Display system and method for providing variable accommodation cues using multiple intra-pupil parallax views formed by light emitter arrays

Abstract

To provide a display system and a method for providing variable accommodation cues using multiple intra-pupil parallax views formed by light emitter arrays.SOLUTION: A display system is configured to direct a plurality of parallactically-disparate intra-pupil images into the viewer's eye. The parallactically-disparate intra-pupil images provide different parallax views of a virtual object, and impinge on the pupil from different angles. In the aggregate, wavefronts of light forming the images approximate a continuous divergent wavefront and provide selectable accommodation cues for a user, depending on an amount of parallax disparity between the intra-pupil images. The amount of parallax disparity may be selected using an array of shutters that selectively regulate entry of image light into the eye. Each opened shutter in the array provides a different intra-pupil image, and locations of the open shutters provide a desired amount of parallax disparity between the images.SELECTED DRAWING: None

Description

[Technical field]

[0001] (Priority Claim) This application claims priority to U.S. Provisional Application No. 62 / 812,142, filed February 28, 2019, and U.S. Provisional Application No. 62 / 815,225, filed March 7, 2019, which are incorporated by reference herein.

[0002] (Incorporated by reference) This application incorporates by reference the following patent applications and publications: U.S. Patent Application Publication No. 2018 / 0113311, published April 26, 2018; U.S. Patent Application No. 14 / 555,585, filed November 27, 2014; U.S. Patent Application No. 14 / 690,401, filed April 18, 2015; U.S. Patent Application No. 14 / 690,401, filed March 14, 2014; This application incorporates in its entirety each of U.S. Patent Application No. 14 / 212,961, filed July 14, 2014, U.S. Patent Application No. 14 / 331,218, filed March 16, 2016, and U.S. Patent Application No. WO2016 / 179246, published November 10, 2016, and U.S. Provisional Application No. 62 / 800363, filed February 1, 2019.

[0003] The present disclosure relates to optical devices, including augmented reality and virtual reality imaging and visualization systems. [Background technology]

[0004] Modern computing and display technologies have facilitated the development of systems for so-called "virtual reality" or "augmented reality" experiences in which digitally reproduced images or portions thereof are presented to a user in a manner that appears or may be perceived as real. Virtual reality, or "VR", scenarios typically involve the presentation of digital or virtual image information without transparency to other actual real-world visual inputs, and augmented reality, or "AR", scenarios typically involve the presentation of digital or virtual image information as an extension to the visualization of the real world around the user. Mixed reality, or "MR", scenarios are a type of AR scenario that typically involve virtual objects that are integrated into and responsive to the natural world. For example, in MR scenarios, AR image content may be perceived as appearing occluded by or otherwise interacting with objects in the real world.

[0005] 1, an augmented reality scene 10 is depicted in which a 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. In addition to these items, the user of the AR technology also perceives that they "see" "virtual content," such as a robotic figure 40 standing on the real-world platform 30 and a flying cartoon-like avatar character 50 that appears to be an anthropomorphic bumblebee, although these elements 50, 40 do not exist in the real world. The human visual perception system is complex, making it difficult to produce AR technology that facilitates a comfortable, natural-feeling, and rich presentation of virtual image elements among other virtual or real-world image elements.

[0006] The systems and methods disclosed herein address various challenges associated with AR or VR technology. Summary of the Invention [Means for solving the problem]

[0007] In some embodiments, a head mounted display system is provided. The display system includes an image projection system comprising a microdisplay configured to output image light defining an image, and projection optics configured to direct the image light from the microdisplay to a viewer's eye for propagation. The display system also comprises an array of selectively activated shutters to selectively transmit the image light from different locations to the eye. The array of selectively activated shutters is disposed within an eyebox volume of the projection optics.

[0008] In some other embodiments, a method for displaying image content is provided. The method includes projecting a set of parallaxically distinct intra-pupillary images of a virtual object into a viewer's eye from a head mounted display system. Each intra-pupillary image is provided by forming an image on a microdisplay of the head mounted display system, outputting image light from the microdisplay through the projection optics, and opening shutters of an array of shutters and propagating the image light through the opened shutters to the eye. The array of shutters is disposed within an eyebox volume of the projection optics. Different images of the set of parallaxically distinct intra-pupillary images propagate through different opened shutters.

[0009] In yet another embodiment, a head-mounted display system is provided. The display system comprises a microdisplay comprising an array of groups of light emitters, an array of light collimators on top of the light emitters, and projection optics. Each light collimator is associated with one of the groups of light emitters and extends across all light emitters of the associated group of light emitters. The array of light collimators is between the light emitters and the projection optics. The display system is configured to display a virtual object on a depth plane by projecting a set of parallax-distinct intra-pupillary images of the object into the viewer's eyes.

[0010] In some other embodiments, a method for displaying image content is provided, the method including projecting a set of parallaxically distinct intra-pupillary images into a viewer's eye from a head mounted display system, the projecting the set of parallaxically distinct intra-pupillary images including providing an array of groups of light emitters, providing an array of light collimators above the light emitters, each light collimator being associated with a group of light emitters, providing a projection optical system, the array of light collimators being between the array of groups of light emitters and the projection optical system, projecting a first parallaxically distinct intra-pupillary image into the eye by emitting light from a first light emitter of the group of light emitters, and projecting a second parallaxically distinct intra-pupillary image into the eye by emitting light from a second light emitter of the group of light emitters.

[0011] In addition, various innovative aspects of the subject matter described in this disclosure may be implemented in the following examples.

[0012] Example 1 1. A head mounted display system, comprising: 1. An image projection system, comprising: a microdisplay configured to output image light defining an image; a projection optical system configured to direct image light from the microdisplay to a viewer's eye for propagation; an image projection system comprising: an array of selectively activated shutters for selectively transmitting image light from different locations to the eye, the array of selectively activated shutters being disposed within an eyebox volume of the projection optics; A display system comprising:

[0013] Example 2 and a control system comprising one or more processors and a memory storing instructions that, when executed by the one or more processors, cause the display system to: Determining a desired depth plane for a virtual object; determining a shutter of the array of selectively activated shutters to be opened based on a desired depth plane; synchronizing the presentation of different images with the opening of different ones of the shutters by the image projection system, the different images providing different views of the virtual object; The display system according to example 1, which performs an operation including:

[0014] Example 3 3. The display system of any of Examples 1 or 2, wherein the shutter is a movable physical structure.

[0015] Example 4 The display system of example 3, wherein the physical structure is a MEMS-based micromechanical structure.

[0016] Example 5 The display system of example 3, wherein the shutter is a ferroelectric shutter.

[0017] Example 6 3. The display system of any of Examples 1 or 2, wherein the shutters comprise chemical species having reversibly changeable states, the states providing different amounts of light transmission.

[0018] Example 7 The display system of example 6, wherein the chemical species comprises liquid crystals and the shutters are formed by pixels of a pixelated liquid crystal display.

[0019] Example 8 The display system of any of Examples 1-7, wherein the microdisplay is an emissive microdisplay comprising an array of light emitters.

[0020] Example 9 The display system of example 8, wherein the light emitter is a micro LED.

[0021] Example 10 The display system of any of Examples 1-9, further comprising an array of light collimators between the light emitter and the projection optics.

[0022] Example 11 11. The display system of embodiment 10, wherein the arrays of light collimators each extend across the plurality of light emitters, and each light collimator corresponds to a pixel in an image output by the image projection system.

[0023] Example 12 A display system described in any of Examples 1-11, wherein the microdisplay is one of a plurality of monochrome microdisplays forming a projection system, each of the monochrome microdisplays being configured to emit light of a different primary color.

[0024] (Example 13) 13. The display system of example 12, further comprising an X-cube prism, wherein each of the monochrome microdisplays is arranged to output image light into a different face of the X-cube prism.

[0025] Example 14 A display system as described in any of Examples 1-13, further comprising a pupil relay combiner eyepiece configured to relay image light to a viewer's eye, and an array of selectively activated shutters configured to adjust propagation of the image light to the pupil relay combiner eyepiece.

[0026] Example 15 The pupil relay combiner eyepiece comprises a waveguide, the waveguide comprising: an incoupling optical element for incoupling the image light into the waveguide; an outcoupling optical element for outcoupling the incoupled image light out of the waveguide; The display system of Example 14, comprising:

[0027] (Example 16) 16. The display system of example 15, wherein the waveguide is one of a plurality of waveguides comprising an in-coupling optical element and an out-coupling optical element.

[0028] (Example 17) The display system according to any one of Examples 1-16, wherein the projection system has a pupil diameter of 0.2 to 0.5 mm.

[0029] (Example 18) 1. A method for displaying image content, the method comprising: Presenting a set of parallax-distinct intrapupillary images of a virtual object into the viewer's eyes from a head-mounted display system. Including, Each image in the pupil image is forming an image on a microdisplay of a head mounted display system; Outputting image light from the microdisplay through a projection optical system; opening shutters of an array of shutters and transmitting the image light through the opened shutters to the eye, the array of shutters being positioned within an eyebox volume of the projection optics; Provided by A method in which different images of a set of parallaxly distinct intrapupillary images are propagated through different opened shutters.

[0030] (Example 19) 20. The method of example 18, wherein all images of the set of parallaxly distinct intrapupillary images are injected into the eye within the flicker fusion threshold.

[0031] (Example 20) 19. The method of embodiment 18, wherein the flicker fusion threshold is 1 / 60 seconds.

[0032] Example 21 determining a desired depth plane for a virtual object to be displayed to a viewer; determining a shutter of the array of selectively activated shutters to be opened based on a desired depth plane; Synchronizing the presentation of different sets of parallax-distinct intrapupillary images with the opening of different shutters; The method of any of Examples 18-20, further comprising:

[0033] Example 22 determining a line of sight of the eye using an eye tracking sensor; selecting content for an intrapupillary image based on the determined line of sight of the eye; The method of any of Examples 18-21, further comprising:

[0034] (Example 23) The method of any of Examples 18-22, wherein the microdisplay is an emissive microdisplay.

[0035] Example 24 24. The method of any of Examples 18-23, wherein the array of shutters comprises a selectively movable physical structure.

[0036] (Example 25) The method of any of Examples 18-23, wherein the array of shutters comprises chemical species having reversibly changeable states, the states providing different amounts of light transmission.

[0037] (Example 26) 26. The method of any of Examples 18-25, wherein the different images provide different views of the virtual object.

[0038] Example 27 1. A head mounted display system, comprising: a microdisplay comprising an array of groups of light emitters; an array of optical collimators on top of the optical emitters, each optical collimator being associated with one of the groups of optical emitters and extending across all optical emitters of the associated group of optical emitters; a projection optical system, the array of optical collimators being between the optical emitter and the projection optical system; Equipped with The display system is configured to display virtual objects on a depth plane by projecting a set of parallax-distinct intra-pupillary images of the objects into a viewer's eyes.

[0039] (Example 28) and one or more processors and memory storing instructions, which when executed by the one or more processors, cause the display system to: determining a respective light emitter of the group of light emitters to activate based on a desired level of parallax difference for an image formed by the light emitter; activating a first light emitter of the group of light emitters to form a first parallaxically distinct intrapupillary image; activating a second light emitter of the group of light emitters to form a second parallaxically distinct intrapupillary image; Performing an operation including 28. The display system of example 27, wherein the first and second parallaxically distinct intrapupillary images provide different views of a virtual object.

[0040] (Example 29) The display system of Example 27, wherein activating a first light emitter of the group of light emitters overlaps in time with activating a second light emitter of the group of light emitters to simultaneously project first and second parallaxically distinct intrapupillary images into the eye.

[0041] (Example 30) The display system of any of Examples 27-29, wherein the light collimator is a lenslet.

[0042] (Example 31) An array of selectively activated shutters for selectively transmitting image light from different locations to the eye, the array of selectively activated shutters being disposed within an eyebox volume of the projection optics. The display system of any of Examples 27-30, further comprising:

[0043] Example 32 32. The display system of example 31, wherein the array of shutters comprises selectively movable physical structures.

[0044] (Example 33) 32. The display system of example 31, wherein the array of shutters comprises chemical species having reversibly changeable states, the states providing different amounts of light transmission.

[0045] (Example 34) and one or more processors and memory storing instructions, which when executed by the one or more processors, cause the display system to: Determining a desired depth plane for a virtual object; determining a shutter of the array of selectively activated shutters to be opened based on a desired depth plane; synchronizing the presentation of different images and the opening of different ones of the shutters by the image projection system, the different images providing different views of the virtual object; A display system as described in any one of Examples 31-33, which performs an operation including:

[0046] (Example 35) the light collimators are lenticular lenslets configured to provide different beams of light from the light emitters of an associated group of light emitters to different locations along a first axis; A display system as described in any of Examples 27-34, wherein the array of shutters is arranged to form a sub-pupil along a second axis orthogonal to the first axis.

[0047] (Example 36) The display system of any of Examples 27-35, wherein the microdisplay is an emissive microdisplay and the light emitter is a microLED.

[0048] (Example 37) A display system described in any of Examples 27-36, wherein the microdisplay is one of a plurality of monochrome microdisplays, each of which is configured to emit light of a different primary color.

[0049] (Example 38) 38. The display system of Example 37, further comprising an X-cube prism, wherein each of the monochrome microdisplays is arranged to output image light into a different face of the X-cube prism.

[0050] (Example 39) A display system as described in any of Examples 27-38, further comprising a pupil relay combiner eyepiece configured to relay image light to a viewer's eye, and an array of selectively activated shutters configured to adjust propagation of image light to the pupil relay combiner eyepiece.

[0051] (Example 40) The pupil relay combiner eyepiece comprises a waveguide, the waveguide comprising: an incoupling optical element for incoupling the image light into the waveguide; an outcoupling optical element for outcoupling the incoupled image light out of the waveguide; The display system of Example 39, comprising:

[0052] (Example 41) 41. The display system of embodiment 40, wherein the waveguide is one of a plurality of waveguides comprising an internal coupling optical element and an external coupling optical element.

