Folding 2D extended optical waveguide

Abstract

The optical waveguide includes a first waveguide and a second waveguide facing each other (e.g., they are parallel or have an acute angle therebetween). The first waveguide has an aperture configured to receive an input light beam. The first waveguide also has a first set of facets configured to receive the input light beam and at least partially reflect the input light beam as a first light beam. The first waveguide also has a decoupling element configured to receive the first light beam and reflect the first light beam out of the first waveguide. The second waveguide has a coupling element configured to receive the first light beam and reflect the first light beam toward a second set of facets of the second waveguide configured to at least partially reflect the first light beam as a second light beam and couple the second light beam out of the second waveguide.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 547,696, filed November 8, 2023. The entire disclosure of U.S. Provisional Application No. 63 / 547,696 is incorporated herein by reference. Background Technology

[0003] This disclosure generally relates to systems and methods for presenting information to users, and more specifically, to optical systems and near-eye displays for presenting information to users.

[0004] Unless otherwise stated herein, the materials described in this section are not prior art to the claims of this application and will not be considered prior art simply because they are included in this section.

[0005] In near-eye displays, a very wide field of view (FoV) can be achieved by using two light guide elements (e.g., one in each of the two extended dimensions). Typically, the light guide elements are positioned end-to-end; however, in the context of head-mounted display units such as smart glasses or virtual reality systems, such an end-to-end arrangement can be cumbersome. Summary of the Invention

[0006] This paper describes an optical waveguide with folded 2D extension. The optical waveguide includes a first waveguide and a second waveguide. The first waveguide has a pair of parallel first primary surfaces and an aperture disposed on one of the first primary surfaces, configured to receive an input light beam. The first waveguide also has a first set of facets disposed along a first axis between the first primary surfaces, the first set of facets being configured to receive the input light beam and reflect the input light beam at least partially as a first beam. The first waveguide also has a coupling element configured to receive the first beam and reflect the first beam out of the first waveguide. The second waveguide has a pair of parallel second primary surfaces, wherein at least one of the second primary surfaces faces at least one of the first primary surfaces. The second waveguide also has a coupling element configured to receive the first beam and reflect the first beam toward a second set of facets of the second waveguide. The second set of facets is disposed along a second axis between the second primary surfaces and is configured to receive a second beam and reflect the first beam at least partially as a second beam and couple the second beam out of the second waveguide.

[0007] This article also describes a device. The device includes the optical waveguide discussed above and a projector configured to generate an input beam.

[0008] The foregoing overview is illustrative only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, other aspects, embodiments, and features will become apparent from the accompanying drawings and the following detailed description. In the drawings, similar reference numerals indicate the same or functionally similar elements. Attached Figure Description

[0009] Figure 1 Examples of systems including optical waveguides with folded 2D extensions, according to various examples of this disclosure, are shown.

[0010] Figure 2 Examples of optical waveguides with folded 2D extensions according to various examples of this disclosure are shown.

[0011] Figure 3 Various examples based on this disclosure are shown. Figure 2 An example perspective view of the first optical waveguide element of an optical waveguide.

[0012] Figure 4 Various examples based on this disclosure are shown. Figure 2 Side view of an optical waveguide.

[0013] Figure 5 Various examples based on this disclosure are shown. Figure 2 An example perspective view of the second optical guiding optical element of the optical waveguide.

[0014] Figure 6 Various examples based on this disclosure are shown. Figure 2 Front view of the optical waveguide.

[0015] Figure 7 Another example of an optical waveguide with folded 2D extension is shown, according to various examples of this disclosure.

[0016] Figure 8 Another example of an optical waveguide with folded 2D extension is shown, according to various examples of this disclosure.

