Facebook Patent | Dispersion compensation in volume bragg grating-based waveguide display

Patent: Dispersion compensation in volume bragg grating-based waveguide display

Drawings: Click to check drawins

Publication Number: 20210055551

Publication Date: 20210225

Applicant: Facebook

Abstract

A waveguide display includes a substrate transparent to visible light, a coupler configured to couple display light into the substrate as guided wave in the substrate, and a first VBG and a second VBG coupled to the substrate. The coupler includes a diffractive coupler, a refractive coupler, or a reflective coupler. The first VBG is configured to diffract, at a first region of the first VBG, the display light in the substrate to a first direction, and diffract, at two or more regions of the first VBG along the first direction, the display light from the first region to a second direction towards the second VBG. The second VBG is configured to couple the display light from each of the two or more regions of the first VBG out of the substrate at two or more regions of the second VBG along the second direction.

Claims

1. A waveguide display comprising: a substrate transparent to visible light; and a first volume Bragg grating (VBG), a second VBG, and a third VBG coupled to the substrate, wherein the first VBG is configured to couple display light into the substrate as guided wave towards a first region of the second VBG; wherein the second VBG is configured to: diffract, at the first region of the second VBG, the display light from the first VBG to a first direction; and diffract, at two or more regions of the second VBG along the first direction, the display light from the first region to a second direction towards the third VBG; and wherein the third VBG is configured to couple the display light from each of the two or more regions of the second VBG out of the substrate at two or more regions of the third VBG along the second direction.

2. The waveguide display of claim 1, wherein the first VBG and the third VBG have a same grating vector in a plane perpendicular to a surface normal direction of the substrate.

3. The waveguide display of claim 1, wherein the first VBG, the second VBG, and the third VBG are configured to diffract the display light from a same field of view range and in a same wavelength range.

4. The waveguide display of claim 1, wherein each of the first VBG, the second VBG, and the third VBG includes a reflective VBG or a transmissive VBG.

5. The waveguide display of claim 1, wherein: the third VBG includes a transmissive VBG; and the second VBG overlaps with the third VBG in a see-through region of the waveguide display.

6. The waveguide display of claim 1, wherein at least one of the first VBG, the second VBG, or the third VBG includes a multiplexed VBG.

7. The waveguide display of claim 6, wherein: the first VBG includes a first set of VBGs; the third VBG includes a second set of VBGs; and each VBG in the first set of VBGs and a corresponding VBG in the second set of VBGs have a same grating vector in a plane perpendicular to a surface normal direction of the substrate and are configured to diffract the display light from a same field of view range and in a same wavelength range.

8. The waveguide display of claim 6, wherein at least one of the first VBG, the second VBG, or the third VBG includes VBGs in two or more holographic material layers.

9. The waveguide display of claim 8, further comprising a polarization convertor between two holographic material layers of the two or more holographic material layers.

10. The waveguide display of claim 1, further comprising an anti-reflection layer configured to reduce reflection of ambient light into the substrate.

11. The waveguide display of claim 1, further comprising an angular-selective transmissive layer configured to reflect, diffract, or absorb ambient light incident on the angular-selective transmissive layer with an incidence angle greater than a threshold value.

12. The waveguide display of claim 1, wherein: each of the second VBG and the third VBG is characterized by a respective thickness less than 100 .mu.m; and the waveguide display is characterized by an angular resolution less than 2 arcminutes.

13. The waveguide display of claim 1, wherein the first region of the second VBG and a second region of the two or more regions of the second VBG have a same grating vector in a plane perpendicular to a surface normal direction of the substrate.

14. The waveguide display of claim 1, further comprising: a light source configured to generate the display light; and projector optics configure to collimate the display light and direct the display light to the first VBG.

15. A waveguide display comprising: a substrate transparent to visible light; a coupler configured to couple display light into the substrate as guided wave in the substrate; and a first volume Bragg grating (VBG) and a second VBG coupled to the substrate, wherein the first VBG is configured to: diffract, at a first region of the first VBG, the display light in the substrate to a first direction; and diffract, at two or more regions of the first VBG along the first direction, the display light from the first region to a second direction towards the second VBG; and wherein the second VBG is configured to couple the display light from each of the two or more regions of the first VBG out of the substrate at two or more regions of the second VBG along the second direction.