[0053] (Example 42) 1. A method for displaying image content, the method comprising: presenting a set of parallax-distinct intrapupillary images into a viewer's eyes from a head mounted display system; Injecting a set of disparity-disparate intra-pupil images Providing an array of groups of light emitters; providing an array of optical collimators on top of the optical emitters, each optical collimator being associated with a group of optical emitters; providing a projection optical system, the array of optical collimators being between the array of groups of optical emitters and the projection optical system; projecting a first parallaxically distinct intrapupillary image into the eye by emitting light from a first light emitter of the group of light emitters; projecting a second parallaxically distinct intrapupillary image into the eye by emitting light from a second light emitter of the group of light emitters. A method comprising:

[0054] (Example 43) 43. The method of example 42, wherein each image of the set of parallaxically distinct intra-pupillary images is injected into the eye at a different angle, and all images of the set of parallaxically distinct intra-pupillary images are injected into the eye within a flicker fusion threshold.

[0055] (Example 44) 44. The method of embodiment 43, wherein the flicker fusion threshold is 1 / 60 seconds.

[0056] (Example 45) 44. The method of any of Examples 42-43, wherein the different images provide different views of the virtual object.

[0057] (Example 46) 46. ​​The method of any of Examples 42-45, wherein the introducing of the first parallaxically distinct intrapupillary image and the introducing of the second parallaxically distinct intrapupillary image are performed simultaneously.

[0058] (Example 47) providing an array of selectively activated shutters for selectively transmitting image light from different locations to the eye, the array of selectively activated shutters being positioned within an eyebox volume of the projection optics; The method of any of Examples 42-46, further comprising:

[0059] (Example 48) A method according to any of Examples 42-47, wherein the light collimator is a lenticular lenslet configured to provide different beams of light from light emitters of an associated group of light emitters to different locations along a first axis, and the array of shutters is arranged to form a sub-pupil along a second axis orthogonal to the first axis.

[0060] (Example 49) The method of any of Examples 47-48, further comprising spatially multiplexing a plurality of images formed by different light emitters of a group of light emitters, positioning a display sub-pupil along a first axis, and temporally multiplexing the plurality of images by synchronizing the opening of a shutter with the activation of a corresponding light emitter.

[0061] (Example 50) 50. The method of any of Examples 47-49, wherein the array of shutters comprises a selectively movable physical structure.

[0062] (Example 51) The method of any of Examples 47-49, wherein the array of shutters comprises chemical species having reversibly changeable states, the states providing different amounts of light transmission.

[0063] (Example 52) The method of any of Examples 42-51, wherein injecting a first parallaxically distinct intra-pupillary image and injecting a second parallaxically distinct intra-pupillary image include routing light from the light emitter through a pupil relay combiner eyepiece to the eye.

[0064] (Example 53) The pupil relay combiner eyepiece comprises a waveguide, the waveguide comprising: an incoupling optical element for incoupling the image light into the waveguide; an outcoupling optical element for outcoupling the incoupled image light out of the waveguide; The method of Example 52, comprising:

[0065] (Example 54) The method of any of Examples 42-53, further comprising projecting a second set of parallaxically distinct intrapupillary images into a second eye of the viewer from a head mounted display system. The present invention provides, for example, the following: (Item 1) 1. A head mounted display system, comprising: 1. An image projection system, comprising: a microdisplay configured to output image light defining an image; a projection optical system configured to direct image light from the microdisplay to a viewer's eye for propagation; an image projection system comprising: an array of selectively activated shutters for selectively transmitting the image light from different locations to the eye, the array of selectively activated shutters being disposed within an eyebox volume of the projection optics; and A display system comprising: (Item 2) and a control system comprising one or more processors and a memory storing instructions that, when executed by the one or more processors, cause the display system to: Determining a desired depth plane for a virtual object; determining which shutters of the array of selectively activated shutters should be opened based on the desired depth plane; synchronizing the presentation of different images by the image projection system with the opening of different ones of the shutters, the different images providing different views of the virtual object; 2. The display system of claim 1, further comprising: (Item 3) Item 2. The display system of item 1, wherein the shutter is a movable physical structure. (Item 4) 4. The display system of item 3, wherein the physical structure is a MEMS-based micromechanical structure. (Item 5) Item 4. The display system of item 3, wherein the shutter is a ferroelectric shutter. (Item 6) Item 13. The display system of item 1, wherein the shutter comprises a chemical species having reversibly changeable states, the states providing different amounts of light transmission. (Item 7) 7. The display system of claim 6, wherein the chemical species comprises liquid crystals and the shutters are formed by pixels of a pixelated liquid crystal display. (Item 8) 2. The display system of claim 1, wherein the microdisplay is an emissive microdisplay comprising an array of light emitters. (Item 9) 9. The display system of claim 8, wherein the light emitter is a micro LED. (Item 10) 9. The display system of item 8, further comprising an array of light collimators between the light emitter and the projection optics. (Item 11) Item 11. A display system as described in item 10, wherein the arrays of light collimators each extend across a plurality of the light emitters, and each light collimator corresponds to a pixel in an image output by the image projection system. (Item 12) 2. The display system of claim 1, wherein the microdisplay is one of a plurality of monochrome microdisplays forming the projection system, each of the monochrome microdisplays being configured to emit light of a different primary color. (Item 13) Item 13. The display system of item 12, further comprising an X-cube prism, each of the monochrome microdisplays being arranged to output image light into a different face of the X-cube prism. (Item 14) 2. The display system of claim 1, further comprising a pupil relay combiner eyepiece configured to relay the image light to the viewer's eye, and the array of selectively activated shutters configured to adjust propagation of the image light to the pupil relay combiner eyepiece. (Item 15) The pupil relay combiner eyepiece comprises a waveguide, the waveguide comprising: an incoupling optical element for incoupling the image light into the waveguide; an outcoupling optical element for outcoupling the incoupled image light out of the waveguide; Item 15. The display system of item 14, comprising: (Item 16) Item 16. The display system of item 15, wherein the waveguide is one of a plurality of waveguides comprising an internal coupling optical element and an external coupling optical element. (Item 17) Item 2. The display system of item 1, wherein the projection system has a pupil diameter of 0.2 to 0.5 mm. (Item 18) 1. A method for displaying image content, the method comprising: Presenting a set of parallax-distinct intrapupillary images of a virtual object into the viewer's eyes from a head-mounted display system. Including, Each of the intrapupillary images is forming said image on a micro-display of said head mounted display system; outputting image light from the microdisplay through a projection optical system; opening shutters of an array of shutters and transmitting image light through the opened shutters to the eye, the array of shutters being positioned within an eyebox volume of the projection optical system; Provided by A method in which different images of a set of parallaxly distinct intrapupillary images are propagated through different opened shutters. (Item 19) 20. The method of claim 18, wherein all images of a set of parallaxly distinct intrapupillary images are injected into the eye within a flicker fusion threshold. (Item 20) 20. The method of claim 18, wherein the flicker fusion threshold is 1 / 60 seconds. (Item 21) determining a desired depth plane for the virtual object to be displayed to the viewer; determining which shutters of the array of selectively activated shutters should be opened based on the desired depth plane; synchronizing the presentation of different ones of a set of parallax-distinct intrapupillary images with the opening of different ones of said shutters; 20. The method of claim 18, further comprising: (Item 22) determining a line of sight of the eye using an eye tracking sensor; selecting content for the intrapupillary image based on the determined line of sight of the eye; 20. The method of claim 18, further comprising: (Item 23) Item 19. The method of item 18, wherein the microdisplay is an emissive microdisplay. (Item 24) Item 19. The method of item 18, wherein the array of shutters comprises a selectively moveable physical structure. (Item 25) 20. The method of claim 18, wherein the array of shutters comprises chemical species having reversibly changeable states, the states providing different amounts of light transmission. (Item 26) Item 19. The method of item 18, wherein the different images provide different views of the virtual object. (Item 27) 1. A head mounted display system, comprising: a microdisplay comprising an array of groups of light emitters; an array of optical collimators on top of the light emitters, each optical collimator being associated with one of the groups of light emitters and extending across all the light emitters of the associated group of light emitters; a projection optical system, the array of optical collimators being between the optical emitter and the projection optical system; Equipped with The display system is configured to display a virtual object on a depth plane by projecting a set of parallaxly distinct intra-pupillary images of the object into a viewer's eyes. (Item 28) and one or more processors and a memory storing instructions that, when executed by the one or more processors, cause the display system to: determining a respective light emitter of the group of light emitters for activation based on a desired level of parallax difference for an image formed by the light emitter; activating a first light emitter of the group of light emitters to form a first parallaxically distinct intrapupillary image; activating a second light emitter of said group of light emitters to form a second parallaxically distinct intrapupillary image; Performing an operation including Item 28. The display system of item 27, wherein the first and second parallaxically distinct intrapupillary images provide different views of the virtual object. (Item 29) 28. The display system of claim 27, wherein activating a first light emitter of the group of light emitters overlaps in time with activating a second light emitter of the group of light emitters to simultaneously project the first and second parallaxically distinct intrapupillary images into the eye. (Item 30) Item 28. The display system of item 27, wherein the light collimator is a lenslet. (Item 31) an array of selectively activated shutters for selectively transmitting the image light from different locations to the eye, the array of selectively activated shutters being disposed within an eyebox volume of the projection optical system. 28. The display system of claim 27, further comprising: (Item 32) Item 32. The display system of item 31, wherein the array of shutters comprises a selectively movable physical structure. (Item 33) 32. The display system of claim 31, wherein the array of shutters comprises chemical species having reversibly changeable states, the states providing different amounts of light transmission. (Item 34) and one or more processors and a memory storing instructions that, when executed by the one or more processors, cause the display system to: Determining a desired depth plane for a virtual object; determining which shutters of the array of selectively activated shutters should be opened based on the desired depth plane; synchronizing the presentation of different images by the image projection system with the opening of different ones of the shutters, the different images providing different views of the virtual object; 32. The display system of claim 31, further comprising: (Item 35) the light collimators being lenticular lenslets configured to provide different beams of light from light emitters of an associated group of the light emitters to different locations along a first axis; Item 28. The display system of item 27, wherein the array of shutters is arranged to form a sub-pupil along a second axis orthogonal to the first axis. (Item 36) 28. The display system of claim 27, wherein the microdisplay is an emissive microdisplay and the light emitter is a microLED. (Item 37) Item 28. The display system of item 27, wherein the microdisplay is one of a plurality of monochrome microdisplays, each of the monochrome microdisplays configured to emit light of a different primary color. (Item 38) Item 38. The display system of item 37, further comprising an X-cube prism, each of the monochrome microdisplays being arranged to output image light into a different face of the X-cube prism. (Item 39) 28. The display system of item 27, further comprising a pupil relay combiner eyepiece configured to relay the image light to the viewer's eye, and an array of selectively activated shutters configured to adjust propagation of the image light to the pupil relay combiner eyepiece. (Item 40) The pupil relay combiner eyepiece comprises a waveguide, the waveguide comprising: an incoupling optical element for incoupling the image light into the waveguide; an outcoupling optical element for outcoupling the incoupled image light out of the waveguide; 40. The display system of item 39, comprising: (Item 41) Item 41. The display system of item 40, wherein the waveguide is one of a plurality of waveguides comprising an in-coupling optical element and an out-coupling optical element. (Item 42) 1. A method for displaying image content, the method comprising: Presenting a set of parallax-distinct intrapupillary images into the viewer's eyes from a head-mounted display system. Including, The inputting of the set of disparity-disparate intrapupillary images comprises: Providing an array of groups of light emitters; providing an array of optical collimators above the optical emitters, each optical collimator being associated with a group of the optical emitters; providing a projection optical system, the array of optical collimators being between the array of groups of optical emitters and the projection optical system; projecting a first parallaxically distinct intrapupillary image into the eye by emitting light from a first light emitter of the group of light emitters; projecting a second parallaxically distinct intrapupillary image into the eye by emitting light from a second light emitter of the group of light emitters; A method comprising: (Item 43) Item 43. The method of item 42, wherein each image in the set of parallaxly distinct intra-pupillary images is projected into the eye at a different angle, and all images in the set of parallaxly distinct intra-pupillary images are projected into the eye within a flicker fusion threshold. (Item 44) Item 44. The method of item 43, wherein the flicker fusion threshold is 1 / 60 seconds. (Item 45) Item 43. The method of item 42, wherein the different images provide different views of the virtual object. (Item 46) 43. The method of claim 42, wherein the applying of the first parallaxically distinct intrapupillary image and the applying of the second parallaxically distinct intrapupillary image are performed simultaneously. (Item 47) providing an array of selectively activated shutters for selectively transmitting the image light from different locations to the eye, the array of selectively activated shutters being positioned within an eyebox volume of the projection optics; 43. The method of claim 42, further comprising: (Item 48) Item 48. The method of item 47, wherein the light collimator is a lenticular lenslet configured to provide different beams of light from light emitters of an associated group of the light emitters to different locations along a first axis, and the array of shutters is arranged to form a sub-pupil along a second axis orthogonal to the first axis. (Item 49) Item 49. The method of item 48, further comprising: spatially multiplexing a plurality of images formed by different light emitters of the group of light emitters; positioning a display sub-pupil along the first axis; and temporally multiplexing the plurality of images by synchronizing the opening of a shutter with the activation of a corresponding light emitter. (Item 50) Item 48. The method of item 47, wherein the array of shutters comprises a selectively moveable physical structure. (Item 51) Item 48. The method of item 47, wherein the array of shutters comprises chemical species having reversibly changeable states, the states providing different amounts of light transmission. (Item 52) Item 43. The method of item 42, wherein injecting the first parallaxically distinct intra-pupillary image and injecting the second parallaxically distinct intra-pupillary image include routing light from the light emitter to the eye through a pupil relay combiner eyepiece. (Item 53) The pupil relay combiner eyepiece comprises a waveguide, the waveguide comprising: an incoupling optical element for incoupling the image light into the waveguide; an outcoupling optical element for outcoupling the incoupled image light out of the waveguide; 53. The method of claim 52, comprising: (Item 54) Item 43. The method of item 42, further comprising projecting a second set of parallaxly distinct intrapupillary images from the head mounted display system into a second eye of the viewer. [Brief description of the drawings]

[0066] [Figure 1] FIG. 1 illustrates a user's view of an augmented reality (AR) device.

