Double helix on single light guide optical element (LOE)

Abstract

An optical device may include a first waveguide to receive and expand a first portion of a guided image beam based on a first image field in a first dimension, and to provide a first plurality of expanded image beams; a second waveguide for receiving and expanding, in the first dimension, one of a second portion of the transmitted guided image beam and a second portion of the guided image beam corresponding to a second image field different from the first image field, and providing a second plurality of expanded image beams, a second waveguide for receiving the first plurality of expanded image beams and providing a transmitted first plurality of expanded image beams; and a third waveguide for receiving and expanding the transmitted first and second plurality of expanded image beams in a second dimension to provide a third plurality of expanded image beams.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on and claims the benefit of priority of U.S. patent application No. 63 / 417,215, entitled “Double-Helix Onto a Single Lightguide Optical Element (LOE)” filed on October 18, 2022, under 35 U.S.C. §119(e), the disclosure of which is incorporated herein by reference in its 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.

[0004] Wearable optical devices such as near-eye displays or smart glasses used in augmented reality applications are often cumbersome to wear and use, thereby limiting their comfort and practicality. Current wearable optical devices may also have a limited field-of-view (FoV), which may be undesirable for the user and may affect safety in some cases. However, total internal reflection (TIR) ​​in the light guide may limit the width of the FoV of the transmitted image. In addition, the low refractive index of the light guide material may further reduce the available angular range to be transmitted. Finally, increasing the field of view may require pushing the limits of geometric boundaries, which may be cumbersome, expensive and may result in a product form factor and / or aesthetic appearance that may be unacceptable in the market. Solutions to these and other problems are needed. Summary of the invention

[0005] According to an example, an optical device is generally described. The optical device may include: a first waveguide configured to receive and expand a first portion of a guided image beam based on a first image field in a first dimension and provide a first plurality of expanded image beams; a second waveguide disposed adjacent to the first waveguide, the second waveguide configured to receive and expand one of a second portion of a transmitted guided image beam corresponding to a second image field that may be different from the first image field and a second portion of the guided image beam in the first dimension and provide a second plurality of expanded image beams, the second waveguide configured to receive the first plurality of expanded image beams and provide the transmitted first plurality of expanded image beams; and a third waveguide disposed adjacent to the second waveguide on a side opposite to the first waveguide, the third waveguide configured to receive and expand the transmitted first plurality of expanded image beams and the second plurality of expanded image beams in a second dimension to provide a third plurality of expanded image beams.

[0006] An optical device according to this example, wherein the first waveguide may further include: a first mirror configured to receive a first portion of the guided image beam and provide a first portion of the reflected guided image beam; and a first aperture expander located in the first region, the first aperture expander may be configured to receive the first portion of the reflected guided image beam and provide a first plurality of expanded image beams, wherein the first waveguide may be configured to receive a second portion of the guided image beam and provide a second portion of the transmitted guided image beam; and wherein the second waveguide may further include: a second mirror configured to receive the second portion of the transmitted guided image beam and provide a second portion of the reflected guided image beam; and a second aperture expander located in a second region that may be laterally displaced from the first region, the second aperture expander configured to receive the second portion of the reflected guided image beam and provide a second plurality of expanded image beams, wherein the second waveguide may be configured to receive the first plurality of expanded image beams and provide the transmitted first plurality of expanded image beams.

[0007] According to the optical device of this example, wherein the first aperture expander may include a first plurality of partially reflecting facets disposed in a first region, the first mirror and the first plurality of partially reflecting facets being parallel to each other and disposed at a first angle relative to the long axis of the first waveguide, and wherein the second aperture expander may also include a second plurality of partially reflecting facets disposed in a second region, the second mirror and the second plurality of partially reflecting facets may be parallel to each other and disposed at a second angle relative to the long axis of the second waveguide, and the second angle may be different from the first angle. According to the optical device of this example, wherein a first portion of the reflected guided image beam may be reflected within the first waveguide by total internal reflection between a first waveguide front surface and a first waveguide rear surface, and wherein a second portion of the reflected guided image beam may be reflected within the second waveguide by total internal reflection between a second waveguide front surface and a second waveguide rear surface.

[0008] According to the optical device of this example, the first waveguide may further include: a first diffraction grating configured to receive a first portion of the guided image beam and provide a first portion of the diffracted guided image beam; a first aperture expander located in the first region, the first aperture expander may be configured to receive the first portion of the diffracted guided image beam and provide a first plurality of expanded image beams, wherein the first waveguide may be configured to receive a second portion of the guided image beam and provide a second portion of the transmitted guided image beam; and wherein the second waveguide may further include: a third diffraction grating configured to receive the second portion of the transmitted guided image beam and provide a second portion of the diffracted guided image beam; a second aperture expander located in a second region that may be laterally displaced from the first region, the second aperture expander may be configured to receive the second portion of the diffracted guided image beam and provide a second plurality of expanded image beams, wherein the second waveguide may be configured to receive the first plurality of expanded image beams and provide the transmitted first plurality of expanded image beams.

[0009] According to the optical device of the example, wherein the first aperture expander may include a second diffraction grating configured to receive a first portion of the diffracted guided image beam and provide a first plurality of expanded image beams, and wherein the second aperture expander may include a fourth diffraction grating configured to receive a second portion of the diffracted guided image beam and provide a second plurality of expanded image beams. According to the optical device of the example, wherein the first portion of the diffracted guided image beam may be reflected within the first waveguide by total internal reflection between a first waveguide front surface and a first waveguide rear surface, and wherein the second portion of the diffracted guided image beam may be reflected within the second waveguide by total internal reflection between a second waveguide front surface and a second waveguide rear surface.

[0010] According to this example, the optical device may also include one of a third stacked waveguide arrangement and a fourth stacked waveguide arrangement, the third stacked waveguide arrangement including: a first waveguide, the first waveguide may also include a first mirror and a first aperture expander, the first mirror is configured to receive a first portion of the guided image beam and provide a first portion of the reflected guided image beam, the first aperture expander may be located in the first region, the first aperture expander may include a first plurality of partially reflective facets disposed in the first region, the first mirror and the first plurality of partially reflective facets may be parallel to each other and may be disposed at a first angle relative to a long axis of the first waveguide, and the first aperture expander may be configured The first waveguide may be configured to receive a first portion of the reflected guided image beam and provide a first plurality of expanded image beams, wherein the first waveguide may be configured to receive a second portion of the guided image beam and provide a second portion of the transmitted guided image beam; and a second waveguide may also include a third diffraction grating and a second aperture expander, the third diffraction grating configured to receive the second portion of the transmitted guided image beam and provide a second portion of the diffracted guided image beam, the second aperture expander may be located in a second region laterally displaced from the first region, the second aperture expander may be configured to receive the second portion of the diffracted guided image beam and provide a second plurality of expanded image beams, wherein the second waveguide may be configured to receive the first plurality of expanded image beams and provide the transmitted first plurality of expanded image beams, the fourth stacked waveguide arrangement may include: a first waveguide, the first waveguide may also include a first diffraction grating and a first aperture expander, the first diffraction grating configured to receive the first portion of the guided image beams and provide the first portion of the diffracted guided image beams, the first aperture expander may be located in the first region, the first aperture expander may include a second diffraction grating disposed in the first region, the first aperture expander may be configured to receive the first portion of the diffracted guided image beams and provide the first plurality of expanded image beams, wherein the first waveguide may configured to receive a second portion of the guided image beam and provide a second portion of the transmitted guided image beam; and a second waveguide, which may also include a second mirror and a second aperture expander, the second mirror being configured to receive the second portion of the transmitted guided image beam and can provide a second portion of the reflected guided image beam, the second aperture expander being located in a second region that may be laterally displaced from the first region, the second aperture expander being configured to receive the second portion of the reflected guided image beam and can provide a second plurality of expanded image beams, wherein the second waveguide may be configured to receive the first plurality of expanded image beams and provide the transmitted first plurality of expanded image beams.

[0011] According to the optical device of this example, one of the first portion of the reflected guided image beam and the first portion of the diffracted guided image beam can be reflected within the first waveguide by total internal reflection between the first waveguide front surface and the first waveguide rear surface, and one of the second portion of the diffracted guided image beam and the second portion of the reflected guided image beam can be reflected within the second waveguide by total internal reflection between the second waveguide front surface and the second waveguide rear surface. According to the optical device of this example, wherein the third waveguide may also include: a third aperture expander, located in the third region and configured to receive the transmitted first and second plurality of expanded image beams, and provide a third plurality of expanded image beams to exit the third waveguide rear surface.

[0012] According to the optical device of this example, wherein the third aperture expander may include a third plurality of partially reflective facets that may be parallel to each other and may be arranged at a third angle that may be tilted relative to the third waveguide front surface, and wherein the transmitted first plurality of expanded image beams and the second plurality of expanded image beams may be reflected by total internal reflection between the third waveguide front surface and the third waveguide rear surface. According to the optical device of this example, wherein the first dimension may be orthogonal to the second dimension.

[0013] According to this example, the optical device may further include: an input coupler configured to receive a collimated image beam from an image projector and provide a first portion of the guided image beam and provide a second portion of the guided image beam, wherein the input coupler may include a reflective inner surface, the input coupler may be configured to receive the first portion of the guided image beam having a first portion of sub-beams and a second portion of the sub-beams, the input coupler may be configured to receive the second portion of the guided image beam having a third portion of the sub-beams and a fourth portion of the sub-beams, the reflective inner surface may be configured to receive the first portion of the sub-beams and provide a reflected first portion of the sub-beams, the reflective inner surface may be configured to receive the third portion of the sub-beams and provide a reflected third portion of the sub-beams, wherein the first waveguide may be configured to receive the reflected first portion of the sub-beams, the reflected first portion of the sub-beams being configured to be transmitted along the first waveguide in a The first waveguide may be configured to receive a second portion of the beamlet, the second portion of the beamlet being configured to propagate in a quadruple helix manner along the first waveguide and to rotate in a second direction that may be opposite to the first direction, the reflected first portion of the beamlet and the second portion of the beamlet may be expanded to provide a first plurality of expanded image beams, wherein the second waveguide may be configured to receive a third portion of the reflected beamlet, the third portion of the reflected beamlet being configured to propagate in a quadruple helix manner along the second waveguide and to rotate in the first direction, the second waveguide may be configured to receive a fourth portion of the beamlet, the fourth portion of the beamlet being configured to propagate in a quadruple helix manner along the second waveguide and to rotate in a second direction that may be opposite to the first direction, the reflected third portion of the beamlet and the fourth portion of the beamlet are expanded to provide a second plurality of expanded image beams.

