Variable-focus polarization-sensitive diffuse display

Abstract

A zoom display device includes an image source and a display. The image source is configured to project image light. The display includes a first optical diffuser and a second optical diffuser. The display is configured to receive the image light. The first diffuser is configured to diffuse the image light at the first optical diffuser when the image light has a first polarization, and diffuse the image light at the second optical diffuser when the image light is configured to have a second polarization different from the first polarization. A method of displaying an image using the zoom display device is also disclosed.

Description

Technical Field

[0001] The present invention relates generally to display devices, and more particularly to head mounted display devices. Background Art

[0002] Head-mounted display devices (also referred to herein as head-mounted displays) are becoming increasingly popular as a means for providing visual information to users. For example, some head-mounted display devices are used for virtual reality and augmented reality operations.

[0003] When a head-mounted display device is used for AR applications, it may be desirable for the display device to seamlessly transmit ambient light to the user's eyes while projecting one or more images to the user's eyes. Summary of the invention

[0004] Therefore, there is a need for a head mounted display device with adjustable optical power and which can transmit both ambient light and projected image light to the user's eyes. In addition, it may be desirable for a display device to have adjustable optical power to reduce eye fatigue and improve user comfort and satisfaction with such a device.

[0005] Thus, the disclosed display device of the present invention reduces or eliminates the above-mentioned deficiencies and other problems associated with conventional head mounted display devices.

[0006] According to one aspect of the present invention, a display device is provided, which includes an image source and a display. The image source is configured to project image light. The display includes a first optical diffuser and a second optical diffuser. The display is configured to receive the image light, diffuse the image light at the first diffuser when the image light has a first polarization, and diffuse the image light at the second diffuser when the image light has a second polarization different from (e.g., orthogonal to) the first polarization.

[0007] The display can also be configured to:

[0008] When the image light is configured to have a first polarization, outputting a first diffused image light having the first polarization; and

[0009] When the image light is configured to have a second polarization, a second diffused image light having a second polarization is output, wherein

[0010] The first optical diffuser may include a first surface and may be configured to receive the image light at the first surface; and

[0011] The first diffuse image light and the second diffuse image light may each be output from the first surface.

[0012] The display may also include:

[0013] a first optical retarder disposed between the first optical diffuser and the second optical diffuser, wherein:

[0014] Each of the first optical diffuser and the second optical diffuser may be configured as:

[0015] reflectively diffusing light having a first polarization; and

[0016] transmitting light having a second polarization;

[0017] The first optical retarder may be configured to receive image light transmitted through the first optical diffuser; and

[0018] The first optical retarder may be configured as:

[0019] converting the image light from the second polarization to the first polarization such that the image light is diffused by the second optical diffuser as second diffused image light having the first polarization;

[0020] receiving a second diffuse image light; and

[0021] The second diffuse image light is converted from the first polarization to the second polarization such that the second diffuse image light is transmitted by the first optical diffuser.

[0022] The display may further include one or more third optical diffusers disposed between the first optical diffuser and the second optical diffuser.

[0023] The display may also include:

[0024] one or more second optical retarders, each of the one or more second optical retarders corresponds to a corresponding optical diffuser of the one or more third optical diffusers and is disposed between the corresponding optical diffuser and the first optical diffuser, wherein

[0025] Each of the one or more second optical retarders is configured to transmit the image light transmitted through the first optical diffuser toward the second optical diffuser, and transmit the first diffused image light output from the second optical diffuser toward the first optical diffuser.

[0026] The display may further include one or more fourth optical diffusers, wherein the second optical diffuser is disposed between the first optical diffuser and the one or more fourth optical diffusers.

[0027] The display may also include:

[0028] One or more third optical retarders, each of the one or more third optical retarders corresponds to a corresponding optical diffuser of the one or more fourth optical diffusers and is disposed between the corresponding optical diffuser of the one or more fourth optical diffusers and the second optical diffuser.

[0029] The first optical retarder may be an active optical retarder configurable to be in any of a first state and a second state, and wherein:

[0030] In a first state, the first optical retarder may be configured to transmit the image light and convert the image light from the second polarization to the first polarization; and

[0031] In the second state, the first optical retarder may be configured to transmit the image light.

[0032] Image sources can include:

[0033] a projector configured to output image light having an initial polarization;

[0034] a second switchable optical retarder configured to receive image light having an initial polarization and configurable to be in a first state or a second state, wherein

[0035] When the second switchable optical retarder is in the first state, image light output from the image source may be configured to have a first polarization; and

[0036] When the second switchable optical retarder is in the second state, the image light output from the image source may be configured to have a second polarization; and

[0037] Polarization sensitive optical element, configured as:

[0038] When the image light is configured to have a first polarization, projecting the image light in a first direction toward a first optical diffuser; and

[0039] When the image light is configured to have a second polarization, projecting the image light in a second direction toward a second optical diffuser,

[0040] Wherein a second switchable optical delay device is arranged between the projector and the polarization-sensitive optical element.

[0041] The first optical diffuser and the second optical diffuser may have the same optical axis; and

[0042] The image source may be located off-axis relative to the optical axis.

[0043] The first optical diffuser may be spaced apart from the second optical diffuser.

[0044] Each of the first optical diffuser and the second optical diffuser may be configured to diffuse first light having a first polarization and transmit second light having a second polarization.

[0045] The display device may also include:

[0046] a first switchable optical retarder configured to receive any diffuse image light of the first diffuse image light and the second diffuse image light and output a third diffuse image light, wherein:

[0047] The first switchable optical retarder may be configurable to be in a third state when the image light has the first polarization, or in a fourth state when the image light has the second polarization; and

[0048] The third diffused image light has a third polarization regardless of whether the first switchable optical retarder is in the third state or the fourth state; and

[0049] The lens assembly is configured to:

[0050] receiving a third diffuse image light output from the first switchable optical retarder and focusing the third diffuse image light at a first optical power; and

[0051] Light having a fourth polarization different from the third polarization is transmitted at a second optical power, the second optical power different from the first optical power, wherein a first switchable optical retarder is disposed between the display and the lens assembly.

[0052] The display may be configured to transmit a portion of ambient light incident on the display; and

[0053] The lens assembly may be configured to transmit a portion of the ambient light at a second optical power.