[0067] [Diagram 2] FIG. 2 illustrates a conventional scheme for simulating a three-dimensional image for a user.

[0068] [Diagram 3] FIG. 3 illustrates aspects of an approach for simulating a three-dimensional image using multiple depth planes.

[0069] [Figure 4] 4A-4C illustrate the relationship between wavefront curvature and focal length.

[0070] [Diagram 5] FIG. 5 illustrates an embodiment of a waveguide stack for outputting image information to a user.

[0071] [Figure 6A] FIG. 6A illustrates the pre-accommodation and post-accommodation states of the eye for a continuous incident wavefront.

[0072] [Figure 6B] FIG. 6B illustrates the pre-accommodation and post-accommodation states of the eye for a piecewise approximation for a continuous incident wavefront.

[0073] [Figure 7A] FIG. 7A illustrates the eye accommodating to a diverging wavefront emanating from a finite focal length virtual image provided by a projection system.

[0074] [Figure 7B] FIG. 7B illustrates a system for forming an approximation of the diverging wavefront of FIG. 7A utilizing wavefront segments formed by infinity-focused virtual images.

[0075] [Figure 8] FIG. 8 illustrates an example of parallax views forming the diverging wavefront approximation of FIG. 7B.

[0076] [Figure 9] FIG. 9 illustrates an example of a display system that includes a projection system for forming the diverging wavefront approximations of FIGS.

[0077] [Figure 10] 10A-10C illustrate an embodiment of an array of shutters for providing different parallax views.

[0078] [Figure 11] FIG. 11 illustrates an embodiment of the projection system of FIG. 9 that provides different parallaxically distinct intrapupillary images at different times than those shown in FIG.

[0079] [Figure 12] FIG. 12 illustrates an embodiment of the projection system of FIGS. 9 and 11 with an array of optical collimators between the emissive microdisplay and the projection optics.

[0080] [Figure 13] FIG. 13 illustrates another embodiment of a display system that includes a projection system for forming the diverging wavefront approximation of FIGS.

[0081] [Figure 14] FIG. 14 illustrates an example of a projection system having an array of optical collimators and an array of shutters for forming different parallax-different intra-pupillary images.

[0082] [Figure 15] FIG. 15 illustrates an example of a range of depth planes provided by a projection system, according to various embodiments.

[0083] [Figure 16A] FIG. 16A illustrates an example of a display system comprising a projection system comprising an array of shutters and a pupil relay combiner eyepiece for superimposing image content onto a user's view of the world.

[0084] [Figure 16B]FIG. 16B illustrates an example of a display system comprising a projection system comprising an array of optical collimators to provide different intra-pupillary images and a pupil relay combiner eyepiece to superimpose the image content onto the user's view of the world.

[0085] [Figure 17A] FIG. 17A illustrates another example of a display system comprising a projection system comprising an array of shutters and a pupil relay combiner eyepiece for superimposing image content onto a user's view of the world.

[0086] [Figure 17B] FIG. 17B illustrates another example of a display system comprising a projection system comprising an array of optical collimators to provide different intra-pupillary images and a pupil relay combiner eyepiece to superimpose the image content onto the user's view of the world.

[0087] [Figure 18] FIG. 18 illustrates an example of a display system including an eye tracking system and a combiner eyepiece with a pupil expander.

[0088] [Figure 19] FIG. 19 illustrates an example of a display system comprising an eye tracking system and a pupil relay combiner eyepiece with a pupil expander configured to produce a non-infinite depth plane.

[0089] [Figure 20] 20A-20B illustrate an embodiment of a projection system having multiple microdisplays.

[0090] [Figure 21] FIG. 21 illustrates an example of an eyepiece with stacked waveguide assemblies for outputting different wavelengths of light corresponding to different primary colors.

[0091] [Figure 22] FIG. 22 illustrates an example of a wearable display system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0092] The human visual system can be made to perceive an image presented by a display as being "three-dimensional" by providing a slightly different presentation of the image to each of the viewer's left and right eyes. Depending on the image presented to each eye, the viewer perceives the "virtual" object in the image as being at a selected distance (e.g., a "depth plane") from the viewer (also referred to herein as the "user"). However, simply providing different presentations of the image to the left and right eyes may cause discomfort to the viewer. As discussed further herein, viewing comfort can be increased by having the eye accommodate to an image in which the eye would accommodate a real object in the depth plane in which the virtual object is located.

[0093] Appropriate accommodation for a virtual object on a given depth plane can be induced by presenting an image to the eye with light having a wavefront divergence that matches the wavefront divergence of light resulting from a real object on that depth plane. Some display systems use distinct structures with distinct refractive powers to provide the appropriate wavefront divergence. For example, one structure may provide a specific amount of wavefront divergence (for placing a virtual object on one depth plane) and another structure may provide a different amount of wavefront divergence (for placing a virtual object on a different depth plane). Thus, there may be a one-to-one correspondence between physical structures and depth planes in these display systems. Due to the need for a separate structure for each depth plane, such display systems may be bulky and / or heavy, which may not be desirable for some applications, such as portable head-mounted displays. In addition, such display systems may be limited in the number of different accommodative responses they can evoke from the eye due to practical limitations on the number of structures of different refractive powers that may be utilized.

[0094] It has been found that a continuous wavefront, e.g., a continuous diverging wavefront, can be approximated by injecting parallax-distinct intra-pupillary images directed into the eye. For example, a display system may provide a range of accommodative responses without requiring a one-to-one correspondence between the accommodative response and the optical structures in the display. The display system may output light with a selected amount of perceived wavefront divergence corresponding to a desired depth plane by injecting a set of parallax-distinct intra-pupillary images into the eye. These images may be referred to as "parallax-distinct" intra-pupillary images because each image may be considered to be a different parallax view of the same virtual object or scene on a given depth plane. These are "intra-pupillary" images because a set of images bearing parallax differences are projected into the pupil of one eye, e.g., the right or left eye of the viewer. The images may have some overlap, but the light beams forming these images will have at least some areas with no overlap and will impinge on the pupil from slightly different angles. In some embodiments, the viewer's other eye, e.g., the left eye, may be provided with its own set of parallaxically distinct intra-pupillary images. The set of parallaxically distinct intra-pupillary images projected into each eye may be slightly different, e.g., the images may show slightly different views of the same scene due to the slightly different perspectives provided by each eye.

[0095] The wavefronts of light forming each of the intrapupillary images of the different views may collectively approximate a continuous diverging wavefront when projected into the pupil of the eye. The amount of perceived divergence of this approximated wavefront may be varied by varying the disparity difference between the intrapupillary images, i.e., changing the disparity difference changes the angular range spanned by the wavefronts of light forming the intrapupillary images. Preferably, this angular range mimics the angular range spanned by the continuous wavefront being approximated. In some embodiments, the wavefronts of light forming the individual intrapupillary images are collimated or quasi-collimated as discussed herein. An example of a system for providing intrapupillary images is disclosed in U.S. Application Publication No. 2018 / 0113311, published April 26, 2018. Some embodiments disclosed in that application utilize light emitters to illuminate a spatial light modulator, which encodes the light from the light emitters with image information; i.e., multiple light emitters may be provided and different intra-pupillary images may be formed at different locations using the light emitters to provide a desired amount of parallax difference between the images.

[0096] Preferably, the set of intrapupillary images for approximating a particular continuous wavefront are launched into the eye rapidly enough that the human visual system does not detect that the images were presented to the eye at different times. Without being limited by theory, the term "flicker fusion threshold" may be used to indicate a duration during which images presented to the human eye are perceived as being presented simultaneously, i.e., the visual system may perceive images formed on the retina within the flicker fusion threshold as being presented simultaneously. In some embodiments, approximating a continuous wavefront may include launching a beam of light into the eye sequentially for each set of intrapupillary images, with the total duration for launching all of the beams of light being less than the flicker fusion threshold. It should be understood that presenting a set of images for a duration that exceeds the flicker fusion threshold may result in the human visual system perceiving at least some of the images as being launched separately into the eye. By way of example, the flicker fusion threshold may be approximately 1 / 60th of a second. As a result, each set of intra-pupillary images may consist of a certain number of disparity views, e.g., two or more views, three or more views, four or more views, etc., preferably all of which are presented to the eye within the flicker fusion threshold.

[0097] Providing all of the desired views within the flicker fusion threshold presents a challenge for some display technologies, such as those that use spatial light modulators, in which physical elements are moved to modulate the intensity of the output light. The need to physically move these elements can limit the speed at which individual pixels can change state and also constrain the frame rate of displays using these optical elements. In addition, spatial light modulators can require a separate light source, which can undesirably add complexity, size, and weight to the display system and potentially limit the brightness of the displayed image.

[0098] In some embodiments, the display system includes an emissive microdisplay, which can advantageously provide different intrapupillary images at a significantly higher rate. In addition, the display system may include an array of shutters. The shutters of the array of shutters may be individually selectively opened or activated to allow light transmission, allowing light to propagate into the retina from different locations. The emissive microdisplay emits image light to form the intrapupillary image, and the image light propagates to the array of shutters. Different ones of the shutters at different locations may be selectively opened (made transparent to the image light) to allow the image light to propagate further into the viewer's eye from those different locations. The amount of parallax difference between the intrapupillary images may be varied by changing the locations where the shutters are opened. As a result, spatial differences in the open shutter locations may be translated into differences in the paths that the light follows into the eye. Different paths may correspond to different amounts of parallax difference. In some embodiments, an array of light collimators may be disposed in proximity to the emissive microdisplay. For example, each pixel of an emissive microdisplay may have an associated light collimator that may narrow the angular emission profile of the light emitted by the emissive microdisplay, thereby increasing the amount of emitted light that ultimately reaches the viewer's eye.

[0099] It should be understood that the images formed by the emissive microdisplay may be synchronized in time with the shutters opening in the array of shutters. For example, the opening of one shutter (or multiple adjacent or consecutive shutters) corresponding to one intra-pupillary image may be synchronized or simultaneous with the activation of pixels in the microdisplay. Once another shutter at a desired location for a second intra-pupillary image is opened, the microdisplay may emit light to form that second intra-pupillary image. Additional intra-pupillary images may be formed by synchronizing the opening of shutters at different locations. This time-based sequential presentation of intra-pupillary images to the eye may be referred to as temporal multiplexing or temporally multiplexed display of intra-pupillary images. As a result, in some embodiments, the presentation of intra-pupillary images by the microdisplay may be temporally multiplexed such that different parallax views may be provided by the emissive microdisplay at different times and synchronized with the opening of different shutters providing a desired parallax difference.

[0100] Preferably, the emissive microdisplay is a microLED display, which offers the advantages of high brightness and high pixel density, hi some other embodiments, the microdisplay is a microOLED display.

[0101] In some embodiments, an emissive microdisplay comprises an array of light emitters having a pitch 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, 1-5 μm, 1-4 μm, or 1-2 μm, and an emitter size of 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, with an upper size limit as stated above and a lower limit of 1 μm. Examples of emitter size to pitch ratios include 1:1 to 1:5, 1:2 to 1:4, or 1:2 to 1:3.

[0102] In some embodiments, the display system may utilize an emissive microdisplay in conjunction with an optical collimator array to provide different amounts of parallax difference. The collimator array may be configured to direct light emitted by the microdisplay along different paths that correspond to different amounts of parallax difference. For example, the collimator array may be positioned proximate to or directly on the emissive microdisplay. In some embodiments, the optical collimator is a lenslet. Each collimator of the collimator array may include an associated group of subpixels, each located at a different location relative to the collimator. As a result, light from different subpixels of a group of subpixels will interface differently with the collimator and be directed by the collimator along slightly different paths. These different paths may correspond to different amounts of parallax difference. Thus, each collimator may correspond to a different pixel of the intra-pupillary image, and each subpixel may provide a different light path for that pixel, such that the parallax difference between two or more pixels may be selected by appropriate activation of the subpixels that form those pixels. In some embodiments, different intra-pupillary images may be advantageously formed and provided to the eye simultaneously with the parallax difference determined by the location of the sub-pixels forming the images and a collimator array directing the propagation of light from those sub-pixels.

[0103] As noted above, light from different sub-pixels will follow different paths to the projection optics and thus the viewer's eye. As a result, lateral and / or vertical displacement of the active sub-pixels translates into angular displacement of the light exiting the light collimator array and ultimately propagating through the projection optics towards the viewer's pupil. In some embodiments, an increase in lateral displacement between activated sub-pixels used to form different images may be understood to translate into an increase in angular displacement as measured relative to the microdisplay. In some embodiments, each of the intra-pupillary images used to approximate a particular wavefront may be formed by outputting light from different sub-pixels, thereby providing an angular displacement between the beams of light forming each of the images.

[0104] In some embodiments, the display system may include projection optics, with or without the use of a collimator array or an array of shutters, to direct light into the eye. The emissive microdisplay may be configured to output light encoded with image information to form an intrapupillary image. The light then impinges on and propagates through the projection optics and ultimately to the viewer's eye.

[0105] In some embodiments, the display system may include a combiner eyepiece, which allows the virtual image content to be overlaid with the viewer's view of the world or surroundings. For example, the combiner eyepiece may be an optically transparent waveguide that allows the viewer to see the world. In addition, the waveguide may be utilized to receive, guide, and ultimately output light that forms an intrapupillary image to the viewer's eye. Because the waveguide may be positioned between the viewer and the world, the light output by the waveguide may be perceived to form virtual images that are located on various depth planes within the world. In essence, the combiner eyepiece allows the viewer to receive a combination of light from the display system and light from the world.

