Time-multiplexed display of virtual content at various depths

Abstract

Techniques for operating an optical system are disclosed. The world light may be linearly polarized along the first axis. When the optical system operates according to the first state, polarization of the world light may be rotated 90 degrees, the world light may be linearly polarized along a second axis perpendicular to the first axis, and a zero net power may be applied to the world light. When the optical system is operating according to the second state, the virtual image light may be projected onto an eyepiece of the optical system, the world light and the virtual image light may be linearly polarized along the second axis, the polarization of the virtual image light may be rotated 90 degrees, and a non-zero net power may be applied to the virtual image light.

Description

[0001] This application is a divisional application of an application with a filing date of January 10, 2020, a PCT international application number of PCT / US2020 / 013130, a Chinese national phase application number of 202080019801.6, and an invention name of “Time-multiplexed display of virtual content at various depths”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims the benefit of priority to U.S. Provisional Patent Serial No. 62 / 791,441, filed on January 11, 2019, entitled “TIME-MULTIPLEXED DISPLAY OF VIRTUAL CONTENT AT VARIOUSDEPTHS,” the contents of which are incorporated herein in their entirety. Background Art

[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 to be real or can be perceived as real. A virtual reality or "VR" scene typically involves the presentation of digital or virtual image information without transparency to other actual real-world visual input; an augmented reality or "AR" scene typically involves the presentation of digital or virtual image information as an enhancement of the visualization of the actual world around the user.

[0005] Despite the advances made in these display technologies, there is a need in the art for improved methods, systems, and apparatus related to augmented reality systems, and particularly display systems. Summary of the invention

[0006] The present disclosure generally relates to technologies for improving the performance and user experience of optical systems. More particularly, embodiments of the present disclosure provide systems and methods for operating augmented reality (AR) devices, including adaptive lens assemblies and / or shutter elements for displaying virtual content at various depths. Although the present invention is described with reference to AR devices, the present disclosure is applicable to various applications in computer vision and image display systems. An overview of the present disclosure is provided below with reference to a series of examples.

[0007] Example 1 is a method of operating an optical system, the method comprising: receiving light associated with a world object at the optical system; linearly polarizing the light associated with the world object along a first axis through a world-side polarizer of the optical system; when the optical system is operating according to a first state: rotating the polarization of the light associated with the world object by 90 degrees through a world-side switchable wave plate of the optical system; linearly polarizing the light associated with the world object along a second axis perpendicular to the first axis through a user-side polarizer of the optical system; applying zero net refractive power to the light associated with the world object through a lens assembly of the optical system; when the optical system is operating according to a second state: projecting light associated with a virtual image through a projector of the optical system onto an eyepiece of the optical system; coupling out the light associated with the virtual image toward the user-side polarizer through the eyepiece; and polarizing the light associated with the world object through the user-side polarizer. The invention relates to a method for linearly polarizing light associated with a virtual image and light associated with a virtual image along a second axis; rotating the polarization of the light associated with the virtual image by 90 degrees through a user-side switchable wave plate; and applying a non-zero net refractive power to the light associated with the virtual image through a lens assembly; wherein, when the world-side switchable wave plate is electrically activated and the user-side switchable wave plate is not electrically activated, the optical system operates according to a first state; wherein, when the user-side switchable wave plate is electrically activated and the world-side switchable wave plate is not electrically activated, the optical system operates according to a second state; wherein a world-side polarizer is coupled to the world-side switchable wave plate; wherein the world-side switchable wave plate is coupled to the eyepiece on the world side of the eyepiece; wherein the user-side polarizer wave plate is coupled to the eyepiece on the user side of the eyepiece; wherein the lens assembly is coupled to the user-side polarizer; wherein the user-side switchable wave plate is positioned between two layers of the lens assembly.

[0008] Example 2 is an optical system comprising: a world-side polarizer configured to linearly polarize light associated with a world object along a first axis; a world-side switchable wave plate coupled to the world-side polarizer and configured to rotate the polarization of the light associated with the world object by 90 degrees when the optical system is operating according to a first state; an eyepiece coupled to the world-side switchable wave plate; a projector configured to project light associated with a virtual image onto the eyepiece when the optical system is operating according to a second state; and a user-side polarizer coupled to the eyepiece and configured to: when the optical system is operating according to the first state, rotate the polarization of the light associated with the world object along a direction perpendicular to the first axis. a second axis linearly polarized along the second axis; and, when the optical system is operating according to the second state, causing light associated with world objects and light associated with virtual images to be linearly polarized along the second axis; a lens assembly coupled to the user-side polarizer and configured to: apply zero net refractive power to light associated with world objects when the optical system is operating according to the first state; and apply non-zero net refractive power to light associated with virtual images when the optical system is operating according to the second state; and a user-side switchable wave plate positioned between two layers of the lens assembly and configured to rotate the polarization of light associated with the virtual image by 90 degrees when the optical system is operating according to the second state.

[0009] Example 3 is a method of operating an optical system, the method comprising: receiving light associated with a world object at the optical system; linearly polarizing the light associated with the world object along a first axis through one or more world-side shutter elements of the optical system; when the optical system is operating according to a first state: rotating the polarization of the light associated with the world object by 90 degrees through one or more world-side shutter elements; linearly polarizing the light associated with the world object along a second axis perpendicular to the first axis through one or more user-side shutter elements of the optical system; when the optical system is operating according to a second state: projecting light associated with a virtual image onto an eyepiece of the optical system through a projector of the optical system; linearly polarizing the light associated with the world object and the light associated with the virtual image along the second axis through one or more user-side shutter elements; and rotating the polarization of the light associated with the virtual image by 90 degrees through one or more user-side shutter elements.

[0010] Example 4 is a method according to one or more of Examples 3, further comprising: applying zero net refractive power to light associated with objects in the world through a lens component of the optical system when the optical system is operating according to the first state.

[0011] Example 5 is a method according to one or more Examples 3, further comprising: applying a non-zero net refractive power to light associated with the virtual image through a lens component of the optical system when the optical system is operating according to the second state.

[0012] Example 6 is a method according to one or more Examples 3, further comprising: when the optical system is operating according to the second state, coupling light associated with the virtual image toward one or more user-side shutter elements through the eyepiece.

[0013] Example 7 is a method according to one or more of Examples 3, wherein the one or more world-side shutter elements include: a world-side polarizer; and a world-side switchable wave plate.

[0014] Example 8 is a method according to one or more of Examples 7, wherein the one or more user-side shutter elements include: a user-side polarizer; and a user-side switchable wave plate.

[0015] Example 9 is a method according to one or more of Examples 8, wherein the optical system includes a lens assembly.

[0016] Example 10 is a method according to one or more of Examples 9, wherein the optical system operates according to a first state when the world-side switchable wave plate is electrically activated and the user-side switchable wave plate is not electrically activated.

[0017] Example 11 is a method according to one or more of Examples 9, wherein the optical system operates according to the second state when the user-side switchable wave plate is electrically activated and the world-side switchable wave plate is not electrically activated.

[0018] Example 12 is a method according to one or more of Examples 9, wherein the world-side polarizer is coupled to the world-side switchable wave plate.

[0019] Example 13 is a method according to one or more of Examples 9, wherein a world-side switchable wave plate is coupled to the eyepiece on the world side of the eyepiece.

[0020] Example 14 is a method according to one or more of Examples 9, wherein a user-side polarizer wave plate is coupled to the eyepiece on a user side of the eyepiece.

[0021] Example 15 is a method according to one or more of Examples 9, wherein the lens assembly is coupled to a user-side polarizer.

[0022] Example 16 is a method according to one or more of Examples 9, wherein the user-side switchable wave plate is positioned between two layers of the lens assembly.

[0023] Example 17 is an optical system comprising: one or more world-side shutter elements configured to: linearly polarize light associated with a world object along a first axis; and rotate the polarization of the light associated with the world object by 90 degrees when the optical system operates according to a first state; an eyepiece coupled to the one or more world-side shutter elements; a projector configured to project light associated with a virtual image onto the eyepiece when the optical system operates according to a second state; and one or more user-side shutter elements coupled to the eyepiece and configured to: linearly polarize light associated with the world object along a second axis perpendicular to the first axis when the optical system operates according to the first state; linearly polarize light associated with the world object and light associated with the virtual image along the second axis when the optical system operates according to the second state; and rotate the polarization of light associated with the virtual image by 90 degrees when the optical system operates according to the second state.

[0024] Example 18 is an optical system according to one or more of Examples 17, further comprising: a lens assembly coupled to one or more user-side shutter elements.

[0025] Example 19 is an optical system according to one or more of Examples 18, wherein the lens assembly is configured to apply zero net refractive power to light associated with objects in the world when the optical system is operating according to the first state.

[0026] Example 20 is an optical system according to one or more of Examples 18, wherein the lens assembly is configured to apply a non-zero net refractive power to light associated with the virtual image when the optical system is operating according to the second state.

[0027] Example 21 is an optical system according to one or more of Examples 17, wherein the eyepiece is configured to couple light associated with the virtual image toward one or more user-side shutter elements when the optical system is operating according to the second state.

[0028] Example 22 is an optical system according to one or more of Examples 17, wherein the one or more world-side shutter elements include: a world-side polarizer; and a world-side switchable wave plate.

[0029] Example 23 is an optical system according to one or more of Examples 22, wherein the one or more user-side shutter elements include: a user-side polarizer; and a user-side switchable wave plate.

[0030] Example 24 is an optical system according to one or more of Examples 23, wherein the optical system operates according to a first state when the world-side switchable wave plate is electrically activated and the user-side switchable wave plate is not electrically activated.

[0031] Example 25 is an optical system according to one or more of Examples 23, wherein the optical system operates according to a second state when the user-side switchable wave plate is electrically activated and the world-side switchable wave plate is not electrically activated.

[0032] Example 26 is an optical system according to one or more of Examples 23, wherein the world-side polarizer is coupled to the world-side switchable wave plate.

[0033] Example 27 is an optical system according to one or more of Examples 23, wherein a world-side switchable wave plate is coupled to the eyepiece on the world side of the eyepiece.

[0034] Example 28 is an optical system according to one or more of Examples 23, wherein a user-side polarizer wave plate is coupled to the eyepiece on a user side of the eyepiece.

[0035] Example 29 is an optical system according to one or more of Examples 23, wherein the lens assembly is coupled to a user-side polarizer.

[0036] Example 30 is an optical system according to one or more of Examples 23, wherein a user-side switchable wave plate is positioned between two layers of the lens assembly.

[0037] Example 31 is a display device, comprising: a waveguide component, which is configured to guide light in a lateral direction parallel to an output surface of the waveguide component, and the waveguide component is also configured to couple the guided light through the output surface; and an adaptive lens, which is disposed on a first side of the waveguide component, the adaptive lens component being configured to receive the coupled-out light from the waveguide component and selectively switch between multiple states with different refractive powers, wherein the adaptive lens component includes a lens stack, which is configured to apply polarization-dependent refractive power to linearly polarized light, the lens stack including a birefringent lens and an isotropic lens in contact with each other, wherein contact surfaces of the birefringent lens and the isotropic lens form a conformal interface.

[0038] Example 32 is a display device according to one or more Examples 31, further comprising: a second adaptive lens assembly disposed on a second side of the waveguide assembly opposite to the first side, the second adaptive lens assembly being configured to selectively switch between a plurality of states having different refractive powers, and comprising: a second lens stack configured to apply polarization-dependent refractive power to linearly polarized light, wherein the second lens stack comprises a second birefringent lens and a second isotropic lens in contact with each other to form a conformal interface therebetween.

[0039] Example 33 is a display device according to one or more of Examples 32, wherein each of the first adaptive lens assembly and the second adaptive lens assembly further includes a switchable half-wave plate, the switchable half-wave plate comprising a twisted nematic (TN) liquid crystal (LC) optically coupled to a corresponding one of the lens stack or the second lens stack, wherein the switchable half-wave plate is configured to maintain the polarization of linearly polarized light passing through it when deactivated and to change the polarization of linearly polarized light passing through it when activated.

[0040] Example 34 is a display device according to one or more Examples 33, further comprising: on a second side opposite to the first side of the waveguide assembly: a shutter configured to temporally alternately block and pass light incident thereon; and a linear polarizer.

[0041] Example 35 is a display device according to one or more of Examples 34, wherein the waveguide component includes a cholesteric liquid crystal and is configured to couple out circularly polarized light.

[0042] Example 36 is a display device according to one or more of Examples 35, wherein the waveguide assembly is inserted by a pair of quarter wave plates.

[0043] Example 37 is an optical system comprising: a projector configured to emit light; at least one waveguide optically coupled to the projector and configured to receive light from the projector and redirect the light toward a user; a shutter assembly comprising at least one component positioned adjacent to the at least one waveguide, wherein the shutter assembly is controllable to allow a variable amount of ambient light from the user's environment to pass through it toward the user; an adaptive lens assembly positioned between the at least one waveguide and the user, wherein the adaptive lens assembly is controllable to impart a variable amount of refractive power to light passing through it toward the user; and a control circuit communicatively coupled to the projector, the shutter assembly, and the adaptive lens assembly, wherein the control circuit The control circuit is configured to synchronously switch the shutter assembly and the adaptive lens assembly between two or more states, the two or more states comprising: a first state in which the shutter assembly is configured to allow a first amount of ambient light from the user's environment to pass through it toward the user, and the adaptive lens assembly is configured to impart a first refractive power to the light passing through it; and a second state in which the shutter assembly is configured to allow a second amount of ambient light from the user's environment to pass through it toward the user, and the adaptive lens assembly is configured to impart a second refractive power to the light passing through it, wherein the second amount of ambient light is less than the first amount of ambient light, and the second refractive power is greater than the first refractive power.

[0044] Example 38 is an optical system according to one or more of Examples 37, wherein the first amount of ambient light includes a maximum amount of ambient light from the user's environment that the shutter assembly is configured to allow to pass through it toward the user, and the first refractive power includes a minimum refractive power that the adaptive lens assembly is configured to impart to light passing through it.

[0045] Example 39 is an optical system according to any one or more of Examples 37 or 38, wherein, in a second state, the control circuit is configured to cause the projector to emit light representing virtual content that will be perceived by the user as being located at a first depth in front of the user.

[0046] Example 40 is an optical system according to one or more of Examples 39, wherein the control circuit is configured to determine a second amount of ambient light and a second amount of refractive power based on a first depth in front of the user at which virtual content will be perceived by the user.

[0047] Example 41 is an optical system according to one or more of Examples 39, wherein, in a first state, the control circuit is configured to cause the projector to emit light representing virtual content that will be perceived by the user as being located at a second depth in front of the user, the second depth being greater than the first depth.

[0048] Example 42 is an optical system according to one or more of Examples 41, wherein the second depth is substantially equal to optical infinity.

[0049] Example 43 is an optical system according to one or more of Examples 39, wherein, in the first state, the control circuit is configured to cause the projector to not emit light.

[0050] Example 44 is an optical system according to any one or more of Examples 37 or 38, wherein the control circuit is configured to cause the shutter assembly and the adaptive lens assembly to synchronously switch between two or more states at a rate greater than or equal to a minimum switching frequency.

[0051] Example 45 is an optical system according to one or more of Examples 44, wherein the minimum switching frequency is 120 Hz.

[0052] Example 46 is an optical system according to one or more of Examples 44, further comprising: an ambient light sensor configured to measure the intensity of ambient light from the user's environment; wherein the control circuit is communicatively coupled to the ambient light sensor and is further configured to determine a rate at which the shutter assembly and the adaptive lens assembly are synchronously switched between two or more states based on data received from the ambient light sensor.

[0053] Example 47 is an optical system according to one or more of Examples 38, wherein the adaptive lens assembly is configured to impart a minimum refractive power of approximately zero to light passing through it.

[0054] Example 48 is an optical system as described in any of the above examples, wherein the second ambient light amount includes a shutter assembly configured to allow a minimum amount of ambient light from the user's environment to pass through it toward the user, and the second refractive power includes the adaptive lens assembly configured to impart a maximum refractive power to light passing through it.