[0054] Each of the first optical diffuser and the second optical diffuser may include a polarization-sensitive hologram.

[0055] The respective optical diffusers of the first optical diffuser and the second optical diffuser may include:

[0056] a first optical surface;

[0057] a second optical surface, opposite to the first optical surface; and

[0058] Optically anisotropic molecules are disposed between the first optical surface and the second optical surface and are arranged such that the corresponding optical diffuser is configured as:

[0059] diffusing first light having a first polarization; and

[0060] A second light having a second polarization is transmitted.

[0061] The first light may include third light within the first wavelength range and fourth light within the second wavelength range; and

[0062] The respective optical diffusers of the first optical diffuser and the second optical diffuser may include:

[0063] a first optical surface;

[0064] a second optical surface;

[0065] a third optical surface;

[0066] first optically anisotropic molecules arranged to diffuse the third light and disposed between the first optical surface and the second optical surface; and

[0067] The second optically anisotropic molecules are arranged to diffuse the fourth light and are disposed between the second optical surface and the third optical surface.

[0068] The first light may include fifth light within a first incident angle range and sixth light within a second incident angle range; and

[0069] The respective optical diffusers of the first optical diffuser and the second optical diffuser may include:

[0070] a first optical surface;

[0071] a second optical surface;

[0072] a third optical surface;

[0073] first optically anisotropic molecules arranged to diffuse fifth light and disposed between the first optical surface and the second optical surface; and

[0074] The second optically anisotropic molecules are arranged to diffuse the sixth light and are disposed between the second optical surface and the third optical surface.

[0075] According to another aspect of the present invention, a display device is provided, the display device including an image source configured to project image light. The image light may be configured to have a first circular polarization or a second circular polarization different from (e.g., orthogonal to) the first polarization. The display also includes a display having a first optical diffuser and a second optical diffuser. The display is configured to receive the image light, diffuse the image light at the first diffuser when the image light is configured to have the first polarization, and diffuse the image light at the second diffuser when the image light is configured to have the second polarization.

[0076] According to another aspect of the present invention, a method for displaying an image is provided, the method comprising: providing image light from an image source, and receiving the image light at a first optical diffuser. The method further comprises: when the image light received at the first optical diffuser has a first polarization, diffusing the image light at the first optical diffuser to output a first diffused image light having the first polarization. The method further comprises: when the image light received at the first optical diffuser has a second polarization different from the first polarization: (i) transmitting the image light through the first optical diffuser, (ii) converting the image light from the second polarization to the first polarization, (iii) diffusing the image light having the first polarization at the second optical diffuser to output a second diffused image light having the first polarization, (iv) converting the second diffused image light from the first polarization to the second polarization, and (v) transmitting the second diffused image light having the second polarization through the first optical diffuser.

[0077] Each of the first optical diffuser and the second optical diffuser may be configured to diffuse light having a first polarization and transmit light having a second polarization.

[0078] According to another aspect of the present invention, there is provided a method for displaying an image, the method comprising projecting a first image light having a first circular polarization. The method further comprises diffusing the first image light at a first optical diffuser to output a first diffused image light, the first diffused image light having a first polarization. The method further comprises projecting a second image light having a second circular polarization different from (e.g., orthogonal to) the first polarization, transmitting the second image light through the first optical diffuser, and converting the second image light into a third image light having the first polarization. The method further comprises diffusing a third image light at a second optical diffuser to output a second diffused image light, the second diffused image light having the first polarization, converting the second diffused image light into a third diffused image light having a second polarization, and transmitting the third diffused image light through the first optical diffuser.

[0079] It will be appreciated that any feature discussed as suitable for inclusion in any aspect described herein will also be suitable for inclusion in any other aspect, in any combination.

[0080] Thus, the disclosed embodiments provide a variable focus polarization selective diffusion display having adjustable optical power and capable of diffusing image light having a first polarization and transmitting ambient light having a polarization different from the first polarization without diffusing the ambient light or adding significant aberrations or distortions. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] For a better understanding of the various embodiments described, reference should be made to the following "Detailed Description" in conjunction with the following drawings, wherein like reference numerals represent corresponding parts throughout the several views.

[0082] Figure 1 is a perspective view of a display device according to some embodiments.

[0083] Figure 2 is a block diagram of a system including a display device according to some embodiments.

[0084] Figure 3 is an isometric view of a display device according to some embodiments.

[0085] Figures 4A-4F is a schematic diagram illustrating a display device according to some embodiments.

[0086] Figure 4G-4H is a schematic diagram illustrating the operation of a switchable optical retarder in a display device according to some embodiments.

[0087] Figure 4I-4K is a schematic diagram illustrating the optical path of light in an optical lens assembly of a display device according to some embodiments.

[0088] Figure 4L-4M is a schematic diagram illustrating a projector in a display device according to some embodiments.

[0089] Figure 4N-4P The operation of a display device according to some embodiments is shown.

[0090] Figures 5A-5D is a cross-sectional view of a polarization-sensitive hologram according to some embodiments.

[0091] Figure 6 is a schematic diagram illustrating a polarization-sensitive hologram according to some embodiments.

[0092] Figure 7 is a flow chart of a method of displaying an image according to some embodiments.

[0093] Unless otherwise noted, the figures are not drawn to scale. DETAILED DESCRIPTION

[0094] The present invention provides a head-mounted display device (or display device) that projects diffuse image light having a first polarization to a user and transmits ambient light having a second polarization to the user without diffusing the ambient light. In addition, the head-mounted display device has adjustable optical power that reduces eye fatigue or user discomfort associated with vergence accommodation conflict. In some embodiments, the ambient light is transmitted to the viewer without significant optical aberrations or distortions to allow a user of the display device to accurately perceive and interact with objects in the external environment.

[0095] Reference will now be made to embodiments, examples of which are illustrated in the accompanying drawings. In the following description, many specific details are set forth to provide an understanding of the various embodiments described. However, it is clear to one of ordinary skill in the art that the various embodiments described may be practiced without these specific details. In other cases, well-known methods, processes, components, circuits, and networks are not described in detail to avoid unnecessarily obscuring aspects of the embodiments.

