Virtual and augmented reality display systems with luminescent microdisplays

Abstract

To provide a suitable virtual and augmented reality display system.SOLUTION: A wearable display system includes one or more light-emitting microdisplay (e.g., micro-LED display). The microdisplay may be a monochrome or a color microdisplay. The microdisplay may include an optical emitter array. An optical collimator may be utilized for narrowing the angle emission profile of emitted light by the optical emitter. When using a plurality of light-emitting microdisplays, the microdisplays may be located on a different side of an X-cube prism that receives a beam from different microdisplays and outputs the beam from the same plane of a cube. An optical combiner directs light to a projection optical system that outputs light to an ocular lens that relays light to a user's eyes. The ocular lens may output light to the user's eyes by wave front dispersion with different quantity and present virtual contents to the different depth plane.SELECTED DRAWING: Figure 11A

Description

Technical Field

[0001] (Claim of Priority) This application claims priority to U.S. Provisional Application No. 62 / 800,363, filed on February 1, 2019, entitled "VIRTUAL AND AUGMENTED REALITY DISPLAY SYSTEMS WITH EMISSIVE MICRO-DISPLAYS", U.S. Provisional Application No. 62 / 911,018, filed on October 4, 2019, entitled "AUGMENTED AND VIRTUAL REALITY DISPLAY SYSTEMS WITH SHARED DISPLAY FOR LEFT AND RIGHT EYES", and U.S. Provisional Application No. 62 / 786,199, filed on December 28, 2018, entitled "LOW MOTION-TO-PHOTON LATENCY ARCHITECTURE FOR AUGMENTED AND VIRTUAL REALITY DISPLAY SYSTEMS". The above applications are hereby incorporated by reference in their entirety into this specification. (Incorporation by Reference)

[0002] This application, by reference, refers to the following: U.S. Patent Application No. 14 / 555,585, filed on 27 November 2014 and published on 23 July 2015 as U.S. Patent Publication No. 2015 / 0205126; U.S. Patent Application No. 14 / 690,401, filed on 18 April 2015 and published on 22 October 2015 as U.S. Patent Publication No. 2015 / 0302652; U.S. Patent Application No. 14 / 212,961, filed on 14 March 2014 and issued on 16 August 2016, which is the current U.S. Patent No. 9,417,452; and U.S. Patent Application No. 14 / 212,961, filed on 14 July 2014 and published on 29 October 2015 as U.S. Patent Publication No. 2015 / 0309263. This incorporates the entirety of the following published U.S. Patent Application No. 14 / 331,218, U.S. Patent Application Publication No. 2018 / 0061121 (published March 1, 2018), U.S. Patent Application No. 16 / 221065 (filed December 14, 2018), U.S. Patent Application Publication No. 2018 / 0275410 (published September 27, 2018), U.S. Provisional Application No. 62 / 786,199 (filed December 28, 2018), U.S. Patent Application No. 16 / 221,359 (filed December 14, 2018), U.S. Provisional Application No. 62 / 702,707 (filed July 24, 2018), and U.S. Patent Application No. 15 / 481,255 (filed April 6, 2017). (Technical field)

[0003] This disclosure relates to display systems, and more specifically, to augmented and virtual reality display systems. [Background technology]

[0004] Modern computing and display technologies are driving the development of systems for so-called "virtual reality" or "augmented reality" experiences, in which digitally reproduced images or parts thereof are presented to the user in a manner that appears, or can be perceived, as real. Virtual reality, or "VR," scenarios typically involve the presentation of digital or virtual imagery without transparency to other real-world visual inputs, while augmented reality, or "AR," scenarios typically involve the presentation of digital or virtual imagery as an extension of the user's visualization of the real world around them. Mixed reality, or "MR," scenarios, are a type of AR scenario that typically involves virtual objects integrated into and responding to the natural world. For example, an MR scenario may include AR imagery that appears blocked by, or is perceived to interact with, objects in the real world in a different way.

[0005] Referring to Figure 1, an augmented reality scene 10 is depicted. The user of the AR technology sees a real-world park-like setting 20 featuring people, trees, buildings in the background, and a concrete platform 30. The user also perceives that they are "seeing" "virtual content" such as a robot figure 40 standing on the real-world platform 30 and a flying cartoon-like avatar character 50 that looks like an anthropomorphic bumblebee. These elements 50 and 40 are "virtual" in that they do not exist in the real world. The human visual perception system is complex, and it is difficult to produce AR technology that facilitates a comfortable, natural, and rich presentation of virtual image elements among other virtual or real-world image elements. [Overview of the project] [Means for solving the problem]

[0006] Some embodiments include a head-mounted display system. The display system comprises a head-mountable frame, a plurality of light-emitting microdisplays supported by the frame, and an eyepiece supported by the frame. The light-emitting microdisplays are configured to emit image light. The eyepiece receives the image light from the light-emitting microdisplays and is configured to direct the image light towards the user's eye, depending on whether the frame is mounted on the user.

[0007] Some other embodiments also include a head-mounted display system. The display system comprises a light-emitting microdisplay having an array of optical emitters corresponding to pixels, and a waveguide assembly having one or more waveguides. The array of optical emitters is configured to define an image. Each waveguide in the waveguide assembly comprises an internal coupling optical element configured to internally couple light from the microdisplay into the waveguide, and an external coupling optical element configured to externally couple the internally coupled light out of the waveguide. The waveguide assembly is configured to output the externally coupled light with a variable amount of wavefront divergence corresponding to a plurality of depth planes.

[0008] Some other embodiments also include a head-mounted display system. The display system comprises a head-mountable frame, a light-emitting microdisplay supported by the frame and comprising an array of groups of microemitters, a microlens array adjacent to the array of groups of microemitters, and a projection lens structure configured to receive light from the microlens array. Each group of microemitters in the array of groups of microemitters comprises a first microemitter configured to emit light of a first color, a second microemitter configured to emit light of a second color, and a third microemitter configured to emit light of a third color. Each group of microemitters also has associated microlenses that encompass the microemitters of the group of microemitters.

[0009] Some further embodiments include light-emitting microdisplay systems. The microdisplay system comprises an array of light emitters, each comprising a line of light emitters. Each line of light emitters is extended along an axis intersecting the line and configured to emit light of the same color. Multiple lines of light emitters constitute a group of lines. Each line in the group of lines is configured to emit light of a different color from at least one other line in the group of lines.

[0010] Some additional embodiments of the embodiment are provided below.

[0011] (Example 1) A head-mounted display system, A frame that can be mounted on the head, A plurality of light-emitting microdisplays supported by a frame, wherein the light-emitting microdisplays are configured to output image light, An eyepiece supported by a frame, wherein the eyepiece is configured to receive image light from an emitting microdisplay and direct the image light towards the user's eye, depending on whether the frame is mounted on the user. A head-mounted display system equipped with the following features.

[0012] (Example 2) The head-mounted display system according to Embodiment 2, further comprising an X-cube prism, with each light-emitting microdisplay facing a different side of the X-cube prism.

[0013] (Example 3) The output side of the X-cube prism faces the eyepiece, as described in Example 2 of the head-mounted display system.

[0014] (Example 4) The light-emitting microdisplay is a head-mounted display system according to any one of Examples 1-3, which is a monochromatic microdisplay.

[0015] (Example 5) The light-emitting microdisplay is a head-mounted display system according to any one of Examples 1-4, which includes an array of micro LEDs.

[0016] (Example 6) The head-mounted display system according to any one of Examples 1-3, further includes a plurality of arrays of optical collimators, each microdisplay has an associated array of optical collimators, and each array of optical collimators is configured to capture and reduce the angular emission profile of light from the microdisplay.

[0017] (Example 7) The head-mounted display system according to Example 6, each microdisplay includes an array of light emitters, and each light emitter has an associated optical collimator.

[0018] (Example 8) The head-mounted display system according to any one of Examples 6-7, the optical collimator includes a microlens.

[0019] (Example 9) The head-mounted display system according to any one of Examples 6-7, the optical collimator includes a nanolens.

[0020] (Example 10) The head-mounted display system according to any one of Examples 6-7, the optical collimator includes a reflective well.

[0021] (Example 11) The head-mounted display system according to any one of Examples 6-7, the optical collimator includes a metasurface.

[0022] (Example 12) The optical collimator is a head-mounted display system according to any one of Examples 6-7, comprising a liquid crystal lattice.

[0023] (Example 13) Each microdisplay comprises rows of light emitters, some rows of light emitters emit light of a different color from other rows of light emitters, and the light emitters in each row emit light of the same color. The head-mounted display system according to any one of Examples 1-12.

[0024] (Example 14) The optical collimator is a head-mounted display system according to Example 13, comprising a grating extending along the long axis of the associated row of light emitters.

[0025] (Example 15) Further comprising a waveguide assembly comprising one or more waveguides, each waveguide An internal coupling optical element configured to internally couple light from the microdisplay into the waveguide, And an external coupling optical element configured to externally couple the internally coupled light out of the waveguide [[ID=z8]]The head-mounted display system according to any one of Examples 1-14.

[0026] (Example 16) The waveguide assembly is configured to output externally coupled light with a variable amount of wavefront divergence corresponding to a plurality of depth planes. The head-mounted display system according to Example 15.

[0027] (Example 17) A head-mounted display system according to any one of Examples 15-16, wherein the waveguide assembly comprises multiple sets of waveguides, each set of waveguides comprising a dedicated waveguide for a primary color, each set of waveguides comprising an external coupling optical element configured to output light with wavefront divergence corresponding to a common depth plane, and different sets of waveguides output light with different amounts of wavefront divergence corresponding to different depth planes.

[0028] (Example 18) The head-mounted display system according to Embodiment 16, further comprising a variable focus lens element, wherein the waveguide assembly is located between a first variable focus lens element and a second variable focus lens element, the first variable focus lens element is configured to correct wavefront divergence of light output by the waveguide assembly, and the second variable focus lens element is configured to correct wavefront divergence of light from the outside to the second variable focus lens element.

[0029] (Example 19) The head-mounted display system according to Embodiment 15, wherein the waveguide assembly comprises a stack of waveguides, and the multiple light-emitting microdisplays are configured to output light of multiple primary colors, and the waveguide assembly comprises at least one dedicated waveguide for each primary color of light.

[0030] (Example 20) Multiple arrays of optical collimators, each microdisplay having an associated array of optical collimators, An X-cubic prism, and each light-emitting microdisplay faces a different side of the X-cubic prism, A projection optical system, wherein the projection optical system is configured to receive light from an X-cube prism and focus the received light toward a waveguide assembly. A head-mounted display system according to any one of Examples 15-19, further comprising the above.

[0031] (Example 21) At least two internal coupling optical elements of the waveguide are offset laterally in the direction of light propagating to the internal coupling optical elements, as seen in a direct front view. A head-mounted display system according to any one of Examples 15-20, wherein at least one of the array of optical collimators is configured to direct light into the corresponding side of an X-cube prism at an angle nonnormal to the corresponding side, and light passing through at least one of the optical collimators converges onto the corresponding internally coupled optical element, while light passing through the other optical collimators converges onto a different internally coupled optical element.

[0032] (Example 22) A head-mounted display system according to any one of Examples 15-20, further comprising a color filter between two neighboring waveguides in a stack of waveguides, the first of the neighboring waveguides preceding the second of the neighboring waveguides in an optical path extending from the microdisplay, and the color filter configured to selectively absorb light of a wavelength corresponding to the wavelength of light configured to be internally coupled by an internal coupling optical element of the first of the neighboring waveguides.

[0033] (Example 23) A third waveguide following a second waveguide in the vicinity within the optical path, Another color filter, which is configured to selectively absorb light of a wavelength corresponding to the wavelength of light, and which is configured to be internally coupled by an internal coupling optical element of a second nearby waveguide. The head-mounted display system according to Example 22, further comprising the above.

[0034] (Example 24) The head-mounted display system according to any one of Examples 15-23, wherein the positions of the internal coupling optical elements in each waveguide of the waveguide assembly overlap in the direction of light propagating to the internal coupling optical elements, as seen in a direct front view.

[0035] (Example 25) A head-mounted display system according to any one of Examples 15-23, further comprising an absorbing color filter on at least some of the main surfaces of the waveguide, wherein the absorbing color filter on the main surfaces of the waveguide is configured to absorb light of wavelengths that are internally coupled into the corresponding waveguide.

[0036] (Example 26) The internal coupling optical element is configured to internally couple light that propagates generally in the direction of propagation through an associated waveguide, the internal coupling optical element occupies an area having a width parallel to the direction of propagation and a length along an axis intersecting the direction of propagation, the length being greater than the width, as described in any one of Examples 1-25.

[0037] (Example 27) A head-mounted display system, A light-emitting microdisplay comprising an array of light emitters corresponding to pixels, wherein the array of light emitters is configured to define an image, A waveguide assembly comprising one or more waveguides, wherein each waveguide is An internal coupling optical element configured to internally couple light from a microdisplay into a waveguide, An external coupling optical element configured to externally couple internally coupled light out of the waveguide, Equipped with, The waveguide assembly is configured to output externally coupled light with a variable amount of wavefront divergence corresponding to multiple depth planes. A head-mounted display system equipped with the following features.

[0038] (Example 28) The light-emitting microdisplay is a microLED display in the head-mounted display system described in Example 27.

[0039] (Example 29) A head-mounted display system according to any one of Examples 27-28, further comprising an array of optical collimators adjacent to an array of optical emitters, each optical emitter having an associated optical collimator, each optical collimator configured to receive and focus light emitted by the associated optical emitter.

[0040] (Example 30) The optical collimator is a head-mounted display system according to Example 29, comprising a microlens.

[0041] (Example 31) The optical collimator is a head-mounted display system as described in Example 29, comprising a nanolens.

[0042] (Example 32) The optical collimator is a head-mounted display system according to Example 29, comprising a reflective well.

[0043] (Example 33) The optical collimator is a head-mounted display system according to Example 29, comprising a metasurface.

[0044] (Example 34) The optical collimator is a head-mounted display system according to Example 29, comprising a liquid crystal grating.

[0045] (Example 35) A head-mounted display system according to any one of Examples 27-34, further comprising a projection optical system configured to focus light from a light-emitting microdisplay onto an internally coupled optical element of one or more waveguides.

[0046] (Example 36) Each individual light emitter is configured to emit light of one of several primary colors. A waveguide assembly comprises multiple sets of waveguides. Each set of waveguides is equipped with a dedicated waveguide for each primary color, and each set of waveguides is equipped with an external coupling optical element configured to output light with wavefront divergence corresponding to a common depth plane, and different sets of waveguides output light with different amounts of wavefront divergence corresponding to different depth planes. A head-mounted display system according to any one of Examples 27-35.

[0047] (Example 37) A head-mounted display system according to any one of Examples 27-35, further comprising a variable focus lens element, wherein the waveguide assembly is located between a first variable focus lens element and a second variable focus lens element, the first variable focus lens element is configured to correct wavefront divergence of light output by the waveguide assembly, and the second variable focus lens element is configured to correct wavefront divergence of light from the outside to the second variable focus lens element.

[0048] (Example 38) Waveguide assembly comprising a stack of waveguides, a head-mounted display system according to any one of Examples 27-37.

[0049] (Example 39) The head-mounted display system according to Embodiment 38, further comprising a color filter between two neighboring waveguides in a stack of waveguides, the first of the neighboring waveguides preceding the second of the neighboring waveguides in the optical path extending from the microdisplay, and the color filter configured to selectively absorb light of a wavelength corresponding to the wavelength of light, so as to be internally coupled by the internal coupling optical element of the first of the neighboring waveguides.

[0050] (Example 40) A third waveguide follows a second waveguide in the vicinity within the optical path, Another color filter, which is configured to selectively absorb light of a wavelength corresponding to the wavelength of light, and which is configured to be internally coupled by an internal coupling optical element of a second nearby waveguide. The head-mounted display system according to Example 39, further comprising the above.

[0051] (Example 41) The head-mounted display system according to Examples 38-40, further comprising an absorbing color filter on at least some of the main surfaces of the waveguide, wherein the absorbing color filter on the main surfaces of the waveguide is configured to absorb light of wavelengths that are internally coupled into the corresponding waveguide.

[0052] (Example 42) An internal coupling optical element is configured to internally couple light that propagates generally in the direction of propagation through an associated waveguide, the internal coupling optical element occupies an area having a width parallel to the direction of propagation and a length along an axis intersecting the direction of propagation, the length being greater than the width, as described in any one of Examples 27-41.

[0053] (Example 43) A head-mounted display system, A frame that can be mounted on the head, A light-emitting microdisplay supported by a frame, the light-emitting microdisplay comprises an array of groups of microemitters, each group of microemitters is A first microemitter configured to emit light of a first color, A second microemitter configured to emit light of a second color, A third microemitter configured to emit a third color of light and A light-emitting microdisplay equipped with, A microlens array adjacent to an array of groups of microemitters, wherein each group of microemitters has an associated microlens that encloses the microemitters of the group of microemitters, A projection lens structure configured to receive light from a microlens array and A head-mounted display system equipped with the following features.

[0054] (Example 44) The waveguide assembly further comprises first, second, and third optical internal coupling regions positioned to receive light from a projection lens structure, The head-mounted display system according to Embodiment 43, wherein the projection lens structure is configured to focus light from a first microemitter onto a first internal coupling region, light from a second microemitter onto a second internal coupling region, and light from a third microemitter onto a third internal coupling region.

[0055] (Example 45) The head-mounted display system according to Embodiment 44, wherein the waveguide assembly comprises first, second, and third waveguides, each having a first, second, and third optical internal coupling region.

[0056] (Example 46) The head-mounted display system according to any one of Examples 44-45, wherein the first, second, and third optical internal coupling regions are laterally shifted so as to be visible from the projection lens structure.

[0057] (Example 47) The head-mounted display system according to any one of Examples 44-45, wherein the first and second optical internal coupling regions overlap as visible from the projection lens structure.

[0058] (Example 48) A head-mounted display system according to any one of Examples 44-47, further comprising a color filter between a first internal optical coupling region and a second internal optical coupling region, wherein the color filter is configured to selectively absorb light of a wavelength corresponding to the wavelength of light configured to be internally coupled by the first internal coupling optical element.

[0059] (Example 49) The head-mounted display system according to any one of Examples 44-48, further comprising other color filters configured to selectively absorb light of wavelengths corresponding to the wavelengths of light, wherein the second and third optical internal coupling regions overlap as visible from the projection lens structure and are configured to be internally coupled by the second internal coupling optical element.

[0060] (Example 50) A head-mounted display system according to any one of Examples 44-49, further comprising an absorbing color filter on at least some of the main surfaces of the waveguide, wherein the absorbing color filter on the main surfaces of the waveguide is configured to absorb light of wavelengths internally coupled into the corresponding waveguide.

[0061] (Example 51) A waveguide assembly comprises multiple sets of waveguides. Each set of waveguides includes one dedicated waveguide for the first, second, or third color. Each set of waveguides includes an external coupling optical element configured to output light with wavefront divergence corresponding to a common depth plane. Different sets of waveguides emit light with different amounts of wavefront divergence corresponding to different depth planes. A head-mounted display system according to any one of Examples 44-50.

[0062] (Example 52) A head-mounted display system according to any one of Examples 44-50, further comprising a variable focus lens element, wherein the waveguide assembly is located between a first variable focus lens element and a second variable focus lens element, the first variable focus lens element being configured to correct wavefront divergence of light output to the user's eye by the waveguide assembly, and the second variable focus lens element being configured to correct wavefront divergence of light from the outside to the user's eye.

[0063] (Example 53) An internal coupling optical element is configured to internally couple light with coupled light generally propagating in the propagation direction through an associated waveguide, the internal coupling optical element occupies an area having a width parallel to the propagation direction and a length along an axis intersecting the propagation direction, the length being greater than the width, as described in any one of Examples 44-52.

[0064] (Example 54) A head-mounted display system according to any one of Examples 43-53, wherein the first color is green, the second color is blue, and the third color is red.

[0065] (Example 55) The light-emitting microdisplay is a head-mounted display system according to any one of Examples 43-54, comprising an array of microLEDs.

[0066] (Example 56) The head-mounted display system according to any one of Examples 43-55, wherein the light-emitting microdisplay is one of several similar microdisplays, further comprising an X-cube prism, and each light-emitting microdisplay faces a different side of the X-cube prism.

[0067] (Example 57) The head-mounted display system according to Example 56, wherein the output side of the X-cube prism is configured to output light from an emitting microdisplay into a projection lens structure.

[0068] (Example 58) A light-emitting microdisplay system, It has an array of optical emitters with a line of optical emitters, The optical emitter of each line is extended along the axis intersecting the line, Each line's light emitter is configured to emit light of the same color. Multiple lines of the optical emitter form a group of lines. Each line in the group of lines is configured to emit light of a different color from at least one other line in the group. Light-emitting microdisplay system.

[0069] (Example 59) Each group on Line is A first line of light emitter configured to emit light of a first color, A second line of light emitter configured to emit a second color of light, A third line of light emitter configured to emit a third color and A light-emitting microdisplay system according to Example 58, comprising the above.

[0070] (Example 60) The light-emitting microdisplay system according to Example 59, wherein the first color is green, the second color is blue, and the third color is red.

[0071] (Example 61) A light-emitting microdisplay system according to any one of Examples 58-59, further comprising a lens array across an array of optical emitters, wherein the lens array is configured to receive light from the optical emitters and reduce the angular emission profile of the received light.

[0072] (Example 62) The light-emitting microdisplay system according to Example 61, wherein the lens array is a nanolens array comprising multiple diffraction gratings.

[0073] (Example 63) The light-emitting microdisplay system according to Example 62, wherein the diffraction grating is extended along an axis parallel to the line associated with the light emitter.

[0074] (Example 64) The light-emitting microdisplay system according to Example 64, wherein the individual diffraction gratings extend across the entire associated line of the optical emitter.

[0075] (Example 65) A light-emitting microdisplay system according to any one of Examples 62-64, wherein the diffraction grating has lines of material within the substrate, and the material forming the lines has a different refractive index from the material forming the substrate.

[0076] (Example 66) A light-emitting microdisplay system according to any one of Examples 58-65, wherein the line pitch is 30-300 nm.

[0077] (Example 67) A light-emitting microdisplay system according to any one of Examples 58-66, wherein the line depth is 10 to 1,000 nm.

[0078] (Example 68) A light-emitting microdisplay system according to any one of Examples 58-67, wherein the line depth and pitch vary between each line in a group of lines.

[0079] (Example 69) A light-emitting microdisplay system according to any one of Examples 58-68, wherein the refractive index of the material forming the lines is 1.5 to 2.5.

[0080] (Example 70) A light-emitting microdisplay system according to any one of Examples 58-69, wherein the refractive index of the substrate is 1.5 to 2.5.

[0081] (Example 71) A projection optical system configured to focus light from a lens array, A waveguide assembly comprising one or more waveguides, each waveguide is An internal coupling optical element configured to internally couple light from a projection optical system into a waveguide, An external coupling optical element configured to externally couple internally coupled light out of the waveguide, A waveguide assembly comprising A light-emitting microdisplay system according to any one of Examples 58-70, further comprising the above.

[0082] (Example 72) The internal coupling optical elements of each waveguide are laterally shifted relative to the internal coupling optical elements of other waveguides, as viewed from the line of sight of the projection optical system. Different internally coupled optical elements are configured to internally couple light of different colors. The lens array is configured to direct light of different colors along the optical path toward different internally coupled optical elements. The light-emitting microdisplay system described in Example 71.

[0083] (Example 73) A head-mounted display system according to any one of Examples 71-72, further comprising a projection optical system configured to focus light from a light-emitting microdisplay onto an internally coupled optical element of one or more waveguides.

[0084] (Example 74) Each individual light emitter is configured to emit light of one of several primary colors. A waveguide assembly comprises multiple sets of waveguides. Each set of waveguides is equipped with a dedicated waveguide for each primary color, and each set of waveguides is equipped with an external coupling optical element configured to output light with wavefront divergence corresponding to a common depth plane, and different sets of waveguides output light with different amounts of wavefront divergence corresponding to different depth planes. A head-mounted display system according to any one of Examples 58-73.

[0085] (Example 75) A head-mounted display system according to any one of Examples 71-73, further comprising a variable focus lens element, wherein the waveguide assembly is located between a first variable focus lens element and a second variable focus lens element, the first variable focus lens element is configured to correct wavefront divergence of light output by the waveguide assembly, and the second variable focus lens element is configured to correct wavefront divergence of light from the outside to the second variable focus lens element.

[0086] (Example 76) The waveguide assembly comprises a stack of waveguides, A color filter is further provided between two neighboring waveguides in the waveguide stack. The first nearby waveguide precedes the second nearby waveguide in the optical path extending from the microdisplay. The color filter is configured to selectively absorb light of a wavelength corresponding to the wavelength of light that is configured to be internally coupled by the internal coupling optical element of a first nearby waveguide. A head-mounted display system according to any one of Examples 71-75.

[0087] (Example 77) A third waveguide follows a second waveguide in the vicinity within the optical path, Another color filter, which is configured to selectively absorb light of a wavelength corresponding to the wavelength of light, and which is configured to be internally coupled by an internal coupling optical element of a second nearby waveguide. The head-mounted display system according to Example 76, further comprising the above.

[0088] (Example 78) A head-mounted display system according to any one of Examples 71-77, further comprising an absorbing color filter on at least some of the main surfaces of the waveguide, wherein the absorbing color filter on the main surfaces of the waveguide is configured to absorb light of wavelengths that are internally coupled into the corresponding waveguide.