[0055] Example 49 is an optical system comprising: a projector configured to emit light; at least one waveguide optically coupled to the projector and configured to receive light from the projector and redirect the light toward a user; a shutter assembly comprising at least one component positioned adjacent to at least one waveguide, wherein the shutter assembly is controllable to allow a variable amount of ambient light from the user's environment to pass through it toward the user; an adaptive lens assembly positioned between at least one waveguide and the user, wherein the adaptive lens assembly is controllable to impart a variable amount of refractive power to light passing through it toward the user; and a control circuit communicatively coupled to the projector, the shutter assembly, and the adaptive lens assembly, wherein the control circuit is configured to synchronously: cause the adaptive lens assembly to change the amount of refractive power imparted to light passing through it toward the user; and cause the shutter assembly to change the amount of ambient light from the user's environment that is allowed to pass through it toward the user inversely to the amount of refractive power imparted by the adaptive lens assembly to light passing through it.

[0056] Example 50 is an optical system as described in any of the above examples, wherein at least one waveguide is further configured to allow ambient light from the user's environment to pass through it toward the user.

[0057] Example 51 is an optical system as described in any of the above examples, wherein at least one component of the shutter assembly includes at least one component located between at least one waveguide and the user's environment.

[0058] Example 52 is an optical system as described in any of the above examples, wherein at least one component of the shutter assembly includes at least one component located between at least one waveguide and the user.

[0059] Example 53 is an optical system as described in any of the above examples, wherein at least one component of the shutter assembly includes at least one component located between at least one waveguide and the adaptive lens assembly.

[0060] Example 54 is an optical system as described in any of the above examples, wherein at least one waveguide includes a plurality of waveguides.

[0061] Example 55 is a non-transitory computer-readable medium storing instructions that, when executed by one or more processors, cause the one or more processors to at least partially perform the method of any of the above examples.

[0062] Example 56 is an optical system comprising: a projector configured to emit light; at least one waveguide optically coupled to the projector and configured to receive light from the projector and redirect the light toward a user; a shutter assembly comprising at least one component positioned adjacent to the at least one waveguide, wherein the shutter assembly is selectively switchable between different states, in which the shutter assembly is configured to allow different amounts of ambient light from the user's environment to pass through it toward the user, respectively; an adaptive lens assembly positioned between the at least one waveguide and the user, wherein the adaptive lens assembly is selectively switchable between different states, in which the adaptive lens is configured to impart different amounts of wavefront divergence to light passing through it toward the user, respectively; and a control circuit communicatively coupled to the projector, the shutter assembly, and the adaptive lens assembly.

[0063] Example 57 is an optical system according to Example 56, wherein the control circuit is configured to cause the shutter assembly and the adaptive lens assembly to synchronously switch between two or more states at a specific rate, the two or more states including: a first state, in which the shutter assembly is configured to allow a first amount of ambient light from the user's environment to pass through it toward the user, and the adaptive lens assembly is configured to impart a first wavefront divergence to the light passing through it; and a second state, in which the shutter assembly is configured to allow a second amount of ambient light from the user's environment to pass through it toward the user, and the adaptive lens assembly is configured to impart a second wavefront divergence to the light passing through it, wherein the second amount of ambient light is different from the first amount of ambient light, and the second wavefront divergence is different from the first wavefront divergence.

[0064] Example 58 is an optical system according to Example 57, wherein the specific rate at which the shutter assembly and the adaptive lens assembly synchronously switch between two or more states includes a rate greater than or equal to a minimum switching frequency.

[0065] Example 59 is an optical system according to Example 57 or 58, further comprising: an ambient light sensor configured to measure the intensity of ambient light from the user's environment, wherein the control circuit is communicatively coupled to the ambient light sensor and is further configured to determine a specific rate at which the shutter assembly and the adaptive lens assembly synchronously switch between two or more states based on data received from the ambient light sensor.

[0066] Example 60 is an optical system according to Example 58 or 59, wherein the minimum switching frequency is 120 Hz.

[0067] Example 61 is an optical system according to Example 57, wherein the first amount of ambient light includes the shutter assembly being configured to allow a maximum amount of ambient light from the user's environment to pass through it toward the user, and the first amount of wavefront divergence includes the adaptive lens assembly being configured to impart a minimum amount of wavefront divergence to light passing through it.

[0068] Example 62 is an optical system according to any of Examples 57 or 61, wherein, in the second state, the control circuit is configured to cause the projector to emit light representing virtual content that will be perceived by the user as being located at a first depth in front of the user.

[0069] Example 63 is an optical system according to Example 62, wherein the control circuit is configured to determine at least one of a second amount of ambient light and a second amount of wavefront divergence based on a first depth in front of the user at which the virtual content will be perceived by the user.

[0070] Example 64 is an optical system according to Example 62, wherein, in a first state, the control circuit is configured to cause the projector to emit light representing virtual content, which virtual content will be perceived by the user as being located at a second depth in front of the user, the second depth being greater than the first depth.

[0071] Example 65 is an optical system according to Example 64, wherein the second depth is substantially equal to optical infinity.

[0072] Example 66 is an optical system according to Example 62, wherein, in the first state, the control circuit is configured to cause the projector to not emit light.

[0073] Example 67 is an optical system according to Example 61, wherein the adaptive lens assembly is configured to impart a minimum wavefront divergence of approximately zero to light passing through it.

[0074] Example 68 is an optical system according to Example 57, wherein the second amount of ambient light is less than the first amount of ambient light, and the second wavefront divergence is greater than the first wavefront divergence.

[0075] Example 69 is an optical system as described in any of the above examples, wherein the second amount of ambient light includes a shutter assembly configured to allow a minimum amount of ambient light from the user's environment to pass through it toward the user, and the second amount of wavefront divergence includes the adaptive lens assembly configured to impart a maximum amount of wavefront divergence to light passing through it.

[0076] Example 70 is an optical system according to Example 56, wherein the control circuit is configured to cause the shutter assembly and the adaptive lens assembly to synchronously switch between different states in a manner that produces an inverse relationship between the amount of ambient light from a user's environment that is allowed to pass through the shutter assembly toward the user and the amount of wavefront divergence imparted by the adaptive lens assembly to light passing through the shutter assembly toward the user.

[0077] Example 71 is an optical system according to Example 56, wherein the control circuit is configured to alternate between at least two different operating modes, including: a first operating mode, in which the control circuit is configured to control the state of the shutter assembly and the state of the adaptive lens assembly in an asynchronous manner; and a second operating mode, in which the control circuit is configured to control the state of the shutter assembly and the state of the adaptive lens assembly in a synchronous manner.

[0078] Example 72 is an optical system according to Example 71, wherein, in a second operating mode, the control circuit is configured to synchronously switch the shutter assembly and the adaptive lens assembly between two or more states, including: a first state, in which the shutter assembly is configured to allow a first amount of ambient light from the user's environment to pass through it toward the user, and the adaptive lens assembly is configured to impart a first wavefront divergence to the light passing through it; and a second state, in which the shutter assembly is configured to allow a second amount of ambient light from the user's environment to pass through it toward the user, and the adaptive lens assembly is configured to impart a second wavefront divergence to the light passing through it, wherein the second amount of ambient light is different from the first amount of ambient light, and the second wavefront divergence is different from the first wavefront divergence.

[0079] Example 73 is an optical system according to Example 71, further comprising: one or more cameras configured to capture images of one or both of the user's eyes, wherein the control circuit is communicatively coupled to the one or more cameras and is further configured to alternate between at least two different operating modes based at least in part on data received from the one or more cameras.

[0080] Example 74 is an optical system according to Example 73, wherein the control circuit is further configured to: determine the depth of the user's eye gaze based on data received from one or more cameras; and alternate between at least two different operating modes based at least in part on the depth at which the user's eyes are determined to be gazed.

[0081] Example 75 is an optical system according to Example 71, wherein the control circuit is further configured to cause the projector to emit light representing virtual content.

[0082] Example 76 is an optical system according to Example 75, wherein the control circuit is further configured to: determine whether an accommodation-convergence mismatch for the virtual content exceeds a threshold; and in response to determining that the accommodation-convergence mismatch for the virtual content exceeds the threshold, alternate between at least two different operating modes.

[0083] Example 77 is an optical system according to Example 75, wherein the control circuit is further configured to alternate between at least two different operating modes based at least in part on the depth in front of the user at which the virtual content will be perceived by the user.

[0084] Example 78 is an optical system according to Example 71, wherein, in a first operating mode, the control circuit is configured to cause a state of at least one of the shutter assembly and the adaptive lens assembly to remain substantially fixed.

[0085] Example 79 is an optical system as described in any of the above examples, wherein at least one waveguide is further configured to allow ambient light from the user's environment to pass through it toward the user.

[0086] Example 80 is an optical system as described in any of the above examples, wherein at least one component of the shutter assembly includes at least one component located between at least one waveguide and the user's environment.

[0087] Example 81 is an optical system as described in any of the above examples, wherein at least one component of the shutter assembly includes at least one component located between at least one waveguide and the user.

[0088] Example 82 is an optical system as described in any of the above examples, wherein at least one component of the shutter assembly includes at least one component located between at least one waveguide and the adaptive lens assembly.

[0089] Example 83 is an optical system as described in any of the above examples, wherein at least one waveguide includes a plurality of waveguides.

[0090] Example 84 is an optical system comprising: a projector configured to emit light; at least one waveguide optically coupled to the projector and configured to receive light from the projector and redirect the light toward a user; a shutter assembly comprising at least one component positioned adjacent to the at least one waveguide, wherein the shutter assembly is selectively switchable between different states, in which the shutter assembly is configured to allow different amounts of ambient light from the user's environment to pass through it toward the user, respectively; an adaptive lens assembly positioned between the at least one waveguide and the user, wherein the adaptive lens assembly is selectively switchable between different states, in which the adaptive lens is configured to impart different amounts of wavefront divergence to light passing through it toward the user, respectively; and control circuitry that is communicated coupled to a projector, a shutter assembly, and an adaptive lens assembly, wherein a control circuit is configured to cause the shutter assembly and the adaptive lens assembly to synchronously switch between two or more states at a specific rate, the two or more states comprising: a first state in which the shutter assembly is configured to allow a first amount of ambient light from an environment of a user to pass through it toward the user, and the adaptive lens assembly is configured to impart a first amount of wavefront divergence to light passing through it; and a second state in which the shutter assembly is configured to allow a second amount of ambient light from an environment of the user to pass through it toward the user, and the adaptive lens assembly is configured to impart a second amount of wavefront divergence to light passing through it, wherein the second amount of ambient light is different from the first amount of ambient light, and the second amount of wavefront divergence is different from the first amount of wavefront divergence.

[0091] Example 85 is an optical system according to Example 84, wherein the second amount of ambient light is less than the first amount of ambient light, and the second wavefront divergence is greater than the first wavefront divergence.

[0092] Example 86 is an optical system according to Example 84, wherein the specific rate at which the shutter assembly and the adaptive lens assembly synchronously switch between two or more states includes a rate greater than or equal to a minimum switching frequency.

[0093] Example 87 is an optical system according to Example 84, wherein, in a second state, the control circuit is configured to cause the projector to emit light representing virtual content that will be perceived by the user as being located at a first depth in front of the user, and wherein the control circuit is configured to determine at least one of a second amount of ambient light and a second amount of wavefront divergence based on the first depth in front of the user at which the virtual content will be perceived by the user.

[0094] Example 88 is an optical system according to Example 84, wherein at least one component of the shutter assembly includes at least one component located between at least one waveguide and the user.

[0095] Example 89 is an optical system comprising: a projector configured to emit light; at least one waveguide optically coupled to the projector and configured to receive light from the projector and redirect the light toward a user; a shutter assembly comprising at least one component positioned adjacent to at least one waveguide, wherein the shutter assembly is controllable to allow a variable amount of ambient light from the user's environment to pass through it toward the user; an adaptive lens assembly positioned between at least one waveguide and the user, wherein the adaptive lens assembly is controllable to impart a variable amount of wavefront divergence to light passing through it toward the user; and a control circuit communicatively coupled to the projector, the shutter assembly, and the adaptive lens assembly, wherein the control circuit is configured to synchronously: cause the adaptive lens assembly to change the amount of wavefront divergence imparted to light passing through it toward the user; and cause the shutter assembly to change the amount of ambient light from the user's environment that is allowed to pass through it toward the user inversely to the amount of wavefront divergence imparted to light passing through it by the adaptive lens assembly.

[0096] Example 90 is an optical system comprising: a projector configured to emit light; at least one waveguide optically coupled to the projector and configured to receive light from the projector and redirect the light toward a user; a shutter assembly comprising at least one component positioned adjacent to at least one waveguide, wherein the shutter assembly is selectively switchable between different states in which the shutter assembly is configured to respectively allow different amounts of ambient light from the user's environment to pass through it toward the user; an adaptive lens assembly positioned between at least one waveguide and the user, wherein the adaptive lens assembly is selectively switchable between different states in which the adaptive lens is configured to respectively impart different amounts of wavefront divergence to light passing through it toward the user; and a control circuit communicatively coupled to the projector, the shutter assembly, and the adaptive lens assembly, wherein the control circuit is configured to cause the shutter assembly and the adaptive lens assembly to synchronously switch between different states in a manner that produces an inverse relationship between the amount of ambient light from the user's environment allowed to pass through it toward the user by the shutter assembly and the amount of wavefront divergence imparted by the adaptive lens assembly to light passing through it toward the user.

[0097] Example 91 is an optical system comprising: a projector configured to emit light; at least one waveguide optically coupled to the projector and configured to receive light from the projector and redirect the light toward a user; a shutter assembly comprising at least one component positioned adjacent to the at least one waveguide, wherein the shutter assembly is selectively switchable between different states, wherein the shutter assembly is configured to respectively allow different amounts of ambient light from the user's environment to pass through it toward the user; an adaptive lens assembly positioned between the at least one waveguide and the user, wherein the adaptive lens assembly is selectively switchable between different states in different states , wherein the adaptive lens is configured to impart different amounts of wavefront divergence to light passing through it toward a user; and a control circuit that is communicatively coupled to the projector, the shutter assembly, and the adaptive lens assembly, wherein the control circuit is configured to alternate between at least two different operating modes, the at least two different operating modes comprising: a first operating mode, in which the control circuit is configured to control the state of the shutter assembly and the state of the adaptive lens assembly in an asynchronous manner; and a second operating mode, in which the control circuit is configured to control the state of the shutter assembly and the state of the adaptive lens assembly in a synchronous manner.

[0098] Example 92 is a non-transitory computer-readable medium storing instructions that, when executed by one or more processors, cause the one or more processors to perform one or more of the operations performed by the control circuit of any of the above examples.

[0099] Many benefits over conventional technologies are achieved through the present disclosure. Various embodiments described herein provide a compact time-multiplexed display that can apply refractive power to virtual image light to provide virtual content at various depths while undistorting world light. Various embodiments described herein also provide an adaptive lens assembly including a polarization-selective lens stack. In some embodiments, the polarization-selective lens stack includes birefringent lenses, such as Fresnel birefringent lenses, and isotropic lenses that are in contact with each other. Such components can be compact (e.g., can have a reduced thickness) and / or lightweight. These components can also potentially provide various advantageous optical functions, such as high bandwidth, increased switching speed, reduced chromatic aberration, increased ease of alignment, and / or variable refractive power. Some embodiments of the present disclosure provide replacement of conventional front adaptive lens assemblies with shutter assemblies, resulting in smaller / lighter form factors and increased power savings. In addition, various embodiments described herein can provide adaptive lens assemblies with relatively small amounts of leaked light, which otherwise may result in "ghost" images. Other benefits of the present disclosure will be apparent to those skilled in the art. BRIEF DESCRIPTION OF THE DRAWINGS

[0100] Figure 1An augmented reality (AR) scene as viewed through a wearable AR device according to embodiments described herein is shown.

[0101] Figure 2 An example of a display system including a pair of adaptive lens assemblies is shown.

[0102] Figure 3A The invention shows the use of an adaptive lens to display virtual content to a user at a virtual depth plane. Figure 2 An example of a display system.

[0103] Figure 3B Illustration of providing a user with a view of real-world content through an adaptive lens Figure 2 An example of a display system.

[0104] FIG. 4A to FIG. 4C One or more general features of an AR device according to the present disclosure are shown.

[0105] Figure 5 A schematic diagram of a wearable AR device according to the present disclosure is shown.

[0106] Fig. 6A A cross-sectional view of an example polarization-selective lens stack including a birefringent lens and an isotropic lens is shown.

[0107] Figure 6B The operation of passing linearly polarized light having a first polarization through it is shown. Fig. 6A Polarization selective lens stack.

[0108] Figure 6C The operation of passing linearly polarized light having a second polarization through it is shown. Fig. 6A Polarization selective lens stack.