[0014] According to this example, the optical device may also include: an image projector, arranged adjacent to the input coupler and configured to provide a collimated image beam corresponding to an image field based on the digital image, the collimated image beam including a first portion of the guided image beam corresponding to the first image field, the collimated image beam including a second portion of the guided image beam corresponding to the second image field, wherein the collimated image beam can be collimated to infinity. According to this example, the optical device may further include: a first input coupler configured to receive a first collimated image beam from a first image projector and provide a first portion of the guided image beam; and a second input coupler configured to receive a second collimated image beam from a second image projector and provide a second portion of the guided image beam, wherein the first input coupler may include a first reflective inner surface, the first input coupler may be configured to receive the first portion of the guided image beam having a first portion of a beamlet and a second portion of the beamlet, the reflective inner surface may be configured to receive the first portion of the beamlet and provide the reflected first portion of the beamlet, wherein the first waveguide may be configured to receive the reflected first portion of the beamlet, the reflected first portion of the beamlet being configured to propagate along the first waveguide in a quadruple helix manner and rotate in a first direction, the first waveguide may be configured to receive the second portion of the beamlet, the second portion of the beamlet being configured to propagate along the first waveguide in a quadruple helix manner and rotate in a first direction. The first portion of the reflected beamlet and the second portion of the beamlet can be rotated in a second direction opposite to the first direction, and the reflected beamlet and the second portion can be expanded to provide a first plurality of expanded image beams, wherein the second input coupler can include a second reflective inner surface, the second input coupler can be configured to receive the second portion of the guided image beam having a third portion of the beamlet and a fourth portion of the beamlet, the second reflective inner surface can be configured to receive the third portion of the beamlet and provide the reflected third portion of the beamlet, and wherein the second waveguide can be configured to receive the third portion of the reflected beamlet, the reflected third portion of the beamlet is configured to propagate along the second waveguide in a quadruple helix manner and rotate in the first direction, the second waveguide can be configured to receive the fourth portion of the beamlet, the fourth portion of the beamlet can be configured to propagate along the second waveguide in a quadruple helix manner and rotate in the second direction that can be opposite to the first direction, and the reflected third portion of the beamlet and the fourth portion of the beamlet can be expanded to provide a second plurality of expanded image beams.

[0015] According to this example, the optical device may also include: a first image projector, disposed adjacent to the first input coupler and configured to provide a first collimated image beam corresponding to a first image field based on at least a first portion of the digital image, the first collimated image beam including a first portion of the guided image beam; and a second image projector, disposed adjacent to the second input coupler and configured to provide a second collimated image beam corresponding to a second image field based on at least a second portion of the digital image, wherein the first collimated image beam and the second collimated image beam can be collimated to infinity.

[0016] According to this example, the optical device may also include at least one of the following: a first homogenizer disposed in a plane between the first waveguide top surface and the first waveguide bottom surface; and a second homogenizer disposed in a plane between the second waveguide top surface and the second waveguide bottom surface. According to this example, the optical device may also include at least one of the following: a first retarder wave plate disposed between the first waveguide bottom surface and the second waveguide top surface, the first retarder wave plate may be configured to receive at least one of the first plurality of extended image beams and the second portion of the transmitted guided image beam, and provide a first retarder output, which may be at least one of rotated and depolarized; and a second retarder wave plate, which may be disposed between the second waveguide bottom surface and the third waveguide top surface, the second retarder wave plate may be configured to receive at least one of the second plurality of extended image beams and the transmitted first plurality of extended image beams and may provide a second retarder output, which may be at least one of rotated and depolarized.

[0017] According to the example, the optical device may include at least one of the following: a first dielectric coating disposed on the bottom surface of the input coupler; a second dielectric coating disposed on the bottom surface of the first waveguide; and a third dielectric coating disposed on the bottom surface of the second waveguide. According to the example, the optical device may include at least one of the following: a frame that may be configured to support the first waveguide, the second waveguide, and the third waveguide in positions relative to each other, wherein the first waveguide and the second waveguide may be completely hidden within the frame; a first interface between the input coupler and the first waveguide, the first interface may include a first air gap; a second interface between the first waveguide and the second waveguide, the second interface includes a second air gap; and a third interface between the second waveguide and the third waveguide, the third interface includes a third air gap.

[0018] The foregoing summary is illustrative only and is not intended to be limiting in any way. In addition to the above illustrative aspects, embodiments, and features, other aspects, embodiments, and features will become apparent by reference to the accompanying drawings and the following detailed description. In the accompanying drawings, like reference numerals indicate identical or functionally similar elements. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A block diagram of an optical system according to various examples of the present disclosure is shown.

[0020] Figure 2A Shown are front plan views of optical systems including light guides according to various examples.

[0021] Figure 2B Various examples are shown including Figure 2A Side plan view of the optical system of the light guide.

[0022] Figure 3A Various examples are shown including Figure 2B Side plan view of the optical system of the light guide.

[0023] Figure 3B Various examples are shown including Figure 3A Exploded side plan view of the optical system of the light guide.

[0024] Figure 3C Side plan views of optical systems including alternative light guides according to various examples are shown.

[0025] Figure 3D Side plan views of optical systems including alternative light guides according to various examples are shown.

[0026] Figure 4 Various examples are shown including Figure 3A Side plan view of the optical system of the light guide.

[0027] Figure 5 A front plan view of an image beam applied to an input coupler is shown according to various examples.

[0028] Fig. 6A Shown are front plan views of optical systems including light guides according to various examples.

[0029] Figure 6B Various examples are shown including Fig. 6A Side plan view of the optical system of the light guide.

[0030] Fig. 7A Shown are front plan views of optical systems including light guides according to various examples.

[0031] Figure 7B Various examples are shown including Fig. 7A Side plan view of the optical system of the light guide.

[0032] In the drawings, like reference numerals or characters indicate corresponding parts or similar parts. DETAILED DESCRIPTION

[0033] In the following description, many specific details such as specific structures, components, materials, dimensions, processing steps and techniques are set forth to provide an understanding of the various embodiments of the present application. However, one of ordinary skill in the art will recognize that the various embodiments of the present application can be practiced without these specific details. In other cases, well-known structures or processing steps are not described in detail to avoid obscuring the present application.

[0034] Wearable devices such as near-eye displays and / or smart glasses, which will be described in more detail below, can be implemented by the systems and methods described in accordance with the present disclosure. The system can efficiently provide high-quality optical information to users in a variety of applications.

[0035] Figure 1 A block diagram of an optical system according to various examples of the present disclosure is shown. The optical system 100 may include two or more devices or components. The optical system 100 may be implemented as a hybrid system including various electronic components, optical components, and electro-optical components in general. The optical device 102 may include one or more elements in the optical system 100. The optical system 100, which will be described in more detail below, may include a wearable device 110, such as one or more near-eye displays or smart glasses, which may be worn on or around the user's head to transmit optical information (e.g., a virtual image) to one or more eyes of the user. The present disclosure contemplates both monocular and binocular applications. In various binocular implementations, it should be understood that some aspects of various elements related to power and / or processing may be shared.

[0036] The wearable device 110 may include a controller 112 having a memory 114, wherein the controller 112 may be configured to, for example, send and receive electrical signals to various other elements in the optical system 100, execute program instructions stored in the memory 114 to process and provide information, operate the wearable device 110, and interact with other systems external to the wearable device 110. The controller 112 may include a microcontroller, a processor, various discrete components, a programmable logic device, and / or various interface circuits that may access the memory 114, which may be removable, replaceable, programmable, and reprogrammable to update instructions to the controller 112.

[0037] The wearable device 110 may also include a power management module 116 having a battery 118 (e.g., a battery module), wherein the power management module 116 may be configured to charge, discharge, and monitor power usage of the battery 118. For example, various elements of the wearable device 110 may receive power from the battery 118, including the controller 112, one or more image projectors 120 (e.g., a Projecting Optical Device or POD) having one or more digital images 122, and the optical engine 142 may be configured to drive the one or more image projectors 120 to project the one or more digital images 122.

[0038] The wearable device 110 may also include one or more image projectors 120, each configured to generate a collimated image beam 124 (e.g., image illumination of a collimated image) based on a digital image 122. The collimated image beam may be an illuminated representation of a digital image 122 having an image field 126, which is a two-dimensional representation of a digital image 122 based on a single graphic image (e.g., a static image) or a series of graphic images (e.g., a moving image). The collimated image beam may be collimated to infinity (e.g., an image at infinity). The image field 126 may include a plurality of image subfields 126A to 126F corresponding to respective regions of the collimated image beam 124, wherein each subfield 126A to 126F may correspond to a plurality of different projection angles. For example, the collimated image beam 124 may include an image field 126A corresponding to a first half of the collimated image beam 124 and an image field 126D corresponding to a second half of the collimated image beam 124. The image field 126A may further include a first portion 126B and a second portion 126C. Image field 126D may further include a third portion 126E and a fourth portion 126F.

[0039] The wearable device 110 may also include one or more light guides 130, each light guide including two or more light guide optical elements 132 (e.g., Light-guide Optical Element, LOE) that can be represented as waveguides (e.g., Waveguide, WG). As used herein, the terms or phrases light guide, light guide optical element, and waveguide are related and can be considered synonymous in some aspects. Each light guide optical element 132 may include one or more transparent material components configured to receive and propagate light, wherein the light can enter various outer and inner surfaces of one or more transparent material components, and leave from various outer and inner surfaces. For example, the light guide optical element 132 may include optical glass or other suitable materials, which are transformed into various complex optical structures using processes that may include coating, stacking, cutting, polishing, and forming transparent materials. For example, the process may also include adding a partially reflective material or a fully reflective material, such as a mirror coating and one or more homogenizing elements, on or within the surface of one or more of the light guide optical elements 132. For example, the light guide 130 may also include one or more passive optical elements 134, such as one or more input couplers or one or more retarder wave plates.

[0040] The wearable device 110 may also include one or more optical engines 142 coupled to the one or more image projectors 120 and the one or more light guides 130. The optical engine 142 may be configured to directly operate the image projector 120 under the direction of the controller 112. For example, the optical engine 142 may provide graphics processing of the digital image before projecting an illuminated representation of the one or more digital images 122 by the image projector 120.

[0041] The wearable device 110 may also include a frame 148 (e.g., a structure) for supporting and maintaining two or more light-guiding optical elements 132 (e.g., a first waveguide, a second waveguide, and a third waveguide) in positions relative to each other in the wearable device 110. For example, the frame 148 may support and maintain the first image projector 120 in a position next to the first light-guiding optical element 132. Similarly, the frame 148 may support and maintain the second image projector 120 in a position next to the second light-guiding optical element 132. In this way, the frame 148 may support and maintain one or two image projectors 120 and light guides 130 pairs worn on or around the user's head configured to provide a virtual image to one or both eyes of the user. References are made herein 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 148 or referenced to a three-dimensional (3D) reference (e.g., X, Y, Z axis).

