Waveguide with embedded leakage image conduit

Abstract

An optical device may include: a waveguide having a front surface and a parallel rear surface; a first aperture expander configured to receive the input image beam and provide a first plurality of expanded image beams, the first plurality of expanded image beams configured to propagate and reflect between the front surface and the back surface; a leak image conduit configured to receive a first portion of the first plurality of expanded image beams and 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 conduit; and a second aperture expander within the waveguide and configured to receive a second portion of the first plurality of expanded image beams and the plurality of transmitted image beams, the second aperture expander configured to provide a second plurality of expanded image beams, the second plurality of expanded image beams configured to exit through the back surface.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based upon and claims the benefit of priority under 35 U.S.C. 119(e) to U.S. patent application Ser. No. 63 / 459,727, filed on Apr. 17, 2023, and entitled “Embedded Light Guiding Slab,” the entire contents of which are hereby incorporated by reference herein in their entirety. Background Art

[0003] Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section. The present disclosure relates generally to optical devices and systems related to wearable devices used in augmented reality applications, and more particularly to improved wearable devices for providing optical information directly to a user.

[0004] Wearable optical devices used in augmented reality applications (e.g., near-eye displays or smart glasses) are often cumbersome to wear and use, limiting their comfort and practicality. Current wearable optical devices may also have a limited field-of-view (FoV), which may be undesirable for users and may affect safety in some cases. However, increasing the FOV often requires pushing geometric boundaries, which can be expensive and may result in product form factors and / or aesthetics that may not be acceptable in the market. What is needed are solutions that address these and other issues. Summary of the Invention

[0005] According to an example, an optical device is generally described. The optical device may include: a waveguide having a front surface and a 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 and provide a first plurality of expanded image beams, the first plurality of expanded image beams configured to propagate and reflect between the front surface and the rear surface; a leaky image conduit disposed within the waveguide and configured to receive a first portion of the first plurality of expanded image beams and 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 leaky image conduit; 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 the 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.

[0006] According to this example, in the optical device, the leakage image conduit includes an input face, an output face, and an inner surface, where there is one of: the inner surface has a continuous progressive transmissive coating in a direction from the input face to the output face; the inner surface has a discrete progressive transmissive coating in a direction from the input face to the output face; and the inner surface has a uniform transmissive coating. In the optical device, the first aperture expander can include a first plurality of angularly tilted partially reflective facets, and the first plurality of partially reflective facets is one of: tilted with respect to at least one of the front face and a plane perpendicular to the front face; and perpendicular to the front face. In this optical device, the input image beam is injected at the coupling region into the waveguide and propagates through the first aperture expander in a first direction away from the coupling region, and where there is at least one of: the reflectivity of the first plurality of partially reflective facets increases in the direction away from the coupling region; the reflectivity of the first plurality of partially reflective facets is constant in the direction away from the coupling region; the first aperture expander has a terminal facet that is a partially reflective facet; and the first aperture expander has a terminal facet that is a mirror. In the optical device, the leakage image conduit is an elongated member having orthogonal sides and a rectangular cross-section, and where the leakage image conduit has an outer surface that is at least one of: aligned perpendicular to the front face; not aligned perpendicular to the front face; aligned at an angle to a horizontal axis. In the optical device, the leakage image conduit can further include an outer surface having a mirror disposed on a side of the leakage image conduit opposite the second aperture expander.

[0007] According to this example, in the optical device, the leakage image conduit can further include: an outer surface; and an input face configured to receive a first portion of the first plurality of expanded image beams, the input face being perpendicular to the front face and tilted at an angle with respect to the outer surface in a range between 20° and 160°. In the optical device, the leakage image conduit is a first leakage image conduit, the plurality of reflected image beams is a first plurality of transmitted image beams directed through the first inner surface towards the second aperture expander, and the input face is a first input face, the optical device can further include: a second leakage image conduit disposed within the waveguide on a side of the second aperture expander opposite the first leakage image conduit, the second leakage image conduit configured to receive a third portion of the first plurality of expanded image beams and provide a second plurality of transmitted image beams directed through a second inner surface towards the second aperture expander, where the second aperture expander is configured to receive the first plurality of transmitted image beams, the 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 the back face.

[0008] According to the example, in the optical device, at least one of the first and second leaky image pipes is disposed at an angle to a horizontal axis of the waveguide. In the optical device, the second aperture expander includes a second plurality of partially reflective facets tilted at an angle that is at an inclination angle relative to at least one of a plane that is normal to the front surface and a plane that is normal to the front surface. In the optical device, the second portion of the first plurality of expanded image beams and the plurality of reflected image beams are directed to the eyebox. In the optical device, the waveguide further includes a partial plane reflector as a first uniformization layer disposed in a plane between the front surface and the back surface. In the optical device, the leaky image pipe further includes a second uniformization layer disposed in a plane between the front surface and the back surface of the leaky image pipe. In the optical device, the leaky image pipe further includes a third uniformization layer disposed in a plane between an inner surface and an outer surface of the leaky image pipe. In the optical device, the leaky image pipe further includes a fourth uniformization layer having a first portion disposed between the first aperture expander and the second aperture expander, the fourth uniformization layer having a second portion disposed between the leaky image pipe and the second aperture expander. The optical device can further include an image projector configured to produce a collimated image beam based on a digital image, wherein the collimated image beam is collimated to infinity, an input coupler configured to receive the input image beam and provide an output image beam that is injected into the waveguide at a coupling region, and a fifth uniformization layer disposed between the image projector and the input coupler.