[0089] (Example 79) An internal coupling optical element is configured to internally couple light that propagates generally in the direction of propagation through an associated waveguide, the internal coupling optical element occupies an area having a width parallel to the direction of propagation and a length along an axis intersecting the direction of propagation, the length being greater than the width, as described in any one of Examples 71-78. This specification also provides, for example, the following: (Item 1) A head-mounted display system, A frame that can be mounted on the head, A plurality of light-emitting microdisplays supported by the frame, wherein each light-emitting microdisplay is configured to output image light, An eyepiece supported by the frame, wherein the eyepiece is configured to receive image light from the light-emitting microdisplay and direct the image light towards the user's eye, in response to the frame being mounted on the user. A head-mounted display system equipped with the following features. (Item 2) The head-mounted display system according to item 1, further comprising an X-cube prism, wherein each of the light-emitting microdisplays faces a different side of the X-cube prism. (Item 3) The output side of the X-cube prism faces the eyepiece, in the head-mounted display system described in item 2. (Item 4) The head-mounted display system described in item 2, wherein the light-emitting microdisplay is a monochrome microdisplay. (Item 5) The light-emitting microdisplay is a head-mounted display system according to item 1, comprising an array of microLEDs. (Item 6) The head-mounted display system according to item 1, further comprising multiple arrays of optical collimators, each microdisplay having an associated array of optical collimators, and each array of optical collimators configured to capture and reduce the angular emission profile of light from the microdisplay. (Item 7) The head-mounted display system according to item 6, wherein each microdisplay comprises an array of optical emitters, and each optical emitter has an associated optical collimator. (Item 8) The optical collimator is a head-mounted display system according to item 6, comprising a microlens. (Item 9) The optical collimator is a head-mounted display system according to item 6, comprising a nanolens. (Item 10) The optical collimator comprises a reflective well, as described in item 6, for the head-mounted display system. (Item 11) The optical collimator is a head-mounted display system according to item 6, comprising a metasurface. (Item 12) The optical collimator is a head-mounted display system according to item 6, comprising a liquid crystal grid. (Item 13) The head-mounted display system described in item 6, wherein each microdisplay comprises rows of light emitters, some rows of light emitters emitting light of a different color from other rows of light emitters, and each row of light emitters emitting light of the same color. (Item 14) The head-mounted display system according to item 13, wherein the optical collimator comprises a grating that extends along the long axis of the associated row of the optical emitter. (Item 15) A waveguide assembly further comprises one or more waveguides, each waveguide being: An internal coupling optical element configured to internally couple light from the microdisplay into the waveguide, An external coupling optical element configured to externally couple the internally coupled light out of the waveguide, A head-mounted display system as described in item 1, comprising: (Item 16) The head-mounted display system according to item 15, wherein the waveguide assembly is configured to output the externally coupled light with a variable amount of wavefront divergence corresponding to multiple depth planes. (Item 17) The waveguide assembly comprises a plurality of sets of waveguides, each set of waveguides comprising a dedicated waveguide for a primary color, each set of waveguides comprising an external coupling optical element configured to output light with wavefront divergence corresponding to a common depth plane, and different sets of waveguides output light with different amounts of wavefront divergence corresponding to different depth planes, as described in item 16. (Item 18) The head-mounted display system according to item 16, further comprising a variable focus lens element, wherein the waveguide assembly is located between a first variable focus lens element and a second variable focus lens element, the first variable focus lens element is configured to correct wavefront divergence of light output by the waveguide assembly, and the second variable focus lens element is configured to correct wavefront divergence of light from the outside to the second variable focus lens element. (Item 19) The head-mounted display system according to item 15, wherein the waveguide assembly comprises a stack of waveguides, the plurality of light-emitting microdisplays are configured to output light of a plurality of primary colors, and the waveguide assembly comprises at least one dedicated waveguide for each primary color of light. (Item 20) Multiple arrays of optical collimators, each microdisplay having an associated array of optical collimators, An X-cubic prism, wherein each of the light-emitting microdisplays faces a different side of the X-cubic prism, A projection optical system, wherein the projection optical system is configured to receive light from the X-cube prism and focus the received light toward the waveguide assembly, and A head-mounted display system as described in item 19, further comprising the features described above. (Item 21) The internal coupling optical elements of at least two waveguides are offset laterally in the direction of light propagating to the internal coupling optical elements, as seen in a direct front view. The head-mounted display system according to item 20, wherein at least one of the array of optical collimators is configured to direct light into the corresponding side of the X-cube prism at an angle nonnormal to the corresponding side, and light passing through at least one of the optical collimators converges onto the corresponding internal coupling optical element, while light passing through the other optical collimators converges onto a different internal coupling optical element. (Item 22) The head-mounted display system according to item 19, further comprising a color filter between two neighboring waveguides in a stack of waveguides, the first of the neighboring waveguides preceding the second of the neighboring waveguides in an optical path extending from the microdisplay, and the color filter being configured to selectively absorb light of a wavelength corresponding to the wavelength of light configured to be internally coupled by the internal coupling optical element of the first of the neighboring waveguides. (Item 23) A third waveguide following the second waveguide in the vicinity within the optical path, Other color filters, wherein the other color filters are configured to selectively absorb light of a wavelength corresponding to the wavelength of light, which is configured to be internally coupled by the internal coupling optical element of the second of the nearby waveguides. A head-mounted display system as described in item 22, further comprising the features described above. (Item 24) The head-mounted display system according to item 19, wherein the positions of the internal coupling optical elements in each waveguide of the waveguide assembly overlap in the direction of light propagating to the internal coupling optical elements, as seen in a direct front view. (Item 25) The head-mounted display system according to item 19, further comprising an absorbing color filter on at least some of the main surfaces of the waveguide, wherein the absorbing color filter on the main surfaces of the waveguide is configured to absorb light of wavelengths that are internally coupled into the corresponding waveguide. (Item 26) The head-mounted display system according to item 1, wherein the internal coupling optical element is configured to internally couple light that propagates generally in the propagation direction through an associated waveguide, and the internal coupling optical element occupies an area having a width parallel to the propagation direction and a length along an axis intersecting the propagation direction, wherein the length exceeds the width. (Item 27) A head-mounted display system, A light-emitting microdisplay comprising an array of light emitters corresponding to pixels, wherein the array of light emitters is configured to define an image, A waveguide assembly comprising one or more waveguides, each waveguide is An internal coupling optical element configured to internally couple light from the microdisplay into the waveguide, An external coupling optical element configured to externally couple the internally coupled light out of the waveguide, Equipped with, The waveguide assembly is configured to output the externally coupled light with a variable amount of wavefront divergence corresponding to multiple depth planes. A head-mounted display system equipped with the following features. (Item 28) The head-mounted display system described in item 27, wherein the light-emitting microdisplay is a microLED display. (Item 29) The head-mounted display system according to item 27, further comprising an array of optical collimators adjacent to an array of optical emitters, each of which has an associated optical collimator, each optical collimator configured to receive and focus light output by the associated optical emitter. (Item 30) The optical collimator is a head-mounted display system according to item 29, comprising a microlens. (Item 31) The optical collimator is a head-mounted display system as described in item 29, comprising a nanolens. (Item 32) The optical collimator comprises a reflective well, as described in item 29, for the head-mounted display system. (Item 33) The optical collimator comprises a metasurface, as described in item 29, for the head-mounted display system. (Item 34) The optical collimator is a head-mounted display system according to item 29, comprising a liquid crystal grating. (Item 35) The head-mounted display system according to item 27, further comprising a projection optical system configured to focus light from the light-emitting microdisplay onto the internally coupled optical elements of one or more waveguides. (Item 36) Each of the aforementioned light emitters is configured to emit light of one of several primary colors. The waveguide assembly comprises a plurality of sets of waveguides, Each set of waveguides is equipped with a dedicated waveguide for each primary color, and each set of waveguides is equipped with an external coupling optical element configured to output light with wavefront divergence corresponding to a common depth plane, and different sets of waveguides output light with different amounts of wavefront divergence corresponding to different depth planes. The head-mounted display system described in item 27. (Item 37) The head-mounted display system according to item 27, further comprising a variable focus lens element, wherein the waveguide assembly is located between a first variable focus lens element and a second variable focus lens element, the first variable focus lens element is configured to correct wavefront divergence of light output by the waveguide assembly, and the second variable focus lens element is configured to correct wavefront divergence of light from the outside to the second variable focus lens element. (Item 38) The waveguide assembly comprises a stack of waveguides, as described in item 27, for the head-mounted display system. (Item 39) The head-mounted display system according to item 38, further comprising a color filter between two neighboring waveguides in a stack of waveguides, the first of the neighboring waveguides preceding the second of the neighboring waveguides in an optical path extending from the microdisplay, and the color filter being configured to selectively absorb light of a wavelength corresponding to the wavelength of light configured to be internally coupled by the internal coupling optical element of the first of the neighboring waveguides. (Item 40) A third waveguide following the second waveguide in the vicinity within the optical path, Other color filters, wherein the other color filters are configured to selectively absorb light of a wavelength corresponding to the wavelength of light, which is configured to be internally coupled by the internal coupling optical element of the second of the nearby waveguides. A head-mounted display system as described in item 39, further comprising the features described above. (Item 41) The head-mounted display system according to item 38, further comprising an absorbing color filter on at least some of the main surfaces of the waveguide, wherein the absorbing color filter on the main surfaces of the waveguide is configured to absorb light of wavelengths that are internally coupled into the corresponding waveguide. (Item 42) The internal coupling optical element is configured to internally couple light with internally coupled light generally propagating in the propagation direction through an associated waveguide, the internal coupling optical element occupies an area having a width parallel to the propagation direction and a length along an axis intersecting the propagation direction, wherein the length exceeds the width, as described in item 38 of the head-mounted display system. (Item 43) A head-mounted display system, A frame that can be mounted on the head, A light-emitting microdisplay supported by the frame, the light-emitting microdisplay comprises an array of groups of microemitters, each group of microemitters is A first microemitter configured to emit light of a first color, A second microemitter configured to emit light of a second color, A third microemitter configured to emit a third color of light and A light-emitting microdisplay equipped with, A microlens array adjacent to an array of groups of microemitters, wherein each group of microemitters has associated microlenses that enclose the microemitters of the group of microemitters, A projection lens structure configured to receive light from the aforementioned microlens array and A head-mounted display system equipped with the following features. (Item 44) The waveguide assembly further comprises first, second, and third optical internal coupling regions positioned to receive light from the projection lens structure, The head-mounted display system according to item 43, wherein the projection lens structure is configured to focus light from the first microemitter onto the first internal coupling region, focus light from the second microemitter onto the second internal coupling region, and focus light from the third microemitter onto the third internal coupling region. (Item 45) The head-mounted display system according to item 44, wherein the waveguide assembly comprises first, second, and third waveguides, each having the first, second, and third optical internal coupling regions. (Item 46) The head-mounted display system according to item 45, wherein the first, second, and third optical internal coupling regions are shifted laterally so as to be visible from the projection lens structure. (Item 47) The head-mounted display system according to item 45, wherein the first and second optical internal coupling regions overlap so as to be visible from the projection lens structure. (Item 48) The head-mounted display system according to item 47, further comprising a color filter between the first internal optical coupling region and the second internal optical coupling region, wherein the color filter is configured to selectively absorb light of a wavelength corresponding to the wavelength of light configured to be internally coupled by the first internal coupling optical element. (Item 49) The second and third optical internal coupling regions overlap, as can be seen from the projection lens structure. The head-mounted display system according to item 48, further comprising other color filters configured to selectively absorb light of a wavelength corresponding to the wavelength of light configured to be internally coupled by the second internal coupling optical element. (Item 50) The head-mounted display system according to item 45, further comprising an absorbing color filter on at least some of the main surfaces of the waveguide, wherein the absorbing color filter on the main surfaces of the waveguide is configured to absorb light of wavelengths that are internally coupled into the corresponding waveguide. (Item 51) The waveguide assembly comprises a plurality of sets of waveguides, Each set of waveguides includes one dedicated waveguide for each of the first, second, or third colors. Each set of waveguides includes an external coupling optical element configured to output light with wavefront divergence corresponding to a common depth plane. Different sets of waveguides emit light with different amounts of wavefront divergence corresponding to different depth planes. The head-mounted display system described in item 44. (Item 52) The head-mounted display system according to item 44, further comprising a variable focus lens element, wherein the waveguide assembly is located between a first variable focus lens element and a second variable focus lens element, the first variable focus lens element is configured to correct wavefront divergence of light output to the user's eye by the waveguide assembly, and the second variable focus lens element is configured to correct wavefront divergence of light from the outside to the user's eye. (Item 53) The internal coupling optical element is configured to internally couple light with internally coupled light generally propagating in the propagation direction through an associated waveguide, the internal coupling optical element occupies an area having a width parallel to the propagation direction and a length along an axis intersecting the propagation direction, wherein the length exceeds the width, as described in item 44 of the head-mounted display system. (Item 54) The head-mounted display system according to item 43, wherein the first color is green, the second color is blue, and the third color is red. (Item 55) The light-emitting microdisplay comprises an array of microLEDs, as described in item 43, for the head-mounted display system. (Item 56) The head-mounted display system according to item 43, wherein the light-emitting microdisplay is one of several similar microdisplays, further comprising an X-cube prism, and each of the light-emitting microdisplays faces a different side of the X-cube prism. (Item 57) The head-mounted display system according to item 56, wherein the output side of the X-cube prism is configured to output light from the light-emitting microdisplay into the projection lens structure. (Item 58) A light-emitting microdisplay system, An array of optical emitters with a line of optical emitters Equipped with, The optical emitter of each line is extended along an axis intersecting the line, Each line's light emitter is configured to emit light of the same color. The multiple lines of the optical emitter constitute a group of lines, Each line in the group of lines is configured to emit light of a different color from at least one other line in the group of lines. Light-emitting microdisplay system. (Item 59) Each group of the aforementioned lines is A first line of light emitter configured to emit light of a first color, A second line of light emitter configured to emit a second color of light, A third line of light emitter configured to emit a third color and A light-emitting microdisplay system as described in item 58, comprising: (Item 60) The light-emitting microdisplay system described in item 59, wherein the first color is green, the second color is blue, and the third color is red. (Item 61) The light-emitting microdisplay system according to item 58, further comprising a lens array across an array of light emitters, wherein the lens array is configured to receive light from the light emitters and reduce the angular emission profile of the received light. (Item 62) The light-emitting microdisplay system according to item 61, wherein the lens array is a nanolens array comprising multiple diffraction gratings. (Item 63) The diffraction grating is extended along an axis parallel to the line associated with the optical emitter, as described in item 62, for the light-emitting microdisplay system. (Item 64) The light-emitting microdisplay system according to item 63, wherein each of the diffraction gratings extends across the entire line associated with the optical emitter. (Item 65) The light-emitting microdisplay system according to item 61, wherein the diffraction grating comprises lines of material within a substrate, and the material forming the lines has a different refractive index from the material forming the substrate. (Item 66) The line pitch is 30 to 300 nm, as described in item 65, for the light-emitting microdisplay system. (Item 67) The light-emitting microdisplay system described in item 65, wherein the depth of the line is 10 to 1,000 nm. (Item 68) The light-emitting microdisplay system according to item 65, wherein the depth and pitch of the lines vary between each line in the group of lines. (Item 69) The light-emitting microdisplay system according to item 65, wherein the refractive index of the material forming the line is 1.5 to 2.5. (Item 70) The light-emitting microdisplay system according to item 69, wherein the refractive index of the substrate is 1.5 to 2.5. (Item 71) A projection optical system configured to focus light from the aforementioned lens array, A waveguide assembly comprising one or more waveguides, each waveguide is An internal coupling optical element configured to internally couple light from the projection optical system into the waveguide, An external coupling optical element configured to externally couple the internally coupled light out of the waveguide, A waveguide assembly comprising A light-emitting microdisplay system as described in item 61, further comprising the features described above. (Item 72) The internal coupling optical elements of each waveguide are laterally shifted relative to the internal coupling optical elements of other waveguides, as viewed from the line of sight of the projection optical system. Different internally coupled optical elements are configured to internally couple light of different colors. The lens array is configured to direct light of different colors along the optical path toward different internally coupled optical elements. A light-emitting microdisplay system as described in item 71. (Item 73) The head-mounted display system according to item 71, further comprising a projection optical system configured to focus light from the light-emitting microdisplay onto the internally coupled optical elements of one or more waveguides. (Item 74) Each of the aforementioned light emitters is configured to emit light of one of several primary colors. The waveguide assembly comprises a plurality of sets of waveguides, Each set of waveguides is equipped with a dedicated waveguide for each primary color, and each set of waveguides is equipped with an external coupling optical element configured to output light with wavefront divergence corresponding to a common depth plane, and different sets of waveguides output light with different amounts of wavefront divergence corresponding to different depth planes. A head-mounted display system as described in item 71. (Item 75) The head-mounted display system according to item 71, further comprising a variable focus lens element, wherein the waveguide assembly is located between a first variable focus lens element and a second variable focus lens element, the first variable focus lens element is configured to correct wavefront divergence of light output by the waveguide assembly, and the second variable focus lens element is configured to correct wavefront divergence of light from the outside to the second variable focus lens element. (Item 76) The waveguide assembly comprises a stack of waveguides, A color filter is further provided between two neighboring waveguides in the stack of waveguides. The first of the aforementioned nearby waveguides precedes the second of the aforementioned nearby waveguides in the optical path extending from the microdisplay. The color filter is configured to selectively absorb light of a wavelength corresponding to the wavelength of light that is configured to be internally coupled by the internal coupling optical element of the first waveguide in the vicinity. A head-mounted display system as described in item 71. (Item 77) A third waveguide following the second waveguide in the vicinity within the optical path, Other color filters, wherein the other color filters are configured to selectively absorb light of a wavelength corresponding to the wavelength of light, which is configured to be internally coupled by the internal coupling optical element of the second of the nearby waveguides. A head-mounted display system as described in item 76, further comprising the features described above. (Item 78) The head-mounted display system according to item 71, further comprising an absorbing color filter on at least some of the main surfaces of the waveguide, wherein the absorbing color filter on the main surfaces of the waveguide is configured to absorb light of wavelengths that are internally coupled into the corresponding waveguide. (Item 79) The internal coupling optical element is configured to internally couple light with internally coupled light generally propagating in the propagation direction through an associated waveguide, the internal coupling optical element occupies an area having a width parallel to the propagation direction and a length along an axis intersecting the propagation direction, wherein the length exceeds the width, as described in item 71. [Brief explanation of the drawing]

[0090] [Figure 1] Figure 1 illustrates the user's view of augmented reality (AR) through an AR device.

[0091] [Figure 2] Figure 2 illustrates a conventional display system for simulating a three-dimensional image for the user.

[0092] [Figure 3] Figures 3A-3C illustrate the relationship between the radius of curvature and the radius of focus.

[0093] [Figure 4A] Figure 4A illustrates the representation of the accommodation-vergence response of the human visual system.

[0094] [Figure 4B] Figure 4B illustrates an example of different near and far accommodative states and convergence / divergence motion states of a pair of user eyes.

[0095] [Figure 4C] Figure 4C illustrates an example of how the upper and lower figures represent a user viewing content through a display system.

[0096] [Figure 4D] Figure 4D illustrates another embodiment of the representation of a user viewing content through a display system.

[0097] [Figure 5] Figure 5 illustrates aspects of an approach to simulating a 3D image by correcting wavefront divergence.

[0098] [Figure 6] Figure 6 illustrates an example of a waveguide stack for outputting image information to the user.

[0099] [Figure 7] Figure 7 illustrates an example of an output beam produced by a waveguide.

[0100] [Figure 8] Figure 8 illustrates an embodiment of stacked eyepieces, where each depth plane contains an image formed using multiple different primary colors.

[0101] [Figure 9A] Figure 9A shows a cross-sectional side view of an embodiment of a stacked waveguide set, each including an internally coupled optical element.

[0102] [Figure 9B] Figure 9B shows a perspective view of an embodiment of the multiple stacked waveguides shown in Figure 9A.

[0103] [Figure 9C] Figure 9C shows top and bottom plan views of the embodiment of the multiple stacked waveguides shown in Figures 9A and 9B.

[0104] [Figure 9D]Figure 9D shows top and bottom plan views of another embodiment of multiple stacked waveguides.

[0105] [Figure 9E] Figure 9E illustrates an embodiment of a wearable display system.

[0106] [Figure 10] Figure 10 illustrates an embodiment of a wearable display system that includes a light projection system having a spatial light modulator and a separate light source.

[0107] [Figure 11A] Figure 11A illustrates an embodiment of a wearable display system with a light projection system having multiple light-emitting microdisplays.

[0108] [Figure 11B] Figure 11B illustrates an embodiment of a light-emitting microdisplay with an array of optical emitters.

[0109] [Figure 12] Figure 12 illustrates another embodiment of a wearable display system, which includes a light projection system having multiple light-emitting microdisplays and associated light redirection structures.

[0110] [Figure 13A] Figure 13A illustrates a side view embodiment of a wearable display system comprising an eyepiece with an optical projection system having multiple light-emitting microdisplays and a waveguide with overlapping and laterally offset optically coupled optical elements.

[0111] [Figure 13B] Figure 13B illustrates another embodiment of a wearable display system, which includes a light projection system having multiple light-emitting microdisplays configured to direct light to a single light internal coupling area of ​​an eyepiece.

[0112] [Figure 14] Figure 14 illustrates an embodiment of a wearable display system with a single-emitting microdisplay.

[0113] [Figure 15] Figure 15 shows a side view of an embodiment of an eyepiece having a stack of waveguides with overlapping internally coupled optical elements.

[0114] [Figure 16] Figure 16 shows a side view of an embodiment of a waveguide stack with a color filter to reduce afterimage or crosstalk between waveguides.

[0115] [Figure 17] Figure 17 illustrates the upper and lower view embodiments of the eyepiece lenses shown in Figures 15 and 16.

[0116] [Figure 18] Figure 18 illustrates another embodiment of the upper and lower views of the eyepieces shown in Figures 15 and 16.

[0117] [Figure 19A] Figure 19A shows a side view of an embodiment of an eyepiece having a stack of waveguides with overlapping and laterally offset internally coupled optical elements.

[0118] [Figure 19B] Figure 19B shows a side view of an embodiment of the eyepiece lens shown in Figure 19A, with a color filter to reduce afterimage or crosstalk between waveguides.

[0119] [Figure 20A] Figure 20A illustrates the upper and lower view embodiments of the eyepiece lens shown in Figures 19A and 19B.

[0120] [Figure 20B] Figure 20B illustrates another embodiment of the upper and lower views of the eyepiece in Figures 19A and 19B.

[0121] [Figure 21] Figure 21 shows a side view of an example of re-bouncement within a waveguide.

[0122] [Figure 22A] Figures 22A-22C illustrate upper and lower embodiments of an eyepiece having an internally coupled optical element configured to reduce re-bounce. [Figure 22B] Figures 22A-22C illustrate upper and lower embodiments of an eyepiece having an internally coupled optical element configured to reduce re-bounce. [Figure 22C] Figures 22A-22C illustrate upper and lower embodiments of an eyepiece having an internally coupled optical element configured to reduce re-bounce.

[0123] [Figure 23A] Figures 23A-23C illustrate additional upper and lower embodiments of an eyepiece having an internally coupled optical element configured to reduce re-bounce. [Figure 23B] Figures 23A-23C illustrate additional upper and lower embodiments of an eyepiece having an internally coupled optical element configured to reduce re-bounce. [Figure 23C] Figures 23A-23C illustrate additional upper and lower embodiments of an eyepiece having an internally coupled optical element configured to reduce re-bounce.

[0124] [Figure 24A] Figure 24A illustrates an example of the angular emission profiles of light emitted by individual light emitters of a light-emitting microdisplay and light captured by a projection optical system.

[0125] [Figure 24B] Figure 24B illustrates an example of narrowing the angular emission profile using an array of optical collimators.

[0126] [Figure 25A] Figure 25A illustrates an embodiment of a side view of an array of tapered reflective wells for directing light into a projection optical system.

[0127] [Figure 25B] Figure 25B illustrates an example of a side view of an asymmetric tapered reflective well.

[0128] [Figure 26] Figures 26A-26C illustrate examples of differences in the optical path for the optical emitter at different positions relative to the center line of the upper lens.

[0129] [Figure 27] Figure 27 illustrates an example of a side view of an individual optical emitter in a light-emitting microdisplay with an upper layer nanolens array.

[0130] [Figure 28] Figure 28 is a perspective view of an embodiment of the light-emitting microdisplay shown in Figure 27.

[0131] [Figure 29] Figure 29 illustrates an embodiment of a wearable display system, including the full-color light-emitting microdisplay shown in Figure 28.

[0132] [Figure 30A] Figure 30A illustrates an embodiment of a wearable display system comprising an emissive microdisplay and an associated array of optical collimators.

[0133] [Figure 30B] Figure 30B illustrates an embodiment of an optical projection system, each comprising multiple light-emitting microdisplays, each with an associated array of optical collimators.

[0134] [Figure 30C]FIG. 30C illustrates an embodiment of a wearable display system with a plurality of emissive microdisplays, each with an associated array of optical collimators.

[0135] [Figure 31] FIGS. 31A and 31B illustrate an embodiment of a waveguide assembly having a variable focus element for varying the wavefront divergence of light to a viewer.

BRIEF DESCRIPTION OF THE DRAWINGS

[0136] An augmented reality (AR) or virtual reality (VR) system may display virtual content to a user or viewer. This content may be displayed, for example, on a head-mounted display as part of eyewear that projects image information onto the user's eyes. Additionally, if the system is an AR system, the display may also transmit light from the surrounding environment to the user's eyes, enabling a view of the surrounding environment. As used herein, it should be understood that a "head-mounted" or "head-mountable" display is a display that can be mounted on a user's head or viewer.

[0137] Many head-mounted display systems utilize transmissive or reflective spatial light modulators to form the images presented to the user. A light source emits light, which is directed at the spatial light modulator, which then modulates the light, which is then directed at the user. A lens structure may be provided between the light source and the spatial light modulator to focus the light from the light source onto the spatial light modulator. Unfortunately, the light source and associated optics can add bulk and weight to the display system. This bulk or weight can negatively affect the comfort of the display system and the ability to wear the system for extended periods of time.