16. The waveguide display of claim 15, wherein: the first VBG is characterized by a thickness less than 100 .mu.m; and the waveguide display is characterized by an angular resolution less than 2 arcminutes.

17. The waveguide display of claim 15, wherein: the second VBG includes a transmissive VBG; and the first VBG overlaps with the second VBG in a see-through region of the waveguide display.

18. The waveguide display of claim 15, wherein at least one of the first VBG or the second VBG includes VBGs in two or more holographic material layers.

19. The waveguide display of claim 15, wherein the coupler includes a diffractive coupler, a refractive coupler, or a reflective coupler.

20. The waveguide display of claim 15, wherein at least one of the first VBG or the second VBG includes a multiplexed VBG.

21. The waveguide display of claim 15, wherein each of the first VBG and the second VBG includes a transmissive VBG or a reflective VBG.

22. The waveguide display of claim 15, wherein the first region of the first VBG and a second region of the two or more regions of the first VBG have a same grating vector in a plane perpendicular to a surface normal direction of the substrate.

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This patent application claims priority to U.S. Provisional Patent Application Ser. No. 62/891,167, filed Aug. 23, 2019, entitled “Volume Bragg Grating-Based Waveguide Display,” the disclosure of which is hereby incorporated by reference in its entirety for all purposes.

BACKGROUND

[0002] An artificial reality system, such as a head-mounted display (HMD) or heads-up display (HUD) system, generally includes a near-eye display (e.g., in the form of a headset or a pair of glasses) configured to present content to a user via an electronic or optic display within, for example, about 10-20 mm in front of the user’s eyes. The near-eye display may display virtual objects or combine images of real objects with virtual objects, as in virtual reality (VR), augmented reality (AR), or mixed reality (MR) applications. For example, in an AR system, a user may view both images of virtual objects (e.g., computer-generated images (CGIs)) and the surrounding environment by, for example, seeing through transparent display glasses or lenses (often referred to as optical see-through).

[0003] One example of an optical see-through AR system may use a waveguide-based optical display, where light of projected images may be coupled into a waveguide (e.g., a transparent substrate), propagate within the waveguide, and be coupled out of the waveguide at different locations. In some implementations, the light of the projected images may be coupled into or out of the waveguide using a diffractive optical element, such as a grating. Light from the surrounding environment may pass through a see-through region of the waveguide and reach the user’s eyes as well.

SUMMARY

[0004] This disclosure relates generally to volume Bragg grating-based waveguide displays for near-eye display. More specifically, disclosed herein are techniques for expanding the eyebox, reducing display haze, reducing physical size, improving optical efficiency, reducing optical artifacts, and increasing field of view of optical see-through near-eye display systems using volume Bragg grating (VBG) couplers. Various inventive embodiments are described herein, including devices, systems, methods, and the like.

[0005] According to some embodiments, a waveguide display may include a substrate transparent to visible light, and a first VBG, a second VBG, and a third VBG coupled to the substrate. The first VBG may be configured to couple display light into the substrate as guided wave towards a first region of the second VBG. The second VBG may be configured to diffract, at the first region of the second VBG, the display light from the first VBG to a first direction (e.g., x direction), and diffract, at two or more regions of the second VBG along the first direction, the display light from the first region to a second direction (e.g., y direction) towards the third VBG. The third VBG may be configured to couple the display light from each of the two or more regions of the second VBG out of the substrate at two or more regions of the third VBG along the second direction. The first VBG and the third VBG may have a same grating vector in a plane (e.g., x-y plane) perpendicular to a surface normal direction of the substrate, and may have a same grating vector or opposite grating vectors in the surface normal (e.g., z) direction of the substrate. In some embodiments, the first region of the second VBG and the second region of the second VBG may have a same grating vector in a plane perpendicular to a surface normal direction of the substrate, and may have a same grating vector and/or opposite grating vectors in the surface normal direction of the substrate.

