Waveguide with embedded leak image pipes

Abstract

The optical device may include: a waveguide having a front and a parallel rear surface; a first aperture expander configured to receive an input image beam and provide a first plurality of expanded image beams, wherein the first plurality of expanded image beams are configured to propagate and reflect between the front and rear surfaces; a leak image pipe configured to receive a first portion of the first plurality of expanded image beams and provide a plurality of transmitted image beams, wherein the first portion of the first plurality of expanded image beams is configured to be partially reflected within the leak image pipe; and a second aperture expander located in the waveguide and configured to receive a second portion of the first plurality of expanded image beams and a plurality of transmitted image beams, wherein the second aperture expander is configured to provide a second plurality of expanded image beams that exit through the rear surface.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit of priority under 35 U.S.C. § 119(e) of U.S. Patent Application No. 63 / 459,727, filed on April 17, 2023, entitled "Embedded Light Guiding Slab", the entire disclosure of which is incorporated herein by reference.

Background Art

[0002] Unless otherwise stated in this specification, the materials described in this section are not prior art to the claims of this application and are not admitted to be prior art by virtue of being included in this section. This disclosure generally relates to optical devices and systems related to wearable devices for use in augmented reality applications, and more specifically, to improved wearable devices for directly providing optical information to a user.

[0003] Wearable optical devices such as near - eye displays or smart glasses for use in augmented reality applications are often cumbersome to wear and use, thus limiting their comfort and practicality. Current wearable optical devices can also have a restricted field of view (FoV) that may be undesirable for the user and, in some situations, may affect safety. However, increasing the field of view typically requires pushing the limits of geometric boundaries, which can be costly and lead to product form factors and / or aesthetic appearances that may not be acceptable in the market. What is needed are solutions to address these and other problems.

Summary of the Invention

[0004] An optical device is generally described according to the embodiments. The optical device may include: a waveguide having a front and rear surface parallel to each other; a first aperture expander disposed within the waveguide and configured to receive an input image beam coupled by internal reflection to provide a first plurality of expanded image beams, the first plurality of expanded image beams configured to propagate and reflect between the front and rear surfaces; a leak image pipe disposed within the waveguide and configured to receive a first portion of the first plurality of expanded image beams to provide a plurality of transmitted image beams, the first portion of the first plurality of expanded image beams configured to be partially reflected within the leak image pipe; and a second aperture expander disposed within the waveguide and configured to receive a second portion of the first plurality of expanded image beams and a plurality of transmitted image beams, the second aperture expander configured to provide a second plurality of expanded image beams configured to exit through the rear surface.

[0005] According to this embodiment, the leakage image pipe is an optical device comprising an input surface, an output surface, and an inner surface, wherein the inner surface has a transparent coating that progresses continuously in the direction from the input surface to the output surface, the inner surface has a transparent coating that progresses discretely in the direction from the input surface to the output surface, and the inner surface has a uniform transparent coating. The first aperture expander may include a first plurality of partial reflective facets, the first plurality of partial reflective facets being inclined at an angle and oblique to at least one of a front surface and a plane perpendicular to the front surface, and perpendicular to the front surface. An optical device wherein an input image beam is injected into a waveguide in a coupling region and propagates through a first aperture expander in a first direction away from the coupling region, and the reflectance of a first plurality of partial reflective facets increases in the direction away from the coupling region, the reflectance of a first plurality of partial reflective facets is constant in the direction away from the coupling region, the first aperture expander has a terminal facet that is a partial reflective facet, and the first aperture expander has a terminal facet that is a mirror. An optical device wherein the leakage image pipe is an elongated member having orthogonal sides and a rectangular cross-section, and the leakage image pipe has an outer surface that is at least one of being aligned perpendicular to the front, aligned not perpendicular to the front, and aligned at an angle with the horizontal axis. An optical device wherein the leakage image pipe may further include an outer surface having a mirror disposed on the side of the leakage image pipe opposite to the second aperture expander.

[0006] According to this embodiment, the leak image pipe may further include an outer surface and an input surface configured to receive first portions of a first plurality of expanded image beams, wherein the input surface is perpendicular to the front surface and inclined with respect to the outer surface at an angle in the range of 20° to 160°. The optical device further comprises a first leakage image pipe, a plurality of reflected image beams being a first plurality of transmitted image beams transmitted through a first inner surface oriented toward a second aperture expander, an input surface being a first input surface, and the optical device may further include a second leakage image pipe disposed in a waveguide on the side of the second aperture expander opposite to the first leakage image pipe, the second leakage image pipe being configured to receive a third portion of the first plurality of expanded image beams and provide a second plurality of transmitted image beams through a second inner surface oriented toward the second aperture expander, and the second aperture expander being configured to receive a first plurality of transmitted image beams, a second plurality of transmitted image beams, and a second portion of the first plurality of expanded image beams and provide a second plurality of expanded image beams configured to exit through a rear surface.

[0007] According to this embodiment, an optical device wherein at least one of a first leak image pipe and a second leak image pipe is arranged at an angle with respect to the horizontal axis of the waveguide. An optical device wherein the second aperture expander comprises a second plurality of partial reflective facets inclined at an angle oblique to at least one of a front plane and a plane perpendicular to the front plane. An optical device wherein a second portion of the first plurality of expanded image beams and a plurality of reflected image beams are directed toward an eye movement box. An optical device wherein the waveguide further comprises a partial plane reflector as a first homogenization layer arranged in the plane between the front and rear surfaces of the leak image pipe. An optical device wherein the leak image pipe further comprises a second homogenization layer arranged in the plane between the front and rear surfaces of the leak image pipe. An optical device wherein the leak image pipe further comprises a third homogenization layer arranged in the plane between the inner and outer surfaces of the leak image pipe. Optical device comprising a leak image pipe further comprising a fourth homogenization layer having a first portion disposed between a first aperture expander and a second aperture expander, the fourth homogenization layer having a second portion disposed between the leak image pipe and the second aperture expander. Optical device further comprising an image projector configured to generate a collimated image beam based on a digital image, the collimated image beam being infinitely collimated; an input coupler configured to receive an input image beam and provide an output image beam injected into a waveguide in a coupling region; and a fifth homogenization layer disposed between the image projector and the input coupler.