[0106] In some embodiments, the display system may also include an eye-tracking system to detect the viewer's gaze direction. Such an eye-tracking system allows appropriate content to be selected and displayed based on where the viewer is looking.

[0107] Preferably, the display system has a small enough exit pupil such that the depth of field provided by the light forming the individual intrapupillary images is substantially infinite and the visual system operates in an "open loop" mode in which the eye cannot accommodate to the individual intrapupillary images. In some embodiments, the light beams forming the individual images occupy an area having a width or diameter of less than about 0.5 mm when incident on the eye. However, it should be understood that the light beams forming a set of intrapupillary images are at least partially non-overlapping, and the set of light beams preferably defines an area greater than 0.5 mm to provide sufficient information to the crystalline lens of the eye to elicit a desired accommodation response based on the wavefront approximation formed by the wavefront of the light forming the intrapupillary images.

[0108] Without being limited by theory, the area defined by the set of beams of light may be considered to mimic a synthetic aperture through which the eye views the scene. It should be understood that viewing the scene through a sufficiently small pinhole in front of the pupil provides a nearly infinite depth of field. Given the small aperture of the pinhole, the eye's lens is not provided with adequate scene sampling to discern distinct depths of focus. As the pinhole expands, additional information is provided to the eye's lens, and natural optical phenomena allow a limited depth of focus to be perceived. Advantageously, the area defined by the set of beams of light and the corresponding set of parallaxically distinct intra-pupillary images may be made larger than a pinhole that would produce an infinite depth of field, and the multiple intra-pupillary images may produce an approximation of the effect provided by the enlarged pinhole described above.

[0109] Some embodiments disclosed herein may provide various advantages. For example, because the microdisplays are emissive, external illumination is not required, thereby facilitating a reduction in the size and weight of the projection system. The small size of these microdisplays allows for the use of a single projector with separate primary color (e.g., red, green, blue) microdisplay panels without requiring an overly large or complex projector. In some embodiments, advantageously, due to the small size and weight of the various microdisplays disclosed herein, different projectors may be used for different primary colors. Additionally, in contrast to typical displays such as LCOS displays, polarized light is not required to provide image information to the light. As a result, light losses associated with polarized light may be avoided. Also, the individual light emitters of the microdisplays have a high etendue, and as a result, the light from each pixel necessarily fills an ultra-large pupil area, which can desirably provide a large eyebox volume. In some embodiments, the emissive microdisplay is a microLED display, which may have a significantly high frame rate (e.g., a frame rate of 1 kHz or greater, including 1-2 kHz). In addition, the emissive microdisplay may have a significantly small pixel pitch (e.g., 1-4 μm, including 2-4 μm or 1-2 μm) and a high pixel density, which may desirably provide high image resolution.

[0110] Reference is now made to the drawings, in which like reference numbers refer to like parts throughout.

[0111] As discussed herein, the perception of an image as "three-dimensional" or "3-D" may be achieved by providing a slightly different presentation of the image to each eye of a viewer. FIG. 2 illustrates a conventional scheme for simulating a three-dimensional image for a user. Two distinct images 190, 200, one for each eye 210, 220, are output to the user. The images 190, 200 are spaced apart from the eyes 210, 220 by a distance 230 along an optical or z-axis parallel to the viewer's line of sight. The images 190, 200 are flat, and the eyes 210, 220 may focus on the images by assuming a single accommodated state. Such a 3-D display scheme relies on the human visual system to combine the images 190, 200 and provide a perception of depth and / or scale of the combined image.

[0112] However, it should be appreciated that the human visual system is more complex and more difficult to provide a realistic perception of depth. For example, many viewers of conventional "3-D" display systems may find such systems uncomfortable or may not perceive any sensation of depth at all. Without being limited by theory, it is believed that a viewer of an object may perceive the object as "three-dimensional" due to a combination of vergence-divergence and accommodation. The vergence-divergence movement of the two eyes relative to one another (i.e., the rotation of the eyes while the pupils converge the gaze of the eyes toward or away from one another to fixate on the object) is closely linked to the focusing (or "accommodation") of the eye lenses and pupils. Under normal conditions, changing the focus of the eye lenses (or accommodating the eyes) from one object to another object at a different distance will automatically produce a matching change in vergence-divergence to the same distance, a relationship known as the "accommodation-vergence-divergence reflex." Similarly, changes in vergence-divergence will induce corresponding changes in accommodation under normal conditions, which accompany changes in lens shape and pupil size. As described herein, many stereoscopic or "3-D" display systems display a scene using a slightly different presentation (and therefore a slightly different image) to each eye, such that a three-dimensional perspective is perceived by the human visual system. However, such systems are uncomfortable for many viewers, especially since they simply provide a different presentation of the scene, i.e., the eyes view all image information, even image information for objects at different depths, in a single accommodated state. However, this works against the "accommodation-vergence-divergence reflex." Display systems that provide a better match between accommodation and vergence-divergence will create a more realistic and comfortable simulation of a three-dimensional image, which will encourage users to wear the display for longer durations.

[0113] FIG. 3 illustrates aspects of an approach for simulating a three-dimensional image using multiple depth planes. Objects at various distances from the eyes 210, 220 on the z-axis are accommodated by the eyes 210, 220 such that the objects are in focus. That is, the eyes 210, 220 assume a particular accommodated state and focus on objects at different distances along the z-axis. As a result, a particular accommodated state may be said to be associated with a particular one of the depth planes 240 having an associated focal length such that an object or part of an object at a particular depth plane is in focus when the eye is in an accommodated state for that depth plane. In some embodiments, a three-dimensional image may be simulated by providing a different presentation of an image for each eye 210, 220, with the presentation of the image also being different for different depth planes. Although shown as separate for clarity of illustration, it should be understood that the fields of view of the eyes 210, 220 may overlap, for example, as the distance along the z-axis increases. Additionally, while shown as flat for ease of illustration, it should be understood that the contour of the depth plane may be curved in physical space such that all features within the depth plane are in focus with the eye in a particular accommodated state.

[0114] The distance between an object and the eye 210 or 220 may also change the amount of divergence of light from that object as viewed by that eye. Figures 4A-4C illustrate the relationship between distance and divergence of light rays. The distance between the object and the eye 210 is represented in the order of decreasing distances R1, R2, and R3. As shown in Figures 4A-4C, the light rays become more divergent as the distance to the object decreases. As the distance increases, the light rays become more collimated. In other words, the light field generated by a point (an object or part of an object) may be said to have a spherical wavefront curvature that is a function of the distance the point is away from the user's eye. The curvature increases with decreasing distance between the object and the eye 210. As a result, at different depth planes, the divergence of the light rays is also different, and the divergence increases with decreasing distance between the depth plane and the viewer's eye 210. Although only a monocular 210 is illustrated in FIGS. 4A-4C and various other figures herein for clarity of illustration, it should be understood that the discussion regarding eye 210 may apply to both eyes 210 and 220 of a viewer.

[0115] Without being limited by theory, it is believed that the human eye is typically capable of interpreting a finite number of depth planes to provide depth perception. As a result, 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. The different presentations may be focused separately by the viewer's eyes, thereby serving to provide depth cues to the user based on the ocular accommodation required to focus on different image features in a scene where the different features are located on different depth planes. This may also cause other image features on other depth planes to appear out of focus, which provides an additional depth sensation for the viewer.

[0116] Since each depth plane has an associated wavefront divergence, some displays may utilize a waveguide having an optical power to output light with a wavefront divergence corresponding to that depth plane to display image content that appears to be at a particular depth plane. Multiple similar but different optical powered waveguides may be utilized to display image content on multiple depth planes. For example, such a system may utilize multiple such waveguides formed in a stack. FIG. 5 illustrates an example of a waveguide stack for outputting image information to a user. The display system 250 includes a stack of waveguides 260 that may be utilized to provide a three-dimensional perception to the eye / brain using multiple waveguides 270, 280, 290, 300, 310 for outputting image information. Image injection devices 360, 370, 380, 390, 400 may be utilized to inject light containing image information into the waveguides 270, 280, 290, 300, 310. In some embodiments, the image input devices 360, 370, 380, 390, 400 may be understood as different light projection systems and / or different pupils of one or more projection systems. The waveguides 270, 280, 290, 300, 310 may be separated from the other waveguides, for example, by air or other low index material, facilitating total internal reflection of light through each of the waveguides. Each waveguide 270, 280, 290, 300, 310 may include structures (e.g., optical gratings and / or lenses 570, 580, 590, 600, 610, respectively) that provide refractive power such that each waveguide outputs light with a pre-set amount of wavefront divergence corresponding to a particular depth plane. Thus, each waveguide 270, 280, 290, 300, 310 places image content on an associated depth plane determined by the amount of wavefront divergence provided by that waveguide.

[0117] However, it should be understood that a one-to-one correspondence between waveguides and depth planes may lead to bulky and heavy devices in systems where multiple depth planes are desired. In such an embodiment, multiple depth planes would require multiple waveguides. In addition, if a color image is desired, an even larger number of waveguides may be required, since each depth plane may have multiple corresponding waveguides, and one waveguide for each primary color (e.g., red, green, or blue) may be required to form a color image.

[0118] Advantageously, various embodiments herein may provide a simpler display system that approximates the desired continuous wavefront by using discrete light beams that form intra-pupillary images that present different parallax views of an object or scene. Furthermore, optical projection systems that utilize emissive microdisplays may reduce the size and weight of the display system relative to projection systems that utilize separate spatial light modulators and light sources. In addition, some embodiments may provide significantly higher frame rates, providing the advantage of flexibility in providing a desired number of intra-pupillary images within a given duration.

[0119] 6A, a pre-accommodation state of an eye 210 and a post-accommodation state in response to receiving a continuous input wavefront 1000 are illustrated. Illustration a) illustrates the pre-accommodation state before the visual system focuses the wavefront 1000 onto the retina 211. Notably, the focal point 212 is not on the retina 211. For example, the focal point 212 may be in front of the retina 211, as illustrated. Illustration b) illustrates the post-accommodation state after the human visual system flexes the pupil musculature of the viewer's eye 210 and focuses the wavefront 1000 onto the retina 211. As illustrated, the focal point 212 may be on the retina 211.

[0120] It has been found that a continuous wavefront, such as the wavefront 1000 of FIG. 6A, can be approximated using multiple wavefronts. FIG. 6B illustrates a pre-accommodation state of the eye 210 and a post-accommodation state in response to receiving a piecewise approximation of the continuous wavefront 1000 of FIG. 6A. Illustration a) of FIG. 6B illustrates the pre-accommodation state of the eye 210, and illustration b) illustrates the post-accommodation state. The approximation may be formed using multiple constituent wavefronts 1010a, 1010b, and 1010c, each associated with a separate beam of light. As used herein, reference numerals 1010a, 1010b, and 1010c may refer to both a beam of light and the associated wavefronts of the beam of light. In some embodiments, the constituent wavefronts 1010a and 1010b may be planar wavefronts, such as those formed by a collimated beam of light. As shown in illustration b), a wavefront approximation 1010 formed by constituent wavefronts 1010a and 1010b is focused by eye 210 onto retina 211, with focal point 212 on retina 211. Advantageously, the pre- and post-accommodation conditions are similar to those produced by the continuous wavefront 1000 shown in FIG.

[0121] It should be understood that the continuous diverging wavefront may be formed using an optical projection system. As mentioned above, US Patent Publication No. 2018 / 0113311, published on April 26, 2018, discloses an exemplary system that uses a light source to illuminate a spatial light modulator 1018. FIG. 7A illustrates an eye accommodating to a diverging wavefront emanating from a finite focal length virtual image provided by a projection system. The system includes a spatial light modulator 1018 and a projection optical system 1020 with a focal length "F" and an external stop. A light source (not shown) provides light to the spatial light modulator 1018, and an image may be formed by the spatial light modulator 1018 by modulating the light. The modulated light containing image information may be directed to the eye 210 through the projection optical system 1020. 7A, the spacing (less than F) between the microdisplay 2000 and the projection optics 1020 may be selected such that a diverging wavefront 1000 is output toward the eye 210. As discussed above with respect to FIG. 6A, the eye 210 may then focus the wavefront 1000 onto the retina 211.

[0122] FIG. 7B illustrates a system for forming an approximation of the diverging wavefront of FIG. 7A utilizing a wavefront segment formed by an infinity-focused virtual image. As described above, the system includes a spatial light modulator 1018 and a projection optical system 1020. As described above, a light source (not shown) provides light to the spatial light modulator 1018, which modulates the light to form an image. The spatial light modulator 1018 can form two images that are shifted relative to each other. The spatial light modulator 1018 is located at a distance F from a back focal plane of the projection optical system 1020, which has a back focal length of F. A light beam 1010a containing image information for a first image propagates through the projection optical system 1020 into the eye 210. A light beam 1010b containing image information for a second image follows a different path through the projection optical system 1020 into the eye 210. The light beams 1010a and 1010b propagate along paths from the spatial light modulator through the projection optics 1020 and into the eye 210 such that the light beams define an angular range for each light beam that matches the angular range of the diverging wavefront 1000 (FIG. 7A). It should be understood that the angular separation between the light beams 1010a and 1010b increases with increasing approximated wavefront divergence.

[0123] Referring now to FIG. 8, an example of parallax views forming the diverging wavefront approximation of FIG. 7B is illustrated. It should be understood that the light beams 1010a, 1010b, and 1010c each form distinctly different images of one view of the same object or scene from slightly different viewpoints corresponding to different locations of the image in space. As illustrated, the images may be launched into the eye 210 sequentially at different times. Alternatively, the images may be launched simultaneously if the optical system allows, or groups of images may be launched simultaneously as discussed herein. In some embodiments, the total duration during which the light forming all of the images is launched into the eye 210 is less than the viewer's flicker fusion threshold. For example, the flicker fusion threshold may be 1 / 60 of a second, and the light beams 1010a, 1010b, and 1010c are all launched into the eye 210 for a duration less than the flicker fusion threshold. The human visual system therefore integrates all of these images, which appear to the eye 210 as if light beams 1010a, 1010b, and 1010c were launched simultaneously into the eye 210. Light beams 1010a, 1010b, and 1010c thus form a wavefront approximation 1010.