[0006] In some embodiments of the waveguide display, the first VBG, the second VBG, and the third VBG may be configured to diffract the display light from a same field of view range and in a same wavelength range. Each of the first VBG, the second VBG, and the third VBG includes a reflective VBG or a transmissive VBG. In some embodiments, the third VBG may include a transmissive VBG, and the second VBG may overlap with the third VBG in a see-through region of the waveguide display.

[0007] In some embodiments, at least one of the first VBG, the second VBG, or the third VBG may include a multiplexed VBG. The first VBG may include a first set of VBGs, the third VBG may include a second set of VBGs, and each VBG in the first set of VBGs and a corresponding VBG in the second set of VBGs may have a same grating vector in a plane perpendicular to a surface normal direction of the substrate and have a same grating vector or opposite grating vectors in the surface normal direction of the substrate, and may be configured to diffract the display light from a same field of view range and in a same wavelength range. In some embodiments, at least one of the first VBG, the second VBG, or the third VBG may include VBGs in two or more holographic material layers. In some embodiments, each of the second VBG and the third VBG may be characterized by a respective thickness less than 100 .mu.m, and the waveguide display may be characterized by an angular resolution less than 2 arcminutes.

[0008] In some embodiments, the waveguide display may include a polarization convertor between two holographic material layers of the two or more holographic material layers. In some embodiments, the waveguide display may include an anti-reflection layer configured to reduce reflection of ambient light into the substrate. In some embodiments, the waveguide display may include an angular-selective transmissive layer configured to reflect, diffract, or absorb ambient light incident on the angular-selective transmissive layer with an incidence angle greater than a threshold value. In some embodiments, the waveguide display may include a light source configured to generate the display light, and projector optics configure to collimate the display light and direct the display light to the first VBG.

[0009] According to certain embodiments, a waveguide display may include a substrate transparent to visible light, a coupler configured to couple display light into the substrate as guided wave in the substrate, and a first VBG and a second VBG coupled to the substrate. The first VBG may be configured to diffract, at a first region of the first VBG, the display light in the substrate to a first direction, and diffract, at two or more regions of the first VBG along the first direction, the display light from the first region to a second direction towards the second VBG. The second VBG may be configured to couple the display light from each of the two or more regions of the first VBG out of the substrate at two or more regions of the second VBG along the second direction. Each of the first VBG and the second VBG includes a transmissive VBG or a reflective VBG. In some embodiments, the coupler may include a diffractive coupler, a refractive coupler, or a reflective coupler.

[0010] In some embodiments, the first VBG may be characterized by a thickness less than 100 .mu.m, and the waveguide display may be characterized by an angular resolution less than 2 arcminutes. In some embodiments, the second VBG may include a transmissive VBG, and the first VBG may overlap with the second VBG in a see-through region of the waveguide display. In some embodiments, at least one of the first VBG or the second VBG may include VBGs in two or more holographic material layers. In some embodiments, at least one of the first VBG or the second VBG includes a multiplexed VBG.

[0011] This summary is neither intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. The subject matter should be understood by reference to appropriate portions of the entire specification of this disclosure, any or all drawings, and each claim. The foregoing, together with other features and examples, will be described in more detail below in the following specification, claims, and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Illustrative embodiments are described in detail below with reference to the following figures.

[0013] FIG. 1 is a simplified block diagram of an example of an artificial reality system environment including a near-eye display system according to certain embodiments.

[0014] FIG. 2 is a perspective view of an example of a near-eye display system in the form of a head-mounted display (HMD) device for implementing some of the examples disclosed herein.

[0015] FIG. 3 is a perspective view of an example of a near-eye display system in the form of a pair of glasses for implementing some of the examples disclosed herein.

[0016] FIG. 4 is a simplified diagram illustrating an example of an optical system in a near-eye display system.

[0017] FIG. 5 illustrates an example of an optical see-through augmented reality system including a waveguide display for exit pupil expansion according to certain embodiments.

[0018] FIG. 6 illustrates an example of an optical see-through augmented reality system including a waveguide display for exit pupil expansion according to certain embodiments.

