected; a collimating lens optically disposed between the projector aperture and the matrix and configured to receive and collimate light corresponding to the image generated by the matrix; a phase element optically disposed between the light source and the matrix to control a beam distribution at the projector aperture; and an optical device optically disposed between the light source and the phase element and configured to optimize optical power coupling at the projector aperture while minimizing optical power required by the phase element.

17. The waveguide system of claim 8, the image projector comprising: a projector aperture corresponding to an aperture of the first waveguide portion; a light source; a matrix optically disposed between the projector aperture and the light source and configured to receive light from the light source and generate an image to be projected; a phase element optically disposed between the light source and the matrix to control a beam distribution at the projector aperture; a polarizing beam splitter (PBS) optically disposed between the light source and the projector aperture and configured to reflect light of a first polarization from the light source through the phase element to the matrix, reflect light of a second polarization from the matrix through the phase element to a polarizing reflector, and reflect light of the first polarization from the polarizing reflector to the projector aperture; and an optical device optically disposed between the light source and the phase element and configured to optimize optical power coupling at the projector aperture while minimizing optical power required by the phase element.

18. The waveguide system of claim 8, the image projector comprising: a projector aperture corresponding to an aperture of the first waveguide portion; a light source; a matrix optically disposed between the projector aperture and the light source and configured to receive light from the light source and generate an image to be projected; a collimating lens optically disposed between the projector aperture and the matrix and configured to receive and collimate light corresponding to the image generated by the matrix; a phase element optically disposed between the light source and the matrix to control beam distribution at the projector aperture; and optics optically disposed between the light source and the phase element and between the phase element and the matrix and configured to optimize light power coupling at the projector aperture while minimizing light power required by the phase element.

19. The waveguide system of claim 8, the image projector comprising: a projector aperture corresponding to the aperture of the first waveguide portion; a light source; a matrix optically disposed between the projector aperture and the light source and configured to receive light from the light source and generate an image to be projected; a phase element optically disposed between the light source and the matrix to control beam distribution at the projector aperture; a polarizing beam splitter (PBS) optically disposed between the light source and the projector aperture and configured to reflect light of a first polarization from the light source through the phase element to the matrix, reflect light of a second polarization from the matrix to the polarizing reflector, and reflect light of the first polarization from the polarizing reflector to the projector aperture; and optics optically disposed between the light source and the phase element and between the phase element and the matrix and configured to optimize light power coupling at the projector aperture while minimizing light power required by the phase element.

20. The waveguide system of claim 8, the image projector comprising: a projector aperture corresponding to the aperture of the first waveguide portion; a light source; and a matrix optically disposed between the projector aperture and the light source and configured to receive light from the light source and generate an image to be projected, wherein each reflective pixel element on the matrix is disposed at a respective tilt to control beam distribution at the projector aperture.

21. The waveguide system of claim 8, the image projector comprising: a projector aperture corresponding to the aperture of the first waveguide portion; a light source; and a matrix optically disposed between the projector aperture and the light source and configured to receive light from the light source and generate an image to be projected, ​ ​ ​ ​ wherein each reflective pixel element on the matrix is disposed at a respective tilt such that one or more light beams corresponding to a center field of the image exit the projector aperture at an edge of the projector aperture.

22. The waveguide system of claim 8, the image projector comprising: a projector aperture corresponding to an aperture of the first waveguide portion; a light source; and a matrix optically disposed between the projector aperture and the light source and configured to receive light from the light source and generate an image to be projected, wherein each reflective pixel element on the matrix is disposed at a respective tilt such that one or more light beams corresponding to an edge field of the image exit the projector aperture at a center of the projector aperture.

23. The waveguide system of claim 8, the image projector comprising: a projector aperture corresponding to an aperture of the first waveguide portion; a light source; a matrix optically disposed between the projector aperture and the light source and configured to receive light from the light source and generate an image to be projected; and a polarizing beam splitter (PBS) optically disposed between the light source and the projector aperture and configured to reflect light of a first polarization from the light source to the matrix, reflect light of a second polarization from the matrix to a polarizing reflector, and reflect light of the first polarization from the polarizing reflector to the projector aperture, wherein each reflective pixel element on the matrix is disposed at a respective tilt such that one or more light beams corresponding to an edge field of the image exit the projector aperture at a center of the projector aperture.

24. The waveguide system of claim 8, the image projector comprising: two or more projectors adjacent to one another, a first projector having a first projector aperture corresponding to a first portion of an aperture of the first waveguide portion and a second projector having a second projector aperture corresponding to a second portion of the aperture of the first waveguide portion, the second portion of the aperture of the first waveguide portion being different than the first portion of the aperture of the first waveguide portion, the first projector configured to project a first portion of the image and the second projector configured to project a second portion of the image, the second portion of the image being different than the first portion of the image.

25. An image projector comprising: a projector aperture; a matrix configured to generate an image to be projected; a collimating lens configured to receive and collimate light corresponding to the image generated by the matrix; and a phase element disposed in the projector to control a distribution of light beams at the projector aperture such that one or more light beams corresponding to a center field of the image generated by the matrix exit the projector aperture at an edge of the projector aperture.