[0008] In another embodiment, an optical system is generally described. The optical system includes a waveguide having a front and rear surface parallel to each other, an image projector configured to generate a collimated image beam based on a digital image, wherein the collimated image beam is infinitely collimated, an input coupler configured to receive the collimated image beam and output an input image beam injected into the waveguide in a coupling region, a first aperture expander disposed in the waveguide and configured to receive the input image beam and provide a first plurality of expanded image beams, wherein the first plurality of expanded image beams are configured to propagate and reflect between the front and rear surfaces, and in the waveguide The invention may include: a leakage image pipe disposed and configured to receive first portions of a first plurality of expanded image beams and to provide a plurality of transmitted image beams, wherein the first portions of the first plurality of expanded image beams are configured to be partially reflected within the leakage image pipe, and the leakage image pipe is an elongated member having orthogonal sides and a rectangular cross-section; and a second aperture expander disposed within a waveguide and configured to receive second portions of the first plurality of expanded image beams and a plurality of reflected image beams, wherein the second aperture expander is configured to provide a second plurality of expanded image beams that are configured to exit through its rear surface.

[0009] According to this embodiment, the optical system comprises an input surface, an output surface, and an inner surface, wherein the inner surface has a transparent coating that progresses continuously in the direction from the input surface to the output surface, the inner surface has a transparent coating that progresses discretely in the direction from the input surface to the output surface, and the inner surface has a uniform transparent coating. The optical system comprises a first aperture expander comprising a first plurality of partial reflective facets, the first plurality of partial reflective facets inclined at an angle that is oblique to at least one of a front surface and a plane perpendicular to the front surface, and at an angle that is perpendicular to the front surface, and a second aperture expander comprising a second plurality of partial reflective facets that are oblique to at least one of a front surface and a plane perpendicular to the front surface and inclined at a certain angle. An optical system further comprising: an outer surface having a mirror disposed perpendicular to the front surface, the outer surface and the mirror disposed on the side of the leak image pipe opposite to the second aperture expander; and an input surface configured to receive first portions of a first plurality of expanded image beams, the input surface being perpendicular to the front surface and inclined with respect to the outer surface at an angle in the range of 20° to 160°.

[0010] The above summary is illustrative and not intended to be limiting. Further embodiments, features, and characteristics beyond those described above will become apparent by referring to the drawings and the detailed description below. In the drawings, similar reference numerals indicate the same or functionally similar elements. [Brief explanation of the drawing]

[0011] [Figure 1] Block diagrams of optical systems according to various embodiments of this disclosure are illustrated below. [Figure 2A] Front plan views of optical systems including waveguides, based on various embodiments, are illustrated. [Figure 2B] The side and plan views of the optical system including the waveguide shown in Figure 2A, based on various embodiments, are illustrated below. [Figure 3A] Front plan views of optical systems including waveguides, based on various embodiments, are illustrated. [Figure 3B] The side and plan views of the optical system including the waveguide shown in Figure 3A, based on various embodiments, are illustrated below. [Figure 4] Front plan views of optical systems including waveguides, based on various embodiments, are illustrated. [Figure 5] Front plan views of optical systems including waveguides, based on various embodiments, are illustrated. [Figure 6] Front plan views of optical systems including waveguides, based on various embodiments, are illustrated. [Figure 7] Front plan views of optical systems including waveguides, based on various embodiments, are illustrated. [Figure 8] Front plan views of optical systems including waveguides, based on various embodiments, are illustrated. [Figure 9] Front plan views of optical systems including waveguides, based on various embodiments, are illustrated. [Figure 10] Front plan views of optical systems including waveguides, based on various embodiments, are illustrated. [Figure 11] Front plan views of optical systems including waveguides, based on various embodiments, are illustrated. [Figure 12] Front plan views of optical systems including waveguides, based on various embodiments, are illustrated. [Modes for carrying out the invention]

[0012] In the following description, many specific details such as particular structures, components, materials, dimensions, processing steps, and techniques are described in order to provide an understanding of the various embodiments of this application. However, it will be understood by those skilled in the art that the various embodiments of this application can be practiced without these specific details. In other cases, well-known structures or processing steps are not described in detail in order to avoid obscuring this application.

[0013] For further details, wearable devices such as near-eye displays and / or smart glasses can be implemented by the systems and methods described in accordance with this disclosure. The systems can efficiently provide users with high-quality optical information in a variety of applications.

[0014] Figure 1 illustrates a block diagram of an optical system according to various embodiments of the present disclosure. The optical system 100 may include two or more devices or components. The optical system 100 may generally be implemented as a hybrid system including various electronic, optical, and electro-optical elements. An optical device 102 may include one or more elements from the optical system 100. For further detail below, the optical system 100 may include one or more wearable devices 110, such as near-eye displays or smart glasses, which may be worn on or around the user's head to transmit optical information to one or more of the user's eyes.

[0015] The wearable device 110 may include a controller 114 having a memory 116, which may be configured to operate the wearable device 110, for example, by executing program instructions stored in the memory 116 to transmit and receive electrical signals to and from various other elements within the optical system 100, process and provide information, and interact with other systems outside the wearable device 110. The controller 114 may include a microcontroller, a processor, various individual components, programmable logic devices, and / or various interface circuits that can access the memory 116, which may be removable, replaceable, programmable, and reprogrammable, to update instructions to the controller 114.

[0016] The wearable device 110 may also include a power management module 120 having a battery 122, and the power management module 120 may be configured to charge, discharge, and monitor power usage of the battery 122. For example, various elements of the wearable device 110, including the controller 114, the image projector 126, and the optical engine 134, may receive power from the battery 122. The wearable device 110 may also include one or more image projectors 126, each configured to generate a collimated image beam based on a digital image 128. The collimated image beam may be an illumination representation of a digital image having an image field that is a two-dimensional representation of the digital image, based on either a single graphical image (e.g., a still image) or a sequence of graphical images (e.g., a video). The collimated image beam may be infinitely collimated.

[0017] The wearable device 110 may also include one or more waveguides 130 (e.g., WGs also shown as light guiding optical elements LOEs) comprising a transparent material configured to receive and propagate light, and the light may enter and exit various outer and inner surfaces of the waveguide 130. For example, the transparent material forming the waveguide 130 may include an optical glass or other suitable material that is converted into a composite optical structure using a process that may include coating, laminating, slicing, polishing, and shaping the transparent material. The process may include adding a partially reflective material or a total reflective material, such as a mirror coating. Similarly, the process may also include adding a partially opaque material or a completely opaque material, such as a light cover for blocking light.