[0019] FIG. 7A illustrates the spectral bandwidth of an example of a reflective volume Bragg grating (VBG) and the spectral bandwidth of an example of a transmissive surface-relief grating (SRG). FIG. 7B illustrates the angular bandwidth of an example of a reflective VBG and the angular bandwidth of an example of a transmissive SRG.

[0020] FIG. 8A illustrates an example of an optical see-through augmented reality system including a waveguide display and surface-relief gratings for exit pupil expansion according to certain embodiments. FIG. 8B illustrates an example of an eye box including two-dimensional replicated exit pupils according to certain embodiments.

[0021] FIG. 9A illustrates wave vectors of light diffracted by examples of surface-relief gratings for exit pupil expansion in a waveguide display and exit pupils for multiple colors.

[0022] FIG. 9B illustrates the field-of-view clipping by the examples of surface-relief gratings for exit pupil expansion in the waveguide display.

[0023] FIG. 10A illustrates an example of a volume Bragg grating-based waveguide display according to certain embodiments. FIG. 10B illustrates a top view of the example of the volume Bragg grating-based waveguide display shown in FIG. 10A. FIG. 10C illustrates a side view of the example of the volume Bragg grating-based waveguide display shown in FIG. 10A.

[0024] FIG. 11 illustrates light dispersion in an example of a volume Bragg grating-based waveguide display according to certain embodiments.

[0025] FIG. 12A illustrates an example of a volume Bragg grating (VBG). FIG. 12B illustrates the Bragg condition for the volume Bragg grating shown in FIG. 12A.

[0026] FIG. 13A illustrates an example of a reflective volume Bragg grating in a waveguide display according to certain embodiments. FIG. 13B illustrates an example of a reflective VBG in a waveguide display where light diffracted by the reflective VBG is not totally reflected and guided in the waveguide. FIG. 13C illustrates an example of a transmissive volume Bragg grating in a waveguide display according to certain embodiments. FIG. 13D illustrates an example of a transmissive VBG in a waveguide display where light diffracted by the transmissive VBG is not totally reflected and guided in the waveguide.

[0027] FIG. 14A illustrates the light dispersion by an example of a reflective volume Bragg grating in a waveguide display according to certain embodiments. FIG. 14B illustrates the light dispersion by an example of a transmissive volume Bragg grating in a waveguide display according to certain embodiments.

[0028] FIG. 15A illustrates a front view of an example of a volume Bragg grating-based waveguide display with exit pupil expansion and dispersion reduction according to certain embodiments. FIG. 15B illustrates a side view of the example of the volume Bragg grating-based waveguide display shown in FIG. 15A.

[0029] FIG. 16A is a front view of an example of a volume Bragg grating-based waveguide display with exit pupil expansion and dispersion reduction according to certain embodiments.

[0030] FIG. 16B is a side view of the example of the volume Bragg grating-based waveguide display shown in FIG. 16A.

[0031] FIG. 17A illustrates the propagation of light in different colors and from different fields of view in a reflective volume Bragg grating-based waveguide display according to certain embodiments. FIG. 17B illustrates the propagation of light in different colors and from different fields of view in a transmissive volume Bragg grating-based waveguide display according to certain embodiments.

[0032] FIG. 18 illustrates an example of a reflective volume Bragg grating-based waveguide display with exit pupil expansion and dispersion reduction according to certain embodiments.

[0033] FIG. 19 illustrates an example of a transmissive volume Bragg grating-based waveguide display with exit pupil expansion and form-factor reduction according to certain embodiments.

[0034] FIG. 20 illustrates another example of a transmissive volume Bragg grating-based waveguide display according to certain embodiments.

[0035] FIG. 21 illustrates an example of a volume Bragg grating-based waveguide display with exit pupil expansion, dispersion reduction, and form-factor reduction according to certain embodiments.

[0036] FIG. 22A illustrates another example of a volume Bragg grating-based waveguide display with exit pupil expansion, dispersion reduction, form-factor reduction, and power efficiency improvement according to certain embodiments. FIG. 22B illustrates examples of replicated exit pupils at an eyebox of the volume Bragg grating-based waveguide display shown in FIG. 22A.