[0017] Figure 9 Another example of an optical waveguide with folded 2D extension is shown, according to various examples of this disclosure. Detailed Implementation

[0018] In the following description, numerous specific details, such as particular structures, components, materials, dimensions, processing steps, and techniques, are set forth to provide an understanding of various embodiments of this application. However, those skilled in the art will recognize that various embodiments of this application can be practiced without these specific details. In other instances, well-known structures or processing steps have not been described in detail to avoid obscuring the application.

[0019] Wearable devices, such as near-eye displays and / or smart glasses, can be implemented using systems and methods described in accordance with this disclosure, as will be described in more detail below. This system can efficiently provide users with high-quality optical information in a variety of applications.

[0020] Figure 1 A block diagram illustrating an example of an optical system 100 comprising a folded optical waveguide is shown. The optical system 100 may include two or more devices or components. The optical system 100 can typically be implemented as a hybrid system including various electronic components, optical components, and electro-optical components. As will be described in more detail below, the optical system 100 may include a wearable device 102, such as one or more near-eye displays or smart glasses, which may be worn on or around a user's head to transmit optical information to one or more of the user's eyes.

[0021] For example, wearable device 102 may include controller 104 having memory 106, wherein controller 104 may be configured to: send and receive electrical signals to and from various other components in optical system 100, execute program instructions stored in memory 106 to process and provide information, operate wearable device 102, and interact with other systems outside wearable device 102. Controller 104 may include microcontroller, processor, various discrete components, programmable logic devices, and / or various interface circuits that can access memory 106, which may be removable, replaceable, programmable, and reprogrammable to update instructions to controller 104.

[0022] The wearable device 102 may also include a power management module 108 with a battery 110, wherein the power management module 108 can be configured to charge, discharge, and monitor the battery's power usage. For example, various components of the wearable device 102, including a controller 104, one or more image projectors 112 (e.g., projection optics or PODs), a graphics engine 114 with one or more digital images 116, and an image capture device 115, can receive power from the battery 110.

[0023] Each of the image projectors 112 can be configured to generate a collimated image beam based on a digital image 116. The collimated image beam can be an illumination representation of a digital image with an image field, which is a two-dimensional representation of a digital image based on a single graphic image (e.g., a still image) or a series of graphic images (e.g., moving images). The collimated image beam can be collimated up to infinity.

[0024] The wearable device 102 may also include a light-guiding optics element 118 (e.g., LOE, also defined as a waveguide WG), which includes a transparent material configured to receive and propagate light, wherein light can enter and exit various outer and inner surfaces of the light-guiding optics element 118. For example, the transparent material including the light-guiding optics element 118 may include optical glass or other suitable materials that can be transformed into complex optical structures using processes that may include coating, stacking, slicing, polishing, and shaping the transparent material. For example, the process may include adding partially reflective or totally reflective materials, such as a mirror coating. Similarly, the process may also include adding partially opaque or completely opaque materials, such as light-blocking coatings.

[0025] The graphics engine 114 can be coupled to the image projector 112 and the light guide optics 118. The graphics engine 114 can be configured to directly operate the image projector 112 under the guidance of the controller 104. For example, the graphics engine 114 can provide graphics processing of the digital image before the illumination representation of the digital image is projected by the image projector 112.

[0026] Image capture device 115 may include a video camera or other electrical components configured to capture at least a portion of the external environment surrounding the user. Graphics engine 114 may be coupled to image capture device 115 and may generate digital images, for example, using video or image input or other data obtained by image capture device 115 when the device is operating in a mode that utilizes the surrounding external environment.

[0027] The wearable device 102 may also include a frame 120 (e.g., a structure) for supporting and holding one or more elements of the wearable device 102. See also, for example, [reference needed]. Figures 2 to 5The frame 120 can support and hold the image projector 112 in a position adjacent to the first light-guiding optical element (e.g., light-guiding optical element 118a). Similarly, the frame 120 can support a second light-guiding optical element (e.g., light-guiding optical element 118b) in a position adjacent to the light-guiding optical element 118a and separated by a gap 119 (e.g., an air gap or a gap filled with adhesive or another material). In this way, the frame 120 can support and hold the image projector 112 and the plurality of light-guiding optical elements 118 on or around the user's head. Reference is made herein to the orientation of the various elements relative to each other. Such reference may also include reference to the various elements of the wearable device 102 being supported by the frame 120 or to the various elements of the wearable device 102 in a reference coordinate system (e.g., the X, Y, Z axes).