[0009] According to another example, an optical system is generally described. The optical system can include: a waveguide having a front surface and a back surface parallel to each other; an image projector configured to produce a collimated image light beam based on a digital image, wherein the collimated image light beam is collimated to infinity; an input coupler configured to receive the collimated image light beam and output an input image light beam injected into the waveguide at a coupling region; a first aperture expander disposed within the waveguide and configured to receive the input image light beam and provide a first plurality of expanded image light beams configured to propagate and reflect between the front surface and the back surface; a leaky image pipe disposed within the waveguide and configured to receive a first portion of the first plurality of expanded image light beams and provide a plurality of transmitted image light beams, the first portion of the first plurality of expanded image light beams configured to partially reflect within the leaky image pipe, the leaky image pipe being an elongated member having orthogonal sides and a rectangular cross-section; and a second aperture expander disposed within the waveguide and configured to receive a second portion of the first plurality of expanded image light beams and the plurality of reflected image light beams, the second aperture expander configured to provide a second plurality of expanded image light beams configured to exit through the back surface.

[0010] According to the example, in the optical system, the leaky image pipe includes an input face, an output face, and an inner surface, and wherein as in one of: the inner surface has a continuous progressive transmissive coating in a direction from the input face to the output face; the inner surface has a discrete progressive transmissive coating in a direction from the input face to the output face; and the inner surface has a uniform transmissive coating. In the optical system, the first aperture expander includes a first plurality of partially reflective facets tilted at one of: an angle relative to at least one of the front surface and a plane perpendicular to the front surface; and perpendicular to the front surface; and wherein the second aperture expander includes a second plurality of partially reflective facets tilted at an angle that is at an oblique angle relative to at least one of the front surface and a plane perpendicular to the front surface. In the optical system, the leaky image pipe can further include: an outer surface having a mirror disposed perpendicular to the front surface, the outer surface and the mirror disposed on an opposite side of the leaky image pipe from the second aperture expander; and the input face configured to receive the first portion of the first plurality of expanded image light beams, the input face being perpendicular to the front surface and tilted at an angle relative to the outer surface ranging between 20° and 160°.

[0011] The foregoing summary is illustrative only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, other aspects, embodiments, and features will become apparent by reference to the accompanying drawings and the following detailed description. In the accompanying drawings, the same reference numerals indicate the same elements or functionally similar elements. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 Block diagrams of optical systems according to various examples of the present disclosure are shown.

[0013] Figure 2A Shown are front plan views of optical systems including waveguides according to various examples.

[0014] Figure 2B Various examples are shown including Figure 2A Side plan view of the waveguide optical system.

[0015] Figure 3A Shown are front plan views of optical systems including waveguides according to various examples.

[0016] Figure 3B Various examples are shown including Figure 3A Side plan view of the waveguide optical system.

[0017] Figure 4 Shown are front plan views of optical systems including waveguides according to various examples.

[0018] Figure 5 Shown are front plan views of optical systems including waveguides according to various examples.

[0019] Figure 6 Shown are front plan views of optical systems including waveguides according to various examples.

[0020] Figure 7 Shown are front plan views of optical systems including waveguides according to various examples.

[0021] Figure 8 Shown are front plan views of optical systems including waveguides according to various examples.

[0022] Figure 9 Shown are front plan views of optical systems including waveguides according to various examples.

[0023] Figure 10 Shown are front plan views of optical systems including waveguides according to various examples.

[0024] Figure 11 Shown are front plan views of optical systems including waveguides according to various examples.

[0025] Figure 12 A front plan view of an optical system including a waveguide is shown in accordance with various examples. DETAILED DESCRIPTION

[0026] In the following description, numerous specific details are set forth such as particular structures, components, materials, dimensions, processing steps and techniques in order to provide an understanding of the various embodiments of the present application. However, it will be appreciated by one of ordinary skill in the art that the various embodiments of the present application can be practiced without these specific details. In other instances, well-known structures or processing steps have not been described in detail in order to avoid obscuring the application.

[0027] As will be described in greater detail below, wearable devices such as near-eye displays and / or smart glasses can be implemented by systems and methods in accordance with the present disclosure. The systems can efficiently provide high quality optical information to a user in a variety of applications.

[0028] Figure 1 A block diagram of an optical system in accordance with various examples of the present disclosure is shown. The optical system 100 can include two or more devices or components. The optical system 100 can be implemented generally as a hybrid system including various electronic, optical, and electro-optical elements. The optical device 102 can include one or more elements from the optical system 100. As will be described in greater detail below, the optical system 100 can include a wearable device 110 such as one or more near-eye displays or smart glasses that can be worn on or around a user's head to deliver optical information to one or both eyes of the user.

[0029] The wearable device 110 can include a controller 114 having a memory 116, where the controller 114 can be configured, for example, to send and receive electrical signals to and from various other elements in the optical system 100, to execute program instructions stored in the memory 116 to process and provide information, to operate the wearable device 110, and to interact with other systems external to the wearable device 110. The controller 114 can include a microcontroller, a processor, various discrete components, programmable logic devices, and / or various interface circuitry that can access the memory 116, which can be removable, replaceable, programmable, and reprogrammable to update instructions to the controller 114.

[0030] The wearable device 110 can also include a power management module 120 having a battery 122, where the power management module 120 can be configured to charge, discharge, and monitor power usage of the battery 122. Various elements of the wearable device 110, including the controller 114, the image projector 126, and the optical engine 134, for example, can receive power from the battery 122. The wearable device 110 can also include one or more image projectors 126, each configured to produce a collimated image light beam based on a digital image 128. The collimated image light beam can be an illuminated representation of a digital image having an image field that is a two-dimensional representation of a digital image based on a single graphical image (e.g., a still image) or a sequence of graphical images (e.g., a moving image). The collimated image light beam can be collimated to infinity.

[0031] The wearable device 110 can also include one or more waveguides 130 (e.g., WGs, also denoted as light-guide optical elements, LOEs) including a transparent material configured to receive and propagate light, where the light can be incident and emergent through various external and internal surfaces of the waveguide 130. For example, the transparent material included by the waveguide 130 can include optical glass or other suitable materials that are transformed into complex optical structures using processes that can include coating, stacking, slicing, polishing, and shaping the transparent material. For example, the processes can include adding partially reflective or fully reflective materials (e.g., mirror coatings). Similarly, for example, the processes can also include adding partially opaque or fully opaque materials (e.g., light covers to block light).