[0109] Fig. 7A Shows an annotated parameter Fig. 6A Polarization selective lens stack.

[0110] Figure 7B Cross-sectional and top views of an example of a polarization-selective lens stack including a birefringent Fresnel lens and an isotropic lens are shown.

[0111] Fig. 8A A cross-sectional view of an example adaptive lens assembly including a polarization-selective lens stack coupled to a switchable wave plate including twisted nematic liquid crystal is shown.

[0112] Figure 8B Shown include Fig. 8A The switchable wave plate of twisted nematic liquid crystal of the adaptive lens assembly is shown.

[0113] Fig. 9AA cross-sectional view of an example adaptive lens assembly comprising a first polarization selective lens stack coupled to a first switchable wave plate comprising twisted nematic liquid crystal and a second polarization selective lens stack coupled to a second switchable wave plate comprising twisted nematic liquid crystal is shown.

[0114] FIG. 9B to FIG. 9E The invention shows the operation of the optical system in different configurations configured to apply different refractive powers. Fig. 9A An example of an adaptive lens assembly.

[0115] Fig.10 A cross-sectional view of an example display device including a waveguide assembly interposed between first and second adaptive lens assemblies each having a polarization-selective lens stack is shown.

[0116] Fig.11A A cross-sectional view of an example display device is shown including a waveguide assembly interposed between a shutter and a linear polarizer on a first side and an adaptive assembly having a polarization-selective lens stack on a second side.

[0117] Fig. 11B Shows Fig.11A A waveguide component of a display device includes a cholesteric liquid crystal and is configured to outcouple circularly polarized light.

[0118] Fig. 11C The operation in the configuration for viewing the world image is shown. Fig.11A An example display device.

[0119] Fig.11D FIG. 1 shows an example of an operation in a configuration for viewing a virtual image. Fig.11A An example display device.

[0120] Fig. 12A An example of a display device having a single adaptive lens assembly on the user side of the eyepiece is shown in accordance with some embodiments of the present disclosure.

[0121] Fig. 12B An example of a display device operating according to a first state according to some embodiments of the present disclosure is shown.

[0122] Fig. 12C An example of a display device operating according to a second state according to some embodiments of the present disclosure is shown.

[0123] Fig.13 A method of operating an optical system according to some embodiments of the present disclosure is shown.

[0124] Fig.14 A method of operating an optical system according to some embodiments of the present disclosure is shown.

[0125] Fig.15 An example execution of a method of operating an optical system according to some embodiments of the present disclosure is shown.

[0126] Fig.16A An example of a display device operating according to a first state according to some embodiments of the present disclosure is shown.

[0127] Fig. 16B An example of a display device operating according to a second state according to some embodiments of the present disclosure is shown.

[0128] Fig. 16C An example of a display device operating according to a third state according to some embodiments of the present disclosure is shown.

[0129] Fig.17 A simplified computer system is shown according to embodiments described herein. DETAILED DESCRIPTION

[0130] An optical see-through (OST) augmented reality (AR) device can improve the virtual content presented to a user by applying optical power to virtual image light (i.e., light associated with a virtual image) using one or more adaptive lens assemblies arranged within an optical stack. One problem with such a configuration is that optical power must also be applied to the world light (i.e., light associated with world objects) passing through it, causing distortion of the perceived world objects and thereby impairing the user experience. Some embodiments described herein overcome these and other problems by providing various shutter elements arranged within an optical stack that can be activated sequentially to produce a result in which world light passes through the AR device without distortion and the virtual image light is given optical power from the adaptive lens assemblies as needed.

[0131] Figure 1 An AR scene as viewed through a wearable AR device according to an embodiment described herein is shown. An AR scene 100 is depicted in which a user of the AR technology sees a real-world park-like setting 106 featuring people, trees, buildings, and a concrete platform 120 in the background. In addition to these items, the user of the AR technology also perceives that he "sees" a robotic statue 110 standing on the real-world platform 120, and a flying cartoon-like avatar character 102 that appears to be an avatar of a bumblebee, even though these elements (character 102 and statue 110) do not exist in the real world. Due to the extreme complexity of human visual perception and the nervous system, it is challenging to produce virtual reality (VR) or AR technology that promotes a comfortable, natural-feeling, rich presentation of virtual image elements among other virtual or real-world image elements.

[0132] Figure 2An example of a display device 200 is shown, e.g., a wearable display device, including one or more adaptive lens assemblies having a polarization-selective lens stack, e.g., a pair of adaptive lens assemblies 204, 208 in an optical path 216 inserted by a waveguide assembly 212. As described herein, the waveguide assembly 212 may include a waveguide configured to propagate light (e.g., visible light) under total internal reflection and couple out the light on an optical axis extending from a light output surface of the waveguide (e.g., a major surface of the waveguide) (e.g., in a direction perpendicular to the light output surface of the waveguide). In some embodiments, the light may be coupled out by a diffraction grating. Each of the adaptive lens assemblies 204, 208 may be configured to at least partially transmit the outcoupled light passing therethrough. In the illustrated embodiment, each of the adaptive lens assemblies 204, 208 may be configured to receive the outcoupled light from the waveguide assembly 212 and to converge or diverge the outcoupled light in the direction of the optical axis. Each of the adaptive lens assemblies 204, 208 includes a polarization-selective lens stack including a birefringent lens and an isotropic lens in contact with each other, wherein the contact surfaces of the birefringent lens and the isotropic lens form a conformal interface therebetween. Each of the adaptive lens assemblies 204, 208 is configured to selectively switch between a plurality of states having different refractive powers. That is, each of the adaptive lens assemblies 204, 208 is configured to selectively switch between a plurality of states, wherein the respective adaptive lens assemblies are configured to impart a different amount of wavefront divergence or wavefront convergence to the light passing through it. Each of the adaptive lens assemblies 204, 208 may also be configured to change the polarization state of the outcoupled light passing through it when activated (e.g., electrically activated).

[0133] As used herein, an adaptive lens assembly refers to a lens assembly having at least one optical property that can be adjusted, e.g., reversibly activated and deactivated, using an external stimulus. Example optical properties that can be reversibly activated and deactivated include, among other properties, optical power (focal length), phase, polarization, polarization selectivity, transmittance, reflectivity, birefringence, and diffraction properties, among others. In various embodiments, the adaptive lens assembly is capable of electrically changing the optical power and polarization state of light passing through it.

[0134] In the illustrated embodiment, each of a pair of adaptive lens assemblies 204, 208 is configured to selectively switch between at least two states, wherein in a first state, each adaptive lens assembly is configured to pass outcoupled light passing therethrough without changing its polarization state, and in a second state, each adaptive lens assembly is configured to change the polarization state of outcoupled light passing therethrough. For example, in the second state, each of the adaptive lens assemblies 204, 208 reverses the handedness of circularly polarized light, while in the first state, each of the adaptive lens assemblies 204, 208 maintains the handedness of circularly polarized light.

[0135] Still reference Figure 2 , the display device 200 may also include a waveguide assembly 212 inserted between a pair of adaptive lens assemblies 204, 208. Each of the waveguide assemblies 204, 208 may be configured to propagate light under total internal reflection in a lateral direction parallel to a major surface of the waveguide. Each of the waveguide assemblies 204, 208 may also be configured to couple out light, for example, in a direction perpendicular to the major surface of the waveguide.

[0136] Still reference Figure 2 , a first adaptive lens assembly 204 of a pair of adaptive lens assemblies is disposed on a first side of a waveguide assembly 212, e.g., a side of the world viewed by a user, and a second adaptive lens assembly 208 of a pair of lens assemblies is disposed on a second side of the waveguide assembly 212, e.g., a side of the user's eye. As described below, the pair of adaptive lens assemblies 204, 208 as configured provide the user with virtual content from the waveguide assembly 212, as well as a view of the real world at multiple virtual depth planes. In some embodiments, due to the presence of the pair of adaptive lens assemblies 204, 208, there is little or no distortion. Upon activating the first and second adaptive lens assemblies 204, 208, virtual content and a view of the real world are provided to the user, as described below with respect to Figure 3A and Figure 3B as described.

[0137] Figure 3A and Figure 3BAn example of display device 300A, 300B is shown, each display device includes an adaptive lens assembly in operation to output image information to a user. Display devices 300A, 300B may correspond to the same display device at different times and / or in different states. In some embodiments, display devices 300A, 300B in an unpowered state are structurally identical. Display device 300A is used herein to describe outputting a virtual image to a user, while display device 300B is used herein to describe sending a real-world image to a user by display device 300B. Display devices 300A, 300B include a pair of adaptive lens assemblies 204, 208, which are configured to be electrically activated by, for example, applying a voltage or current. In some embodiments, in a deactivated state, for example, when no voltage or current is applied, each of the first adaptive lens assembly 204 and the second adaptive lens assembly 208 has a low, for example, about zero, refractive power. In some embodiments, in an activated state, for example, when a voltage or current is applied, the first adaptive lens assembly 204 on the world side can provide a first net refractive power (P net1 ), for example, a positive refractive power. When in the activated state, the second adaptive lens assembly 208 on the user side can provide a second net refractive power (P) having a second sign. net2 ), for example, negative refractive power. However, embodiments are not limited thereto, and in other embodiments, the first adaptive lens assembly 200A and the second adaptive lens assembly 200B provide refractive power in the deactivated state and provide substantially zero refractive power when activated.

[0138] Figure 3A 304 according to some embodiments. Figure 2 As described above, the waveguide assembly 212 inserted between the pair of adaptive lens assemblies 204, 208 includes a waveguide configured to receive light containing virtual image information and propagate the light under total internal reflection. The waveguide assembly 212 is also configured to couple light toward the user's eyes through, for example, a diffraction grating. The coupled light passes through the user-side adaptive lens assembly 208 before entering the user's eyes. When activated, the user-side adaptive lens assembly 208 has a second net refractive power P net2 , which may have a negative value so that the user sees a virtual image at the virtual depth plane 304 .

[0139] In some embodiments, the second net refractive power P net2 can be electrically adjusted to adjust the second net refractive power (P net2), thereby adjusting the distance to the virtual depth plane 304. For example, when the virtual object "moves" closer and farther relative to the user's eyes in the virtual three-dimensional space, the second net refractive power P of the user-side adaptive lens assembly 208 net2 The distance to the virtual depth plane 304 may be adjusted accordingly so that the virtual depth plane 304 adjusts to track the virtual object. As a result, the user may experience relatively little or no accommodation / convergence mismatch that exceeds an acceptable threshold. In some embodiments, the magnitude of the distance to the virtual depth plane 304 may be adjusted in separate steps, while in some other embodiments, the magnitude of the distance to the virtual depth plane 304 may be adjusted continuously.

[0140] Figure 3B An illustration showing providing a view of real-world content to a user according to some embodiments Figure 2 An example of a display system. The adaptive lens assembly 208 on the user side is activated to have a second net refractive power (P net2 ) to display virtual content at the virtual depth plane 304, the light from the real world passing through the user-side adaptive lens component 208 can also be based on the P of the activated user-side adaptive lens component 208. net2 As a result, objects in the real world may appear out of focus or distorted. To mitigate such distortion, according to an embodiment, when activated, the adaptive lens assemblies 204, 208 may be configured to include refractive powers with opposite signs. In some embodiments, light passing through the adaptive lens assemblies 204, 208 converges or diverges according to a combined refractive power having an amplitude of about the first net refractive power P of the world-side and user-side adaptive lens assemblies 204, 208, respectively. net1 and the second net refractive power P net2 In some embodiments, waveguide assembly 212 may also have a refractive power and adaptive lens assembly 208 may be configured to account for the distortion caused by both lens assembly 204 and waveguide assembly 212. For example, the refractive power of adaptive lens assembly 208 may be opposite in sign to the sum of the refractive powers of adaptive lens assembly 204 and waveguide assembly 212.

[0141] In some embodiments, the world side adaptive lens assembly 204 is configured to have a first net refractive power P net1 , the first net refractive power P net1 The second net refractive power P of the adaptive lens assembly 208 on the user side is close to or equal to the second net refractive power P of the adaptive lens assembly 208 on the user side. net2 The magnitudes of are the same and have opposite signs. Therefore, when the two adaptive lens assemblies 204, 208 are activated simultaneously, objects in the real world appear to be relatively unaffected by the refractive power of the user-side adaptive lens assembly 208 provided for displaying virtual content.

[0142] In some embodiments, the first adaptive lens assembly 204 can be configured such that, when activated, the first net refractive power P net1 The second net refractive power P of the user-side adaptive lens assembly 208 net2 Dynamic matching. For example, the second net refractive power P of the adaptive lens assembly 208 on the user side net2 When the first net refractive power P of the world-side adaptive lens assembly 204 is adjusted to track a moving virtual object in a virtual three-dimensional space, net1 can be dynamically adjusted so that the combined refractive power P = P net1 +P net2 The magnitude of can be kept smaller than a predetermined value. Therefore, according to an embodiment, by utilizing the first net refractive power (P net1 ) to compensate for the second net refractive power (P net2 ), the second net refractive power (P net2 ) may have a negative value so that the combined refractive power P = P net1 +P net2 Keeping it small can prevent objects in the real world from being unacceptably out of focus. As described in more detail below, in some embodiments, the wearable display device may include a waveguide component and a user-side adaptive lens component that are functionally equivalent to or similar to the waveguide component 212 and the user-side adaptive lens component 208, respectively, but may not include a world-side adaptive lens component similar to the world-side adaptive lens component 204. Instead, as described in more detail below, in these embodiments, the display device may include one or more shutter elements, and may be configured to control such one or more shutter elements in synchronization with the user-side adaptive lens in some manner so that objects in the real world are not presented unacceptably out of focus through the refractive power imparted by the user-side adaptive lens.

[0143] Figure 4A 4 shows one or more general features of an AR device 400 according to the present disclosure. Figure 4AAs shown, AR device 400 includes eyepiece 402 and adaptive lens assembly 405, which can be functionally equivalent or similar to waveguide assembly 212 and user-side adaptive lens assembly 208, respectively, as described above. During operation, projector 414 of AR device 400 can project virtual image light 423 (i.e., light associated with a virtual image) onto eyepiece 402, which can cause a light field (i.e., an angular representation of virtual content) to be projected onto the user's retina in a manner such that the user perceives the corresponding virtual content as being positioned at a certain location within the user's environment. For example, the user can perceive character 102 as being positioned at or near a first virtual depth and statue 110 as being positioned at or near a second virtual depth. Although the AR device 400 may include only one adaptive lens assembly 405 (e.g., positioned on the user side of the eyepiece 402, i.e., the side of the eyepiece 402 closest to the user's eye), such an adaptive lens assembly may be capable of imparting a plurality of different non-zero refractive powers to light passing therethrough. That is, the adaptive lens assembly 405 may be capable of imparting a plurality of different amounts of at least one of wavefront divergence and collimation to light passing therethrough.

[0144] The AR device 400 may also include one or more shutter elements 403 coupled to the world side of the eyepiece 402 (the side of the eyepiece 402 farthest from the user's eyes and closest to the world object 430) and / or the user side of the eyepiece 402. By sequentially electrically activating different elements / layers of the shutter element 403 as described herein, world light 432 associated with the world object 430 can pass through the AR device 400 with zero net refractive power applied by the lens assembly 405, and virtual image light 423 can pass through with a non-zero (e.g., negative) net refractive power applied by the lens assembly 405. Example dimming components that may be represented or included in the shutter element 403 and other shutter components described herein are described in U.S. patent application No. 62 / 725,993 (attorney case number 101782-005600US-1083563) filed on August 31, 2018, U.S. patent application No. 16 / 557,706 filed on August 30, 2019, and international patent application No. PCT / US2019 / 051188 filed on September 13, 2019, all of which are incorporated herein by reference in their entirety.

[0145] In some embodiments, AR device 400 may include ambient light sensor 434 configured to detect world light 432. Ambient light sensor 434 may be positioned so that world light 432 detected by ambient light sensor 434 is similar to and / or representative of world light 432 impinging on AR device 400 (e.g., shutter element 403, eyepiece 402, and / or lens assembly 405). In some embodiments, ambient light sensor 434 may be configured to detect spatially resolved light values ​​corresponding to different pixels of the field of view of AR device 400. In some embodiments, or in the same embodiment, ambient light sensor 434 may be configured to detect global light values ​​corresponding to an average light intensity or a single light intensity of world light 432. The detected ambient light may be used by AR device 400 to determine a shutter frequency at which AR device 400 alternates between operating according to a first state or a second state. In some instances, the shutter frequency may exceed a flash fusion threshold so that the shutter may not be easily perceived by the user. For example, the shutter frequency may be at least 120 Hz (e.g., 160 Hz or 200 Hz).