[0028] The optical system 100 may also include a host computer 122, which may include a processor 124 configured to read and execute operations based on instructions 126 stored in a computer-readable medium 128. Instructions 126 may include at least some instructions provided to the controller 104 and stored in memory 106. The host computer 122 may communicate with one or more components of the wearable device 102 via a signal and power bus 130. In this way, the host computer 122 may provide power to charge the battery 110, provide instructions to the controller 104 and various other components of the wearable device 102 and receive status from the controller 104 and various other components of the wearable device 102, provide digital image data to the graphics engine 114, and receive and process video or image data captured by the image capture device 115.

[0029] Figures 2 to 6 An example of a folded optical waveguide 200 (hereinafter referred to as "waveguide" 200) with an image projector 112 mounted thereto is shown for reference. Waveguide 200 includes two optical guiding elements 118, such as optical guiding element 118a and optical guiding element 118b. Optical guiding elements 118a and 118b are considered folded because they have two main surfaces facing each other. In other words, optical guiding element 118a is arranged parallel to or at an acute angle to optical guiding element 118b. The user's line of sight typically passes sequentially through both optical guiding elements 118a and 118b.

[0030] Optical guide elements 118a and 118b can be optically independent via their respective main surfaces, except through coupling elements 208 and 210, which are configured together to guide a light beam from optical guide element 118a to optical guide element 118b. A three-dimensional Cartesian coordinate system (e.g., X, Y, and Z axes) is shown. For clarity, the same coordinate system is always used. The coordinate system used may vary (e.g., axes and orientations) without departing from the scope of this disclosure.

[0031] An input beam from image projector 112 enters the optical guide element 118a of waveguide 200 through aperture 202. In the example shown, aperture 202 is disposed on a main surface (e.g., one of two main surfaces) of optical guide element 118a. In some implementations, aperture 202 may be disposed on other surfaces or objects (e.g., coupling prisms). The input beam may also be or alternatively directed by a mirror 304 within optical guide element 118a. Figures 7 to 9 Alternatively, it can be guided by a coupling prism attached to the light-guiding optical element 118a. If a coupling prism is implemented, the aperture 202 can be set on the coupling prism.

[0032] An input light beam propagates toward a first set of facets 204 of the optical guide optics 118a via total internal reflection (TIR) ​​between the main surfaces of waveguide 200. The first set of facets 204 may be perpendicular or inclined to the outer surface of waveguide 200 and are configured to at least partially reflect the input light beam toward a second set of facets 206 of the optical guide optics 118b via an output element 208 and an input element 210 (e.g., a coupling mirror, prism, or other element that can be used to guide or reflect the light beam from the optical guide optics 118a to the optical guide optics 118b). In some embodiments, the optical guide optics 118a may include the output element 208, and the optical guide optics 118b may include the input element 210. In other embodiments, one or both of the output element 208 and the input element 210 may be components separate from their respective optical guide optics 118. In some embodiments, the outgoing element 208 and the incoming element 210 may together include separate components that may be attached to the ends of the light-guiding optical elements 118a and 118b to facilitate guiding the propagating light beam from the light-guiding optical element 118a to the light-guiding optical element 118b.

[0033] A beam of light reflected by the first set of facets 204 propagates via TIR between the first set of facets 204 and the coupling element 208 (which then guides the beam toward the coupling element 210). The coupling element 210 guides the beam toward the second set of facets 206. The second set of facets 206 may be tilted to the outer surface of the waveguide 200 and is configured to direct the beam, for example, toward the eyebox 132 (…). Figure 6 At least partially, the waveguide 200 is reflected. To generate a uniform image, the cross section of the waveguide 200 can be fully illuminated.

