Enhanced pupil replication using folded gratings for eyepieces in near-eye displays

Abstract

[0003] In one embodiment, a waveguide combiner is provided that includes a first surface, a second surface, an in-coupler located on the first surface configured to receive a plurality of input beams and diffract a first subset of the beams and a second subset of the beams into two opposing directions in K-space by total internal reflection (TIR), a first folded grating located on the first surface configured to receive the first subset of the beams from the in-coupler at a first region and diffract the first subset of the beams to a second region, a second folded grating located on the first surface configured to receive the second subset of the beams from the in-coupler at a third region and diffract the second subset of the beams to the second region, and a first out-coupler located on the first surface.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE Embodiments of the present disclosure relate generally to near-eye display systems, and more particularly to near-eye display systems with increased exit pupil density and increased image sharpness and uniformity. [Background technology]

[0002] Virtual reality (VR) is generally considered to be a computer-generated simulated environment in which a user has an apparent physical presence. The virtual reality experience may be generated in 3D and viewed through a head-mounted display (HMD), such as glasses or other wearable display device, with near-eye display panels as lenses for displaying the virtual reality environment in place of the real environment.

[0003] Augmented reality (AR), on the other hand, allows for an experience in which a user can still see the surrounding environment through the display lenses of glasses or other HMD devices to capture the surrounding environment, and can also see images of virtual objects that are generated for display and appear as part of that environment. AR can include any type of input, such as audio and tactile input, as well as virtual images, graphics, and video, that enhances or augments the environment experienced by the user. As an emerging technology, there are many challenges and design constraints related to augmented reality.

[0004] For waveguide combiners in near-eye display systems, it is desirable to increase the density of the exit pupil relative to the user's eyebox. A conventional way to increase pupil density involves reducing the thickness of the waveguide combiner. This reduction in thickness leads to an increase in incoupled light that re-encounters the incoupler, which causes a loss in image sharpness and quality and an increase in non-uniformity. If the substrate is thickened, a lower pupil density can create additional high-frequency non-uniformity due to the sparsely replicated pupil reaching the user's eyebox.

[0005] Therefore, what is needed in the art is an improved waveguide combiner. Summary of the Invention

[0006] In one embodiment, a waveguide combiner is provided that includes a first surface, a second surface, an in-coupler located on the first surface configured to receive a plurality of input beams and diffract a first subset of the beams and a second subset of the beams into total internal reflection (TIR) ​​in two opposite directions in K-space, a first folded grating located on the first surface configured to receive the first subset of beams from the in-coupler in a first region in K-space and diffract the first subset of beams in TIR to a second region in K-space, a second folded grating located on the first surface configured to receive the second subset of beams from the in-coupler in a third region in K-space and diffract the second subset of beams in TIR to the second region in K-space, and a first out-coupler located on the first surface.

[0007] In another embodiment, a waveguide combiner is provided that includes a first surface, a second surface, an in-coupler located on the first surface configured to receive multiple input beams and diffract the multiple input beams into total internal reflection (TIR), a first duplicator grating located on the first surface proximate to and below the in-coupler configured to receive the multiple input beams from the in-coupler in a first region in K space and diffract the multiple input beams in TIR to a second region in K space, a second duplicator grating located on the first surface proximate to and below the first duplicator grating, a first out-coupler located on the first surface proximate to or below the second duplicator grating, and a second out-coupler located on the second surface.

[0008] In yet another embodiment, a waveguide combiner is provided, the waveguide combiner including a first surface, a second surface, an in-coupler located on the first surface configured to receive a plurality of input beams and diffract a first subset of the beams and a second subset of the beams into total-internal-reflection (TIR) ​​in two opposite directions in K-space, and the in-coupler configured to receive the first subset of beams from the in-coupler in a first region in K-space and diffract the first subset of beams in TIR into a second region in K-space. a first folding grating located on the first surface, and a second folding grating located on the first surface configured to receive a second subset of beams from the incoupler in a third region in K-space and diffract the second subset of beams in TIR to a second region in K-space; and a second folding grating located on the first surface, configured to receive the first subset of beams from the first folding grating and the second subset of beams from the second folding grating in the second region in K-space and diffract a first portion of the first subset of beams. and a first portion of the second subset of beams into a fourth region in K space, a second portion of the first subset of beams and a second portion of the second subset of beams into a fifth region in K space, a third portion of the first subset of beams and a third portion of the second subset of beams from a sixth region, and a fourth portion of the first subset of beams and a fourth portion of the second subset of beams from a seventh region in K space. an out-coupler for receiving, in a second region in K-space, a first portion of the first subset of beams and a first portion of the second subset of beams from the first folded grating and the second folded grating, diffracting a third portion of the first subset of beams and a third portion of the second subset of beams to a sixth region, diffracting a fourth portion of the first subset of beams and a fourth portion of the second subset of beams to a seventh region in K-space, and diffracting the first portion of the first subset of beams from the fourth region;and an expander grating located on the second surface configured to outcouple a first portion of the second subset of beams and to outcouple a second portion of the first subset of beams and a second portion of the second subset of beams from a fifth region in K-space.