[0146] Figure 4B An AR device 400 is shown operating according to a first state in accordance with some embodiments of the present disclosure. When operating according to the first state, the projector 414 is turned off and one or more of the shutter elements 403 are electrically activated so that world light 432 passes through the AR device 400 with zero net refractive power applied by the lens assembly 405. As will be shown below, this is accomplished using a world-side polarizer of the shutter element 403 that linearly polarizes the world light 432 along a first axis, a world-side switchable wave plate of the shutter element 403 that rotates the polarization of the world light 432 by 90 degrees, and a user-side polarizer of the shutter element 403 that linearly polarizes the world light 432 along a second axis perpendicular to the first axis.

[0147] In some embodiments, one or more components of shutter element 403 are considered to be subcomponents of (i.e., considered to be included in) lens assembly 405. For example, a user-side polarizer of shutter element 403 can be considered to be a subcomponent of lens assembly 405. In such embodiments, when AR device 400 operates according to the first state, lens assembly 405 is considered to be switched, activated, and / or controlled into a state that applies zero optical power to light passing therethrough.

[0148] Figure 4CAn AR device 400 is shown operating according to a second state in accordance with some embodiments of the present disclosure. When operating according to the second state, the projector 414 is turned on and one or more of the shutter elements 403 are electrically activated so that the world light 432 is completely or at least partially reduced, blocked, or dimmed, and the virtual image light 423 passes through the AR device 400 with a non-zero net refractive power applied by the lens assembly 405. As will be shown below, this is accomplished using a world-side polarizer of the shutter element 403 that linearly polarizes the world light 432 along a first axis, a user-side polarizer of the shutter element 403 that linearly polarizes the world light 432 and the virtual image light 423 along a second axis perpendicular to the first axis, and a user-side switchable wave plate of the shutter element 403 that rotates the polarization of the virtual image light 423 by 90 degrees.

[0149] Similar to reference Figure 4B As described above, in some embodiments, one or more components of shutter element 403 are considered to be subcomponents of lens assembly 405 (i.e., considered to be included in lens assembly 405). For example, the user-side polarizer of shutter element 403 can be considered to be a subcomponent of lens assembly 405. In such embodiments, when AR device 400 operates according to the second state, lens assembly 405 is considered to be switched, activated, and / or controlled to a state that applies a non-zero refractive power to light passing through it. In some examples (e.g., reference to Fig. 11C and Fig.11D Examples described), the polarized eyepiece can also be switched, activated, and / or controlled with each state so that the refractive power applied to the light it couples out can be varied.

[0150] Figure 5A schematic diagram of a wearable AR device 500 according to the present disclosure is shown. The AR device 500 may include a left eyepiece 502A, a left shutter element 503A, and a left lens assembly 505A arranged in a side-by-side configuration and a right eyepiece 502B, a right shutter element 503B, and a right lens assembly 505B also arranged in a side-by-side configuration. In some embodiments, the AR device 500 includes one or more sensors, including, but not limited to: a left front facing world camera 506A, which is directly attached to or near the left eyepiece 502A; a right front facing world camera 506B, which is directly attached to or near the right eyepiece 502B; a left facing world camera 506C, which is directly attached to or near the left eyepiece 502A; a right facing world camera 506D, which is directly attached to or near the right eyepiece 502B; a left eye tracker, which is positioned to observe the user's left eye; a right eye tracker, which is positioned to observe the user's right eye; and an ambient light sensor 534. In some embodiments, the AR device 500 includes one or more image projection devices, such as a left projector 514A, which is optically linked to the left eyepiece 502A, and a right projector 514B, which is optically linked to the right eyepiece 502B.

[0151] Some or all of the components of AR device 500 may be head-mounted so that the projected images can be viewed by the user. Figure 5 All components of the AR device 500 are shown mounted to a single device (e.g., a single head-mounted device) that can be worn by a user. In another embodiment, one or more components of the processing module 550 are physically separated from other components of the AR device 500 and are communicatively coupled to the other components of the AR device 500 through one or more wired and / or wireless connections. For example, the processing module 550 may include a local module 552 on a head-mounted portion of the AR device and a remote module 556 that is physically separated from the local module 552 and communicatively linked to the local module 552. The remote module 556 can be mounted in a variety of configurations, such as being fixedly attached to a frame, fixedly attached to a helmet or hat worn by a user, embedded in headphones, or otherwise removably attached to the user (e.g., in a backpack-type configuration, in a belt-coupled configuration, etc.).

[0152] The processing module 550 may include a processor and associated digital memory, such as non-volatile memory (e.g., flash memory), both of which may be used to assist in the processing, caching, and storage of data. The data may include data captured from a sensor (which may, for example, be operatively coupled to the AR device 500) or otherwise attached to the user, such as a camera 506, an ambient light sensor 534, an eye tracker, a microphone, an inertial measurement unit, an accelerometer, a compass, a GPS unit, a radio device, and / or a gyroscope. For example, the processing module 550 may receive one or more images 520 from the camera 506. In particular, the processing module 550 may receive one or more left front images 520A from a left-front facing world camera 506A, one or more right front images 520B from a right-front facing world camera 506B, one or more left side images 520C from a left-front facing world camera 506C, and one or more right side images 520D from a right-front facing world camera 506D. In some embodiments, the one or more images 520 may include a single image, a pair of images, a video including an image stream, a video including a paired image stream, etc. One or more images 520 may be generated periodically and sent to processing module 550 when AR device 500 is powered on, or may be generated in response to instructions sent by processing module 550 to one or more of the cameras. As another example, processing module 550 may receive ambient light information from ambient light sensor 534. As another example, processing module 550 may receive gaze information from an eye tracker. As another example, processing module 550 may receive image information (e.g., image brightness values) from one or both of projectors 514.

[0153] The eyepieces 502A, 502B may include a transparent or semi-transparent waveguide, respectively, configured to guide and couple out light from the projectors 514A, 514B. In particular, the processing module 550 may cause the left projector 514A to output the left virtual image light 522A to the left eyepiece 502A, and may cause the right projector 514B to output the right virtual image light 522B to the right eyepiece 502B. In some embodiments, each of the eyepieces 502 may include a plurality of waveguides corresponding to different colors and / or different depth planes. In some embodiments, the shutter element 503 may be coupled to the eyepiece 502 and / or integrated with the eyepiece 502. For example, the shutter element 503 may be included in a multi-layer eyepiece and may form one or more layers that make up one of the eyepieces 520. In some embodiments, the processing module may electrically activate the shutter elements 503A, 503B using the left shutter control signal 519A and the right shutter control module 519B, respectively. For example, the processing module 550 may apply different voltages to the shutter control signal 519 to cause the AR device 500 to alternate between presenting world light and virtual image light to the user.

[0154] Cameras 506A, 506B can be positioned to capture images that substantially overlap the fields of view of the user's left and right eyes, respectively. Therefore, the arrangement of camera 506 can be near the user's eyes, but not too close to blur the user's field of view. Alternatively or additionally, cameras 506A, 506B can be positioned to align with the coupling-in positions of virtual image lights 522A, 522B, respectively. Cameras 506C, 506D can be positioned to capture images on one side of the user, for example, within the user's peripheral vision or outside the user's peripheral vision. One or more images 520C, 520D captured using cameras 506C, 506D do not necessarily need to overlap with one or more images 520A, 520B captured using cameras 506A, 506B.

[0155] Polarization selective lens stack comprising a birefringent lens and an isotropic lens for an adaptive lens assembly

[0156] Various embodiments described herein provide an adaptive lens assembly including a polarization-selective lens stack. In certain embodiments, the polarization-selective lens stack includes a birefringent lens, e.g., a Fresnel birefringent lens, and an isotropic lens in contact with each other. Such assemblies can be compact (e.g., can have a reduced thickness) and / or lightweight. These assemblies can also potentially provide various advantageous optical functions, such as high bandwidth, increased switching speed, reduced chromatic aberration, increased ease of alignment, and / or variable refractive power. In addition, the various embodiments described herein can provide an adaptive lens assembly with a relatively small amount of leaked light, which otherwise may result in a "ghost" image. According to various embodiments, the adaptive assembly includes a polarization-selective lens stack having a birefringent lens and an isotropic lens, as described herein.

[0157] refer to Fig. 6A In order to provide images at multiple depth planes with high efficiency over a wide range of the visible spectrum, an adaptive lens assembly according to various embodiments includes a polarization-selective lens stack 600 configured to apply polarization-dependent refractive power to linearly polarized light. The polarization-selective lens stack 600 may include a birefringent lens 604 having an optical axis 602 extending in a transverse direction (e.g., an x-direction or a y-direction) perpendicular to a direction of light propagation (e.g., a z-direction). The birefringent lens 604 has a birefringent index Δn. The birefringent index Δn is related to an extraordinary refractive index n of the birefringent lens 604. e With ordinary refractive index n o The birefringent lens 604 may have a curvature radius R1 so that it is configured to apply a first refractive power p1 to light passing through it and having a polarization direction parallel to the optical axis, and apply a second refractive power p2 to light passing through it and having a polarization direction perpendicular to the optical axis.

[0158] The polarization-selective lens stack 600 may additionally include a lens having a refractive index n c An isotropic lens 608 having a second radius of curvature R2 so as to be configured to apply a third refractive power p3 having a sign opposite to the first refractive power p1 and the second refractive power p2 to light passing therethrough.

[0159] In the illustrated embodiment, but not limited thereto, the extraordinary refractive index ne of the isotropic lens 608 has the same value as the ordinary refractive index n of the birefringent lens 604. o However, it will be appreciated that in some other embodiments, the extraordinary refractive index n e It can be compared with the ordinary refractive index n o different.

[0160] In the illustrated embodiment, but not limited thereto, the first radius of curvature R1 and the second radius of curvature R2 are substantially the same in magnitude R, while having opposite signs. In addition, since R1 and R2 are substantially the same in magnitude, the birefringent lens 604 and the isotropic lens 608 are in continuous contact along the interface having the radius of curvature R. That is, the contact surfaces of the birefringent lens 604 and the isotropic lens 608 form a conformal interface therebetween.

[0161] refer to Figure 6B , shows the polarization-selective lens stack 600 in operation when the incident light 612 (e.g., linearly polarized light) has a polarization direction parallel to the direction of the optical axis 602. In this case, since the light passing through the birefringent lens 604 experiences a refractive index n e The light passing through the isotropic lens 608 experiences a refractive index corresponding to n o The corresponding refractive index, and therefore the optical power applied by lens stack 600 to light, can be expressed as:

[0162]

[0163] Here, R represents the magnitude of the radius of the birefringent lens 604 and the isotropic lens 608 .

[0164] refer to Figure 6C , shows the polarization-selective lens stack 600 in operation when the incident light 616 (e.g., linearly polarized light) has a polarization direction perpendicular to the optical axis 602. In this case, since the light passing through the birefringent lens 604 experiences a refractive index n o The corresponding refractive index, which is the same as the refractive index experienced by light passing through isotropic lens 608, and the refractive power applied to the light by lens stack 600 can be expressed as:

[0165]

[0166] Here, R represents the magnitude of the radius of the birefringent lens 604 and the isotropic lens 608 .

[0167] Still reference FIG. 6A to FIG. 6C In some embodiments, the isotropic lens 608 may be formed of an isotropic material, such as glass, acrylic, etc. On the other hand, according to various embodiments, the birefringent lens 604 may be formed of or include a birefringent material, such as liquid crystal. For example, the birefringent lens 604 may include a transparent substrate, such as a glass substrate, on which liquid crystal (LC) molecules elongated in a lateral direction (e.g., x-direction or y-direction) perpendicular to the light propagation direction (e.g., z-direction) have been formed.

[0168] However, the embodiments are not limited thereto, and in other embodiments, the birefringent lens 604 may be formed of or include a suitable birefringent material other than LC. For example, the birefringent lens 604 may include, for example, BaB2O4, Be3Al2(SiO3)6, CaCO3 LiNbO3 TiO2 SiC, tourmaline, and ZrSiO4, to name a few.

[0169] Polarization selective lens including birefringent Fresnel lens and isotropic lens for adaptive lens assembly Stacking

[0170] As above relative to FIG. 6A to FIG. 6C As described, a lens stack comprising a birefringent lens (eg, a LC-based birefringent lens) and an isotropic lens can provide a polarization selective lens effect. In the following, a polarization selective lens stack comprising a liquid crystal-based birefringent lens configured as a Fresnel lens is described.

[0171] A Fresnel lens may, for example, include a thin plate-type lens including a partial prismatic structure formed by decomposing a conventional curved (e.g., spherical) lens into a set of segments, e.g., concentric annular segments, referred to as Fresnel zones. The Fresnel zones replace the continuous curvature of a continuous refractive lens with a set of surfaces of the same shape with discontinuities between them. A substantial reduction in thickness can be achieved by employing such partial segments, and a lens having a relatively large aperture can be manufactured using a smaller volume of material.

[0172] Fig. 7A Shows the above relative to FIG. 6A to FIG. 6CA cross-sectional side view of the depicted lens stack 600 is annotated with relevant optical dimensions, including a distance R to a given location on the birefringent lens 604 from a focal point, a radial distance A from a given location of a central axis (e.g., an optical axis) of the lens stack 600, an angle θ defined by the distances R and A, and a thickness d of a curved portion of the birefringent lens 604. As described above, in various embodiments, because the birefringent lens 604 and the isotropic lens 608 have substantially the same radius of curvature, the birefringent lens 604 and the isotropic lens 608 are in continuous contact along an interface having a radius of curvature R formed therebetween.

[0173] Figure 7B A cross-sectional side view 700A (top) and a top view 700B (bottom) of a lens stack 700 including a birefringent Fresnel lens 704 and a counterpart objective lens, such as an isotropic Fresnel lens 708, are shown. By using the Fresnel lens 704, the groove thickness d' of the curved portion of the birefringent lens 704 can be significantly reduced. Despite the significantly reduced thickness d', the lens stack 700 has a corresponding curvature, such as with respect to Fig. 7A The actual radius of curvature R of the conventional lens shown corresponds to the effective radius of curvature R. Thus, although not shown, the lens stack 700A additionally has a given Fresnel zone or groove 706 at a radial distance A from the central axis of the lens stack 700. k and the distances R and A k The angle θ is defined. Figure 7B In some embodiments shown, despite the grooves separating the Fresnel zones, the birefringent Fresnel lens 704 and the isotropic lens 708 are in continuous contact throughout the interface formed therebetween having an effective radius of curvature R. In some embodiments, consecutive Fresnel zones in the radially outward direction may have different radial distances A. k and different distances between adjacent grooves 706. For example, in the illustrated embodiment, the distance between adjacent Fresnel zones becomes smaller in the radially outward direction of the birefringent Fresnel lens 704. However, the embodiments are not limited thereto and in other embodiments, the radial distance A between consecutive Fresnel zones is k It may increase linearly with a constant distance between adjacent Fresnel zones while having different groove thicknesses within each zone to provide similar or the same optical effect as the illustrated embodiment.

[0174] refer to Figure 7B (Bottom) A birefringent Fresnel lens 704 is shown including a plurality of concentric Fresnel zones, according to some embodiments. The birefringent Fresnel lens 704 has a plurality of grooves 716 disposed at a radius A from the central axis. kThe boundary of the Fresnel zone 712 is formed at a distance represented by . According to various embodiments, the groove thickness d' of the birefringent lens 704 is designed so that the path length is a multiple of the design wavelength λ. This arrangement can produce a 2nm phase jump between regions that result in the same wavefront. The value of d' can be selected (e.g., optimized) to balance manufacturing tolerances and reduce or minimize aberrations that can arise from the sharp edges of the groove 716. In one example, the radius R of the kth Fresnel zone can be calculated by setting the thickness of the curved region to kd' by the following equation:

[0175]

[0176] wherein k represents the number of Fresnel zones calculated from the center of the lens, and wherein the groove thickness d′ is constant across the surface of the illustrated birefringent Fresnel lens 704 .