[0138] In addition, the frame rate limits of some display systems have been found to cause visual discomfort. Some display systems use a spatial light modulator to form an image. Many spatial light modulators utilize the movement of optical elements to modulate the intensity of the light output by the spatial light modulator, thereby forming an image. For example, a MEMS-based spatial light modulator can utilize a movable mirror to modulate incident light, while an LCoS-based display can utilize the movement of liquid crystal molecules to modulate light. Other AR or VR systems can utilize a scanning fiber display where the end of an optical fiber physically moves across an area while outputting light. The light output by the optical fiber is adjusted in timing according to the position of the end of the fiber, thereby virtually mimicking pixels at different locations and thereby forming an image. The requirement for the optical fiber, mirror, and liquid crystal molecules to physically move limits the speed at which individual pixels can change states using these optical elements and also constrains the frame rate of the display.

[0139] Such limits can cause visual discomfort, for example, due to motion blur and / or inconsistencies between the orientation of the user's head and the image being displayed. For example, there may be a latency in detecting the orientation of the user's head and presenting an image that matches that orientation. The user's head may move during the time period between detecting the orientation and presenting the image to the user. However, the image presented may correspond to a view of an object from a different orientation. Such an inconsistency between the orientation of the user's head and the image presented can cause discomfort (e.g., nausea) to the user.

[0140] In addition, scanning fiber displays can present other undesirable optical artifacts due to the small cross-section of the fiber, for example, requiring the use of a high-intensity light source to form an image with a desired apparent brightness. Suitable high-intensity light sources include lasers, which output coherent light. Unfortunately, the use of coherent light can cause optical artifacts.

[0141] Advantageously, display systems utilizing light-emitting microdisplays as described herein can enable low weight and compact form factors, which can also provide high frame rates and low motion blur. Preferably, the microdisplay is a light-emitting microdisplay, which offers the advantages of high brightness and high pixel density. In some embodiments, the light-emitting microdisplay is a microLED display. In some other embodiments, the light-emitting microdisplay is a microOLED display. In some embodiments, the light-emitting microdisplay comprises an array of photoemitters having pitches of less than 10 μm, less than 8 μm, less than 6 μm, less than 5 μm, or less than 2 μm, including, for example, 1 to 5 μm, and emitter sizes of 2 μm or less, less than 1.7 μm or less, or less than 1.3 μm or less. In some embodiments, the emitter size is within a range having the upper limit of the above size and a lower limit of 1 μm. In some embodiments, the emitter size-to-pitch ratio is 1:1–1:5, 1:2–1:4, or 1:2–1:3, which may have advantages in terms of individual control of the emitter and efficient utilization of light emitted by the eyepiece, as will be further discussed herein.

[0142] In some embodiments, multiple light-emitting microdisplays may be used to form images for a head-mounted display system. The light containing image information for forming these images may be referred to as image light. It should be understood that the image light may vary in wavelength, intensity, polarization, etc. The light-emitting microdisplays output the image light to an eyepiece, which then relays the light to the user's eye.

[0143] In some embodiments, multiple light-emitting microdisplays may be positioned on different sides of an optical combiner, such as an X-cube prism or a dichroic X-cube. The X-cube prism receives light rays from different microdisplays on different faces of the cube and outputs the light rays from the same face of the cube. The output light may be directed towards a projection optical system configured to focus or concentrate the image light onto an eyepiece.

[0144] In some embodiments, the multiple light-emitting microdisplays comprise a monochrome microdisplay, which is configured to emit light of a single primary color. Combining various primary colors forms a full-color image. In some other embodiments, one or more of the light-emitting microdisplays may have subpixels configured to emit light of two or more, but not all, of the primary colors utilized by the display system. For example, a single light-emitting microdisplay may have subpixels that emit blue and green light, while separate light-emitting microdisplays on different faces of an X-cube may have pixels configured to emit red light. In some embodiments, the multiple microdisplays are a full-color display, each comprising pixels formed from multiple subpixels, each configured to emit light of, for example, different primary colors. Advantageously, combining the light from multiple full-color microdisplays can increase the display brightness and dynamic range.

[0145] It should be understood that light-emitting microdisplays may comprise an array of optical emitters. These optical emitters may emit light with a Lambertian angular emission profile. Undesirably, such an angular emission profile can "waste" light, as only a small portion of the emitted light may ultimately enter the eyepiece. In some embodiments, an optical collimator may be used to narrow the angular emission profile of the light emitted by the optical emitters. As used herein, an optical collimator is an optical structure that narrows the angular emission profile of incident light. That is, the optical collimator receives light from associated optical emitters with a relatively wide initial angular emission profile and outputs that light with a narrower angular emission profile than the wide initial angular emission profile. In some embodiments, the rays of light exiting the optical collimator are more parallel to the rays of light received by the optical collimator before they are transmitted through the collimator and exit therefrom. Embodiments of optical collimators include microlenses, nanolenses, reflective wells, metasurfaces, and liquid crystal gratings. In some embodiments, the optical collimator may be configured to steer the light and ultimately focus it onto an optically coupled optical element that is shifted to a different side. In some embodiments, each optical emitter has its own dedicated optical collimator. The optical collimator is preferably positioned directly adjacent to or in contact with the optical emitter and captures a large proportion of the light emitted by the associated optical emitter.

[0146] In some embodiments, a single light-emitting microdisplay may be used to direct light towards the eyepiece. For example, the single light-emitting microdisplay may be a full-color display comprising light emitters that emit light of different primary colors. In some embodiments, the light emitters may form localized groups within a common area, each group comprising a light emitter that emits light of each primary color. In such embodiments, each group of light emitters may share a common microlens. Advantageously, light of different colors from different light emitters may follow different paths through the microlens, which may manifest as light of different primary colors incident on different internally coupled optical elements of the eyepiece, as discussed herein.

[0147] In some embodiments, a full-color microdisplay may comprise repeating groups of light emitters of the same primary color. For example, a microdisplay may include rows of light emitters, where each individual row of light emitters is configured to emit light of the same color. Thus, different rows may emit light of different primary colors. In addition, a microdisplay may have an associated array of light collimators configured to direct light to a desired location on the eyepiece, for example, an associated internally coupled optical element. Advantageously, while the individual light emitters of such a full-color microdisplay may not be positioned to form a high-quality full-color image so that they are directly visible on the microdisplay, the lens array appropriately directs the light from the light emitters to the eyepiece, which combines the monochrome images formed by the light emitters of different colors, thereby forming a high-quality full-color image.

[0148] In some embodiments, the eyepiece receiving image light from a microdisplay may comprise a waveguide assembly. The waveguide area of ​​the waveguide assembly onto which image light is incident may include an internal coupling optical element that internally couples the incident image light so that the light propagates through the waveguide by total internal reflection (TIR). In some embodiments, the waveguide assembly may comprise a stack of waveguides, each having an associated internal coupling optical element. Different internal coupling optical elements may be configured to internally couple light of different colors so that different waveguides can be configured to propagate light of different colors within them. The waveguide may include an external coupling optical element that externally couples the light propagating within it so that the externally coupled light propagates toward the user's eye. In some other embodiments, the waveguide assembly may comprise a single waveguide having an associated internal coupling optical element configured to internally couple light of different primary colors.

[0149] In some embodiments, the internal coupling optical elements are shifted laterally as seen from the projection optical system. Different internal coupling optical elements may be configured to internally couple light of different colors. Preferably, the image light of different colors follows different paths to the eyepiece and therefore collides with different corresponding internal coupling optical elements.

[0150] In some other embodiments, other types of eyepieces or optical systems may be used to relay the image light to the user's eye. For example, as discussed herein, the eyepiece may include one or more waveguides that propagate the image light therein by TIR. In another embodiment, the eyepiece may include a basin mirror combiner with a translucent mirror that serves both to direct the image light to the viewer and to allow a view of the surrounding environment.

[0151] In some embodiments, the eyepiece may be configured to selectively output light with different amounts of wavefront divergence, providing a plurality of virtual depth planes (also referred to herein simply as “depth planes”) of virtual content perceived as being at different distances from the user. For example, the eyepiece may comprise a plurality of waveguides, each having an externally coupled optical element with different refractive powers for outputting light with different amounts of wavefront divergence. In some other embodiments, a variable focus element may be provided between the eyepiece and the user’s eye. The variable focus element may be configured to dynamically change its refractive power to provide desired wavefront divergence for specific virtual content. In some embodiments, as an alternative to, or in addition to, the waveguide optical structure for providing refractive power, the display system may also include a plurality of lenses that provide, or in addition to, refractive power.

[0152] In addition to the compact form factor and high frame rate discussed above, in some embodiments, light-emitting microdisplays can offer one or more of the following advantages. For example, microdisplays can offer significantly small pixel pitch and high pixel density. Microdisplays can also offer high brightness and efficiency. For example, the light emitter of a light-emitting microdisplay may only consume power to emit light when the light emitter is required to provide content at a certain brightness. This is in contrast to other display technologies where the light source can illuminate the entire panel of pixels, regardless of whether some of those pixels are dark. Furthermore, it should be understood that the human visual system integrates received light over time, and the light emitters of light-emitting microdisplays, such as microLEDs, have a high duty cycle, which is advantageous (for example, the light emitter in a microdisplay may have a short activation period to rise from "off" to a fully "on" state and, correspondingly, a short period to fall from the "on" state to the "off" state, allowing the light emitter to emit light at the on-level for a large percentage of each cycle). As a result, the power used to generate an image with a given perceived brightness may be less compared to conventional display technologies with lower duty cycles. In some embodiments, the duty cycle may be 70% or more, 80% or more, or 90% or more. In some embodiments, the duty cycle may be about 99%. In addition, as described herein, microdisplays can facilitate significantly higher frame rates, which may offer advantages including reducing mismatch between the user's head position and the displayed content.

[0153] Here, we refer to drawings where the same reference number refers to the same part throughout. Unless otherwise indicated, the drawings are schematic and not necessarily drawn to exact scale.

[0154] Figure 2 illustrates a conventional display system for simulating a three-dimensional image for a user. It should be understood that when a user's eyes are spaced apart and viewing a real object in space, each eye may have a slightly different view of the object and may form an image of the object in different locations on the retina of each eye. This may be called binocular parallax and can be used by the human visual system to provide a sense of depth. Conventional display systems simulate binocular parallax by presenting two distinctly different images 190, 200, one for each eye 210, 220, with slightly different views of the same virtual object, corresponding to the view of the virtual object that each eye would see as a real object at a desired depth. These images provide binocular cues that the user's visual system can interpret to derive a sense of depth.

[0155] Continuing with Figure 2, images 190 and 200 are spaced 230 units away from eyes 210 and 220 on the z-axis. The z-axis is parallel to the viewer's optical axis when the eye is fixated on an object at optical infinity directly in front of the viewer. Images 190 and 200 are flat and at a fixed distance from eyes 210 and 220. Based on slightly different views of the virtual object in the images presented to eyes 210 and 220, respectively, the eyes may rotate so that the image of the object comes to the corresponding point on the respective retina of the eye, maintaining monobiocular vision. This rotation can converge the lines of sight of eyes 210 and 220 to a point in space where the virtual object is perceived to exist. As a result, the provision of three-dimensional images conventionally involves manipulating the convergence and divergence movements of the user's eyes 210 and 220 and providing binocular cues that the human visual system interprets to provide depth perception.

[0156] However, generating a realistic and comfortable perception of depth is difficult. It should be understood that light from an object at different distances from the eye has wavefronts with different amounts of divergence. Figures 3A-3C illustrate the relationship between distance and ray divergence. The distances between the object and the eye 210 are expressed in the order of decreasing distances R1, R2, and R3. As shown in Figures 3A-3C, the rays diverge more as the distance to the object decreases. Conversely, as the distance increases, the rays become more collimated. In other words, the light field generated by a point (object or part of an object) can be said to have a spherical wavefront curvature, which is a function of the distance the point is from the user's eye. The curvature increases with decreasing distance between the object and the eye 210. Only a monocular eye 210 is illustrated in Figures 3A-3C and various other figures herein for the sake of clarity in the illustration, but the discussion with respect to the eye 210 can be applied to both eyes 210 and 220 of the viewer.

[0157] Continuing to refer to Figures 3A-3C, light from an object that a viewer's eye is fixated on may have different wavefront divergences. Due to the different wavefront divergences, the light may be focused differently by the eye's lens, which may require the lens to take on different shapes and form focused images on the eye's retina. If a focused image is not formed on the retina, the resulting retinal blur acts as a cue for accommodation, causing a change in the shape of the eye's lens until a focused image is formed on the retina. For example, a cue for accommodation may trigger relaxation or contraction of the ciliary muscle surrounding the eye's lens, thereby modulating the force applied to the low ligament that holds the lens, and thus changing the shape of the eye's lens until the retinal blur of the fixed image is eliminated or minimized, thereby forming a focused image of the fixed object on the eye's retina (e.g., the fovea). The process by which the lens of the eye changes shape can be called accommodation, and the shape of the lens required to form a focused image of the object being fixed on onto the retina of the eye (e.g., the fovea) can be called the accommodative state.

[0158] Referring here to Figure 4A, the representation of the accommodation-convergence-divergence response of the human visual system is illustrated. Eye movement to fixate on an object allows the eye to receive light from the object, and the light forms an image on each retina of the eye. The presence of retinal blur in the image formed on the retina can provide cues for accommodation, and the relative location of the image on the retina can provide cues for convergence-divergence movement. The cues for accommodation produce accommodation, resulting in the lens of the eye taking on a specific accommodative state in which a focused image of the object is formed on the retina of the eye (e.g., the fovea). On the other hand, the cues for convergence-divergence movement produce convergence-divergence movement (rotation of the eye) so that the image formed on each retina of each eye is at the corresponding retinal point that maintains monobiocular vision. At these positions, the eye can be said to be in a specific convergence-divergence state. Continuing to refer to Figure 4A, accommodation can be understood as the process by which the eye achieves a specific state of accommodation, and convergence / divergence can be understood as the process by which the eye achieves a specific state of convergence / divergence. As shown in Figure 4A, the state of accommodation and convergence / divergence of the eye can change when the user fixates on a different object. For example, the accommodated state can change when the user fixates on a new object at a different depth on the z-axis.

[0159] Although not limited by theory, it is thought that a viewer of an object may perceive the object as "three-dimensional" due to a combination of convergence / divergence motion and depth adjustment. As described above, the convergence / divergence movement of the two eyes relative to each other (e.g., the rotation of the eyes such that the pupils move towards each other or away from each other, converging the lines of sight of the eyes and fixing on an object) is closely associated with the depth adjustment of the eye's lens. Under normal conditions, a change in the focus of the eye's lens to change the focus from one object to another object at a different distance will automatically cause a corresponding change in the convergence / divergence motion to the same distance under a relationship known as the "depth adjustment - convergence / divergence reflex". Similarly, a change in the convergence / divergence motion will induce a corresponding change in the shape of the lens under normal conditions.

[0160] Referring now to FIG. 4B, an example of different depth adjustment and convergence / divergence motion states of the eyes is illustrated. The pair of eyes 222a fixates on an object at optical infinity, while the pair of eyes 222b fixates on an object 221 at less than optical infinity. It should be noted that the convergence / divergence motion states of each pair of eyes are different, with the pair of eyes 222a being directed straight, while the pair of eyes 222 converges on the object 221. The depth adjustment states of the eyes forming each pair of eyes 222a and 222b are also different, as represented by the different shapes of the lenses 210a, 220a.

[0161] Unfortunately, many users of conventional "3-D" display systems find such systems uncomfortable or completely fail to perceive depth due to the mismatch between the accommodation and convergence / divergence states in these displays. As described above, many stereoscopic or "3-D" display systems display scenes by providing each eye with slightly different images. Such systems are uncomfortable for many viewers because they, among other things, simply provide different presentations of scenes and cause changes in the convergence / divergence states of the eyes, but without corresponding changes in the accommodation states of those eyes. Rather, the images are presented by the display at a fixed distance from the eyes so that the eyes perceive all image information in a single accommodation state. Such arrangements go against the "accommodation-convergence / divergence reflex" by causing changes in the convergence / divergence state without corresponding changes in the accommodation state. This mismatch is thought to cause viewer discomfort. A display system that provides better integration between distance accommodation and convergence / divergence motion can create a more realistic and comfortable simulation of three-dimensional images.

[0162] While not limited by theory, the human eye is typically thought to be capable of interpreting a finite number of depth planes and providing depth perception. Consequently, a highly realistic simulation of perceived depth can be achieved by providing the eye with different presentations of images corresponding to each of these limited number of depth planes. In some embodiments, the different presentations may provide both cues for convergence-divergence movements and matching cues for accommodation, thereby providing physiologically correct accommodation-convergence-divergence movement matching.

[0163] Continuing with Figure 4B, two depth planes 240 are illustrated, corresponding to different spatial distances from eyes 210 and 220. With respect to a given depth plane 240, condensation-divergence motion cues may be provided by displaying appropriately different viewpoint images for each eye 210 and 220. In addition, with respect to a given depth plane 240, the light forming the image provided to each eye 210 and 220 may have wavefront divergence corresponding to a light field generated by a point at a distance in that depth plane 240.

[0164] In the illustrated embodiment, the distance along the z-axis of the depth plane 240 containing point 221 is 1 m. As used herein, the distance along the z-axis, or depth, may be measured using a zero point located at the exit pupil of the user's eye. Thus, the depth plane 240 located at a depth of 1 m corresponds to a distance of 1 m from the exit pupil of the user's eye on the optical axis of those eyes when the eyes are pointed toward optical infinity. As an approximation, the depth or distance along the z-axis may be measured from the display in front of the user's eye (e.g., the surface of a waveguide) and a value relating to the distance between the device and the exit pupil of the user's eye may be added. This value is called the pupil distance and may correspond to the distance between the exit pupil of the user's eye and the display worn by the user in front of the eye. In practice, the value relating to the pupil distance may generally be a normalized value used for all spectators. For example, the pupil distance may be assumed to be 20 mm, and the depth plane at a depth of 1 m may be at a distance of 980 mm from the front of the display.

[0165] Referring here to Figures 4C and 4D, embodiments of aligned accommodation-convergence-divergence distance and misaligned accommodation-convergence-divergence distance are illustrated, respectively. As shown in Figure 4C, the display system may provide images of virtual objects to each eye 210, 220. The images can cause the eyes 210, 220 to assume a convergence-divergence state in which the eyes converge on point 15 on the depth plane 240. In addition, the images may be formed by light having a wavefront curvature corresponding to a real object in its depth plane 240. As a result, the eyes 210, 220 assume an accommodation state in which the image is focused on the retina of their eyes. Thus, the user can perceive the virtual object as being at point 15 on the depth plane 240.

[0166] It should be understood that the accommodation and convergence / divergence states of eyes 210 and 220 are each associated with a specific distance on the z-axis. For example, an object at a specific distance from eyes 210 and 220 will cause those eyes to assume a specific accommodation state based on the distance of the object. The distance associated with a specific accommodation state is the accommodation distance A. d It can be called a specific convergence-divergence distance V associated with the eyes in a specific convergence-divergence state or relative position. d However, such a scenario exists. When the distance of accommodation and the distance of convergence and divergence are consistent, the relationship between accommodation and convergence / divergence can be considered physiologically correct. This is considered the most comfortable scenario for the viewer.

[0167] However, in stereoscopic displays, the accommodation distance and the convergence / divergence distance may not always be consistent. For example, as illustrated in Figure 4D, the images displayed to eyes 210 and 220 may be displayed with wavefront divergence corresponding to the depth plane 240, and eyes 210 and 220 may take on a specific accommodation state in which points 15a and 15b on their depth plane are in focus. However, the images displayed to eyes 210 and 220 may provide cues for convergence / divergence movements that cause eyes 210 and 220 to converge on point 15, which is not located on the depth plane 240. As a result, in some embodiments, the accommodation distance corresponds to the distance from the exit pupils of eyes 210 and 220 to the depth plane 240, while the convergence / divergence distance corresponds to a larger distance from the exit pupils of eyes 210 and 220 to point 15. The accommodation distance is different from the convergence / divergence distance. As a result, there is a mismatch in accommodation-convergence / divergence motion. Such mismatches are considered undesirable and can cause discomfort to the user. The mismatch is due to distance (e.g., V d -A d Please understand that this corresponds to and can be characterized using diopters.

[0168] It should be understood that in some embodiments, as long as the same reference point is used for the near-to-near-to-far accommodation distance and the convergence-divergence distance, reference points other than the exit pupils of eyes 210, 220 may be used to determine the distance for determining the near-to-near-to-far accommodation-to-convergence-divergence mismatch. For example, the distance may be measured from the cornea to the depth plane, from the retina to the depth plane, from the eyepiece (e.g., the waveguide of a display device) to the depth plane, etc.

[0169] While not limited by theory, it is conceivable that users may still perceive accommodation-convergence-divergence mismatches of up to approximately 0.25 diopters, up to approximately 0.33 diopters, and up to approximately 0.5 diopters as physiologically correct, even if the mismatch itself does not cause significant discomfort. In some embodiments, the display systems disclosed herein (e.g., display system 250, Figure 6) present to the viewer an image having accommodation-convergence-divergence mismatch of about 0.5 diopters or less. In some other embodiments, the accommodation-convergence-divergence mismatch of the image provided by the display system is about 0.33 diopters or less. In yet more embodiments, the accommodation-convergence-divergence mismatch of the image provided by the display system is about 0.25 diopters or less, including about 0.1 diopters or less.

[0170] Figure 5 illustrates aspects of an approach to simulating a three-dimensional image by correcting wavefront divergence. The display system includes a waveguide 270 configured to receive light 770 encoded with image information and output that light to the user's eye 210. The waveguide 270 may output light 650 with a defined amount of wavefront divergence corresponding to the wavefront divergence of the light field generated by a point on a desired depth plane 240. In some embodiments, the same amount of wavefront divergence is provided for all objects presented on that depth plane. In addition, the user's other eye may be shown to be provided with image information from a similar waveguide.

[0171] In some embodiments, a single waveguide may be configured to output light with a set wavefront divergence corresponding to one or a limited number of depth planes, and / or the waveguide may be configured to output light with a limited range of wavelengths. As a result, in some embodiments, multiple or stacked waveguides may be used to provide different wavefront divergences for different depth planes, and / or to output light with different ranges of wavelengths. It should be understood that, as used herein, a depth plane can be a plane or can follow the contour of a curved surface.

[0172] Figure 6 illustrates an embodiment of a waveguide stack for outputting image information to a user. The display system 250 includes a waveguide stack or stacked waveguide assembly 260, which may be used to provide three-dimensional perception to the eye / brain using a plurality of waveguides 270, 280, 290, 300, 310. It should be understood that the display system 250 may be considered a light field display in some embodiments. In addition, the waveguide assembly 260 may also be referred to as an eyepiece.

[0173] In some embodiments, the display system 250 may be configured to provide substantially continuous cues for convergence-divergence motion and a plurality of discrete cues for near accommodation. Cues for convergence-divergence motion may be provided by displaying different images to each of the user's eyes, and cues for near accommodation may be provided by outputting light that forms an image with a selectable discrete amount of wavefront divergence. In other words, the display system 250 may be configured to output light with a variable level of wavefront divergence. In some embodiments, each discrete level of wavefront divergence corresponds to a specific depth plane and may be provided by a particular one of waveguides 270, 280, 290, 300, and 310.

[0174] Continuing to refer to Figure 6, the waveguide assembly 260 may also include several features 320, 330, 340, 350 between the waveguides. In some embodiments, features 320, 330, 340, 350 may be one or more lenses. Waveguides 270, 280, 290, 300, 310 and / or Multiple lenses 320, 330, 340, and 350 may be configured to transmit image information to the eye using various levels of wavefront curvature or ray divergence. Each waveguide level may be associated with a specific depth plane and configured to output image information corresponding to that depth plane. Image input devices 360, 370, 380, 390, and 400 may function as light sources for the waveguides and may be used to input image information into the waveguides 270, 280, 290, 300, and 310, each configured to disperse incident light across each individual waveguide for output toward the eye 210, as described herein. Light exits from the output surfaces 410, 420, 430, 440, and 450 of the image input devices 360, 370, 380, 390, and 400 and is fed into the corresponding input surfaces 460, 470, 480, 490, and 500 of the waveguides 270, 280, 290, 300, and 310. In some embodiments, the input surfaces 460, 470, 480, 490, and 500 may each be the edge of the corresponding waveguide or a portion of the main surface of the corresponding waveguide (i.e., one of the waveguide surfaces that directly faces the world 510 or the viewer's eye 210). In some embodiments, a single beam of light (e.g., a collimated beam) may be fed into each waveguide and output the entire field of a cloned collimated beam that is directed toward the eye 210 at a specific angle (and divergence) corresponding to a depth plane associated with a particular waveguide. In some embodiments, one of the image input devices 360, 370, 380, 390, 400 may be associated with a plurality (e.g., three) of waveguides 270, 280, 290, 300, 310 into which light may be injected.

[0175] In some embodiments, the image input devices 360, 370, 380, 390, and 400 are discrete displays that each generate image information for input into the corresponding waveguides 270, 280, 290, 300, and 310, respectively. In some other embodiments, the image input devices 360, 370, 380, 390, and 400 are output terminals of a single multiplexed display that can send image information to each of the image input devices 360, 370, 380, 390, and 400, for example, via one or more optical conduits (such as optical fiber cables). It should be understood that the image information provided by the image input devices 360, 370, 380, 390, and 400 may include light of different wavelengths or colors (e.g., different primary colors, as discussed herein).