[0009] So that the above-recited features of the present disclosure may be understood in detail, a more particular description of the present disclosure briefly summarized above can be made by reference to embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings illustrate only exemplary embodiments and, therefore, should not be considered as limiting the scope of the present disclosure, as other equally effective embodiments may be recognized. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view of a near-eye display system according to one or more embodiments of the present disclosure. [Figure 2] 2 is a cross-sectional view of the near-eye display system of FIG. 1 in accordance with one or more embodiments of the present disclosure. [Figure 3A] FIG. 2 is a top view of a first surface of a first configuration of a waveguide combiner of a near-eye display system according to an embodiment of the present disclosure. [Figure 3B] FIG. 10 is a bottom view of a second surface of a first configuration of a waveguide combiner of a near-eye display system according to an embodiment of the present disclosure. [Figure 3C] FIG. 2 is a K-space diagram of a first configuration of a waveguide combiner according to an embodiment of the present disclosure. [Figure 3D] 1A-1C illustrate a comparison of pupil replication graphs for a first configuration and a conventional grating vector architecture, according to an embodiment of the present disclosure. [Figure 4A] FIG. 10 is a top view of a first surface of a second configuration of a waveguide combiner of a near-eye display system according to an embodiment of the present disclosure. [Figure 4B]FIG. 10 is a bottom view of a second surface of a second configuration of a waveguide combiner of a near-eye display system according to an embodiment of the present disclosure. [Figure 4C] FIG. 10 illustrates a K-space diagram of a second configuration of a waveguide combiner in accordance with an embodiment of the present disclosure. [Figure 5A] FIG. 10 is a top view of a first surface of a third configuration of a waveguide combiner of a near-eye display system according to an embodiment of the present disclosure. [Figure 5B] FIG. 10 is a bottom view of a second surface of a third configuration of a waveguide combiner of a near-eye display system according to an embodiment of the present disclosure. [Figure 5C] FIG. 10 illustrates a K-space diagram of a third configuration in a fourth configuration according to an embodiment of the present disclosure. [Figure 5D] FIG. 10 illustrates a comparison of pupil replication graphs for the third configuration and a conventional grating vector architecture, according to an embodiment of the present disclosure. [Figure 6A] FIG. 10 is a top view of a first surface of a fourth configuration of a waveguide combiner of a near-eye display system according to an embodiment of the present disclosure. [Figure 6B] FIG. 10 is a bottom view of the second surface of a fourth configuration of a waveguide combiner of a near-eye display system according to an embodiment of the present disclosure. [Figure 6C] FIG. 10 illustrates a K-space diagram of a fourth configuration of a waveguide combiner in accordance with an embodiment of the present disclosure. [Figure 6D] FIG. 10 illustrates a comparison of pupil replication graphs for a fourth configuration and a conventional grating vector architecture, according to an embodiment of the present disclosure. [Figure 7A] FIG. 10 is a top view of a first surface of a fifth configuration of a waveguide combiner of a near-eye display system according to an embodiment of the present disclosure. [Figure 7B] FIG. 10 is a bottom view of the second surface of a fifth configuration of a waveguide combiner of a near-eye display system according to an embodiment of the present disclosure. [Figure 7C] FIG. 10 illustrates a K-space diagram of a fifth configuration of a waveguide combiner in accordance with an embodiment of the present disclosure. [Figure 8A]FIG. 10 is a top view of a first surface of a sixth configuration of a waveguide combiner of a near-eye display system according to an embodiment of the present disclosure. [Figure 8B] FIG. 10 is a bottom view of the second surface of a sixth configuration of a waveguide combiner of a near-eye display system according to an embodiment of the present disclosure. [Figure 8C] FIG. 10 illustrates a K-space diagram of a sixth configuration of a waveguide combiner in accordance with an embodiment of the present disclosure. [Figure 8D] FIG. 10 illustrates a comparison of pupil replication graphs for the sixth configuration and a conventional grating vector architecture, according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] For ease of understanding, wherever possible, like reference numerals have been used to refer to like elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

[0012] The embodiments described herein generally relate to near-eye display systems. More particularly, the embodiments described herein relate to near-eye display systems with increased exit pupil density, image sharpness, and image uniformity. The diffractive waveguide combiner layer is designed to increase the exit pupil density without substantially reducing the thickness of the waveguide combiner layer. Because the thickness of the waveguide combiner layer is not substantially reduced, in-coupler rebounce is avoided. However, because the exit pupil density is still high, high-frequency non-uniformities in the projected image are further avoided, particularly through the use of lasers.

[0013] FIG. 1 shows a perspective view of a near-eye display system 100 according to one or more embodiments of the present disclosure. The near-eye display system 100 may present media to a user. Examples of media presented by the near-eye display system 100 may include one or more images, videos, and / or audio. In one embodiment that may be combined with other embodiments, audio may be presented via an external device (e.g., speakers and / or headphones) that receives audio information from the near-eye display system 100, the console, or both, and presents audio data based on the audio information. The near-eye display system 100 is generally configured to operate as a virtual reality display. In one embodiment that may be combined with other embodiments, the near-eye display system 100 may operate as an augmented reality (AR) display.

[0014] Near-eye display system 100 may include a frame 110 and a display 120. Frame 110 may be coupled to one or more optical elements. Display 120 may be configured for a user to view content presented by near-eye display system 100. In one embodiment, which may be combined with other embodiments, display 120 may include a waveguide combiner for directing light from one or more images to the user's eye.

[0015] 2 shows a cross-sectional view of the near-eye display system 100 of FIG. 1 in accordance with one or more embodiments of the present disclosure. The near-eye display system 100 may include at least one waveguide combiner 210 having a first surface 202 facing a second surface 204. The waveguide combiner 210 is configured to direct image light, e.g., display light, to an eyebox 220 that defines an eyebox plane and then to a user's eye 230. The waveguide combiner 210 may include one or more materials with one or more refractive indices. In one embodiment, which may be combined with other embodiments, the near-eye display system 100 may include one or more optical elements between the waveguide combiner 210 and the user's eye 230.

[0016] Embodiments of the present disclosure discuss diffractive waveguide combiner layers with novel grating architectures that utilize additional gratings. For example, double-folded gratings with unique grating vectors or double duplicator gratings with unique grating vectors may be utilized to enhance pupil duplication prior to pupil widening and outcoupling in subsequent grating regions such as outcouplers.

[0017] 3A shows a top view of a first surface 202 of a first configuration 301 of a waveguide combiner 210 of a near-eye display system 100 according to an embodiment. FIG. 3B shows a bottom view of a second surface 204 of a first configuration 301 of a waveguide combiner 210 of a near-eye display system 100 according to an embodiment. The second surface 204 faces the first surface 202.

[0018] The first surface 202 of the first configuration 301 includes an in-coupler 315, a first folded grating 335A, a second folded grating 335B, and a first out-coupler 325A disposed on or above the first surface 202. The first folded grating 335A is located proximate to the in-coupler 315. The second folded grating 335B is located proximate to the in-coupler 315 opposite the first folded grating 335A. The first out-coupler 325A is located proximate to the in-coupler 315, the first folded grating 335A, and the second folded grating 335B. In one example, the first out-coupler 325A is positioned above the first folded grating 335A and the second folded grating 335B. In another example, the first out-coupler 325A is positioned below the first folded grating 335A and the second folded grating 335B.

[0019] The second surface 204 of the first configuration 301 includes a second out-coupler 325B disposed on or above the second surface 204. In one embodiment that may be combined with other embodiments described herein, the second surface 204 of the first configuration 301 includes the second out-coupler 325B, a third folded grating 375A, and a fourth folded grating 375B. The third folded grating 375A is adjacent to the fourth folded grating 375B. In one example of an embodiment including the third folded grating 375A and the fourth folded grating 375B, the second out-coupler 325B is positioned above the third folded grating 375A and the fourth folded grating 375B. In another example embodiment including a third folded grating 375A and a fourth folded grating 375B, the second out-coupler 325B is positioned below the third folded grating 375A and the fourth folded grating 375B. The in-coupler 315 may have a circular or oval shape. The first out-coupler 325A and the second out-coupler 325B may have a square or rectangular shape. The first folded grating 335A and the second folded grating 335B may have a trapezoidal shape.