[0018] The wearable device 110 may also include one or more optical engines 134 coupled to one or more image projectors 126 and waveguides 130. The optical engine 134 may be configured to directly operate the image projector 126 under the instruction of the controller 114. For example, the optical engine 134 may provide graphic processing of the digital image 128 before projection of the illumination representation of the digital image by the image projector 126.

[0019] The wearable device 110 may also include a frame 138 (e.g., structure) for supporting and holding one or more elements within the wearable device 110. For example, the frame 138 may support and hold the first image projector 126 in a predetermined position adjacent to the first waveguide 130. Similarly, the frame 138 may support and hold the second image projector 126 in a predetermined position adjacent to the second waveguide 130. In this way, the frame 138 may support and hold a pair of one or two image projectors 126 and waveguides 130, for example, on or around the user's head. In this specification, references are made regarding the orientation of various elements relative to each other, and such references may also include references to various elements of the wearable device 110 when supported by the frame 138, or related to three-dimensional (3D) coordinates (e.g., X, Y, Z axes), as described in the associated drawings.

[0020] The optical system 100 may also include a host computer 170 which may include a processor 174 configured to read and execute operations based on instructions 178 stored in a computer-readable medium 180. The instructions 178 may include at least several instructions provided to a controller 114 and stored in memory 116. The host computer 170 can communicate with one or more elements of the wearable device 110 via a signal and power bus 188. In this way, the host computer 170 can control various other elements of the wearable device 110, provide power to charge the battery 122 to provide digital image data to the optical engine 134, provide instructions to the controller 114 and receive status from there.

[0021] Figure 2A illustrates front plan views of optical systems including waveguides according to various embodiments. Figure 2B illustrates side plan views of optical systems including waveguides in Figure 2A according to various embodiments. Referring further to Figures 1 and 2A-2B, these together illustrate an optical system 100 (having optical device 102) in a first configuration, which may include a waveguide 130 (WG130) having a front 202 and a rear 204 parallel to each other. An image projector 126 may be configured to generate a collimated image beam 290 based on a digital image 128, and the collimated image beam may be collimated indefinitely. The collimated image beam may be an illumination representation of a digital image having an image field which is a two-dimensional representation of a digital image, based on either a single graphical image (e.g., a still image) or a sequence of graphical images (e.g., a moving image). The input coupler 292 may be configured to receive the collimated image beam 290 and output the input image beam 212 which is injected into the waveguide 130 in the coupling region 248. Figure 2A illustrates a gap between the image projector 126 and the input coupler 292, but such a gap is for illustrative purposes only, and in this and other embodiments, there may be no gap in the actual embodiment.

[0022] A first aperture expander 208 may be disposed within the waveguide 130 and configured to receive an input image beam 212 coupled by internal reflection to provide a first plurality of expanded image beams 216 expanded to a first dimension. The first plurality of expanded image beams 216 may be configured to propagate and reflect between a front surface 202 and a rear surface 204 (e.g., an outer surface). The first aperture expander 208 may include a first plurality of planar, mutually parallel partial reflective optical elements 242 (e.g., facets, or inner surfaces) that are inclined at an angle that is oblique to at least one of the front surface 202 and a plane 206 perpendicular to the front surface (e.g., the XZ plane), and an angle that is perpendicular to the front surface (e.g., plane 206). Various coupling configurations for the input image beam 212, including mirrors, optical couplers, and other mechanisms, may be used, as will be described more fully below. More generally, the input image beam 212 can be coupled to the waveguide 130 (e.g., the substrate) and the first aperture expander 208 by internal reflection.

[0023] As described, partial reflection can mean partial transmission such that some portion of the illumination incident on a particular facet may be reflected while the rest may be transmitted through the facet, starting from the initial facet 244 at the beginning of the first aperture expander 208 and continuing through the second-to-last facet 256 and the final (e.g., terminal) facet 258, resulting in a first set of planar, mutually parallel partial reflection facets 242, where the illumination moves along the first aperture expander 208 in direction 252 from the initial facet 244 to the terminal facet 258. Thus, the input image beam 290 may be injected into the waveguide 130 in the coupling region 248 and propagate through the first aperture expander 208 in a first direction 252 away from the coupling region 248.

[0024] In one embodiment, the reflectivity of the first plurality of partial reflective facets 242 increases in the direction away from the coupling region 248 to compensate for the reduced illumination transmitted by the conventional facets, and can eventually reach a terminal facet 258 which may be a mirror that reflects only illumination and does not transmit illumination through the mirror. Alternatively, the reflectivity of the first plurality of partial reflective facets 242 may be constant in the direction away from the coupling region 248 until it reaches a terminal facet 258 which may be a mirror. When the reflectivity of the facets is constant, each facet may, for example, be coated with the same coating. In yet another alternative, the terminal facet 258 may have the same (e.g., uniform) partial reflectivity as the other partial reflective facets 242 in various applications, or the terminal facet 258 may have a wedge configuration. In this case, the terminal facet 258 does not have to be a perfect reflective mirror, but may instead be a partial reflective element such as a partial reflective facet or wedge.

[0025] The leak image pipe 220 may be located within the waveguide 130 and may be configured to receive first portions 224 of a first plurality of expanded image beams and provide a plurality of transmitted image beams 228. In this sense, the leak image pipe 220 may be considered embedded within the waveguide 130. The leak image pipe 220 may have the same or different refractive index compared to other components in the waveguide 130. The first portions 224 of the plurality of expanded image beams 216 may be configured to be partially reflected and propagated within the leak image pipe 220. In this way, the light beam may be transmitted through the inner surface 262 of the leak image pipe 220 along the path of light propagation to expand the first portions 224 by partial reflection within the leak image pipe 220 and partial transmission of the transmitted image beams 228 through the inner surface 262, thereby eliminating the need for more partially reflective facets 242 in what would become a longer (e.g., higher) first aperture expander 208. In this way, the leak image pipe 220 can transmit, reflect, and reroute (e.g., tunnel) light rays that would have come from further away. Extending the first section 224 with the leak image pipe 220 may result in a smaller waveguide with the same or better performance when compared, for example, to a larger waveguide with more partial reflection facets. The leak image pipe 220 may be an elongated member having orthogonal sides and a rectangular cross-section, and thus having opposing parallel surfaces configured to preserve the propagation angle of the light rays. In this way, the leak image pipe 220 may have opposing sides that are parallel to each other, generally having a rectangular cross-section, or in one particular embodiment, a square cross-section.