[0032] The wearable device 110 can also include one or more optical engines 134 coupled to the one or more image projectors 126 and the waveguide 130. The optical engine 134 can be configured to directly operate the image projector 126 under the direction of the controller 114. For example, the optical engine 134 can provide graphical processing for the digital image 128 prior to the illuminated representation of the digital image being projected by the image projector 126.

[0033] The wearable device 110 may also include a frame 138 (e.g., a structure) for supporting and holding one or more elements of the wearable device 110. For example, the frame 138 may support the first image projector 126 and hold the first image projector in a position close to the first waveguide 130. Similarly, the frame 138 may support the second image projector 126 and hold the second image projector in a position close to the second waveguide 130. In this manner, for example, the frame 138 may support one or two image projector 126 and waveguide 130 pairs and hold one or two image projector and waveguide pairs on or around the user's head. References herein are made to the orientation of various elements relative to each other. As described in the relevant figures, such references may also include references to various elements of the wearable device 110 when supported by the frame 138, or to various elements of the wearable device 110 with respect to three-dimensional (3D) coordinates (e.g., X-axis, Y-axis, Z-axis).

[0034] 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 some instructions provided to the controller 114 and stored in the memory 116. The host computer 170 may communicate with one or more elements of the wearable device 110 via a signal and power bus 188. In this manner, the host computer 170 may provide power to charge the battery 122, provide instructions to and receive status from the controller 114 to control various other elements of the wearable device 110, and provide digital image data to the optical engine 134.

[0035] Figure 2A Shown are front plan views of optical systems including waveguides according to various examples. Figure 2B Various examples are shown including Figure 2A Further reference is made to the side plan view of the optical system of the waveguide. Figure 1 and Figure 2A to Figure 2B ,These Figure 1An optical system 100 (with optical device 102) in a first configuration is shown, which can include a waveguide 130 (WG 130) having a front surface 202 and a back surface 204 that are parallel to each other. An image projector 126 can be configured to produce a collimated image light beam 290 based on a digital image 128, where the collimated image light beam can be collimated to infinity. The collimated image light beam can be an illuminated representation of the digital image having an image field that is a two-dimensional representation of the digital image based on a single graphical image (e.g., a still image) or a sequence of graphical images (e.g., a moving image). An input coupler 292 can be configured to receive the collimated image light beam 290 and output an input image light beam 212 that is injected into the waveguide 130 at a coupling region 248. Although Figure 2A A gap between the image projector 126 and the input coupler 292 is shown, but such a gap is for illustrative purposes and can not be present in actual implementations for the present example and other examples.

[0036] A first aperture expander 208 can be disposed within the waveguide 130 and configured to receive the input image light beam 212 that is internally reflected coupled and provide a first plurality of expanded image light beams 216 that are expanded in a first dimension. The first plurality of expanded image light beams 216 can be configured to propagate and reflect between the front surface 202 and the back surface 204 (e.g., an external surface). The first aperture expander 208 can include a first plurality of angled tilted, mutually parallel, and partially reflective optical elements 242 (e.g., facets or internal surfaces) that are tilted at an angle that is one of: at an oblique angle with respect to at least one of the front surface 202 and a plane 206 (e.g., an X-Z plane) that is perpendicular to the front surface; and perpendicular to the front surface (e.g., the plane 206). As will be more fully described below, various coupling means for the input image light beam 212 can be used, including mirrors, optical couplers, and other mechanisms. More generally, the input image light beam 212 can be in-coupled into the waveguide 130 (e.g., a substrate) and the first aperture expander 208 by internal reflection.

[0037] As described, partial reflection can mean partial transmission such that some portions of the illumination incident on a particular facet can be reflected while the rest can be transmitted through the facet, which results in the first set of planar, mutually parallel, and partially reflective facets 242 starting with an initial facet 244 at the beginning of the first etendue expander 208 and extending all the way to a penultimate facet 256 and a final (e.g., terminating) facet 258 at the end of the first etendue expander 208, where the illumination travels in a direction 252 from the initial facet 244 to the small end facet 258 along the first etendue expander 208. Thus, the input image beam 290 can be injected at the coupling region 248 and propagate through the first etendue expander 208 in the first direction 252 away from the coupling region 248.

[0038] In one example, the reflectivity of the first plurality of partially reflective facets 242 can increase in the direction away from the coupling region 248 to compensate for the reduced illumination that is transmitted by previous facets and eventually reaches the small end facet 258, which can be a mirror that only reflects the illumination and does not transmit the illumination through the mirror. Alternatively, the reflectivity of the first plurality of partially reflective facets 242 can be constant in the direction away from the coupling region 248 until reaching the small end facet 258, which can be a mirror. For example, when the reflectivity of the facets is constant, each facet can have the same applied coating. In another alternative, the small end facet 258 can have the same (e.g., uniform) partial reflectivity as the other partially reflective facets 242, or the small end facet 258 can have a wedge-like configuration in various applications. In this case, the small end facet 258 can not be a full mirror, but can instead be a partially reflective element, e.g., a partially reflective facet, a wedge, etc.

[0039] The leaky image pipe 220 can be disposed within the waveguide 130 and can be configured to receive the first portion 224 of the first plurality of expanded image beams and provide a plurality of transmitted image beams 228. In this sense, the leaky image pipe 220 can be considered as embedded in the waveguide 130. The leaky image pipe 220 can have the same or a different index of refraction compared to other components in the waveguide 130. The first portion 224 of the plurality of expanded image beams 216 can be configured to partially reflect and propagate within the leaky image pipe 220. In this way, the beams can be transmitted through an inner surface 262 of the leaky image pipe 220 along a path of light propagation to expand the first portion 224 by partial reflection and transmission of the image beams 228 within the leaky image pipe 220 through partial transmission of the inner surface 262, thereby avoiding the need for more partially reflecting facets 242 that would result in a longer (e.g., taller) first aperture expander 208. In this way, the leaky image pipe 220 can transmit, reflect, and reposition (e.g., tunnel) light rays from farther away. For example, expanding the first portion 224 with the leaky image pipe 220 can result in a smaller waveguide with the same or better performance compared to a larger waveguide with more partially reflecting facets. The leaky image pipe 220 can be an elongated member with orthogonal sides and a rectangular cross-section, thus having opposing and parallel surfaces configured to maintain a light ray propagation angle. In this way, the leaky image pipe 220 can have opposing sides parallel to each other, which generally have a rectangular cross-section or, in one particular example, a square cross-section.