[0037] FIG. 23A illustrates an example of a volume Bragg grating-based waveguide display with exit pupil expansion, dispersion reduction, and form-factor reduction according to certain embodiments. FIG. 23B illustrates an example of a volume Bragg grating-based waveguide display with exit pupil expansion, dispersion reduction, form-factor reduction, and power efficiency improvement according to certain embodiments.

[0038] FIG. 24A is a front view of an example of a volume Bragg grating-based waveguide display including an image projector and multiple polymer layers according to certain embodiments. FIG. 24B is a side view of the example of the volume Bragg grating-based waveguide display including the image projector and multiple polymer layers according to certain embodiments.

[0039] FIG. 25 illustrates an example of a volume Bragg grating-based waveguide display including multiple grating layers for different fields of view and/or light wavelengths according to certain embodiments.

[0040] FIG. 26 illustrates an example of a waveguide display including two multiplexed volume Bragg gratings and a polarization convertor between the two multiplexed volume Bragg gratings according to certain embodiments.

[0041] FIG. 27 illustrates an example of a waveguide display including an anti-reflection layer and an angular-selective transmissive layer according to certain embodiments.

[0042] FIG. 28 is a simplified block diagram of an example electronic system of an example near-eye display according to certain embodiments.

[0043] The figures depict embodiments of the present disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated may be employed without departing from the principles, or benefits touted, of this disclosure.

[0044] In the appended figures, similar components and/or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label.

DETAILED DESCRIPTION

[0045] This disclosure relates generally to volume Bragg grating (VBG)-based waveguide display for near-eye display systems. In a near-eye display system, it is generally desirable to expand the eyebox, reduce display haze, improve image quality (e.g., resolution and contrast), reduce physical size, increase power efficiency, and increase the field of view. In a waveguide-based near-eye display system, light of projected images may be coupled into a waveguide (e.g., a transparent substrate), propagate within the waveguide, and be coupled out of the waveguide at different locations to replicate exit pupils and expand the eyebox. Two or more gratings may be used to expand the exit pupil in two dimensions. In a waveguide-based near-eye display system for augmented reality applications, light from the surrounding environment may pass through at least a see-through region of the waveguide display (e.g., the transparent substrate) and reach the user’s eyes. In some implementations, the light of the projected images may be coupled into or out of the waveguide using diffractive optical elements, such as gratings. Couplers implemented using diffractive optical elements may cause dispersion between light of different colors due to the wavelength dependency of light diffraction. Therefore, images of different color components in a color image may not overlap and thus the resolution of the displayed image may be reduced. To reduce the dispersion and improve the resolution, thick transmissive and/or reflective VBG gratings may be used, which may be impractical in many cases and/or may cause significant display haze. For example, in some cases, transmissive VBG gratings with a thickness of greater than 1 mm may be used to achieve a desired resolution performance. Reflective VBG gratings with a lower thickness may be used to achieve the desired resolution performance. However, with reflection gratings, the gratings for two-dimensional pupil expansion may not overlap and thus the physical size of the waveguide display may be large.

[0046] According to certain embodiments, two VBG gratings (or two portions of a same grating) with matching grating vectors (e.g., having the same grating vector in a plane perpendicular to a surface normal direction of the transparent substrate and having the same and/or opposite grating vectors in the surface-normal direction of the transparent substrate, but recorded in different exposure durations to achieve different diffraction efficiencies) may be used to diffract display light and expand the exit pupil in one dimension. The two VBG gratings may compensate for the dispersion of display light caused by each other to reduce the overall dispersion, due to the opposite Bragg conditions (e.g., +1 order and -1 order diffractions) at the two VBG gratings. Therefore, thin VBG gratings may be used to achieve the desired resolution. Because of the dispersion compensation, thin transmissive VBG gratings may be used to achieve the desired resolution, and the gratings for the two-dimensional pupil expansion may at least partially overlap to reduce the physical size of the waveguide display.

[0047] In some embodiments, a first pair of VBG gratings (or two portions of a grating) may be used to expand the exit pupil in one dimension and compensate for the dispersion caused by each other, and a second pair of VBG gratings (or two portions of a grating) may be used to expand the exit pupil in another dimension and may compensate for the dispersion caused by each other. Thus, the exit pupil may be replicated in two dimensions and the resolution of the displayed images may be high in both dimensions.