[0096] It should also be understood that although the terms first, second, etc. are used in some cases herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, without departing from the scope of the various embodiments described, a first light projector may be referred to as a second light projector, and similarly, a second light projector may be referred to as a first light projector. Both the first light projector and the second light projector are light projectors, but they are not the same light projector.

[0097] The terms used in the description of the various embodiments described herein are only used for the purpose of describing specific embodiments and are not intended to be limiting. As used in the description of the various embodiments described and the appended claims, the singular forms "a", "an" and "the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. It will be further understood that when used in this specification, the terms "includes", "including", "comprises" and / or "comprising" specify the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups thereof. The term "exemplary" used herein means "used as an example, instance or illustration", rather than "representing the best of its kind".

[0098] Figure 1 1 shows a perspective view of a display device 100 according to some embodiments. In some embodiments, the display device 100 is configured to be worn on the user's head (e.g., by having a Figure 1When the display device 100 is configured to be worn on the head of a user, the display device 100 is referred to as a head-mounted display. Alternatively, the display device 100 is configured for placement near one or more eyes of the user in a fixed position, rather than being head-mounted (e.g., the display device 100 is mounted in a vehicle such as a car or airplane for placement in front of one or more eyes of the user). Figure 1 As shown, the display device 100 includes a display 110. The display 110 is configured to present visual content (eg, augmented reality content, virtual reality content, mixed reality content, or any combination thereof) to a user.

[0099] In some embodiments, the display device 100 includes the Figure 2 In some embodiments, the display device 100 includes Figure 2 Additional components not shown.

[0100] Figure 2 is a block diagram of a system 200 according to some embodiments. Figure 2 The system 200 shown includes a display device 205 (which corresponds to Figure 1 ), an imaging device 235, and an input interface 240, each of which is coupled to the console 210. Figure 2 An example of a system 200 including a display device 205, an imaging device 235, and an input interface 240 is shown, but in other embodiments, any number of these components may be included in the system 200. For example, there may be multiple display devices 205, each display device 205 having an associated input interface 240 and monitored by one or more imaging devices 235, each display device 205, input interface 240, and imaging device 235 communicating with the console 210. In alternative configurations, different and / or additional components may be included in the system 200. For example, in some embodiments, the console 210 is connected to the system 200 via a network (e.g., the Internet) or is self-contained as part of the display device 205 (e.g., physically located inside the display device 205). In some embodiments, the display device 205 is used to create a mixed reality by adding a view of a real environment. Therefore, the display device 205 and system 200 described herein can achieve augmented reality, virtual reality, and mixed reality.

[0101] In some embodiments, Figure 1As shown, display device 205 is a head mounted display that presents media to the user. Examples of media presented by display device 205 include one or more images, videos, audio, or some combination thereof. In some embodiments, audio is presented via an external device (e.g., speaker and / or earphones), which receives audio information from display device 205, console 210, or both and presents audio data based on the audio information. In some embodiments, display device 205 immerses the user in an augmented environment.

[0102] In some embodiments, the display device 205 is also used as an augmented reality (AR) headset. In these embodiments, the display device 205 uses computer-generated elements (e.g., images, videos, sounds, etc.) to enhance the view of the physical real world environment. In addition, in some embodiments, the display device 205 can cycle between different types of operations. Therefore, based on instructions from the application engine 255, the display device 205 operates as a virtual reality (VR) device, an augmented reality (AR) device, glasses, or some combination thereof (e.g., glasses without optical correction, glasses with optical correction for the user, sunglasses, or some combination thereof).

[0103] The display device 205 includes an electronic display 215, one or more processors 216, an eye tracking module 217, an adjustment module 218, one or more positioners 220, one or more position sensors 225, one or more position cameras 222, a memory 228, an inertial measurement unit (IMU) 230, one or more optical components 260, or a subset or superset thereof (e.g., a display device 205 having an electronic display 215, an optical component 260, and no other listed components). Some embodiments of the display device 205 have modules different from those described herein. Similarly, functionality may be distributed between modules in a manner different from that described herein.

[0104] One or more processors 216 (e.g., processing units or cores) execute instructions stored in memory 228. Memory 228 includes high-speed random access memory, such as DRAM, SRAM, DDR RAM, or other random access solid-state memory devices; and may include non-volatile memory, such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid-state storage devices. Memory 228, or alternatively (multiple) non-volatile memory devices within memory 228, includes non-transitory computer-readable storage media. In some embodiments, memory 228 or a computer-readable storage medium of memory 228 stores programs, modules, and data structures and / or instructions for displaying one or more images on electronic display 215.

[0105] The electronic display 215 displays images to the user based on data received from the console 210 and / or the processor(s) 216. In various embodiments, the electronic display 215 may include a single adjustable display element or multiple adjustable display elements (e.g., one display for each eye of the user). In some embodiments, the electronic display 215 is configured to project images to the user through one or more optical components 260.

[0106] In some embodiments, the display element includes one or more light-emitting devices and a corresponding array of spatial light modulators. The spatial light modulator is an array of electro-optical pixels, an array of photoelectric pixels, an array of some other devices that dynamically adjusts the amount of light transmitted by each device, or some combination thereof. These pixels are located behind one or more lenses. In some embodiments, the spatial light modulator is a liquid crystal-based pixel array in an LCD (liquid crystal display). Examples of light-emitting devices include: organic light-emitting diodes, active matrix organic light-emitting diodes, light-emitting diodes, some type of device that can be placed in a flexible display, or some combination thereof. The light-emitting device includes a device that can generate visible light (e.g., red, green, blue, etc.) for image generation. The spatial light modulator is configured to selectively attenuate individual light-emitting devices, groups of light-emitting devices, or some combination thereof. Alternatively, when the light-emitting device is configured to selectively attenuate individual light-emitting devices and / or groups of light-emitting devices, the display element includes an array of such light-emitting devices without a separate emission intensity array.

[0107] One or more optical components of one or more optical assemblies 260 direct light from the array of light emitters (optionally via an emission intensity array) to locations within each eyebox. Figure 3 The eyebox 380 shown in FIG. 1 is the area occupied by the eyes of a user of display device 205 (e.g., a user wearing display device 205) who is viewing an image from display device 205. In some embodiments, the eyebox is represented as a 10 mm x 10 mm square. In some embodiments, one or more optical components include one or more coatings, such as an anti-reflective coating.