[0020] 3C shows a K-space diagram 310 of the first configuration 301 of the waveguide combiner 210. The K-space diagram 310 depicts the path of a virtual FOV generated from the microdisplay of the near-eye display system 100. The path of the virtual FOV is the intended image path using a hexagonal lattice structure in the K-space domain. In the K-space diagram, the inner circle represents free space, the outer circle represents the substrate, and the space between the outer diameters of the circles represents the TIR. In the optical device, the virtual FOV (light) propagates in the TIR between the gratings. As shown in K-space diagram 310, light from a light source, e.g., a virtual FOV, is incoupled by incoupler 315 and diffracted into beams along path 321A to a first region 320L corresponding to the direction of light that will propagate into the first folded grating 335A, and path 321B to a second region 320R corresponding to the direction of light that will propagate into the second folded grating 335B. L and R represent "left" and "right," respectively. The beam entering the first folded grating 335A is diffracted along path 331A to regions 330R corresponding to the direction of light that will propagate into the first outcoupler 325A and the second outcoupler 325B. The beam incident on the second folded grating 335B is diffracted along path 331B to region 330R corresponding to the direction of light that will propagate into the first out-coupler 325A and the second out-coupler 325B. The beam incident on the first out-coupler 325A is diffracted by the first out-coupler 325A along path 341A to region 340R corresponding to the direction of light that will propagate into the second out-coupler 325B. The second out-coupler 325B then outcouples the light along path 351B to the user eyebox 308. The beam incident on the second out-coupler 325B is diffracted by the second out-coupler 325B along path 341B to region 340L corresponding to the direction of light that will propagate into the first out-coupler 325A. The first outcoupler 325A then outcouples the light along path 351A to the user eyebox 308.

[0021] The locations of first region 320L and second region 320R must be different from the locations of regions 340L and 340R, respectively, to ensure that the new grid of diffracted beam regions corresponding to regions 340L and 340R does not align with the current grid of diffracted beam regions corresponding to first region 320L and second region 320R. Additionally, the placement of first folded grating 335A and second folded grating 335B mitigates the entity of the new grid of diffracted beam regions creating an entirely new set of exit pupil regions that can reach the user's eyebox and creating "ghost paths" that can result in secondary, shifted copies of the intended virtual content in the user's FOV. In some embodiments, the positions of the first and second regions 320L and 320R, and the positions of regions 340L and 340R, entail shifting the positions of regions 340L and 340R in K-space such that the shifted region positions are sufficiently far away from the current K-space region positions 320L and 320R (e.g., at least about 0.02k0 away, where k0 is 2*pi / lambda and lambda is the wavelength of light).

[0022] FIG. 3D shows a comparison of pupil replication graphs for the first configuration 301 and the conventional grating vector architecture 302. The pupil replication graph represents an FOV angle of approximately (0 degrees, 0 degrees). As shown in FIG. 3D, each point on the pupil replication graph represents an exit pupil. The eyebox 380 of the waveguide combiner 210 includes a greater number of exit pupils than the eyebox 382 of the conventional grating vector architecture 302. The eyebox 380 receiving a greater number of exit pupils results in an increased exit pupil density for a waveguide combiner having the same thickness. FIG. 3D allows a direct comparison of the enhanced pupil replication and increased exit pupil density for the waveguide combiner 210. The increased pupil density for the waveguide combiner 210 is achieved with a substrate having the same thickness as the waveguide combiner for the conventional grating vector architecture 302. For example, the exit pupil density is at least about five times higher than the waveguide combiner for the conventional grating vector architecture 302. Therefore, the substrate thickness does not need to be reduced or may even be increased while maintaining a high exit pupil density, which mitigates the deleterious image effects of incoupler rebounce while also suppressing high frequency non-uniformities.

[0023] 4A shows a top view of a first surface 202 of a second configuration 401 of a waveguide combiner 210 of a near-eye display system 100 in accordance with an embodiment. FIG. 4B shows a bottom view of a second surface 204 of a waveguide combiner 210 of a near-eye display system 100 in accordance with an embodiment. The second surface 204 faces the first surface 202.

[0024] The first surface 202 of the waveguide combiner 210 includes an in-coupler 415, a first two-dimensional out-coupler 425A, a first folded grating 435A, and a second folded grating 435B disposed on or above the first surface 202. Two-dimensional gratings, such as the first two-dimensional out-coupler 425A, contain periodicity in two directions, resulting in diffraction orders in the two directions. The first folded grating 435A is located proximate to the in-coupler 415. The second folded grating 435B is located proximate to the in-coupler 415 opposite the first folded grating 435A. The first two-dimensional out-coupler 425A is located proximate to the in-coupler 415, the first folded grating 435A, and the second folded grating 435B. In one example, the first two-dimensional out-coupler 425A is positioned above the first folded grating 435A and the second folded grating 435B. In another example, the first two-dimensional out-coupler 425A is positioned below the first folded grating 435A and the second folded grating 435B.

[0025] In one embodiment that may be combined with other embodiments described herein, the second surface 204 of the waveguide combiner 210 includes a third folded grating 475A, a fourth folded grating 475B, and a second outcoupler 425B. The second outcoupler 425B may be a one-dimensional or two-dimensional outcoupler. The third folded grating 475A is adjacent to the fourth folded grating 475B. In one example of an embodiment including the third folded grating 475A and the fourth folded grating 475B, the second outcoupler 425B is positioned above the third folded grating 475A and the fourth folded grating 475B. In another example of an embodiment including a third folded grating 475A and a fourth folded grating 475B, the second out-coupler 425B is positioned below the third folded grating 475A and the fourth folded grating 475B. The in-coupler 415 may have a circular or oval shape. The first two-dimensional out-coupler 425A may have a rectangular or square shape. The first folded grating 435A and the second folded grating 435B may have a trapezoidal shape.