[0042] 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 112 and stored in the memory 114. The host computer 170 may communicate with one or more elements of the wearable device 110 via a bus 188 to send and / or receive power, status, control, and image information. In this manner, the host computer 170 may provide power to charge the battery 118, provide instructions to the controller 112 and various other elements of the wearable device 110 and receive status from the controller 112 and various other elements of the wearable device 110, and provide data based on the digital image 122 to the optical engine 142.

[0043] Figure 2A Shown are front plan views of optical systems including light guides according to various examples. Figure 2B Various examples are shown including Figure 2A. As will be described more fully below, in various examples, the present disclosure describes pairs of cascaded or dual-stacked rectangular waveguides, wherein each waveguide receives a portion (e.g., approximately half) of an input image field, and wherein two sub-portions of each portion of the input image field can travel and be reflected within each waveguide by quadruple internal reflection while rotating in opposite directions (e.g., in a spiral manner) within the waveguide, and wherein both of the reflected and rotated portions of the input image field can then be coupled into a third waveguide and projected (e.g., outcoupled) as a virtual image to an eye of a user. For example, optionally cascading two rectangular lightguides with a low refractive index material can achieve transmission of a wider field of view (FoV), wherein each individual rectangular lightguide transmits only a portion of a final image, and portions of the final image are coupled into a third lightguide optical element. Figures 1 to 2B 1 shows an optical system 100 that can include an optical device 202 having one or more optical elements of the optical system 100. The optical device 202 can be similar in some aspects to Figure 1 The optical device 102 shown is similar. The optical device 202 may include a light guide 130 having two or more light guide optical elements 132.

[0044] According to an example, optical device 202 may include input coupler 220 (e.g., a wedge-shaped coupling prism) configured to receive collimated image beam 206 from image projector 120 and configured to provide both first portion 208 of the directed image beam and second portion 214 of the directed image beam. As shown, first portion 208 of the directed image beam and second portion 214 of the directed image beam may be separated by first dividing plane 226 (e.g., corresponding to the YZ plane, but at Figure 2AThe optical device 202 may include a first waveguide 230 that may have a first mirror 232 configured to receive the first portion 208 of the guided image beam and provide a first portion 234 of the reflected guided image beam. The first waveguide 230 may have a first aperture expander 240 located in a first region 242. The first aperture expander 240 may include a plurality of partially reflective facets 246 that may be parallel to each other and to the first mirror 232 and may be tilted at a first angle 239 relative to an X-axis 294 (e.g., a horizontal axis of the first waveguide 230). The partially reflective facets may be implemented as partially reflective mirror surfaces. The first angle 239 may be in a range from about 20° to 60° and may correspond to a dynamic range that may depend on the reflective architecture of the facets. For example, U.S. Patent Publication 20190064518, entitled “Aperture Multiplier Using aRectangular Waveguide” and assigned to the applicant, describes various details related to image rays propagating relative to partially reflective internal facets in a waveguide. As used herein, the terms aperture expander, aperture expansion, and aperture multiplication for producing an expanded image beam may be considered equivalent to one another. The mutually parallel first mirror 232 and the first plurality of partially reflective facets 246 may cause a large mechanical offset tolerance during the manufacturing process. Each of the partially reflective facets 246 may have a constant reflectivity. Alternatively, the reflectivity of the partially reflective facets 246 may increase or decrease in a direction away from the first mirror 232 depending on the application. The first aperture expander 240 may be configured to receive a first portion 234 of the reflected guided image beam and provide a first plurality of expanded image beams 248. The first waveguide 230 may be configured to receive a second portion 214 of the guided image beam and provide a second portion 244 of the transmitted guided image beam. First portion 208 of directed image beam and second portion 214 of directed image beam may each correspond to approximately half of image beam 206 projected from image projector 120, although other ratios may be used. Figure 2A A gap is shown between image projector 120 and input coupler 220, but for this and other examples, such a gap is for illustration purposes and may not exist in actual implementations. Thus, the half image provided by first portion 208 of the guided image beam may fill the available angular range within first waveguide 230.

[0045] The optical device 202 may include a second waveguide 250 having a second mirror 252 configured to receive the second portion 244 of the transmitted guided image beam and provide a second portion 254 of the reflected guided image beam. As described, the first mirror 232 and the second mirror 252 may be fully reflective mirrors or partially reflective mirrors. For example, the first mirror 232 may have a different reflectivity compared to the second mirror 252 to compensate for the loss of light energy from the first waveguide 230 to the second waveguide 250. In addition, the first mirror 232 may be partially reflective in the case where some portions of the first mirror 232, for example, laterally overlap (e.g., partially obstruct) the second mirror 252. The second waveguide 250 may have a second aperture expander 260 located in a second region 262 that is laterally displaced 264 from the first region 242.

[0046] The second aperture expander 260 may include a second plurality of partially reflecting facets 266 disposed in the second region 262, wherein the second plurality of partially reflecting facets 266 and the second mirror 252 may be parallel to each other and disposed at a second angle 259 that may be different from the first angle 239. As described above, the parallel second mirror 252 and the second plurality of partially reflecting facets 266 may cause a larger mechanical offset tolerance during the manufacturing process. Similar to the first angle 239, the second angle 259 may also be in a range from about 20° to 60° and may correspond to a dynamic range that may depend on the reflective architecture of the facets. However, there may be a difference between the first angle 239 and the second angle 259, wherein beams propagating along the corresponding waveguides may propagate at the same angle even though the beams may originate from different angles when injected from the image projector 120. For example, for a large field in a glassy medium having a dynamic range of about 40 degrees (e.g., about 60 degrees in air), the difference between the respective centers of two different field portions (e.g., first portion 208 of the directed image beam and second portion 214 of the directed image beam) may have a dynamic range of approximately half, or about 20 degrees. In this example using a mirror reflector, the difference between the mirror angles of first angle 239 and second angle 259 may be about 10 degrees.

[0047] For example, a first technical benefit of having the first angle 239 be different from the second angle 259 may include improved light homogenization and virtual image reproduction by avoiding image stitching. A second technical benefit of having the first angle 239 be different from the second angle 259 may include intensity compensation, wherein the second angle 259 provides a greater energy reflection capability after moving through a greater distance between the second mirror 252 and the second aperture expander 260 than between the first mirror 232 and the first aperture expander 240. The second aperture expander 260 may be configured to receive the reflected second portion 254 of the guided image beam and provide a second plurality of expanded image beams 268. The second waveguide 250 may be configured to receive the first plurality of expanded image beams 248 and provide a transmitted first plurality of expanded image beams 278. Thus, the half image provided by the second portion 214 of the guided image beam may fill the available angular range within the second waveguide 250. Reflection from the input coupler 220 and transmission through the input coupler 220 may achieve total internal reflection (TIR) ​​from the first waveguide front surface 231 and the first waveguide rear surface 233. Reflection from the first mirror 232 may achieve total internal reflection from the first waveguide top surface 235 and the first waveguide bottom surface 237. Reflection from the second mirror 252 may achieve total internal reflection from the second waveguide top surface 255 and the second waveguide bottom surface 257.

[0048] The first aperture expander 240 and the second aperture expander 260 may overlap laterally (e.g., horizontally as shown) by an overlap distance 290, which may be in a range, for example, between 1% and 20% of the length of the first waveguide 230 and the second waveguide 250, which are preferably equal in length. The overlap distance 290 may preferably be in a range between 5% and 10% of the length of the first waveguide 230. For example, the technical benefit of the overlap of the first aperture expander 240 and the second aperture expander 260 may contribute to the continuity of the combined image. Alternatively, the first aperture expander 240 and the second aperture expander 260 may not overlap, so the overlap distance 290 may be zero, where image continuity is not an issue. As an alternative, the order of the first waveguide 230 and the second waveguide 250 (e.g., the sequence of light treatments) may be reversed. Furthermore, for example, another rectangular waveguide similar to both the first waveguide 230 and the second waveguide 250 may also be used and may include another aperture expander that spans some or all of the lateral areas of the first aperture expander 240 and the second aperture expander 260. In yet another alternative, a separate, possibly smaller, image projector 120 may be used for each rectangular waveguide with or without a separate coupling-in prism 220. When used without a separate coupling-in prism, each separate projector 120 may be oriented at an appropriate angle relative to the respective waveguide to inject the input image beam 206 (or a portion of the input image beam 206) to cause quadruple internal reflection along the respective waveguide, as described above.

[0049] The optical device 202 can include a third waveguide 270 (e.g., a "slab") having a third aperture expander 272 located in a third region 274 (e.g., vertically oriented) and configured to receive the transmitted first plurality of expanded image beams 278 (e.g., direct the transmitted first plurality of expanded image beams 278) and the second plurality of expanded image beams 268, and provide a third plurality of expanded image beams 280 to exit the third waveguide rear surface 273 toward an eyebox 282 (e.g., an outcoupling region) and an eye 284 of a user or wearer of the wearable device 110. For example, the directed transmitted beams can be distinguished from free space transmitted beams that can be transmitted between optical components. The third aperture expander 272 can include a third plurality of partially reflective facets 276 that can be parallel to each other and can be tilted at a third angle 279 relative to the Y-axis 296 (e.g., the vertical axis of the third waveguide 270) and tilted to the third waveguide front surface 271. For completeness, the Z-axis 298 corresponds to the direction perpendicular to the XY plane.

[0050] Transverse (or vertical) aperture expansion can also be expressed as aperture multiplication. Therefore, the first waveguide 230, the second waveguide 250 and the third waveguide 270 together provide a two-dimensional (2-D) expansion of the input image beam 206 from the image projector 120. In this way, the first waveguide 230, the second waveguide 250 and the third waveguide 270 can be configured to receive and continuously reflect the guided image beam to provide an expanded image beam. The third plurality of partially reflecting facets 276 can be perpendicular to the YZ plane. Alternatively, for example, the third plurality of partially reflecting facets 276 can be inclined obliquely relative to both the YZ plane and a set of elongated parallel external faces of the third waveguide 270 (e.g., the third waveguide front surface 271 and the third waveguide rear surface 273). For example, the above-mentioned US Patent Publication US20190064518 also describes how a single polarization (e.g., preferably s-polarization) with an orientation orthogonal to the waveguide surface can be used to illuminate the waveguide.

[0051] For various examples disclosed herein, the first waveguide 230 may include a first waveguide front surface 231 and a first waveguide rear surface 233 that are parallel to each other. The first waveguide 230 may also include a first waveguide top surface 235 and a first waveguide bottom surface 237 that are parallel to each other. Similarly, for various examples disclosed herein, the second waveguide 250 may include a second waveguide front surface 251 and a second waveguide rear surface 253 that are parallel to each other. The second waveguide 250 may also include a second waveguide top surface 255 and a second waveguide bottom surface 257 that are parallel to each other. In this manner, the mutually parallel opposing sides and mutually parallel opposing top and bottom surfaces of each of the first waveguide 230 and the second waveguide 250 may together describe a rectangular waveguide.