[0176] In some embodiments, the light introduced into waveguides 270, 280, 290, 300, and 310 is provided by an optical projection system 520, which comprises an optical module 530, which may include an optical emitter such as a light-emitting diode (LED). The light from the optical module 530 may be directed and modified via a beam splitter 550 by an optical modulator 540, such as a spatial light modulator. The optical modulator 540 may be configured to change the perceived intensity of the light introduced into waveguides 270, 280, 290, 300, and 310, thereby encoding the light with image information. Embodiments of the spatial light modulator include liquid crystal displays (LCDs), including liquid crystal on silicon (LCOS) displays. In some other embodiments, the spatial light modulator may be a MEMS device such as a digital light processing (DLP) device. Image input devices 360, 370, 380, 390, and 400 are graphically illustrated, and it should be understood that in some embodiments, these image input devices may represent different optical paths and locations within a common projection system, configured to output light into associated waveguides 270, 280, 290, 300, and 310. In some embodiments, the waveguides of waveguide assembly 260 may function as ideal lenses, relaying the light input into the waveguides to the user's eye. In this concept, the object may be a spatial light modulator 540, and the image may be an image on the depth plane.

[0177] In some embodiments, the display system 250 may be a scanning fiber display comprising one or more scanning fibers configured to project light in various patterns (e.g., raster scanning, helical scanning, Lissajous patterns, etc.) into one or more waveguides 270, 280, 290, 300, 310, and ultimately to the viewer's eye 210. In some embodiments, the illustrated image input devices 360, 370, 380, 390, 400 may schematically represent a single scanning fiber or a bundle of scanning fibers configured to input light into one or more waveguides 270, 280, 290, 300, 310. In some other embodiments, the illustrated image input devices 360, 370, 380, 390, 400 may schematically represent a plurality of scanning fibers or a plurality of bundles of scanning fibers, each configured to input light into one of the associated waveguides 270, 280, 290, 300, 310. It should be understood that one or more optical fibers may be configured to transmit light from the optical module 530 to one or more waveguides 270, 280, 290, 300, and 310. It should be understood that one or more intervening optical structures may be provided between the scanning fiber or multiple fibers and one or more waveguides 270, 280, 290, 300, and 310, for example, to redirect light emitted from the scanning fiber into one or more waveguides 270, 280, 290, 300, and 310.

[0178] The controller 560 controls the operation of one or more of the stacked waveguide assemblies 260, including the operation of the image input devices 360, 370, 380, 390, 400, the light source 530, and the optical module 540. In some embodiments, the controller 560 is part of the local data processing module 140. The controller 560 includes programming (e.g., instructions in a non-transient medium) to coordinate the timing and delivery of image information to the waveguides 270, 280, 290, 300, 310, for example, according to any of the various schemes disclosed herein. In some embodiments, the controller may be a single integrated device or a distributed system connected by wired or wireless communication channels. In some embodiments, the controller 560 may be part of the processing module 140 or 150 (Figure 9E).

[0179] Continuing with Figure 6, the waveguides 270, 280, 290, 300, and 310 may be configured to propagate light within each individual waveguide by total internal reflection (TIR). Each waveguide 270, 280, 290, 300, and 310 may be planar or have another shape (e.g., curved), with a main upper surface and a bottom surface and a rim extending between their main upper and bottom surfaces. In the illustrated configuration, each waveguide 270, 280, 290, 300, and 310 may include external coupling optical elements 570, 580, 590, 600, and 610, respectively, configured to extract light from the waveguide by redirecting the light propagating within each individual waveguide out of the waveguide and outputting image information to the eye 210. The extracted light may also be referred to as externally coupled light, and the external coupling optical elements may also be referred to as light extraction optical elements. The extracted beam of light can be output by the waveguide at the point where light propagating within the waveguide strikes the light extraction optical element. The external coupling optical elements 570, 580, 590, 600, 610 may be gratings, for example, including diffractive optical features as further discussed herein. For the sake of clarity and to facilitate the explanation, they are shown positioned on the bottom main surfaces of the waveguides 270, 280, 290, 300, 310, but in some embodiments, the external coupling optical elements 570, 580, 590, 600, 610 may be positioned on the top and / or bottom main surfaces, and / or directly within the volume of the waveguides 270, 280, 290, 300, 310, as further discussed herein. In some embodiments, the external coupling optical elements 570, 580, 590, 600, 610 may be mounted on a transparent substrate and formed within a layer of material that forms the waveguides 270, 280, 290, 300, 310. In some other embodiments, the waveguides 270, 280, 290, 300, 310 may be a monolithic piece of material, and the external coupling optical elements 570, 580, 590, 600, 610 may be formed on and / or inside the material piece.

[0180] Continuing with Figure 6, as discussed herein, each waveguide 270, 280, 290, 300, 310 is configured to emit light and form an image corresponding to a specific depth plane. For example, the waveguide 270 closest to the eye may be configured to deliver collimated light (injected into such waveguide 270) to the eye 210. The collimated light may represent the optical infinity focal plane. The next upper waveguide 280 may be configured to emit collimated light that passes through a first lens 350 (e.g., a negative lens) before reaching the eye 210. Such a first lens 350 may be configured to generate some convex wavefront curvature so that the eye / brain interprets the light originating from the next upper waveguide 280 as originating from a first focal plane closer inward from optical infinity toward the eye 210. Similarly, the third upper waveguide 290 passes its output light through both the first 350 and second 340 lenses before reaching the eye 210. The combined refractive power of the first 350 and second 340 lenses may be configured to produce a different, gradually increasing wavefront curvature so that the eye / brain interprets the light originating from the third waveguide 290 as originating from a second focal plane that is even closer inward toward the person from optical infinity than the light originating from the next upper waveguide 280.

[0181] Other waveguide layers 300, 310 and lenses 330, 320 are configured similarly, with the highest waveguide 310 in the stack emitting its output through all the lenses between it and the eye for a convergent focusing force representing the focal plane closest to the person. When viewing / interpreting light originating from the other side world 510 of the stacked waveguide assembly 260, a compensating lens layer 620 may be positioned on top of the stack to compensate for the convergent forces of the lower lens stacks 320, 330, 340, 350 to compensate for the stack of lenses 320, 330, 340, 350. Such a configuration provides the same number of perceived focal planes as there are available waveguide / lens pairs. Both the external coupling optical elements of the waveguides and the focusing sides of the lenses may be static (i.e., not dynamic or electroactive). In some alternative embodiments, one or both may be dynamic using electroactive features.

[0182] In some embodiments, two or more of the waveguides 270, 280, 290, 300, and 310 may have the same associated depth plane. For example, multiple waveguides 270, 280, 290, 300, and 310 may be configured to output images set in the same depth plane, or multiple subsets of waveguides 270, 280, 290, 300, and 310 may be configured to output images set in the same multiple depth planes, with one set for each depth plane. This may offer the advantage of forming tiled images that provide an extended field of view in those depth planes.

[0183] Continuing with Figure 6, the external coupling optical elements 570, 580, 590, 600, and 610 may be configured to redirect light from their individual waveguides for specific depth planes associated with the waveguides and to output the light with an appropriate amount of divergence or collimation. As a result, waveguides with different associated depth planes may have different configurations of the external coupling optical elements 570, 580, 590, 600, and 610, which output light with different amounts of divergence depending on the associated depth plane. In some embodiments, the light extraction optical elements 570, 580, 590, 600, and 610 may be three-dimensional or surface features that can be configured to output light at specific angles. For example, the light extraction optical elements 570, 580, 590, 600, and 610 may be three-dimensional holograms, surface holograms, and / or diffraction gratings. In some embodiments, features 320, 330, 340, and 350 may not be lenses. Rather, they may simply be spacers (e.g., cladding layers and / or structures for forming voids).

[0184] In some embodiments, the external coupling optical elements 570, 580, 590, 600, 610 are diffraction features or “diffractive optical elements” (also referred to herein as “DOEs”) that form a diffraction pattern. Preferably, the DOEs have sufficiently low diffraction efficiency so that only a portion of the beam light is deflected toward the eye 210 at each intersection of the DOEs, while the remainder continues to travel through the waveguide via TIR. The light carrying the image information is therefore split into several associated emission beams that exit the waveguide at various locations, resulting in a very uniform pattern of emission toward the eye 210 with respect to this particular collimated beam bouncing within the waveguide.

[0185] In some embodiments, one or more DOEs may be switchable between an "on" state in which they actively diffract and an "off" state in which they do not significantly diffract. For example, a switchable DOE may comprise a layer of polymer-dispersed liquid crystal in which microdroplets have a diffraction pattern in a host medium, and the refractive index of the microdroplets may be switched to substantially match the refractive index of the host material (in which case the pattern does not significantly diffract incident light), or the microdroplets may be switched to a refractive index that does not match that of the host medium (in which case the pattern actively diffracts incident light).

[0186] In some embodiments, a camera assembly 630 (e.g., a digital camera including visible light and infrared light cameras) may be provided to capture images of the eye 210 and / or the surrounding tissues, for example, to detect user input and / or monitor the user's physiological state. As used herein, the camera may be any image-capturing device. In some embodiments, the camera assembly 630 may include the image-capturing device and a light source that projects light (e.g., infrared light) onto the eye, and the light is then reflected by the eye and can be detected by the image-capturing device. In some embodiments, the camera assembly 630 may be mounted on a frame or support structure 80 (Figure 9E) and may communicate with processing modules 140 and / or 150 that can process image information from the camera assembly 630. In some embodiments, one camera assembly 630 may be used per eye to monitor each eye separately.

[0187] In some embodiments, the camera assembly 630 may observe user movements, such as eye movements. For example, the camera assembly 630 may capture an image of the eye 210 and determine the size, position, and / or orientation of the pupil (or other structure of the eye 210). The camera assembly 630 may, if desired, acquire an image (processed by a processing network of the type described herein) used to determine the direction the user is looking (e.g., eye posture or gaze direction). In some embodiments, the camera assembly 630 may include multiple cameras, at least one of which may be used for each eye and independently determine the eye posture or gaze direction of each eye separately. In some embodiments, the camera assembly 630 may, in combination with a processing network such as a controller 560 or a local data processing module 140, determine the eye posture or gaze direction based on a flash (e.g., reflection) of light (e.g., infrared light) reflected from a light source contained within the camera assembly 630.

[0188] Referring here to Figure 7, an embodiment of an outgoing beam output by a waveguide is shown. Although one waveguide is illustrated, other waveguides in the waveguide assembly 260 (Figure 6) may function similarly, and it should be understood that the waveguide assembly 260 includes multiple waveguides. Light 640 is introduced into the waveguide 270 at the input surface 460 of the waveguide 270 and propagates through the waveguide 270 by TIR. At the point where the light 640 collides on the DOE 570, a portion of the light exits the waveguide as an outgoing beam 650. The outgoing beam 650 is illustrated as substantially parallel, but may be redirected to propagate to the eye 210 at a certain angle (e.g., forming a divergent outgoing beam), depending on the depth plane associated with the waveguide 270, as discussed herein. It should be understood that a nearly parallel emitted beam may represent a waveguide with an externally coupled optical element that externally couples the light to form an image that appears to be set in the depth plane at a distance from the eye 210 (e.g., optical infinity). Other waveguides or other sets of externally coupled optical elements may output a more divergent emitted beam pattern, which would require the eye 210 to adjust to a closer distance and focus onto the retina, and would be interpreted by the brain as light from a distance closer to the eye 210 than optical infinity.

[0189] In some embodiments, a full-color image may be formed in each depth plane by overlaying an image onto each of primary colors, for example, three or more primary colors. Figure 8 illustrates an embodiment of a stacked waveguide assembly, where each depth plane includes an image formed using several different primary colors. The illustrated embodiment shows depth planes 240a–240f, but more or fewer depths may also be considered. Each depth plane may have three or more associated primary color images, including a first image of a first color G, a second image of a second color R, and a third image of a third color B. Different depth planes are indicated in the figure by different numbers relating to diopters (dpt) following the letters G, R, and B. As merely an embodiment, the numbers following each of these letters indicate diopters (1 / m), i.e., the inverse distance of the depth plane from the viewer, and each box in the figure represents an individual primary color image. In some embodiments, the precise location of the depth plane for different primary colors may vary to account for differences in the focusing of light of different wavelengths in the eye. For example, different primary color images for a given depth plane may be placed on depth planes corresponding to different distances from the user. Such arrangements may increase visual acuity and user comfort and / or reduce chromatic aberration.

[0190] In some embodiments, each primary color light may be output by a single dedicated waveguide, and as a result, each depth plane may have multiple waveguides associated with it. In such embodiments, each box in the figure, including the letters G, R, or B, can be understood to represent an individual waveguide, and three waveguides may be provided for each depth plane, and three primary color images are provided for each depth plane. The waveguides associated with each depth plane are shown adjacent to each other in this drawing for ease of explanation, but it should be understood that in a physical device, all waveguides may be arranged in a stack with one waveguide per level. In some other embodiments, multiple primary colors may be output by the same waveguide, for example, so that only a single waveguide may be provided for each depth plane.

[0191] Continuing to refer to Figure 8, in some embodiments, G is green, R is red, and B is blue. In some other embodiments, other colors associated with other wavelengths of light, including magenta and cyan, may be used in addition to or replace one or more of red, green, or blue.

[0192] Throughout this disclosure, any reference to a given color of light should be understood as encompassing one or more wavelengths of light within a range of wavelengths that are perceived by the viewer as that given color. For example, red light may include one or more wavelengths of light in the range of approximately 620–780 nm, green light may include one or more wavelengths of light in the range of approximately 492–577 nm, and blue light may include one or more wavelengths of light in the range of approximately 435–493 nm.

[0193] In some embodiments, the light source 530 (Figure 6) may be configured to emit light of one or more wavelengths outside the viewer's visual perception range, such as infrared and / or ultraviolet wavelengths. In addition, internal coupling, external coupling, and other light redirection structures of the waveguide of the display 250 may be configured to direct and emit this light from the display toward the user's eye 210, for example, for imaging and / or user stimulation applications.

[0194] Referring here to Figure 9A, in some embodiments, light impacting a waveguide may need to be redirected to internally couple that light into the waveguide. Internal coupling optical elements may be used to redirect and internally couple the light into its corresponding waveguide. Figure 9A illustrates cross-sectional side views of embodiments of multiple or set 660 stacked waveguides, each including an internal coupling optical element. Each waveguide may be configured to output light of one or more different wavelengths or one or more different wavelength ranges. Stack 660 may correspond to stack 260 (Figure 6), and the illustrated waveguides of stack 660 may correspond to a portion of multiple waveguides 270, 280, 290, 300, 310, but it should be understood that light from one or more of the image input devices 360, 370, 380, 390, 400 is input into the waveguide from a position where the light is required to be redirected for internal coupling.

[0195] The illustrated set of stacked waveguides 660 includes waveguides 670, 680, and 690. Each waveguide includes associated internal coupling optical elements (which may also be referred to as optical input areas on the waveguide), for example, internal coupling optical element 700 is located on the main surface of waveguide 670 (e.g., the upper main surface), internal coupling optical element 710 is located on the main surface of waveguide 680 (e.g., the upper main surface), and internal coupling optical element 720 is located on the main surface of waveguide 690 (e.g., the upper main surface). In some embodiments, one or more of the internal coupling optical elements 700, 710, and 720 may be located on the bottom main surfaces of individual waveguides 670, 680, and 690 (in particular, one or more internal coupling optical elements are reflective deflection optical elements). As illustrated, the internally coupled optical elements 700, 710, and 720 may be located on the upper main surface of their respective waveguides 670, 680, and 690 (or on the upper part of the following lower waveguide), and in particular, these internally coupled optical elements are transmissive deflection optical elements. In some embodiments, the internally coupled optical elements 700, 710, and 720 may be located within the body of the respective waveguides 670, 680, and 690. In some embodiments, as discussed herein, the internally coupled optical elements 700, 710, and 720 are wavelength-selective, selectively redirecting one or more wavelengths of light while transmitting other wavelengths of light. Although illustrated on one side or corner of their respective waveguides 670, 680, and 690, it should be understood that in some embodiments, the internally coupled optical elements 700, 710, and 720 may be located within other areas of their respective waveguides 670, 680, and 690.

[0196] As illustrated, the internally coupled optical elements 700, 710, and 720 may be offset laterally from each other in the direction of light propagating to these internally coupled optical elements, as seen in the illustrated front view. In some embodiments, each internally coupled optical element may be offset so that its light does not pass through another internally coupled optical element. For example, each internally coupled optical element 700, 710, and 720 may be configured to receive light from different image input devices 360, 370, 380, 390, and 400, as shown in Figure 6, and may be separated from other internally coupled optical elements 700, 710, and 720 (e.g., separated laterally) so that it substantially does not receive light from the other internally coupled optical elements 700, 710, and 720.

[0197] Each waveguide also includes associated optical dispersion elements, for example, optical dispersion element 730 is located on the main surface (e.g., upper main surface) of waveguide 670, optical dispersion element 740 is located on the main surface (e.g., upper main surface) of waveguide 680, and optical dispersion element 750 is located on the main surface (e.g., upper main surface) of waveguide 690. In some other embodiments, optical dispersion elements 730, 740, and 750 may be located on the bottom main surfaces of the associated waveguides 670, 680, and 690, respectively. In some other embodiments, optical dispersion elements 730, 740, and 750 may be located on both the top and bottom main surfaces of the associated waveguides 670, 680, and 690, respectively, or optical dispersion elements 730, 740, and 750 may be located on different top and bottom main surfaces within different associated waveguides 670, 680, and 690, respectively.

[0198] Waveguides 670, 680, and 690 may be separated and isolated by, for example, gaseous, liquid, and / or solid layers of material. For example, as shown, layer 760a may separate waveguides 670 and 680, and layer 760b may separate waveguides 680 and 690. In some embodiments, layers 760a and 760b are formed from a low refractive index material (i.e., a material having a lower refractive index than the material forming the immediate vicinity of waveguides 670, 680, and 690). Preferably, the refractive index of the material forming layers 760a and 760b is 0.05 or more and 0.10 or less than the refractive index of the material forming waveguides 670, 680, and 690. Advantageously, the lower refractive index layers 760a, 760b may function as cladding layers that promote total internal reflection (TIR) ​​of light through the waveguides 670, 680, 690 (e.g., TIR between the upper and lower main surfaces of each waveguide). In some embodiments, layers 760a, 760b are formed from air. It should be understood that, although not shown, the upper and lower parts of the illustrated set 660 waveguides may also include an immediate cladding layer.

[0199] Preferably, to facilitate manufacturing and other considerations, the materials forming waveguides 670, 680, and 690 are similar or identical, and the materials forming layers 760a and 760b are similar or identical. In some embodiments, the materials forming waveguides 670, 680, and 690 may differ between one or more waveguides, and / or the materials forming layers 760a and 760b may differ, while still maintaining the various refractive index relationships described above.

[0200] Continuing to refer to Figure 9A, rays 770, 780, and 790 are incident on the waveguide set 660. It should be understood that rays 770, 780, and 790 may also be introduced into waveguides 670, 680, and 690 by one or more image input devices 360, 370, 380, 390, and 400 (Figure 6).

[0201] In some embodiments, the rays 770, 780, and 790 may have different properties, such as different wavelengths or different wavelength ranges, which may correspond to different colors. The internal coupling optical elements 700, 710, and 720 each deflect the incident light so that the light propagates through one of the waveguides 670, 680, and 690 by TIR. In some embodiments, the internal coupling optical elements 700, 710, and 720 each selectively deflect one or more specific wavelengths of light while allowing other wavelengths to pass through the lower waveguide and associated internal coupling optical elements.

[0202] For example, the internally coupled optical element 700 may be configured to transmit rays 780 and 790 having different second and third wavelengths or wavelength ranges, while deflecting a ray 770 having a first wavelength or wavelength range. The transmitted ray 780 collides with an internally coupled optical element 710 configured to deflect light of the second wavelength or wavelength range, and is thereby deflected. The ray 790 is deflected by an internally coupled optical element 720 configured to selectively deflect light of a third wavelength or wavelength range.

[0203] Continuing with Figure 9A, the deflected rays 770, 780, and 790 are deflected so that they propagate through the corresponding waveguides 670, 680, and 690. That is, the internal coupling optical elements 700, 710, and 720 of each waveguide deflect the light into its corresponding waveguide 670, 680, and 690, and internally couple the light into the corresponding waveguide. The rays 770, 780, and 790 are deflected at an angle that causes the light to propagate through the individual waveguides 670, 680, and 690 by TIR. The rays 770, 780, and 790 propagate through the individual waveguides 670, 680, and 690 by TIR until they collide with the corresponding optical dispersion elements 730, 740, and 750 of the waveguide.

[0204] Referring now to Figure 9B, a perspective view of an embodiment of the multiple stacked waveguides shown in Figure 9A is illustrated. As described above, the internally coupled rays 770, 780, and 790 are deflected by the internally coupled optical elements 700, 710, and 720, respectively, and then propagate by TIR within waveguides 670, 680, and 690, respectively. The rays 770, 780, and 790 then collide with the optical dispersion elements 730, 740, and 750, respectively. The optical dispersion elements 730, 740, and 750 deflect the rays 770, 780, and 790 so that they propagate toward the externally coupled optical elements 800, 810, and 820, respectively.

[0205] In some embodiments, the light dispersion elements 730, 740, and 750 are orthogonal pupil expanders (OPEs). In some embodiments, the OPEs deflect or disperse light to the external coupling optical elements 800, 810, and 820, and in some embodiments, they can also increase the beam or spot size of the light as it propagates to the external coupling optical elements. In some embodiments, the light dispersion elements 730, 740, and 750 may be omitted, and the internal coupling optical elements 700, 710, and 720 may be configured to deflect light directly to the external coupling optical elements 800, 810, and 820. For example, referring to Figure 9A, the light dispersion elements 730, 740, and 750 may be replaced by the external coupling optical elements 800, 810, and 820, respectively. In some embodiments, the external coupling optical elements 800, 810, 820 are exit pupils (EPs) or exit pupil expanders (EPEs) that direct light towards the viewer's eye 210 (Figure 7). It should be understood that the OPEs may be configured to increase the dimensions of the eyebox along at least one axis, and the EPEs may increase the eyebox along axes that intersect with the axes of the OPEs, for example, orthogonal axes. For example, each OPE may be configured to redirect a portion of the light impacting the OPE to an EPE in the same waveguide, while allowing the rest of the light to continue propagating along the waveguide. In response to the impact on the OPE, another portion of the remaining light is again redirected to the EPE, and the rest of that portion continues to propagate further along the waveguide, etc. Similarly, in response to the impact on the EPE, a portion of the impacting light is directed out of the waveguide towards the user, and the rest of that light continues to propagate through the waveguide until it impacts the EP again, at which point another portion of the impacting light is directed out of the waveguide, and so on. As a result, the single beam of internally coupled light is "duplicated" each time a portion of its light is redirected by the OPE or EPE, thereby forming a cloned beam field of light, as shown in Figure 6. In some embodiments, the OPE and / or EPE may be configured to modify the size of the light beam.

[0206] Therefore, referring to Figures 9A and 9B, in some embodiments, the set of waveguides 660 includes, for each primary color, waveguides 670, 680, 690, internally coupled optical elements 700, 710, 720, optical dispersion elements (e.g., OPE) 730, 740, 750, and externally coupled optical elements (e.g., EP) 800, 810, 820. Waveguides 670, 680, 690 may be stacked with air gaps / cladding layers between each one. The internally coupled optical elements 700, 710, 720 redirect or deflect the incident light into their waveguides (using different internally coupled optical elements that receive light of different wavelengths). The light then propagates within the individual waveguides 670, 680, 690 at angles that will result in a TIR. In the embodiment shown, a ray 770 (e.g., blue light) is polarized by the first internal coupling optical element 700 in the manner described above, and then continues to bounce along the waveguide, interacting with the optical dispersion element (e.g., OPE) 730 and then the external coupling optical element (e.g., EP) 800. Rays 780 and 790 (e.g., green and red light, respectively) pass through waveguide 670, with ray 780 colliding with the internal coupling optical element 710, thereby being deflected. Ray 780 will then bounce along waveguide 680 via TIR, proceeding to its optical dispersion element (e.g., OPE) 740 and then the external coupling optical element (e.g., EP) 810. Finally, ray 790 (e.g., red light) passes through waveguide 690 and colliding with the optical internal coupling optical element 720 of waveguide 690. The internal optical coupling element 720 deflects the ray 790 so that it propagates by TIR to the optical dispersion element (e.g., OPE) 750, and then by TIR to the external coupling optical element (e.g., EP) 820. The external coupling optical element 820 then finally externally couples the ray 790 to the viewer, who also receives externally coupled light from the other waveguides 670, 680.

[0207] Figure 9C illustrates upper and lower plan views of the embodiment of the multiple stacked waveguides shown in Figures 9A and 9B. These upper and lower views may also be referred to as front views, as they are seen in the direction of light propagation toward the internal coupling optical elements 800, 810, and 820; that is, the upper and lower views should be understood as diagrams of waveguides in which image light is incident normal to the page. As shown, waveguides 670, 680, and 690 may be vertically aligned with their associated optical dispersion elements 730, 740, and 750 and associated external coupling optical elements 800, 810, and 820. However, as discussed herein, the internal coupling optical elements 700, 710, and 720 are not vertically aligned. Rather, the internal coupling optical elements are preferably non-overlapping (e.g., laterally spaced, as seen in the upper and lower views). As will be further discussed herein, the non-overlapping spatial array facilitates the ingress of light from different sources into different waveguides on a one-to-one basis, thereby enabling specific light sources to be uniquely coupled to specific waveguides. In some embodiments, arrays comprising non-overlapping, spatially separated internally coupled optical elements may be referred to as pupil-shifting systems, where the internally coupled optical elements in these arrays may correspond to subpupils.

[0208] It should be understood that spatially overlapping areas, as seen in the figures above and below, may have lateral overlap of 70% or more, 80% or more, or 90% or more of their area. On the other hand, laterally shifted areas, as seen in the figures above and below, may have overlap of less than 30%, less than 20%, or less than 10% of their area. In some embodiments, laterally shifted areas have no overlap.