[0026] FIG. 4C shows a K-space diagram 410 of the second configuration 401 of the waveguide combiner 210. FIG. 4C is similar to FIG. 3C except that the out-coupler 425A is a two-dimensional out-coupler. The K-space diagram 410 depicts the path of a virtual FOV generated from the microdisplay of the near-eye display system 100. The path of the virtual FOV is the intended image path using a hexagonal lattice structure in the K-space domain. As shown in the K-space diagram 410, light from a light source, e.g., the virtual FOV, is incoupled by the in-coupler 415 and diffracted into beams along path 421A to a first region 420L, which corresponds to the direction of light that will propagate into the first folded grating 435A, and path 421B to a second region 420R, which corresponds to the direction of light that will propagate into the second folded grating 435B. L and R represent "left" and "right," respectively. A beam incident on the first folded grating 435A is diffracted along path 431A to region 430 corresponding to the direction of the light that will propagate into the first 2D outcoupler 425A. A beam incident on the second folded grating 435B is diffracted along path 431B to region 430 corresponding to the direction of the light that will propagate into the first 2D outcoupler 425A. A beam incident on the first 2D outcoupler 425A is diffracted in two directions along path 441A to region 440R and along path 441B to region 440L. The first 2D outcoupler 425A then outcouples light from region 440L along path 451A and from region 440R along path 451B to the user eyebox 408.

[0027] The locations of the first region 420L and the second region 420R must be different from the locations of the regions 440L and 440R, respectively, to ensure that the new grid of diffracted beam regions corresponding to the regions 440L and 440R does not align with the current grid of diffracted beam regions corresponding to the first region 420L and the second region 420R. Additionally, the placement of the first folded grating 435A and the second folded grating 435B mitigates the appearance of the new grid of diffracted beam regions creating an entirely new set of exit pupil regions that can reach the user's eyebox and creating "ghost paths" that can result in secondary, shifted copies of the intended virtual content in the user's FOV. In some embodiments, the positions of the first region 420L and the second region 420R, and the positions of the regions 440L and 440R, entail shifting the positions of the regions 440L and 440R in K-space such that the shifted region positions are sufficiently far away (e.g., at least about 0.02kO away) from the current K-space region positions 420L and 420R.

[0028] 5A shows a top view of a first surface 202 of a waveguide combiner 210 of a third configuration 501 of a near-eye display system 100 according to an embodiment. FIG. 5B shows a bottom view of a second surface 204 of a waveguide combiner 210 of a near-eye display system 100 according to an embodiment. The second surface 204 faces the first surface 202.

[0029] The first surface 202 of the waveguide combiner 210 includes an in-coupler 515, a first out-coupler 525A, a first folded grating 535A, and a second folded grating 535B. The first folded grating 535A is located proximate to the in-coupler 515. The second folded grating 535B is located proximate to the in-coupler 515 corresponding to the first folded grating 535A. The first out-coupler 525A is located proximate to the in-coupler 515, the first folded grating 535A, and the second folded grating 535B. In one example, the first out-coupler 525A is positioned above the first folded grating 435A and the second folded grating 435B. In another example, the first out-coupler 525A is positioned below the first folded grating 435A and the second folded grating 435B.

[0030] The second surface 204 of the waveguide combiner 210 includes a two-dimensional expander grating 525B. In one embodiment that may be combined with other embodiments described herein, the second surface 204 of the waveguide combiner 210 includes the two-dimensional expander grating 525B, a third folded grating 575A, and a fourth folded grating 575B. The third folded grating 575A is adjacent to the fourth folded grating 575B. In one example of an embodiment including the third folded grating 575A and the fourth folded grating 575B, the two-dimensional expander grating 525B is positioned above the third folded grating 575A and the fourth folded grating 575B. In another example of an embodiment including a third folded grating 575A and a fourth folded grating 575B, the two-dimensional expander grating 525B is positioned below the third folded grating 575A and the fourth folded grating 575B. The in-coupler 515 may have a circular or oval shape. The first out-coupler 525A and the two-dimensional expander grating 525B may have a square or rectangular shape. The first folded grating 535A and the second folded grating 535B may have a trapezoidal shape.

[0031] FIG. 5C shows a K-space diagram 510 of the third configuration 501 of the waveguide combiner 210. The K-space diagram 510 depicts the path of a virtual FOV generated from the microdisplay of the near-eye display system 100. The path of the virtual FOV is the intended image path using a rectangular lattice structure in the K-space domain. As shown in the K-space diagram 510, light from a light source, e.g., a virtual FOV, is incoupled by the incoupler 515 and diffracted into beams along path 521A to a first region 520L, which corresponds to the direction of light that will propagate into the first folded grating 535A, and path 521B to a second region 520R, which corresponds to the direction of light that will propagate into the second folded grating 535B. L and R represent "left" and "right," respectively. A beam incident on the first folded grating 535A is diffracted along path 531A to region 530 corresponding to the direction of light that will propagate into the first out-coupler 525A and two-dimensional expander grating 525B. A beam incident on the second folded grating 535B is diffracted along path 531B to region 530 corresponding to the direction of light that will propagate into the first out-coupler 525A and two-dimensional expander grating 525B. A beam incident on the first out-coupler 525A is diffracted by the first out-coupler 525A along path 551A to region 540L corresponding to the direction of light that will propagate into the two-dimensional expander grating 525B, and along path 551B to region 540R corresponding to the direction of light that will propagate into the two-dimensional expander grating 525B. Two-dimensional expander grating 525B then outcouples the light along paths 581A and 581B to user eyebox 508. The beam incident on two-dimensional expander grating 525B is diffracted by the two-dimensional expander grating along path 541A to region 560L corresponding to the direction of the light that is to propagate into first outcoupler 525A, and along path 541B to region 560R corresponding to the direction of the light that is to propagate into first outcoupler 525A.The first outcoupler 525A then outcouples the light along paths 571A and 571B to the user eyebox 508.

[0032] The positions of first region 520L and second region 520R must be different from the positions of regions 560L and 560R, respectively, to ensure that the new grid of diffracted beam regions corresponding to regions 560L and 560R does not align with the current grid of diffracted beam regions corresponding to first region 520L and second region 520R. Additionally, the placement of first folded grating 535A and second folded grating 535B mitigates the appearance of a new grid of diffracted beam regions that creates an entirely new set of exit pupil regions that can reach the user's eyebox and creates "ghost paths" that can result in secondary, shifted copies of the intended virtual content in the user's FOV. In some embodiments, the positions of the first and second regions 520L and 520R, and the positions of regions 560L and 560R, entail shifting the positions of regions 560L and 560R in K-space such that the shifted region positions are sufficiently far away (e.g., at least about 0.02k0 away) from the current K-space region positions 520L and 520R.