[0034] The input beam generally propagates from the coupling element (e.g., a mirror or prism) along the light guide optics 118a toward the first set of facets 204 (the input beam may be reflected via TIR in multiple directions, but generally travels toward the first set of facets 204). When the input beam is partially reflected by the first set of facets 204, the input beam becomes a first beam, which also generally propagates toward the coupling element 208 or prism along the light guide optics 118a (the first beam may be reflected via TIR in multiple directions, but generally travels toward the coupling element 208 or prism). When the first beam is guided by the coupling element 208 or prism (e.g., by reflection or other adjustment of the beam direction), it generally propagates toward the coupling element 210. When the first beam is guided by the coupling element 210 (e.g., by reflection or other adjustment of the beam direction), it generally propagates toward the second set of facets 206 along the light guide optics 118b (it may be reflected via TIR in multiple directions, but generally travels toward the second set of facets 206). When the first beam is partially reflected by the second set of facets 206, it becomes the second beam. The second beam generally propagates along and out of the light guide optics 118b (e.g., from the waveguide 200 in a direction away from or opposite to the adjacent main surface of the light guide optics 118a). The propagation direction may be angled different from the axis without departing from the scope of this disclosure.

[0035] As used herein, each group of facets or each set of facets may include mutually parallel and partially reflective optical elements (e.g., facets) of a plurality of planes spaced apart from each other. Thus, each of the facets in a respective group may be parallel to each other and set at the same vertical or tilt angle. Furthermore, the facets described herein may include angle-selective coatings and may be controlled to have multiple states (e.g., on / off) or to vary the level of reflectivity and / or transmittance of each facet or cooperative set of facets in the structure.

[0036] Optical elements 118a and 118b can be bonded together, for example, by adhesive or other materials. The bonding can create a gap 119 between the optical elements 118a and 118b, such as an air gap in some embodiments. In some embodiments, the gap 119 may comprise material 404 (…). Figure 9 The material 404 is configured to block light transmission between the light-guiding optical elements 118a and 118b except via the coupling-out element 208 and the coupling-in element 210. In some embodiments, the gap 119 may alternatively have low transmittance or the material 404 may include low transmittance. Material 406 ( Figure 9 (e.g., a light-blocking layer or coating) may also be added, or alternatively, to the outer surface of the light-guiding optical element 118a, for example, to prevent light from entering the waveguide 200 from the external environment. In some embodiments, materials 404 and 406 may include opaque materials.

[0037] Although for clear purposes, optical guide elements 118a and 118b are in Figures 2 to 5 They are shown as having similar or identical surface areas for their main surfaces, but in some embodiments, they may have main surfaces with different surface areas. For example, Figure 6 A front view of waveguide 200 is shown, for example, as would be seen from a user's perspective, where the surface areas of the main surfaces of light-guiding optical elements 118a and 118b are different. In some embodiments, for example, as... Figure 6 As shown, the main surface of the optical guide element 118a may have a larger surface area than the main surface of the optical guide element 118b. In other embodiments, the main surface of the optical guide element 118a may have a smaller surface area than the main surface of the optical guide element 118b. In other embodiments, the main surface of the optical guide element 118a may have the same surface area as the main surface of the optical guide element 118b.

[0038] The surface area of ​​the main surfaces of optical guide elements 118a and 118b can reflect the working surface area. The difference in the working surface area of ​​optical guide elements 118a and 118b can alternatively be defined by the positions of facets 204 and 206.

[0039] Figure 7 A folded optical waveguide 300 (hereinafter referred to as "waveguide" 300) with an image projector 112 mounted thereto and a user's eye are shown for reference. Waveguide 300 includes components similar to those of waveguide 200, and therefore similar reference numerals are used where applicable.