[0209] Figure 9D illustrates top and bottom plan views of another embodiment of multiple stacked waveguides. As shown, waveguides 670, 680, and 690 may be vertically aligned. However, compared to the configuration in Figure 9C, the separate optical dispersion elements 730, 740, and 750 and their associated external coupling optical elements 800, 810, and 820 are omitted. Instead, the optical dispersion elements and external coupling optical elements are effectively superimposed and occupy the same area, as seen in the top and bottom figures. In some embodiments, the optical dispersion elements (e.g., OPEs) may be located on one main surface of waveguides 670, 680, and 690, and the external coupling optical elements (e.g., EPEs) may be located on other main surfaces of those waveguides. Thus, each waveguide 670, 680, and 690 may collectively have superimposed optical dispersion and external coupling optical elements, referred to as combined OPEs / EPEs 1281, 1282, and 1283, respectively. Further details regarding such combined OPE / EPEs can be found in U.S. Patent Application No. 16 / 221,359, filed December 14, 2018 (the entire disclosure of which is incorporated herein by reference). The internally coupled optical elements 700, 710, and 720 internally couple light and direct it to the combined OPE / EPEs 1281, 1282, and 1283, respectively. In some embodiments, as illustrated, the internally coupled optical elements 700, 710, and 720 may be laterally offset if they have an offset pupil spatial array (for example, they are laterally spaced apart as seen in the illustrated upper and lower figures). Similar to the configuration in Figure 9C, this laterally offset spatial array facilitates the injection of light of different wavelengths into different waveguides on a one-to-one basis (for example, from different light sources).

[0210] Figure 9E illustrates an embodiment of a wearable display system 60 in which various waveguides and associated systems disclosed herein may be integrated. In some embodiments, the display system 60 is the system 250 of Figure 6, which graphically illustrates some parts of the system 60 in more detail. For example, the waveguide assembly 260 of Figure 6 may be part of the display 70.

[0211] Continuing with reference to Figure 9E, the display system 60 includes a display 70 and various mechanical and electronic modules and systems to support the functions of the display 70. The display 70 may be coupled to a frame 80, which is wearable by the display system user or viewer 90 and is configured to position the display 70 in front of the user 90's eyes. In some embodiments, the display 70 may be considered eyewear. The display 70 may include one or more waveguides, such as a waveguide 270, configured to relay internally coupled image light and output the image light to the user 90's eyes. In some embodiments, a speaker 100 is coupled to the frame 80 and configured to be positioned adjacent to the user 90's ear canal (in some embodiments, another speaker, not shown, may also be optionally positioned adjacent to the user's other ear canal to provide stereo / shapeable sound control). The display system 60 may also include one or more microphones 110 or other devices to detect sound. In some embodiments, the microphone may be configured to allow the user to provide input or commands to the system 60 (e.g., selection of voice menu commands, natural language questions, etc.) and / or enable audio communication with other persons (e.g., other users of a similar display system). The microphone may further be configured as a peripheral sensor to collect audio data (e.g., sounds from the user and / or the environment). In some embodiments, the display system 60 may further include one or more outward-facing environmental sensors 112 configured to detect objects, stimuli, people, animals, places, or other aspects of the world around the user. For example, the environmental sensors 112 may include one or more cameras which may be outward-facing and positioned to capture images similar to, for example, at least a portion of the user 90's normal field of view. In some embodiments, the display system may also include a peripheral sensor 120a which is separate from the frame 80 and may be mounted on the user 90's body (e.g., the user 90's head, torso, limbs, etc.).In some embodiments, the peripheral sensor 120a may be configured to obtain data characterizing the physiological state of the user 90. For example, the sensor 120a may be an electrode.

[0212] Continuing with Figure 9E, the display 70 is operably coupled to the local data processing module 140 by a communication link 130, such as a wired cable or wireless connectivity, which may be mounted in various configurations, such as being fixedly attached to the frame 80, fixedly attached to a helmet or hat worn by the user, built into headphones, or otherwise detachably attached to the user 90 (e.g., in a backpack configuration, in a belt-mounted configuration). Similarly, the sensor 120a may be operably coupled to the local data processing module 140 by a communication link 120b, such as a wired cable or wireless connectivity. The local processing and data module 140 may include a hardware processor and digital memory such as non-volatile memory (e.g., flash memory or a hard disk drive), both of which may be used to assist in data processing, caching, and storage. Optionally, the local processing and data module 140 may include one or more central processing units (CPUs), graphics processing units (GPUs), dedicated processing hardware, etc. The data may include a) data captured from sensors (image acquisition devices (such as cameras), microphones, inertial measurement units, accelerometers, compasses, GPS units, wireless devices, gyroscopes, and / or other sensors disclosed herein (e.g., operably coupled to frame 80 or otherwise attached to user 90)), and / or b) possibly data obtained and / or processed using the remote processing module 150 and / or remote data repository 160 (including data related to virtual content) for passage to the display 70 after processing or reading. The local processing and data module 140 may be operably coupled to the remote processing module 150 and the remote data repository 160 by communication links 170, 180 via wired or wireless communication links, etc., so that these remote modules 150, 160 are operably coupled to each other and available as resources for the local processing and data module 140.In some embodiments, the local processing and data module 140 may include one or more of the following: an image acquisition device, a microphone, an inertial measurement unit, an accelerometer, a compass, a GPS unit, a wireless device, and / or a gyroscope. In some other embodiments, one or more of these sensors may be mounted on the frame 80 or may be independent structures communicating with the local processing and data module 140 via a wired or wireless communication path.

[0213] Continuing with Figure 9E, in some embodiments, the remote processing module 150 may comprise one or more processors configured to analyze and process data and / or image information, including, for example, one or more central processing units (CPUs), graphics processing units (GPUs), dedicated processing hardware, etc. In some embodiments, the remote data repository 160 may comprise digital data storage equipment, which may be available through the Internet or other networking configurations in a “cloud” resource configuration. In some embodiments, the remote data repository 160 may comprise one or more remote servers, which provide information, for example, information for generating virtual content, to the local processing and data module 140 and / or the remote processing module 150. In some embodiments, all data is stored, and all calculations are performed in the local processing and data module, enabling fully autonomous use from the remote module. Optionally, an external system (e.g., one or more processors, one or more computer systems), including a CPU, GPU, etc., may perform at least part of the processing (e.g., generating image information, processing data) and provide information to modules 140, 150, and 160, and receive information from them, for example, via a wireless or wired connection.

[0214] Figure 10 illustrates an embodiment of a wearable display system comprising a light projection system 910 having a spatial light modulator 930 and a separate light source 940. The light source 940 may comprise one or more light emitters and illuminate the spatial light modulator (SLM) 930. A lens structure 960 may be used to focus the light from the light source 940 onto the SLM 930. A beam splitter (e.g., a polarizing beam splitter (PBS)) 950 reflects the light from the light source 940 onto the spatial light modulator 930, which reflects and modulates the light. The reflected, modulated light, also referred to as image light, then propagates through the beam splitter 950 to the eyepiece 920. Another lens structure, a projection optical system 970, may be used to focus or concentrate the image light onto the eyepiece 920. The eyepiece 920 may include one or more waveguides or waveguides that relay the modulated light to the eye 210.

[0215] As described herein, the separate light source 940 and associated lens structure 960 may, undesirably, add weight and size to the wearable display system. This can reduce the comfort of the display system, especially for users who wear the display system for extended periods.

[0216] In addition, the light source 940, in conjunction with the SLM 930, can consume energy inefficiently. For example, the light source 940 can illuminate the entire SLM 930. The SLM 930 then selectively reflects the light toward the eyepiece 920. Therefore, not all of the light produced by the light source 940 can be used to form an image. A portion of the light, for example, the light corresponding to dark areas of the image, is not reflected toward the eyepiece 920. As a result, the light source 940 uses the energy to produce light to illuminate the entire SLM 930, but only a certain proportion of the light may be needed to form some images.

[0217] Furthermore, as described herein, in some cases, the SLM930 may modulate light and selectively reflect incident light using micromirrors or liquid crystal molecules to correct the amount of light reflected from the lower layer mirrors. As a result, such a device requires the physical movement of optical elements (e.g., micromirrors or liquid crystal molecules in an LCoS or DLP panel, respectively) to modulate light from the light source 940. The physical movement required to modulate light and encode it with image information, for example, corresponding to pixels, may occur relatively slowly compared to, for example, the ability to turn an LED or OLED "on" or "off". This relatively slow movement may limit the frame rate of the display system and may be visible as, for example, motion blur, color breakage, and / or inconsistency with the user's head posture or changes in such posture in the presented image.

[0218] Advantageously, wearable displays utilizing light-emitting microdisplays as disclosed herein can facilitate wearable display systems with relatively low weight and bulk, high energy efficiency, and high frame rates, resulting in low motion blur and short latency from motion to image rendering. Low blur and short latency from motion to image rendering are further discussed in U.S. Provisional Application No. 62 / 786199, filed December 28, 2018 (the entire disclosure of which is incorporated herein by reference). In addition, compared to scanning fiber displays, light-emitting microdisplays can avoid artifacts caused by the use of coherent light sources.

[0219] Referring here to Figure 11A, an embodiment of a wearable display system is illustrated, comprising a light projection system 1010 having a plurality of light-emitting microdisplays 1030a, 1030b, and 1030c. Light from the microdisplays 1030a, 1030b, and 1030c is combined by an optical combiner 1050 and directed toward an eyepiece 1020, which relays the light to the user's eye 210. A projection optical system 1070 may be provided between the optical combiner 1050 and the eyepiece 1020. In some embodiments, the eyepiece 1020 may be a waveguide assembly comprising one or more waveguides. In some embodiments, the light projection system 1010 and the eyepiece 1020 may be supported (e.g., mounted) on a frame 80 (Figure 9E).

[0220] In some embodiments, the microdisplays 1030a, 1030b, and 1030c may be monochrome microdisplays, each monochrome microdisplay emitting light of a different primary color to provide a monochrome image. As discussed herein, the monochrome images are combined to form a full-color image.

[0221] In some other embodiments, the microdisplays 1030a, 1030b, and 1030c may each be full-color displays configured to output light of all primary colors. For example, the microdisplays 1030a, 1030b, and 1030c each include red, green, and blue light emitters. The microdisplays 1030a, 1030b, and 1030c may be the same and may display the same image. However, utilizing multiple microdisplays may offer the advantage of increasing the brightness and brightness dynamic range of the image by combining the light from the multiple microdisplays to form a single image. In some embodiments, two or more (e.g., three) microdisplays may be used, and the optical combiner 1050 is configured to combine the light from all of these microdisplays.

[0222] A microdisplay may comprise an array of photoemitters. Examples of photoemitters include organic light-emitting diodes (OLEDs) and microlight-emitting diodes (microLEDs). It should be understood that OLEDs utilize organic materials to emit light, while microLEDs utilize inorganic materials to emit light. Advantageously, some microLEDs offer higher brightness and higher efficiency (in terms of lux / W) than OLEDs. In some embodiments, the microdisplay is preferably a microLED display.

[0223] Continuing with Figure 11A, the microdisplays 1030a, 1030b, and 1030c may be configured to emit image light 1032a, 1032b, and 1032c, respectively. If the microdisplays are monochrome microdisplays, the image light 1032a, 1032b, and 1032c may each be different primary colors. The optical combiner 1050 receives the image light 1032a, 1032b, and 1032c and effectively combines the light so that it propagates generally in the same direction, for example toward the projection optical system 1070. In some embodiments, the optical combiner 1050 may be a dichroic X-cube prism having a reflective inner surface that redirects the image light 1032a, 1032b, and 1032c toward the projection optical system 1070. It should be understood that the projection optical system 1070 may be a lens structure comprising one or more lenses that converge or focus the image light onto the eyepiece 1020. The eyepiece 1020 then relays the image light 1032a, 1032b, and 1032c to the eye 210.

[0224] In some embodiments, the eyepiece 1020 may comprise a plurality of stacked waveguides 1020a, 1020b, 1020c, each having a separate internally coupled optical element 1022a, 1022b, 1022c. In some embodiments, the number of waveguides is proportional to the number of primary colors provided by the microdisplays 1030a, 1030b, 1030c. For example, if there are three primary colors, the number of waveguides in the eyepiece 1020 may include a set of three waveguides or multiple sets of three waveguides each. In some embodiments, each set may output light with wavefront divergence corresponding to a particular depth plane, as discussed herein. It should be understood that waveguides 1020a, 1020b, 1020c and internal coupling optical elements 1022a, 1022b, 1022c may correspond to waveguides 670, 680, 690 and internal coupling optical elements 700, 710, 720 in Figures 9A-9C, respectively. As can be seen from projection optical system 1070, internal coupling optical elements 1022a, 1022b, 1022c may be shifted laterally so that they do not overlap, at least partially, as seen in such figures.

[0225] As illustrated, various internal coupling optical elements disclosed herein (e.g., internal coupling optical elements 1022a, 1022b, 1022c) may be located on the main surface of the associated waveguide (e.g., waveguides 1020a, 1020b, 1020c, respectively). In addition, as also illustrated, the main surface on which a given internal coupling optical element is located may be the back surface of the waveguide. In such a configuration, the internal coupling optical element may be a reflective light redirection element, which internally couples light by reflecting light through the associated waveguide at an angle that supports TIR. In some other configurations, the internal coupling optical element may be located on the front surface of the waveguide (closer to the projection optical system 1070 than the back surface). In such a configuration, the internal coupling optical element may be a transmissive light redirection element, which internally couples light by changing the direction of light propagation as light is transmitted through the internal coupling optical element. It should be understood that any of the internally coupled optical elements disclosed herein may be reflective or transmissive internally coupled optical elements.

[0226] Continuing with Figure 11A, image light 1032a, 1032b, and 1032c from different microdisplays 1030a, 1030b, and 1030c may follow different paths to the eyepiece 1020 such that they collide with different internal coupling optical elements 1022a, 1022b, and 1022c. If the image light 1032a, 1032b, and 1032c contain light of different primary colors, the associated internal coupling optical elements 1022a, 1022b, and 1022c may each be configured to selectively internally couple light of different wavelengths, for example, as described above with respect to the internal coupling optical elements 700, 710, and 720 in Figures 9A-9C.

[0227] Continuing with Figure 11A, the optical combiner 1050 may be configured to redirect the image light 1032a, 1032b, 1032c emitted by the microdisplays 1030a, 1030b, 1032c so that the image light propagates along different optical paths to collide with the appropriate associated internal coupling optical elements 1022a, 1022b, 1022c. Thus, the optical combiner 1050 combines the image light 1032a, 1032b, 1032c in the sense that the image light is output from a common surface of the optical combiner 1050, but the light exits the optical combiner in slightly different directions. For example, the reflective internal surfaces 1052, 1054 of the X-cube prism may be angled to direct the image light 1032a, 1032b, 1032c along different paths to the eyepiece 1020, respectively. As a result, image light 1032a, 1032b, 1032c can be incident on different associated internal coupling optical elements 1022a, 1022b, 1022c. In some embodiments, microdisplays 1030a, 1030b, 1030c can be appropriately angled with respect to the reflective inner surfaces 1052, 1054 of the X-cube prism to provide a desired optical path to the internal coupling optical elements 1022a, 1022b, 1022c. For example, the surface of one or more of the microdisplays 1030a, 1030b, 1030c may be angled to match the surface of the optical combiner 1050 so that image light emitted by the microdisplay is incident on the reflective inner surfaces 1052, 1054 at an appropriate angle and propagates toward the associated internal coupling optical elements 1022a, 1022b, or 1022c. It should be understood that, in addition to the cube, the optical combiner 1050 may take the form of various other polyhedra. For example, the optical combiner 1050 may not be a square, but rather a right-angle prism with at least two faces.

[0228] Continuing to refer to Figure 11A, in some embodiments, a monochrome microdisplay 1030b facing directly to the output surface 1051 may, advantageously, output green light. It should be understood that reflective surfaces 1052 and 1054 may have optical losses when reflecting light from the microdisplay. In addition, the human eye is most sensitive to the color green. As a result, a monochrome microdisplay 1030b facing the output surface 1051 preferably outputs green light so that the green light can travel directly through the optical combiner 1050 without needing to be reflected to be output from the optical combiner 1050. However, it will be understood that in some other embodiments, the green monochrome microdisplay may face other surfaces of the optical combiner 1050.

[0229] As discussed herein, the perception of full-color images by a user can be achieved in some embodiments using time-division multiplexing. For example, different light-emitting microdisplays 1030a, 1030b, and 1030c may be activated at different times to produce different primary color images. In such embodiments, different primary color images forming a single full-color image may be displayed sequentially so quickly that the human visual system does not perceive the primary color images as being displayed at different times. That is, all different primary color images forming a single full-color image may be displayed within a duration short enough that the user perceives the primary color images as being presented simultaneously rather than temporally separated. For example, it should be understood that the human visual system may have a flicker fusion threshold. The flicker fusion threshold can be understood as the duration at which the human visual system is unable to distinguish images that are presented at different times. Images presented within that duration may be fused or combined and, as a result, perceived by the user as being presented simultaneously. Flicker images with temporal gaps between images outside that duration are not combined, and the flicker of the images is perceptible. In some embodiments, the duration is 1 / 60th of a second or less, which corresponds to a frame rate of 60 Hz or higher. Preferably, the image frame for any individual eye is provided to the user at a frame rate equal to or higher than the duration of the user's flicker fusion threshold. For example, the frame rate for each left or right eyepiece may be 60 Hz or higher, or 120 Hz or higher, and as a result, the frame rate provided by the light projection system 1010 may be 120 Hz or higher, or 240 Hz or higher, in some embodiments.

[0230] It should be understood that a benefit of time-division multiplexing is that it can reduce the computational load on the processor (e.g., a graphics processor) used to form the displayed image. In some other embodiments, such as when sufficient computational resources are available, all primary color images forming a full-color image may be displayed simultaneously by microdisplays 1030a, 1030b, and 1030c.

[0231] As discussed herein, the microdisplays 1030a, 1030b, and 1030c may each include an array of optical emitters. Figure 11B illustrates an embodiment of an array 1042 of optical emitters 1044. If the associated microdisplay is a monochrome microdisplay, all optical emitters 1044 may be configured to emit light of the same color.

[0232] If the associated microdisplay is a full-color microdisplay, different light emitters 1044 may be configured to emit light of different colors. In such embodiments, the light emitters 1044 may be considered as subpixels and arranged in groups, each group having at least one light emitter configured to emit light of each primary color. For example, if the primary colors are red, green, and blue, each group may have at least one red subpixel, at least one green subpixel, and at least one blue subpixel.

[0233] The optical emitters 1044 are shown arranged in a grid pattern for the sake of illustration, but it will be understood that the optical emitters 1044 may have other regularly repeating spatial arrangements. For example, the number of optical emitters of different primary colors may vary, the size of the optical emitters may vary, and the shape of the optical emitters and / or the shape created by the group of optical emitters may also vary.

[0234] Continuing to refer to Figure 11B, it should be understood that the microemitter 1044 emits light. In addition, manufacturing constraints such as lithography or other patterning and processing limits and / or electrical considerations may limit the proximity to which neighboring optical emitters 1044 are separated. As a result, there may be an area 1045 surrounding the optical emitters 1044 where it is not practical to form other optical emitters 1044. This area 1045 forms an inter-emitter region between the optical emitters 1044. In some embodiments, taking area 1045 into account, the optical emitters have a pitch greater than 1 μm, including 1 to 5 μm, for example, less than 10 μm, less than 8 μm, less than 6 μm, or less than 5 μm, and the emitter size is 2 μm or less, 1.7 μm or less, or 1.3 μm or less. In some embodiments, the emitter size is within a range having the above upper limit and a lower limit of 1 μm. In some embodiments, the emitter size to pitch ratio is 1:1 to 1:5, 1:2 to 1:4, or 1:2 to 1:3.

[0235] Given certain optical emitter device architectures and materials, it should be understood that current congestion can reduce emitter efficiency, and pixel droop can lead to unintentional pixel activation (for example, due to energy directed to one optical emitter leaking to a neighboring optical emitter). As a result, relatively large-area 1045s can be beneficial in reducing current congestion and pixel droop. In some embodiments, the emitter size to pitch ratio is preferably 1:2 to 1:4 or 1:2 to 1:3.

[0236] However, it should also be understood that a large separation between optical emitters (e.g., a small optical emitter to pitch ratio) can undesirably cause visible gaps or dark regions between optical emitters. In some embodiments, lens structures such as optical collimators may be used to effectively fill these dark regions. For example, an optical collimating lens may extend on and around the optical emitter 1044 so that light from the emitter 1044 completely fills the lens. For example, the optical collimating lens may have a width greater than the optical emitter 1044, and in some embodiments, the width of the collimating lens may be approximately equal to the pitch. As a result, the size of the emitter 1044 is effectively increased to extend across the area of ​​the lens, thereby filling part or all of the area 1045. Lens structures such as optical collimators are further discussed herein (e.g., in Figure 30A and related discussions).

[0237] As discussed herein, the photo-emitter 1044 may be an OLED or a micro-LED. It should be understood that an OLED may utilize, for example, a layer of organic material placed between electrodes to emit light. A micro-LED may utilize inorganic materials, such as Group III-V materials like GaAs, GaN, and / or GaIn, for light emission. An example of a GaN material includes InGaN, which in some embodiments may be used to form a blue or green light emitter. An example of a GaIn material includes AlGaInP, which in some embodiments may be used to form a red light emitter. In some embodiments, the photo-emitter 1044 may emit light of an initial color, which may be converted to other desired colors using a phosphor material or quantum dots. For example, the photo-emitter may emit blue light, which excites a phosphor material or quantum dots that convert blue wavelength light to green or red wavelengths.

[0238] Referring here to Figure 12, another embodiment of a wearable display system is illustrated, which includes a light projection system having multiple light-emitting microdisplays 1030a, 1030b, and 1030c. The illustrated display system is similar to the display system in Figure 11A, except that the optical combiner 1050 has a standard X-cube prism configuration and includes light redirection structures 1080a and 1080c to correct the angle of incidence of light onto the reflective surfaces 1052 and 1054 of the X-cube prism. It should be understood that the standard X-cube prism configuration will receive light that is normal to the face of the X-cube and will redirect this light at 45° so that it is output from the lateral face of the X-cube at a normal angle. However, this will cause the image light 1032a, 1032b, and 1032c to be incident on the same internally coupled optical element of the eyepiece 1020. Optical redirection structures 1080a, 1080c may be used to provide different paths for image light 1032a, 1032b, 1032c so that the image light is incident on the associated internal coupling optical elements 1022a, 1022b, 1022c of the waveguide assembly.

[0239] In some embodiments, the optical redirection structures 1080a, 1080c may be lens structures. It should be understood that the lens structures may be configured to receive incident light and redirect the incident light at an angle such that the light is reflected from corresponding reflective surfaces 1052, 1054 and propagates along the optical path toward corresponding internally coupled optical elements 1022a, 1022c. As an example, the optical redirection structures 1080a, 1080c may comprise microlenses, nanolenses, reflective wells, metasurfaces, and liquid crystal gratings. In some embodiments, the microlenses, nanolenses, reflective wells, metasurfaces, and liquid crystal gratings may be organized into arrays. For example, each optical emitter of the microdisplays 1030a, 1030c may be matched with one microlens. In some embodiments, the microlenses or reflective wells may be asymmetrical and / or the optical emitters may be offset from the center of the microlenses in order to redirect the light in a particular direction. In addition, in some embodiments, the optical redirection structures 1080a, 1080c may be collimators, which narrow the angular emission profile of the associated optical emitter and ultimately increase the amount of light internally coupled into the eyepiece 1020. Further details regarding such optical redirection structures 1080a, 1080c are discussed below with respect to Figures 24A-27C.

[0240] Referring here to Figure 13A, in some embodiments, two or more of the internally coupled optical elements 1022a, 1022b, and 1022c may overlap (for example, as seen in the front view in the direction of light propagation into the internally coupled optical elements 1022a, 1022b, and 1022c). Figure 13A illustrates a side view embodiment of a wearable display system with an optical projection system 1010 having a plurality of light-emitting microdisplays 1032a, 1032b, and 1032c, and an eyepiece lens 1020 with overlapping optically coupled optical elements 1022a, 1022c and a non-overlapping optically coupled optical element 1022b. As shown, the internally coupled optical elements 1022a and 1022c overlap, while the internally coupled optical element 1022b is laterally shifted. In other words, the internal coupling optical elements 1022a and 1022c are aligned directly within the paths of the image light 1032a and 1032c, while the image light 1032b follows a different path to the eyepiece 1020 such that it is incident on the area of ​​the eyepiece 1020, which is laterally shifted relative to the area into which the image light 1032a and 1032c are incident.

[0241] As illustrated, the differences between paths for image light 1032b and image light 1032a, 1032c may be established using optical redirection structures 1080a, 1080c. In some embodiments, image light 1032b from the light-emitting microdisplay 1030b travels directly through the optical combiner 1052. Image light 1032a from the light-emitting microdisplay 1032a is redirected by the optical redirection structure 1080a so that it is reflected from the reflective surface 1054 and propagates out of the optical combiner 1050 in the same direction as image light 1032c. It should be understood that image light 1032c from the light-emitting microdisplay 1032c is redirected by the optical redirection structure 1080c so that image light 1032c is reflected from the reflective surface 1052 at an angle such that it propagates out of the optical combiner 1050 in the same direction as image light 1032b. Therefore, the angle of the light redirection by the light redirection structures 1080a, 1080c and the angle of the reflective surfaces 1052, 1054 are configured to provide a common path for the image light 1032a, 1032c out of the optical combiner 1050, which is different from the path of the image light 1032b. In some other embodiments, one or both of the light redirection structures 1080a, 1080c may be omitted, and the reflective surfaces 1052, 1054 within the optical combiner 1050 may be configured to reflect the image light 1032a, 1032c in appropriate separate directions so that it exits the optical combiner 1050 and propagates in the same direction but different from the direction of the image light 1032b. Therefore, after propagation through the projection optical system 1070, the image light 1032a and 1032c are emitted from one exit pupil, while the image light 1032b is emitted from the other exit pupil. In this configuration, the light projection system 1010 can be referred to as a two-pupil projection system.