[0033] FIG. 5D shows a comparison of pupil replication graphs for the third configuration 501 and the conventional grating vector architecture 502. The pupil replication graph represents an FOV angle of approximately (0 degrees, 0 degrees). As shown in FIG. 5D, each point on the pupil replication graph represents an exit pupil. The eyebox 580 of the waveguide combiner 210 includes a greater number of exit pupils than the eyebox 582 of the conventional grating vector architecture 502. The eyebox 580 receiving a greater number of exit pupils results in an increased exit pupil density for a waveguide combiner having the same thickness. FIG. 5D allows a direct comparison of the enhanced pupil replication and increased exit pupil density for the waveguide combiner 210. The increased pupil density for the waveguide combiner 210 is achieved with a substrate having the same thickness as the waveguide combiner for the conventional grating vector architecture 502. For example, the exit pupil density is at least about five times higher than the waveguide combiner for the conventional grating vector architecture 502. Thus, the substrate thickness need not be reduced or may even be increased while maintaining a high exit pupil density, which mitigates the deleterious image effects of incoupler rebounce while also suppressing high frequency non-uniformities.

[0034] 6A shows a top view of a first surface 202 of a fourth configuration 601 of a waveguide combiner 210 of a near-eye display system 100 in accordance with an embodiment. FIG. 6B shows a bottom view of a second surface 204 of a waveguide combiner 210 of a near-eye display system 100 in accordance with an embodiment. The second surface 204 faces the first surface 202.

[0035] The first surface 202 of the waveguide combiner 210 includes an in-coupler 615, a first duplicator grating 635A, a second duplicator grating 635B, and a first out-coupler 625A disposed on or above the first surface 202. The first duplicator grating 635A is located adjacent to or below the in-coupler 615 from a top view, as shown in FIG. 6A. The second duplicator grating 635B is located adjacent to or below the first duplicator grating 635A from a top view, as shown in FIG. 6A, such that the first duplicator grating 635A and the second duplicator grating 635B are aligned. In one example, the first out-coupler 625A is located adjacent to or below the second duplicator grating 635B from a top view, as shown in Figure 6A. In another example, the first out-coupler 625A is positioned above the in-coupler 615.

[0036] The second surface 204 of the waveguide combiner 210 includes a second out-coupler 625B disposed on or above the second surface 204. In one embodiment that may be combined with other embodiments described herein, the second surface 204 of the waveguide combiner 210 includes the second out-coupler 625B, a third duplicator grating 675A, and a fourth duplicator grating 675B. The fourth duplicator grating 675B is adjacent to or below the third duplicator grating 675A. In one example of an embodiment including the third duplicator grating 675A and the fourth duplicator grating 675B, the second out-coupler 625B is positioned above the third duplicator grating 675A. In another example of an embodiment including a third duplicator grating 675A and a fourth duplicator grating 675B, the second out-coupler 625B is positioned below the fourth duplicator grating 675B. The in-coupler 615 may have a circular or oval shape. The first out-coupler 625A and the second out-coupler 625B may have a square or rectangular shape. The first duplicator grating 635A and the second duplicator grating 635B may have a square or rectangular shape.

[0037] 6C shows a K-space diagram of the fourth configuration 601 of the waveguide combiner 210. The K-space diagram depicts the path of a virtual FOV generated from the microdisplay of the near-eye display system 100. The path of the virtual FOV is the intended image path using a hexagonal lattice structure in the K-space domain. As shown in the K-space diagram, light from a light source, e.g., the virtual FOV, is incoupled by the incoupler 615 and diffracted as a beam along path 621 to a first region 620. The beam incident on the first duplicator grating 635A is diffracted along path 631A to a region 630L corresponding to the direction of the light that will propagate into the first duplicator grating 635A, where it re-encounters the first duplicator grating 635A and is diffracted back to the first region 620. The beam diffracted back into the first region 620 encounters the second duplicator grating 635B and is diffracted along path 631B to region 630R corresponding to the direction of light that will propagate into the second duplicator grating 635B, where it is diffracted back into the first region 620. L and R represent "left" and "right," respectively. The beam diffracted back into the first region 620 by the second duplicator grating 635B, which enters the first out-coupler 625A, is diffracted by the first out-coupler 625A along path 641A to region 640R corresponding to the direction of light that will propagate into the second out-coupler 625B. The second out-coupler 625B then outcouples the light along path 651B to the user eyebox 608. The beam incident on second out-coupler 625B and diffracted back into first region 620 by second replicator grating 635B is diffracted by second out-coupler 625B along path 641B to region 640L corresponding to the direction of the light that was to propagate into first out-coupler 625A. First out-coupler 625A then outcouples the light along path 651A to user eyebox 608.

[0038] The locations of regions 630L and 630R must be different from the locations of regions 640L and 640R, respectively, to ensure that the new grid of diffracted beam regions corresponding to regions 640L and 640R does not align with the current grid of diffracted beam regions corresponding to regions 630L and 630R. Additionally, the placement of first duplicator grating 635A and second duplicator grating 635B creates an entirely new set of exit pupil regions that can reach the user's eyebox, and mitigates the appearance of diffracted beam regions that create "ghost paths" that can result in secondary, shifted copies of the intended virtual content in the user's FOV. In some embodiments, the positions of regions 630L and 630R, and the positions of regions 640L and 640R, entail shifting the positions of regions 640L and 640R in K-space such that the shifted region positions are sufficiently far away (e.g., at least about 0.02k0 away) from the current K-space region positions 630L and 630R.

[0039] FIG. 6D shows a comparison of pupil replication graphs for the fourth configuration 601 and the conventional grating vector architecture 602. The pupil replication graph represents an FOV angle of approximately (0 degrees, 0 degrees). As shown in FIG. 6D, each point on the pupil replication graph represents an exit pupil. The eyebox 680 of the waveguide combiner 210 includes a greater number of exit pupils than the eyebox 682 of the conventional grating vector architecture 602. The eyebox 680 receiving a greater number of exit pupils results in an increased exit pupil density for a waveguide combiner having the same thickness. FIG. 6D allows a direct comparison of the enhanced pupil replication and increased exit pupil density for the waveguide combiner 210. The increased pupil density for the waveguide combiner 210 is achieved with a substrate having the same thickness as the waveguide combiner for the conventional grating vector architecture 602. For example, the exit pupil density is at least about five times higher than the waveguide combiner for the conventional grating vector architecture 602. Thus, the substrate thickness need not be reduced or may even be increased while maintaining a high exit pupil density, which mitigates the deleterious image effects of incoupler rebounce while also suppressing high frequency non-uniformities.