[0040] Further, the reflective walls of the leaky image pipe 220 can be orthogonal to the major surfaces of the waveguide 130. In this way, any light rays coupled into the leaky image pipe 220 can be coupled out of the leaky image pipe 220 with the exact same propagation angle. The leaky image pipe 220 can be coated with various optical coatings, e.g., varying reflective coatings, dielectric reflective coatings, highly reflective coatings, etc. The leaky image pipe 220 can include an outer surface 260 that can be aligned or disposed parallel to a plane 206 normal to the front surface 202, which corresponds to, for example, two of the three principal axes (e.g., the X-Z plane) that 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 leaky image pipe 220 can also be angularly aligned or disposed with the horizontal axis 210. Thus, as described, the leaky image pipe 220 can be oriented in at least one of the following: oriented normal to the front surface 202, oriented non-normal to the front surface 202, and oriented angularly to the horizontal axis 210.

[0041] The outer surface 260 of the leaky image pipe 220 can also include a mirror 274 (e.g., a mirror coating) that reflects illumination only within the leaky image pipe 220 without transmitting light through the outer surface 260. In this way, illumination reflected within the leaky image pipe 220 can be transmitted through the inner surface 262 of the leaky image pipe 220. More specifically, a first portion 224 of the first plurality of expanded image beams 216 can enter an input face 264 (e.g., an input aperture 264) of the leaky image pipe 220 and can propagate as a plurality of reflected beams 230, where some portions of the reflected beams 230 can be transmitted through the inner surface 262. Although the input aperture 264 can be described for convenience as an input face 264, the input aperture 264 can be practiced in a variety of ways. For example, the leaky image pipe 220 can be formed from an initial transparent plate having a refractive index that is the same or different from the rest of the waveguide 130. In this example, the leaky image pipe 220 having a different refractive index can have an actual entrance aperture that can have an optically polished surface. Alternatively, when the leaky image pipe 220 has the same refractive index as the other components of the waveguide 130, the input aperture 264 can be implemented as parallel but laterally separated coatings. As described, the input face 264 can be perpendicular to the front surface 202 and angularly tilted with respect to the outer surface 260, which can be in a range between 20° and 160°, and can preferably be in a range between 35° and 150°, and can generally be about 90°. In this way, the input face 264 can form an angle with the illumination from the first aperture expander 208, where the angle can range from an acute angle (e.g., angled away from the first aperture expander 208 to capture less illumination) or an obtuse angle (e.g., angled toward the first aperture expander 208 to capture more illumination). In this way, the angle of the input face 264 (e.g., the entrance pupil) can be used to set or control the amount of illumination captured by the leaky image pipe 220 to balance the illumination level within the waveguide 130, for example, to set the effective aperture seen from the object side. For completeness, some portions of the reflected beams 230 can exit through an output face 266 of the leaky image pipe 220, which can be negligible. Likewise, depending on the implementation, the output face 266 can not be an optically polished surface. Instead, as described, the output face 266 can correspond to an end region of parallel but laterally separated coatings. In some examples, the lateral separation can be important, where some portions of the coating can be omitted when the transmitted and reflected light of the leaky image pipe 220 can not reach the eyebox 276 and the user’s eye. For example, for regions of the leaky image pipe 220 that do not need to reflect image beams to the eyebox 276, the mirror coating 274 on the outer surface 260 of the leaky image pipe 220 can be omitted.For example, this can benefit both by saving the cost of applying a mirror coating to a portion of the application and by no longer unnecessarily obscuring the user's view through the non-mirror portion of the waveguide 130.

[0042] A second aperture expander 232 can be disposed within the waveguide 130 and configured to receive the second portion 236 of the first plurality of expanded image light beams 216 and the plurality of transmitted image light beams 228. Similar to the first aperture expander 208 in certain aspects, the second aperture expander 232 can include a second plurality of partially reflective facets 272 tilted at an angle that can be at an oblique angle with respect to at least one of the front surface 202 and a plane 206 normal to the front surface (e.g., the X-Z plane). As described, both the second portion of the first plurality of expanded image light beams 216 and the plurality of transmitted image light beams 228 can be directed to the second aperture expander 232, where a second plurality of expanded image light beams 240 can be directed, for example, toward the user's eye adjacent an eyebox 276. Thus, the second aperture expander 232 can be configured to provide the second plurality of expanded image light beams 240 configured to exit through (e.g., transmitted through) the back surface 204. In this way, the first aperture expander 208 and the second aperture expander 232 can cooperate to expand versions of the collimated image light beams 290 in two dimensions (2D), resulting in a two-dimensional expansion of the input image light beams 290 to the out-coupling region of the waveguide 130 (also described as the eyebox 276) and configured to exit through the back surface 204 toward the user's eye 280.