[0124] 9, an example of a display system 1001 is illustrated that includes a projection system 1003 for forming the diverging wavefront approximation 1010 of FIGS. 7B and 8. The projection system 1003 includes a microdisplay 2000 that includes a plurality of light emitters 2002 that function as pixels for forming an image. The light emitters 2002 emit light 2002a, 2002b, 2002c that propagates through and is output by the relay / projection optics 1020. The light then continues through an open shutter 20061 of an array of shutters 2004. The open shutter 20061 may be understood to form a shutter aperture sub-pupil. Additionally, light propagating through the open shutter 20061 may be understood as light beam 1010a, which propagates into the eye 210 and forms an intrapupillary image (see, for example, the image formed by the beam of light 1010a in FIG. 8). Preferably, the array of shutters 2004 is located at or close to the plane of the pupil of the eye 210.

[0125] It should be understood that the numerical aperture of the light received by the projection optics 1020 is determined by the focal length and the diameter of the projection optics. The light emerging from the projection optics 1020 forms a pupil, which in some embodiments may be at the exit aperture of the projection optics 1020. In addition, the light 2002a, 2002b, 2002c propagating through and exiting the projection optics 1020 continue to propagate in different directions, but also overlap to define a volume 2003. The volume 2003 is an eyebox, which in some embodiments may be pyramidal in shape. As mentioned above, the eyebox includes contributions from all of the light emitters 2002 of the microdisplay 2000. Preferably, the size (e.g., lateral dimension) of the projection optics pupil and the size (e.g., lateral dimension) of the eyebox in which the eye 210 is placed are as large or larger in size (e.g., lateral dimension) than the pupil of the eye 210 when viewing an image from the microdisplay 2000. As a result, preferably the entire image formed on the microdisplay 2000 can be viewed by the eye 210. Additionally, as described herein, the array of shutters 2004 is preferably located at or near the pupil plane of the eye 210 such that the array of shutters 2004 is also within the eyebox volume 2003.

[0126] 9, as described herein, the microdisplay 2000 may comprise an array of light emitters 2002. Examples of light emitters include organic light emitting diodes (OLEDs) and micro light emitting diodes (microLEDs). It should be understood that OLEDs utilize organic materials to emit light and microLEDs utilize inorganic materials to emit light.

[0127] Advantageously, some micro LEDs provide higher brightness and higher efficiency (in terms of lux / W) than OLEDs. In some embodiments, the micro display is preferably a micro LED display. The micro LED may utilize inorganic materials for light emission, for example, III-V materials such as GaAs, GaN, and / or GaIn. An example of a GaN material includes InGaN, which may be used in some embodiments to form a blue or green light emitter. An example of a GaIn material includes AlGaInP, which may be used in some embodiments to form a red light emitter. In some embodiments, the light emitter 2002 may emit an initial color of light, which may be converted to other desired colors using phosphor materials or quantum dots. For example, the light emitter 20002 may emit blue light, which excites phosphor materials or quantum dots that convert the blue wavelength light to green or red wavelengths.

[0128] In some embodiments, the display system 1001 may include an eye tracking device 1022, e.g., a camera, configured to monitor the gaze of the eyes. Such monitoring may be used to determine the direction in which the viewer is looking, which may be used to select appropriate image content with respect to that direction. The eye tracking device 1022 may track both of the viewer's eyes, or each eye may include its own associated eye tracking device. In some embodiments, the vergence and divergence movement of the viewer's eyes may be tracked and the convergence point of the eyes' gaze may be determined to determine the direction and distance at which the eyes are pointed.

[0129] Continuing with reference to FIG. 9, the display system 1001 may also include a control system 1024 for determining the timing and type of image content provided by the display system. In some embodiments, the control system 1024 comprises one or more hardware processors with memory storing programs for controlling the display system 1001. For example, the system 1024 may be configured to control the opening of individual shutters of the shutter array 2004, the activation of the emitters 2002 of the microdisplay 2000, and / or the interpretation and reaction of the display system 1001 to data received from the eye tracking device 1022. Preferably, the system 1024 includes a calculation module 1024a configured to receive input regarding a desired depth plane or wavefront divergence and calculate the appropriate shutters to open in order to form a parallax view with an appropriate amount of difference for the desired depth plane or wavefront divergence. Additionally, the calculation module 1024a may be configured to determine the appropriate activation of the light emitters 2002 of the microdisplay 2000 to form an image of the desired parallax view. The system 1024 may also include a synchronization module 1024b configured to synchronize activation of certain shutters of the shutter array 2004 with emission of light by the light emitter 2002 of the microdisplay 2000 to form an image that provides a desired parallax view. In addition, the system 1024 may include an eye tracking module 1024c that receives input from the eye tracking device 1022. For example, the eye tracking device 1022 may be a camera configured to image the eye 210. Based on the image captured by the eye tracking device 1022, the eye tracking module 1024c may be configured to determine the orientation of the pupil and extrapolate the line of sight of the eye 210. This information may be electronically communicated to the calculation module 1024a. The calculation module 1024a may be configured to select image content based on the line of sight or line of sight of the eye 210 (preferably also based on the line of sight or line of sight of the viewer's other eye, e.g., based on the fixation point of the viewer's eye).

[0130] 10A, an example of an array 2004 of shutters 2006 is illustrated. The illustrated view is a front view, as seen from the direction of light from the microdisplay 2000 impinging on the array 2004. As shown, the array 2004 may extend in two dimensions and may comprise rows and columns of shutters 2006. Preferably, each of the shutters 2006 may be individually activated or opened. The location of an open shutter 2006 may correspond to a desired location of the intra-pupil image. For example, the shutter array 2004 shown in FIG. 9 may have an open shutter 2006a that corresponds to the location of the light beam 1010a shown in FIG. 8.

[0131] It should be understood that the array 2004 may have other overall configurations. For example, for horizontal parallax only driven accommodation, the array 2004 may be a horizontal line of shutters 2006, as shown in Figure 10A. In some other embodiments, for vertical parallax only driven accommodation, the array 2004 may be a vertical line of shutters 2006, as shown in Figure 10B.

[0132] Although shown as a square grid, the shutters 2006 may be arrayed in any configuration, which provides some parallax difference when different ones of the shutters 2006 are opened. For example, the shutters 2006 may be arranged in a hexagonal grid. In addition, the shutters 2006 may have shapes other than square. For example, the shutters 2006 may have a hexagonal shape, a circular shape, a triangular shape, etc. In some embodiments, multiple shutters may be opened, which may allow the size and / or shape of the opening to be selected as desired.

[0133] It should be understood that the shutters discussed herein are structures that can be made independently transparent to light. As a result, an open shutter is one that is controlled to be transparent to light, and a closed shutter is one that is controlled to block light or be opaque. In some embodiments, the shutters may be physical structures that move between a first position and a second position to transmit or block light by moving out of or into the path of light, respectively. In some other embodiments, the shutters may include chemical species that reversibly change state or orientation to change the light transmission properties of the shutter. Examples of structures suitable for use as shutters include pixels forming a transmissive pixelated liquid crystal display, MEMS-based micromechanical structures (e.g., that can move vertically and / or horizontally in and out of the path of light), or other arrays of segmented structures capable of high switching rates between at least two states. Additional examples of shutters include ferroelectric shutters. Preferably, the shutters are capable of changing state (switching between transmissive (open) and non-transmissive (closed) states) by a factor determined by the number of shutter aperture sub-pupils (or intra-pupillary images) desired for the display system at a rate that exceeds the frame update rate of the microdisplay 2000. For example, if the microdisplay 2000 produces images at 120 Hz and three sub-pupils are desired, the shutters 2006 of the shutter array 2004 are preferably capable of a switching rate of at least three times the microdisplay frame rate or 3 x 120 Hz (e.g., 360 Hz or higher).

[0134] Preferably, the projection system 1003 (FIG. 9) produces a relatively long depth of field, which may be controlled by limiting the aperture in the system. Without being limited by theory, as discussed herein, the projection system may be configured to provide images to the eye with an effective pupil diameter small enough to force the human visual system to operate in an "open loop" mode, since the eye is unable to individually accommodate to such images. However, it is believed that multiple intrapupillary images provide sufficient information to the eye to elicit a desired accommodative response. As discussed herein, the wavefront of light forming the intrapupillary images collectively provides an approximation of the wavefront to which the eye accommodates. In some embodiments, the projection system 1003 may be configured to provide images with an effective pupil diameter of about 0.5 mm or less (e.g., 0.2-0.5 mm), which is believed to be small enough to force the human visual system to operate in an "open loop" mode. As a result, in some embodiments, the shutter 2006, when open, provides an opening having a width of 0.5 mm or less (eg, 0.2-0.5 mm).

[0135] 9, it will be understood that the illustrated open shutter 20061 is opened at a first time (t=t1) to provide an initial intra-pupillary image and show a first parallax view. Subsequently, at a later time (t=t2), another shutter may be opened to provide a second intra-pupillary image and show a second parallax view.

[0136] 11, an example of the projection system of FIG. 9 is illustrated that provides a different, parallaxically distinct intra-pupillary image at a later time (e.g., time t=t2). As shown, shutter 20062 is opened to provide a beam of light 1010b into eye 210. Light beam 1010b may form the intra-pupillary image shown on the right side of FIG. 8. It should be understood that additional shutters may be opened at other times to provide other intra-pupillary images, with a set of intra-pupillary images to approximate the wavefront curvature preferably being provided to the eye within the flicker fusion threshold.

[0137] Referring again to FIG. 9, as described herein, the flicker fusion threshold of the human visual system imposes a time constraint on the number of images that can be thrown into the eye 210 while still being perceived as being thrown simultaneously. For example, the processing bandwidth of the control system 1024 and the ability to switch the light emitting areas of the light source 1026 and the light modulators of the microdisplay 2000 may limit the number of images that can be thrown into the eye 210 within the duration allowed by the flicker fusion threshold. Given this finite number of images, the control system 1024 may be configured to make a selection regarding the image to be displayed. For example, within the flicker fusion threshold, the display system may be required to throw a set of parallaxically distinct intrapupillary images into the eye, and each parallax view may in turn require images of different primary colors to form a full color image. In some embodiments, the formation of a full color image using primary color images is branched off from the elucidation of the desired accommodation response. For example, without being limited by theory, it may be considered possible to induce a desired accommodation response with monochromatic light. In such cases, the parallaxically distinct intrapupillary images used to elicit an accommodation response would be in only one color. As a result, it would not be necessary to form the parallaxically distinct intrapupillary images using light of other colors, thereby freeing up time within the flicker fusion threshold for other types of images to be displayed. For example, a set of larger parallaxically distinct intrapupillary images may be generated to better approximate the wavefront.

[0138] In some other embodiments, the control system 1024 may be configured to spend less time within the flicker fusion threshold to display images of colors of light to which the human visual system is less sensitive. For example, the human visual system is less sensitive to blue light than to green light. As a result, the display system may be configured to generate a greater number of images formed using green light than images formed using blue light.

[0139] It should be understood that the light emitters of the microdisplay 2000 may emit light with a large angular emission profile (e.g., a Lambertian angular emission profile). Undesirably, such an angular emission profile may "waste" light because only a small portion of the emitted light may ultimately propagate through the projection optics 1020 and reach the viewer's eye.

[0140] Referring now to FIG. 12, in some embodiments, a light collimator may be utilized to narrow the angular emission profile of light emitted by the light emitter. FIG. 12 illustrates an example of the projection system of FIGS. 9 and 11 with an array of light collimators 2010 between the emissive microdisplay 2000 and the projection optics 1020. The array of light collimators 2010 is disposed in front of the light emitters 2002. In some embodiments, each light emitter 2002 has a dedicated light collimator 2010, i.e., each light emitter 2002 is matched 1 / 1 with its associated light collimator 2010 (one light collimator 2010 per light emitter 2002). The light collimators may be configured to pick up light from the associated light emitter 2002 and image the light to optical infinity (or in some other embodiments, some other non-infinite plane).

[0141] The light collimators 2010 may be configured to narrow the angular emission profile of the incoming light. For example, as shown, each light collimator 2010 receives light from an associated light emitter 2002 with a relatively wide initial angular emission profile and outputs that light with an angular emission profile narrower than the wide initial angular emission profile of the light emitter 2002. In some embodiments, the rays of light exiting the light collimator 2010 are more parallel than the rays of light received by the light collimator 2010 prior to being transmitted through and exiting the collimator 2010. Advantageously, the light collimator 2010 may increase the efficiency of the use of light to form an image by allowing more of that light to be directed into the viewer's eye than would be the case if the collimator 2010 were not present.

[0142] Preferably, the light collimators 2010 are positioned in close proximity to the light emitters 2002 to capture a large percentage of the light output by the light emitters 2002. In some embodiments, a gap may exist between the light collimators 2010 and the light emitters 2002. In some other embodiments, the light collimators 2010 may contact the light emitters 2002. Preferably, the entire or majority of the cone of light from the light emitters 2002 is incident on a single associated light collimator 2010. Thus, in some embodiments, each light emitter 2002 is smaller (occupies a smaller area) than the light receiving surface of the associated light collimator 2010. In some embodiments, each light emitter 2002 has a width that is smaller than the spacing between neighboring light emitters 2002.

[0143] The light collimator 2010 may take a variety of forms. For example, in some embodiments, the light collimator 2010 may be a microlens or lenslet, including spherical or lenticular lenslets. As discussed herein, each microlens preferably has a width greater than the width of the associated light emitter 2002. The microlenses may be formed from curved transparent materials such as glass or polymers, including resins such as photoresists and epoxies. In some embodiments, the light collimator 2010 may be a nanolens, for example, a diffractive optical grating. In some embodiments, the light collimator 2010 may be a metasurface and / or a liquid crystal grating. In some embodiments, the light collimator 2010 may take the form of a reflective well.