[0242] In some embodiments, the light projection system 1010 may have a single output pupil and may be referred to as a single pupil projection system. In such embodiments, the light projection system 1010 may be configured to direct image light 1032a, 1032b, 1032c onto a single common area of ​​the eyepiece 1020. Such a configuration is shown in Figure 13B, illustrating a wearable display system with the light projection system 1010 having a plurality of light-emitting microdisplays 1030a, 1030b, 1030c, which are configured to direct light onto a single optical internal coupling area of ​​the eyepiece 1020. In some embodiments, as further discussed herein, the eyepiece 1020 may include a stack of waveguides having overlapping optical internal coupling elements. In some other embodiments, the single optical internal coupling element may be configured to internally couple all primary color light into a single waveguide. The display system in Figure 13B is similar to the display system in Figure 13A, except that the light redirection structures 1080a and 1080c are omitted and an internal coupling optical element 1122a is used in conjunction with the waveguide 1020a. As shown, the internal coupling optical element 1122a internally couples each of the image rays 1032a, 1032b, and 1032c into the waveguide 1020a, which then relays the image rays to the eye 210. In some embodiments, the internal coupling optical element 1122a may include a diffraction grating. In some embodiments, the internal coupling optical element 1122a is a metasurface and / or liquid crystal grating.

[0243] As discussed herein, in some embodiments, the light-emitting microdisplays 1030a, 1030b, and 1030c may be monochrome microdisplays configured to emit light of different colors. In some embodiments, one or more of the light-emitting microdisplays 1030a, 1030b, and 1030c may have groups of light emitters configured to emit light of two or more but not all of the primary colors. For example, a single light-emitting microdisplay may have groups of light emitters with at least one light emitter per group configured to emit blue light and at least one light emitter per group configured to emit green light, and separate light-emitting microdisplays on different faces of the X-cube 1050 may have light emitters configured to emit red light. In some other embodiments, the light-emitting microdisplays 1030a, 1030b, and 1030c may each be full-color displays, each having light emitters of all primary colors. As described herein, utilizing multiple similar microdisplays may provide advantages for dynamic range and increased display brightness.

[0244] In some embodiments, a single full-color light-emitting microdisplay may be used. Figure 14 illustrates an embodiment of a wearable display system with a single light-emitting microdisplay 1030b. The wearable display system of Figure 14 is similar to the wearable display system of Figure 14, but the single light-emitting microdisplay 1030b is a full-color microdisplay configured to emit light of all primary colors. As shown, the microdisplay 1030b emits image light 1032a, 1032b, and 1032c of each primary color. In such embodiments, the optical combiner 1050 (Figure 13B) may be omitted, which is advantageous as it can reduce the weight and size of the wearable display system compared to a system with an optical combiner.

[0245] As discussed above, the internally coupled optical elements of the eyepiece 1020 may take on various configurations. Several embodiments of the configuration of the eyepiece 1020 are discussed below in relation to Figure 15-23C.

[0246] Figure 15 illustrates a side view of an embodiment of the eyepiece 1020 having a stack of waveguides 1020a, 1020b, and 1020c, each with overlapping internal coupling optical elements 1022a, 1022b, and 1022c, respectively. It should be understood that the illustrated waveguide stack may be used instead of the single illustrated waveguide 1020a in Figures 13B and 14. As discussed herein, the internal coupling optical elements 1022a, 1022b, and 1022c are each configured to internally couple light having a specific color (e.g., light of a specific wavelength or range of wavelengths). In the illustrated orientation of the eyepiece 1020, where the image light propagates perpendicularly along the page toward the eyepiece 1020, the internal coupling optical elements 1022a, 1022b, and 1022c are aligned perpendicularly to each other so that they spatially overlap, as seen in the upper and lower figures (a front view in the direction of the image light 1032a, 1032b, and 1032c propagating toward the internal coupling optical elements) (for example, along axes parallel to the propagation direction of the image light 1032a, 1032b, and 1032c).

[0247] Continuing with reference to Figure 15, as discussed herein, the projection system 1010 (Figures 13, 14) is configured to output a first monochrome color image, a second monochrome color image, and a third monochrome color image (e.g., red, green, and blue color images) through a single pupil of the projection system, the monochrome images being formed by image lights 1032a, 1032b, and 1032c, respectively. The internal coupling optical element 1022c is configured to internally couple the image light 1032c into the waveguide 1020c for a first color image so that it propagates through the waveguide 1020c by multiple total internal reflections at the upper and bottom main surfaces of the waveguide 1020c; the internal coupling optical element 1022b is configured to internally couple the image light 1032b into the waveguide 1020b for a second color image so that it propagates through the waveguide 1020b by multiple total internal reflections at the upper and bottom main surfaces of the waveguide 1020b; and the internal coupling optical element 1022a is configured to internally couple the image light 1032a into the waveguide 1020a for a third color image so that it propagates through the waveguide 1020a by multiple total internal reflections at the upper and bottom main surfaces of the waveguide 1020a.

[0248] As discussed herein, the internally coupled optical element 1022c is preferably configured to internally couple substantially all incident light 1032c corresponding to the first color image into the associated waveguide 1020c, while allowing substantially all incident light 1032b, 1032a corresponding to the second and third color images, respectively, to be transmitted without internal coupling. Similarly, the internally coupled optical element 1022b is preferably configured to internally couple substantially all incident image light 1032b corresponding to the second color image into the associated waveguide 1020b, while allowing substantially all incident light corresponding to the third color image to be transmitted without internal coupling.

[0249] In practice, it should be understood that various internal coupling optical elements may not have perfect selectivity. For example, some of the image light 1032b and 1032a may, undesirably, be internally coupled into the waveguide 1020c by the internal coupling optical element 1022c, and some of the incident image light 1032a may, undesirably, be internally coupled into the waveguide 1020b by the internal coupling optical element 1022b. Furthermore, some of the image light 1032c may be transmitted through the internal coupling optical element 1022c and internally coupled into the waveguides 1020b and / or 1020a, respectively, by the internal coupling optical elements 1020b and / or 1020a. Similarly, some of the image light 1032b may be transmitted through the internal coupling optical element 1022b and internally coupled into the waveguide 1020a by the internal coupling optical element 1022a.

[0250] Internal coupling of image light for a color image into an unintended waveguide can result in undesirable optical effects, such as crosstalk and / or afterimages. For example, internal coupling of image light 1032c for a first color image into unintended waveguides 1020b and / or 1020a may result in undesirable crosstalk between the first color image, the second color image, and / or the third color image, and / or undesirable afterimages. In another embodiment, internal coupling of image light 1032b, 1032a for a second or third color image into an unintended waveguide 1020c may result in undesirable crosstalk between the first color image, the second color image, and / or the third color image, and / or undesirable afterimages. In some embodiments, these undesirable optical effects can be mitigated by providing a color filter (e.g., an absorbent color filter) that can reduce the amount of incident light internally coupled into the unintended waveguide.

[0251] Figure 16 illustrates a side view of an embodiment of a waveguide stack with color filters to reduce afterimage or crosstalk between waveguides. The eyepiece 1020 in Figure 16 is similar to that in Figure 15, except for the presence of one or more of the color filters 1024c, 1024b and 1028, 1026. The color filters 1024c and 1024b are configured to reduce the amount of light that is unintentionally internally coupled into waveguides 1020b and 1020a, respectively. The color filters 1028 and 1026 are configured to reduce the amount of image light that propagates through waveguides 1020b and 1020c and is unintentionally internally coupled, respectively.

[0252] Continuing to refer to Figure 16, a pair of color filters 1026, positioned on the upper and lower main surfaces of waveguide 1020c, may be configured to absorb image light 1032a, 1032b, which may be unintentionally internally coupled within waveguide 1020c. In some embodiments, a color filter 1024c, positioned between waveguides 1020c and 1020b, is configured to absorb image light 1032c, which is transmitted through the internally coupled optical element 1022c without being internally coupled. A pair of color filters 1028, positioned on the upper and lower main surfaces of waveguide 1020b, are configured to absorb image light 1032a, which is internally coupled within waveguide 1020b. A color filter 1024b, positioned between waveguides 1020b and 1020a, is configured to absorb image light 1032b, which is transmitted through the internally coupled optical element 710.

[0253] In some embodiments, the color filters 1026 on each major surface of the waveguide 1020c are similarly configured to absorb light of both wavelengths of image light 1032a and 1032b. In some other embodiments, the color filter 1026 on one major surface of the waveguide 1020c may be configured to absorb light of the color of image light 1032a, and the color filters on the other major surface may be configured to absorb light of the color of image light 1032b. In any of the arrays, the color filters 1026 may be configured to selectively absorb image light 1032a and 1032b propagating through the waveguide 1020c by total internal reflection. For example, in the TIR bounce of image light 1032a and 1032b from the major surfaces of the waveguide 1020c, the image light 1032a and 1032b come into contact with the color filters 1026 on their major surfaces, and a portion of that image light is absorbed. Preferably, the propagation of image light 1032c, which is internally coupled via TIR through waveguide 1020c, is not significantly affected by the selective absorption of image light 1032a and 1032b by color filter 1026.

[0254] Similarly, multiple color filters 1028 may be configured as absorbance filters that absorb the internally coupled image light 1032a propagating through the waveguide 1020b by total internal reflection. In the TIR bounce of the image light 1032a from the main surfaces of the waveguide 1020b, the image light 1032a comes into contact with the color filters 1028 on those main surfaces, and a portion of the image light is absorbed. Preferably, the absorption of the image light 1032a is selective and does not affect the propagation of the internally coupled image light 1032b that also propagates through the waveguide 1020b via TIR.

[0255] Continuing with Figure 16, the color filters 1024c and 1024b may also be configured as absorption filters. The color filter 1024c may be substantially transparent to the colored light of image light 1032a and 1032b, such that the image light 1032a and 1032b are transmitted through the color filter 1024c with little or no attenuation, while the colored light of image light 1032c is selectively absorbed. Similarly, the color filter 1024b may be substantially transparent to the colored light of image light 1032a, such that the incident image light 1032a is transmitted through the color filter 1024b with little or no attenuation, while the colored light of image light 1032b is selectively absorbed. The color filter 1024c may be placed on the main surface of the waveguide 1020b (e.g., the upper main surface), as shown in Figure 16. Alternatively, the color filter 1024c may be placed on a separate substrate positioned between waveguides 1020c and 1020b. Similarly, the color filter 1024b may be placed on the main surface of waveguide 1020a (e.g., the upper main surface). Alternatively, the color filter 1024b may be placed on a separate substrate positioned between waveguides 1020b and 1020a. It should be understood that the color filters 1024c and 1024b may be perpendicularly aligned with a single pupil of the projector that outputs image light 1032a, 1032b, 1032c (in an orientation such that the image light 1032a, 1032b, 1032c propagates perpendicularly to the waveguide stack 1020, as shown in the figure).

[0256] In some embodiments, the color filters 1026 and 1028 may have a single-pass attenuation coefficient of less than about 10% (e.g., less than or equal to about 5%, less than or equal to about 2%, and greater than about 1%) to avoid significant undesirable absorption of light (e.g., light of the colors of image light 1032a, 1032b propagating through the thickness of waveguides 1020c, 1020b from the ambient environment and / or other waveguides). Various embodiments of the color filters 1024c and 1024b may be configured to have a low attenuation coefficient for wavelengths to be transmitted and a high attenuation coefficient for wavelengths to be absorbed. For example, in some embodiments, the color filter 1024c may be configured to transmit more than 80%, more than 90%, or more than 95% of the incident light having the colors of the image light 1032a and 1032b, and to absorb more than 80%, more than 90%, or more than 95% of the incident light having the color of the image light 1032a. Similarly, the color filter 1024b may be configured to transmit more than 80%, more than 90%, or more than 95% of the incident light having the color of the image light 1032a, and to absorb more than 80%, more than 90%, or more than 95% of the incident light having the color of the image light 1032b.

[0257] In some embodiments, the color filters 1026, 1028, 1024c, and 1024b may comprise a layer of color-selective light-absorbing material deposited on one or both surfaces of the waveguides 1020c, 1020b, and / or 1020a. The color-selective light-absorbing material may comprise dyes, inks, or other light-absorbing materials such as metals, semiconductors, and dielectrics. In some embodiments, the absorption of materials such as metals, semiconductors, and dielectrics may be color-selective by utilizing these materials to form a subwavelength grating (e.g., a grating that does not diffract light). The grating may be made from plasmonics (e.g., gold, silver, and aluminum) or semiconductors (e.g., silicon, amorphous silicon, and germanium).

[0258] Color-selective materials may be deposited on a substrate using various deposition methods. For example, color-selective light-absorbing materials may be deposited on a substrate using jet deposition techniques (e.g., inkjet deposition). Inkjet deposition can facilitate the deposition of thin layers of color-selective light-absorbing materials. Because inkjet deposition allows deposition to be localized on a selected area of ​​the substrate, inkjet deposition provides a degree of control over the thickness and composition of the layer of color-selective light-absorbing material, including providing non-uniform thickness and / or composition across the substrate. In some embodiments, the color-selective light-absorbing material deposited using inkjet deposition may have a thickness of about 10 nm to about 1 micron (e.g., about 10 nm to about 50 nm, about 25 nm to about 75 nm, about 40 nm to about 100 nm, about 80 nm to about 300 nm, about 200 nm to about 500 nm, about 400 nm to about 800 nm, about 500 nm to about 1 micron, or any value within the range / sub-range defined by any of these values). Controlling the thickness of the deposited layer of color-selective light-absorbing material can be advantageous in achieving a color filter with a desired attenuation coefficient. Furthermore, layers of different thicknesses may be deposited on different parts of the substrate. In addition, different compositions of color-selective light-absorbing material may be deposited on different parts of the substrate using inkjet deposition. Such variations in composition and / or thickness can, advantageously, allow for location-specific variations in absorbance. For example, in the area of ​​a waveguide where transmission of ambient light (to allow the viewer to see the surrounding environment) is not required, the composition and / or thickness may be selected to provide high absorbance or attenuation of selected wavelengths of light. Other deposition methods such as coating, spin coating, and spraying may also be employed to deposit color-selective light-absorbing material onto the substrate.

[0259] Figure 17 illustrates upper and lower embodiments of the waveguide assembly shown in Figures 15 and 16. As shown, the internally coupled optical elements 1022a, 1022b, and 1022c overlap spatially. In addition, the waveguides 1020a, 1020b, and 1020c may be vertically aligned with the associated optical dispersion elements 730, 740, and 750 and associated externally coupled optical elements 800, 810, and 820 of each waveguide. The internally coupled optical elements 1022a, 1022b, and 1022c are configured such that the incident image light 1032a, 1032b, and 1032c (Figures 15 and 16) are internally coupled within the waveguides 1020a, 1020b, and 1020c, respectively, so that the image light propagates toward the associated optical dispersion elements 730, 740, and 750 by TIR.

[0260] Figure 18 illustrates another embodiment of the waveguide assembly shown in the upper and lower views of Figures 15 and 16. As in Figure 17, the internally coupled optical elements 1022a, 1022b, and 1022c overlap spatially, and the waveguides 1020a, 1020b, and 1020c are vertically aligned. However, instead of the associated optical dispersion elements 730, 740, and 750 and associated externally coupled optical elements 800, 810, and 820 for each waveguide, there are combined OPE / EPE 1281, 1282, and 1283, respectively. The internally coupled optical elements 1022a, 1022b, and 1022c are configured such that the incident image light 1032a, 1032b, and 1032c (Figures 15 and 16) are internally coupled within waveguides 1020a, 1020b, and 1020c, respectively, so that the image light propagates toward the associated combined OPE / EPE 1281, 1282, and 1283 by TIR.

[0261] Figures 15-18 show overlapping internally coupled optical elements for a single pupil configuration of the display system, but it should be understood that the display system may have a two-pupil configuration in some embodiments. In such a configuration, where three primary colors are utilized, the image light for two colors may have overlapping internally coupled optical elements, while the image light for a third color may have laterally shifted internally coupled optical elements. For example, the optical combiner 1050 (Figures 11A, 12, 13A-13B) and / or the optical redirection structures 1080a, 1080c may be configured to direct the image light through the projection optical system 1070 such that the image light for two colors is incident directly on the overlapping area of ​​the eyepiece 1020, while the image light for the other color is incident on an area that is laterally shifted. For example, the reflective surfaces 1052 and 1054 (Figure 11A) may be angled such that image light of one color follows a common optical path with image light from the light-emitting microdisplay 1030b, while image light of another color follows a different optical path. In some embodiments, instead of having both the light redirection structures 1080a and 1080c (Figure 12), one of these light redirection structures may be omitted so that only the light from one of the microdisplays 1030a and 1030c is angled and provides a different optical path from the light emitted by the other two microdisplays.

[0262] Figure 19A illustrates a side view of an embodiment of an eyepiece having a waveguide stack with several overlapping internally coupled optical elements and several laterally shifted internally coupled optical elements. The eyepiece in Figure 19A is similar to the eyepiece in Figure 15, except that one of the internally coupled optical elements is laterally shifted relative to the other. In the illustrated orientation of the eyepiece 1020, where the image light propagates perpendicularly along the page toward the eyepiece 1020, the internally coupled optical elements 1022a, 1022c are aligned perpendicularly to each other so that they spatially overlap each other, as seen in the front view, in the direction of the image light 1032a, 1032c propagating to the internally coupled optical elements 1022a, 1022b, 1022c (for example, along an axis parallel to the propagation direction of the image light 1032a, 1032c). As seen in the same front view (for example, as seen in the upper and lower views in the illustrated orientation), the internally coupled optical element 1022b is laterally offset relative to the other internally coupled optical elements 1022a and 1022c. The light for internally coupled optical element 1022b is output to the eyepiece 1020 through a different exit pupil than the light for internally coupled optical elements 1022a and 1022c. It should be understood that the illustrated waveguide stack, comprising waveguides 1020a, 1020b, and 1020c, may be used instead of the single illustrated waveguide 1020a in Figures 13 and 14.

[0263] Continuing to refer to Figure 19, the internal coupling optical element 1022c is configured to internally couple the image light 1032c into the waveguide 1020c so that it propagates through the waveguide 1020c by multiple total internal reflections between the upper and lower main surfaces of the waveguide 1020c; the internal coupling optical element 1022b is configured to internally couple the image light 1032b into the waveguide 1020b so that it propagates through the waveguide 1020b by multiple total internal reflections between the upper and lower main surfaces of the waveguide 1020b; and the internal coupling optical element 1022a is configured to internally couple the image light 1032a into the waveguide 1020a so that it propagates through the waveguide 1020a by multiple total internal reflections between the upper and lower main surfaces of the waveguide 1020a.

[0264] The internal coupling optical element 1022c is preferably configured to internally couple all incident light 1032c into the associated waveguide 1020c while transmitting all incident light 1032a. On the other hand, image light 1032b can propagate to the internal coupling optical element 1022b without needing to propagate through any other internal coupling optical element. This may be advantageous in some embodiments by allowing light to which the eye is more sensitive to to be incident on the desired internal coupling optical element without any loss or distortion associated with propagation through other internal coupling optical elements. Although not limited by theory, in some embodiments, image light 1032b is green light to which the human eye is more sensitive. While waveguides 1020a, 1020b, and 1020c are illustrated as being arranged in a specific order, it should be understood that in some embodiments, the order of waveguides 1020a, 1020b, and 1020c may differ.

[0265] As discussed herein, it should be understood that the internal coupling optical element 1022c above the internal coupling optical element 1022a may not have perfect selectivity. Some of the image light 1032a may, undesirably, be internally coupled into the waveguide 1020c by the internal coupling optical element 1022c, and some of the image light 1032c may be transmitted through the internal coupling optical element 1022c, and subsequently, the image light 1032c may strike the internal coupling optical element 1020a and be internally coupled into the waveguide 1020a. As discussed herein, such undesirable internal coupling may be visible as afterimage or crosstalk.

[0266] Figure 19B illustrates a side view of an embodiment of the eyepiece of Figure 19A, with a color filter to reduce afterimage or crosstalk between waveguides. In particular, color filters 1024c and / or 1026 are added to the structure shown in Figure 19A. As illustrated, the internal coupling optical element 1022c may unintentionally internally couple a portion of the image light 1032a into the waveguide 1020c. In addition, or alternatively, a portion of the image light 1032c may undesirably be transmitted through the internal coupling optical element 1022c and then unintentionally internally coupled by the internal coupling optical element 1022a.

[0267] To mitigate unintentional internal coupling of image light 1032a propagating through waveguide 1022c, an absorbent color filter 1026 may be provided on one or both primary surfaces of waveguide 1022c. The absorbent color filter 1026 may be configured to absorb light of the color of image light 1032a that would otherwise be unintentionally internally coupled. As shown in the figure, the absorbent color filter 1026 is positioned in the general propagation direction of image light through waveguide 1020c. Thus, the absorbent color filter 1026 is configured to absorb image light 1032a as it propagates through waveguide 1020c by TIR and comes into contact with the absorbent color filter 1026 as it is reflected from one or both primary surfaces of waveguide 1020c.

[0268] Continuing with Figure 19B, an absorbent color filter 1024c may be provided in front of the internally coupled optical element 1022a to reduce the image light 1032c that propagates through the internally coupled optical element 1022c without being internally coupled. The absorbent color filter 1024c is configured to absorb the color of the image light 1032c and prevent that light from propagating to the internally coupled optical element 1022a. It is illustrated between waveguides 1020c and 1020b, but in some other embodiments, the absorbent color filter 1024c may be placed between waveguides 1020b and 1020a. Further details regarding the composition, formation, and properties of the absorbent color filters 1024c and 1026 should be understood to be provided in the discussion of Figure 16.

[0269] Furthermore, in the embodiments illustrated in Figures 16 and 19B, one or more of the color filters 1026, 1028, 1024c, and 1024b may be omitted if one or more internally coupled optical elements 1022a, 1022b, and 1022c are intended to be internally coupled into the associated waveguides 1020a, 1020b, and 1022c, respectively, and have sufficiently high selectivity with respect to the color of light.

[0270] Figure 20A illustrates an embodiment of the upper and lower view of the eyepiece in Figures 19A and 19B. As shown, the internally coupled optical elements 1022a and 1022c overlap spatially, while the internally coupled optical element 1022b is laterally shifted. In addition, the waveguides 1020a, 1020b and 1020c may be vertically aligned with the associated optical dispersion elements 730, 740, and 750 and associated externally coupled optical elements 800, 810, and 820 of each waveguide. The internally coupled optical elements 1022a, 1022b, and 1022c are configured to internally couple the incident image light 1032a, 1032b, and 1032c (Figures 15 and 16) into waveguides 1020a, 1020b, and 1020c, respectively, so that the image light propagates toward the associated optical dispersion elements 730, 740, and 750 by TIR.

[0271] Figure 20B illustrates another embodiment of the waveguide assembly shown in the upper and lower views of Figures 19A and 19B. As in Figure 20A, the internally coupled optical elements 1022a and 1022c overlap spatially, the internally coupled optical elements are laterally shifted, and the waveguides 1020a, 1020b, and 1020c are vertically aligned. However, instead of the associated optical dispersion elements 730, 740, and 750 and associated externally coupled optical elements 800, 810, and 820 for each waveguide, there are combined OPE / EPE 1281, 1282, and 1283, respectively. The internally coupled optical elements 1022a, 1022b, and 1022c are configured to internally couple the incident image light 1032a, 1032b, and 1032c (Figures 15 and 16) into waveguides 1020a, 1020b, and 1020c, respectively, so that the image light propagates toward the associated combined OPE / EPE 1281, 1282, and 1283 by TIR.

[0272] Referring to Figure 21, it should be understood that re-bouncement of internally coupled light can, undesirably, occur within the waveguide. Re-bouncement occurs when internally coupled light propagating along the waveguide strikes the internal coupling optical element a second time, or at a subsequent time, after the initial internal coupling incidence. Re-bouncement can result in some of the internally coupled light being undesirably externally coupled and / or absorbed by the material of the internal coupling optical element. External coupling and / or absorption can, undesirably, lead to a reduction in the overall internal coupling efficiency and / or the uniformity of the internally coupled light.

[0273] Figure 21 illustrates a side view of an embodiment of re-bounce within waveguide 1030a. As shown, image light 1032a is internally coupled into waveguide 1030a by internal coupling optical element 1022a. The internal coupling optical element 1022a generally redirects the image light 1032a to propagate through the waveguide in direction 1033. Re-bounce can occur when the internally coupled image light is internally reflected or bounced from the main surface of waveguide 1030a opposite the internal coupling optical element 1022a, incident on the internal coupling optical element 1022a, or undergoes a second bounce (re-bounce). The distance between two neighboring bounces on the same surface of waveguide 1030a is indicated by a spacing 1034.

[0274] While not limited by theory, it should be understood that the internally coupled optical element 1022a can behave symmetrically. That is, the incident light can be redirected so that it propagates through the waveguide at a TIR angle. However, light incident on the diffractive optical element at a TIR angle (depending on re-bounce, etc.) can also be externally coupled. In addition, or alternatively, in embodiments where the internally coupled optical element 1022a is coated with a reflective material, it should be understood that reflection of light from a layer of material such as a metal can also involve partial absorption of the incident light, since the reflection may involve absorption and emission of light from the material. As a result, external coupling and / or absorption of light can undesirably cause loss of internally coupled light. Therefore, re-bounced light can suffer significant loss compared to light that interacts with the internally coupled optical element 1022a only once.