[0177] In some embodiments, the birefringent Fresnel lens 704 includes LC. The LC molecules can be aligned laterally, or have an elongation direction (e.g., y direction) that extends substantially in the lateral direction 720 indicated by the arrow. In addition, the arrangement direction of the LC molecules can be substantially uniform throughout the thickness of the birefringent Fresnel lens 704, without undergoing rotation. That is, the local director n of the LC molecules can be substantially constant laterally across the area of ​​the birefringent Fresnel lens 704, and substantially constant vertically across the thickness of the birefringent Fresnel lens 704 (e.g., in the z direction). The arrangement shown can, for example, be suitable for providing polarization selectivity for linearly polarized light. In these embodiments, linearly polarized light having a polarization direction parallel to the LC arrangement direction (e.g., y direction) can experience n. e or o One of the LC alignment directions, while linearly polarized light having a polarization direction perpendicular to the LC alignment direction (eg, x direction) can experience n e or o Thus, lens stack 700 applies an optical power of Δn / R to light having one linear polarization, while applying substantially zero optical power to light having the other linear polarization, as described above.

[0178] In various embodiments herein and throughout the specification, the birefringent Fresnel lens 704 can have an average, local, mean, median, maximum, or minimum birefringence Δn of 0.05-0.10, 0.15-0.20, 0.20-0.25, 0.25-0.30, 0.30-0.35, 0.35-0.40, 0.40-0.45, 0.45-0.50, 0.50-0.55, 0.55-0.60, 0.60-0.65, 0.65-0.70, or any value in any range defined by any of these values, e.g., 0.05-0.40. Additionally, the birefringent Fresnel lens 704 can have an intra-layer birefringence (Δn) range of 0.01-0.05, 0.05-0.10, 0.15-0.20, 0.20-0.25, 0.25-0.30, 0.30-0.35, 0.35-0.40, or any value within any range defined by any of these values.

[0179] In various embodiments herein and throughout the specification, birefringent Fresnel lens 704 has a thickness of approximately 0.1 μm-200 μm, 0.1-5 μm, 5-50 μm, 50-100 μm, 100-150 μm, 150-200 μm, or any range defined by these values, for example 5-200 μm.

[0180] Adaptive lens assembly comprising a polarization selective lens stack coupled to a switchable wave plate

[0181] To provide images at multiple depth planes with high efficiency over a wide range of the visible spectrum, an adaptive lens assembly according to various embodiments includes a polarization selective lens stack (e.g., FIG. 6A to FIG. 6C 600 of them Figure 7B 700 in ), which includes a birefringent lens and an isotropic lens. According to various embodiments, the adaptive lens assembly can be selectively switched between multiple states using different refractive powers. In the following, an adaptive lens assembly is disclosed, wherein the selective switching is performed by activating or deactivating a sliceable wave plate coupled to a polarization selective lens included in the adaptive lens assembly according to the embodiment.

[0182] refer to Fig. 8AIn some embodiments, the adaptive lens assembly 800A is configured to be activated or deactivated by using a switchable wave plate 804 including LC in the same optical path as the polarization selective lens stack 700 described above including a birefringent Fresnel lens 704 and an isotropic lens 708. The Fresnel lens 704 can be formed using LC or other birefringent materials. The adaptive lens assembly 800A can be selectively switched between different states by electrically activating and deactivating the switchable wave plate 804 (or otherwise changing the state of the wave plate, for example, by applying different voltages). Figure 8B One example of a switchable wave plate 804 is shown.

[0183] refer to Figure 8B In some embodiments, the switchable wave plate 802 may be a half-wave plate or polarization rotator including a layer 802 of unpolymerized twisted nematic (TN) liquid crystal (LC), or a reactive liquid crystal (RM) including TN LC molecules, which is configured to be switched when an electric field is applied across the thickness of the layer 802 of TN LC. The layer 802 of TN LC is disposed between a pair of transparent substrates 812. Each of the transparent substrates 812 has formed on an inner surface a conductive transparent electrode 816, 820. In some embodiments, the transparent electrodes 816, 820 may be used as substrates, and one or both of the substrates 812 may be omitted.

[0184] The surfaces of the transparent electrodes 816, 820 and / or the substrate 812 may be configured such that the TN LC molecules in contact with or directly adjacent to the upper electrode 816 tend to be oriented with their long axes extending in a first lateral direction, while the TN LC molecules in contact with or directly adjacent to the lower electrode 820 tend to be oriented with their long axes extending in a second lateral direction, which may cross, for example, to form an angle of about 90 degrees relative to the first lateral direction. Thus, the TN LC molecules between the electrodes 816, 820 are subject to twisting.

[0185] Still reference Figure 8B(Left), In operation, in the absence of an electric field across the TN LC layer 802 (deactivated state), the nematic directors of the TN LC molecules undergo a smooth 90 degree twist across the thickness of the TN LC layer 802. As shown, incident light 808 polarized in a first direction (the same direction as the LC molecules closest to the lower electrode 812) is incident in the TN LC layer 802. The twisted arrangement of the TN LC molecules within the TN LC layer 802 acts as an optical waveguide and rotates the plane of polarization by a quarter turn (90 degrees) before the light reaches the upper electrode 816. In this state, the TN LC layer 802 acts to shift the polarization direction of linearly polarized light passing through it from one linear polarization direction to another linear polarization direction. Thus, transmitted light 806A is polarized in a second direction (the same direction as the LC molecules closest to the upper electrode 816) that is opposite to the first direction.

[0186] On the other hand, when a voltage exceeding the threshold voltage of the TN LC switchable wave plate 804 (V>Vth) is applied across the electrodes 816, 820 (right actuated state), the TN LC molecules within the TN LC layer 802 tend to align with the generated electric field and the optical waveguide properties of the TN LC layer 802 described above with respect to the deactivated state are lost. In this state, the TN LC layer 802 serves to maintain the polarization direction of light passing through it. Therefore, the incident light 808 and the transmitted light 806B are polarized in the same first direction (the same direction as the LC molecules closest to the lower electrode 820). When the electric field is turned off, the TN LC molecules relax back to their twisted state, and the TN LC molecules of the TN LC layer 802 in the actuated state return to the configuration of the TN LC molecules of the TN LC layer 802 in the deactivated state (left).

[0187] Still reference Fig. 8A In operation, as described above, the polarization-selective lens stack 700 applies a lens refractive power to the incident light 820 passing through it, depending on the polarization direction of the incident light 820. After applying or not applying the refractive power to the incident light, depending on the relative polarization direction of the incident light, the light is incident on the switchable wave plate 804. As described above, the LC of the switchable wave plate 804 is configured so that when activated, e.g., electrically activated, the polarization of the linearly polarized light passing through it is maintained, and when deactivated, e.g., electrically deactivated, the polarization of the linearly polarized light passing through it is changed, e.g., flipped or rotated. That is, a linear vertically polarized (LVP) light beam is converted to a linear horizontally polarized (LHP) light beam and vice versa, or the polarization is maintained, depending on whether the switchable wave plate 804 is activated or deactivated.

[0188] In operation, the LC of the birefringent Fresnel lens 704 is configured so that when the polarization direction of the linearly polarized incident light 820 is parallel to the optical axis of the birefringent Fresnel lens 704, the polarization-selective lens stack 700 applies a refractive power thereto, as described above with respect to Figure 6B As described above, when the polarization direction of the linearly polarized incident light 820 is perpendicular to the optical axis, the polarization selective lens stack 700 applies substantially zero refractive power to it, as described above with respect to Figure 6C After passing through the birefringent lens stack 700, when activated, e.g., electrically activated, the polarization of the linearly polarized light passing through the switchable wave plate 804 is maintained, and when deactivated, e.g., electrically deactivated, the polarization of the linearly polarized light passing through the switchable wave plate 804 is flipped or rotated due to the rearrangement of the liquid crystal molecules.

[0189] about FIG. 8A to FIG. 8B , including with a wave plate ( Fig. 8A ) coupled to a passive polarization selective lens stack for switchably applying lens refractive power. The inventors have recognized that by arranging multiple such elements, an adaptive lens assembly with multiple different lens refractive powers can be formed. Therefore, in the following, embodiments of an adaptive waveplate lens assembly including multiple passive polarization selective lens stacks coupled to a waveplate are disclosed. Such an adaptive lens assembly can be integrated with a waveguide on the user side or the world side to form an adaptive waveplate lens assembly with respect to, for example, Figure 3A and Figure 3B Display device described.

[0190] Fig. 9A An example of an adaptive lens assembly 900 is shown, which includes multiple passive polarization selective lens stacks and multiple wave plates, which are alternately arranged to apply multiple (e.g., at least four) possible refractive powers to light passing through it. The adaptive lens assembly 900 includes, in the order of light passing through it, a first switchable wave plate (HWP1) 804-1, for example, a half-wave plate; a first polarization selective lens stack (L1) 700-1, a second switchable wave plate (HWP2) 804-2, for example, a half-wave plate; and a second polarization selective lens stack (L2) 700-2. Each of HWP1 804-1 and HWP2 804-2 is arranged in the same manner as above with respect to Fig. 8A and Figure 8B In addition, each of L1 700-1 and L2 700-2 is configured in a manner similar to that described above with respect to FIG. 6A to FIG. 6C , FIG. 7A to FIG. 7B and FIG. 8A to FIG. 8BThe first polarization selective lens stack 700-1 and the second polarization selective lens stack 700-2 are configured in a manner similar to that described. However, the first polarization selective lens stack 700-1 and the second polarization selective lens stack 700-2 have different optical axes, different curvatures (e.g., effective curvature radii) and / or different birefringence. That is, L1 700-1 has a first optical axis (extending in the vertical or y direction) and is configured to apply a first refractive power φ1 of Δn1 / R1 or substantially zero to light incident thereon having a polarization direction parallel or perpendicular to the optical axis, respectively, while 700-2 has a second optical axis (extending in the horizontal or x axis) and is configured to apply a second refractive power φ2 of Δn2 / R2 or substantially zero to light incident thereon having a polarization direction parallel or perpendicular to the optical axis, respectively.

[0191] FIG. 9B to FIG. 9E The corresponding HWP1 804-1 / HWP 804-2 deactivation (off / deactivation (off) ( Fig. 9B ), Activate(switch on) / Activate(switch on)( Fig. 9C ), turn off / on( Fig.9D ), and on / off ( Fig.9E 700-1). As described above, each of HWP1 804-1 and HWP2 804-2 can be turned off and on, or deactivated and activated, by removing and applying a voltage across the TN LC layer. Each of HWP1 804-1 and HWP2 804-2 is configured to change the polarization state of light passing through it, for example, rotate or reverse the polarization state, when electrically deactivated (off), and is configured to substantially pass light without changing the polarization state of light passing through it when activated (on). An electrical signal for switching each of HWP1 804-1 and HWP2 804-2, for example, a current signal or a voltage signal, can be provided by a switching circuit (not shown) electrically connected thereto. For illustrative purposes, hereinafter, a switching circuit similar to Figure 8B , HWP1 804-1 and HWP2 804-2 are TN LC cells having optical axes along the y and x axes at their two substrates, respectively. In the illustrated embodiment, the incident light 820 has a polarization parallel to the y direction, i.e., linear vertical polarization (LVP). However, it will be understood that the polarization axis of the incident light 820 can be polarized in a different direction, linear horizontal polarization (LHP), to achieve different refractive power states.

[0192] refer to Fig. 9B, each of HWP1 804-1 and HWP2 804-2 is in an off state and is configured to rotate the polarization of linearly polarized light having one of LVP and LHP into linearly polarized light having the other of LVP and LHP. Therefore, when passing through HWP1 804-1, incident light 820 having LHP is converted into light 824 having LHP incident on L1 700-1, which exerts substantially zero refractive power (φ1=0) due to the relative orthogonal orientation between the polarization of light 824 and the optical axis of L1 700-1. Thereafter, light 828 having LHP incident on HWP2 804-2 is converted into light 832 having LVP. L2 700-2 exerts substantially zero refractive power (φ2=0) due to the relative orthogonal orientation between the polarization of L2 700-2 and the optical axis of L2 700-2. In summary, the adaptive lens assembly 900 applies a net refractive power φ1+φ2 of approximately zero to the incident light 820 having LVP and does not change its polarization, thereby outputting light 836 having LVP.

[0193] refer to Fig. 9C , each of HWP1 804-1 and HWP2 804-2 is in an on state and is configured to maintain the polarization of linearly polarized light passing through it. Therefore, when passing through HWP1 804-1, the polarization of incident light 820 with LVP is maintained to light 824 incident on L1 700-1, which applies a refractive power (φ1) due to the relative parallel orientation between the polarization of light 824 and the optical axis of L1 700-1. Thereafter, the polarization of light 828 with LVP incident on HWP2 802-2 is maintained into light 832. L2 700-2 applies a substantially zero refractive power (φ2=0) due to the relative orthogonal orientation between the polarization of light 832 and the optical axis of L2 700-2. In summary, the adaptive lens assembly 900 applies a net refractive power φ1 + φ2 approximately equal to φ1 to the incident light 820 having LVP and outputs light 836 having LVP.

[0194] Referring to 9D, HWP1 804-1 is in an off state and is configured to rotate the polarization of linearly polarized light having one of LVP and LHP to linearly polarized light having the other of LVP and LHP, while HWP2 804-2 is in an on state and is configured to maintain the polarization of the linearly polarized light. Therefore, when passing through HWP1 804-1, incident light 820 having LVP is converted into light 824 having HVP incident on L1 700-1, which L1 700-1 applies substantially zero refractive power (φ1=0) due to the relative orthogonal orientation between the polarization of light 824 and the optical axis of L1 700-1. Thereafter, the polarization of light 828 having HVP passing through HWP2 802-2 is maintained into light 832. Light 832 incident on L2 700-2 has an HVP, and L2 700-2 exerts a refractive power (φ2) due to the relative parallel orientation between the polarization of light 832 and the optical axis of L2 700-2. In summary, adaptive lens assembly 900 exerts a net refractive power φ1+φ2 approximately equal to φ2 to incident light 820 having an LVP and outputs light 836 having an LHP.

[0195] refer to Fig.9E , HWP1 804-1 is in an on state and is configured to maintain the polarization of linearly polarized light, while HWP2 804-2 is in an off state and is configured to rotate the polarization of linearly polarized light having one of LVP and LHP to linearly polarized light having the other of LVP and LHP. Therefore, when passing through HWP1 804-1, the polarization of incident light 820 having LVP is maintained to light 824 having LVP incident on L1 700-1, which applies a refractive power (φ1) due to the relative parallel orientation between the polarization of light 824 and the optical axis of L1 700-1. Thereafter, light 828 having LVP passing through HWP2 804-2 is converted into light 832 having HVP. L2 700-2 applies a refractive power (φ2) due to the relative parallel orientation between the polarization of light 832 and the optical axis of L2 700-2. In summary, the adaptive lens assembly 900 applies a net refractive power φ1 + φ2 to the incident light 820 having an LVP and outputs light 836 having an LHP.

[0196] Therefore, if 9A to 9E As shown, for light with linear polarization, four possible net refractive powers (0, φ1, φ2, and φ1+φ2) can be imposed on the light passing through the adaptive lens assembly 900. By way of numerical example, for φ1=0.75D and φ2=1.5D for the design wavelength, net refractive powers of 0, 0.75D, 1.5D, and 2.25D can be obtained using the adaptive lens assembly 900.

[0197] Still combined Figure 3Aand Figure 3B refer to 9A to 9E In the illustrated embodiment, incident light 820 may represent a light beam incident on the world-side adaptive lens assembly 204 or the user-side adaptive lens assembly 208. By placing the adaptive lens assembly 900 on one or both sides, the above-mentioned, for example, relative to the user-side adaptive lens assembly 208 may be achieved according to various embodiments as described herein. Figure 3A and Figure 3B Display system as described.

[0198] A display device comprising an adaptive lens assembly having a polarization selective lens stack coupled to a non-polarizing waveguide assembly Display device

[0199] In the following example embodiments, a plurality of switchable polarization-selective lens stacks (eg, adaptive lens assembly 900, 9A to 9E ) have been integrated into display devices, for example, such as the above with respect to Figure 2 , Figure 3A ,and Figure 3B Display device described.