[0052] For example, the first waveguide 230 partially reflecting facets 246 can be perpendicular to the first waveguide front surface 231, while the second waveguide 250 partially reflecting facets 266 can be perpendicular to the second waveguide front surface 251. Alternatively, for example, the first plurality of partially reflecting facets 246 can be obliquely inclined relative to two sets of elongated parallel exterior surfaces of the first waveguide 230 (e.g., the first waveguide front surface 231 and the first waveguide rear surface 233 and / or the first waveguide top surface 235 and the first waveguide bottom surface 237). Similarly, for example, the second plurality of partially reflecting facets 266 can be obliquely inclined relative to two sets of elongated parallel exterior surfaces of the second waveguide 250 (e.g., the second waveguide front surface 251 and the second waveguide rear surface 253 and / or the second waveguide top surface 255 and the second waveguide bottom surface 257). The first waveguide bottom surface 237 can be disposed adjacent to the second waveguide top surface 255.

[0053] The third waveguide 270 may include a third waveguide front surface 271 and a third waveguide rear surface 273 that are parallel to each other. The third waveguide 270 may also include a third waveguide top surface 275 disposed adjacent to the second waveguide bottom surface 257. The bottom profile 277 of the third waveguide 270 may have the form of an isosceles trapezoid, but may also be smoothly curved, square, etc. Therefore, the side (e.g., Figure 2A The left and right sides shown in the figure) and the bottom surface. Figure 2B As shown, the light guide 130 may include a first interface 213 disposed between the input coupler 220 and the first waveguide 230, a second interface 215 disposed between the first waveguide 230 and the second waveguide 250, and a third interface 217 disposed between the second waveguide 250 and the third waveguide 270. Each of the first interface 213, the second interface 215, and the third interface 217 may include a separate air gap, a coating, or a passive optical element 134 such as a polarizer disposed in the interface, wherein these interface media may maintain the total internal reflection (TIR) ​​of the quadruple propagation in their associated rectangular waveguides. FIG. 2A to FIG. 2B As shown in , the first waveguide 230 may include a reflective element and the second waveguide 250 may include a reflective element. Thus, the optical device 202 and the light guide 130 may include a first stacked waveguide arrangement of a reflective type.

[0054] Figure 3A Various examples are shown including Figure 2B Side plan view of the waveguide optical system. Figure 3B Various examples are shown including Figure 3A Exploded side plan view of the waveguide optical system. Figure 3C Side plan views of optical systems including alternative waveguides according to various examples are shown. Figure 3DA side plan view of an optical system including alternative waveguides according to various examples is shown. According to an example, the thickness 330 of the first waveguide 230, the second waveguide 250, and the third waveguide 270 can be substantially equal. However, the relative height of the first waveguide 230 compared to the height of the second waveguide 250 can vary. In addition, the first waveguide front surface 231, the second waveguide front surface 251, and the third waveguide front surface 271 can be coplanar with each other. Therefore, in the case of equal thickness and coplanar front surfaces, it should be understood that the first waveguide rear surface 233, the second waveguide rear surface 253, and the third waveguide rear surface 273 can also be coplanar with each other. For example, the technical benefits of the equal thickness and coplanarity of the first waveguide 230, the second waveguide 250, and the third waveguide 270 can include minimizing power losses in the transmission of light between adjacent waveguides. As described, each of the first waveguide 230, the second waveguide 250, and the third waveguide 270 has parallel front and rear surfaces such that light propagating and reflected within each of the waveguides can be reflected by total internal reflection (TIR) ​​between the corresponding front and rear surfaces within each of the waveguides.

[0055] For example, the first guided image beam 234 can be reflected within the first waveguide 230 by total internal reflection between the first waveguide front surface 231 and the first waveguide rear surface 233, and the reflected light can exit the first waveguide 230 at the first waveguide bottom surface 237. Since the first plurality of partially reflecting facets 246 are parallel to the first mirror 232, the beam can be coupled out of the first waveguide 230, for example, at the same angle at which it was coupled in from the input coupler 220. Similarly, for example, the second portion 254 of the reflected guided image beam can be reflected within the second waveguide 250 by total internal reflection between the second waveguide front surface 251 and the second waveguide rear surface 253, and the reflected light can exit the second waveguide 250 at the second waveguide bottom surface 257. Finally, the transmitted first plurality of expanded image beams 248 and the second plurality of expanded image beams 268 can be reflected by total internal reflection between the third waveguide front surface 271 and the third waveguide rear surface 273, and the reflected light can exit the third waveguide rear surface 273 after reflecting from the third aperture expander 272.

[0056] In one example, Figure 3AThe light guide 130 is shown to include a first interface 213 disposed between the input coupler 220 and the first waveguide 230, a second interface 215 disposed between the first waveguide 230 and the second waveguide 250, and a third interface 217 disposed between the second waveguide 250 and the third waveguide 270. Each of the first interface 213, the second interface 215, and the third interface 217 may include a separate air gap, a coating, or a passive optical element 134 such as a polarizer disposed in the interface. Total internal reflection (TIR) ​​guidance within the first waveguide 230 and the second waveguide 250 may be improved by the application of various optical coatings, the presence of air gaps, and / or the use of low refractive index materials above or below the first waveguide 230 and / or the second waveguide 250.

[0057] Figure 3B Various examples are shown including Figure 3A 1. A side plan exploded view of an optical system of a lightguide of FIG. 1. The input coupler bottom surface 227 may include a first coating 302, the first waveguide top surface 235 may include a second coating 306, the first waveguide bottom surface 237 may include a third coating 310, the second waveguide top surface 255 may include a fourth coating 314, the second waveguide bottom surface 257 may include a fifth coating 318, and the third waveguide top surface 275 may include a sixth coating 322. Each of the coatings may be uniform across the surface of the relevant portion and may include at least one of a dielectric coating that may have polarization dependence, a dielectric reflective coating, a variable reflective coating, or a partially transmissive mirror coating.

[0058] Figure 3C A side plan view of an optical system including an alternative light guide according to various examples is shown. The retarder wave plate is a passive optical element 134 that may include a birefringent material, a crystalline material, or a polymer material that may be used to produce a phase shift between polarization components in a light beam. The retarder wave plate may be used to at least one of rotate and depolarize a light beam passing through the retarder wave plate without attenuating, deflecting, or shifting the light beam. Figure 3CAs shown, the first retarder wave plate 304 can be disposed at the first interface 213 in the middle of at least a portion of the area between the input coupler bottom surface 227 and the first waveguide top surface 235, and is configured to at least one of rotate and depolarize at least some portion of the light transferred from the input coupler 220 to the first waveguide 230. The second retarder wave plate 312 can be disposed at the second interface 215 in the middle of at least a portion of the area between the first waveguide bottom surface 237 and the second waveguide top surface 255, and is configured to at least one of rotate and depolarize at least some portion of the light transferred from the first waveguide 230 to the second waveguide 250. Finally, the third retarder wave plate 320 can be disposed at the third interface 217 in the middle of at least a portion of the area between the second waveguide bottom surface 257 and the third waveguide top surface 275, and is configured to at least one of rotate and depolarize at least some portion of the light transferred from the second waveguide 250 to the third waveguide 270. In some applications, the second retarder wave plate 312 can be used to redirect light reflected from the first plurality of partially reflective facets 246, and / or the third retarder wave plate 320 can be used to redirect light reflected from one / both of the first plurality of partially reflective facets 246 and the second plurality of partially reflective facets 266 to accommodate the polarization desired by the third plurality of partially reflective facets 276.

[0059] Figure 4 Various examples are shown including Figure 3A A side plan view of the waveguide optical system. Figures 2A to 4 , the input coupler 220 can have a reflective inner surface 408 (e.g., a reflective internal face) and be configured to receive the first portion 208 of the guided image beam having the first portion 210 of the beamlets and the second portion 212 of the beamlets. The input coupler 220 can also be configured to receive the second portion 214 of the guided image beam having the third portion 216 of the beamlets and the fourth portion 218 of the beamlets. FIG. 3A to FIG. 3C as well as Figure 4 As shown, the reflective inner surface 408 can be disposed on the rear surface 223 of the input coupler 220 and can be configured to receive the first portion 210 of the beamlet and provide a reflected first portion 410 of the beamlet. Figure 3D As shown, for example, the reflective interior surface 408 can be disposed on the front surface 221 of the input coupler 220 when the input coupler 220 is rotated 180 degrees so that the image projector 120 can be mounted in a symmetrically opposite orientation.

[0060] The reflective inner surface 408 can be configured to receive the third portion 216 of the beamlet and provide the reflected third portion 416 of the beamlet. In addition, the second portion 212 of the beamlet and the fourth portion 218 of the beamlet can be configured to pass through the input coupler 220 without reflecting from the reflective inner surface 408. In this manner, the reflected first portion 410 of the beamlet and the unreflected second portion 412 of the beamlet can exit the input coupler bottom surface 227 at different predetermined angles and enter the first waveguide top surface 235 at substantially the same exit angles because the input coupler bottom surface 227 is substantially parallel to the first waveguide top surface 235. As shown in FIG. Figure 2A As described, the first portion 208 of the directed image beam and the second portion 214 of the directed image beam can be divided into two halves by the first dividing plane 226, as shown, the first dividing plane 226 divides the input coupler 220 equally in a left-right manner. Figure 4 The first portion 210 of the beamlets and the second portion 212 of the beamlets may also be separated by a second dividing plane 426 (eg, corresponding to a plane including the X-axis 294, but in Figure 4 The second dividing plane 426 divides the first portion 208 of the guided image beam into an upper half 404 (eg, the rear half) of the first portion 210 having the sub-beams and a lower half 406 (eg, the front half) having the sub-beams 212.

[0061] A first portion 410 of the reflected sub-beam may enter the first waveguide top surface 235 and be reflected from the first mirror 232 tilted at a first angle 239 relative to the X-axis 294 (e.g., the horizontal axis of the first waveguide 230) to become a first portion 236 of the reflected sub-beam rotated in the first direction 432, and a second portion 412 of the sub-beam may enter the first waveguide top surface 235 and be reflected from the first mirror 232 to become a second portion 238 of the reflected sub-beam rotated in a second direction 434 that may be opposite to the first direction 432. In this manner, since the image beam 206 from the image projector 120 is coupled by the input coupler 220 tilted at the coupling angle 229, and then the first half of the coupled image is reflected at the first angle 239, and the second half of the coupled image is reflected at the second angle 259, the initial propagation direction at the coupling angle that may be tilted to the opposite pair of parallel faces of the first waveguide 230 may cause the coupled-in image to advance along the first waveguide 230 through quadruple internal reflection. Thus, the first portion 236 of the reflected sub-beam and the second portion 238 of the reflected sub-beam can propagate in substantially opposite directions within the first waveguide 230 while moving through the length of the first waveguide 230 in a direction away from the first mirror 232 in a manner that can be described as a quadruple, helical (e.g., a helix), or similar spiral.