[0275] In some embodiments, the internal coupling element is configured to mitigate the loss of internally coupled image light due to re-bounce. Generally, re-bounce of internally coupled light occurs in the propagation direction 1033 of the internally coupled optical element 1022a toward the end 1023. For example, light internally coupled at the end of the internally coupled optical element 1022a facing the end 1023 may re-bounce if the spacing 1034 for that light is sufficiently short. To avoid such re-bounce, in some embodiments, the internally coupled optical element 1022a is truncated at the propagation direction end 1023 to reduce the width 1022w of the internally coupled optical element 1022a, along which re-bounce is likely to occur. In some embodiments, the truncation may be a complete truncation of all structures of the internally coupled optical element 1022a (e.g., metallization and diffraction grating). In some other embodiments, for example, if the internal coupling optical element 1022a includes a metallized diffraction grating, a portion of the internal coupling optical element 1022a at the propagation direction end 1023 may not be metallized such that the propagation direction end 1023 of the internal coupling optical element 1022a absorbs little of the re-bounced light and / or externally couples the re-bounced light with lower efficiency. In some embodiments, the diffraction region of the internal coupling optical element 1022a may have a width along the propagation direction 1033 that is shorter than its length perpendicular to the propagation direction 1033, and / or may be sized and shaped so that a first portion of the image light 1032a is incident on the internal coupling optical element 1022a and a second portion of the light beam does not occur on the internal coupling optical element 1022a but collides on the waveguide 1030a. Waveguide 1032a and optical internal coupling element 1022a are illustrated separately for clarity, but it should be understood that re-bounce and strategies for reducing re-bounce discussed may be applied to any of the internal coupling elements disclosed herein. Also, it should be understood that the spacing 1034 is related to the thickness of waveguide 1030a (larger thickness results in a larger spacing 1034). In some embodiments, the thickness of individual waveguides may be selected to set the spacing 1034 so that re-bounce does not occur.Further details regarding re-bounce mitigation can be found in U.S. Provisional Application No. 62 / 702,707, filed on 24 July 2018 (the entire disclosure of which is incorporated herein by reference).

[0276] Figures 22A-23C illustrate upper and lower view embodiments of an eyepiece having internally coupled optical elements configured to reduce re-bounce. The internally coupled optical elements 1022a, 1022b, and 1022c are configured to internally couple light so that it propagates in the propagation direction toward the associated light dispersion elements 730, 740, and 750 (Figures 22A-22C) or the combined OPE / EPE 1281, 1282, and 1283 (Figures 23A-23C). As shown, the internally coupled optical elements 1022a, 1022b, and 1022c may have shorter dimensions along the propagation direction and longer dimensions along the transverse axis. For example, each of the internally coupled optical elements 1022a, 1022b, and 1022c may have a rectangular shape with shorter sides along the propagation direction axis and longer sides along the orthogonal axis. It should be understood that the internal coupling optical elements 1022a, 1022b, and 1022c may have other shapes (e.g., orthogonal, hexagonal, etc.). In addition, different internal coupling optical elements 1022a, 1022b, and 1022c may have different shapes in some embodiments. Preferably, as shown in the figures, non-overlapping internal coupling optical elements may be positioned so that they are not in the propagation direction of the other internal coupling optical elements. For example, as shown in Figures 22A, 22B, 23A, and 23B, non-overlapping internal coupling optical elements may be arranged along lines that intersect (e.g., orthogonal) the axes of propagation.

[0277] It should be understood that the waveguide assemblies in Figures 22A-22C are similar, except for the overlap of internally coupled optical elements 1022a, 1022b, and 1022c. For example, Figure 22A shows internally coupled optical elements 1022a, 1022b, and 1022c without overlap. Figure 22B shows overlapping internally coupled optical elements 1022a and 1022c, and non-overlapping internally coupled optical element 1022b. Figure 22C shows the overlap among all internally coupled optical elements 1022a, 1022b, and 1022c.

[0278] The waveguide assemblies in Figures 23A-23C are also similar, except for the overlap of internally coupled optical elements 1022a, 1022b, and 1022c. Figure 23A illustrates the internally coupled optical elements 1022a, 1022b, and 1022c without overlap. Figure 23B illustrates the overlapping internally coupled optical elements 1022a and 1022c, and the non-overlapping internally coupled optical element 1022b. Figure 22C illustrates the overlap among all internally coupled optical elements 1022a, 1022b, and 1022c.

[0279] Referring here to Figure 24A, it should be understood that light-emitting microdisplays have high etendue, which presents challenges regarding efficient light utilization. As discussed herein, light-emitting microdisplays may include multiple individual light emitters. Each of these light emitters may have a large-angle emission profile, e.g., a Lambertian or near-Lambertian emission profile. Undesirably, all of this light may be captured and not directed towards the eyepiece of the display system.

[0280] Figure 24A illustrates an embodiment of the angular emission profiles of light emitted by individual light emitters 1044 of a light-emitting microdisplay 1032 and light captured by a projection optical system 1070. The illustrated light-emitting microdisplay 1032 may correspond to any of the light-emitting microdisplays disclosed herein, including light-emitting microdisplays 1032a, 1032b, and 1032c. As illustrated, the projection optical system 1070 may be sized to capture light having an angular emission profile 1046. However, the angular emission profile 1046 in the light emitter 1044 is significantly larger, and not all of the light emitted by the light emitter 1044 is incident on the projection optical system 1070, nor is it necessarily incident at an angle through which the light will propagate in and through the projection optical system 1070. As a result, some of the light emitted by the light emitter 1044 may be undesirably captured and ultimately relayed to the user's eye, becoming "wasted" as it does not form an image. This can result in an image where more of the light emitted by the light emitter 1040 appears dimmer than what would be expected if it ultimately reached the user's eye.

[0281] In some embodiments, one strategy for capturing more of the light emitted by the light emitter 1040 is to increase the size of the projection optics 1070 and increase the numerical aperture size of the projection optics 1070 that captures the light. In addition, or alternatively, the projection optics 1070 may also be formed of a high refractive index material (e.g., having a refractive index greater than 1.5), which may also facilitate focusing. In some embodiments, the projection optics 1070 may utilize lenses that are sized to capture a desired high percentage of the light emitted by the light emitter 1044. In some embodiments, the projection optics 1070 may have an elongated exit pupil and be configured to emit a light beam having a cross-sectional profile similar to the shape of the internally coupled optical elements 1022a, 1022b, and 1022c in Figures 22A-23C. For example, the projection optics 1070 may be elongated to dimensions corresponding to the elongated dimensions of the internally coupled optical elements 1022a, 1022b, and 1022c in Figures 22A-23C. While not limited by theory, such extended internal coupling optical elements 1022a, 1022b, and 1022c may improve etendue mismatch between the light-emitting microdisplay and the eyepiece 1020 (Figures 22A–23C). In some embodiments, the waveguide thickness of the eyepiece 1020 (e.g., Figures 11A and 12–23C) may be selected to increase the percentage of light effectively captured by reducing rebounces, for example, by increasing the rebounce interval, as discussed herein.

[0282] In some embodiments, one or more optical collimators may be used to reduce or narrow the angular emission profile of light from the optical emitter 1044. As a result, more of the light emitted by the optical emitter 1044 is captured by the projection optics 1070 and relayed to the user's eye, which can, advantageously, increase the brightness of the image and the efficiency of the display system. In some embodiments, the optical collimators may enable the focusing efficiency of the projection optics (the percentage of light emitted by the optical emitter 1044 that is captured by the projection optics) to reach values ​​of 80% or more, 85% or more, or 90% or more, including about 85–95% or 85–90%. In addition, the angular emission profile of light from the optical emitter 1044 can be reduced to 60° or less, 50° or less, or 40° or less (e.g., from 180°). In some embodiments, the reduced angular emission profile may be in the range of about 30–60°, 30–50°, or 30–40°. It should be understood that the light from the optical emitter 1044 can create a cone shape, and the optical emitter 1044 is located at the apex of the cone. The angular emission profile refers to the angle created by the sides of the cone, and the associated optical emitter 1044 is at the apex of that angle (as seen in the cross-section obtained along a plane extending through the center of the cone and including the apex of the cone).

[0283] Figure 24B illustrates an embodiment of angle emission profile narrowing using an array of optical collimators. As shown, the light-emitting microdisplay 1032 includes an array of optical emitters 1044, which emit light with an angle emission profile 1046. An array of optical collimators 1300 is positioned in front of the optical emitters 1044. In some embodiments, each optical emitter 1044 is matched one-to-one with an associated optical collimator 1302 (one optical collimator 1302 per optical emitter 1044). Each optical collimator 1302 redirects the incident light from the associated optical emitter 1044, providing a narrowed angle emission profile 1047. Thus, a relatively large angle emission profile 1046 is narrowed to a smaller angle emission profile 1047.

[0284] In some embodiments, the optical collimator 1302 and array 1300 may be part of the optical redirection structures 1080a, 180c in Figures 12 and 13A. Thus, the optical collimator 1302 may narrow the angular emission profile of the optical emitter 1044 and redirect the light so that it propagates into the optical combiner 1050 at an appropriate angle, defining multiple optical paths and associated multiple exit pupils. It should be understood that the light may be redirected in a specific direction by appropriately shaping the optical collimator 1302.

[0285] Preferably, the optical collimator 1302 is positioned in close proximity to the optical emitter 1044 and captures a large proportion of the light emitted by the optical emitter 1044. In some embodiments, a gap may exist between the optical collimator 1302 and the optical emitter 1044. In some other embodiments, the optical collimator 1302 may be in contact with the optical emitter 1044. It should be understood that the angular emission profile 1046 may produce a broad cone of light. Preferably, all or most of the cone of light from the optical emitter 1044 is incident on a single associated optical collimator 1302. Thus, in some embodiments, each optical emitter 1044 is smaller than the light-receiving surface of the associated optical collimator 1302 (occupies a smaller area). In some embodiments, each optical emitter 1044 has a width smaller than the distance between neighboring, distant optical emitters 1044.

[0286] Advantages of the optical collimator 1302 include increased efficiency in light utilization and reduced crosstalk between neighboring optical emitters 1044. It should be understood that crosstalk between optical emitters 1044 can occur when light from a neighboring optical emitter is captured by an optical collimator 1302 that is not associated with that neighboring optical emitter. This captured light propagates to the user's eye, thereby providing false image information about a given pixel.

[0287] Referring to Figures 24A and 24B, the size of the beam of light captured by the projection optical system 1070 can affect the size of the beam of light emitting from the projection optical system 1070. As shown in Figure 24A, without an optical collimator, the emitted beam may have a relatively large width 1050. As shown in Figure 24B, with the optical collimator 1302, the emitted beam may have a smaller width 1052. Therefore, in some embodiments, the optical collimator 1302 may be used to provide a desired beam size for internal coupling into the eyepiece. For example, the amount by which the optical collimator 1302 narrows the angular emission profile 1046 may be selected based at least partially on the size of the internal coupling optical element in the eyepiece to which the light output by the projection optical system 1070 is directed.

[0288] It should be understood that the optical collimator 1302 may take various forms. For example, in some embodiments, the optical collimator 1302 may be a microlens or lenslet. As discussed herein, each microlens preferably has a width exceeding the width of the associated optical emitter 1044. The microlenses may be formed from a curved transparent material such as glass or polymer, containing a resin such as photoresist and epoxy. In some embodiments, the optical collimator 1302 may be a nanolens, for example, a diffractive optical grating. In some embodiments, the optical collimator 1302 may be a metasurface and / or liquid crystal grating. In some embodiments, the optical collimator 1302 may take the form of a reflective well.

[0289] It should be understood that different optical collimators 1302 may have different dimensions and / or shapes depending on the wavelength or color of the light emitted by the associated optical emitter 1044. Therefore, with respect to a full-color light-emitting microdisplay, the array 1300 may include multiple optical collimators 1302, each having different dimensions and / or shapes depending on the color of the light emitted by the associated optical emitter 1044. In embodiments where the light-emitting microdisplay is a monochrome microdisplay, the array 1300 may be simplified, with each optical collimator 1302 in the array configured to redirect light of the same color. By using such a monochrome microdisplay, the optical collimators 1302 may, in some embodiments, be similar across the array 1300.

[0290] Continuing with reference to Figure 24B, as discussed herein, the optical collimators 1302 may have a one-to-one association with the optical emitters 1044. For example, each optical emitter 1044 may have discrete associated optical collimators 1302. In some other embodiments, the optical collimators 1302 may be extended so that they extend across a plurality of optical emitters 1044. For example, in some embodiments, the optical collimators 1302 may be extended toward the other side of the page and extend in front of a row of multiple optical emitters 1044. In some other embodiments, a single optical collimator 1302 may extend across a column of optical emitters 1044. In yet another embodiment, the optical collimators 1302 may comprise stacked columns and / or rows of lens structures (e.g., nanolens structures, microlens structures, etc.).

[0291] As described above, the optical collimator 1302 may take the form of a reflective well. Figure 25A illustrates an embodiment of a side view of an array of tapered reflective wells for directing light to a projection optical system. As shown, the optical collimator array 1300 may include a substrate 1301 on which a plurality of optical collimators 1302 in the form of reflective wells may be formed. Each well may include at least one optical emitter 1044, which may emit light with a Lambertian angle emission profile 1046. The reflective walls 1303 of the wells of the optical collimator 1302 are tapered and reflect the emitted light so that it is output from the well with a narrower angle emission profile 1047. As shown, the reflective walls 1303 may be tapered such that their cross-sectional size increases with distance from the optical emitter 1044. In some embodiments, the reflective walls 1303 may be curved. For example, side 1303 may have the shape of a composite parabolic concentrator (CPC).

[0292] Referring here to Figure 25B, an embodiment of a side view of an asymmetric tapered reflective well is illustrated. As discussed herein, it may be desirable to use the optical collimator 1302 to direct light in a specific direction that is not normal to the surface of the optical emitter 1044, for example, as illustrated in Figures 12A-13A. In some embodiments, the optical collimator 1302 may be asymmetric, as can be seen in the side view illustrated in Figure 25B, with the upper edge 1303a forming a different angle (e.g., a larger angle) with respect to the surface of the optical emitter 1044 than the lower edge 1303b. For example, the angles of the reflective walls 1303a, 1303b with respect to the optical emitter 1044 may differ on different edges of the optical collimator 1302 in order to direct light in a specific non-normal direction. Therefore, as illustrated, the light emitted from the optical collimator 1302 may generally propagate in a direction 1048 that is not normal to the surface of the optical emitter 1044. In some other embodiments, the taper of the upper edge 1303a may differ from the taper of the lower edge in order to direct the light in direction 1048. For example, the upper edge 1303a may widen over a wider area than the lower edge 1303b.

[0293] Continuing with reference to Figure 25, the substrate 1301 may be formed from a variety of materials having sufficient mechanical integrity to maintain the desired shape of the reflective wall 1303. Examples of preferred materials include metal, plastic, and glass. In some embodiments, the substrate 1301 may be a plate of material. In some embodiments, the substrate 1301 is a continuous, one-piece material. In some other embodiments, the substrate 1301 may be formed by joining two or more material pieces together.

[0294] The reflective wall 1303 may be formed within the substrate 1301 by various methods. For example, the wall 1303 may be formed into a desired shape by machining the substrate 1301 or otherwise removing material and defining the wall 1303. In some other embodiments, the wall 1303 may be formed as the substrate 1301 is formed. For example, the wall 1303 may be molded into the substrate 1301 as the substrate 1301 is molded into its desired shape. In some other embodiments, the wall 1303 may be defined by rearranging the material after the formation of the body 2200. For example, the wall 1303 may be defined by imprinting.

[0295] Once the contours of the walls 1303 are formed, they may undergo further processing to form surfaces having a desired reflectivity. In some embodiments, the surface of the substrate 1301 itself may be reflective; for example, the body may be formed from a reflective metal. In such cases, further processing may include smoothing or polishing the inner surface of the walls 1303 to increase their reflectivity. In some other embodiments, the inner surface of the reflector 2110 may be backed with a reflective coating, for example, by a vapor deposition process. For example, the reflective layer may be formed by physical vapor deposition (PVD) or chemical vapor deposition (CVD).

[0296] It should be understood that the location of the optical emitter relative to the associated optical collimator can affect the direction of light emitted outward from the optical collimator. This is illustrated, for example, in Figures 26A–26C, which illustrate an example of the difference in optical paths for optical emitters at different positions relative to the centerline of the associated optical collimator in the upper layer. As shown in Figure 26A, the light-emitting microdisplay 1030 has a plurality of optical emitters 1044a, each having an associated optical collimator 1302, which facilitates the output of light having a narrowed angular emission profile 1047. The light passes through a projection optical system 1070 (represented as a simple lens for ease of illustration), which focuses the light from the various optical emitters 1044a onto an area 1402a.

[0297] Continuing with Figure 26A, in some embodiments, each optical collimator 1302 may be symmetrical and have a centerline extending along the axis of symmetry of the optical collimator. In the illustrated configuration, the optical emitter 1044a is positioned on each of the centerlines of the optical collimators 1302.

[0298] Referring here to Figure 26B, the optical emitter 1044b is offset by a distance of 1400 from the center line of its individual optical collimator 1302. This offset causes the light from the optical emitter 1044b to follow a different path through the optical collimator 1302, which outputs light from the optical emitter 1044b with a narrowed angular emission profile 1047b. The projection optical system 1070 then focuses the light from the optical emitter 1044b onto area 1402b, which is offset relative to area 1402a onto which light from the optical emitter 1044a is focused.

[0299] Referring to Figure 26C, an optical emitter 1044c is shown that is offset from both optical emitters 1044a and 1044b. This offset causes the light from optical emitter 1044c to follow a different path than the light from optical emitters 1044a and 1044b, passing through the optical collimator 1302. This causes the optical collimator 1302 to output the light from optical emitter 1044c to the projection optics 1070, with a narrowed angular emission profile that follows a different path than the light from optical emitters 1044a and 1044b. Finally, the projection optics 1070 focuses the light from optical emitter 1044c onto area 1402c, which is offset relative to areas 1402a and 1402b.

[0300] Referring to Figures 26A-26C, the threefold symmetry axes of the optical emitters 1044a, 1044b, and 1044c may share a common optical collimator 1302. In some embodiments, the microdisplay 1030 may be a full-color microdisplay, and each optical emitter 1044a, 1044b, and 1044c may be configured to emit light of different primary colors. Advantageously, the offset areas 1402a, 1402b, and 1402c may, in some embodiments, correspond to internally coupled optical elements of a waveguide. For example, areas 1402a, 1402b, and 1402c may correspond to the internally coupled optical elements 1022a, 1022b, and 1022c in Figures 11A and 12, respectively. Therefore, the offset orientation of the optical collimator 1302 and the optical emitters 1044a, 1044b, and 1044c is advantageous in that it can provide a simple three-pupil projection system 1010 using a full-color light-emitting microdisplay.

[0301] As described herein, the optical collimator 1302 may also take the form of a nanolens. Figure 27 illustrates an embodiment of a side view of individual optical emitters 1044 of an optical-emitting microdisplay 1030 with an upper array 1300 of optical collimators 1302, which are nanolenses. As discussed herein, each individual optical emitter 1044 may have an associated optical collimator 1302. The optical collimator 1302 redirects the light from the optical emitter 1044, narrowing the large-angle emission profile 1046 of the optical emitter 1044 and outputting light with a narrowed-angle emission profile 1047.

[0302] Continuing with reference to Figure 27, in some embodiments, the optical collimator 1302 may be a lattice structure. In some embodiments, the optical collimator 1302 may be a lattice formed by alternatingly elongated discrete extensions (e.g., lines) of materials having different refractive indices. For example, the extensions of material 1306 may be elongated in and out of the page and may be formed within the material of the substrate 1308 and thereby separated. In some embodiments, the elongated extensions of material 1306 may have subwavelength widths and pitches (e.g., widths and pitches smaller than the wavelength of light that the optical collimator 1302 is configured to receive from the optical emitter 1044 to which it is associated). In some embodiments, the pitch 1304 may be 30 to 300 nm, the lattice depth may be 10 to 1,000 nm, the refractive index of the material forming the substrate 1308 may be 1.5 to 3.5, and the refractive index of the material forming the lattice features 1306 may be 1.5 to 2.5 (and different from the refractive index of the material forming the substrate 1308).

[0303] The illustrated lattice structure may be formed by various methods. For example, the substrate 1308 may be etched or nanoimprinted to define grooves, which may be filled with a material having a different refractive index than the substrate 1308 to form the lattice features 1306.

[0304] As an advantage, nanolens arrays can offer various benefits. For example, the focusing efficiency of nanolenslets can be high, for example, 80-95%, including 85-90%, accompanied by excellent reduction of the angular emission profile, for example, a reduction of 30-40° (from 180°). In addition, low levels of crosstalk can be achieved because each nanolens optical collimator 1302 can have physical dimensions and properties (e.g., pitch, depth, refractive index of the material forming the features 1306 and substrate 1308) that are selected to preferably provide high extinction (with respect to wavelengths of light of other colors), while acting on light at a specific incident angle as a specific color and possibility. Furthermore, nanolens arrays can have a flat profile (e.g., formed on a flat substrate), which can facilitate integration with microdisplays, which may be flat panels, and can also facilitate manufacturing and provide high reproducibility and precision when forming nanolens arrays. For example, highly reproducible groove formation and deposition processes may be used to form each nanolens. Furthermore, these processes enable greater ease and reproducibility with respect to variations between nanolenses in the array than is typically achieved when forming curved lenses with similar variations.

[0305] Referring here to Figure 28, a perspective view of an embodiment of the light-emitting microdisplay 1030 is illustrated. It should be understood that the optical collimator array 1300 is advantageous in that it allows the light emitted from the microdisplay to be routed as desired. As a result, in some embodiments, the optical emitters of a full-color microdisplay can be organized as desired, for example, for ease of manufacturing or implementation within the display device. In some embodiments, the optical emitters 1044 may be arranged in rows or columns 1306a, 1306b, 1306c. Each row or column may include an optical emitter 1044 configured to emit light of the same primary color. In a display where three primary colors are utilized, there may be groups of three rows or columns, which are repeated across the microdisplay 1030. It should be understood that if more primary colors are utilized, each repeating group may have that number of rows or columns. For example, if four primary colors are used, each group may have four rows or four columns, where one row or one column is formed by a light emitter configured to emit light of a single primary color.

[0306] In some embodiments, some rows or columns may be repeated to increase the number of light emitters of a particular primary color. For example, some primary color light emitters may occupy multiple rows or columns. This may promote color balance and / or be used to address differential degradation or reduction in light emission intensity over time.

[0307] Referring to Figures 27 and 28, in some embodiments, each optical emitter 1044 may have an associated optical collimator 1302. In some other embodiments, each line 1306a, 1306b, 1306c of a plurality of optical emitters 1044 may have a single associated optical collimator 1302. That single associated optical collimator 1302 may extend substantially across the entire associated line 1306a, 1306b, or 1306c. In some other embodiments, the associated optical collimator 1302 may extend across a plurality of optical emitters 1044 that are extended and form part of the associated line 1306a, 1306b, or 1306c, and a plurality of similar optical collimators 1302 may be provided along each of the associated lines 1306a, 1306b, or 1306c.

[0308] Continuing with Figure 28, each optical emitter 1044 may be extended along a specific axis (e.g., along the y-axis, as shown). That is, each optical emitter has a length along a specific axis, and this length is greater than the width of the optical emitter. In addition, sets of optical emitters configured to emit light of the same primary color may be arranged in lines 1306a, 1306b, or 1306c (e.g., rows or columns) extending along an axis (e.g., the x-axis) that intersects (e.g., orthogonal) the extension axis of the optical emitters 1044. Thus, in some embodiments, optical emitters 1044 of the same primary color form lines 1306a, 1306b, or 1306c of optical emitters, the lines extending along a first axis (e.g., the x-axis), and the individual optical emitters 1044 within the lines are extended along a second axis (e.g., the y-axis).

[0309] In contrast, full-color microdisplays typically contain subpixels of each primary color, and the subpixels are arranged in a specific, relatively tightly packed spatial orientation within groups, and these groups are reproduced across the array. Each group of subpixels may form a pixel in the image. In some cases, the subpixels are stretched along an axis, and rows or columns of subpixels of the same primary color extend along that same axis. Such an arrangement allows the subpixels of each group to be located in close proximity to each other, which can have advantages in terms of image quality and pixel density. However, in the arrangement illustrated in Figure 28, the subpixels of different primary colors are relatively far apart due to the stretched shape of the light emitter 1044. In other words, the optical emitter of line 1306a is relatively far from the optical emitter of line 1306c because the elongated shape of the optical emitter of line 1306b separates the optical emitters 1306a and 1306c from the optical emitters in the vicinity of a given line of optical emitters. This could be expected to provide unacceptably poor image quality if the image formed on the surface of the microdisplay 1030 is relayed directly to the user's eye. However, the use of the optical collimator array 1300 is advantageous in that it allows different colored light to be routed as desired to form a high-quality image. For example, the light of each primary color may be used to form separate monochrome images, which are then routed to an eyepiece such as the eyepiece 1020 (e.g., Figures 11A and 12-14) and combined therein.

[0310] Referring to Figures 27 and 28, in some embodiments, each optical emitter 1044 may have an associated optical collimator 1302. In some other embodiments, each line 1306a, 1306b, 1306c of the optical emitter 1044 may have a single associated optical collimator 1302. That single associated optical collimator 1302 may extend substantially across the entire associated line 1306a, 1306b, or 1306c. In some other embodiments, the associated optical collimator 1302 may extend and span across multiple optical emitters 1044 that form part of the associated line 1306a, 1306b, or 1306c, and multiple similar optical collimators 1302 may be provided along each of the associated lines 1306a, 1306b, or 1306c.

[0311] It should be understood that the optical collimator 1302 may be used to direct light along different optical paths and form a multi-pupil projection system. For example, the optical collimator 1302 may direct light of different primary colors to two or three areas, respectively, in order to internally couple the light.

[0312] Figure 29 illustrates an embodiment of a wearable display system, comprising the full-color light-emitting microdisplay 1030 of Figure 28, used to form a multi-pupil projection system 1010. In the illustrated embodiment, the full-color light-emitting microdisplay 1030 emits three primary color lights to form a three-pupil projection system 1010. The projection system 1010 has three exit pupils through which image lights 1032a, 1032b, and 1032c of different primary colors propagate to three laterally shifted optical internal coupling elements 1022a, 1022b, and 1022c of the eyepiece 1020, respectively. The eyepiece 1020 then relays the image lights 1032a, 1032b, and 1032c to the user's eye 210.