[0043] Various light homogenizers (e.g., partially reflective uniformization layers) can also be used, alone or in combination, to provide improved image intensity uniformity, among other benefits. For example, as Figure 2BAs shown, the waveguide 130 can include a partial planar reflector as the first uniformization layer 284, where the partial planar reflector as the first uniformization layer 284 can be disposed in a plane between the front surface 202 and the back surface 204. The waveguide 130 can also include a second uniformization layer 286 disposed in a plane between the front surface 268 and the back surface 270 of the leaky image pipe 220. In this way, the second uniformization layer 286 can be oriented vertically to uniformize light based on horizontal reflections. The leaky image pipe 220 can also include a third uniformization layer 288 disposed in a plane between the inner surface 262 and the outer surface 260 of the leaky image pipe 220. In this way, the third uniformization layer can be oriented horizontally to uniformize light based on vertical reflections. The third uniformization layer 288 can be a semi-reflective surface (e.g., a film disposed parallel to a reflective wall of the leaky image pipe) added within the leaky image pipe 220 to, for example, fill one or more empty panel apertures. As described, the first portion 224 of the first plurality of expanded image beams 216 can enter the leaky image pipe 220 at the entrance aperture 264 and be partially reflected by the third uniformization layer 288 and partially transmitted and then partially reflected by the inner side of the leaky image pipe 220 inner surface 262. When the second uniformization layer 286 is present, the second uniformization layer can double the light beams by reflecting and propagating horizontally within the leaky image pipe 220. When the third uniformization layer 288 is present, the third uniformization layer can double the light beams by reflecting and propagating vertically within the leaky image pipe 220. This description also applies to other uniformizers disclosed herein.

[0044] Due to the illumination propagation 230 in the leaky image pipe 220, the eyebox 276 can be properly illuminated, increasing the field of view (FoV) of the user, avoiding the need for larger optics, reducing the size, reducing the weight, and reducing the cost. As described, Figure 2A to Figure 2B An optical system 100 (with optics 102) in a first configuration is shown, where, as described, the second aperture expander 232 can be tilted towards the first aperture expander 208 and the leaky image pipe 220 can be disposed vertically below the second aperture expander 232, or the second aperture expander 232 is disposed on top of the leaky image pipe 220 (e.g., light guide plate). This should not be considered limiting. In this example and others, the waveguide 130 can be rotated in a plane or flipped around a central or diagonal axis without departing from the present disclosure.

[0045] Figure 3A A front view planar view of an optical system including a waveguide according to various examples is shown. Figure 3B A front view planar view of an optical system including a waveguide according to various examples is shown. Figure 3Aside view plan view of the optical system of the waveguide. Further reference is made to Figure 1 and Figure 2A to Figure 2B These Figure 1 illustrates the optical system 100 (with the optical arrangement 102) in a second configuration, in which the second aperture expander 232 can be tilted towards the first aperture expander 208, and the leaky image conduit 220 can be disposed vertically above the second aperture expander 232. In this way, Figure 3A to Figure 3B the illustration of this second configuration in Figure 2A to Figure 2B can be considered as being vertically "flipped" with reference to the illustration of the above-described Figure 2A to Figure 2B This should not be considered limiting, and references such as the outer surface 260 and the inner surface 262 can be readily understood as relative terms, which can also be identified as a first surface 260 and a second surface 262 disposed opposite the first surface 260, and vice versa, without departing from the present disclosure. As with the dimensions, weight, and cost savings illustrated by the example of Figure 3A to Figure 3B the example of Figure 2A likewise illustrates a possible relative size reduction, for example, as compared to a larger waveguide 330 having a larger profile and increased height 332 as compared to

[0046] Figure 4 illustrates a front view plan view of the optical system including the waveguide according to various examples. Based on Figure 2A to Figure 2B the foregoing description of Figure 4 the example illustrated in Figure 2A the input face 264 can be perpendicular to the front surface 202, and tilted at an angle that can be in a range between 20° and 160° with respect to the outer surface 260. In this example, the input face 264 can form an acute angle (e.g., angled away from the first aperture expander 208 to capture less illumination and reflect more illumination), as described. The input face 264 can be angled the same (e.g., same direction and same angle) as the output face 266, but this should not be considered limiting. In certain aspects similar to Figure 3A and Figure 4A plurality of representative ghost reflected image light beams corresponding to the transmitted image light beams 228 from the leakage image pipe 220 are shown as if the corresponding transmitted image light beams were reflected off of the partially-reflecting facet in the representation of the extended first aperture expander 208 having an increased number of partially-reflecting facets. In this way, the use of the leakage image pipe 220 can allow for a reduction in the size and / or profile of the waveguide 130, causing the waveguide to be implemented as a smaller waveguide 430 having a reduced height 432.

[0047] Figure 5 A front plan view of an optical system including a waveguide according to various examples is shown. Referring to Figure 1 and Figure 2A to Figure 2B and Figure 5 The optical device 102 can include a leakage image pipe 220 that can have an outer surface 260 that can not be oriented normal to the front surface 202. Alternatively, for example, the outer surface 260 can be rotated about the horizontal axis 210 such that the outer surface 260 is angled to reflect illumination toward the back surface 204 and the second aperture expander 232. Alternatively, for example, the outer surface 260 can be rotated about the horizontal axis 210 such that the outer surface 260 is angled to reflect illumination toward the front surface 202, where the illumination directed toward the front surface 202 can reflect back toward the second aperture expander 232. In this way, the leakage image pipe 220 can receive the first portion 224 of the first plurality of expanded image light beams 216 and the at least one more light beam 524 at the entrance aperture 264, such that both the first portion 224 and the at least one more light beam 524 can reflect and propagate within the leakage image pipe 220. In this way, the first portion 224 can provide transmitted light beams 228 that can be transmitted through the inner surface 262 toward the eyebox 276 and reflected light beams 230 within the leakage image pipe 220. Similarly, as described above, the at least one more light beam 524 can provide transmitted light beams 528 that can be transmitted through the inner surface 262 toward the eyebox 276 and at least one reflected light beam 530 that can reflect within the leakage image pipe 220. Although Figure 5 and elsewhere only representative light beams are shown, it can be understood that many other image light beams will be received, transmitted, reflected, and propagated in actual implementations.

[0048] Figure 6 A front plan view of an optical system including a waveguide according to various examples is shown. In certain aspects similar to Figure 2A to Figure 2B the examples shown, Figure 6A waveguide 130 is shown with a separation distance 602 between the first aperture expander 208 and the second aperture expander 232, where the separation distance 602 provides a gap between the first aperture expander 208 and the second aperture expander 232 that can be used, for example, to place the eyebox 276 further away from the first aperture expander.