[0026] Furthermore, the reflective walls of the leak image pipe 220 may be perpendicular to the main surface of the waveguide 130. In this way, any ray coupled to the leak image pipe 220 may be coupled from there at exactly the same propagation angle. The leak image pipe 220 may be coated with various optical coatings, such as various reflective coatings, dielectric reflective coatings, and high-reflectivity coatings. The leak image pipe 220 may include an outer surface 260 which can be aligned or positioned parallel to a plane 206 perpendicular to the front surface 202 (e.g., the XZ plane) corresponding to two of three main axes which can be used to describe the orientation of the optical device 102 and / or the waveguide 130. As will be described more fully below, the outer surface 260 of the leak image pipe 220 may also be aligned or positioned at an angle with respect to the horizontal axis 210. Thus, the leak image pipe 220 may be oriented perpendicular to the front surface 202, not perpendicular to the front surface 202, and at an angle with respect to the horizontal axis 210, as illustrated.

[0027] The outer surface 260 of the leak image pipe 220 may further include a mirror 274 (e.g., a mirror coating) that reflects only the illumination inside the leak image pipe 220 and does not transmit light through the outer surface 260. In this way, the illumination reflected inside the leak image pipe 220 can be transmitted through the inner surface 262 of the leak image pipe 220. More specifically, a first portion 224 of a first plurality of extended image beams 216 may enter the input surface 264 (e.g., input aperture 264) of the leak image pipe 220 and propagate as a plurality of reflected beams 230, some portion of the reflected beams 230 can be transmitted through the inner surface 262. The input aperture 264 may be described as the input surface 264 for convenience, but the input aperture 264 can be implemented in various ways. For example, the leak image pipe 220 may be formed from an initial transparent slab having the same or different refractive index as the rest of the waveguide 130 components. In this embodiment, the leak image pipe 220 having a different refractive index may have an actual inlet opening which may have a polished optical surface. Alternatively, when the leak image pipe 220 has the same refractive index as the other components of the waveguide 130, the input opening 264 may be implemented as a parallel but laterally separated coating layer. The input surface 264 may be perpendicular to the front surface 202 and may be inclined with respect to the outer surface 260 at an angle which may range from 20° to 160°, preferably from 35° to 150°, and typically about 90°, as illustrated. In this way, the input surface 264 may form an angle with the illumination coming from the first aperture expander 208, and the angle may range from acute (e.g., angled away from the first aperture expander 208 to take in less illumination) or obtuse (e.g., angled towards the first aperture expander 208 to take in more illumination). In this way, the angle of the input surface 264 (e.g., the entrance pupil) can be used to set or control the amount of illumination captured by the leak image pipe 220, thereby balancing the illumination levels in the waveguide 130 and thus setting an effective aperture as seen from the object side, for example. For integrity, some portion of the reflected beam 230 may exit through the output surface 266 of the leak image pipe 220, which may be negligible.Again, depending on the embodiment, the output surface 266 may not be an optically polished surface. Instead, the output surface 266 may correspond to a parallel but laterally separated end region of the coating, as described. Lateral separation may be important in some embodiments where some portion of the coating can be omitted when light transmitted and reflected by the leak image pipe 220 does not reach the eye movement box 276 and the user's eye. The mirror coating 274 on the outer surface 260 of the leak image pipe 220 may be omitted, for example, in areas of the leak image pipe 220 that are not needed to reflect the image beam to the eye movement box 276. This may be beneficial both, for example, by saving the cost of applying the portion of the mirror coating and by not unnecessarily obscuring the user's view through the non-mirror portion of the waveguide 130.

[0028] A second aperture expander 232 may be disposed within the waveguide 130 and configured to receive second portions 236 of the first plurality of expanded image beams 216 and plurality of transmitted image beams 228. Similar in some respects to the first aperture expander 208, the second aperture expander 232 may include a second plurality of partial reflective facets 272 that are inclined at an angle that may be oblique to at least one of the front surface 202 and a plane 206 perpendicular to the front surface (e.g., the XZ plane). As illustrated, the second portions of the first plurality of expanded image beams 216 and the plurality of transmitted image beams 228 may both be directed to the second aperture expander 232, and the second plurality of expanded image beams 240 may be directed, for example, toward the user's eye adjacent to the eye movement box 276. Thus, the second aperture expander 232 may be configured to provide the second plurality of expanded image beams 240 configured to exit (e.g., transmit) through the rear surface 204. In this way, the first aperture expander 208 and the second aperture expander 232 can cooperate to expand a version of the collimated image beam 290 in two dimensions (2D), thus resulting in a two-dimensional expansion of the input image beam 290 into the coupled output region of the waveguide 130, also described as the eye movement box 276, which is configured to exit through the rear surface 204 toward the user's eye 280.

[0029] Various optical homogenizers (e.g., partial reflection homogenization layers) can also be used alone or in combination to provide, among other advantages, improved image uniformity in intensity. For example, as shown in Figure 2B, waveguide 130 may comprise a partial planar reflector as a first homogenization layer 284, and the partial planar reflector as the first homogenization layer 284 may be positioned in the plane between the front 202 and the rear 204. Waveguide 130 may also comprise a second homogenization layer 286 positioned in the plane between the front 268 and the rear 270 of the leak image pipe 220. In this way, the second homogenization layer 286 may be oriented vertically to homogenize light based on horizontal reflection. Leak image pipe 220 may also include a third homogenization layer 288 positioned in the plane between the inner 262 and the outer 260 of the leak image pipe 220. In this way, the third homogenization layer may be oriented horizontally to homogenize light based on vertical reflection. The third homogenization layer 288 may be a semi-reflective surface added within the leak image pipe 220, such as a film disposed parallel to its reflective wall to fill one or more empty slab openings. As illustrated, a first portion 224 of the first plurality of extended image beams 216 enters the leak image pipe 220 at the inlet opening 264, is partially reflected by the third homogenization layer 288, partially transmitted, and then partially reflected by the inside of the inner surface 262 of the leak image pipe 220. When present, the second homogenization layer 286 may double the beam by reflecting and propagating horizontally within the leak image pipe 220. When present, the third homogenization layer 288 may double the beam by reflecting and propagating vertically within the leak image pipe 220. This description also applies to other homogenizers disclosed herein.