[0313] The light-emitting microdisplay 1030 includes an array of light emitters 1044, which may be subdivided into monochrome light emitters 1044a, 1044b, and 1044c, each emitting image light 1032a, 1032b, and 1032c, respectively. It should be understood that the light emitters 1044 emit image light with a wide-angle emission profile 1046. The image light propagates through an array of light collimators 1300, which reduces the angle emission profile to a narrowed angle emission profile 1047.

[0314] In addition, the optical collimator array 1300 is configured to redirect the image light (image light 1032a, 1032b, 1032c) so that the image light is incident on the projection optical system 1070 at an angle that causes the projection optical system 1070 to output the image light, so that the image light propagates to the appropriate internally coupled optical elements 1022a, 1022b, and 1022c. For example, the optical collimator array 1300 is preferably configured to direct the image light 1032a so that it propagates through the projection optical system 1070 and incident on the internally coupled optical element 1022a, to direct the image light 1032b so that it propagates through the projection optical system 1070 and incident on the internally coupled optical element 1022b, and to direct the image light 1032c so that it propagates through the projection optical system 1070 and incident on the internally coupled optical element 1022c.

[0315] Since different optical emitters 1044 may emit light of different wavelengths and may need to be redirected in different directions to reach the appropriate internally coupled optical elements, in some embodiments, the optical collimators associated with different optical emitters 1044 may have different physical parameters (e.g., different pitch, different width, etc.). Advantageously, the use of planar nanolenses as optical collimators facilitates the formation of optical collimators with varying physical properties across the array 1300 of optical collimators. As described herein, the nanolenses may be formed using patterning and deposition processes, which facilitate the formation of structures with different pitches, widths, etc., across the substrate.

[0316] Referring again to Figure 24A, please note that the illustrated display system represents a single-emitting microdisplay, and the optical combiner 1050 (Figures 11A and 12-13B) is omitted. In embodiments utilizing the optical combiner 1050, the reflective surfaces 1052, 1054 (Figures 11A, 12-13B, and 30B) within the optical combiner 1050 are preferably specular reflectors, and it is expected that the light from the optical emitter 1044 will retain its large-angle emission profile after being reflected from the reflective surfaces 1052, 1054. Therefore, the problem of wasted light shown in Figure 24A is similar when the optical combiner 1050 is utilized.

[0317] Referring here to Figure 30A, an embodiment of a wearable display system is illustrated, comprising an emissive microdisplay and an associated array of optical collimators. Figure 30A shows additional details regarding the interaction between the optical emitter 1044, the optical collimator 1302, and the internally coupled optical elements of the eyepiece 1020. The display system includes a microdisplay 1030b, which in some embodiments may be a full-color microdisplay. In some other embodiments, the microdisplay 1030b may be a monochrome microdisplay, and additional monochrome microdisplays (not shown) may be provided on different faces of an optional optical combiner 1050 (as shown in Figure 30C).

[0318] Continuing with Figure 30A, the microdisplay 1030b includes an array of optical emitters 1044, each emitting light with a wide-angle emission profile (e.g., a Lambertian angular emission profile). Each optical emitter 1044 has an associated dedicated optical collimator 1302, which effectively narrows the angular emission profile to a narrowed angular emission profile 1047. The optical beams 1032b with the narrowed angular emission profiles pass through a projection optical system 1070, which projects or focuses those optical beams onto an internal coupling optical element 1022b. It should be understood that the optical beams 1032b have a certain cross-sectional shape and size 1047a. In some embodiments, the internal coupling optical element 1022b has a size and shape that substantially matches, or is larger than, the cross-sectional shape and size of the optical beams 1032b when the beams 1032b are incident on that internal coupling optical element 1022b. Therefore, in some embodiments, the size and shape of the internally coupled optical element 1022b may be selected based on the cross-sectional size and shape of the light beam 1032b when incident on the internally coupled optical element 1022b. In some other embodiments, other factors (such as re-bounce reduction or the angle or field of view supported by the internally coupled optical element 1022b) may be used to determine the size and shape of the internally coupled optical element 1022b, and the optical collimator 1302 may be configured (e.g., precisely sized and shaped) to provide a light beam 1032b with a appropriately sized and shaped cross-section that is completely or nearly completely encompassed by the size and shape of the internally coupled optical element 1022b. In some embodiments, the physical parameters for the optical collimator 1302 and the internally coupled optical element 1022b may be modified in conjunction with other desired functionalities (e.g., re-bounce reduction, support for a desired field of view, etc.) to provide highly efficient light utilization. Advantageously, the optical collimation provided by the optical collimator 1302, along with the matching of the cross-sectional size and shape of the optical beam 1032b with the size and shape of the internal coupling optical element 1022b, allows the internal coupling optical element 1022b to capture a large percentage of the incident optical beam 1032b.The internally coupled light then propagates through waveguide 1020b and is externally coupled to eye 210.

[0319] As shown in the figure, the microdisplay 1030b may comprise an array 1042 of optical emitters 1044, each surrounded by a non-emitting area 1045 having a total width 1045w. In addition, the optical emitters 1044 have a width W and a pitch P. In an array where the optical emitters 1044 are regularly spaced apart, each optical emitter 1044 and the surrounding area 1045 form a unit cell having a width 1045w, which may be practically equal to the pitch P.

[0320] In some embodiments, the optical collimator 1302 is a microlens positioned directly on and surrounding the associated optical emitter 1044. In some embodiments, the width of the microlens 1302 is equal to 1045w such that neighboring microlenses 1302 are in near or direct contact with each other. It should be understood that light from the optical emitter 1044 can fill the associated microlens 1302 and effectively enlarge the area encompassed by the optical emitter 1044. Advantageously, such a configuration reduces the perceptibility of area 1045, which does not emit light and would otherwise be visible to the user as a dark space. However, since the microlens 1302 effectively enlarges the associated optical emitter 1044 so as to extend across the entire area of ​​the microlens 1302, area 1045 may be masked.

[0321] Continuing with Figure 30A, the relative sizes of the optical emitter 1044 and the optical collimator 1302 may be selected to fill the optical collimator 1302 with which the light from the optical emitter 1044 is associated. For example, the optical emitter 1044 may be spaced far enough apart so that a microlens collimator 1302 having a desired curvature can be formed extending over each individual of the optical emitter 1044. In addition, as described above, the size and shape of the internal coupling optical element 1022b are preferably selected to match or exceed the cross-sectional shape and size of the light beam 1032b when incident on the internal coupling optical element 1022b. As a result, in some embodiments, the width 1025 of the internal coupling optical element 1022b is greater than or equal to the width of the microlens 1302 (which may have a width equal to 1045w or P). Preferably, the width 1025 exceeds the width or 1045w or P of the microlens 1302 to account for some diffusion of the light beam 1032b. As discussed herein, the width 1025 may also be selected to reduce re-bounce and may be shorter than the length (orthogonal to the width) of the internally coupled optical element 1022b. In some embodiments, the width 1025 may extend through the waveguide 1020b along the coaxial direction of propagation of the internally coupled light 1032b before being externally coupled for propagation to the eye 210.

[0322] Referring here to Figure 30B, embodiments of the optical projection system 1010 are illustrated, each comprising multiple light-emitting microdisplays 1030a, 1030b, and 1030c, and associated arrays 1300a, 1300b, and 1300c of optical collimators. The angular emission profiles of the light emitted by the microdisplays 1030a, 1030b, and 1030c are narrowed by the optical collimator arrays 1300a, 1300b, and 1300c, thereby facilitating the focusing of a large percentage of the light emitted by the projection optical system 1070 after the light has propagated through the optical combiner 1050. The projection optical system 1070 then directs the light towards an eyepiece such as an eyepiece 1020 (e.g., Figures 11A and 12-14) (not shown).

[0323] Figure 30C illustrates an embodiment of a wearable display system comprising a plurality of light-emitting microdisplays 1030a, 1030b, and 1030c, each accompanied by an associated array 1300a, 1300b, and 1300c, respectively, of which optical collimators are located. The illustrated display system includes a plurality of microdisplays 1030a, 1030b, and 1030c to emit light accompanied by image information. As illustrated, the microdisplays 1030a, 1030b, and 1030c may be microLED panels. In some embodiments, the microdisplays may be monochrome microLED panels, each configured to emit a different primary color. For example, microdisplay 1030a may be configured to emit red light 1032a, microdisplay 1030b may be configured to emit green light 1032b, and microdisplay 1030c may be configured to emit blue light 1032c.

[0324] Each microdisplay 1030a, 1030b, and 1030c may have associated arrays 1300a, 1300b, and 1300c of optical collimators, respectively. The optical collimators narrow the angular emission profiles of light 1032a, 1032b, and 1032c from the optical emitters of the associated microdisplays. In some embodiments, each individual optical emitter has its own associated optical collimator (as shown in Figure 30A).

[0325] Continuing with Figure 30C, the arrays of optical collimators 1300a, 1300b, and 1300c are located between the associated microdisplays 1030a, 1030b, and 1030c and the optical combiner 1050, which may be an X-cube. As shown, the optical combiner 1050 has internal reflective surfaces 1052 and 1054 to reflect incident light outward from the output surface of the optical combiner. In addition to narrowing the angular emission profile of the incident light, the arrays of optical collimators 1300a and 1300c may be configured to redirect light from the associated microdisplays 1030a and 1030c so that the light strikes the internal reflective surfaces 1052 and 1054 of the optical combiner 1050 at an appropriate angle for propagation toward the associated internal optical coupling elements 1022a and 1022c, respectively. In some embodiments, the optical collimator arrays 1300a, 1300c may be equipped with microlenses or reflective wells to redirect light in a specific direction, which may be asymmetrical, and / or the optical emitters may be positioned off-center relative to the microlenses or reflective wells, as disclosed herein.

[0326] Continuing with Figure 30C, the projection optical system 1070 (e.g., a projection lens) is positioned on the output surface of the optical combiner 1050 and receives the image light emitted from the optical combiner. The projection optical system 1070 may include a lens configured to focus or concentrate the image light onto the eyepiece 1020. As shown, the eyepiece 1020 may include a plurality of waveguides, each configured to internally and externally couple light of a specific color. For example, waveguide 1020a may be configured to receive red light 1032a from the microdisplay 1030a, waveguide 1020b may be configured to receive green light 1032b from the microdisplay 1030b, and waveguide 1020c may be configured to receive blue light 1032c from the microdisplay 1030c. Each waveguide 1020a, 1020b, and 1020c has associated optical internal coupling elements 1022a, 1022b, and 1022c, respectively, for internal coupling of light into it. In addition, as discussed herein, waveguides 1020a, 1020b, and 1020c may correspond to waveguides 670, 680, and 690 in Figure 9B, respectively, and may have associated orthogonal pupil expanders (OPEs) and exit pupil expanders (EPEs), which ultimately externally couple light 1032a, 1032b, and 1032c to the user.

[0327] As discussed herein, a wearable display system incorporating a microdisplay is preferably configured to emit light with varying amounts of wavefront divergence and to provide a comfortable near-or far-facing accommodative-convergence-divergence motion matching for the user. These varying amounts of wavefront divergence may be achieved using an external coupling optical element with varying refractive powers. As discussed herein, the external coupling optical element may be located on or within the waveguide of an eyepiece, such as eyepiece 1020 (e.g., Figures 11A and 12-14). In some embodiments, a lens may be used to increase the wavefront divergence provided by the external coupling optical element, or, in configurations where the external coupling optical element is configured to emit collimated light, it may be used to provide the desired wavefront divergence.

[0328] Figures 31A and 31B illustrate embodiments of eyepiece 1020 having lenses for varying the wavefront divergence of light to the viewer. Figure 31A illustrates eyepiece 1020 having a waveguide structure 1032. In some embodiments, as discussed herein, all primary color light may be internally coupled within a single waveguide, such that the waveguide structure 1032 contains only a single waveguide. This is advantageous as it provides a compact eyepiece. In some other embodiments, the waveguide structure 1032 may be understood to include multiple waveguides (e.g., waveguides 1032a, 1032b, and 1032c in Figures 11A and 12-13A), each configured to relay single primary color light to the user's eye.

[0329] In some embodiments, the variable focus lens elements 1530 and 1540 may be positioned on either side of the waveguide structure 1032. The variable focus lens elements 1530 and 1540 may be located in the path of image light from the waveguide structure 1032 to the eye 210, and also in the path of light from the ambient environment through the waveguide structure 1003 to the eye 210. The variable focus optical element 1530 can modulate the wavefront divergence of the image light output to the eye 210 by the waveguide structure 1032. It should be understood that the variable focus optical element 1530 may have refractive power that can distort the view of the world eye 210. As a result, in some embodiments, a second variable focus optical element 1540 may be provided on the world side of the waveguide structure 1032. The second variable-focus optical element 1540 may provide a refractive force opposite to that of the variable-focus optical element 1530 (or, if the waveguide structure 1032 has refractive power, opposite to that of the optical element 1530 and the waveguide structure 1032) such that the net refractive power of the variable-focus lens elements 1530, 1540 and the waveguide structure 1032 is substantially zero.

[0330] Preferably, the refractive power of the variable focus lens elements 1530, 1540 may be dynamically modified, for example, by applying an electrical signal thereto. In some embodiments, the variable focus lens elements 1530, 1540 may comprise a transmissive optical element such as a dynamic lens (e.g., a liquid crystal lens, an electroactive lens, a conventional refractive lens with a movable element, a mechanically deformable lens, an electrowetting lens, an elastomer lens, or a plurality of fluids with different refractive indices). The wavefront of the incident light may be changed by modifying the shape, refractive index, or other properties of the variable focus lens elements. In some embodiments, the variable focus lens elements 1530, 1540 may comprise a layer of liquid crystal sandwiched between two substrates. The substrates may comprise an optically transmissive material such as glass, plastic, or acrylic.

[0331] In some embodiments, in addition to providing a variable amount of wavefront divergence to position virtual content on different depth planes, or alternatively, the variable focus lens elements 1530, 1540 and waveguide structure 1032 may, advantageously, provide a net refractive power equal to the user's prescribed refractive power for a corrective lens. Thus, the eyepiece 1020 can serve as a substitute for a lens used to correct refractive errors, including myopia, hyperopia, presbyopia, and astigmatism. Further details regarding the use of variable focus lens elements as substitutes for corrective lenses can be found in U.S. Patent Application No. 15 / 481,255, filed April 6, 2017 (the entire disclosure thereof is incorporated herein by reference).

[0332] Referring here to Figure 31B, in some embodiments, the eyepiece 1020 may include a static lens element instead of a variable one. Similar to Figure 31B, the waveguide structure 1032 may include a single waveguide (e.g., capable of relaying light of different colors) or multiple waveguides (e.g., each capable of relaying light of a single primary color). Similarly, the waveguide structure 1034 may include a single waveguide (e.g., capable of relaying light of different colors) or multiple waveguides (e.g., each capable of relaying light of a single primary color). One or both of the waveguide structures 1032, 1034 may have refractive power and may output light with a specific amount of wavefront divergence, or may simply output collimated light.

[0333] Continuing with Figure 31B, the eyepiece 1020 may, in some embodiments, include static lens elements 1532, 1534, and 1542. Each of these lens elements is positioned in the path of light from the ambient environment through the waveguide structure 1032 and 1034 into the eye 210. In addition, lens element 1532 is located between the waveguide structure 10032 and the eye 210. Lens element 1532 corrects the wavefront divergence of the light output to the eye 210 by the waveguide structure 1032.

[0334] Lens element 1534 corrects the wavefront divergence of the light output to the eye 210 by waveguide structure 1034. It should be understood that the light from waveguide structure 1034 also passes through lens element 1532. Thus, the wavefront divergence of the light output by waveguide structure 1034 is corrected by both lens element 1534 and lens element 1532 (and waveguide structure 1032 if waveguide structure 1003 has refractive power). In some embodiments, lens elements 1532, 1534 and waveguide structure 1032 provide a specific net refractive power for the light output from waveguide structure 1034.

[0335] The illustrated embodiment provides two different levels of wavefront divergence, one for light emitted from waveguide structure 1032 and the second for light emitted from waveguide structure 1034. As a result, the virtual object can be positioned on two different depth planes corresponding to the different levels of wavefront divergence. In some embodiments, an additional level of wavefront divergence, and therefore an additional depth plane, may be provided by adding an additional lens element between the additional waveguide structure and the eye 210, and an additional waveguide structure between the lens element 1532 and the eye 210. Further levels of wavefront divergence may be added by adding further waveguide structures and lens elements.

[0336] Continuing to refer to Figure 31B, it should be understood that lens elements 1532, 1534 and waveguide structures 1032, 1034 provide a net refractive power that can distort the user's view of the world. As a result, lens element 1542 may be used to counteract the refractive power and distortion of ambient light. In some embodiments, the refractive power of lens element 1542 is set to neutralize the aggregate refractive power provided by lens elements 1532, 1534 and waveguide structures 1032, 1034. In some other embodiments, the net refractive power of lens elements 1542, 1532, 1534 and waveguide structures 1032, 1034 is equal to the user's prescribed refractive power for the corrective lens.

[0337] Referring here to Figures 11A-31B, it should be understood that any of the illustrated components of the wearable display system may be supported on the frame 80 (Figure 9E). Thus, each of these components may be effectively mounted on the user's head 90 as part of the wearable display system.

[0338] Various exemplary embodiments of the present invention are described herein. These embodiments are provided to illustrate broader and more applicable aspects of the present invention. Various modifications may be made to the described invention, and equivalents may be substituted without departing from the true spirit and scope of the invention.

[0339] For example, advantageously, it is used with an AR display that provides images across multiple depth planes, but the virtual content disclosed herein may also be displayed by a system that provides images on a single depth plane.

[0340] In addition, numerous modifications may be made to adapt specific circumstances, materials, material compositions, processes, process actions, or steps to the purpose, spirit, or scope of the present invention. Furthermore, as will be understood by those skilled in the art, each individual modification described and illustrated herein has discrete components and features that can be readily separated from or combined with features of any of several other embodiments without departing from the scope or spirit of the present invention. All such modifications are intended to be within the scope of the claims associated with this disclosure.

[0341] The present invention includes methods that can be carried out using the device of the subject matter. The methods may include the act of providing such a suitable device. Such provision may be carried out by an end user. In other words, the act of “providing” simply requires the user to act in such a way as to obtain, access, approach, position, configure, activate, power on, or otherwise provide the device required in the method of the subject matter. The methods enumerated herein may be carried out in any logically possible order of the enumerated events and in the enumerated order of the events.

[0342] Exemplary aspects of the present invention, along with details relating to material selection and manufacturing, are described above. Further details of the present invention are understood in relation to the patents and publications referenced above and are generally known or understandable to those skilled in the art. The same may apply to method-based embodiments of the present invention in terms of additional actions that may be generally or logically adopted.

[0343] In addition, although the present invention has been described with reference to several embodiments that optionally incorporate various features, the present invention is not limited to those described and indicated to be considered with respect to each modification of the present invention. Various modifications may be made to the described invention, and equivalents (whether listed herein or not included for some degree of brevity) may be substituted without departing from the true spirit and scope of the invention. In addition, where a range of values ​​is provided, it should be understood that all intermediate values ​​between the upper and lower limits of that range and any other stated values ​​or intermediate values ​​within the stated range are encompassed within the present invention.

[0344] Furthermore, it is considered that any optional features of the modified embodiments of the invention described herein may be described and claimed independently or in combination with any one or more of the features described herein. References to singular items include the possibility that there may be multiple identical items present. More specifically, as used herein and in the claims associated herein, the singular “a,” “an,” “said,” and “the” include multiple references unless otherwise specifically stated. In other words, the use of articles allows for “at least one” of the items of the subject matter in the above description and the claims associated with this disclosure. Furthermore, it should be noted that such claims may be drafted to exclude any optional elements. Thus, the language is intended to serve as an antecedent for the use of exclusive technical terms such as “simply,” “only,” and “equivalents,” or for the use of “negative” limitation, associated with the enumeration of elements of a claim.

[0345] Without using such exclusive terms, the term “~ comprising” in the claims associated with this disclosure shall allow for the inclusion of any additional elements, whether a given number of elements are enumerated in such claims or whether the addition of features can be considered a transformation of the properties of the elements described in such claims. Unless specifically defined herein, all technical and scientific terms used herein shall be given the broadest possible generally understood meaning while maintaining the validity of the claims.

Claims

1. A display system for presenting virtual image content to a user, wherein the display system is One or more light-emitting microdisplays, each of which comprises an array of light emitters corresponding to pixels, and the array of light emitters is configured to output image light defining the virtual image content, One or more collimating elements, each of which is arranged to at least partially collimate the image light output by one or more of the optical emitters, An eyepiece arranged to receive the at least partially collimated image light output from one or more collimating elements, wherein the eyepiece is configured to transmit the image light to the user's eye. Equipped with, A display system in which at least one of the one or more light-emitting microdisplays is arranged to emit the image light toward a reflective surface before the image light is directed toward the eyepiece, such that the image light is output along an optical path that is not at zero angle with respect to the normal to the surface of the eyepiece, and the eyepiece is configured to output the image light toward the user's eye with different amounts of wavefront divergence corresponding to different depth planes.

2. The display system according to claim 1, wherein at least one of the one or more light-emitting microdisplays is arranged to emit the image light toward the reflective surface before the image light is directed toward the eyepiece, such that the image light is output along an optical path that is at an angle of approximately 90 degrees with respect to the normal to the surface of the eyepiece.

3. The display system according to claim 1, wherein the array of light emitters is an array of microlight-emitting diodes (LEDs).

4. The display system according to claim 1, wherein the array of optical emitters is a two-dimensional array of optical emitters.

5. The display system according to claim 1, wherein at least one of the one or more light-emitting microdisplays is configured to output image light of multiple primary colors.

6. The display system according to claim 1, further comprising the reflective surface arranged to redirect the image light output by one or more light-emitting microdisplays toward the eyepiece.

7. The display system according to claim 6, wherein one or more collimating elements are arranged to receive the image light output by one or more of the optical emitters and to output the at least partially collimated image light toward the reflective surface.

8. The display system according to claim 6, wherein one or more collimating elements are arranged to receive the image light reflected from the reflective surface and to output the at least partially collimated image light toward the eyepiece.

9. The one or more collimating elements include one or more first collimating elements and a projection optical system. The one or more first collimating elements are arranged to receive the image light output by one or more of the optical emitters and to output the at least partially collimated image light toward the reflective surface. The display system according to claim 6, wherein the projection optical system is arranged to receive the image light reflected from the reflective surface, further collimate the reflected image light, and output it toward the eyepiece.

10. The eyepiece comprises a waveguide assembly having one or more waveguides, and each of the one or more waveguides is An internal coupling optical element configured to internally couple image light into the waveguide, An external coupling optical element configured to externally couple at least a portion of the internally coupled light out of the waveguide toward the user's eye, The display system according to claim 1, comprising:

11. A display system for presenting virtual image content to a user, wherein the display system is One or more light-emitting microdisplays, each of which comprises an array of light emitters corresponding to pixels, and the array of light emitters is configured to output image light defining the virtual image content, A plurality of first collimating elements, each of which is arranged to at least partially collimate the image light output by one of the optical emitters, An eyepiece arranged to receive the at least partially collimated image light output from the plurality of first collimating elements, wherein the eyepiece is configured to transmit the image light to the user's eye. Equipped with, A display system in which at least one of the one or more light-emitting microdisplays is arranged to emit the image light toward a reflective surface before the image light is directed toward the eyepiece, such that the image light is output along an optical path that is not at zero angle with respect to the normal to the surface of the eyepiece, and the eyepiece is configured to output the image light toward the user's eye with different amounts of wavefront divergence corresponding to different depth planes.

12. The display system according to claim 11, wherein at least one of the one or more light-emitting microdisplays is arranged to emit the image light toward the reflective surface before the image light is directed toward the eyepiece, such that the image light is output along an optical path that is at an angle of approximately 90 degrees with respect to the normal to the surface of the eyepiece.

13. The display system according to claim 11, wherein the array of light emitters is an array of microlight-emitting diodes (LEDs).

14. The display system according to claim 11, wherein the array of optical emitters is a two-dimensional array of optical emitters.

15. The display system according to claim 11, wherein at least one of the one or more light-emitting microdisplays is configured to output image light of multiple primary colors.

16. The display system according to claim 11, further comprising the reflective surface arranged to redirect the at least partially collimated image light output by the plurality of first collimating elements toward the eyepiece.

17. The display system according to claim 16, further comprising a projection optical system, wherein the projection optical system is arranged to receive the image light reflected from the reflective surface, further collimate the reflected image light, and output it toward the eyepiece.

18. The eyepiece comprises a waveguide assembly having one or more waveguides, and each of the one or more waveguides is An internal coupling optical element configured to internally couple image light into the waveguide, An external coupling optical element configured to externally couple at least a portion of the internally coupled light out of the waveguide toward the user's eye, The display system according to claim 11, comprising:

19. The display system according to claim 9, wherein the eyepiece includes a plurality of waveguides, each of which is configured to transmit the image light to the user's eye, each of which includes an internal coupling optical element for receiving the image light and internally coupling the image light into a separate waveguide, and the internal coupling optical elements of different waveguides are laterally offset from one another such that the internal coupling optical elements do not overlap at least partially when viewed from the projection optical system.

20. The display system according to claim 17, wherein the eyepiece includes a plurality of waveguides, each of which is configured to transmit the image light to the user's eye, each of which includes an internal coupling optical element for receiving the image light and internally coupling the image light into a separate waveguide, and the internal coupling optical elements of different waveguides are laterally offset from one another such that the internal coupling optical elements do not overlap at least partially when viewed from the projection optical system.

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