[0108] In some embodiments, the display element includes an infrared (IR) detector array that detects infrared light reflected from the viewing user's retina, from the surface of the cornea, from the lens of the eye, or from some combination thereof. The IR detector array includes an IR sensor or multiple IR sensors, each IR sensor corresponding to a different position of the pupil of the viewing user's eye. In alternative embodiments, other eye tracking systems may also be employed.

[0109] Eye tracking module 217 determines the location of each pupil of the user's eyes. In some embodiments, eye tracking module 217 instructs electronic display 215 to illuminate the eye movement area with IR light (eg, via an IR emitting device in a display element).

[0110] A portion of the emitted IR light will pass through the pupil of the viewing user and reflect back from the retina toward the IR detector array, which is used to determine the location of the pupil. Alternatively, reflections from the surface of the eye are also used to determine the location of the pupil. The IR detector array scans the reflections and identifies which IR emitting devices are active when the reflections are detected. The eye tracking module 217 can use the tracking lookup table and the identified IR emitting devices to determine the pupil location of each eye. The tracking lookup table maps the received signals on the IR detector array to the location in each eye movement range (corresponding to the pupil location). In some embodiments, the tracking lookup table is generated via a calibration process (e.g., the user views various known reference points in the image, and the eye tracking module 217 maps the location of the user's pupil when viewing the reference points to the corresponding signal received on the IR tracking array). As described above, in some embodiments, the system 200 can use other eye tracking systems other than the embedded IR described herein.

[0111] The adjustment module 218 generates an image frame based on the determined pupil location. In some embodiments, this sends a discrete image to a display that tiles the sub-images together so that a coherent stitched image appears on the back of the retina. The adjustment module 218 adjusts the output of the electronic display 215 (i.e., the generated image frame) based on the detected pupil location. The adjustment module 218 instructs portions of the electronic display 215 to pass image light to the determined location of the pupil. In some embodiments, the adjustment module 218 also instructs the electronic display not to pass image light to locations other than the determined pupil location. For example, the adjustment module 218 can block and / or stop light emitting devices whose image light falls outside the determined pupil location, allow other light emitting devices to emit image light that falls within the determined pupil location, translate and / or rotate one or more display elements, dynamically adjust the curvature and / or refractive power of one or more active lenses in a lens (e.g., microlens) array, or some combination thereof.

[0112] The optional locators 220 are objects that are located in specific locations on the display device 205 relative to each other and relative to specific reference points on the display device 205. The locators 220 can be light emitting diodes (LEDs), corner cube reflectors, reflective markers, a type of light source that contrasts with the environment in which the display device 205 operates, or some combination thereof. In embodiments where the locators 220 are active (i.e., LEDs or other types of light emitting devices), the locators 220 can emit light in the visible band (e.g., about 400 nm to 750 nm), in the infrared band (e.g., about 750 nm to 1 mm), in the ultraviolet band (about 100 nm to 400 nm), some other portion of the electromagnetic spectrum, or some combination thereof.

[0113] In some embodiments, the locator 220 is located below an outer surface of the display device 205 that is transparent to the wavelength of light emitted or reflected by the locator 220 or thin enough to not substantially attenuate the light emitted or reflected by the locator 220. Additionally, in some embodiments, the outer surface or other portion of the display device 205 is opaque in the visible band of light wavelengths. Thus, the locator 220 may emit light in the IR band below an outer surface that is transparent in the IR band but opaque in the visible band.

[0114] IMU 230 is an electronic device that generates calibration data based on measurement signals received from one or more position sensors 225. Position sensor 225 generates one or more measurement signals in response to the movement of display device 205. Examples of position sensor 225 include: one or more accelerometers, one or more gyroscopes, one or more magnetometers, another suitable type of sensor that detects movement, a type of sensor used for IMU 230 error correction, or some combination thereof. Position sensor 225 can be located outside IMU 230, inside IMU 230, or some combination thereof.

[0115] Based on one or more measurement signals from one or more position sensors 225, the IMU 230 generates first calibration data indicating an estimated position of the display device 205 relative to an initial position of the display device 205. For example, the position sensor 225 includes a plurality of accelerometers for measuring translational motion (forward / backward, up / down, left / right) and a plurality of gyroscopes for measuring rotational motion (e.g., pitch, yaw, roll). In some embodiments, the IMU 230 samples the measurement signals quickly and calculates an estimated position of the display device 205 based on the sampled data. For example, the IMU 230 integrates the measurement signals received from the accelerometers over time to estimate a velocity vector, and integrates the velocity vector over time to determine an estimated position of a reference point on the display device 205. Alternatively, the IMU 230 provides the sampled measurement signals to the console 210, and the console 210 determines the first calibration data. The reference point is a point that can be used to describe the position of the display device 205. Although a reference point may generally be defined as a point in space; however, in practice, the reference point is defined as a point within the display device 205 (eg, the center of the IMU 230).

[0116] In some embodiments, the IMU 230 receives one or more calibration parameters from the console 210. As discussed further below, the one or more calibration parameters are used to maintain tracking of the display device 205. Based on the received calibration parameters, the IMU 230 can adjust one or more IMU parameters (e.g., sampling rate). In some embodiments, certain calibration parameters cause the IMU 230 to update the initial position of the reference point so that it corresponds to the next calibration position of the reference point. Updating the initial position of the reference point to the next calibration position of the reference point helps to reduce the cumulative error associated with the determined estimated position. The cumulative error (also called drift error) causes the estimated position of the reference point to "drift" away from the actual position of the reference point over time.

[0117] The imaging device 235 generates calibration data based on the calibration parameters received from the console 210. The calibration data includes one or more images showing the viewing position of the locator 220 detectable by the imaging device 235. In some embodiments, the imaging device 235 includes one or more still cameras, one or more video cameras, any other device capable of capturing images (including one or more locators 220), or some combination thereof. In addition, the imaging device 235 may include one or more filters (e.g., for increasing the signal-to-noise ratio). The imaging device 235 is configured to optionally detect light emitted or reflected from the locator 220 in the field of view of the imaging device 235. In embodiments where the locator 220 includes a passive element (e.g., a retroreflector), the imaging device 235 may include a light source that illuminates some or all of the locator 220, and the locator 220 retroreflects light toward the light source in the imaging device 235. The second calibration data is transmitted from the imaging device 235 to the console 210, and the imaging device 235 receives one or more calibration parameters from the console 210 to adjust one or more imaging parameters (e.g., focal length, focus, frame rate, ISO, sensor temperature, shutter speed, aperture, etc.).