[0049] Figure 7 A front view planar diagram of an optical system including a waveguide is shown, according to various examples. In certain aspects, the example shown is similar to the example shown above Figure 2A to Figure 2B and Figure 6 the example shown above, Figure 7 A waveguide 130 is shown with a separation distance 702 between the first aperture expander 208 and the second aperture expander 232, where the separation distance 702 can be less than the distance 602 due to the addition of a fifth uniformization layer 794 (e.g., a fifth hybridizer 794) disposed between the image projector 126 and the input coupler 292, where this configuration can enable a smaller form factor by pre-uniformizing the image beam, thereby enabling a reduction in the separation distance between the first aperture expander 208 and the second aperture expander 232 such that the leaky image conduit 220 can be juxtaposed adjacent to facets of the first aperture expander 208. In contrast, Figure 7 the configuration shown in the example above can provide a more compact (e.g., smaller) waveguide 130 based on a relatively smaller separation distance 702 to reduce the gap between the first aperture expander 208 and the second aperture expander 232, which can be used, for example, to place the eyebox 276 closer to the first aperture expander 208, thereby enabling a smaller profile of the waveguide 130.

[0050] Figure 8 A front view planar diagram of an optical system including a waveguide is shown, according to various examples. In certain aspects, the example shown is similar to the example shown above Figure 2A to Figure 2B and Figure 8An example of a leaky image conduit 220 is shown that includes an input face 264, an output face 266, and an inner surface 262 (e.g., a transmissive surface in which reflected image beams can exit), which can have a coating 802 that uniformly transmits across the surface with the same transmissivity, or the inner surface 262 can have a progressive transmissive coating applied in a direction from the input face 264 to the output face 266. In this sense, the inner surface 262 can have a uniformly transmissive coating. As described, the progressive transmissive coating can allow an increasing amount of illumination to be transmitted through the inner surface 262 based on increasing linear distance from the input face 264. In other words, the coating 802 can be less reflective, allowing a greater proportion of light energy to be transmitted through the inner surface 262 based on distance from the input face 264. The increased transmissivity (corresponding to decreased reflectivity) of the coating 802 can follow a gradient or continuous, gradual slope of higher reflectivity at the input face 264 toward lower reflectivity at the output face 266. In this sense, the inner surface 262 can have a continuously progressive transmissive coating in a direction from the input face 264 to the output face 266. Alternatively, the transmissive coating 802 can include a discrete, stepwise, or stair-step increase in transmissivity (e.g., or a corresponding discrete or stepwise decrease in reflectivity) 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 that directs toward a mirror 274 on an interior region of the leaky image conduit 220 and an outer surface 260 to form the input aperture 264 such that no illumination can be transmitted through the first coating region 804. Next, the progressive transmissive coating 802 can include a second coating region 806 at a second linear distance that is more transmissive than the mirror coating on the portion of the inner surface corresponding to the first coating region 804. Similarly, the progressive transmissive coating 802 can include a third coating region 808 at a third linear distance that is even less reflective and more transmissive. This pattern can continue such that a fourth coating region 810 is more transmissive than the third coating region 808 but less transmissive than a fifth coating region 812. Finally, a sixth coating region 814 can be the most transmissive region in the progressive transmissive coating 802 to allow any remaining illumination (if not already depleted) to be transmitted through the inner surface 262. In this sense, the inner surface 262 can have a discrete progressive transmissive coating in a direction from the input face 264 to the output face 266. In this way, the amount of illumination provided by the reflected image light within the leaky image conduit 220 can be controlled and balanced prior to coupling to the out-coupling region of the eyebox 276. The progressive transmissive coating 802 can be applied as multiple applications of the same reflective and / or transmissive material to achieve greater reflectivity and lower transmissivity, or different coating materials can be used for each region.The penultimate facet 256 and the final (e.g., terminal) facet 258 at the end of the first aperture expander 208 can similarly include facet 256 having a greater reflectivity and a lower transmittance than facet 258 to ensure that a maximum amount of illumination is redirected to the leakage image conduit 220. In this example, the coating forming the outer surface 260 can be shortened (e.g., omitted at an initial portion) to enable filling of the input aperture 264. Although these terms may be used together, the input aperture 264 can also be defined as the vertical region between the inner surface 262 and the outer surface 260 that is adjacent to the portion of the leakage image conduit 220 to the left of where the mirror coating 274 of the outer surface 260 begins (as described).

[0051] As described, image illumination can be injected into the leaky image conduit 220 to fill the first face 264. In one example, using only a single reflective coating can generate uneven illumination within the eye box 276. To address this issue, multiple or different coatings can be used whose reflectivity is reduced in the outcoupling region of the eye box 276 (e.g., fewer layers of resistive or reflective coating, and thus increased transmission), thereby achieving more uniform illumination across the eye box 276. Corresponding highly reflective coatings can be added to the first aperture expander facets 256 and 258 to ensure that sufficient optical power is injected into the leaky image conduit 220, thereby achieving more uniform illumination.

[0052] Figure 9 A front plan view of an optical system including a waveguide according to various examples is shown. Figure 2A to Figure 2B The example shown is similar to Figure 9 An example of a leaky image duct 220 aligned with the horizontal axis 210 at an angle 902 is shown. Angle 902 can provide more freedom to optical designers by providing more flexibility in the design of various coatings, as well as improving area usage (e.g., freeing up a portion of the waveguide 130 that may have previously been covered by a portion of the leaky image duct 220 in a horizontal orientation). Angle 902 can vary between 0° and 30°, and preferably, between 15° and 20°.

[0053] Figure 10 A front plan view of an optical system including a waveguide according to various examples is shown. Figure 2A to Figure 2B The example shown is similar to Figure 10An example of a leaky image conduit 220 that is significantly shorter and laterally displaced is shown, and is disposed relatively close to the first aperture expander 208 and relatively far from the second aperture expander 232. As described above, illumination (e.g., illumination transmitted through the inner surface 262) exiting the leaky image conduit 220 can illuminate corner regions of the eyebox 276 to provide illumination through the spaced apart or expanded transmitted image beam 228 as described above. Figure 10 A profile 1002 that can indicate an outline of a sketch of a waveguide (WG) for use in a fashion eyeglass frame is also shown. In this way, the leaky image conduit 220 can be at least partially hidden within a portion of the frame 138 that supports the waveguide 130, for example.