[0048] In the following description, various inventive embodiments are described, including devices, systems, methods, and the like. For the purposes of explanation, specific details are set forth in order to provide a thorough understanding of examples of the disclosure. However, it will be apparent that various examples may be practiced without these specific details. For example, devices, systems, structures, assemblies, methods, and other components may be shown as components in block diagram form in order not to obscure the examples in unnecessary detail. In other instances, well-known devices, processes, systems, structures, and techniques may be shown without necessary detail in order to avoid obscuring the examples. The figures and description are not intended to be restrictive. The terms and expressions that have been employed in this disclosure are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof. The word “example” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment or design described herein as “example” is not necessarily to be construed as preferred or advantageous over other embodiments or designs.

[0049] FIG. 1 is a simplified block diagram of an example of an artificial reality system environment 100 including a near-eye display 120 in accordance with certain embodiments. Artificial reality system environment 100 shown in FIG. 1 may include near-eye display 120, an optional external imaging device 150, and an optional input/output interface 140, each of which may be coupled to an optional console 110. While FIG. 1 shows an example of artificial reality system environment 100 including one near-eye display 120, one external imaging device 150, and one input/output interface 140, any number of these components may be included in artificial reality system environment 100, or any of the components may be omitted. For example, there may be multiple near-eye displays 120 monitored by one or more external imaging devices 150 in communication with console 110. In some configurations, artificial reality system environment 100 may not include external imaging device 150, optional input/output interface 140, and optional console 110. In alternative configurations, different or additional components may be included in artificial reality system environment 100.

[0050] Near-eye display 120 may be a head-mounted display that presents content to a user. Examples of content presented by near-eye display 120 include one or more of images, videos, audio, or any combination thereof. In some embodiments, audio may be presented via an external device (e.g., speakers and/or headphones) that receives audio information from near-eye display 120, console 110, or both, and presents audio data based on the audio information. Near-eye display 120 may include one or more rigid bodies, which may be rigidly or non-rigidly coupled to each other. A rigid coupling between rigid bodies may cause the coupled rigid bodies to act as a single rigid entity. A non-rigid coupling between rigid bodies may allow the rigid bodies to move relative to each other. In various embodiments, near-eye display 120 may be implemented in any suitable form-factor, including a pair of glasses. Some embodiments of near-eye display 120 are further described below with respect to FIGS. 2 and 3. Additionally, in various embodiments, the functionality described herein may be used in a headset that combines images of an environment external to near-eye display 120 and artificial reality content (e.g., computer-generated images). Therefore, near-eye display 120 may augment images of a physical, real-world environment external to near-eye display 120 with generated content (e.g., images, video, sound, etc.) to present an augmented reality to a user.

[0051] In various embodiments, near-eye display 120 may include one or more of display electronics 122, display optics 124, and an eye-tracking unit 130. In some embodiments, near-eye display 120 may also include one or more locators 126, one or more position sensors 128, and an inertial measurement unit (IMU) 132. Near-eye display 120 may omit any of eye-tracking unit 130, locators 126, position sensors 128, and IMU 132, or include additional elements in various embodiments. Additionally, in some embodiments, near-eye display 120 may include elements combining the function of various elements described in conjunction with FIG. 1.

[0052] Display electronics 122 may display or facilitate the display of images to the user according to data received from, for example, console 110. In various embodiments, display electronics 122 may include one or more display panels, such as a liquid crystal display (LCD), an organic light emitting diode (OLED) display, an inorganic light emitting diode (ILED) display, a micro light emitting diode (.mu.LED) display, an active-matrix OLED display (AMOLED), a transparent OLED display (TOLED), or some other display. For example, in one implementation of near-eye display 120, display electronics 122 may include a front TOLED panel, a rear display panel, and an optical component (e.g., an attenuator, polarizer, or diffractive or spectral film) between the front and rear display panels. Display electronics 122 may include pixels to emit light of a predominant color such as red, green, blue, white, or yellow. In some implementations, display electronics 122 may display a three-dimensional (3D) image through stereoscopic effects produced by two-dimensional panels to create a subjective perception of image depth. For example, display electronics 122 may include a left display and a right display positioned in front of a user’s left eye and right eye, respectively. The left and right displays may present copies of an image shifted horizontally relative to each other to create a stereoscopic effect (e.g., a perception of image depth by a user viewing the image).