[0118] In some embodiments, display device 205 includes one or more optical components 260, which may include a single optical component 260 or multiple optical components 260 (e.g., an optical component 260 for each eye of a user). In some embodiments, one or more optical components 260 receive image light of a computer-generated image from electronic display 215 and direct the image light to one or more eyes of the user. Computer-generated images include still images, animated images, and / or combinations thereof. Computer-generated images include objects that appear to be two-dimensional and / or three-dimensional objects.

[0119] In some embodiments, the electronic display 215 projects the computer-generated image onto one or more reflective elements (not shown), and the one or more optical components 260 receive the image light from the one or more reflective elements and direct the image light to the user's (multiple) eyes. In some embodiments, the one or more reflective elements are partially transparent (e.g., the transmittance of the one or more reflective elements is at least 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50%), which allows the transmission of ambient light. In such embodiments, the computer-generated image projected by the electronic display 215 is superimposed with the transmitted ambient light (e.g., the transmitted ambient image) to provide an augmented reality image.

[0120] The input interface 240 is a device that allows a user to send an action request to the console 210. An action request is a request to perform a specific action. For example, an action request may be to start or end an application or to perform a specific action within an application. The input interface 240 may include one or more input devices. Example input devices include: a keyboard, a mouse, a game controller, data from brain signals, data from other parts of the human body, or any other suitable device for receiving an action request and transmitting the received action request to the console 210. The action request received by the input interface 240 is transmitted to the console 210, and the console 210 performs an action corresponding to the action request. In some embodiments, the input interface 240 may provide tactile feedback to the user according to an instruction received from the console 210. For example, tactile feedback is provided when an action request is received, or the console 210 transmits an instruction to the input interface 240 so that the input interface 240 generates tactile feedback when the console 210 performs an action.

[0121] The console 210 provides media to the display device 205 for presentation to the user based on information received from one or more of the imaging device 235, the display device 205, and the input interface 240. Figure 2 In the example shown, the console 210 includes an application store 245, a tracking module 250, and an application engine 255. Some embodiments of the console 210 have Figure 2 Similarly, the functionality described further herein may be distributed among the components of console 210 in a manner different than that described herein.

[0122] When an application store 245 is included in the console 210, the application store 245 stores one or more applications executed by the console 210. An application is a set of instructions used to generate content for presentation to a user when executed by the processor 216. The content generated by the processor 216 based on the application may be responsive to input received from the user via movement of the display device 205 or the input interface 240. Examples of applications include: gaming applications, conferencing applications, video playback applications, or other suitable applications.

[0123] When the tracking module 250 is included in the console 210, the tracking module 250 uses one or more calibration parameters to calibrate the system 200, and may adjust the one or more calibration parameters to reduce errors in determining the position of the display device 205. For example, the tracking module 250 adjusts the focus of the imaging device 235 to obtain a more accurate position of the observed localizer 220 on the display device 205. In addition, the calibration performed by the tracking module 250 also takes into account information received from the IMU 230. In addition, if tracking of the display device 205 is lost (e.g., the imaging device 235 loses sight of at least a threshold number of localizers 220), the tracking module 250 recalibrates part or all of the system 200.

[0124] In some embodiments, the tracking module 250 uses the second calibration data from the imaging device 235 to track the movement of the display device 205. For example, the tracking module 250 uses the observed locators 220 from the second calibration data and the model of the display device 205 to determine the position of the reference point of the display device 205. In some embodiments, the tracking module 250 also uses the position information from the first calibration data to determine the position of the reference point of the display device 205. Additionally, in some embodiments, the tracking module 250 can use portions of the first calibration data, the second calibration data, or some combination thereof to predict the future position of the display device 205. The tracking module 250 provides the estimated or predicted future position of the display device 205 to the application engine 255.

[0125] The application engine 255 executes an application within the system 200 and receives position information, acceleration information, velocity information, predicted future position, or some combination thereof of the display device 205 from the tracking module 250. Based on the received information, the application engine 255 determines the content to be provided to the display device 205 for presentation to the user. For example, if the received information indicates that the user has looked to the left, the application engine 255 generates content for the display device 205 that reflects the user's movement in the augmented environment. In addition, the application engine 255 performs an action within an application executed on the console 210 in response to an action request received from the input interface 240, and provides feedback to the user that the action has been performed. The feedback provided may be visual or auditory feedback via the display device 205 or tactile feedback via the input interface 240.

[0126] Figure 3 is an isometric view of a display device 300 according to some embodiments, the display device 300 corresponding to the display device 100 (see Figure 1). In some embodiments, display device 300 includes an emitting array 310 (e.g., an array of light emitting devices or a reflective element), and an optical assembly (e.g., optical assembly 260) having one or more optical components 330 (e.g., a lens). In some embodiments, display device 300 also includes an IR detector array.

[0127] In some embodiments, the light emitting device array 310 emits image light and optional IR light toward the optical component 330. The light emitting device array 310 can be, for example, an LED array, a micro-LED array, an OLED array, or some combination thereof. The light emitting device array 310 includes light emitting devices 320 that emit light in the visible light range (and optionally includes devices that emit light in the IR range).

[0128] In some embodiments, the display device 300 includes an emission intensity array that is configured to selectively attenuate light emitted from the light emitting array 310. In some embodiments, the emission intensity array is composed of a plurality of liquid crystal cells or pixels, groups of light emitting devices 320, or some combination thereof. Each liquid crystal cell or groups of liquid crystal cells in some embodiments are addressable to have a specific level of attenuation. For example, at a given time, some liquid crystal cells can be set to no attenuation, while other liquid crystal cells can be set to maximum attenuation. In this way, the emission intensity array is able to control which portion of the image light emitted from the light emitting device array 310 is passed to one or more optical components 330. In some embodiments, the display device 300 uses the emission intensity array to facilitate providing image light to the positioning of the pupil 350 of the user's eye 340, and minimize the amount of image light provided to other areas in the eye range 380.