[0030] The eye movement box 276 may be suitably illuminated by illumination propagation 230 in the leak image pipe 220, increasing the field of view (FoV) for the user, eliminating the need for larger optical devices, reducing size, weight, and cost. As described, Figures 2A–2B illustrate an optical system 100 (having optical device 102) in a first configuration, where, as illustrated, the second aperture expander 232 may be inclined toward the first aperture expander 208, the leak image pipe 220 may be positioned vertically below the second aperture expander 232, or the second aperture expander 232 may be positioned above the leak image pipe 220 (e.g., a light guide slab). This is not to be considered limiting. In this embodiment and other embodiments, the waveguide 130 may be rotated in a plane or inverted about a central axis or diagonal axis without departing from the present disclosure.

[0031] Figure 3A illustrates front plan views of optical systems including waveguides according to various embodiments. Figure 3B illustrates side plan views of optical systems including waveguides in Figure 3A according to various embodiments. Referring further to Figures 1 and 2A-2B, these together illustrate an optical system 100 (having optical device 102) in a second configuration in which a second aperture expander 232 may be inclined toward a first aperture expander 208, and a leak image pipe 220 may be positioned vertically above the second aperture expander 232. Thus, in the examples of Figures 3A-3B, this second configuration can be considered to be vertically "inverted" with reference to the examples of Figures 2A-2B described above. This is not considered limiting, and references to the outer surface 260 and the inner surface 262, etc., can be easily understood as relative terms, which can also be identified as the first surface 260 and the second surface 262 located opposite the first surface 260, without departing from the present disclosure, and vice versa. Similar to the size, weight, and cost reductions illustrated by the embodiments of Figures 2A-2B, the embodiments of Figures 3A-3B also illustrate relative size reductions that may be possible, for example, compared to Figure 2A, with a larger waveguide 330 having a larger profile and increased height 332.

[0032] Figure 4 illustrates front plan views of optical systems including waveguides according to various embodiments. Building upon the preceding description in Figures 2A-2B, the embodiments illustrated in Figure 4 include an input surface 264 that is perpendicular to the front surface 202 and can be inclined with respect to the outer surface 260 at an angle that may range from 20° to 160°. In this embodiment, the input surface 264 may form an acute angle (e.g., angled away from the first aperture expander 208 to take in less illumination and reflect more illumination), as illustrated. The input surface 264 may be angled the same as the output surface 266 (e.g., in the same direction and at the same angle), but this is not considered limiting. Similar in some respects to the embodiments in Figures 2A and 3A, a first portion 224 of a first plurality of expanded image beams 216 may enter the input surface 264 of the leak image pipe 220 and propagate as a plurality of reflected beams 230, some portion of the reflected beams 230 may be transmitted through the inner surface 262. Figure 4 illustrates several representative phantom-reflected image beams corresponding to the transmitted image beam 228 from the leak image pipe 220, as if the corresponding transmitted image beam were reflected by the partial reflection facets in a representation of the expanded first aperture expander 208 having an increased number of partial reflection facets. In this way, the use of the leak image pipe 220 may allow the size and / or profile reduction of the waveguide 130 to be implemented as a smaller waveguide 430 having a reduced height 432.

[0033] Figure 5 illustrates front plan views of optical systems including waveguides according to various embodiments. Referring to Figures 1 and 2A-2B together with Figure 5, the optical device 102 may include a leak image pipe 220 having an outer surface 260 which may not be oriented perpendicular to the front surface 202. Alternatively, the outer surface 260 may be rotated about a horizontal axis 210 so that it is angled to reflect illumination toward the rear surface 204 and the second aperture expander 232. Alternatively, the outer surface 260 may be rotated about a horizontal axis 210 so that it is angled to reflect illumination toward the front surface 202, and illumination directed toward the front surface 202 may be reflected toward the second aperture expander 232, for example. In this way, the leak image pipe 220 can receive the first portion 224 and at least one additional beam 524 of the first multiple expansion image beams 216 at the inlet opening 264, so that both the first portion 224 and at least one additional beam 524 of the first multiple expansion image beams 216 can be reflected and propagated within the leak image pipe 220. In this way, the first portion 224 can provide a transmitted beam 228 that can be transmitted through the inner surface 262 toward the eye movement box 276 and a reflected beam 230 within the leak image pipe 220. Similarly, at least one additional beam 524 can provide a transmitted beam 528 that can be transmitted through the inner surface 262 toward the eye movement box 276, as described above, and at least one reflected beam 530 that can be reflected within the leak image pipe 220. Only representative beams are illustrated in Figure 5 and other figures, but it should be understood that many other image beams can be received, transmitted, reflected, and propagated in practical implementations.

[0034] Figure 6 illustrates front plan views of optical systems including waveguides according to various embodiments. Similar in some respects to the embodiments illustrated in Figures 2A-2B, Figure 6 illustrates a waveguide 130 having a separation distance 602 between a first aperture expander 208 and a second aperture expander 232, where the separation distance 602 provides, for example, a gap between the first aperture expander 208 and the second aperture expander 232, which can be used to position the eye movement box 276 far from the first aperture expander.

[0035] Figure 7 illustrates front plan views of optical systems including waveguides according to various embodiments. Similar in some respects to the embodiments illustrated in Figures 2A-2B and 6 above, Figure 7 illustrates a waveguide 130 having a separation distance 702 between a first aperture expander 208 and a second aperture expander 232, where the separation distance 702 may be less than 602 due to the addition of a fifth homogenization layer 794 (e.g., a fifth mixer 794) disposed between the image projector 126 and the input coupler 292. This configuration may enable a smaller form factor by pre-homogenizing the image beam, thereby enabling a reduction in the separation distance between the first aperture expander 208 and the second aperture expander 232, and as a result, the leak image pipe 220 may be juxtaposed adjacent to the facets of the first aperture expander 208. In comparison, the configuration illustrated in Figure 7 may provide a more compact (e.g., smaller) waveguide 130 based on a relatively small separation distance 702 to reduce the gap between the first aperture expander 208 and the second aperture expander 232, which may be used to place the eye movement box 276 closer to the first aperture expander 208, leading to, for example, a smaller profile for waveguide 130.