[0040] like Figure 7 As shown, waveguide 300 includes a prism 302 disposed in a gap 119 between optical guide optics 118a and 118b (e.g., near the coupling-out element 208 and coupling-in element 210). For example, prism 302 may include a material configured to correct or compensate for dispersion caused by the waveguide material to guide a beam from coupling-out element 208 to coupling-in element 210. In some embodiments, coupling-out element 208 may be used alternatively in conjunction with prism 302 (or as part of prism 302) to guide a beam toward coupling-in element 210. Prism 302 may include a material selected to correct or compensate for dispersion in the waveguide and may include a block, wedge, or other configuration comprising two or more materials or prisms. In embodiments, using two prisms allows optical guide optics 118a and 118b to be parallel to each other rather than at an acute angle, even, for example, as... Figure 4 As shown.

[0041] In some embodiments, the gap 119 in the waveguide 300 can be used to mount additional components of the optical system 100, such as other electronic components, processors, etc., thereby enabling a more compact design. Furthermore, an image projector 112 can be mounted within the gap 119, and the aperture 202 can be positioned on the inner main surface of the light guide optical element 118a.

[0042] Figure 8 A folded optical waveguide 400 (hereinafter referred to as "waveguide" 400) with an image projector 112 mounted thereto and a user's eye are shown for reference. Waveguide 400 includes components similar to those of waveguide 300 (and waveguide 200), and therefore similar reference numerals are used where applicable.

[0043] like Figure 8 As shown, waveguide 400 includes a prism 302 disposed in a gap 119 between optical guide optical elements 118a and 118b (e.g., close to coupling element 210). For example, prism 302 may include material configured to correct or compensate for dispersion caused by the waveguide material to guide a light beam from optical guide optical element 118a to coupling element 210. Figure 7 Compared to the implementation method, in Figure 8In one embodiment, instead of using an output element 208, a prism 302 is used to guide a beam of light internally reflected within the light-guiding optical element 118a toward the input element 210. For this purpose, the prism 302 can be bonded or attached to the light-guiding optical elements 118a and 118b using a refractive index-matched adhesive or other material with a sufficiently high refractive index, so that the beam of light propagating through the light-guiding optical element 118a escapes from the TIR and passes through the prism 302. The prism 302 can also have a refractive index high enough to allow light to escape from the TIR. The prism 302 can include a material selected to correct or compensate for the dispersion of the waveguide and can include a block, wedge, or any other configuration comprising two or more materials or prisms. In one embodiment, using two prisms allows the light-guiding optical elements 118a and 118b to be parallel to each other rather than at an acute angle without using the output element 208, for example, as shown in the image. Figure 4 As shown.

[0044] In some embodiments, the gap 119 in the waveguide 400 can be used to mount additional components of the optical system 100, such as other electronic components, processors, etc., thereby enabling a more compact design. Furthermore, an image projector 112 can be mounted within the gap 119, and the aperture 202 can be positioned on the inner main surface of the light guide optical element 118a.

[0045] Figure 9 A folded optical waveguide 500 (hereinafter referred to as "waveguide" 500) with an image projector 112 mounted thereto and a user's eye are shown for reference. Waveguide 500 includes components similar to those of waveguide 200, and therefore similar reference numerals are used where applicable. Waveguide 500 shows several optional components or elements that can be implemented within the corresponding optical guide optics 118.

[0046] For example, waveguide 500 may include one or more homogenizers 212 within the light-guide optical element 118 along the optical path between the first set of facets 204 and the second set of facets 206. In some implementations, the homogenizers 212 may be located in the same region as the first set of facets 204 or the second set of facets 206 (e.g., not between them). Figure 9 As shown, for example, a homogenizer 212 may be disposed within each of the light-guiding optical elements 118a and 118b. In other embodiments, one of the light-guiding optical elements 118a or 118b may include a homogenizer, while the other light-guiding optical element may not include a homogenizer. In other embodiments, multiple homogenizers may be used in the same light-guiding optical element 118.