[0129] The optional IR detector array detects IR light that has been reflected back from the retina of eye 340, the cornea of ​​eye 340, the lens of eye 340, or some combination thereof. The IR detector array includes a single IR sensor or multiple IR sensitive detectors (e.g., photodiodes). In some embodiments, the IR detector array is separate from the light emitting device array 310. In some embodiments, the IR detector array is integrated into the light emitting device array 310.

[0130] In some embodiments, the light emitting device array 310 and the emission intensity array constitute a display element. Alternatively, the display element includes the light emitting device array 310 (for example, when the light emitting device array 310 includes individually adjustable pixels) without the emission intensity array. In some embodiments, the display element additionally includes an IR array. In some embodiments, in response to the determined positioning of the pupil 350, the display element adjusts the emitted image light so that the light output by the display element is refracted by one or more optical components 330 toward the determined positioning of the pupil 350, but not toward another assumed positioning.

[0131] In some embodiments, in addition to or in lieu of array of light emitting devices 310, display device 300 includes one or more broadband sources (eg, one or more white light LEDs) coupled with a plurality of color filters.

[0132] One or more optical components 330 receive image light (or modified image light, such as attenuated light) from transmit array 310 and direct the image light to a detected or presumed location of pupil 350 of user eye 340. In some embodiments, one or more optical components 330 include one or more optical assemblies 260.

[0133] Figures 4A-4E is a schematic diagram illustrating a display device according to some embodiments.

[0134] Figure 4A is a schematic diagram showing a zoom polarization-sensitive diffuse display device (hereinafter referred to as a "display device") 400 according to certain embodiments. As shown, the display device 400 includes an image source 410 and a display 420, the image source 410 is configured to provide (e.g., project, output, generate, emit) image light corresponding to an image to be displayed, and the display 420 is configured to display the image. In some embodiments, the image light provided by the image source 410 may have any of the following: a first polarization, a second polarization different from (e.g., orthogonal to) the first polarization, or a combination of more than one polarization. For example, in some embodiments, the image light may be configured as a first image light 490-1 having a first polarization or a second image light 490-2 having a second polarization. In some embodiments, the first polarization is right-handed polarization or RCP, and the second polarization is left-handed polarization or LCP, or vice versa. In some embodiments, the display 420 includes a plurality of optical diffusers (e.g., a first optical diffuser 422 and a second optical diffuser 424). The display 420 is configured to: (1) receive the first image light 490-1 and diffuse the first image light 490-1 at the first optical diffuser 422 (eg, Figure 4A), or (2) receiving the second image light 490-2 and diffusing the second image light 490-2 at the second optical diffuser 424 (as shown in FIG. Figure 4B shown).

[0135] In some embodiments, each of the first optical diffuser 422 and the second optical diffuser 424 is configured to diffuse light having a first polarization and transmit light having a second polarization. Figure 4A As shown in illustration A of , the first optical diffuser 422 is configured to diffuse the first image light 490 - 1 having the first polarization as the first diffused image light 492 .

[0136] like Figure 4A As shown, ambient light 494, which may be unpolarized, may be incident on the second optical diffuser 424. A first portion 494-1 of the ambient light 494 having a first polarization (e.g., RCP) is diffused at the second optical diffuser 424, and a second portion 494-2 of the ambient light 494 having a second polarization (e.g., LCP) is transmitted through both the second optical diffuser 424 and the first optical diffuser 422.

[0137] In some embodiments, Figure 4A As shown, the first optical diffuser 422 includes a first surface 422-A and is configured to receive the first image light 490-1 at the first surface 422-A and output the first diffused image light 492 from the first surface 422A (e.g., reflectively diffuse the first image light 490-1 at the first surface 422-A). Figures 5A-5D and Figure 6 A-6D provides additional details regarding the first optical diffuser 422 and the second optical diffuser 424.

[0138] In some embodiments, the display device 400 further includes a first optical retarder 426, which is disposed between the first optical diffuser 422 and the second optical diffuser 424. Figure 4BAs shown, when the display 420 receives the second image light 490-2 having the second polarization, the first optical diffuser 422 is configured to transmit the second image light 490-2. The first optical retarder 426 is configured to receive the second image light 490-2 that has been transmitted through the first optical diffuser 422, and convert the polarization of the second image light 490-2 so that after being transmitted through the first optical retarder 426, the second image light 490-2 has the first polarization and is diffused by the second optical diffuser 424 into the second diffused image light 496 also having the first polarization. The first optical retarder 426 may also be configured to receive the second diffused image light 496, and convert the polarization of the second diffused image light 496 from the first polarization to the second polarization so that the second diffused image light 496 is transmitted by the first optical diffuser 422.

[0139] In an ideal case, light is transmitted through the optical diffuser without diffusion. For example, in an ideal case, the second image light 490-2 having the second polarization is transmitted through the first optical diffuser 422 without any diffusion. In some cases, a small amount of the transmitted light may be diffused. For example, a small, non-zero amount of the second image light 90-2 may be diffused by the first optical diffuser 422. However, the portion of the diffused light compared to the incident light for a configuration in which the optical diffuser causes transmission of (most of) the incident light is less than the portion of the diffused light compared to the incident light for a configuration in which the optical diffuser causes diffusion of the incident light. For example, the optical diffuser causes diffusion of less than 50% (e.g., less than 5%) of the incident light while the optical diffuser allows transmission of the incident light, and the optical diffuser causes diffusion of greater than 50% (e.g., greater than 95%) of the incident light while the optical diffuser allows diffusion of the incident light.

[0140] Therefore, in some embodiments, the first optical diffuser 422 is configured to output a first diffused image light 492 (eg, Figure 4A ), and the second optical diffuser 424 is configured to output a second diffused image light 496 (as shown) by diffusing the second image light 490-2 having a second polarization. Figure 4B In some embodiments, the first diffuse image light 492 has a first polarization and the second diffuse image light 496 has a second polarization.

[0141] In some embodiments, Figure 4C-4E As shown, the display 420 may include more than two optical diffusers (eg, a first optical diffuser 422, and optical diffusers 425-1, 425-2, and 425-n, where n>1).