[0062] For example, the above-mentioned US patent publication US20190064518 also describes various details related to quadruple internal reflections in an elongated waveguide. In this way, an image from an image projector can be coupled into an optical waveguide in an initial propagation direction at a coupling angle that is inclined to the relative pair of parallel planes, so that the image advances along the waveguide through quadruple internal reflections. In the example currently described, the propagated image beam can then be coupled into an adjacent waveguide. The first aperture expander 240 may include a first plurality of partially reflective facets 246 disposed in a first region 242. When a first portion 236 of the reflected sub-beam and a second portion 238 of the reflected sub-beam propagate in a direction away from the first mirror 232 in a quadruple, spiral manner, the first portion 236 of the reflected sub-beam and the second portion 238 of the reflected sub-beam can enter the first region 242 and be reflected by the first aperture expander 240 to provide a first plurality of expanded image beams 248 configured to exit from the first waveguide bottom surface 237. Thus, the first portion 236 of the reflected beamlet and the second portion 238 of the reflected beamlet may be extended in a first dimension (eg, in the direction of the X-axis 294 ).

[0063] The reflected third portion 416 of the sub-beam and the unreflected fourth portion 418 of the sub-beam can exit the input coupler bottom surface 227 at different predetermined angles and enter the first waveguide top surface 235 at substantially the same exit angles because the input coupler bottom surface 227 is substantially parallel to the first waveguide top surface 235. As mentioned above, the first waveguide 230 can be configured to receive the second portion 214 of the guided image beam including the reflected third portion 416 of the sub-beam and the fourth portion 418 of the sub-beam, and provide a transmitted second portion 244 of the guided image beam, which passes through the first waveguide 230 from the first waveguide top surface 235 to the first waveguide bottom surface 237 while being reflected by total internal reflection between the first waveguide front surface 231 and the first waveguide rear surface 233, and can exit from the first waveguide bottom surface 237 at different predetermined angles and enter the second waveguide top surface 255 at substantially the same exit angle, because the first waveguide bottom surface 237 is substantially parallel to the second waveguide top surface 255.

[0064] The transmitted second portion 244 of the guided image beam may pass through the first waveguide 230 in an area adjacent to the first mirror 232, wherein some portions of the transmitted second portion 244 of the guided image beam (e.g., derived from the second portion 214 of the guided image beam) may overlap in the area 292 and be reflected by the first mirror 232 to resolve the image overlap. Alternatively, the non-transmitted second portion 244 of the guided image beam may overlap or be reflected by the first mirror 232, such that the first mirror 232 reflects only the first portion 208 of the guided image beam and not any of the image beams in the second portion 214 of the guided image beam, wherein image overlap may not be an issue.

[0065] The second portion 244 of the transmitted guided image beam (derived from the reflected third portion 416 of the beamlet and the unreflected fourth portion 218 of the beamlet) can enter the second waveguide top surface 255 and reflect from the second mirror 252, which is tilted at a second angle 259 relative to the X-axis 294 (e.g., the long axis of the second waveguide 250), to become the reflected third portion 256 of the beamlet that is rotated in the first direction 452, and the fourth portion 218 of the beamlet can enter the second waveguide top surface 255 and reflect from the first mirror 232 to become the reflected fourth portion 258 of the beamlet that is rotated in the second direction 454 that can be opposite to the first direction 452. Thus, the reflected third portion 256 of the beamlet and the reflected fourth portion 258 of the beamlet can propagate in substantially opposite directions within the second waveguide 250 while moving in a direction away from the second mirror 252 over the length of the second waveguide 250 in a four-fold, spiral fashion.

[0066] As the reflected third portion 256 of the beamlet and the reflected fourth portion 258 of the beamlet propagate in a direction away from the second mirror 252 in a fourfold, spiral manner, the reflected third portion 256 of the beamlet and the reflected second portion 258 of the beamlet may enter the second region 262 and be reflected by the second aperture expander 260 to provide a second plurality of expanded image beams 268 configured to exit from the second waveguide bottom surface 257. As the reflected third portion 256 of the beamlet and the reflected fourth portion 258 of the beamlet propagate in a direction away from the second mirror 252 in a fourfold, spiral manner, the reflected third portion 256 of the beamlet and the reflected fourth portion 258 of the beamlet may enter the second region 262 and be reflected by the second aperture expander 260 to provide a second plurality of expanded image beams 268 configured to exit from the second waveguide bottom surface 257. Thus, the third portion 256 of the reflected beamlet and the fourth portion 258 of the reflected beamlet may be extended in the first dimension (eg, the direction of the X-axis 294 ).

[0067] The first waveguide 230 may include a first homogenizer 286 disposed in parallel planes disposed vertically approximately midway between the first waveguide top surface 235 and the first waveguide bottom surface 237, and horizontally (e.g., laterally) between the first mirror 232 and the first partially reflecting facet 246 of the first aperture expander 240. Similarly, the second waveguide 250 may include a second homogenizer 288 disposed in parallel planes disposed vertically approximately midway between the second waveguide top surface 255 and the second waveguide bottom surface 257, and horizontally (e.g., laterally) between the second mirror 252 and the second partially reflecting facet 266 of the second aperture expander 260. Various light homogenizers may be used alone or in combination with one another to provide improved illumination uniformity as well as other benefits. The homogenizer (286, 288) may include a partially planar reflector, partially transmissive surface, or film added to the corresponding waveguide (230, 250) as a semi-reflective surface. When there is a transmissive homogenizer disposed within the waveguide, the transmissive homogenizer can effectively double the number of reflected beams by reflecting an incident beam moving through the waveguide in an ascending or descending manner. By ascending, some portion of the light from below the homogenizer can be reflected from the lower surface of the homogenizer, and the remaining portion of the ascending beam can pass through the homogenizer, thereby effectively doubling the number of beams. By descending, some portion of the light from above the homogenizer can be reflected from the upper surface of the homogenizer, and the remaining portion of the descending beam can pass through the homogenizer, thereby effectively doubling the number of beams.

[0068] According to an example, the optical system 100 may include a frame 148 (e.g., a structural element) configured to support the wearable device 110, the controller 112, the memory 114, the power management module 116, the battery 118, the image projector 120, the light guide 130 including two or more light guide optical elements 132 (e.g., the first waveguide 230, the second waveguide 250, the third waveguide 270), the optical engine 142, two or more of the first waveguide 230, the second waveguide 250, and the third waveguide 270 in a position relative to each other. In an example, the frame 148 may support the input coupler 220 and the first waveguide 230 so that the first interface 213 between the input coupler 220 and the first waveguide 230 includes a first air gap. In an example, the frame 148 may support the first waveguide 230 and the second waveguide 250 so that the second interface 215 between the first waveguide 230 and the second waveguide 250 includes a second air gap. In an example, the frame 148 may support the second waveguide 250 and the third waveguide 270 such that the third interface 217 between the second waveguide 250 and the third waveguide 270 includes a third air gap. In an example, the frame 148 may support the first waveguide 230 and the second waveguide 250 such that, for example, the first waveguide 230 and the second waveguide 250 may be completely hidden within the frame 148.

[0069] Figure 5 A front plan view of an image beam applied to an input coupler according to various examples is shown. Figure 4 and Figure 5, the input face 225 of the input coupler 220 may be divided into four quadrants by the first dividing plane 226 and the second dividing plane 426. As shown, the image beam 206 from the image projector 120 may be directed to the input face 225 of the input coupler 220 at the intersection of the first dividing plane 226 and the second dividing plane 426. The first portion 208 of the guided image beam corresponding to the first portion 210 of the beamlet may be at least partially directed to the reflective internal face of the input coupler rear surface 223 to be reflected back into the input coupler 220 as the reflected first portion 410 of the beamlet and to enter the first waveguide 230 at the first mirror 232 as the reflected first portion 236 of the beamlet at a predetermined angle that depends on the origin of the image pixel image field corresponding to the image beam at the first quadrant Q1. A first portion 208 of the directed image beam corresponding to the second portion 212 of the beamlet can be directed through the input coupler bottom surface 227 and enter the first waveguide 230 at the first mirror 232 as a reflected second portion 238 of the beamlet at another predetermined angle that depends on the origin of the image pixel image field corresponding to the image beam at the second quadrant Q2. Similarly, a second portion 214 of the directed image beam corresponding to the third portion 216 of the beamlet can be at least partially directed to the reflective interior facet of the input coupler back surface 223 to be reflected back into the input coupler 220 as a reflected third portion 416 of the beamlet and enter the first waveguide 230 adjacent to the first mirror 232 as a transmitted first portion of the second portion 244 of the directed image beam at a predetermined angle that depends on the origin of the image pixel image field corresponding to the image beam at the third quadrant Q3. A second portion 214 of the guided image beam corresponding to the second portion 218 of the sub-beam can be guided through the input coupler bottom surface 227 and enter the first waveguide 230 adjacent to the first mirror 232 as a second portion of the transmitted second portion 244 of the guided image beam at another predetermined angle that depends on the origin of the image pixel image field corresponding to the image beam at the fourth quadrant Q4.

[0070] According to an example, the optical system 100 may include an image projector 120 configured to generate a collimated image beam 206 based on a digital image 122, wherein the collimated image beam may be collimated to infinity. The optical system 100 may include an input coupler 220 configured to receive the collimated image beam 206 from the image projector 120 and to provide a first portion 208 of the directed image beam and a second portion 214 of the directed image beam. As described more fully below, the first portion 208 of the directed image beam may include a first portion 210 of the beamlet and a second portion 212 of the beamlet. Additionally, the second portion 214 of the directed image beam may include a third portion 216 of the beamlet and a fourth portion 218 of the beamlet.

[0071] The optical system 100 may include a first waveguide 230 having a first mirror 232, which may be configured to receive the first portion 208 of the guided image beam and provide a first portion 234 of the reflected guided image beam. The first waveguide may have a first aperture expander 240 located in a first region 242. For example, the first aperture expander 240 may be configured to receive the first portion 234 of the reflected guided image beam and provide a first plurality of expanded image beams 248, wherein the first portion 234 of the reflected guided image beam may be expanded laterally along the X-axis 294 to provide a first plurality of expanded image beams 248 that may exit from a first waveguide bottom surface 237. The first waveguide 230 may be configured to receive the second portion 214 of the guided image beam and provide a second portion 244 of the transmitted guided image beam.