[0200] Fig.10 An example display device 1000 is shown that includes a waveguide assembly 1012 interposed between a first or front adaptive lens assembly (FLA) 1004 and a second or back adaptive lens assembly (BLA) 1008. The display device 1000 may be similar to that described above with respect to Figure 3A and Figure 3B In the illustrated embodiment, the BLA 1008 is similar to the display devices 300A, 300B described above. 9A to 9E The described adaptive lens assembly 900 is configured and includes a first switchable wave plate (HWP1) 804-1, a first polarization selective lens stack (L1) 700-1, a second switchable wave plate (HWP2) 804-2, and a second polarization selective lens stack (L2) 700-2. The first polarization selective lens stack 700-1 and the second polarization selective lens stack 700-2 have different, for example, orthogonal optical axes, curvatures (e.g., effective curvature radii), and / or different birefringences, so that L1 700-1 is configured to apply a first refractive power φ1 of n1 / R1 or substantially zero for light incident thereon having a polarization direction parallel or orthogonal to the optical axis, respectively, and L2 700-2 is configured to apply a second refractive power φ2 of n2 / R2 or substantially zero for light incident thereon having a polarization direction parallel or orthogonal to the optical axis, respectively.

[0201] FLA 1004 includes a third switchable wave plate (HWP3) 804-3, a third polarization selective lens stack (L3) 700-3, a fourth switchable wave plate (HWP4) 804-4, and a fourth polarization selective lens stack (L4) 700-4. The third polarization selective lens stack 700-3 and the fourth polarization selective lens stack 700-4 have different, for example, orthogonal optical axes, effective radii of curvature, and / or different birefringence, so that L3 700-3 is configured to apply a third refractive power φ3 of n3 / R3 or substantially zero for light incident thereon having a polarization direction parallel or orthogonal to the optical axis, respectively, and L4 700-4 is configured to apply a fourth refractive power φ4 of n4 / R4 or substantially zero for light incident thereon having a polarization direction parallel or orthogonal to the optical axis, respectively.

[0202] In various embodiments, the effective radii of curvature of L1 700-1 and L2 700-2 are such that φ1 and φ2 have a first sign, e.g., a positive sign, and the effective radii of curvature of L3 700-3 and L4 700-4 are such that φ3 and φ4 have a second sign opposite to the first sign, e.g., a negative sign. That is, while the three possible non-zero net refractive powers (φ1, φ2, and φ1+φ2) of the FLA 1004 may have one of a converging or diverging effect (e.g., converging), the three possible non-zero net refractive powers (φ3, φ4, and φ3+φ4) of the BLA 1008 may have the other of the converging or diverging effects (e.g., diverging). In the illustrated embodiment, the FLA 1004 and the BLA 1008 are configured to be substantially identical (e.g., one is concave and the other is convex, or vice versa, etc.), except for the curvature of the interface between the birefringent lens and the isotropic lens. In particular, the FLA 1004 and the BLA 1008 form mirror images about the waveguide assembly 1012. Thus, as configured, L1 804-1 and L3 804-3 have refractive powers φ1 and φ3, respectively, that are substantially equal in magnitude but opposite in sign, and L2 804-2 and L4 804-4 have refractive powers φ2 and φ4, respectively, that are substantially equal in magnitude but opposite in sign. That is, φ1 is approximately equal to -φ3, and φ2 is approximately equal to -φ4.

[0203] Still reference Fig.10In the illustrated embodiment, the waveguide assembly 1012 is configured to couple out non-polarized light that has been totally internally reflected. In this configuration, the display device 1000 additionally includes a linear polarizer 1005 between the waveguide assembly 1012 and the BLA 1008, which is configured to reduce or eliminate, for example, reflect or absorb light having a polarization state that does not result in lens action of the BLA 1008. For example, in an arrangement where the light 1009 coupled out of the waveguide assembly 1012 or the unaffected light 1020 transmitted through the FLA 1004 is not linearly polarized, for example, non-LVP, the linear polarizer 1005 is used to polarize the transmitted light to feed the incident light 820 into the BLA 1008.

[0204] As configured, the BLA 1008 is used to provide variable refractive power (φ1, φ2, and φ1+φ2) to form images at multiple depth planes for the virtual image emitted from the waveguide assembly 1012 toward the user's eye. Although the BLA 1008 provides the virtual image by focusing the image from the waveguide assembly 1012 at multiple depth planes, the world image may be distorted by the BLA 1008. The FLA 1004 is used to compensate for the distortion of the world image caused by the BLA 1008 by providing variable refractive power (φ3=-φ1, φ4=-φ2, and φ3+φ4=-(φ1+φ2)) so that the world image is presented to the user's eye without significant distortion.

[0205] In various embodiments, for example, when deactivated, each of the FLA 1004 and BLA 1008 can provide a net power (positive or negative) within the following range: approximately ±5.0 diopters to 0 diopters; ±4.0 diopters to 0 diopters; ±3.0 diopters to 0 diopters; ±2.0 diopters to 0 diopters; ±1.0 diopters to 0 diopters; including any range defined by any of these values, such as ±1.5 diopters. In some embodiments, the FLA 1004 between the waveguide assembly 1012 and the world can have a positive refractive power, while the BLA 1008 between the waveguide assembly 1012 and the user can have a negative refractive power, so that the refractive powers of the FLA 1004 and BLA 1008 compensate for each other when viewing the world.

[0206] As described above, as the image of the virtual object generated by the light coupled out of the waveguide assembly 1012 moves in 3D, the net refractive power of the BLA 1008 on the user side is adjusted to adapt to the changing depth of the virtual depth plane. At the same time, according to an embodiment, the net refractive power of the FLA 1004 is adjusted accordingly using a switching circuit so that the view of the real world does not become undesirably defocused or distorted. To address this and other needs, in some embodiments, the display device 100 includes a controller (not shown) that is configured so that when the net refractive power of one of the FLA 1004 and the BLA 1008 is electrically adjusted, the net refractive power of the other of the FLA 1004 and the BLA 1008 is adjusted accordingly so that the combined net refractive power remains approximately constant, for example, approximately zero. The controller circuit and the switchable wave plates are configured such that the time to switch HWPI 804-1, HWP2 804-2, HWP3 804-3, and HWP4 804-4 to adjust the virtual depth plane using the user-side adaptive lens assembly 1008 and to compensate the real world using the user-side adaptive lens assembly 1004 is less than about 100 milliseconds, less than about 50 milliseconds, less than about 10 milliseconds, less than about 5 milliseconds, less than about 1 millisecond, or a value within a range defined by any of these values.

[0207] Display comprising an adaptive lens assembly having a polarization selective lens stack coupled to a polarization waveguide assembly equipment

[0208] Fig.11A An example display device 1100 is shown according to some embodiments. Fig.10 The display device described, the display device 1100 includes a second adaptive lens assembly (BLA) 1008, the second adaptive lens assembly (BLA) 1008 including a first switchable wave plate (HWP1) 804-1, a first polarization selective lens stack (L1) 700-1, a second switchable wave plate (HWP2) 804-2 and a second polarization selective lens stack (L2) 700-2. However, unlike the above with respect to Fig.10 The display device described, the display device 1100 includes a polarization waveguide component 1112, which couples polarized light 1108, for example, circularly polarized light, out to the BLA 1008. Therefore, the BLA 1008 additionally includes a first quarter wave plate (QWP1) 1104, for example, an achromatic quarter wave plate, which is configured to convert the RHCP light 1108-R and the LHCP light 1108-L coupled out from the polarization waveguide component 1112 into linearly polarized light 820 incident on the BLA 1008. Therefore, the BLA 1008 is as described above with respect to Fig.10 The method described above operates in a similar manner.

[0209] However, unlike Fig.10 The display device 1000 does not have a FLA 1004 that is configured to compensate or cancel the undesired refractive power applied by the BLA 1008 to the world-side light 1020 when the BLA 1008 applies refractive power to the light containing virtual image information from the polarization waveguide assembly 1112. Instead, the display device 1100 is configured to alternately display the world image and the virtual image. This is achieved by replacing the FLA 1004 ( QWP2 ) with a combination of a shutter 1120, a linear polarizer 1116, and a second quarter wave plate (QWP2) 1114, such as an achromatic quarter wave plate. Fig.10 ) is realized. In the following, the polarization waveguide component 1112 is relative to Fig. 11B Describe, followed by relative Fig. 11C and Fig.11D The operating principle of the display device 1100 is shown.

[0210] Fig. 11B An example of a polarization waveguide component 1112 according to an embodiment is shown. In some embodiments, the polarization waveguide component 1112 is configured to output circularly polarized light, for example, right-hand (RHCP) or left-hand (LHCP) circularly polarized light. In various embodiments, the polarization waveguide component 1112 may include a cholesteric liquid crystal (CLC) layer and / or a CLC grating (CLCG), which in turn includes liquid crystals arranged to have multiple chiral structures. Each of the chiral structures includes a plurality of liquid crystal molecules extending at least one pitch in the layer depth direction and rotating continuously in the rotation direction. The CLC layer or CLCG may be advantageously configured to substantially Bragg reflect elliptical or circularly polarized light having a polarization chirality matching the rotation direction of the liquid crystal molecules, while being configured to substantially transmit elliptical or circularly polarized light having a polarization chirality opposite to the rotation direction of the liquid crystal molecules. Based on these characteristics of the CLC layer and the CLCG, various embodiments of the display device disclosed herein have a polarization waveguide component 1112 including one or more CLC layers or CLCGs. According to an embodiment, the polarization waveguide assembly 1112 may include a CLCG 1150 configured to couple out an optical element such as an exit pupil (EPE). The polarization waveguide assembly 1112 includes a waveguide 1104 coupled to the CLCG 1150 and configured to propagate light by total internal reflection (TIR).

[0211] Still reference Fig. 11B, the liquid crystal molecules of the CLCG 1150 shown are continuously rotated in the rotation direction, and the arrangement of the liquid crystal molecules of the chiral structure periodically changes in the lateral direction (x, y directions) perpendicular to the layer depth direction (z direction). Due to the rotational arrangement of the liquid crystal molecules, when the light 2604 is elliptically / circularly polarized light having a polarization chirality, for example, one of left chirality or right chirality, which matches the rotation direction of the liquid crystal molecules of the chiral structure, the light 2604 is Bragg reflected by the CLCG 1150. That is, the rotational arrangement of the liquid crystal molecules in the CLCG 1150 causes the CLCG 1150 to selectively Bragg reflect light having one chirality, while non-Bragg reflecting or transmitting light having the opposite chirality. In addition, since the Bragg reflection occurs under diffraction conditions, the Bragg reflected light 1108 is unidirectional (for example, most of the light is directed in one direction when outcoupled, such as by Fig. 11B 1108 in the direction indicated by the arrow 1108 in FIG. 1100 ). The outcoupled light can maintain a uniform polarization state corresponding to the chirality of the CLC material. Therefore, when configured as an optical outcoupling element, the CLCG 1150 acts as a polarizer and a one-way reflector, which allows for efficient integration with other optical components within the display device 1100.

[0212] As described above, the display device 1100 is configured to alternately display the world image ( Fig. 11C ) and virtual images ( Fig.11D ). refer to Fig. 11C , when displaying the world image, the display device 1100 has a configuration 1100C in which both the shutter 1120 and the waveguide assembly 1112 are in the off state. In addition, both the HWP-1 820-1 and the HWP-2 820-2 are in the on state and the off state, respectively. As configured, the BLA 1008 is similarly configured as described above with respect to Fig. 9B State 900B described. In this configuration, unpolarized light 1020 from the world is transmitted through the substantially unaffected shutter 1120 and is linearly polarized, e.g., horizontal linear polarization (LHP), by the linear polarizer 1116 as light 1124. Light 1124 is converted to circularly polarized light 1108-L, e.g., LHCP light, which is incident on the polarization waveguide component 1112. Light 1108-L passes through the polarization waveguide component 1112 in the substantially unaffected off state and is converted by QWP1 1104 to linearly polarized linearly polarized light 820-2, e.g., LHP. As described above with respect to Fig. 9B Similar to the described state, BLA 1008 is configured to exert substantially zero optical power, thereby passing light 820-2 substantially unaffected to be seen by the eye.

[0213] refer to Fig.11D, when displaying a virtual image, the display device has a configuration 1100D in which both the shutter 1120 and the waveguide assembly 1112 are in an on state. Thus, any light 1020 from the world side is blocked, e.g., reflected. Thus, the display device configuration 1100D is configured to display substantially only the light from above relative to the world side. Fig. 11B The described polarization waveguide assembly 1112 couples out virtual content. Light 1108-R having circular polarization, for example, RHCP, is incident on QWP2 1104, and BLA 1008 is similarly configured as described above with respect to FIG. 9C to FIG. 9E In this configuration, the circularly polarized light 1108-R is transformed by QWP2 1104 into linearly polarized light having a polarization direction, for example, a vertical polarization direction (LVP). BLA 1008 then performs the following steps according to the above description with respect to FIG. 9C to FIG. 9E One of the depicted states 900C-900E applies optical power.

[0214] As described, the display device 1100 is configured to sequentially display the world image and the virtual image. In order to display both the world image and the virtual image to the user as if they were presented simultaneously, the configuration 1100C ( Fig. 11C ) and 1100D( Fig.11D ) are time multiplexed relative to each other at a suitable frequency so that the human eye perceives them as being substantially simultaneous. For example, the shutter 1120 and HWP-1 820-1 and HWP-2 820-2 are alternated at a frequency as fast as at least twice the video refresh rate to minimize any switching artifacts. Advantageously, the display device 1100 can reduce the total number of optical elements by replacing the FLA 1008 in the display device 1000. To compensate for the reduction in the intensity of the virtual image due to multiplexing and polarization, the intensity of the outcoupled light 1108-R can be adjusted accordingly according to the embodiment.

[0215] Display device including world-side and / or user-side shutter elements and a user-side lens assembly

[0216] Fig. 12AAn example of a display device 1200 having a single adaptive lens assembly 1208 on the user side of the eyepiece 1212 (the side of the eyepiece 1212 closest to the user's eye) is shown in accordance with some embodiments of the present disclosure. The lens assembly 1208 may include a variable focus element (VFE) assembly and may be configured to apply positive, negative, or zero refractive power to light passing through it. The display device 1200 may include: one or more world-side shutter elements 1204 coupled to the world side of the eyepiece 1212 (the side of the eyepiece 1212 farthest from the user's eye and closest to world objects); and one or more user-side shutter eyepieces 1202 coupled to the user side of the eyepiece 1212. By sequentially electrically activating the world-side shutter element 1204 and the user-side shutter element 1202 as described herein, world light 432 can pass through the display device 1200 with zero net refractive power applied by the lens assembly 1208, and virtual image light 423 can pass through the display device 1200 with a non-zero (e.g., negative) net refractive power applied by the lens assembly 1208.

[0217] In the illustrated embodiment, the world-side shutter element 1204 includes a world-side polarizer 1216 and a world-side switchable wave plate 1220. The world-side polarizer 1216 can be positioned closer to the world object 430 so that the world light 432 first passes through the world-side polarizer 1216 before passing through the world-side switchable wave plate 1220. When passing through the world-side polarizer 1216, the world light 432 is linearly polarized along a first axis. Therefore, the world-side polarizer 1216 can include a linear polarizer. After passing through the world-side polarizer 1216, the world light 432 passes through the world-side switchable wave plate 1220. When electrically activated, the world-side switchable wave plate 1220 rotates the polarization of the world light 432 by 90 degrees so that, for example, LVP light is converted to LHP light or LHP light is converted to LVP light. When not electrically activated, the world-side switchable wave plate 1220 leaves the world light 432 substantially unchanged.

[0218] In the illustrated embodiment, the user-side shutter element 1202 includes a user-side polarizer 1214 and a user-side switchable wave plate 1218. The user-side polarizer 1214 can be positioned closer to the eyepiece 1212 and the world object 430 so that the virtual image light 423 and the world light 432 first pass through the user-side polarizer 1214 before passing through the user-side switchable wave plate 1218. When passing through the user-side polarizer 1214, the virtual image light 423 and the world light 432 are linearly polarized along a second axis perpendicular to the first axis. Therefore, the user-side polarizer 1214 may include a linear polarizer perpendicular to the world-side polarizer. After passing through the user-side polarizer 1214, the virtual image light 423 and the world light 432 pass through the first layer of the lens assembly 1208. As described herein, the first layer of the lens assembly 1208 can apply a refractive power to the light passing through it. After passing through the first layer of the lens assembly 1208, the virtual image light 423 and the world light 432 pass through the user-side switchable wave plate 1214. When electrically activated, the user-side switchable wave plate 1214 rotates the polarization of the virtual image light 423 and the world light 432 by 90 degrees, so that, for example, LVP light is converted to LHP light or LHP light is converted to LVP light. When not electrically activated, the user-side switchable wave plate 1214 leaves the virtual image light 423 and the world light 432 substantially unchanged.