[0142] In some embodiments, the distance between any two adjacent optical diffusers in display 420 is greater than 50 microns, 100 microns, 500 microns, 1 mm, 2 mm, 4 mm, 5 mm, 10 mm, or 50 mm. Figure 4C As shown, the distance D1 between the first optical diffuser 422 and the optical diffuser 425-1 is greater than 50 micrometers, 100 micrometers, 500 micrometers, 1 millimeter, 2 millimeters, 4 millimeters, 5 millimeters, 10 millimeters, or 50 millimeters, and the distance D2 between the optical diffuser 425-1 and the optical diffuser 425-2 is greater than 50 micrometers, 100 micrometers, 500 micrometers, 1 millimeter, 2 millimeters, 4 millimeters, 5 millimeters, 10 millimeters, or 50 millimeters. Therefore, the distance between the first optical diffuser 422 and any of the optical diffusers 425 (e.g., optical diffusers 425-1, 425-2, and 425-n) is greater than 50 micrometers, 100 micrometers, 500 micrometers, 1 millimeter, 2 millimeters, 4 millimeters, 5 millimeters, 10 millimeters, or 50 millimeters. In some embodiments, as Figure 4C As shown, distance D2 is different from distance D1. In some embodiments, distances D1 and D2 are substantially the same (eg, within + / - 0.5 mm).

[0143] In some embodiments, the display 420 includes one or more third optical diffusers disposed between the first optical diffuser 422 and the second optical diffuser 424 .

[0144] In some embodiments, the display 420 further includes optical retarders 427-1, 427-2, and 427-n corresponding to the optical diffusers 425-1, 425-2, and 425-n, respectively. Each of the optical retarders (e.g., optical retarder 427-2) is disposed between a corresponding optical diffuser (e.g., optical diffuser 425-2) and the first optical diffuser 422, and between a corresponding optical diffuser (e.g., optical diffuser 425-2) and an adjacent optical diffuser (e.g., optical diffuser 425-1). In some embodiments, any (e.g., some or all) of the optical retarders 427-1, 427-2, and 427-n may be switchable optical retarders (e.g., active optical retarders) that are configurable to be in any of a first state and a second state (e.g., an “off” state and an “on” state), and the display device 420 further includes controllers 428-1, 428-2, and 428-n, which are coupled to the optical retarders 427-1, 427-2, and 427-n, respectively, and are configured to control the respective states of the optical retarders 427-1, 427-2, and 427-n. Figure 4G and4H Describe the operation of a switchable optical retarder.

[0145] In some embodiments, by configuring the states of the optical retarders 427-1, 427-2, and 427-n using the controllers 428-1, 428-2, and 428-n, any of the optical diffusers 425-1, 425-2, and 425-n (e.g., optical retarder 425-i, i=1, 2, ..., n) may be selected to function as a second optical diffuser 424 configured to output a second diffused image light 496 (e.g., a diffused second image light 490-2) by diffusing the second image light 490-2. Figure 4B ), and the corresponding optical delay (e.g., optical delay 427-i) will be used as the first optical delay 426. For example, Figure 4D As shown, in order for the optical diffuser 425-n to function as the second optical diffuser 424 and the optical retarder 427-n to function as the first optical retarder 426, the states of the optical retarders 427-1 to 427-(n-1) are set to "on" and the state of the optical retarder 427-n is set to "off". In this manner, the optical retarders 427-1 to 427-(n-1) are configured to transmit the second image light 490-2 propagating toward the optical diffuser 425-n without changing its polarization, and transmit the second diffused image light 496 propagating toward the first optical diffuser 422 without changing its polarization. The optical retarder 427-n is configured to transmit the second image light 490-2 as the third image light having the first polarization, so that the third image light is diffused at the optical diffuser 425-n, and transmit the diffused third image light output from the optical diffuser 425-n as the second diffused image light 496 having the second polarization.

[0146] In another example, if Figure 4E As shown, in order to make the optical diffuser 425-2 function as the second optical diffuser 424 and the optical retarder 427-2 function as the first optical retarder 426, the state of the optical retarder 427-1 is set to “on” and the state of the optical retarder 427-2 is set to “off”. In this way, the optical retarder 427-1 is configured to transmit the second image light 490-2 propagating toward the optical diffuser 425-2 without changing its polarization, and transmit the second diffused image light 496 propagating toward the first optical diffuser 422 without changing its polarization.

[0147] Thus, in some embodiments, the second optical diffuser 424 can be any of the optical diffusers 425-1, 425-2, and 425-n. Thus, there can be one or more third optical diffusers between the first optical diffuser 422 and the second optical diffuser 424, and / or there can be one or more fourth optical diffusers that are not between the first optical diffuser 422 and the second optical diffuser.

[0148] In some embodiments, the optical delay element 427 may include a switchable optical delay element and a non-switchable optical delay element (eg, a non-active optical element). Figure 4D As shown, optical delays 427-1 to 427-(n-1) are switchable optical delays, and optical delay 427n need not be a switchable optical delay.

[0149] like Figure 4G As shown, when the switchable optical retarder (e.g., optical retarder 427) is configured to be in the "off" state, the switchable optical retarder is configured to convert the polarization of the incident light from the incident polarization to an orthogonal polarization. Figure 4D As shown, the switchable optical retarder 427-n in the "off" state is configured to convert the polarization of the second image light 490-2 transmitted through the first optical diffuser 422 from the second polarization to the first polarization.

[0150] like Figure 4H As shown, when the switchable optical retarder is configured to be in the "on" state, the switchable optical retarder is configured to transmit the transmitted incident light without changing its polarization. Figure 4E As shown, the optical retarder 427-1 in the "on" state is configured to transmit the second image light 490-2 transmitted through the first optical diffuser 422 without changing its polarization.

[0151] refer to Figure 4F In some embodiments, the first optical diffuser 422 and the second optical diffuser 424 of the display device 400 have the same optical axis 429, and the image source 410 is disposed at an off-axis position relative to the optical axis 429. Figure 4L-4M Additional details regarding image source 410 are provided.