[0072] The optical system 100 may include a second waveguide 250 having a second mirror 252 that may be configured to receive the second portion 244 of the transmitted guided image beam and provide the second portion 254 of the reflected guided image beam. The second waveguide 250 may have a second aperture expander 260 located in a second region 262 that may be laterally displaced 264 from the first region 242. For example, the second aperture expander 260 may be configured to receive the second portion 254 of the reflected guided image beam and provide a second plurality of expanded image beams 268, wherein the second portion 254 of the reflected guided image beam may be laterally expanded along the X-axis 294 to provide a second plurality of expanded image beams 268 that may exit from a second waveguide bottom surface 257. The second waveguide 250 may be configured to receive the first plurality of expanded image beams 248 and provide a transmitted first plurality of expanded image beams 278 to exit from the second waveguide bottom surface 257.

[0073] The optical system 100 can include a third waveguide 270 that can have a third aperture expander 272 (e.g., oriented vertically) located in a third region 274, the third aperture expander 272 configured to receive the transmitted first plurality of expanded image beams 278 and the second plurality of expanded image beams 268, and provide a third plurality of expanded image beams 280 to exit the third waveguide back surface 273 toward an eye box 282 and an eye 284 of a user or wearer of the wearable device 110. For example, the third aperture expander 272 can include a plurality of partially reflective facets 276 that can be parallel to each other and can be tilted at a third angle 279 relative to a Y-axis 296 (e.g., a vertical axis of the third waveguide 270) and tilted to the third waveguide front surface 271, wherein the transmitted first plurality of expanded image beams 248 and the second plurality of expanded image beams 268 can be vertically expanded along the Y-axis 296. In some examples, the light guide 130 may include passive and active optical components as various light guide optical elements 132 (LOEs), including an input coupler 220 , a first waveguide 230 , a second waveguide 250 , and a third waveguide 270 .

[0074] Fig. 6A Shown are front plan views of optical systems including light guides according to various examples. Figure 6B Various examples are shown including Fig. 6A Side plan view of the optical system of the light guide.

[0075] FIG. 6A to FIG. 6B The image bundle propagation in can be similar to that in reference Figures 1 to 5 Beam propagation is described herein, wherein corresponding reference numerals may indicate corresponding functions.

[0076] According to an example, the optical device 602 may include an input coupler 220 configured to receive the collimated image beam 206 from the image projector 120 and provide a first portion 208 of the directed image beam and a second portion 214 of the directed image beam. The optical device 602 may be similar in some respects to Figure 1 The optical device 102 and FIG. 2A to FIG. 2B The optical device 202 is shown. Figures 2A to 4 , the input coupler 220 can have a reflective inner surface 408 (e.g., a reflective internal face) and be configured to receive the first portion 208 of the guided image beam having the first portion 210 of the beamlets and the second portion 212 of the beamlets. The input coupler 220 can also be configured to receive the second portion 214 of the guided image beam having the third portion 216 of the beamlets and the fourth portion 218 of the beamlets. FIG. 3A to FIG. 6BAs shown, the reflective inner surface 408 can be disposed on the back surface 223 of the input coupler 220 and, as described, can be configured to receive the first portion 210 of the beamlet and provide the reflected first portion 410 of the beamlet. Similarly, as described, the back surface 223 of the input coupler 220 can be configured to receive the third portion 216 of the beamlet and provide the reflected third portion 416 of the beamlet. Thus, as described, the reflected first portion 410 of the beamlet, the second portion 212 of the beamlet, the reflected third portion 416 of the beamlet, and the fourth portion 218 of the beamlet can exit from the input coupler bottom surface 227 at different angles.

[0077] The optical device 602 can include a first waveguide 630 having a first diffraction grating 632 that can be configured to receive the first portion 410 of the reflected beamlet and provide a first portion 636 of the diffracted beamlet. The first diffraction grating 632 can be configured to receive the second portion 212 of the beamlet and provide a second portion 638 of the diffracted beamlet. The first portion 636 of the diffracted beamlet and the second portion 638 of the diffracted beamlet together constitute a first portion 634 of the diffracted guided image beam that is configured to travel along the first waveguide 630 by quadruple internal reflection while rotating in opposite directions (e.g., in a spiral manner). For example, the first diffraction grating 632 can be disposed adjacent to and coplanar with the first waveguide top surface 635. The first waveguide 630 can include a first aperture expander 640 that is configured to receive the first portion 634 of the diffracted guided image beam and provide a first plurality of expanded image beams 648.

[0078] The first aperture expander 640 can be implemented as a second diffraction grating 646 that is configured to expand the first portion 634 of the diffracted guided image beam in a first dimension (e.g., laterally across the long axis 294 of the first waveguide 630) to provide a first plurality of expanded image beams 648 that can exit from the first waveguide bottom surface 637. The second diffraction grating 646 can be disposed adjacent to and coplanar with the first waveguide bottom surface 637. In this manner, the first diffraction grating 632 and the second diffraction grating 646 can be implemented as two diffraction elements with opposite optical powers to eliminate dispersion. The first waveguide 630 can be configured to receive the second portion 214 of the guided image beam and provide a transmitted second portion 244 of the guided image beam. The first waveguide 630 can be similar in some respects to the first waveguide 630 described with reference to FIG. FIG. 2A to FIG. 2B The first waveguide 230 .

[0079] For example, a diffraction grating such as the first diffraction grating 632 can be a passive optical element generally described as a diffractive optical element or a transmissive diffractive component having a partially reflective surface having a periodic structure (e.g., two-dimensional periodicity) that receives an incident light beam and provides multiple light beams at different angles, wherein the diffraction grating can be embedded in a light-guiding optical element 132 such as the first waveguide 630. As used herein, for example, a diffraction grating can be a refractive or reflective beam expander configured to receive an input beam on a first side and provide multiple output beams from a second side (wherein the output beams can be expanded in a first dimension (e.g., a lateral dimension)), and can be used to receive and redirect light beams, similar to reference Figure 2A In addition, a diffractive optical element such as a diffraction grating can also be used as an aperture expander, similar to the reference Figure 2A and parallel plurality of partially reflecting facets 246 in the first aperture expander 240 as described elsewhere.

[0080] The optical device 602 can include a second waveguide 650 having a third diffraction grating 652 that can be configured to receive the third portion 416 of the reflected beamlet and provide a third portion 656 of the diffracted beamlet. The third diffraction grating 652 can be configured to receive the fourth portion 218 of the beamlet and provide a fourth portion 658 of the diffracted beamlet. The third portion 656 of the diffracted beamlet and the fourth portion 658 of the diffracted beamlet together constitute a second portion 654 of the diffracted guided image beam that is configured to travel along the first waveguide 630 by quadruple internal reflection while rotating in opposite directions (e.g., in a spiral manner). For example, the third diffraction grating 652 can be disposed adjacent to and coplanar with the second waveguide top surface 655. The second waveguide 650 may include a second aperture expander 660 located in a second region 662 laterally displaced 664 from the first region 642 and configured to receive a second portion 654 of the diffracted guided image beam and provide a second plurality of expanded image beams 668 .

[0081] The second aperture expander 660 can be implemented as a fourth diffraction grating 666 that is configured to expand the second portion 654 of the diffracted guided image beam in a first dimension (e.g., laterally across the long axis 294 of the second waveguide 650) to provide a second plurality of expanded image beams 668 that can exit from the second waveguide bottom surface 657. The fourth diffraction grating 666 can be disposed adjacent to and coplanar with the second waveguide bottom surface 657. In this manner, the third diffraction grating 652 and the fourth diffraction grating 666 can be implemented as two diffraction elements with opposite optical powers to eliminate dispersion. The second waveguide 650 can be configured to receive the first plurality of expanded image beams 648 and provide a transmitted first plurality of expanded image beams 678. The second waveguide 650 can be similar in some respects to the reference FIG. 2A to FIG. 2B The second waveguide 250.

[0082] The first aperture expander 640 and the second aperture expander 660 may overlap laterally (e.g., horizontally as shown) by an overlap distance 690, which may be in the range of between 1% and 20% of the length of the first waveguide 630 and the second waveguide 650, which are preferably equal in length. The overlap distance 690 may preferably be in the range of between 5% and 10% of the length of the first waveguide 630. For example, the technical benefit of the overlap of the first aperture expander 640 and the second aperture expander 660 may contribute to the continuity of the combined image. Alternatively, the first aperture expander 640 and the second aperture expander 660 may not overlap, and thus the overlap distance 690 may be zero, where image continuity is not an issue.

[0083] The optical device 602 can include a third waveguide 270 having a third aperture expander 272 located in the third region 274 (e.g., oriented vertically) and configured to receive the transmitted first plurality of expanded image beams 678 and the second plurality of expanded image beams 668, and provide a third plurality of expanded image beams 280 to exit the third waveguide rear surface 273 toward an eye box 282 and an eye 284 of a user or wearer of the wearable device 110. In this manner, the third aperture expander 272 can be configured to expand the transmitted first plurality of expanded image beams 678 and the second plurality of expanded image beams 668 in a second dimension orthogonal to the first dimension (e.g., vertically across a vertical axis 296 of the third waveguide 270).

[0084] The first waveguide 630 may include a first homogenizer 686 disposed in a parallel plane that is vertically disposed approximately midway between the first waveguide top surface 635 and the first waveguide bottom surface 637, and horizontally (e.g., laterally) disposed between the first diffraction grating 632 and the first aperture expander 640. In particular, the first homogenizer 686 may be horizontally disposed in a position that may overlap with a portion of one or both of the first diffraction grating 632 and the second diffraction grating 646. Alternatively, the first homogenizer 686 may not overlap with any portion of the first diffraction grating 632 or the second diffraction grating 646. Similarly, the second waveguide 650 may include a second homogenizer 688 disposed in a parallel plane that is vertically disposed approximately midway between the second waveguide top surface 655 and the second waveguide bottom surface 657, and horizontally (e.g., laterally) disposed between the third diffraction grating 652 and the fourth diffraction grating 666. In particular, the second homogenizer 688 may be horizontally disposed in a position that may overlap a portion of one or both of the third diffraction grating 652 and the fourth diffraction grating 666. Alternatively, the second homogenizer 688 may not overlap any portion of the third diffraction grating 652 or the fourth diffraction grating 666.

[0085] According to an example, the optical device 602 may include a frame 148 (e.g., a structural element) configured to support the wearable device 110, the controller 112, the memory 114, the power management module 116, the battery 118, the image projector 120, the light guide 130 including two or more light guide optical elements 132 (e.g., the first waveguide 630, the second waveguide 650, the third waveguide 270), the optical engine 142, two or more of the first waveguide 630, the second waveguide 650, and the third waveguide 270 in relative positions to each other. In an example, the frame 148 may support the input coupler 220 and the first waveguide 630 so that the first interface 213 between the input coupler 220 and the first waveguide 630 includes a first air gap. In an example, the frame 148 may support the first waveguide 630 and the second waveguide 650 so that the second interface 215 between the first waveguide 630 and the second waveguide 650 includes a second air gap. In an example, the frame 148 may support the second waveguide 650 and the third waveguide 270 such that the third interface 217 between the second waveguide 650 and the third waveguide 270 includes a third air gap. In an example, the frame 148 may support the first waveguide 630 and the second waveguide 650 such that the first waveguide 630 and the second waveguide 650 may be completely hidden within the frame 148. FIG. 6A to FIG. 6B As shown, the first waveguide 630 may include a diffractive element and the second waveguide 650 may include a diffractive element. Thus, the optical device 602 and the light guide 130 may include a second stacked waveguide arrangement of a diffractive type.