[0144] 13, another example of a projection system 1003 for forming the diverging wavefront approximation of FIGS. 7B and 8 is illustrated. In some embodiments, the projection system 1003 may comprise a microdisplay 2000 and an array of optical collimators 2010 disposed between the microdisplay 2000 and the projection optics 1020. The projection system is part of a display system 1001 having a control system 1024 for controlling the projection system 1003 and the eye tracking device 1022, as described above with respect to FIG.

[0145] Continuing with reference to FIG. 13, the microdisplay 2000 may comprise a plurality of light emitters 2002. The light emitters 2002 may be arranged in groups, with two or more light emitters per group. Each group of light emitters 2002 includes an associated light collimator 2010. As shown, each group of light collimators 2002g may include two light emitters 20021, 20022, with the associated light collimator 20101 configured to capture light from both light emitters. Preferably, the associated light collimator 20101 has a width that extends across both light emitters 20021, 20022 such that the associated light collimator 20101 encompasses an area that exceeds the area of ​​both light emitters 20021, 20022. In some embodiments, the light collimator 2010 is spaced apart from the light emitters 20021, 20022. In some other embodiments, the light collimator 2010 may be in contact with the light emitters 20021, 20022. For example, the light collimator 2002 may be a lenslet, and the light emitters 20021, 20022 may be disposed within the associated lenslet 20101.

[0146] It should be understood that the location of the light emitters relative to the associated light collimator can affect the direction of light propagating out of the light collimator. The light emitters 20021, 20022 interface differently (e.g., are located at different locations) with the associated light collimator 20101, which causes the light collimator 20101 to direct light from each of the light emitters 20021, 20022 along different paths to the projection optical system 1020 and then to the eye 210. Preferably, the locations of the light emitters 20021, 20022 and the physical parameters (e.g., size and shape) of the associated light collimator 20101 are configured to provide different light paths corresponding to different intra-pupillary images. Two light emitters 20021, 20022 are provided for clarity of illustration, but it should be understood that each group of light emitters associated with a light collimator may have more than two light emitters. For example, groups 2002g may each have three or more light emitters, four or more light emitters, etc. A greater number of spatially distinct light emitters facilitates a greater number of potential levels of parallax difference.

[0147] In some embodiments, image light from a light emitter in each group of light emitters may be directed by an associated light collimator 2010 and projection optics 1020 to form a first intra-pupillary image as a beam of light 1010a, and image light from another light emitter in each group of light emitters may be directed by an associated light collimator 2010 and projection optics 1020 to form a second intra-pupillary image as a beam of light 1010b. As discussed herein, the light beams 1010a, 1010b preferably have a sufficiently small diameter that the eye is unable to accommodate the individual images formed by each beam of light. In some embodiments, the diameter of each beam of light 1010a, 1010b at the pupil of the eye 210 is about 0.5 mm or less (e.g., 0.2-0.5 mm).

[0148] Continuing with reference to FIG. 13, the projection system 1003, including the group 2002g of light emitters 20021, 20022, may use spatial multiplexing to form different intra-pupillary images. With respect to such spatial multiplexing, light emitters at different locations may be used to form different intra-pupillary images, i.e., different light emitters of each group of light emitters may provide image information for different intra-pupillary images. Light from a corresponding light emitter of each group of light emitters is directed by an optical structure (e.g., a light collimator of the array of light collimators 2010 and the projection optics 1020) to form one of the light beams 1010a, 1010b to form a corresponding intra-pupillary image. Advantageously, the intra-pupillary images may be provided to the eye simultaneously, obviating the need to rapidly sequentially provide images below the flicker fusion threshold. This may reduce requirements on the frame rate of the microdisplay 2000 and the supporting control system 1024.

[0149] Referring now to FIG. 14, it will be appreciated that the projection system 1003 of FIG. 13 may include both light collimators with associated groups of light emitters and also an array of shutters 2004 to provide a combination of spatial and temporal multiplexing. The array of shutters 2004 may further refine the location and / or size of the beam of light that enters the eye and forms the intrapupillary image. For example, the beam of light output by the array of light collimators 2010 may be larger than desired for forming the intrapupillary image (e.g., larger than desired for open-loop operation of the eye, including larger than 0.5 mm diameter). The shutters of the shutter array 2004 may be utilized to limit the size of the light beam that ultimately enters the eye 210. Additionally, each beam of light provided by the light collimators of the collimator array 2010 may impinge on multiple shutters. As a result, the shutters can provide an additional level of parallax difference for each incoming beam of light, which can facilitate the presentation of virtual content on a larger number of depth planes than would be provided by just the beams of light output by the optical collimator array 2010.

[0150] In some embodiments, a display system may be temporally multiplexed in one dimension (e.g., along the x-axis) and spatially multiplexed in another dimension (e.g., along an orthogonal dimension such as the y-axis). For example, the light collimator may be a lenticular lenslet rather than a spherical lenslet, and may be configured to provide different beams of light from spatially distinct light emitters to different locations along a first axis, orthogonal to a second axis, which may be the elongation axis of the lenticular lenslet. An array of shutters may be utilized to form sub-pupils at different points and different times along that second axis. For example, sub-pupil positioning along a first axis may be achieved by spatial multiplexing by activating different light emitters in each group of light emitters associated with a lenticular lenslet (elongated along a second axis), while sub-pupil positioning along the second axis may be provided by temporal multiplexing by opening shutters on the second axis at desired times (e.g., times that overlap with the activation of corresponding light emitters used for spatial multiplexing).

[0151] 15, an example of a range of depth planes provided by the projection system disclosed herein is illustrated. The range extends from a far plane at optical infinity to a near plane closer to the eye 210. The far plane at optical infinity may be provided by an intra-pupillary image formed by light beams (e.g., light beams 1010a and 1010b) that are substantially collimated or parallel with respect to each other. With respect to such a far plane, the light beams may be understood to have no parallax difference or to have low parallax difference.

[0152] 15, closer depth planes may be provided using higher levels of disparity difference. In some embodiments, the perceived proximity of the near plane to the eye 210 may be determined by the maximum disparity difference between the light beams forming the intrapupillary image. For example, the maximum disparity difference between light beams 1010a and 1010b may be determined by the maximum distance between the shutters of the array of shutters 2004 (FIGS. 9-12 and 14) and / or the maximum difference in direction provided by each light collimator 1010a for light from light emitter 2002 of its associated group of light emitters (FIGS. 13 and 14).

[0153] 16A, an example of a display system is illustrated that includes a projection system that includes an array of shutters and a pupil relay combiner eyepiece for superimposing image content onto a user's view of the world. Preferably, the eyepiece 1030 is optically transparent, allowing light 2012 from the world to propagate through the eyepiece and into the viewer's eye 210 so that the viewer can see the world. In some embodiments, the eyepiece 1030 includes one or more waveguides 1032 having an in-coupling optical element, such as an in-coupling optical element 770 and an out-coupling optical element 800. The in-coupling optical element 770 receives image light 2014 from the projection system 1003 and redirects the image light by total internal reflection to propagate through the eyepiece 1030 to the out-coupling optical element 800. The out-coupling optical element 800 outputs the image light 2014 to the viewer's eye 210. Advantageously, the eyepiece 1030 preserves all of the attributes of the image provided by the projection system 1003, so that the fast switching parallax view is accurately depicted through the eyepiece 1030. It should be appreciated that the image light 2014 may correspond to light emitted by the microdisplay 2000 and provided, for example, through the lights 2002a, 2002b, 2002c (FIG. 9) or the array of light collimators 2010 (FIGS. 13 and 14).

[0154] As shown, the projection system 1003 may include an array of shutters 2004 on a pupil plane 2005 through which light exits the projection system 1003 towards an incoupling optic 770. A lens structure 2016 may be provided between the shutter array 2004 and the incoupling optic 770 to relay the image light 2014. In some embodiments, the lens structure 2016 may also collimate the image light 2014 for propagation within a waveguide 1032 forming the eyepiece 1030.

[0155] The internal coupling optical element 770 and the external coupling optical element 800 may be refractive or reflective structures. Preferably, the internal coupling optical element 770 and the external coupling optical element 800 are diffractive optical elements. Examples of diffractive optical elements include surface relief features, volumetric topological features, metamaterials, or liquid crystal polarization gratings. Although shown disposed on the same side of the waveguide 1032, it should be understood that the internal coupling optical element 770 and the external coupling optical element 800 may be disposed on different sides of the waveguide 1032. Also, although shown on the side of the waveguide 1032 facing the projection optics 1020, one or both of the internal coupling optical element 770 and the external coupling optical element 800 may be disposed on the same side of the waveguide 1032 as the projection optics 1020.

[0156] FIG. 16B illustrates an example of a display system comprising a projection system comprising an array of light collimators to provide different intra-pupillary images and a pupil relay combiner eyepiece to superimpose image content onto a user's view of the world. The display system of FIG. 16B is similar to that of FIG. 16A, except that the projection system 1003 is similar to that of FIG. 13, rather than the projection system of FIG. 9. As shown, the projection system 1003 may comprise a microdisplay 2000 and an array of light collimators 2010 between the microdisplay 2000 and the projection optics 1020. The microdisplay 2000 may comprise a plurality of light emitters formed in groups 2002g, with one group per light collimator 2010. The location of a light emitter relative to its associated light collimator determines the direction of light propagating out of the light collimator and thus the parallax difference between images formed using different light emitters 20021, 20022 of the group 2002g of light emitters. As a result, activation of different light emitters in a group of light emitters sets a parallax difference between intra-pupillary images formed using the different light emitters, in some embodiments, light from a first light emitter 20021 of each group of light emitters 2002g may be directed by an associated light collimator 2010 and projection optics 1020 to form a first intra-pupillary image with a beam of light 1010a, and light from a second light emitter 20022 of each group of light emitters 2002g may be directed by an associated light collimator 2010 and projection optics 1020 to form a second intra-pupillary image with a beam of light 1010b.

[0157] It should be understood that any of the embodiments of the projection system disclosed herein may be utilized in the display system of Figures 16A and 16B, for example, as projection system 1003 in those figures. For example, projection system 1003 may utilize both an array of light collimators and shutters, for example, as shown in Figures 12 and 14.

[0158] FIG. 17A illustrates another embodiment of a projection system comprising an array of shutters and a pupil relay combiner eyepiece for superimposing image content onto a user's view of the world. The illustrated display system is similar to that of FIG. 16A, except for the optical structure associated with the eyepiece 1030. The eyepiece 1030 may comprise a partially transparent relay mirror 2020 to reflect image light 2014 into the eye 210. As shown, the image light 2014 is in-coupled by an in-coupling optical element 770, which redirects the light 2014 to propagate through a waveguide 1032. The eyepiece 1030 includes an out-coupling optical element 800, which directs the image light 2014 forward through a quarter wave plate 2018 on the front surface of the waveguide 1032. As shown, a partially transparent relay mirror 2020 may be in front of and spaced apart from the quarter wave plate 2018 and the waveguide 1032 .

[0159] FIG. 17B illustrates another embodiment of a display system comprising a projection system comprising an array of light collimators to provide different intra-pupillary images and a pupil relay combiner eyepiece to superimpose the image content onto the user's view of the world. The illustrated display system is similar to that of FIG. 16B, except for the optical structure associated with the eyepiece 1030. The eyepiece 1030 and associated structure are similar to that illustrated in FIG. 17A. As discussed above, the image light 2014 is in-coupled by the in-coupling optical element 770 and propagates through the waveguide 1032 by total internal reflection. The out-coupling optical element 800 outputs the image light 2014 forward, away from the eye 210, through a quarter wave plate 2018, and to a partially transparent relay mirror 2020. As shown, a partially transparent relay mirror 2020 may be in front of and spaced from the quarter wave plate 2018 and the waveguide 1032 to reflect the image light 2014 into the eye 210. In some embodiments, the partially transparent relay mirror 2020 may be configured to selectively reflect light of the polarization transmitted through the quarter wave plate 2018.

[0160] 18, an example of a display system 1001 having a projection system 1003 comprising an eye tracking system 1022 and a combiner eyepiece 1030 with a pupil expander 1034 is illustrated. The pupil expander 1034 may comprise, for example, a diffractive optical element configured to replicate the projection system pupil across the eyepiece 1030. Because the pupil expander 1034 replicates the projection system pupil across a large area that may be traversed by a viewer's pupil through eye movement, the image formed by the microdisplay 2000 and the location of the light emitting region of the light source 1026 can be updated in real time based on input from the eye tracking system 1022. Advantageously, this configuration allows for a larger eyebox for more comfortable viewing and reduces limitations on the relative positioning of the eye and combiner and variations in interpupillary distance.

[0161] 19, an example of a display system 1001 is illustrated having a projection system 1003 with an eye tracking system 1022 and a combiner eyepiece 1030 with a pupil expander 1035 configured to produce a non-infinity depth plane. In some embodiments, the non-infinity depth plane may be at 3 meters, which results in a budgeted accommodation of about 2.5 meters to infinity. For example, given the tolerance of the human visual system for accommodation-vergence-divergence mismatch, virtual content at a distance of about 2.5 meters from the viewer to infinity may be placed on the 3 meter depth plane with little discomfort. In such a system, parallaxically distinct intrapupillary images may be used to drive accommodation for a narrower range of depth planes, possibly all closer to the viewer than a fixed "default" focal plane. In some embodiments, the system may also incorporate an eye tracking system 1022 to determine the distance of the viewer's fixation, for example, based on the convergence-divergence angle of the viewer's eyes.

[0162] It should be understood that the microdisplay 2000 may be a monochrome display and the display system 1001 may be configured to provide a monochrome image to the eye 210. More preferably, the display system 1001 is configured to provide a full-color image to the eye 210. In such an embodiment, the microdisplay 2000 may be a full-color microdisplay. For example, a full-color image may be formed by providing different images formed by different primary colors (e.g., three or more primary colors, such as red, green, and blue), which in combination are perceived by a viewer to be a full-color image. The microdisplay 2000 may be configured to emit light of all primary colors. For example, the different colors may be emitted by different light emitters.