[0054] Figure 11 A front plan view of an optical system including a waveguide is shown, according to various examples. In certain aspects similar to the examples of Figure 10 The example of Figure 11 The example of includes the addition of a uniformization layer 1102 having a first portion 1104 disposed between the first aperture expander 208 and the second aperture expander 232 and a second portion 1106 disposed between the leaky image conduit 220 and the second aperture expander 232. The uniformization layer 1102 can be considered an L-shaped uniformization region, which can be a combination of the first uniformization region 1104 and the second uniformization region 1106, connected as a single continuous portion of the partially reflective layer (e.g., parallel to the front surface 202), or as an assembly of two or more regions, to provide additional uniformization of the first plurality of expanded image beams 216 and to provide a mix of illumination (radiation) directly from the first aperture expander 208 in the uniformization layer region 1104 and illumination propagating from the leaky image conduit 220 in the uniformization layer region 1106.

[0055] Figure 12 A front plan view of an optical system including a waveguide is shown, according to various examples. In certain aspects similar to the descriptions of the various examples above, Figure 12An example waveguide 130 is shown as oriented vertically as described, having a first leaky image pipe 220 disposed on a first side (e.g., a bottom side) of a second aperture expander 232 and a second leaky image pipe 1220 disposed on a second side (e.g., a top side) of the second aperture expander 232. As described, a first portion 224 of the first plurality of expanded image beams 216 from the first aperture expander 208 can enter a first entrance aperture 264 to be partially transmitted as a plurality of first transmitted image beams 228 through a first inner surface 262 of the first leaky image pipe 220 disposed adjacent to the bottom side of the second aperture expander 232. The inner surface 262 can have a coating 802 that is one of: a continuous gradual transmission coating, a discrete gradual transmission coating, and a uniform transmission coating in a direction from the input face 264 to the output face 266. In this way, the first portion 224 of the first plurality of expanded image beams 216 can exit the first leaky image pipe as expanded beams toward the second aperture expander 232. The first portion 224 of the first plurality of expanded image beams 216 can be partially reflected as a plurality of first reflected image beams 230 within the first leaky image pipe 220 that reflect within the first leaky image pipe 220 from an inner side of a first outer surface 260 disposed on a side of the first leaky image pipe 220 distal to the second aperture expander 232. Similarly, as described, a third portion 1224 of the first plurality of expanded image beams 216 from the first aperture expander 208 can enter a second entrance aperture 1264 to be partially transmitted as a plurality of second transmitted image beams 1228 through a second inner surface 1262 of the second leaky image pipe 1220 disposed adjacent to the top side of the second aperture expander 232. As previously described, the inner surface 1262 can have a coating 1296 that is one of: a continuous gradual transmission coating, a discrete gradual transmission coating, and a uniform transmission coating in a direction from the input face 1264 to the output face 1266. In this way, the third portion 1224 of the first plurality of expanded image beams 216 can exit the second leaky image pipe as expanded beams toward the second aperture expander 232. The third portion 1224 of the first plurality of expanded image beams 216 can be partially reflected as a plurality of reflected image beams 1230 within the second leaky image pipe 1220 that reflect within the second leaky image pipe 1220 from an inner side of a second outer surface 1260 disposed on a side of the second leaky image pipe 1220 distal to the second aperture expander 232. For example, as referenced Figure 2A and Figure 3AThe remaining portion of the expanded image beams 216 can be combined with the first plurality of transmitted image beams 228 and the second plurality of transmitted image beams 1228 and applied to the second aperture expander 232 and directed toward the eyebox 276 to the user’s eye. 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 back surface 204. In this example, the first and second leakage image pipes 220, 1220 can receive and process opposite beam directions to avoid generating ghost images.

[0056] Various features described above individually can be combined together unless they are incompatible with each other. For example, Figure 12 Either or both of the first and second leakage image pipes 220, 1220 illustrated in the examples above can be replaced by a leakage image pipe 220 aligned with the horizontal axis 210 at an angle 902 as described above with reference to Figure 9 Additionally, either or both of the first and second leakage image pipes 220, 1220 can include one or more uniformizers such as the uniformization layer 286 and the uniformization layer 288 described above with reference to Figure 2A to Figure 2B

[0057] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present invention. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “includes,” “comprises,” and / or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Moreover, terminology such as top, bottom, vertical, horizontal, front, back, inner, outer, and the like can describe the relative positioning of elements in a particular view shown in the drawings and should not be viewed as limiting. Such terminology can be applied in reverse when the view or elements are reversed.

[0058] ​The corresponding structures, materials, acts, and equivalents of all means or step plus function elements (if any) in the claims that follow, are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present application has been presented for purposes of illustration and description, but is not intended to be exhaustive or to limit the application to the precise form disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to best explain the principles of the application and its practical application, and to thereby enable others skilled in the art to best utilize the application in various embodiments and with various modifications as are suited to the particular use contemplated.

Claims

1. An optical device comprising: a waveguide having a front surface and a rear surface that are parallel to each other; a first aperture expander disposed within the waveguide and configured to receive an input image beam and provide a first plurality of expanded image beams configured to propagate and reflect between the front surface and the rear surface; a leakage image conduit disposed within the waveguide and configured to receive a first portion of the first plurality of expanded image beams and provide a plurality of transmitted image beams, the first portion of the first plurality of expanded image beams being configured to be partially reflected within the leakage image conduit; as well as a second aperture expander disposed within the waveguide and configured to receive a second portion of the first plurality of expanded image beams and the 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.