[0040] 7A shows a top view of a first surface 202 of a fifth configuration 701 of a waveguide combiner 210 of a near-eye display system 100 in accordance with an embodiment. FIG. 7B shows a bottom view of a fifth configuration 701 of a near-eye display system 100 and a second surface 204 of a waveguide combiner 210. The second surface 204 faces the first surface 202.

[0041] The first surface 202 of the waveguide combiner 210 includes an in-coupler 715, a first two-dimensional out-coupler 725A, a first replicator grating 735A, and a second replicator grating 735B disposed on or above the first surface 202. Two-dimensional gratings such as the first two-dimensional out-coupler 725A incorporate periodicity in two directions, resulting in diffraction orders in two directions. The first replicator grating 735A is located adjacent to or below the in-coupler 715 from a top view, as shown in FIG. 7A . The second duplicator grating 735B is located adjacent to or below the first duplicator grating 735A from a top view, as shown in Figure 7A, so that the first duplicator grating 735A and the second duplicator grating 735B are aligned. In one example, the first two-dimensional out-coupler 725A is located adjacent to or below the second duplicator grating 735B from a top view, as shown in Figure 7A. In another example, the first two-dimensional out-coupler 725A is positioned above the in-coupler 715.

[0042] In one embodiment that may be combined with other embodiments described herein, the second surface 204 of the waveguide combiner 210 includes a third replicator grating 775A, a fourth replicator grating 775B, and a second outcoupler 725B. The second outcoupler 725B may be a one-dimensional or two-dimensional outcoupler. The fourth replicator grating 775B is adjacent to or below the third replicator grating 775A. In one example of an embodiment that includes a third replicator grating 775A and a fourth replicator grating 775B, the second outcoupler 725B is positioned above the third replicator grating 775A. In another example of an embodiment including a third duplicator grating 775A and a fourth duplicator grating 775B, the second out-coupler 725B is positioned below the fourth duplicator grating 775B. The in-coupler 715 may have a circular or oval shape. The first two-dimensional out-coupler 725A may have a square or rectangular shape. The first folded grating 735A and the second folded grating 735B may have a trapezoidal shape.

[0043] Figure 7C shows a K-space diagram 710 of the fifth configuration 701 of the waveguide combiner 210. Figure 7C is similar to Figure 6C except that outcoupler 725A is a two-dimensional outcoupler. As shown in K-space diagram 710, light from a light source, e.g., a virtual FOV, is incoupled by incoupler 715 and diffracted as a beam along path 721 to a first region 720. The beam incident on the first replicator grating 735A is diffracted along path 731A to a region 730L corresponding to the direction of the light that will propagate into the first replicator grating 735A, where it re-encounters the first replicator grating 735A and is diffracted back into the first region 720. The beam diffracted back to the first region 720 by the first duplicator grating 735A encounters the second duplicator grating 735B and is diffracted along path 731B to region 730R, which corresponds to the direction of the light that will propagate into the second duplicator grating 735B, where the beam is diffracted back to the first region 720. L and R represent "left" and "right," respectively. The beam diffracted back to the first region 720 by the second duplicator grating 735B that enters the first two-dimensional outcoupler 725A is diffracted by the first two-dimensional outcoupler 725A along paths 741A and 741B to regions 740R and 740L, respectively. The first two-dimensional outcoupler 725A then outcouples the light along paths 751A and 751B to the user eyebox 708.

[0044] The locations of regions 730L and 730R must be different from the locations of regions 740L and 740R, respectively, to ensure that the new grid of diffracted beam regions corresponding to regions 740L and 740R does not align with the current grid of diffracted beam regions corresponding to regions 730L and 730R. Additionally, the placement of first duplicator grating 735A and second duplicator grating 735B creates an entirely new set of exit pupil regions that can reach the user's eyebox, and reduces the occurrence of diffracted beam regions that create "ghost paths" that can result in secondary, shifted copies of the intended virtual content in the user's FOV. In some embodiments, the positions of regions 730L and 730R, and the positions of regions 740L and 740R, entail shifting the positions of regions 740L and 740R in K-space such that the shifted region positions are sufficiently far away (e.g., at least about 0.02k0 away) from the current K-space region positions 730L and 730R.

[0045] 8A shows a top view of a first surface 202 of a waveguide combiner 801 of a near-eye display system 100 according to an embodiment. FIG. 8B shows a bottom view of a second surface 204 of a waveguide combiner 801 of a near-eye display system 100 according to an embodiment. The second surface 204 faces the first surface 202.

[0046] The first surface 202 of the waveguide combiner 801 includes an in-coupler 815, a first out-coupler 825A, a first duplicator grating 835A, and a second duplicator grating 835B. The first duplicator grating 835A is located adjacent to or below the in-coupler 815 from a top view, as shown in FIG. 8A. The second duplicator grating 835B is located adjacent to or below the first duplicator grating 835A from a top view, as shown in FIG. 8A, such that the first duplicator grating 835A and the second duplicator grating 835B are aligned. In one example, the first out-coupler 825A is located adjacent to or below the second duplicator grating 835B from a top view, as shown in Figure 8A. In another example, the first out-coupler 825A is positioned above the in-coupler 815.

[0047] The second surface 204 of the waveguide combiner 801 includes a two-dimensional expander grating 845A. In one embodiment, which may be combined with other embodiments described herein, the second surface 204 of the waveguide combiner 801 includes a two-dimensional expander grating 845A, a third duplicator grating 875A, and a fourth duplicator grating 875B. The fourth duplicator grating 875B is adjacent to or below the third duplicator grating 875A. In one example of an embodiment including a third duplicator grating 875A and a fourth duplicator grating 875B, the two-dimensional expander grating 845A is positioned above the third duplicator grating 875A. In another example of an embodiment including a third duplicator grating 875A and a fourth duplicator grating 875B, the two-dimensional expander grating 845A is positioned below the fourth duplicator grating 875B. The in-coupler 815 may have a circular or oval shape. The first out-coupler 825A and the two-dimensional expander grating 845A may have a square or rectangular shape. The first duplicator grating 835A and the second duplicator grating 835B may have a square or rectangular shape.