[0053] In certain embodiments, display optics 124 may display image content optically (e.g., using optical waveguides and couplers) or magnify image light received from display electronics 122, correct optical errors associated with the image light, and present the corrected image light to a user of near-eye display 120. In various embodiments, display optics 124 may include one or more optical elements, such as, for example, a substrate, optical waveguides, an aperture, a Fresnel lens, a convex lens, a concave lens, a filter, input/output couplers, or any other suitable optical elements that may affect image light emitted from display electronics 122. Display optics 124 may include a combination of different optical elements as well as mechanical couplings to maintain relative spacing and orientation of the optical elements in the combination. One or more optical elements in display optics 124 may have an optical coating, such as an anti-reflective coating, a reflective coating, a filtering coating, or a combination of different optical coatings.

[0054] Magnification of the image light by display optics 124 may allow display electronics 122 to be physically smaller, weigh less, and consume less power than larger displays. Additionally, magnification may increase a field of view of the displayed content. The amount of magnification of image light by display optics 124 may be changed by adjusting, adding, or removing optical elements from display optics 124. In some embodiments, display optics 124 may project displayed images to one or more image planes that may be further away from the user’s eyes than near-eye display 120.

[0055] Display optics 124 may also be designed to correct one or more types of optical errors, such as two-dimensional optical errors, three-dimensional optical errors, or any combination thereof. Two-dimensional errors may include optical aberrations that occur in two dimensions. Example types of two-dimensional errors may include barrel distortion, pincushion distortion, longitudinal chromatic aberration, and transverse chromatic aberration. Three-dimensional errors may include optical errors that occur in three dimensions. Example types of three-dimensional errors may include spherical aberration, comatic aberration, field curvature, and astigmatism.

[0056] Locators 126 may be objects located in specific positions on near-eye display 120 relative to one another and relative to a reference point on near-eye display 120. In some implementations, console 110 may identify locators 126 in images captured by external imaging device 150 to determine the artificial reality headset’s position, orientation, or both. A locator 126 may be an LED, a corner cube reflector, a reflective marker, a type of light source that contrasts with an environment in which near-eye display 120 operates, or any combination thereof. In embodiments where locators 126 are active components (e.g., LEDs or other types of light emitting devices), locators 126 may emit light in the visible band (e.g., about 380 nm to 750 nm), in the infrared (IR) band (e.g., about 750 nm to 1 mm), in the ultraviolet band (e.g., about 10 nm to about 380 nm), in another portion of the electromagnetic spectrum, or in any combination of portions of the electromagnetic spectrum.

[0057] External imaging device 150 may include one or more cameras, one or more video cameras, any other device capable of capturing images including one or more of locators 126, or any combination thereof. Additionally, external imaging device 150 may include one or more filters (e.g., to increase signal to noise ratio). External imaging device 150 may be configured to detect light emitted or reflected from locators 126 in a field of view of external imaging device 150. In embodiments where locators 126 include passive elements (e.g., retroreflectors), external imaging device 150 may include a light source that illuminates some or all of locators 126, which may retro-reflect the light to the light source in external imaging device 150. Slow calibration data may be communicated from external imaging device 150 to console 110, and external imaging device 150 may receive one or more calibration parameters from console 110 to adjust one or more imaging parameters (e.g., focal length, focus, frame rate, sensor temperature, shutter speed, aperture, etc.).

[0058] Position sensors 128 may generate one or more measurement signals in response to motion of near-eye display 120. Examples of position sensors 128 may include accelerometers, gyroscopes, magnetometers, other motion-detecting or error-correcting sensors, or any combination thereof. For example, in some embodiments, position sensors 128 may include multiple accelerometers to measure translational motion (e.g., forward/back, up/down, or left/right) and multiple gyroscopes to measure rotational motion (e.g., pitch, yaw, or roll). In some embodiments, various position sensors may be oriented orthogonally to each other.

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