[0086] Fig. 7A Shown are front plan views of optical systems including light guides according to various examples. Figure 7B Various examples are shown including Fig. 7A 1. A side plan view of an optical system of a light guide. According to an example, optical device 702 may include a first input coupler 220A configured to receive a first collimated image beam 206A from a first image projector 120A and provide a first portion of the guided image beam. Optical device 702 may include a second input coupler 220B configured to receive a second collimated image beam 206B from a second image projector 120B and provide a second portion of the guided image beam.

[0087] As reference Figures 1 to 7B As described, the first waveguide 730 can be configured to receive and expand the first portion 208 of the guided image beams based on the first image field 126A in the first dimension 294 and provide a first plurality of expanded image beams 248. The second waveguide 750 can be disposed adjacent to the first waveguide 730 and configured to receive and expand one of the transmitted second portion 244 of the guided image beams and the second portion 214 of the guided image beams corresponding to the second image field 126D different from the first image field in the first dimension and provide a second plurality of expanded image beams 268. The second waveguide 750 can be configured to receive the first plurality of expanded image beams and provide a transmitted first plurality of expanded image beams 278. The third waveguide 270 can be disposed adjacent to the second waveguide 750 on the side opposite to the first waveguide 730. The third waveguide 270 can be configured to receive and expand the transmitted first plurality of expanded image beams 278 and the second plurality of expanded image beams 268 in the second dimension 296 to provide a third plurality of expanded image beams 280. The first waveguide 730 may have a first aperture expander 740 located in a first region 742. The second waveguide 750 may have a second aperture expander 760 located in a second region 762 that is laterally displaced 764 from the first region 742. The first aperture expander 740 and the second aperture expander 760 may overlap laterally (e.g., horizontally as shown) by an overlap distance 790 that may range, for example, between 1% and 20% of the length of the first waveguide 730 and the second waveguide 750, which are preferably equal in length.

[0088] The first input coupler 220A may include a first input coupler back surface 223A having a reflective surface similar to the reflective surface 408. Similarly, the second input coupler 220B may include a second input coupler back surface 223B having a reflective surface similar to the reflective surface 408. The first waveguide 230 may include a first homogenizer 786 disposed in parallel planes vertically disposed approximately midway between the first waveguide top surface 735 and the first waveguide bottom surface 737, and horizontally (e.g., laterally) disposed between the first mirror or first diffraction grating and the first aperture expander. Similarly, the second waveguide 750 may include a second homogenizer 788 disposed in parallel planes vertically disposed approximately midway between the second waveguide top surface 755 and the second waveguide bottom surface 757, and horizontally (e.g., laterally) disposed between the second mirror or third diffraction grating and the second aperture expander. Various light homogenizers may be used alone or in combination with one another to provide improved illumination uniformity as well as other benefits.

[0089] According to various examples disclosed herein, the first waveguide 730 may include a reflective element, and the second waveguide 750 may include a reflective element, so that the optical device 702 and the light guide 130 may include a first stacked waveguide arrangement 761 of a reflective type, also in FIG. 2A to FIG. 2B Alternatively, the first waveguide 730 may include a diffractive element and the second waveguide 750 may include a diffractive element, so that the optical device 702 and the light guide 130 may include a second stacked waveguide arrangement 763 of a reflective type, also in FIG. 6A to FIG. 6B In another alternative, the first waveguide 730 may include a reflective element and the second waveguide 750 may include a diffractive element, so that the optical device 702 and the light guide 130 may include a third stacked waveguide arrangement 765 of a mixed reflective and diffractive type. In yet another alternative, the first waveguide 730 may include a diffractive element and the second waveguide 750 may include a reflective element, so that the optical device 702 and the light guide 130 may include a fourth stacked waveguide arrangement 767 of a mixed diffractive and reflective type.

[0090] like Figures 1 to 7BAs shown, the optical device 702 may include a third stacked waveguide arrangement 765, which may include a first waveguide 730 having a first mirror 232, the first mirror 232 being configured to receive the first portion 208 of the guided image beam and provide a first portion 234 of the reflected guided image beam. The first waveguide 730 may include a first aperture expander 740 located in a first region 742. The first aperture expander 740 may include a first plurality of partially reflecting facets 246 disposed in the first region 742. The first mirror 232 and the first plurality of partially reflecting facets 246 may be parallel to each other and disposed at a first angle 239 relative to a long axis 294 of the first waveguide 730. The first aperture expander 740 may be configured to receive the first portion 234 of the reflected guided image beam and provide a first plurality of expanded image beams 248, wherein the first waveguide 730 may be configured to receive the second portion 214 of the guided image beam and provide the second portion 244 of the transmitted guided image beam. The optical device 702 may include a second waveguide 750 further including a third diffraction grating 652 configured to receive the second portion 244 of the transmitted guided image beam and provide a second portion 654 of the diffracted guided image beam. The second waveguide 750 may include a second aperture expander 760 located in a second region 762 that is laterally displaced 764 from the first region 742. The second aperture expander 760 may be configured to receive the second portion 654 of the diffracted guided image beam and provide a second plurality of expanded image beams 668, wherein the second waveguide 730 may be configured to receive the first plurality of expanded image beams 648 and provide a transmitted first plurality of expanded image beams 678. Thus, the first waveguide 730 may include a reflective element and the second waveguide 750 may include a diffractive element, such that the optical device 702 and the light guide 130 may include a third stacked waveguide arrangement 765 having a mixed reflective and diffractive type.

[0091] The optical device 702 may include a fourth stacked waveguide arrangement 767, which may include a first waveguide 730 having a first diffraction grating 632 configured to receive the first portion 208 of the guided image beam and provide a first portion of the diffracted guided image beam. The first waveguide 730 may include a first aperture expander 740 located in a first region 742. The first aperture expander 740 may include a second diffraction grating 646 disposed in the first region 742. The first aperture expander 740 may be configured to receive the first portion 634 of the diffracted guided image beam and provide a first plurality of expanded image beams 648, wherein the first waveguide 730 is configured to receive the second portion 214 of the guided image beam and provide a second portion 244 of the transmitted guided image beam. The second waveguide 750 may further include a second mirror 252 configured to receive the second portion 244 of the transmitted guided image beam and provide a second portion 254 of the reflected guided image beam. The second aperture expander 760 may be located in a second region 762 that is laterally displaced 764 from the first region 742. The second aperture expander 760 may be configured to receive the reflected second portion 254 of the guided image beams and provide a second plurality of expanded image beams 268, wherein the second waveguide 750 is configured to receive the first plurality of expanded image beams 248 and provide a transmitted first plurality of expanded image beams 278. Thus, the first waveguide 730 may include a diffractive element and the second waveguide 750 may include a reflective element, so that the optical device 702 and the light guide 130 may include a fourth stacked waveguide arrangement 767 of a mixed diffractive and reflective type.

[0092] The various features described separately above can be combined together unless they are incompatible with each other. Figures 1 to 5 Each feature and reference FIG. 6A to FIG. 6B as well as FIG. 7A to FIG. 7B If the features described are technically compatible, such features may be combined.

[0093] The terms used herein are only used for the purpose of describing specific embodiments, and are not intended to limit the present invention. As used herein, unless the context clearly indicates otherwise, the singular form and "the" are also intended to include plural forms. It will also be understood that when the terms "include", "contain" and / or "comprise" are used in this specification, they specify the existence of the features, integral bodies, steps, operations, elements and / or parts, but do not exclude the existence or addition of one or more other features, integral bodies, steps, operations, elements, parts and / or their groups. In addition, terms such as top, bottom, above, adjacent, below, vertical, horizontal, lateral, side, front, rear, etc. can describe the relative placement of elements in the specific views shown in the accompanying drawings, and should not be considered restrictive. For example, when a view or element is reversed, such terms can be applied inversely.

[0094] The corresponding structures, materials, actions and equivalents of all means or steps plus function elements (if any) in the appended claims are intended to include any structure, material or action for performing functions in combination with other claimed elements specifically claimed. A description of the present invention has been given for the purpose of illustration and description, but it is not intended to be exhaustive or limited to the present invention in the disclosed form. Many modifications and variations will be obvious to those of ordinary skill in the art without departing from the scope and spirit of the present invention. The selection and description of various embodiments are in order to best illustrate the principles and practical applications of the present invention, and to enable other persons of ordinary skill in the art to understand the present invention so that various embodiments with various modifications are suitable for the specific purposes considered.

Claims

1. An optical device, comprising: a first waveguide configured to receive and expand in a first dimension a first portion of the guided image beam based on the first image field and provide a first plurality of expanded image beams; a second waveguide disposed adjacent to the first waveguide, the second waveguide configured to receive and expand in the first dimension one of a second portion of the transmitted guided image beams and a second portion of the guided image beams corresponding to a second image field different from the first image field, and provide a second plurality of expanded image beams, the second waveguide configured to receive the first plurality of expanded image beams and provide the transmitted first plurality of expanded image beams; as well as A third waveguide is disposed adjacent to the second waveguide on a side opposite to the first waveguide, the third waveguide being configured to receive and expand the transmitted first and second plurality of expanded image beams in a second dimension to provide a third plurality of expanded image beams.

2. The optical device according to claim 1, in, The first waveguide further comprises: a first mirror configured to receive the first portion of the directed image beam and provide a first portion of a reflected directed image beam; and a first aperture expander located in the first region, the first aperture expander configured to receive a first portion of the reflected guided image beam and provide the first plurality of expanded image beams, wherein the first waveguide is configured to receive a second portion of the guided image beam and provide a transmitted second portion of the guided image beam; and Wherein, the second waveguide further comprises: a second mirror configured to receive a second portion of the transmitted directed image beam and to provide a second portion of the reflected directed image beam; and a second aperture expander located in a second region laterally displaced from the first region, the second aperture expander configured to receive a second portion of the reflected guided image beam and provide a second plurality of expanded image beams, Wherein the second waveguide is configured to receive the first plurality of extended image beams and provide a transmitted first plurality of extended image beams.

3. The optical device according to claim 2, in, The first aperture expander includes a first plurality of partially reflecting facets disposed in the first region, the first mirror and the first plurality of partially reflecting facets being parallel to each other and disposed at a first angle relative to a long axis of the first waveguide, and The second aperture expander comprises a second plurality of partially reflecting facets arranged in the second region, the second mirror and the second plurality of partially reflecting facets are parallel to each other and are arranged at a second angle relative to the long axis of the second waveguide, and the second angle is different from the first angle.