[0036] Figure 8 illustrates front plan views of optical systems including waveguides according to various embodiments. Similar in some respects to the embodiments illustrated in Figures 2A-2B, Figure 8 illustrates an embodiment of a leak image pipe 220 including an input surface 264, an output surface 266, and an inner surface 262 (e.g., a transmissive surface from which a reflected image beam can exit) which may have a coating 802 that is uniformly transmissive with the same transmittance across the surface, or an inner surface 262 that has a progressively transmissive coating applied in the direction from the input surface 264 to the output surface 266. In this sense, the inner surface 262 may have a uniformly transmissive coating. As illustrated, a progressively transmissive coating may allow an increasing amount of illumination to be transmitted through the inner surface 262 based on an increasing linear distance from the input surface 264. In other words, the coating 802 may be progressively reflective to allow a larger proportion of light energy to be transmitted through the inner surface 262 based on the distance from the input surface 264. The increasing transmittance of the coating 802 (corresponding to the decreasing reflectance) may follow a continuous, progressive slope or gradient of higher reflectance at the input surface 264 toward lower reflectance at the output surface 266. In this sense, the inner surface 262 may have a transmittance coating that progresses continuously in the direction from the input surface 264 to the output surface 266. Alternatively, the transmittance coating 802 may include a discrete, stepwise, or stepped increase in transmittance (e.g., a corresponding discrete or stepwise decrease in reflectance) based on adjacent discrete coating regions, including a first coating region 804 having a mirror coating (e.g., fully reflective) on a first region of the inner surface 262 oriented toward the internal region of the leak image pipe 220, and a mirror 274 on the outer surface 260 for forming an input opening 264 so that illumination does not pass through the first coating region 804. Next, the progressively transparent coating 802 may include a second coating region 806 at a second linear distance that is more transparent than the mirror coating on the portion of the inner surface corresponding to the first coating region 804. Similarly, the progressively transparent coating 802 may include a third coating region 808 at a third linear distance that is even less reflective and more transparent.This pattern may continue to a fourth coating region 810, which has higher transmittance than the third coating region 808 but lower transmittance than the fifth coating region 812. Finally, the sixth coating region 814 may be the most transmittance region of the progressively transmittance coating 802, allowing any remaining illumination to be transmitted through the inner surface 262 if it has not yet been exhausted. In this sense, the inner surface 262 may have a discretely progressively transmittance coating in the direction from the input surface 264 to the output surface 266. In this way, the amount of illumination provided by the reflected image light in the leak image pipe 220 can be controlled and balanced before coupling to the coupled output region of the eye movement box 276. The progressively transmittance coating 802 may be applied as the same reflective and / or transmittance material applied multiple times for higher reflectance and lower transmittance, or different coating materials may be used for each region. The second-to-last facet 256 and the final (e.g., terminal) facet 258 at the end of the first aperture expander 208 may similarly include greater reflectivity and lower transmittance for facet 256 compared to facet 258, in order to ensure that the maximum amount of illumination is redirected to the leak image pipe 220. In this embodiment, the coating forming the outer surface 260 may be shortened (e.g., omitted in the initial portion) to allow filling of the input aperture 264. Although these terms may be used together, the input aperture 264 may also be defined as the vertical region between the inner surface 262 and the outer surface 260 adjacent to the portion of the leak image pipe 220 on the left side (as illustrated) where the mirror coating 274 of the outer surface 260 begins.

[0037] As described, image illumination can be injected into the leak image pipe 220 to fill the first surface 264. In one embodiment, using only a single reflective coating may produce non-uniform illumination within the eye movement box 276. To address this, multiple or varying coatings may be used across the coupled output region of the eye movement box 276 when reflectivity is reduced (e.g., fewer layers of impedance or reflective coating, so transmittance is increased), leading to more uniform illumination across the eye movement box 276. Corresponding high-reflectivity coatings may be added to the first aperture expansion facets 256 and 258 to ensure that sufficient light power is injected into the leak image pipe 220 to achieve more uniform illumination.

[0038] Figure 9 illustrates front plan views of optical systems including waveguides according to various embodiments. Similar in some respects to the embodiments illustrated in Figures 2A-2B, Figure 9 illustrates an embodiment of a horizontal axis 210 and a leak image pipe 220 aligned at a certain angle 902. The angle 902 may provide optical designers with more freedom by offering greater flexibility in the design of various coatings and may also improve area utilization, such as freeing up a portion of the waveguide 130 that may have previously been covered by a portion of the leak image pipe 220 in the horizontal direction. The angle 902 may vary between 0° and 30°, preferably between 15° and 20°.

[0039] Figure 10 illustrates front plan views of optical systems including waveguides according to various embodiments. Similar in some respects to the embodiments illustrated in Figures 2A-2B, Figure 10 illustrates an embodiment of a leak image pipe 220 that is significantly short and laterally displaced, positioned relatively close to the first aperture expander 208 and relatively far from the second aperture expander 232. As described above, illumination emanating from the leak image pipe 220 (e.g., illumination transmitted through the inner surface 262) can illuminate the corner area of ​​the eye movement box 276 to provide illumination by the spaced or expanded transmitted image beam 228, as shown above. Figure 10 also illustrates a contour 1002 that may show the outline of a waveguide (WG) for use in a fashion eyeglass frame. In this way, the leak image pipe 220 can be at least partially concealed, for example, within a portion of the frame 138 supporting the waveguide 130.

[0040] Figure 11 illustrates front plan views of optical systems including waveguides according to various embodiments. Similar in some respects to the embodiment in Figure 10, the embodiment in Figure 11 includes the addition of a homogenization layer 1102 having a first portion 1104 disposed between a first aperture expander 208 and a second aperture expander 232, and a second portion 1106 disposed between a leak image pipe 220 and the second aperture expander 232. The homogenization layer 1102 may be considered an L-shaped homogenization region, which may be a combination of the first homogenization region 1104 connected to a second homogenization region 1106, either as a single continuous partial reflection layer (e.g., parallel to the front 202) or as an assembly of two or more regions, to provide additional homogenization of the first multiple expanded image beams 216 and a mixture of direct illumination (e.g., radiation) from the first aperture expander 208 in the homogenization layer section 1104 and illumination propagated from the leak image pipe 220 in the homogenization layer section 1106.