26. The image projector of claim 25, wherein, The phase element is disposed in the projector to control a beam distribution at the projector aperture such that one or more beams corresponding to an edge field of an image generated by the matrix exit the projector aperture at a center of the projector aperture.

27. The image projector of claim 25, wherein, The phase element is one or more of: a transparent wafer having a relief pattern on an edge through which one or more beams travel; or a diffractive optical element through which one or more beams travel.

28. The image projector of claim 25, wherein, the collimating lens is optically disposed between the projector aperture and the matrix; and the phase element is optically disposed between the matrix and the collimating lens to control a beam distribution at the projector aperture.

29. The image projector of claim 25, comprising: optics, wherein, the matrix is optically disposed between the projector aperture and the light source; the collimating lens is optically disposed between the projector aperture and the matrix; the phase element is optically disposed between the light source and the matrix to control a beam distribution at the projector aperture; and the optics are optically disposed between the light source and the phase element, and the optics are configured to optimize light power coupling at the projector aperture while minimizing light power required by the phase element.

30. The image projector of claim 25, comprising: a polarizing beam splitter (PBS) configured to reflect light of a first polarity from the light source through the phase element to the matrix, reflect light of a second polarity from the matrix through the phase element to a polarizing reflector, and reflect light of the first polarity from the polarizing reflector to the projector aperture; and optics, wherein, the matrix is optically disposed between the projector aperture and the light source; the phase element is optically disposed between the light source and the matrix to control a beam distribution at the projector aperture; the PBS is optically disposed between the light source and the projector aperture, and the optics are optically disposed between the light source and the phase element, and the optics are configured to optimize light power coupling at the projector aperture while minimizing light power required by the phase element.

31. The image projector of claim 25, comprising: optics, wherein, the matrix is optically disposed between the projector aperture and the light source, the collimating lens is optically disposed between the projector aperture and the matrix, the phase element is optically disposed between the light source and the matrix, and the optics are optically disposed between the light source and the phase element and between the phase element and the matrix, and the optics are configured to optimize light power coupling at the projector aperture while minimizing light power required by the phase element. ​ 32. The image projector of claim 25, comprising: a polarizing beam splitter (PBS) configured to reflect light of a first polarity from the light source through the phase element to the matrix, reflect light of a second polarity from the matrix to a polarizing reflector, and reflect light of the first polarity from the polarizing reflector to the projector aperture; and an optical device, wherein the matrix is optically disposed between the projector aperture and the light source, the phase element is optically disposed between the light source and the matrix, the polarizing beam splitter (PBS) is optically disposed between the light source and the projector aperture, and the optical device is optically disposed between the light source and the phase element and between the phase element and the matrix, and the optical device is configured to optimize light power coupling at the projector aperture while minimizing light power required by the phase element.

33. A waveguide system for a near-eye display, comprising: a first waveguide portion having first and second major surfaces and an aperture through which a light beam corresponding to an image from an image projector enters the waveguide system, the first waveguide portion configured to propagate the light in a first dimension and a second dimension non-parallel to the first dimension while guiding the light in a third dimension non-parallel to the first and second dimensions by total internal reflection between the first and second major surfaces; a redirecting component configured to receive the light beam from the first waveguide portion and redirect the light beam in a third dimension non-parallel to the first and second dimensions; a second waveguide portion having first and second major surfaces and configured to receive the light beam redirected by the redirecting component and guide the light beam in the second dimension by total internal reflection between the first and second major surfaces such that the light propagates in the third and first dimensions; and one or more first optical elements disposed in the first waveguide portion, the second waveguide portion, or between the first and second waveguide portions and configured to expand the aperture in the first dimension; and one or more second optical elements disposed in the second waveguide portion and configured to couple out the image in the second dimension to expand the aperture in the third dimension.

34. The waveguide system of claim 33, wherein, The redirecting component is one or more of a reflective element and a prism.

35. The waveguide system of claim 33, wherein, The redirecting component corresponds to the one or more first optical elements.

36. The waveguide system of claim 33, comprising a waveplate disposed between the first and second waveguide portions.

37. The waveguide system of claim 33, wherein, A thickness between the first and second major surfaces of the first waveguide portion is thicker than a thickness between the first and second major surfaces of the second waveguide portion.

38. The waveguide system of claim 33, wherein, The first and second waveguide portions are disposed perpendicular to each other as viewed from a side view of the waveguide system.

39. The waveguide system of claim 33, wherein, A thickness between the first and second major surfaces of the first waveguide portion is thicker than a thickness between the first and second major surfaces of the second waveguide portion.

40. The waveguide system of claim 33, wherein, The one or more second optical elements correspond to a second set of parallel partially-reflecting surfaces disposed at an oblique angle with respect to the first and second major surfaces of the second waveguide portion.

41. The waveguide system of claim 33, wherein, The one or more first optical elements correspond to a first set of parallel partially-reflecting surfaces or to a first diffractive grating, and the one or more second optical elements correspond to a second set of parallel partially-reflecting surfaces or to a second diffractive grating.

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