[0163] In some other embodiments, a full-color image may be formed using primary color images provided by multiple microdisplays, at least some of which are monochrome microdisplays. For example, different monochrome microdisplays may be configured to provide different primary color images. The primary color images may be provided to the eye 210 simultaneously or may be multiplexed in time (e.g., different primary color images to form a single full-color image may all be provided to the eye 210 within the flicker fusion threshold).

[0164] 20A-20B illustrate an example of a projection system having multiple emissive microdisplays 2000a, 2000b, 2000c. Each of the microdisplays 2000a, 2000b, 2000c may be similar to the microdisplays 2000 disclosed herein (see, e.g., FIGS. 9, 11-14, and 16A-17B). Light from the microdisplays 2000a, 2000b, 2000c is combined by an optical combiner 1050 and directed toward the projection optics 1020 and ultimately to the viewer's eye 210. As discussed herein, in some embodiments, light from the projection optics 1020 may be directed to an eyepiece 1030, which may be a waveguide assembly comprising one or more waveguides.

[0165] In some embodiments, the microdisplays 2000a, 2000b, 2000c may be monochrome microdisplays, each of which may output light of a different primary color to provide a different monochrome image, which may be combined by a viewer to form a full color image.

[0166] 20A, the optical combiner 1050 receives image light 2001a, 2001b, 2001c from each of the microdisplays 2000a, 2000b, 2000c, respectively, and combines the light such that the light generally propagates in the same direction, e.g., toward the projection optics 1020. In some embodiments, the optical combiner 1050 may be a dichroic X-cube prism having reflective internal surfaces 1052, 1054 that redirect the image light 2001c, 2001a, respectively, to the projection optics 1020. The projection optics 1020 converges or focuses the image light, which impinges on an array of shutters 2004. The image light 2001a, 2001b, 2001c then propagates through an open shutter (e.g., shutter 20061) into the eye 210.

[0167] 20B, an example of an optical projection system 1010 is illustrated with a plurality of emissive microdisplays 2000a, 2000b, 2000c and associated arrays of optical collimators 2010a, 2010b, 2010c, respectively. Each of the arrays 2010a, 2010b, 2010c may be similar to the array 2010 disclosed herein (see, e.g., FIGS. 12-14, 16B, and 17B).

[0168] In some embodiments, the arrays 2010a, 2010b, 2010c may each comprise a light collimator configured to narrow the angular emission profile of the image light 2001a, 2001b, 2001c emitted by the microdisplays 1030a, 1030b, 1030c. The image light 2001a, 2001b, 2001c subsequently propagates through the optical combiner 1050 to the projection optics 1020 and then into the eye 210. In addition, each light collimator may have an associated group of light emitters (e.g., as illustrated in FIGS. 13, 14, 16B, and 17B) as discussed herein, and may direct light from different light emitters of each group of emitters along different paths corresponding to different amounts of parallax difference to form different intra-pupillary images.

[0169] 20A and 20B, in some other embodiments, the microdisplays 2000a, 2000b, 2000c may each be a full-color display configured to output light of all primary colors. For example, the microdisplays 2000a, 2000b, 2000c may each include a light emitter configured to emit red, green, and blue light. The microdisplays 2000a, 2000b, 2000c may be identical and may display the same image. However, utilizing multiple microdisplays may provide 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 utilized with an optical combiner 1050 configured to combine the light from all of these microdisplays.

[0170] 20A and 20B, in some embodiments, the monochrome microdisplay 2000b directly facing the output surface 1051 may advantageously output green light. It should be understood that the reflective surfaces 1052, 1054 may have optical losses when reflecting light from the microdisplays 2000c, 2000a, respectively. In addition, of the primary colors red, green, and blue, the human eye is most sensitive to the color green. As a result, the monochrome microdisplay 2000b facing the output surface of the optical combiner 1050 preferably outputs green light so that the green light can travel directly through the optical combiner 1050 without having to be reflected to be output from the optical combiner 1050. However, it will be understood that the green monochrome microdisplay may face the other surface of the optical combiner 1050 in some other embodiments.

[0171] In some embodiments, as discussed herein, the display system may include an eyepiece (e.g., eyepiece 1030, FIGS. 16A-19) to relay light output by the projection optics 1020 to the eye 210. In some embodiments, the eyepiece may include a single waveguide configured to in-couple and out-couple light of all primary colors.

[0172] In some other embodiments, the eyepiece 1030 may comprise multiple waveguides forming a stack of waveguides. Each waveguide has a separate in-coupling optical element for in-coupling the image light. For example, each waveguide may have an associated in-coupling optical element configured to in-couple light of different primary colors or different wavelength ranges. In some embodiments, the number of waveguides is proportional to the number of primary colors provided by the microdisplays 2000a, 2000b, 2000c. For example, if there are three primary colors, the number of waveguides in the eyepiece 1030 may include a set of three waveguides or multiple sets of three waveguides. Examples of arrays of waveguides and associated structures are discussed in U.S. Provisional Application No. 62 / 800363, filed February 1, 2019, the entire disclosure of which is incorporated herein by reference.

[0173] 21, an example of eyepiece 660 (which may correspond to eyepiece 1030 of FIGS. 16A-19) is illustrated that includes a stacked waveguide assembly for outputting different wavelengths of light corresponding to different primary colors. In some embodiments, the waveguide assembly includes waveguides 670, 680, and 690, which may individually correspond to waveguide 1032 (FIGS. 16A-17B). Each waveguide includes an associated internal coupling optical element, e.g., internal coupling optical element 700 is disposed on a major surface (e.g., upper major surface) of waveguide 670, internal coupling optical element 710 is disposed on a major surface (e.g., upper major surface) of waveguide 680, and internal coupling optical element 720 is disposed on a major surface (e.g., upper major surface) of waveguide 690. In some embodiments, one or more of the incoupling optical elements 700, 710, 720 may be disposed on a bottom major surface of the respective waveguide 670, 680, 690 (particularly, one or more of the incoupling optical elements are reflective polarizing optical elements). As shown, the incoupling optical elements 700, 710, 720 may be disposed on an upper major surface of that respective waveguide 670, 680, 690 (or on top of the next lower waveguide), and particularly, the incoupling optical elements are transmissive polarizing optical elements. In some embodiments, the incoupling optical elements 700, 710, 720 may be disposed within the body of the respective waveguide 670, 680, 690. In some embodiments, as discussed herein, the incoupling optical elements 700, 710, 720 are wavelength selective such that they selectively redirect one or more wavelengths of light while transmitting other wavelengths of light. Although illustrated on one side or corner of the respective waveguides 670, 680, 690, it should be understood that the internal coupling optical elements 700, 710, 720 may be disposed within other areas of the respective waveguides 670, 680, 690 in some embodiments.

[0174] As shown, the in-coupling optical elements 700, 710, 720 may be laterally offset from one another. In some embodiments, each in-coupling optical element may be offset to receive light without that light passing through another in-coupling optical element. For example, each in-coupling optical element 700, 710, 720 may be configured to receive light from a different image input device 360, 370, 380, 390, and 400, as shown in FIG. 6, and may be separated (e.g., laterally spaced) from the other in-coupling optical elements 700, 710, 720 so as to not receive substantially any light from others of the in-coupling optical elements 700, 710, 720. In some embodiments, the in-coupling optical elements 700, 710, 720 are vertically aligned and not laterally offset.

[0175] Each waveguide may also include an associated optically dispersive element, for example, optically dispersive element 730 is disposed on a major surface (e.g., a top major surface) of waveguide 670, optically dispersive element 740 is disposed on a major surface (e.g., a top major surface) of waveguide 680, and optically dispersive element 750 is disposed on a major surface (e.g., a top major surface) of waveguide 690. In some other embodiments, optically dispersive elements 730, 740, 750 may be disposed on the bottom major surfaces of associated waveguides 670, 680, 690, respectively. In some other embodiments, optically dispersive elements 730, 740, 750 may be disposed on both the top and bottom major surfaces of associated waveguides 670, 680, 690, respectively, or optically dispersive elements 730, 740, 750 may be disposed on different ones of the top and bottom major surfaces in different associated waveguides 670, 680, 690, respectively.

[0176] The waveguides 670, 680, 690 may be spaced apart and separated, for example, by gas, liquid, and / or solid layers of material. For example, as shown, layer 760a may separate the waveguides 670 and 680, and layer 760b may separate the waveguides 680 and 690. In some embodiments, layers 760a and 760b are formed from a low index material (i.e., a material having a lower index of refraction than the material forming the immediate neighbors of the waveguides 670, 680, 690). Preferably, the index of refraction of the material forming layers 760a, 760b is 0.05 or more or 0.10 or less than the index of refraction of the material forming the waveguides 670, 680, 690. Advantageously, the lower refractive index layers 760a, 760b may act as cladding layers to promote TIR of light through the waveguides 670, 680, 690 (e.g., TIR between the top and bottom major surfaces of each waveguide). In some embodiments, the layers 760a, 760b are formed from air. Although not shown, it should be understood that the top and bottom of the illustrated set of waveguides 660 may include immediate cladding layers.

[0177] With continued reference to FIG. 21, light rays 770, 780, 790 are incident on and launched into waveguides 670, 680, 690 by projection system 1003 (FIGS. 9, 11-14, and 16A-17B).

[0178] In some embodiments, the light beams 770, 780, 790 have different properties, e.g., different wavelengths or different wavelength ranges, that may correspond to different colors. The internal coupling optical elements 700, 710, 720 each deflect the incident light such that the light propagates through a respective one of the waveguides 670, 680, 690 by TIR.

[0179] For example, incoupling optical element 700 may be configured to deflect light beam 770 having a first wavelength or range of wavelengths. Similarly, transmitted light beam 780 impinges on and is deflected by incoupling optical element 710, which is configured to selectively deflect light of a second wavelength or range of wavelengths. Similarly, light beam 790 is deflected by incoupling optical element 720, which is configured to selectively deflect light of a third wavelength or range of wavelengths.

[0180] 21 , the incoupling light rays 770, 780, 790 are deflected by the incoupling optical elements 700, 710, 720, respectively, and then propagate by TIR in the waveguides 670, 680, 690, respectively. The light rays 770, 780, 790 then impinge on the optically dispersive elements 730, 740, 750, respectively. The optically dispersive elements 730, 740, 750 deflect the light rays 770, 780, 790 to propagate towards the outcoupling optical elements 800, 810, 820, respectively.

[0181] In some embodiments, the optically dispersive elements 730, 740, 750 are orthogonal pupil expanders (OPEs). In some embodiments, the OPEs deflect or disperse the light to the out-coupling optical elements 800, 810, 820 and may increase the beam or spot size of this light as it propagates to the out-coupling optical elements. In some embodiments, for example, if the beam size is already the desired size, the optically dispersive elements 730, 740, 750 may be omitted and the in-coupling optical elements 700, 710, 720 may be configured to deflect the light directly to the out-coupling optical elements 800, 810, 820. In some embodiments, the out-coupling optical elements 800, 810, 820 are exit pupils (EPs) or exit pupil expanders (EPEs) that direct the light to the viewer's eye 210 (see FIG. 18 ). It should be understood that the OPE may be configured to increase a dimension of the eyebox in at least one axis, and the EPE may increase the eyebox in an axis that intersects, e.g., is perpendicular to, the axis of the OPE.

[0182] Thus, in some embodiments, the eyepiece 660 includes a waveguide 670, 680, 690, an in-coupling optical element 700, 710, 720, a light dispersive element (e.g., OPE) 730, 740, 750, and an out-coupling optical element (e.g., EP) 800, 810, 820 for each primary color. The waveguides 670, 680, 690 may be stacked with an air gap / cladding layer between each one. The in-coupling optical element 700, 710, 720 redirects or deflects the incoming light into its waveguide (with different in-coupling optical elements receiving different wavelengths of light). The light then propagates at an angle that will result in TIR within the individual waveguides 670, 680, 690. In the illustrated embodiment, light ray 770 (e.g., blue light) is deflected by the first in-coupling optical element 700 in the manner described above, then continues to bounce back down the waveguide, interacting with the optically dispersive element (e.g., OPE) 730 and then the out-coupling optical element (e.g., EP) 800. Light rays 780 and 790 (e.g., green and red light, respectively) pass through the waveguide 670, where light ray 780 impinges on and is deflected by the in-coupling optical element 710. Light ray 780 will then proceed via TIR back down the waveguide 680, to its optically dispersive element (e.g., OPE) 740 and then the out-coupling optical element (e.g., EP) 810. Finally, light ray 790 (e.g., red light) passes through the waveguide 690 and impinges on the optically in-coupling optical element 720 of the waveguide 690. The light in-coupling optical element 720 deflects the light beam 790 such that it propagates by TIR to a light dispersive element (e.g., OPE) 750 and then by TIR to an out-coupling optical element (e.g., EP) 820. The out-coupling optical element 820 then finally out-couples the light beam 790 to a viewer, who also receives the out-coupled light from the other waveguides 670, 680.

[0183] As noted above, the incoupling optical elements 700, 710, 720 may be laterally offset from one another. In such an embodiment, the image light 2001a, 2001b, 2001c from different ones of the microdisplays 2000a, 2000b, 2000c may follow different paths to the eyepiece 1030 such that they impinge on different ones of the incoupling optical elements 700, 710, 720. When the image light 2001a, 2001b, 2001c includes light of different primary colors, the associated incoupling optical elements 700, 710, 720 may each be configured to selectively incoupling light of different wavelengths, as discussed herein.