[0041] Figure 12 illustrates front plan views of optical systems including waveguides according to various embodiments. Similar in some respects to the descriptions of the various embodiments described above, Figure 12 illustrates an exemplary waveguide 130 having a first leak image pipe 220 disposed on a first side surface (e.g., bottom surface) of a second aperture expander 232 and a second leak image pipe 1220 disposed on a second side surface (e.g., top surface) of the second aperture expander 232 when oriented vertically as illustrated. As described, a first portion 224 of a first plurality of expanded image beams 216 from the first aperture expander 208 may enter a first inlet aperture 264, which is partially transmitted as a plurality of first transmitted image beams 228 through the first inner surface 262 of the first leak image pipe 220 disposed adjacent to the bottom surface of the second aperture expander 232. The inner surface 262 may have a coating 802 which is one of the following: a transparent coating that progresses continuously in the direction from the input surface 264 to the output surface 266, a transparent coating that progresses discretely in the direction from the input surface 264 to the output surface 266, and a uniform transparent coating. In this way, the first portion 224 of the first plurality of expanded image beams 216 may exit the first leak image pipe as expanded beams toward the second aperture expander 232. The first portion 224 of the first plurality of expanded image beams 216 may be partially reflected into the first leak image pipe 220 as a plurality of first reflected image beams 230 that are reflected into the first leak image pipe 220 from the inside of the first outer surface 260 disposed on the side surface of the first leak image pipe 220, away from the second aperture expander 232. Similarly, third portions 1224 of the first plurality of expanded image beams 216 from the first aperture expander 208 may enter a second inlet opening 1264, which is partially transmitted as a plurality of second transmitted image beams 1228 through the second inner surface 1262 of the second leak image pipe 1220, which is disposed adjacent to the upper side of the second aperture expander 232, as illustrated.As described above, the inner surface 1262 may have a coating 1296 which is one of the following: a transparent coating that progresses continuously in the direction from the input surface 1264 to the output surface 1266, a transparent coating that progresses discretely in the direction from the input surface 1264 to the output surface 1266, and a uniform transparent coating. In this way, the third portion 1224 of the first plurality of expanded image beams 216 may exit the second leak image pipe as an expanded beam toward the second aperture expander 232. The third portion 1224 of the first plurality of expanded image beams 216 may also be partially reflected into the second leak image pipe 1220 as a plurality of reflected image beams 1230 that are reflected into the second leak image pipe 1220 from the inside of the second outer surface 1260 disposed on the side surface of the second leak image pipe 1220, away from the second aperture expander 232. The remaining portion of the expanded image beam 216 can be combined with a plurality of first transmitted image beams 228 and a plurality of second transmitted image beams 1228, as described, for example, with reference to Figures 2A and 3A, and applied to a second aperture expander 232, which can be directed toward the user's eye toward the eye movement box 276. In this way, the second aperture expander 232 can receive the first plurality of transmitted image beams 228, the second plurality of transmitted image beams 1228, and the second portion 236 of the first plurality of expanded image beams 216, and provide a second plurality of expanded image beams 240 configured to exit through the rear surface 204. In this embodiment, a first leak image pipe 220 and a second leak image pipe 1220 can receive and process opposite beam directions to avoid generating ghost images.

[0042] The various features described separately above can be combined unless they are incompatible with each other. For example, either or both of the first leak image pipe 220 and the second leak image pipe 1220 illustrated in Figure 12 can be replaced by a leak image pipe 220 aligned at an angle 902 with respect to the horizontal axis 210, as in the embodiment described with reference to Figure 9. Furthermore, either or both of the first leak image pipe 220 and the second leak image pipe may include one or more homogenizers, such as homogenization layers 286 and 288, described with reference to Figures 2A and 2B.

[0043] The terms used herein are intended solely to describe specific embodiments and are not intended to limit the invention. Where used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context otherwise explicitly indicates. It will be further understood that, when used herein, the terms “includes,” “comprises,” and / or “comprising” specify the presence of a described feature, integral, step, action, element, and / or component, but do not exclude the presence or addition of one or more other features, integrals, steps, actions, elements, components, and / or groups thereof. Furthermore, terms such as top, bottom, vertical, horizontal, front, rear, inside, and outside may describe, and should not be considered limiting, the relative arrangement of elements in specific drawings illustrated in the drawings. Such technical terms may be applied in reverse, for example, when the figure or element is reversed.

[0044] If any, all means or steps in the following claims, plus corresponding structures, materials, actions, and equivalents of functional elements, are intended to encompass any structures, materials, or actions to achieve a function in combination with other claimed elements when specifically claimed. The description of the present invention is presented for illustrative and explanatory purposes, but is not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Various embodiments have been selected and described to best illustrate the principles and practical applications of the invention, and to enable those skilled in the art to understand the invention in terms of various embodiments with various modifications to suit specific anticipated uses.

Claims

1. An optical device, A waveguide having a front and rear surface that are parallel to each other, A coupling region disposed within the waveguide, configured to receive an input image beam, and further configured to output the input image beam within the waveguide, A first aperture expander disposed within the waveguide and comprising a first plurality of partial reflective facets, wherein the first plurality of partial reflective facets are planar, disposed between the front and rear surfaces, parallel to each other, and non-parallel to the front and rear surfaces, and the first aperture expander is configured to receive the input image beam from the coupling region and to provide a first plurality of expanded image beams that propagate and reflect between the front and rear surfaces. The first portion of the first plurality of partial reflection facets, which are separated from the coupling region, is configured to generate the first portion of the first plurality of extended image beams, A first aperture expander is configured such that a second portion of the first plurality of partial reflection facets adjacent to the coupling region generates a second portion of the first plurality of expanded image beams, A leakage image pipe formed within the waveguide, configured to receive the first portion of the first plurality of expanded image beams, reflect the first portion of the first plurality of expanded image beams within the leakage image pipe via one or more reflective surfaces of the leakage image pipe, and further provide the plurality of transmitted image beams to a second aperture expander via at least one partial reflective surface of the leakage image pipe, An optical device comprising: a second aperture expander disposed within the waveguide and configured to receive the second portion of the first plurality of expanded image beams and the plurality of transmitted image beams, and further to provide a second plurality of expanded image beams that exit the waveguide through the rear surface.

2. The leak image pipe includes an output surface and an inner surface. The inner surface has a permeable coating that progresses continuously and progressively in the direction from the input surface to the output surface. The inner surface has a permeable coating that progresses discretely in the direction from the input surface to the output surface, or The optical device according to claim 1, wherein the inner surface has a uniform permeable coating.