2. The optical device according to claim 1, wherein The leakage image pipeline includes an input surface, an output surface, and an inner surface, wherein one of the following exists: The inner surface has a continuous progressive transmission coating in a direction from the input face to the output face; The inner surface has a discrete progressive transmission coating in a direction from the input face to the output face; as well as The inner surface has a uniform transmissive coating.

3. The optical device according to claim 1, in, The first aperture expander comprises a first plurality of partially reflective facets, the first plurality of partially reflective facets being tilted at an angle, and the first plurality of partially reflective facets being one of: inclined relative to at least one of the front surface and a plane perpendicular to the front surface; and perpendicular to the front surface.

4. The optical device according to claim 3, in, The input image beam is injected into the waveguide at a coupling region and propagates through the first aperture expander in a first direction away from the coupling region, and wherein at least one of the following exists: a reflectivity of the first plurality of partially reflective facets increasing in a direction away from the coupling region; a reflectivity of the first plurality of partially reflective facets being constant in a direction away from the coupling region; The first aperture expander has a facet that is a partially reflective facet; and The first aperture expander has a small end face serving as a reflecting mirror.

5. The optical device according to claim 1, in, The leakage image duct is an elongated member having orthogonal sides and a rectangular cross-section, and The leakage image pipe has an outer surface, and the outer surface is at least one of the following: aligned perpendicular to said front surface; aligned non-perpendicularly to the front surface; and Aligned at an angle to the horizontal axis.

6. The optical device according to claim 5, wherein The leaked image pipeline also includes: An outer surface having a reflective mirror is disposed on a side of the leakage image conduit opposite to the second aperture expander.

7. The optical device according to claim 1, wherein The leaked image pipeline also includes: External surface; and An input face configured to receive the first portion of the first plurality of expanded image beams, the input face being perpendicular to the front surface and inclined relative to the exterior surface at an angle ranging between 20° and 160°.

8. The optical device according to claim 1, wherein The leakage image conduit is a first leakage image conduit, the plurality of reflected image light beams are a first plurality of transmitted image light beams transmitted through the first inner surface and directed toward the second aperture expander, and the input surface is a first input surface, the optical device further comprising: a second leakage image conduit disposed within the waveguide on an opposite side of the second aperture expander from the first leakage image conduit, the second leakage image conduit being configured to receive a third portion of the first plurality of expanded image beams and provide a second plurality of transmitted image beams directed toward the second aperture expander through a second inner surface, wherein the second aperture expander is configured to receive the first plurality of transmitted image beams, the second plurality of transmitted image beams, and the second portion of the first plurality of expanded image beams, and provide a second plurality of expanded image beams configured to exit through the rear surface.

9. The optical device according to claim 8, wherein At least one of the first leakage image conduit and the second leakage image conduit is disposed at an angle to a horizontal axis of the waveguide.

10. The optical device according to claim 1, in, The second aperture expander includes a second plurality of partially reflective facets tilted at an oblique angle relative to at least one of the front surface and a plane perpendicular to the front surface.

11. The optical device according to claim 1, wherein The second portion of the first plurality of expanded image beams and the plurality of reflected image beams are directed to an eye box.

12. The optical device according to claim 1, wherein The waveguide further comprises a partially planar reflector as a first uniformizing layer disposed in a plane between the front and rear surfaces.

13. The optical device according to claim 1, wherein The leakage image conduit further includes a second uniformization layer disposed in a plane between the front and rear surfaces of the leakage image conduit.

14. The optical device according to claim 1, wherein The leakage image tube further includes a third uniformization layer disposed in a plane between the inner and outer surfaces of the leakage image tube.

15. The optical device according to claim 1, wherein The leakage image pipe also includes a fourth uniformization layer having a first portion disposed between the first aperture expander and the second aperture expander, the fourth uniformization layer having a second portion disposed between the leakage image pipe and the second aperture expander.

16. The optical device according to claim 1, further comprising: an image projector configured to generate a collimated image beam based on a digital image, wherein the collimated image beam is collimated to infinity; an input coupler configured to receive an input image beam and provide an output image beam that is injected into the waveguide at a coupling region; and A fifth uniformization layer is disposed between the image projector and the input coupler.

17. An optical system comprising: a waveguide having a front surface and a rear surface that are 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 collimated to infinity; an input coupler configured to receive the collimated image beam and output an input image beam injected into the waveguide at a coupling region; a first aperture expander disposed within the waveguide and configured to receive an input image beam and provide a first plurality of expanded image beams configured to propagate and reflect between the front surface and the rear surface; a leakage image conduit disposed within the waveguide and configured to receive a first portion of the first plurality of expanded image beams and provide a plurality of transmitted image beams, the first portion of the first plurality of expanded image beams being configured to be partially reflected within the leakage image conduit, the leakage image conduit being an elongated member having orthogonal sides and a rectangular cross-section; 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 the plurality of reflected image beams, the second aperture expander configured to provide a second plurality of expanded image beams configured to exit through the rear surface.

18. The optical system according to claim 17, wherein: The leakage image pipe includes an input surface, an output surface, and an inner surface, wherein one of the following exists: The inner surface has a continuous progressive transmission coating in a direction from the input face to the output face; The inner surface has a discrete progressive transmission coating in a direction from the input face to the output face; and The inner surface has a uniform transmissive coating.

19. The optical system according to claim 17, in, The first aperture expander includes a first plurality of partially reflecting facets, the first plurality of partially reflecting facets being tilted at an angle that is one of: An oblique angle relative to at least one of the front surface and a plane perpendicular to the front surface; and perpendicular to the front surface; and wherein the second aperture expander comprises a second plurality of partially reflective facets tilted at an oblique angle relative to at least one of the front surface and a plane perpendicular to the front surface.

20. The optical system of claim 17, wherein: The leaked image pipeline also includes: an outer surface having a reflector disposed perpendicularly to the front surface, the outer surface and the reflector being disposed on a side of the leakage image conduit opposite to the second aperture expander; and An input face configured to receive the first portion of the first plurality of expanded image beams, the input face being perpendicular to the front surface and inclined relative to the exterior surface at an angle ranging between 20° and 160°.

Images