[0184] Different optical paths for the image light 2001a, 2001b, 2001c may be provided by the combiner 1050 (FIGS. 20A-20B), by one or more of the arrays 2010a, 2010b, 2010c, and / or by angling one or more of the microdisplays 2000a, 2000b, 2000c at appropriate angles relative to the reflective surfaces 1052, 1054 of the optical combiner 1050. For example, with reference to FIGS. 20A-20B, the optical combiner 1050 may be configured to redirect the image light 2001a, 2001b, 2001c emitted by the microdisplays 2000a, 2000b, 2000c such that the image light propagates along different optical paths to impinge on associated ones of the internal combining optical elements 700, 710, 720. Thus, the optical combiner 1050 combines the image light 2001a, 2001b, 2001c in the sense that the light may exit the optical combiner in slightly different directions, but the image light is output from a common face of the optical combiner 1050. For example, the reflective internal surfaces 1052, 1054 of the X-cube prism may each be angled to direct the image light 2001a, 2001b, 2001c along different paths to the eyepiece 1030. As a result, the image light 2001a, 2001b, 2001c may be incident on different associated ones of the internal combining optical elements 700, 710, 720. In some embodiments, the microdisplays 2000a, 2000b, 2000c may be appropriately angled with respect to the reflective internal surfaces 1052, 1054 of the X-cube prism to provide the desired light path to the incombining optical elements 700, 710, 720. For example, a face of one or more of the microdisplays 2000a, 2000b, 2000c may be angled to match a face of the optical combiner 1050 such that image light emitted by the microdisplays is incident on the reflective internal surfaces 1052, 1054 at the appropriate angle and propagates towards the associated incombining optical elements 700, 710, 720. It should be appreciated that in addition to a cube, the optical combiner 1050 may take the form of a variety of other polyhedrons.For example, the optical combiner 1050 may be in the shape of a right angle prism having at least two faces that are not square.

[0185] As discussed herein, the perception of a full-color image by a user may be achieved in some embodiments using time division multiplexing. For example, different ones of the micro LED arrays 2000a, 2000b, 2000c may be activated at different times to generate different primary color images. In such embodiments, the different primary color images forming a single full-color image may be displayed sequentially quickly enough that the human visual system does not perceive the primary color images as being displayed at different times, i.e., the different primary color images forming a single full-color image may all be displayed within a duration that is short enough that the user perceives the primary color images as being presented simultaneously, rather than being separated in time. For example, the primary color images may be displayed sequentially at a frame rate that is higher than the flicker fusion threshold of the human visual system. As an example, the flicker fusion threshold may be 60 Hz, which is considered to be fast enough that most users do not perceive the primary color images as being displayed at different times. In some embodiments, the different primary color images are displayed sequentially at a rate higher than 60 Hz. It should be appreciated that time division multiplexing may advantageously reduce the computational load on a processor (e.g., a graphics processor) utilized 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 2000a, 2000b, 2000c.

[0186] 22, there is illustrated an example of a wearable display system 60. Display system 60 may correspond to display system 1001 of FIGS. 9 and 13, with a projection system 1003 for each eye of a viewer or user 90.

[0187] The display system 60 includes a display 70 and various mechanical and electronic modules and systems to support the functionality of the display 70. The display 70 may be coupled to a frame 80, which is wearable by a display system user or viewer 90 and configured to position the display 70 in front of the user's 90 eye. The display 70 may be considered eyewear in some embodiments. In some embodiments, a speaker 100 is coupled to the frame 80 and configured to be positioned adjacent to the ear canal of the user 90 (in some embodiments, another speaker, not shown, is positioned adjacent to the user's other ear canal to provide stereo / adjustable sound control). In some embodiments, the display system may also include one or more microphones 110 or other devices to detect sound. In some embodiments, the microphones may be configured to allow the user to provide input or commands (e.g., voice menu command selections, natural language questions, etc.) to the system 60 and / or enable audio communication with other persons (e.g., other users of similar display systems). The microphone may further be configured as an ambient sensor and 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 outwardly directed 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 121 may include one or more cameras, which may be positioned, for example, facing outward, to capture images similar to at least a portion of the user 90's normal field of view. In some embodiments, the display system may also include an ambient sensor 120a, which may be separate from the frame 80 and attached to the body of the user 90 (e.g., on the user 90's head, torso, limbs, etc.). The ambient sensor 120a may, in some embodiments, be configured to obtain data characterizing a physiological state of the user 90. For example, the sensor 120a may be an electrode.

[0188] 22, the display 70 is operably coupled by a communication link 130, such as wired or wireless connectivity, to a local data processing module 140, which may be mounted in a variety of configurations, such as fixedly attached to the frame 80, fixedly attached to a helmet or hat worn by the user, built into headphones, or otherwise removably attached to the user 90 (e.g., in a backpack configuration, in a belt-coupled configuration). Similarly, the sensor 120a may be operably coupled to the local processor and data module 140 by a communication link 120b, such as wired or wireless connectivity. The local processing and data module 140 may comprise a hardware processor and digital memory, such as non-volatile memory (e.g., flash memory or hard disk drive), both of which may be utilized to aid in processing, caching, and storing data. The data may include a) data captured from sensors (e.g., which may be operatively coupled to the frame 80 or otherwise attached to the user 90), such as image capture devices (such as cameras), microphones, inertial measurement units, accelerometers, compasses, GPS units, wireless devices, gyroscopes, and / or other sensors disclosed herein, and / or b) data obtained and / or processed using the remote processing module 150 and / or remote data repository 160 (including data related to virtual content), possibly for passing to the display 70 after processing or retrieval. The local processing and data module 140 may be operatively coupled to the remote processing module 150 and the remote data repository 160 by communication links 170, 180, such as via wired or wireless communication links, such that these remote modules 150, 160 are operatively coupled to each other and available as resources to the local processing and data module 140.In some embodiments, local processing and data module 140 may include one or more of an image capture 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 to frame 80 or may be a stand-alone structure that communicates with local processing and data module 140 by a wired or wireless communication path. In some embodiments, local processing and data module 140 may include one or more graphics processors and may correspond to control system 1024 (FIGS. 9 and 13).

[0189] 22, in some embodiments, the remote processing module 150 may comprise one or more processors configured to analyze and process the data and / or image information. In some embodiments, the remote data repository 160 may comprise a digital data storage facility, 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 include one or more remote servers, which provide information, e.g., information for generating augmented reality 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, allowing for fully autonomous use from the remote modules.

[0190] It should be understood that each of the processes, methods, and algorithms described herein and / or depicted in the figures may be embodied in code modules, and thus fully or partially automated, executed by one or more physical computing systems, hardware computer processors, application-specific circuits, and / or electronic hardware configured to execute specific and particular computer instructions. For example, the computing systems may include general-purpose computers (e.g., servers) or special-purpose computers, special-purpose circuits, etc., programmed with specific computer instructions. The code modules may be compiled and linked into an executable program, installed in a dynamic link library, or written in an interpreted programming language. In some implementations, certain operations and methods may be performed by circuitry specific to a given function.

[0191] Furthermore, certain implementations of the functionality of the present disclosure may be sufficiently mathematically, computationally, or technically complex that special purpose hardware (utilizing appropriate specialized executable instructions) or one or more physical computing devices may be required to implement the functionality, e.g., due to the amount or complexity of the calculations involved, or to provide results in substantially real-time. For example, a video may contain many frames, each frame may have millions of pixels, and specifically programmed computer hardware may be required to process the video data to provide the desired image processing task or application in a commercially reasonable amount of time.

[0192] The code modules or any type of data may be stored on any type of non-transitory computer readable medium, such as physical computer storage devices, including hard drives, solid state memory, random access memory (RAM), read only memory (ROM), optical disks, volatile or non-volatile storage devices, combinations of the same, and / or the like. In some embodiments, the non-transitory computer readable medium may be part of one or more of the local processing and data module (140), the remote processing module (150), and the remote data repository (160). The methods and modules (or data) may also be transmitted as a data signal generated (e.g., as part of a carrier wave or other analog or digital propagating signal) over a variety of computer readable transmission media, including wireless-based and wired / cable-based media, and may take a variety of forms (e.g., as part of a single or multiplexed analog signal, or as multiple discrete digital packets or frames). The results of the disclosed processes or process steps may be stored persistently or otherwise in any type of non-transitory tangible computer storage device, or communicated via a computer readable transmission medium.

[0193] Any process, block, state, step, or functionality in the flow diagrams described herein and / or depicted in the accompanying figures should be understood as potentially representing a code module, segment, or portion of code that includes one or more executable instructions for implementing a specific function (e.g., logical or arithmetic) or step in the process. Various processes, blocks, states, steps, or functionality may be combined, rearranged, added to, removed from, modified, or otherwise altered from the illustrative examples provided herein. In some embodiments, additional or different computing systems or code modules may perform some or all of the functionality described herein. The methods and processes described herein are also not limited to any particular sequence, and the blocks, steps, or states associated therewith can be performed in other sequences as appropriate, e.g., serially, in parallel, or in some other manner. Tasks or events may be added to or removed from the disclosed exemplary embodiments. Furthermore, the separation of various system components in the embodiments described herein is for illustrative purposes and should not be understood as requiring such separation in all embodiments. It should be understood that the program components, methods, and systems described may generally be integrated together in a single computer product or packaged into multiple computer products.

[0194] In the foregoing specification, the invention has been described with reference to specific embodiments thereof. It will, however, be apparent that various modifications and changes can be made therein without departing from the broader spirit and scope of the invention. The specification and drawings are, therefore, to be regarded in an illustrative rather than a restrictive sense.

[0195] Indeed, it should be understood that the systems and methods of the present disclosure each have several innovative aspects, none of which is solely responsible for or required for the desirable attributes disclosed herein. The various features and processes described above may be used independently of one another or may be combined in various ways. All possible combinations and subcombinations are intended to fall within the scope of the present disclosure.

[0196] Certain features described herein in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable subcombination. Furthermore, although features may be described above as acting in a combination and may even be initially claimed as such, one or more features from the claimed combination may in some cases be deleted from the combination, and the claimed combination may be directed to a subcombination or variation of the subcombination. No single feature or group of features is required or essential to every embodiment.

[0197] In particular, it should be understood that conditional statements used herein, such as "can," "could," "might," "may," "eg," and the like, are generally intended to convey that certain embodiments include certain features, elements, and / or steps while other embodiments do not, unless specifically stated otherwise or understood otherwise within the context as used. Thus, such conditional statements are generally not intended to agree that features, elements, and / or steps are in any way required for one or more embodiments, or that one or more embodiments necessarily include logic for determining whether those features, elements, and / or steps should be included or performed in any particular embodiment, with or without authorial input or prompting. The terms "comprising," "including," "having," and the like, are synonymous and used inclusively in a non-limiting manner and do not exclude additional elements, features, acts, operations, etc. Also, the term "or" is used in its inclusive sense (and not its exclusive sense), thus, for example, when used to connect a list of elements, the term "or" means one, some, or all of the elements in the list. In addition, the articles "a," "an," and "the," as used in this application and the appended claims, should be interpreted to mean "one or more" or "at least one," unless otherwise specified. Similarly, although operations may be depicted in the figures in a particular order, this should be recognized that such operations need not be performed in the particular order depicted, or in sequential order, or that all of the depicted operations need not be performed to achieve desirable results. Additionally, the figures may diagrammatically depict one or more exemplary processes in the form of a flow chart. However, other operations not depicted may also be incorporated within the diagrammatically depicted exemplary methods and processes. For example, one or more additional operations may be performed before, after, simultaneously with, or during any of the depicted operations.In addition, operations may be rearranged or reordered in other embodiments. In some situations, multitasking and parallel processing may be advantageous. Furthermore, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the program components and systems described may generally be integrated together in a single software product or packaged into multiple software products. Additionally, other implementations are within the scope of the following claims. In some cases, the actions recited in the claims may be performed in a different order and still achieve desirable results.

[0198] Thus, the claims are not intended to be limited to the embodiments shown herein but are to be accorded the widest scope consistent with the disclosure, the principles and novel features disclosed herein.

Claims

1. A head mounted display system, comprising: a microdisplay comprising an array of groups of light emitters; an array of optical collimators on top of the light emitters, each optical collimator being associated with one of the groups of light emitters and extending across all the light emitters of the associated group of light emitters; a projection optical system, wherein the array of light collimators is between the light emitter and the projection optical system, and the display system is configured to display a virtual object on a depth plane by projecting a set of parallax-distinct intra-pupillary images of the object into the same eye of a viewer; and one or more processors; and a memory for storing instructions. Equipped with The instructions, when executed by the one or more processors, cause the display system to: determining each light emitter of the group of light emitters for activation based on a level of parallax difference associated with an image formed by the light emitter; forming a first parallaxically distinct intrapupillary image by activating a first light emitter of the group of light emitters; forming a second parallaxically distinct intrapupillary image by activating a second light emitter of said group of light emitters; Performing an operation including the first and second parallaxically distinct intrapupillary images providing different views of the virtual object to a same eye of the viewer; a head mounted display system, wherein activating the first light emitter of the group of light emitters overlaps in time with activating the second light emitter of the group of light emitters to project the first and second parallaxically distinct intrapupillary images into the same eye of the viewer within a flicker fusion threshold of 1 / 60 seconds.

2. A display system as described in claim 1, wherein the first and second parallaxically different intrapupillary images are presented simultaneously into the same eye of the viewer.

3. The display system of claim 1, wherein the optical collimator is a lenslet.

4. The display system of claim 1, further comprising an array of selectively activated shutters for selectively transmitting the image light to the eye from different locations, the array of selectively activated shutters being positioned within an eyebox volume of the projection optical system.

5. The optical collimator is a lenticular lenslet configured to provide different beams of light from optical emitters of an associated group of optical emitters to different locations along a first axis; 10. The display system of claim 1, wherein the array of shutters is arranged to form a sub-pupil along a second axis orthogonal to the first axis.

6. The display system of claim 1, further comprising a pupil relay combiner eyepiece configured to relay the image light to the eye of the viewer, the array of selectively activated shutters configured to adjust propagation of the image light to the pupil relay combiner eyepiece, the pupil relay combiner eyepiece comprising a plurality of waveguides, each waveguide comprising an internal coupling optical element and an external coupling optical element.

7. A display system as described in claim 4, wherein the shutter comprises a chemical species having reversibly changeable states, the states providing different amounts of light transmission.

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