[0047] The homogenizer 212 can be any type of light homogenizer configured to provide improved illumination uniformity. For example, the homogenizer 212 can include a partially planar reflector, a partially transmissive surface, or a film (e.g., a partially reflective dielectric coating) added within either or both of the light guide optics 118 as a semi-reflective surface. The homogenizer 212 can effectively fill gaps in the illumination within the waveguide 200 by partially separating the light beam passing through the waveguide 500.

[0048] Waveguide 500 may also include material 404, material 406, or both to prevent light from traveling from the external environment through waveguide 200 and / or between light-guiding optical elements 118a and 118b. For example, material 404 and / or material 406 may be a polarizer or any optical film (e.g., waveplate, color filter, etc.).

[0049] Waveguide 500 may include an optical element 408 disposed between the output element 208 and the input element 210. The optical element 408 may include, for example, a polarizer, lens, prism, full-wave plate, half-wave plate, quarter-wave plate, color filter, or other optical element or any combination thereof, which may be used to adjust the nature of the beam, block or prevent a portion of the beam from passing through it, etc.

[0050] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It will be further understood that, when used in this specification, the terms “comprising,” “including,” and / or “containing” designate the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Furthermore, the terms “upper,” “upper,” “lower,” “below,” “over,” “below,” “left,” “right,” “front,” “rear,” etc., are intended to be understood in the context of the representations described and shown above, such that the wearable device may have such an orientation as relating to a frame or to various elements as shown in the accompanying drawings.

[0051] All methods or steps plus functional elements (if any) in the appended claims are intended to include corresponding structures, materials, actions, and equivalents for performing functions in combination with other claimed elements as specifically claimed. The description of the invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention as disclosed. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Various embodiments were chosen and described in order to best illustrate the principles and practical application of the invention and to enable others skilled in the art to understand the invention in order to obtain various embodiments with various modifications suitable for the particular purpose conceived.

[0052] Example

[0053] Example 1: An optical waveguide includes a first waveguide and a second waveguide. The first waveguide includes: a pair of parallel first main surfaces; an aperture disposed on one of the first main surfaces and configured to receive an input light beam; a first set of facets disposed between the first main surfaces along a first axis and configured to receive the input light beam and reflect the input light beam at least partially as a first light beam; and an output element configured to receive the first light beam and reflect the first light beam out of the first waveguide. The second waveguide includes: a pair of parallel second main surfaces, wherein at least one of the second main surfaces faces at least one of the first main surfaces; an input element configured to receive the first light beam and reflect the first light beam toward the second set of facets; and a second set of facets disposed between the second main surfaces along a second axis and configured to: receive the first light beam and reflect the first light beam at least partially as a second light beam; and couple the second light beam out of the second waveguide.

[0054] Example 2: The optical waveguide according to Example 1, wherein the first waveguide and the second waveguide are parallel to each other.

[0055] Example 3: The optical waveguide according to Example 1, wherein the first waveguide is configured to form an acute angle with the second waveguide.

[0056] Example 4: An optical waveguide according to any of the foregoing examples, wherein a gap is formed between the first waveguide and the second waveguide.

[0057] Example 5: The optical waveguide according to Example 4 further includes a material disposed within the gap and configured to prevent light from transmitting between the first waveguide and the second waveguide.

[0058] Example 6: The optical waveguide according to Example 4 further includes a prism disposed within the gap and configured to couple the first beam between the first waveguide and the second waveguide.

[0059] Example 7: The optical waveguide according to Example 6, wherein the prism is attached to the end portion of the first waveguide and the end portion of the second waveguide.

[0060] Example 8: The optical waveguide according to Example 4 further includes a polarizer, lens, prism, full-wave plate, half-wave plate or quarter-wave plate disposed within the gap.

[0061] Example 9: An optical waveguide according to any of the preceding examples, wherein the outgoing element includes a first mirror and the incoming element includes a second mirror.