[0219] After passing through the user-side switchable wave plate 1218, the virtual image light 423 and the world light 432 pass through the second layer of the lens assembly 1208. As described herein, the second layer of the lens assembly 1208 can apply a refractive power to the light passing through it so as to offset or add to the refractive power applied to the light when passing through the first layer. For example, the first and second layers of the lens assembly 1208 can be configured so that when the user-side switchable wave plate 1218 is electrically activated, the light passing through the two layers is applied with a non-zero net refractive power, and when the user-side switchable wave plate 1218 is not electrically activated, the light passing through the two layers is applied with a zero net refractive power, i.e., no net refractive power is applied. Thus, the first and second layers of the lens assembly 1208 can be configured to apply a positive refractive power to light having a first linear polarization and to apply a negative refractive power (of equal magnitude) to light having a second linear polarization orthogonal to the first linear polarization.

[0220] In some embodiments, the first and second layers of the lens assembly 1208 are diffractive wave plate lenses. In some embodiments, the lens assembly 1208 can take the form of different types of VFEs, such as LC Fresnel lenses, deformable lenses, etc. In some embodiments, one or more components of the user-side shutter element 1202 are considered subcomponents of the lens assembly 1208 (i.e., considered to be included in the lens assembly 1208). In one example, the user-side polarizer 1214 is considered a subcomponent of the lens assembly 1208. In another example, the user-side switchable wave plate 1218 is considered a subcomponent of the lens assembly 1208. In another example, both the user-side polarizer 1214 and the user-side switchable wave plate 1218 are considered subcomponents of the lens assembly 1208. Example VFEs and other adaptive lens components that may represent or be implemented as one or more of the lens assemblies described herein are described in: U.S. Patent Application No. 15 / 902,927, filed on February 22, 2018, published as U.S. Publication No. 2018 / 0239177 on August 23, 2018; U.S. Patent No. 15 / 902,927, filed on February 22, 2018, published as U.S. Publication No. 2018 / 0239147 on August 23, 2018 Application No. 15 / 902,814; U.S. Patent Application No. 15 / 933,297, filed on March 22, 2018, published as U.S. Publication No. 2018 / 0275394 on September 27, 2018; and U.S. Patent Application No. 16 / 006,080, filed on June 12, 2018, published as U.S. Publication No. 2018 / 0356639 on December 13, 2018; the entire contents of which are expressly incorporated herein by reference. Additional examples of such components are found in U.S. Provisional Patent Application No. 62 / 639,882 filed on March 7, 2018 (attorney docket number MLEAP.180PR) and U.S. Patent Application No. 16 / 158,041 filed on October 11, 2018 (attorney docket number MLEAP.183A), both of which are also expressly incorporated herein by reference in their entirety.

[0221] Fig. 12BAn example of a display device 1200 operating according to a first state according to some embodiments of the present disclosure is shown. When operating according to the first state, the projector and injection optical device 1222 are turned off, the world side switchable wave plate 1220 is electrically activated, and the user side switchable wave plate 1218 is not electrically activated. The world light 432 is first linearly polarized along a first axis by the world side polarizer 1216. Thereafter, the polarization of the world light 432 is rotated 90 degrees by the world side switchable wave plate 1220. Thereafter, the world light 432 is linearly polarized along a second axis perpendicular to the first axis by the user side polarizer 1214. Thereafter, the first layer of the lens assembly 1208 applies a first refractive power to the world light 432. Thereafter, the world light 432 passes through the user side switchable wave plate 1218 substantially unchanged. Thereafter, the second layer of the lens assembly 1208 applies a second refractive power to the world light 432 that is equal in magnitude to the first refractive power but opposite in sign, thereby canceling the first refractive power. Thereafter, the world light 432 reaches the user's eyes.

[0222] Fig. 12C An example of a display device 1200 operating according to a second state according to some embodiments of the present disclosure is shown. When operating according to the second state, the projector and injection optics 1222 are turned on, the world-side switchable wave plate 1220 is not electrically activated, and the user-side switchable wave plate 1218 is electrically activated. The world light 432 incident on the world-side polarizer 1216 is linearly polarized along a first axis by the world-side polarizer 1216. Thereafter, the world light 432 passes through the world-side switchable wave plate 1220 substantially unchanged. Thereafter, the world light 432 is linearly polarized along a second axis perpendicular to the first axis by the user-side polarizer 1214, so that the world light 432 is completely or at least partially reduced, blocked, or dimmed. At the same time, the virtual image light 423 is projected onto one or more waveguides of the eyepiece 1212 by the projector and injection optics 1222. Thereafter, the virtual image light 423 is coupled out by the eyepiece 1212. Thereafter, virtual image light 423 is linearly polarized along a second axis by user-side polarizer 1214. Thereafter, a first layer of lens assembly 1208 applies a first refractive power to virtual image light 423. Thereafter, polarization of virtual image light 423 is rotated 90 degrees by user-side switchable wave plate 1218. Thereafter, a second layer of lens assembly 1208 applies a second refractive power of equal magnitude and same sign to virtual image light 423, thereby doubling the applied refractive power. Thereafter, virtual image light 423 reaches the user's eye.

[0223] Fig.13A method 1300 of operating an optical system according to some embodiments of the present disclosure is shown. One or more steps of the method 1300 may be performed in a different order than the illustrated embodiment, and one or more steps of the method 1300 may be omitted during the execution of the method 1300. In some embodiments, one or more steps of the method 1300 may be implemented as a computer-readable medium or a computer program product including instructions that, when the program is executed by one or more computers, causes the one or more computers to at least partially perform some or all of the steps of the method 1300. Such a computer program product may be transmitted in a data carrier signal carrying the computer program product over a wired or wireless network.

[0224] At step 1302, light associated with a world object is received at an optical system. At step 1304, the light associated with the world object is linearly polarized along a first axis. At step 1306, it is determined whether the optical system is operating according to a first state or a second state. When the optical system is operating according to the first state, the method 1300 proceeds to step 1308. When the optical system is operating according to the second state, the method 1300 proceeds to step 1314. At step 1308, the polarization of the light associated with the world object is rotated 90 degrees. At step 1310, the light associated with the world object is linearly polarized along a second axis perpendicular to the first axis. At step 1312, zero net refractive power is applied to the light associated with the world object. Thereafter, the light associated with the world object reaches the eye of the user.

[0225] At step 1314, light associated with the virtual image is projected onto the eyepiece of the optical system. At step 1316, the light associated with the virtual image is coupled out of the eyepiece. At step 1318, the light associated with the world object and the light associated with the virtual image are linearly polarized along a second axis. At step 1320, the polarization of the light associated with the virtual image is rotated 90 degrees. At step 1322, a non-zero net refractive power is applied to the light associated with the virtual image. Thereafter, the light associated with the virtual image reaches the eye of the user.

[0226] Fig.14 A method 1400 of operating an optical system according to some embodiments of the present disclosure is shown. One or more steps of method 1400 may be performed in a different order than the illustrated embodiment, and one or more steps of method 1400 may be omitted during execution of method 1400. One or more steps of method 1400 may be combined with one or more steps of method 1300. At step 1402, ambient light is detected by an ambient light sensor. At step 1404, a shutter frequency is determined based on the detected ambient light. At step 1406, the optical system is switched between operation according to a first state and operation according to a second state based on the shutter frequency.

[0227] Fig.15 An example execution of method 1400 is shown according to some embodiments of the present disclosure. Fig.15 The upper graph of shows the detected ambient light intensity (as detected by, for example, ambient light sensors 434, 534) over time. Fig.15 The lower figure of shows the state switching between the first state and the second state as a function of time, wherein the time is aligned with the upper figure. At time T1, the user of the optical system is in a shaded outdoor area and the detected ambient light has a medium intensity. Based on the ambient light detected at time T1, a first shutter frequency is determined. Determining the shutter frequency may include determining a first period P1, a duration for which the optical system operates according to the first state before switching to the second state, and a second period P2, a duration for which the optical system operates according to the second state before switching to the first state. Alternatively or additionally, determining the shutter frequency may include determining a ratio P1 / P2, among other possibilities. Between times T1 and T2, the optical system is switched between the first state and the second state based on the first shutter frequency.

[0228] At time T2, the user of the optical system relocates to a low-light indoor area, and the detected ambient light has a low intensity. Based on the ambient light detected at time T2, a second shutter frequency having a higher ratio P1 / P2 than the first shutter frequency is determined. In other words, in order to improve the user experience and not excessively dim the world light in low-light conditions, the shutter frequency can be adjusted to increase the amount of time that the world light is allowed to pass through the optical system. Between time T2 and T3, the optical system is switched between the first state and the second state based on the second shutter frequency.

[0229] At time T3, the user of the optical system relocates to an outdoor area with direct sunlight, and the detected ambient light has a high intensity. Based on the ambient light detected at time T3, a third shutter frequency is determined having a lower ratio P1 / P2 than the first and second shutter frequencies. In other words, to improve the user experience and reduce world light under high light conditions, the shutter frequency can be adjusted to reduce the amount of time that world light is allowed to pass through the optical system. After time T3, the optical system is switched between the first state and the second state based on the third shutter frequency.

[0230] Fig.16A An example of a display device 1600 operating according to a first state according to some embodiments of the present disclosure is shown. The display device 1600 may include a display device 1600 that is functionally equivalent or similar to the above referenced device. FIG. 4A to FIG. 4C , Figure 5 , FIG. 11A to FIG. 11D , and / or FIG. 12A to FIG. 12COne or more of the components described. For example, the display device 1600 may have a single adaptive lens assembly 1605 on the user side of the eyepiece 1602 (the side of the eyepiece 1602 closest to the user's eye). The lens assembly 1605 may include a VFE assembly and may be configured to apply positive, negative, or zero refractive power to the light passing through it. The display device 1600 may include a shutter element 1603, which is coupled to the world side of the eyepiece 1602 (the side of the eyepiece 1602 farthest from the user's eye and closest to the world object). When operating according to the first state, the controller 1620 turns off the projector 1614, the lens assembly 1605 is inactive, and the shutter element 1603 is open. When the shutter element 1603 is turned on (i.e., electrically activated), the world light 432 passing through it is substantially unchanged. When the lens assembly 1605 is inactive, the lens assembly 1605 gives zero net refractive power to the light passing through it (e.g., the world light 432). Thus, when operating according to the first state, world light 432 can be presented to the user substantially unchanged. As described in more detail below, in some examples, display device 1600 can maintain / maintain the first state for a long period of time (e.g., indefinitely or until display device 1600 is required to present virtual content to the user).

[0231] Fig. 16B An example of a display device 1600 operating according to a second state according to some embodiments of the present disclosure is shown. When operating according to the second state, the controller 1620 causes the projector 1614 to be turned on, the lens assembly 1605 to be active, and the shutter element 1603 to be closed. When the shutter element 1603 is closed (i.e., not electrically activated), the world light 432 passing through it is substantially blocked. When the projector 1614 is turned on, the virtual image light 423 is projected onto the eyepiece 1602 and thereafter coupled out by the eyepiece 1602 toward the user's eye. When the lens assembly 1605 is active, the lens assembly 1605 imparts a non-zero net refractive power to the light passing through it (e.g., the virtual image light 423). Therefore, when operating according to the second state, the display device 1600 can present to the user virtual content perceived by the user as being positioned at one or more of various possible depths. As described in more detail below, in some examples, display device 1600 can maintain / maintain the second state for a long period of time (e.g., indefinitely or until display device 1600 is required to provide a view of the environment to the user). In some embodiments, display device 1600 can synchronously control shutter element 1603 and lens assembly 1605 to rapidly alternate between the first state and the second state at a particular rate or frequency.

[0232] Fig. 16CAn example of a display device 1600 operating according to a third state according to some embodiments of the present disclosure is shown. When operating according to the third state, the controller 1620 turns on the projector 1614, the lens assembly 1605 is inactive, and the shutter element 1603 is open. When the shutter element 1603 is open (i.e., electrically activated), the world light 432 passing through it is substantially unchanged. When the projector 1614 is turned on, the virtual image light 423 is projected onto the eyepiece 1602 and thereafter coupled out by the eyepiece 1602 toward the user's eye. When the lens assembly 1605 is inactive, the lens assembly 1605 gives zero net refractive power to the light passing through it (e.g., the world light 432 and / or the virtual image light 423). Therefore, when operating according to the third state, the display device 1600 can present virtual content to the user that is perceived by the user as being positioned at optical infinity.

[0233] Thus, in the third state, display device 1600 does not need to activate lens assembly 1605 while injecting light representing virtual content at optical infinity into eyepiece 1602, and can therefore allow light from the real world to pass toward the user without any problems. As described in more detail below, in some examples, display device 1600 can maintain / maintain the third state for a long time (e.g., indefinitely or until display device 1600 is required to present virtual content at less than optical infinity). In some embodiments, display device 1600 can synchronously control shutter element 1603 and lens assembly 1605 to rapidly alternate between the second state and the third state in order to rapidly present some virtual content at less than optical infinity and other virtual content at optical infinity. Similar to reference Fig.14 and Fig.15 As described, the shutter frequency of switching between the first state, the second state, and / or the third state may be determined based on the detected ambient light and / or the desired brightness of the virtual content.

[0234] As mentioned above, in some embodiments, the display device 1600 may not synchronously control the shutter element 1603 and the lens assembly 1605 to rapidly alternate between two or more states, but instead may selectively hold / maintain a single state (e.g., one of the first state, the second state, and the third state) or otherwise independently control the shutter element 1603 and the lens assembly 1605 for a long period of time. In at least some of these embodiments, the display device 1600 may be configured to alternate between at least two different operating modes, the at least two different operating modes including: (i) a first operating mode in which the display device 1600 is configured to independently or otherwise asynchronously control the state of the shutter element 1603 and the state of the lens assembly 1605, and (ii) a second operating mode in which the display device 1600 is configured to synchronously control the state of the shutter element 1603 and the state of the lens assembly 1605. For example, in a first operating mode, the display device 1600 can maintain / maintain a single state (e.g., one of the first state, the second state, and the third state) or otherwise independently control the shutter element 1603 and the lens assembly 1605, and in a second operating mode, the display device 1600 can cause the shutter element 1603 and the lens assembly 1605 to synchronously switch between two or more states (two or more of the first state, the second state, and the third state).

[0235] In some examples, in the first operating mode, the display device 1600 may maintain / maintain a state similar to / equal to the second state for a long period of time (e.g., indefinitely or until the display device 1600 is required to provide a view of the environment to the user). In at least some such examples, the first operating mode may correspond to a VR mode in which the controller 1620 turns on the projector 1614, the lens assembly 1605 is optionally active, and the shutter element 1603 is closed or otherwise maintained in a relatively dim state. Optionally, in the first operating mode, the controller 1620 may cause the lens assembly 1605 to switch states as needed to give the light from the projector an appropriate refractive power. In the foregoing examples, the controller 1620 may cause the display device 1600 to switch to and / or out of the first operating mode based on any of a variety of factors, including user input (e.g., as indicated by data received from one or more sensors, user interfaces, input devices, etc.), applications running on the display device 1600, user preferences, sensor data, etc. For example, the controller 1620 may switch to a first operating mode in order to initiate a VR experience in which the user is provided with almost no see-through visibility of the environment in front of them in response to launching or terminating execution of a specific application on the display device 1600, receiving an indication that the user wishes to enter such a mode or exit another mode based on input received through a handheld controller and / or a graphical user interface, and / or the occurrence of one or more other events. Similarly, the controller 1620 may switch out of the first operating mode in order to terminate the VR experience or transition to an AR or mixed reality (MR) experience in which the user is provided with increased see-through visibility of the environment in front of them in response to launching or terminating execution of a specific application on the display device 1600, receiving an indication that the user wishes to exit the VR mode or enter another mode (e.g., an AR or MR mode) based on input received through a handheld controller and / or a graphical user interface, and / or the occurrence of one or more other events. Other configurations are possible.