4. The optical device according to claim 3, in, A first portion of the reflected guided image beam is reflected within the first waveguide by total internal reflection between a first waveguide front surface and a first waveguide rear surface, and Wherein a second portion of the reflected guided image beam is reflected within the second waveguide by total internal reflection between a second waveguide front surface and a second waveguide rear surface.

5. The optical device according to claim 1, in, The first waveguide further comprises: a first diffraction grating configured to receive a first portion of the guided image beam and provide a first portion of a diffracted guided image beam; a first aperture expander located in the first region, the first aperture expander configured to receive a first portion of the diffracted guided image beam and provide the first plurality of expanded image beams, wherein the first waveguide is configured to receive a second portion of the guided image beam and provide a transmitted second portion of the guided image beam; and Wherein, the second waveguide further comprises: a third diffraction grating configured to receive a second portion of the transmitted guided image beam and to provide a second portion of a diffracted guided image beam; a second aperture expander located in a second region laterally displaced from the first region, the second aperture expander configured to receive a second portion of the diffracted guided image beam and provide a second plurality of expanded image beams, Wherein the second waveguide is configured to receive the first plurality of extended image beams and provide a transmitted first plurality of extended image beams.

6. The optical device according to claim 5, in, the first aperture expander comprises a second diffraction grating configured to receive a first portion of the diffracted guided image beam and provide the first plurality of expanded image beams, and Wherein the second aperture expander comprises a fourth diffraction grating configured to receive a second portion of the diffracted guided image beam and provide the second plurality of expanded image beams.

7. The optical device according to claim 6, in, A first portion of the diffracted guided image beam is reflected within the first waveguide by total internal reflection between the first waveguide front surface and the first waveguide rear surface, and Wherein a second portion of the diffracted guided image beam is reflected within the second waveguide by total internal reflection between a second waveguide front surface and a second waveguide rear surface.

8. The optical device of claim 1, further comprising one of the following: A third stacked waveguide arrangement comprising: The first waveguide further comprises: a first mirror configured to receive a first portion of the guided image beam and to provide a first portion of a reflected guided image beam; and a first aperture expander located in a first region, the first aperture expander comprising a first plurality of partially reflecting facets disposed in the first region, the first mirror and the first plurality of partially reflecting facets being parallel to each other and disposed at a first angle relative to a long axis of the first waveguide, the first aperture expander being configured to receive a first portion of the reflected guided image beam and to provide the first plurality of expanded image beams, wherein the first waveguide is configured to receive a second portion of the guided image beam and to provide a second portion of a transmitted guided image beam; and The second waveguide further comprises: a third diffraction grating configured to receive a second portion of the transmitted guided image beam and to provide a second portion of the diffracted guided image beam; and a second aperture expander located in a second region laterally displaced from the first region, the second aperture expander configured to receive the second portion of the diffracted guided image beam and to provide a second plurality of expanded image beams, wherein the second waveguide is configured to receive the first plurality of expanded image beams and to provide a transmitted first plurality of expanded image beams; and A fourth stacked waveguide arrangement comprising: The first waveguide further comprises: a first diffraction grating configured to receive a first portion of the guided image beam and provide a first portion of a diffracted guided image beam; and a first aperture expander located in a first region, the first aperture expander comprising a second diffraction grating disposed in the first region, the first aperture expander configured to receive the first portion of the diffracted guided image beam and provide the first plurality of expanded image beams, wherein the first waveguide is configured to receive a second portion of the guided image beam and provide a second portion of a transmitted guided image beam; and The second waveguide further comprises: a second mirror configured to receive a second portion of the transmitted guided image beam and to provide a second portion of the reflected guided image beam; and a second aperture expander located in a second region laterally displaced from the first region, the second aperture expander configured to receive the second portion of the reflected guided image beam and to provide a second plurality of expanded image beams, wherein the second waveguide is configured to receive the first plurality of expanded image beams and to provide a transmitted first plurality of expanded image beams.

9. The optical device according to claim 8, in, one of the first portion of the reflected guided image beam and the first portion of the diffracted guided image beam is reflected within the first waveguide by total internal reflection between a first waveguide front surface and a first waveguide rear surface, and wherein one of the second portion of the diffracted guided image beam and the second portion of the reflected guided image beam is reflected within the second waveguide by total internal reflection between a second waveguide front surface and a second waveguide rear surface.

10. The optical device according to claim 1, in, The third waveguide further comprises: A third aperture expander is located in the third region and is configured to receive the transmitted first plurality of expanded image beams and the second plurality of expanded image beams and provide a third plurality of expanded image beams to exit the third waveguide rear surface.

11. The optical device according to claim 10, in, The third aperture expander includes a third plurality of partially reflecting facets that are parallel to each other and disposed at a third angle that is inclined relative to the third waveguide front surface, and Wherein, the transmitted first plurality of expanded image beams and the second plurality of expanded image beams are reflected by total internal reflection between the third waveguide front surface and the third waveguide rear surface.

12. The optical device according to claim 1, wherein: The first dimension is orthogonal to the second dimension.

13. The optical device according to claim 1, further comprising: an input coupler configured to receive the collimated image beam from the image projector and to provide a first portion of the directed image beam and to provide a second portion of the directed image beam, wherein the input coupler comprises a reflective inner surface, the input coupler being configured to receive a first portion of the guided image beam having a first portion of beamlets and a second portion of beamlets, the input coupler being configured to receive the second portion of the guided image beam having a third portion of beamlets and a fourth portion of beamlets, the reflective inner surface being configured to receive the first portion of the beamlets and provide a reflected first portion of the beamlets, the reflective inner surface being configured to receive the third portion of the beamlets and provide a reflected third portion of the beamlets, wherein the first waveguide is configured to receive a first portion of the reflected beamlets, the first portion of the reflected beamlets being configured to propagate along the first waveguide in a quadruple helix manner and rotate in a first direction, the first waveguide is configured to receive a second portion of the beamlets, the second portion of the beamlets being configured to propagate along the first waveguide in a quadruple helix manner and rotate in a second direction opposite to the first direction, the first portion of the reflected beamlets and the second portion of the beamlets being expanded to provide the first plurality of expanded image beams, and wherein the second waveguide is configured to receive a third portion of the reflected sub-beam, the third portion of the reflected sub-beam is configured to propagate along the second waveguide in a quadruple helix manner and rotate in a first direction, the second waveguide is configured to receive a fourth portion of the sub-beam, the fourth portion of the sub-beam is configured to propagate along the second waveguide in a quadruple helix manner and rotate in a second direction opposite to the first direction, and the third portion of the reflected sub-beam and the fourth portion of the sub-beam are expanded to provide the second plurality of expanded image beams.

14. The optical device according to claim 13, further comprising: an image projector disposed adjacent to the input coupler and configured to provide a collimated image beam corresponding to an image field based on a digital image, the collimated image beam comprising a first portion of the guided image beam corresponding to the first image field, the collimated image beam comprising a second portion of the guided image beam corresponding to the second image field, wherein the collimated image beam is collimated to infinity.

15. The optical device according to claim 1, further comprising: a first input coupler configured to receive a first collimated image beam from a first image projector and to provide a first portion of the directed image beam; as well as a second input coupler configured to receive a second collimated image beam from a second image projector and to provide a second portion of the directed image beam, wherein the first input coupler comprises a first reflective inner surface, the first input coupler being configured to receive a first portion of the guided image beam having a first portion of beamlets and a second portion of beamlets, the first reflective inner surface being configured to receive the first portion of the beamlets and provide a reflected first portion of the beamlets, wherein the first waveguide is configured to receive a first portion of the reflected beamlets, the first portion of the reflected beamlets being configured to propagate along the first waveguide in a quadruple helix manner and rotate in a first direction, the first waveguide is configured to receive a second portion of the beamlets, the second portion of the beamlets being configured to propagate along the first waveguide in a quadruple helix manner and rotate in a second direction opposite to the first direction, the first portion of the reflected beamlets and the second portion of the beamlets being expanded to provide the first plurality of expanded image beams, wherein the second input coupler comprises a second reflective inner surface, the second input coupler is configured to receive the second portion of the guided image beam having a third portion of beamlets and a fourth portion of beamlets, the second reflective inner surface is configured to receive the third portion of beamlets and provide a reflected third portion of beamlets, and wherein the second waveguide is configured to receive a third portion of the reflected sub-beam, the third portion of the reflected sub-beam is configured to propagate along the second waveguide in a quadruple helix manner and rotate in a first direction, the second waveguide is configured to receive a fourth portion of the sub-beam, the fourth portion of the sub-beam is configured to propagate along the second waveguide in a quadruple helix manner and rotate in a second direction opposite to the first direction, and the third portion of the reflected sub-beam and the fourth portion of the sub-beam are expanded to provide the second plurality of expanded image beams.

16. The optical device according to claim 15, further comprising: a first image projector disposed adjacent to the first input coupler and configured to provide a first collimated image beam corresponding to the first image field based on at least a first portion of a digital image, the first collimated image beam comprising a first portion of the guided image beam; as well as a second image projector disposed adjacent to the second input coupler and configured to provide a second collimated image beam corresponding to the second image field based on at least a second portion of the digital image, Wherein, the first collimated image beam and the second collimated image beam are collimated to infinity.

17. The optical device of claim 1, further comprising at least one of the following: a first homogenizer disposed in a plane between the first waveguide top surface and the first waveguide bottom surface; and A second homogenizer is disposed in a plane between the second waveguide top surface and the second waveguide bottom surface.

18. The optical device of claim 1, further comprising at least one of the following: a first retarder wave plate disposed between the first waveguide bottom surface and the second waveguide top surface, the first retarder wave plate configured to receive at least one of the first plurality of expanded image beams and the second portion of the transmitted guided image beam and provide a first retarder output that is at least one of rotated and depolarized; and A second retarder wave plate is disposed between the second waveguide bottom surface and the third waveguide top surface, the second retarder wave plate being configured to receive at least one of the second plurality of extended image beams and the transmitted first plurality of extended image beams and provide a second retarder output, the second retarder output being at least one of rotated and depolarized.

19. The optical device of claim 1, further comprising at least one of the following: a first dielectric coating disposed on a bottom surface of the input coupler; a second dielectric coating disposed on a bottom surface of the first waveguide; as well as A third dielectric coating is disposed on the bottom surface of the second waveguide.

20. The optical device of claim 1, comprising at least one of the following: a frame configured to support the first waveguide, the second waveguide, and the third waveguide in positions relative to each other, wherein The first waveguide and the second waveguide are completely hidden in the frame; a first interface between the input coupler and the first waveguide, the first interface comprising a first air gap; a second interface between the first waveguide and the second waveguide, the second interface comprising a second air gap; as well as A third interface is between the second waveguide and the third waveguide, wherein the third interface comprises a third air gap.

Images