[0048] 8C shows a K-space diagram 810 of the waveguide combiner 801. The K-space diagram 810 depicts the path of a virtual FOV generated from the microdisplay of the near-eye display system 100. The path of the virtual FOV is the intended image path using a rectangular lattice structure in the K-space domain. As shown in the K-space diagram 810, light from a light source, e.g., the virtual FOV, is incoupled by the incoupler 815 and diffracted as a beam along a path 821 to a first region 820. The beam incident on the first duplicator grating 835A is diffracted along a path 831A to a region 830L corresponding to the direction of the light that will propagate to the first duplicator grating 835A, where the beam re-encounters the first duplicator grating 835A and is diffracted back to the first region 820. The beam incident on the second duplicator grating 835B and diffracted by the first duplicator grating 835A back into the first region 820 is diffracted along path 831B to region 830R corresponding to the direction of light that will propagate into the second duplicator grating 835B, where it re-encounters the second duplicator grating 835B and is diffracted back into the first region 820. L and R represent "left" and "right," respectively. The beam incident on the first out-coupler 825A is diffracted by the first out-coupler 825A along path 851A to region 840L corresponding to the direction of light that will propagate into the two-dimensional expander grating 845A, and along path 851B to region 840R corresponding to the direction of light that will propagate into the two-dimensional expander grating 845A. Two-dimensional expander grating 845A then outcouples the light along paths 871A and 871B to user eyebox 808. The beam incident on two-dimensional expander grating 845A is diffracted by the two-dimensional expander grating along path 841A to region 850L corresponding to the direction of the light that will propagate into first outcoupler 825A, and along path 841B to region 860R corresponding to the direction of the light that will propagate into first outcoupler 825A.The first outcoupler 825A then outcouples the light along paths 861A and 861B to the user eyebox 808.

[0049] The locations of regions 830L and 830R must be different from the locations of regions 850L and 860R, respectively, to ensure that the new grid of diffracted beam regions corresponding to regions 850L and 860R does not align with the current grid of diffracted beam regions corresponding to regions 830L and 830R. Additionally, the placement of first duplicator grating 835A and second duplicator grating 835B creates an entirely new set of exit pupil regions that can reach the user's eyebox, and reduces the appearance of diffracted beam regions that create "ghost paths" that can result in secondary, shifted copies of the intended virtual content in the user's FOV. In some embodiments, the positions of regions 830L and 830R, and the positions of regions 850L and 860R, entail shifting the positions of regions 850L and 860R in K-space such that the shifted region positions are sufficiently far away (e.g., at least about 0.02k0 away) from the current K-space region positions 830L and 830R.

[0050] FIG. 8D shows a comparison of pupil replication graphs for waveguide combiner 801 and conventional grating vector architecture 802. The pupil replication graph represents an FOV angle of approximately (0 degrees, 0 degrees). As shown in FIG. 8D, each point on the pupil replication graph represents an exit pupil. Eyebox 880 of waveguide combiner 801 includes a greater number of exit pupils than eyebox 882 of conventional grating vector architecture 802. Eyebox 880 receiving a greater number of exit pupils results in increased exit pupil density for a waveguide combiner having the same thickness. FIG. 8D allows a direct comparison of pupil replication enhancement and increased exit pupil density for waveguide combiner 801. The increased pupil density for waveguide combiner 801 is achieved with a substrate having the same thickness as the waveguide combiner for conventional grating vector architecture 802. For example, the exit pupil density is at least about five times higher than for waveguide combiners with conventional grating vector architecture 802. As such, the substrate thickness does not need to be reduced or even increased while maintaining high exit pupil density. This mitigates the deleterious image effects of in-coupler rebounce, while also suppressing high-frequency nonuniformities.

[0051] Each grating vector architecture of each waveguide combiner herein can be realized in an actual waveguide combiner. For example, some potential variations include changing on which surface of the waveguide combiner each grating is located, changing the geometric boundary shape of the grating region, changing the grating vector magnitude, and / or using any number of stacked waveguide combiner layers. In some embodiments, in a single waveguide combiner layer, three display channels (red, green, and blue) propagate through the same layer and are diffracted from the same grating structure to deliver a virtual image to the user's eye. In other embodiments, in a three-waveguide layer system, each waveguide combiner layer can be designed to support only a single display color channel. The addition of additional gratings, the grating angles of all gratings, and the pitch of all gratings can be adjusted to achieve individual sets of optical properties.

[0052] Embodiments of near-eye display systems as described herein allow for increased exit pupil density, image sharpness, and image uniformity by including additional folding gratings. The additional folding gratings and replicator gratings on the diffractive waveguide combiner layer are designed to increase exit pupil density without substantially reducing the thickness of the waveguide combiner layer. Waveguide combiner layers without reduced thickness would experience the benefit of reduced in-coupler rebounce. Similarly, embodiments of near-eye display systems as described herein with additional folding gratings allow for the achieved benefit of reduced high-frequency non-uniformity in the projected image, particularly through the use of lasers. Reducing high-frequency non-uniformity in the projected image, in turn, increases image sharpness and image uniformity.

[0053] While the foregoing is directed to embodiments of the present disclosure, other and further implementations of the present disclosure may be contemplated without departing from the basic scope thereof, the scope of which is determined by the claims that follow.

Claims

1. a first surface; and a second surface; and an in-coupler located on the first surface and configured to receive a plurality of input beams and diffract a first subset of the beams and a second subset of the beams into total internal reflection (TIR) ​​in two opposite directions in K-space; a first folded grating located on the first surface and configured to receive the first subset of beams from the in-coupler in a first region in K-space and diffract the first subset of beams in TIR to a second region in K-space; a second folded grating located on the first surface and configured to receive the second subset of beams from the in-coupler in a third region in K-space and diffract the second subset of beams in TIR into the second region in K-space; a first outcoupler located on the first surface; and A waveguide combiner comprising:

2. 2. The waveguide combiner of claim 1, wherein the first outcoupler is configured to receive the first subset of beams from the first folded grating and the second subset of beams from the second folded grating in the second region in K space, diffract a first portion of the first subset of beams and a first portion of the second subset of beams into a fourth region in K space, and outcouple a second portion of the first subset of beams and a second portion of the second subset of beams.

3. The waveguide combiner of claim 2 , wherein the first out-coupler is a two-dimensional out-coupler.

4. 3. The waveguide combiner of claim 2, further comprising a second outcoupler located on the second surface and configured to receive the first subset of beams from the first folded grating and the second subset of beams from the second folded grating in the second region in K space, diffract the second portions of the first subset of beams and the second portions of the second subset of beams into a fifth region in K space, and outcouple the first portions of the first subset of beams and the first portions of the second subset of beams.

5. The waveguide combiner of claim 4 further comprising a third folded grating located on the second surface.

6. The waveguide combiner of claim 5 further comprising a fourth folded grating located on the second surface.

7. 7. The waveguide combiner of claim 6, wherein the fourth folded grating is located proximate to the third folded grating, and both the third folded grating and the fourth folded grating are located proximate to the second outcoupler.