[0062] Example 10: An optical waveguide according to any of the preceding examples, wherein: the coupling element is arranged at a first end portion of the first waveguide, and the coupling element is arranged at a second end portion of the second waveguide; and the first end portion and the second end portion are configured to be adjacent to each other.

[0063] Example 11: The optical waveguide according to any of the foregoing examples further includes a material disposed adjacent to one of the first main surfaces remote from the second waveguide and configured to prevent light from the external environment from entering the first waveguide.

[0064] Example 12: The optical waveguide according to Example 11, wherein the material comprises an opaque material.

[0065] Example 13: An optical waveguide according to any of the foregoing examples, wherein the waveguide is configured such that the user's line of sight passes sequentially through the second waveguide and the first waveguide.

[0066] Example 14: An optical waveguide according to any of the preceding examples, wherein the surface area of ​​at least one of the first main surfaces is greater than the surface area of ​​at least one of the second main surfaces.

[0067] Example 15: An apparatus comprising: a projector configured to generate an input beam; and an optical waveguide as described in any of the preceding examples.

Claims

1. An optical waveguide, comprising: A first waveguide, comprising: A pair of parallel primary surfaces; An aperture, wherein the aperture is disposed on one of the first main surfaces and configured to receive an input light beam; A first set of facets, disposed along a first axis between the first main surfaces and configured to receive the input beam and at least partially reflect the input beam as a first beam; and A coupling element configured to receive the first light beam and reflect it out of the first waveguide; and The second waveguide includes: A pair of parallel second main surfaces, wherein at least one of the second main surfaces faces at least one of the first main surfaces; Coupler element, the coupling element being configured to receive the first beam and reflect the first beam toward a second set of facets; and The second set of small planes, disposed along the second axis between the second main surfaces, is configured as follows: Receive the first beam and reflect the first beam at least partially into a second beam; and The second beam is coupled out of the second waveguide.

2. The optical waveguide according to claim 1, wherein, The first waveguide and the second waveguide are parallel to each other.

3. The optical waveguide according to claim 1, wherein, The first waveguide is configured to form an acute angle with the second waveguide.

4. The optical waveguide according to claim 1, wherein, A gap is formed between the first waveguide and the second waveguide.

5. The optical waveguide of claim 4, further comprising a material disposed within the gap and configured to prevent light transmission between the first waveguide and the second waveguide.

6. The optical waveguide of claim 4 further includes a prism disposed within the gap and configured to couple the first beam between the first waveguide and the second waveguide.

7. The optical waveguide according to claim 6, wherein, The prism is attached to the end portions of the first waveguide and the second waveguide.

8. The optical waveguide according to claim 4 further includes a polarizer, lens, prism, full-wave plate, half-wave plate or quarter-wave plate disposed close to the coupling element and the coupling element within the gap.

9. The optical waveguide according to claim 1, wherein, The outgoing element includes a first mirror, and the incoming element includes a second mirror.

10. The optical waveguide according to claim 1, wherein: The coupling-out element is disposed at a first end portion of the first waveguide, and the coupling-in element is disposed at a second end portion of the second waveguide; and The first end portion and the second end portion are configured to be adjacent to each other.

11. The optical waveguide of claim 1, further comprising a material disposed adjacent to one of the first main surfaces remote from the second waveguide and configured to prevent light from the external environment from entering the first waveguide.

12. The optical waveguide according to claim 11, wherein, The materials include opaque materials.

13. The optical waveguide according to claim 1, wherein, The waveguide is configured such that the user's line of sight passes sequentially through the second waveguide and the first waveguide.

14. The optical waveguide according to claim 1, wherein, The surface area of ​​at least one of the first main surfaces is greater than the surface area of ​​at least one of the second main surfaces.

15. An apparatus comprising: A projector configured to generate an input beam; as well as The optical waveguide according to claim 1.

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