3. The input image beam propagates away from the coupling region in a first direction through the first aperture expander, and The reflectance of the first plurality of partial reflective facets increases in the first direction. The reflectance of the first plurality of partial reflective facets is constant in the first direction. The first aperture expander has a terminal facet that is a partial reflective facet, or The optical device according to claim 1, wherein the first aperture expander has a terminal facet that is a mirror.

4. The leak image pipe is an elongated member having orthogonal sides and a rectangular cross-section. The leak image pipe has an outer surface, and the outer surface is Aligned perpendicularly to the aforementioned front surface, Aligned non-perpendicular to the aforementioned front surface, or The optical device according to claim 1, wherein the horizontal axis of the waveguide is aligned at a certain angle.

5. The aforementioned leak image pipe is The optical device according to claim 4, further comprising an outer surface having a mirror disposed on the side of the leak image pipe opposite to the second aperture expander.

6. The aforementioned leak image pipe is The optical device according to claim 1, further comprising an outer surface, wherein the input surface is perpendicular to the front surface and inclined at 20° to 160° with respect to the outer surface.

7. The aforementioned leak image pipe is a first leak image pipe, The plurality of transmitted image beams are the first plurality of transmitted image beams, The aforementioned input surface is the first input surface, The aforementioned at least one partial reflective surface is a first at least one partial reflective surface, The third portion of the first plurality of partial reflection facets is configured to generate the third portion of the first plurality of extended image beams and to provide the third portion of the first plurality of extended image beams to the second leak image pipe. The optical device further comprises a second leakage image pipe disposed in the waveguide on the side of the second aperture expander opposite to the first leakage image pipe, the second leakage image pipe configured to receive the third portion of the first plurality of expanded image beams and to provide the second plurality of transmitted image beams to the second aperture expander via a second partial reflecting surface of the second leakage image pipe, The optical device according to claim 1, wherein the second aperture expander is further configured to receive the second plurality of transmitted image beams.

8. The optical device according to claim 7, wherein the first leak image pipe or the second leak image pipe is arranged at an angle with respect to the horizontal axis of the waveguide.

9. The optical device according to claim 1, wherein the second aperture expander comprises a second plurality of partial reflective facets, the second plurality of partial reflective facets being planar, disposed between the front surface and the rear surface, parallel to each other, and oblique to the front surface or a plane perpendicular to the front surface.

10. The optical device according to claim 1, wherein the second plurality of extended image beams are directed to an eye movement box.

11. The optical device according to claim 1, wherein the waveguide further comprises a homogenization layer disposed in the plane between the front surface and the rear surface.

12. The optical device according to claim 1, wherein the leak image pipe further comprises a homogenization layer disposed on the plane between the front and rear surfaces of the leak image pipe.

13. The optical device according to claim 1, wherein the leak image pipe further comprises a homogenization layer disposed on a plane between the inner and outer surfaces of the leak image pipe.

14. The optical device according to claim 1, wherein the leakage image pipe further comprises a homogenization layer having a first portion disposed between the first aperture expander and the second aperture expander, and a second portion disposed between the leakage image pipe and the second aperture expander.

15. An image projector configured to generate an input image beam that is infinitely collimated based on a digital image, An input coupler configured to receive the input image beam and provide the input image beam to the coupling region, The optical device according to claim 1, further comprising a homogenizing layer disposed between the image projector and the input coupler.

16. An optical system, A waveguide having a front and rear surface that are parallel to each other, An image projector configured to generate an infinitely collimated collimated image beam based on a digital image, An input coupler configured to receive the collimated image beam and output the input image beam into the waveguide in the coupling region, A first aperture expander disposed within the waveguide and comprising a first plurality of partial reflective facets, wherein the first plurality of partial reflective facets are planar, disposed between the front and rear surfaces, parallel to each other, and non-parallel to the front and rear surfaces, and the first aperture expander is configured to receive the input image beam from the coupling region and to provide a first plurality of expanded image beams that propagate and reflect between the front and rear surfaces. The first portion of the first plurality of partial reflection facets, which are separated from the coupling region, is configured to generate the first portion of the first plurality of extended image beams, A first aperture expander is configured such that a second portion of the first plurality of partial reflection facets adjacent to the coupling region generates a second portion of the first plurality of expanded image beams, A leakage image pipe formed within the waveguide, configured to receive the first portion of the first plurality of expanded image beams, reflect the first portion of the first plurality of expanded image beams within the leakage image pipe via one or more reflective surfaces of the leakage image pipe, and further provide the plurality of transmitted image beams to a second aperture expander via at least one partial reflective surface of the leakage image pipe, An optical system comprising: a second aperture expander disposed within the waveguide and configured to receive the second portion and the plurality of reflected image beams of the first plurality of expanded image beams, and further to provide a second plurality of expanded image beams that exit the waveguide through the rear surface.

17. The leak image pipe includes an output surface and an inner surface, The inner surface has a permeable coating that progresses continuously and progressively in the direction from the input surface to the output surface. The inner surface has a permeable coating that progresses discretely in the direction from the input surface to the output surface, or The optical system according to claim 16, wherein the inner surface has a uniform transparent coating.

18. The aforementioned leak image pipe is An outer surface having a mirror disposed perpendicular to the front surface, wherein the outer surface and the mirror are disposed on the side of the leak image pipe opposite to the second aperture expander, further comprising an outer surface, The optical system according to claim 16, wherein the input surface is perpendicular to the front surface and inclined at 20° to 160° with respect to the outer surface.

19. Waveguide, The front and rear surfaces are parallel to each other, A first aperture expander comprising a plurality of first partial reflective facets that are planar, disposed between the front and rear surfaces, parallel to each other and non-parallel to the front and rear surfaces, and configured to receive an input image beam and to provide a plurality of first expanded image beams that propagate and reflect between the front and rear surfaces, The first portion of the first plurality of partial reflection facets is configured to generate the first portion of the first plurality of extended image beams, A first aperture expander is configured such that a second portion of the first plurality of partial reflection facets generates a second portion of the first plurality of expanded image beams, A leak image pipe is configured to receive the first portion of the first plurality of expanded image beams, reflect the first portion of the first plurality of expanded image beams within the leak image pipe via one or more reflective surfaces of the leak image pipe, and further provide the plurality of transmitted image beams to a second aperture expander via at least one partial reflective surface of the leak image pipe. A waveguide comprising: a second aperture expander configured to receive the second portion of the first plurality of expanded image beams and the plurality of transmitted image beams, and further to provide a second plurality of expanded image beams that exit the waveguide through the rear surface.

Images