8. a first surface; and a second surface; and an in-coupler located on the first surface and configured to receive a plurality of input beams and diffract the plurality of input beams into total internal reflection (TIR); a first replicator grating located on the first surface proximate to and below the incoupler, the first replicator grating configured to receive the plurality of input beams from the incoupler in a first region in K space and to diffract the plurality of input beams in TIR to a second region in K space; a second replicator grating on the first surface adjacent to and below the first replicator grating; a first outcoupler located on the first surface adjacent to or below the second replicator grating; a second outcoupler located on the second surface; and A waveguide combiner comprising:

9. The waveguide combiner of claim 8 , wherein the first replicator grating and the second replicator grating are square or rectangular in shape.

10. The waveguide combiner of claim 8 , wherein the first out-coupler or the second out-coupler is a two-dimensional out-coupler.

11. The waveguide combiner of claim 8 further comprising a third replicator grating located on the second surface.

12. The waveguide combiner of claim 11 further comprising a fourth replicator grating located on the second surface.

13. 13. The waveguide combiner of claim 12, wherein the fourth duplicator is located adjacent to and below the third duplicator grating, and the second outcoupler is located adjacent to and below the fourth duplicator grating.

14. a first surface; and a second surface; and an in-coupler located on the first surface and configured to receive a plurality of input beams and diffract a first subset of the beams and a second subset of the beams into total internal reflection (TIR) ​​in two opposite directions in K-space; a first folded grating located on the first surface and configured to receive the first subset of beams from the in-coupler in a first region in K-space and diffract the first subset of beams in TIR to a second region in K-space; a second folded grating located on the first surface and configured to receive the second subset of beams from the in-coupler in a third region in K-space and diffract the second subset of beams in TIR into the second region in K-space; an outcoupler located on the first surface and configured to receive the first subset of beams from the first folding grating and the second subset of beams from the second folding grating in the second region in K space, diffract a first portion of the first subset of beams and the first portion of the second subset of beams into a fourth region in K space, diffract a second portion of the first subset of beams and the second portion of the second subset of beams into a fifth region in K space, outcouple a third portion of the first subset of beams and the third portion of the second subset of beams from a sixth region, and outcouple a fourth portion of the first subset of beams and the fourth portion of the second subset of beams from a seventh region in K space; an expander grating located on the second surface and configured to receive the first portions of the first subset of beams and the first portions of the second subset of beams from the first and second folding gratings in the second region in K space, diffract a third portion of the first subset of beams and the third portion of the second subset of beams to the sixth region, diffract a fourth portion of the first subset of beams and the fourth portion of the second subset of beams to the seventh region in K space, outcouple the first portions of the first subset of beams and the first portion of the second subset of beams from the fourth region, and outcouple the second portions of the first subset of beams and the second portion of the second subset of beams from the fifth region in K space; A waveguide combiner comprising:

15. The waveguide combiner of claim 14 , wherein the in-coupler is circular or oval in shape.

16. The waveguide combiner of claim 14 , wherein the first folded grating and the second folded grating are trapezoidal in shape.

17. The waveguide combiner of claim 14 , wherein the outcoupler and the expander grating are square or rectangular in shape.

18. The waveguide combiner of claim 14 further comprising a third folded grating located on the second surface.

19. 20. The waveguide combiner of claim 18, further comprising a fourth folded grating located on the second surface.

20. 20. The waveguide combiner of claim 19, wherein the fourth folded grating is located proximate to the third folded grating, and both the third folded grating and the fourth folded grating are located proximate to the expander grating.

21. the light incoupled by the incoupler is diffracted into a beam along a first path to the first region corresponding to a direction of light that will propagate to the first folded grating and a second path to the second region corresponding to a direction of light that will propagate to the second folded grating; the beam incident on the first folded grating is diffracted along a third path to a region corresponding to a direction of light that will propagate through the first out-coupler and a second out-coupler on the second surface; the beam incident on the second folded grating is diffracted along a fourth path to the region corresponding to a direction of light that will propagate to the first outcoupler and the second outcoupler; the beam incident on the first out-coupler is diffracted by the first out-coupler along a fifth path to a region corresponding to a direction of light that will propagate to the second out-coupler, which then outcouples the light along a path to a user's eyebox; the beam incident on the second out-coupler is diffracted by the second out-coupler along a path to a region corresponding to a direction of light that will propagate into the first out-coupler, and the first out-coupler then out-couples the light along a path to the user's eyebox.

2. The waveguide combiner of claim 1.

22. the light incoupled by the incoupler is diffracted as a beam along a path to a first region; a beam incident on the first replicator grating is diffracted along a path to a region corresponding to the direction of light that will propagate into the first replicator grating, where the beam re-encounters the first replicator grating and is diffracted back to the first region; the beam diffracted back to the first region encounters the second replicator grating and is diffracted along a path to a region corresponding to the direction of light that will propagate to the second replicator grating, where the beam is diffracted back to the first region; the beam incident on the first out-coupler and diffracted by the second replicator grating back to the first region is diffracted by the first out-coupler along a path to a region corresponding to a direction of light that will propagate to the second out-coupler, which then outcouples the light along a path to a user's eyebox; the beam incident on the second out-coupler and diffracted by the second replicator grating back to the first region is diffracted by the second out-coupler along a path to a region corresponding to a direction of light that will propagate into the first out-coupler, which then outcouples the light along a path to the user's eyebox.

9. The waveguide combiner of claim 8.

23. the light incoupled by the incoupler is diffracted as a beam along a path to a first region; the beam incident on a first replicator grating is diffracted along a path to a region corresponding to the direction of light that will propagate into the first replicator grating, where the beam re-encounters the first replicator grating and is diffracted back to the first region; the beam incident on a second replicator grating and diffracted by the first replicator grating back to the first region is diffracted along a path to a region corresponding to the direction of light that will propagate to the second replicator grating, where it re-encounters the second replicator grating and is diffracted back to the first region; the beam incident on a first out-coupler is diffracted by the first out-coupler along a path to an area corresponding to a direction of light that will propagate into the expander grating, and along a path to an area corresponding to a direction of light that will propagate into the expander grating, which then outcouples the light along a path to a user's eyebox; the incident beam is diffracted by the expander grating along a path to an area corresponding to a direction of light that will propagate into the first out-coupler, and along a path to an area corresponding to a direction of light that will propagate into the first out-coupler, which then outcouples the light along a path to the user's eyebox.

15. The waveguide combiner of claim 14.

Images