[0236] In other examples, in the first operating mode, the display device 1600 may maintain / maintain a state similar to / equal to the third state for a long period of time (e.g., indefinitely or until the display device 1600 is required to present virtual content at less than optical infinity). In at least some such examples, the first operating mode may correspond to a mode in which the controller 1602 turns on the projector 1614, the lens assembly 1605 is maintained in a fixed state, and the shutter element 1603 remains open. Optionally, in the first operating mode, the controller 1620 may switch the shutter element 1603 between an open and closed state. In the foregoing examples, the controller 1620 may switch the display device 1600 to and / or out of the first operating mode based on any of various factors, including the depth at which the user's eyes are determined to be looking, the depth in front of the user at which the virtual content will be perceived by the user, the accommodation-convergence mismatch for the virtual content, etc. In some embodiments, controller 1620 may use data from one or more interior-facing cameras (e.g., images of one or both of the user's eyes) to determine the depth at which the user's eyes are fixated, evaluate the determined depth against a set of criteria, and switch into and / or out of the first operating mode based on the results of the evaluation. For example, in these embodiments, controller 1620 may determine whether an accommodation-convergence mismatch for virtual content exceeds one or more predetermined thresholds based at least in part on the depth at which the user's eyes are determined to be fixated, and may switch into and / or out of the first operating mode in response to determining that the accommodation-convergence mismatch for virtual content exceeds the one or more predetermined thresholds. Example systems and techniques for adjusting the wavefront divergence of light representing virtual content for enhancing user perception, comfort, and / or experience that may represent or be implemented as part of one or more of the systems and techniques described herein are described in: U.S. Patent Application No. 15 / 430,277, filed on February 10, 2017, and published as U.S. Publication No. 2017 / 0237974 on August 17, 2017; U.S. Patent Application No. 15 / 469,369, filed on March 24, 2017, and published as U.S. Publication No. 2017 / 0276948 on September 28, 2019; U.S. Patent Application No. 16 / 250,931, filed on January 17, 2019, published as U.S. Publication No. 2019 / 0243448 on August 8, 2019; U.S. Patent Application No. 16 / 353,989, filed on March 14, 2019, published as U.S. Publication No. 2019 / 0311527 on October 10, 2019; and U.S. Patent Application No. 16 / 389,529, filed on April 19, 2019, published as U.S. Publication No. 2019 / 0324276 on October 24, 2019, the entire contents of which are expressly incorporated herein by reference.In some embodiments, one or more of such systems and techniques described in one or more of the aforementioned patent applications may represent or be implemented as part of one or more of the systems and techniques for switching to and / or out of the first operating mode. Other configurations are possible.

[0237] In the second mode of operation, the controller 1620 of the display device 1600 may cause the shutter element 1603 and the lens assembly 1605 to synchronously switch between different states in a manner that produces an inverse relationship between the amount of ambient light from the user's environment that is allowed to pass through it toward the user by the shutter assembly 1603 and the amount of wavefront divergence imparted by the lens assembly 1605 to the light passing through it toward the user. For example, in the second mode of operation, the controller 1620 of the display device 1600 may cause the shutter element 1603 and the lens assembly 1605 to switch between different states, respectively, in a manner similar to or equal to that described above with reference to FIG. Fig.16A and Fig. 16B The first and second states are switched synchronously between the two states, or the shutter element 1603 and the lens assembly 1605 can be switched in a state similar to or equal to that described above. Fig. 16B and Fig. 16C The second and third states are described as switching synchronously between the two states.

[0238] Fig.17 1700 is shown in accordance with an embodiment described herein. Fig.17 The computer system 1700 shown may be incorporated into the devices described herein. Fig.17 A schematic diagram of one embodiment of a computer system 1700 is provided that can perform some or all of the steps of the methods provided by various embodiments. It should be noted that Fig.17 It is intended only to provide a generalized illustration of the various components, any or all of which may be used as appropriate. Fig.17 It is broadly shown how individual system elements may be implemented in a relatively discrete or relatively more integrated manner.

[0239] A computer system 1700 is shown including hardware elements that may be electrically coupled via a bus 1705 or that may otherwise communicate as appropriate. The hardware elements may include: one or more processors 1710, including but not limited to one or more general purpose processors and / or one or more special purpose processors such as digital signal processing chips, graphics acceleration processors, and / or the like; one or more input devices 1715, which may include but are not limited to a mouse, keyboard, camera, and / or the like; and one or more output devices 1720, which may include but are not limited to a display device, a printer, and / or the like.

[0240] The computer system 1700 may also include and / or communicate with one or more non-transitory storage devices 1725, which may include, but are not limited to, local and / or network-accessible repositories, and / or may include, but are not limited to, disk drives; drive arrays; optical storage devices; solid-state storage devices, such as random access memory ("RAM"); and / or read-only memory ("ROM"), which may be programmable, flash-updated, and / or the like. Such storage devices may be configured to implement any suitable data storage, including, but not limited to, various file systems, database structures, and / or the like.

[0241] The computer system 1700 may also include a communication subsystem 1719, which may include but is not limited to a modem, a network card (wireless or wired), an infrared communication device, a wireless communication device, and / or a Bluetooth® device. TM The communication subsystem 1719 may include one or more input and / or output communication interfaces that allow data to be exchanged with a network (such as the network described below, to name just one example), other computer systems, televisions, and / or any other device described herein. Depending on the desired functionality and / or other implementation issues, a portable electronic device or similar device may transmit images and / or other information via the communication subsystem 1719. In other embodiments, a portable electronic device, such as a first electronic device, may be incorporated into the computer system 1700, for example, as an electronic device of the input device 1715. In some embodiments, the computer system 1700 will also include a working memory 1735, which may include a RAM or ROM device, as described above.

[0242] The computer system 1700 may also include software elements shown as currently located within the working memory 1735, including an operating system 1740, device drivers, executable libraries, and / or other code, such as one or more application programs 1745, which may include computer programs provided by various embodiments, and / or may be designed to implement methods, and / or configure systems provided by other embodiments, as described above. By way of example only, one or more programs described with respect to the methods discussed above may be implemented as code and / or instructions executable by a computer and / or a processor within a computer; in one aspect, such code and / or instructions may then be used to configure and / or adapt a general purpose computer or other device to perform one or more operations according to the described methods.

[0243] The set of these instructions and / or codes may be stored on a non-transitory computer-readable storage medium, such as one or more storage devices 1725 described above. In some cases, the storage medium may be contained within a computer system, such as computer system 1700. In other embodiments, the storage medium may be separate from the computer system, for example, a removable medium, such as an optical disk, and / or provided in an installation package, so that the storage medium can be used to program, configure, and / or adapt a general-purpose computer using the instructions / codes stored thereon. These instructions may take the form of executable code that can be executed by computer system 1700 and / or may take the form of source and / or installable code, which is based on compilation and / or installation on computer system 1700, for example, using any of the commonly available compilers, installers, compression / decompression utilities, etc., and then takes the form of executable code.

[0244] It will be apparent to those skilled in the art that a large number of variations can be made depending on specific requirements. For example, custom hardware may also be used, and / or specific elements may be implemented in hardware, software (including portable software, such as applets, etc.), or both. Furthermore, connections to other computing devices, such as network input / output devices, may be employed.

[0245] As mentioned above, in one aspect, some embodiments may use a computer system such as computer system 1700 to perform methods according to various embodiments of the technology. According to one set of embodiments, some or all of the processes of such methods are performed by computer system 1700 in response to processor 1710 executing one or more sequences of one or more instructions, which may be included in operating system 1740 and / or other code, such as application 1745 contained in working memory 1735. Such instructions may be read into working memory 1735 from another computer-readable medium, such as one or more of one or more storage devices 1725. By way of example only, execution of the sequences of instructions contained in working memory 1735 may cause one or more processors 1710 to perform one or more processes of the methods described herein. Additionally or alternatively, portions of the methods described herein may be performed by dedicated hardware.

[0246] As used herein, the terms "machine-readable medium" and "computer-readable medium" refer to any medium that participates in providing data that causes a machine to operate in a particular manner. In an embodiment implemented using computer system 1700, various computer-readable media may be involved in providing instructions / code to (one or more) processors 1710 for execution and / or may be used to store and / or carry such instructions / code. In many implementations, computer-readable media are physical and / or tangible storage media. Such media may take the form of non-volatile media or volatile media. Non-volatile media include, for example, optical and / or magnetic disks, such as one or more storage devices 1725. Volatile media include, but are not limited to, dynamic memory, such as working memory 1735.

[0247] Common forms of physical and / or tangible computer readable media include, for example, floppy disks, diskettes, hard disks, magnetic tape, or any other magnetic medium, CD-ROMs, any other optical medium, punch cards, paper tape, any other physical medium with a pattern of holes, RAM, PROM, EPROM, FLASH-EPROM, any other memory chip or cassette, or any other medium from which a computer can read instructions and / or code.

[0248] Various forms of computer readable media may be involved in carrying one or more sequences of one or more instructions to one or more processors 1710 for execution. By way of example only, the instructions may initially be carried on a magnetic disk and / or optical disk of a remote computer. The remote computer may load the instructions into its dynamic memory and send the instructions as signals over a transmission medium to be received and / or executed by the computer system 1700.

[0249] The communication subsystem 1719 and / or its components will typically receive the signal, and the bus 1705 may then carry the signal and / or the data, instructions, etc. carried by the signal to the working memory 1735, from which the one or more processors 1710 retrieve and execute the instructions. The instructions received by the working memory 1735 may optionally be stored on the non-transitory storage device 1725 before or after execution by the one or more processors 1710.

[0250] The methods, systems and devices discussed above are examples. Various configurations may omit, replace or add various processes or components as appropriate. For example, in alternative configurations, the method may be performed in an order different from the order described, and / or the stages may be added, omitted and / or combined. Moreover, the features described with respect to certain configurations may be combined in various other configurations. Different aspects and elements of the configurations may be combined in a similar manner. Moreover, technology evolves and therefore many of the elements are examples and do not limit the scope of the present disclosure or claims.

[0251] Specific details are given in the description that provides a thorough understanding of exemplary configurations (including embodiments). However, the configuration can be practiced without these specific details. For example, well-known circuits, processes, algorithms, structures and techniques have been shown without unnecessary details to avoid ambiguous configurations. This description only provides example configurations and does not limit the scope, applicability or configuration of the claims. On the contrary, the foregoing description of the configuration will provide an enabling description for implementing the described technology to those skilled in the art. Various changes can be made in the functions and arrangements of the elements without departing from the spirit or scope of the present disclosure.

[0252] Moreover, the configuration may be described as a process depicted as a schematic flow chart or block diagram. Although each operation may be described as a sequential process, many operations can be performed in parallel or concurrently. In addition, the order of the operations may be rearranged. The process may have additional steps not included in the accompanying drawings. Moreover, the example of the method may be implemented by hardware, software, firmware, middleware, microcode, hardware description language, or any combination thereof. When implemented in software, firmware, middleware, or microcode, the program code or code segment that performs the necessary tasks may be stored in a non-transitory computer-readable medium, such as a storage medium. The processor may perform the described tasks.

[0253] Several example configurations have been described, and various modifications, alternative configurations, and equivalents may be used without departing from the spirit of the present disclosure. For example, the above elements may be components of a larger system, wherein other rules may be superior to or otherwise modify the application of the technology. Moreover, several steps may be performed before, during, or after the above elements are considered. Therefore, the above description does not restrict the scope of the claims.

[0254] As used herein and in the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Thus, for example, reference to "a user" includes a plurality of such users and reference to "a processor" includes reference to one or more processors and equivalents thereof known to those skilled in the art, and so forth.

[0255] Furthermore, when used in this specification and in the following claims, the words "comprises," "contains," "includes," are intended to specify the presence of stated features, integers, components, or steps, but do not preclude the presence or addition of one or more other features, integers, components, steps, actions, or combinations.

[0256] It should also be understood that the examples and embodiments described herein are for illustrative purposes only and that various slight modifications or changes thereof will be suggested to those skilled in the art and are to be included within the spirit and purview of the present application and the scope of the appended claims.

Claims

1. An optical system, comprising: a projector configured to emit light; at least one waveguide optically coupled to the projector and configured to receive light from the projector and redirect the light toward a user; a shutter assembly comprising at least one component positioned adjacent to the at least one waveguide, wherein the shutter assembly is selectively switchable between different states in which the shutter assembly is configured to allow different amounts of ambient light from an environment of the user to pass therethrough toward the user, respectively; an adaptive lens assembly positioned between the at least one waveguide and the user, wherein the adaptive lens assembly is selectively switchable between different states in which the adaptive lens assembly is configured to respectively impart different amounts of wavefront divergence to light passing therethrough toward the user; and a control circuit communicatively coupled to the projector, the shutter assembly, and the adaptive lens assembly, wherein the control circuit is configured to cause the shutter assembly and the adaptive lens assembly to synchronously switch between two or more states at a specific rate, the two or more states comprising: a first state in which the shutter assembly is configured to allow a first amount of ambient light from an environment of the user to pass therethrough toward the user, and the adaptive lens assembly is configured to impart a first amount of wavefront divergence to light passing therethrough; and and a second state in which the shutter assembly is configured to allow a second amount of ambient light from the user's environment to pass through it toward the user, and the adaptive lens assembly is configured to impart a second amount of wavefront divergence to light passing through it, wherein the second amount of ambient light is different from the first amount of ambient light and the second amount of wavefront divergence is different from the first amount of wavefront divergence.

2. The optical system according to claim 1, wherein: The second amount of ambient light is less than the first amount of ambient light, and the second amount of wavefront divergence is greater than the first amount of wavefront divergence.

3. The optical system according to claim 1, wherein: The specific rate at which the shutter assembly and the adaptive lens assembly synchronously switch between the two or more states includes a rate greater than or equal to a minimum switching frequency.

4. The optical system according to claim 1, wherein: In the second state, the control circuit is configured to cause the projector to emit light representing virtual content, which will be perceived by the user as being located at a first depth in front of the user, and wherein the control circuit is configured to determine at least one of the second amount of ambient light and the second amount of wavefront divergence based on the first depth in front of the user at which the virtual content will be perceived by the user.

5. The optical system according to claim 1, wherein: The at least one component in the shutter assembly includes at least one component located between the at least one waveguide and the user.

6. The optical system according to claim 1, wherein: The optical system is an augmented reality (AR) device.

7. The optical system according to claim 1, wherein: The at least one waveguide comprises a plurality of waveguides forming an eyepiece of the optical system.

8. A method of operating an optical system, the method comprising: emitting light at a projector; receiving light by at least one waveguide optically coupled to the projector and redirecting the light toward a user; being selectively switched between different states by a shutter assembly, the shutter assembly comprising at least one component positioned adjacent to the at least one waveguide, in which different states the shutter assembly allows different amounts of ambient light from the user's environment to pass therethrough toward the user, respectively; selectively switching between different states by an adaptive lens assembly positioned between the at least one waveguide and the user, wherein the adaptive lens assembly is configured to impart different amounts of wavefront divergence to light passing therethrough toward the user, respectively; as well as The shutter assembly and the adaptive lens assembly are caused to switch synchronously between two or more states at a specific rate by a control circuit, and the two or more states include: a first state in which the shutter assembly is configured to allow a first amount of ambient light from an environment of the user to pass therethrough toward the user, and the adaptive lens assembly is configured to impart a first amount of wavefront divergence to light passing therethrough; and and a second state in which the shutter assembly is configured to allow a second amount of ambient light from the user's environment to pass through it toward the user, and the adaptive lens assembly is configured to impart a second amount of wavefront divergence to light passing through it, wherein the second amount of ambient light is different from the first amount of ambient light and the second amount of wavefront divergence is different from the first amount of wavefront divergence.

9. The method according to claim 8, wherein: The second amount of ambient light is less than the first amount of ambient light, and the second amount of wavefront divergence is greater than the first amount of wavefront divergence.

10. The method according to claim 8, wherein: The specific rate at which the shutter assembly and the adaptive lens assembly synchronously switch between the two or more states includes a rate greater than or equal to a minimum switching frequency.

11. The method according to claim 8, wherein: In the second state, the control circuit causes the projector to emit light representing virtual content, which will be perceived by the user as being located at a first depth in front of the user, and wherein the control circuit determines at least one of the second amount of ambient light and the second amount of wavefront divergence based on the first depth in front of the user at which the virtual content will be perceived by the user.

12. The method according to claim 8, wherein: The at least one component in the shutter assembly includes at least one component located between the at least one waveguide and the user.

13. The method according to claim 8, wherein: The optical system is an augmented reality (AR) device.

14. The method according to claim 8, wherein: The at least one waveguide comprises a plurality of waveguides forming an eyepiece of the optical system.

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