[0152] refer to Figure 4F In some embodiments, the display device 400 includes a lens assembly 432 and a switchable optical retarder 430 disposed between the display 420 and the lens assembly 432. The switchable optical retarder 430 is electrically coupled to the controller 431 and is configured to Figure 4G and 4HThe operation of the switchable optical delay 430 is described. In some embodiments, as Fig. 4I As shown, when the image source 410 is configured to output the first image light 490-1, the switchable optical retarder 430 is configured to be in a first state (e.g., an "off" state in this example). In the first state, the switchable optical retarder 430 is configured to receive the first diffuse image light 492 and output the third diffuse image light 497-1 having a third polarization. In some embodiments, as Figure 4J As shown, when the image source 410 is configured to output the second image light 490-2, the switchable optical retarder 430 is configured to be in the second state. In the second state (e.g., the "on" state in this example), the switchable optical retarder 430 is configured to receive the second diffuse image light 496 and output the fourth diffuse image light 497-2 having a third polarization. Therefore, regardless of whether the image source 410 is configured to output the first image light 490-1 or the second image light 490-2, the switchable optical retarder 430, in the first state or the second state, is configured to output diffuse image light having a third polarization. Although Fig. 4I and 4J It is shown that the third polarization is the same as the second polarization, but the third polarization may be the same as the first polarization or the second polarization (eg, the third polarization may be LCP or RCP).

[0153] In some embodiments, Figure 4K As shown, the switchable optical retarder 430 can also be configured to receive a second portion 494-2 of the ambient light 494 that has been transmitted through the display 420, and output a second ambient light 499 having a fourth polarization that is different from (e.g., orthogonal to) the third polarization, regardless of whether the switchable optical retarder 430 is in the first state or the second state. Figure 4I-4K As shown, when the diffuse image lights 497-1 and 497-2 output from the switchable optical retarder 430 are LCP lights, the second ambient light 499 output from the switchable optical retarder 430 is RCP light. Alternatively, when the diffuse image lights 497-1 and 497-2 output from the switchable optical retarder 430 are RCP lights, the second ambient light 499 output from the switchable optical retarder 430 is LCP light.

[0154] In some embodiments, Figure 4I-4K As shown, lens assembly 432 is a polarization selective lens assembly. Lens assembly 432 is configured to transmit incident light at a first optical power or a second optical power based on the polarization of the light incident on lens assembly 432. For example, Figure 4I-4KAs shown, the lens assembly 432 is configured to receive diffuse image lights 497-1 and 497-2 output from the switchable optical retarder 430 and having a third polarization, and guide (e.g., focus, substantially collimate) the diffuse image lights 497-1 and 497-2 at a first optical power. The lens assembly 432 is also configured to transmit a second ambient light 499 output from the switchable optical retarder 430 and having a fourth polarization at a second optical power different from (e.g., less than) the first optical power. In some embodiments, the second optical power is zero. In some embodiments, the lens assembly 432 is configured to transmit the second ambient light 499 without adding significant optical aberrations. In some embodiments, the lens assembly 432 may include a pancake lens or a metasurface lens.

[0155] Figure 4L-4M is a schematic diagram illustrating an image source 410 in a display device according to some embodiments.

[0156] In some embodiments, the image source 410 includes a projector 412, a polarization-sensitive optical element 416, and a switchable optical retarder 414, wherein the projector 412 is configured to output image light 490' having an initial polarization (e.g., LCP or RCP) and the switchable optical retarder 414 is disposed between the projector 412 and the polarization-sensitive optical element 416. The switchable optical retarder 414 is electrically coupled to the controller 415, and the above-mentioned Figure 4G and 4H Operation of switchable optical retarder 414 is described. In some embodiments, projector 412 is configured to generate linearly polarized light and includes a circular polarizer, such as a quarter-wave retarder, configured to convert the linearly polarized light into image light 490' having an initial polarization, which is circular polarization (e.g., LCP or RCP).

[0157] In some embodiments, the switchable optical retarder 414 is configured to receive image light 490' having an initial polarization, and output image light 490" having a first polarization or a second polarization toward the polarization-sensitive optical element 416. The switchable optical retarder 414 may be configured to be in one of a first state and a second state (e.g., an "on" state and an "off" state, or vice versa), and the polarization of the image light 490" depends on the state of the switchable optical retarder 414. The polarization-sensitive optical element 416 is configured to receive the image light 490" output from the switchable optical retarder 414 regardless of the polarization of the image light 490", and project (e.g., steer, guide, diffract) the image light 490" as a first image light 490-1 or a second image light 490-2, depending on the polarization of the image light 490". When the image light 490" has the second polarization, the polarization-sensitive optical element 416 is configured to project the image light 490" as the first image light 490-1 propagating in a first direction (e.g., for use by the image light 490). Figure 4A When image light 490" has a first polarization, polarization-sensitive optical element 416 is configured to project image light 490" as second image light 490-2 propagating in a second direction (e.g., for use by Figure 4A In some embodiments, when the first optical diffuser 422 is spaced apart from the second optical diffuser 424, the first direction is different from the second direction such that the first image light 490-1 projected onto the first optical diffuser 422 is horizontally aligned with the second image light 490-2 projected onto the second optical diffuser 424. In some embodiments, the polarization-sensitive optical element 416 is a Pancharatnam-Berry phase optical element (e.g., a geometric phase optical element, a geometric phase grating).

[0158] For example, Figure 4L As shown, projector 412 outputs image light 490' having a second polarization (e.g., LCP). When switchable optical retarder 414 is in a first state (e.g., an "on" state), image light 490' is transmitted as image light 490" without polarization change. Polarization-sensitive optical element 416 receives image light 490" having a second polarization and projects (e.g., turns, guides, diffracts) image light 490" as first image light 490-1 propagating in a first direction (e.g., having a first angle A1 relative to the surface normal of polarization-sensitive optical element 416). Therefore, when switchable optical retarder 414 is in a first state, first image light 490-1 having a first polarization (e.g., RCP) is output from polarization-sensitive optical element 416.

[0159] In another example, if Figure 4MAs shown, projector 412 outputs image light 490' having a second polarization (e.g., LCP). When switchable optical retarder 414 is in a second state (e.g., an "off" state), image light 490' is converted into image light 490" having a first polarization. Polarization-sensitive optical element 416 receives image light 490" having the first polarization and projects (e.g., turns, guides, diffracts) image light 490" as second image light 490-2 propagating in a second direction (e.g., having a second angle A2 relative to the surface normal of polarization-sensitive optical element 416). Therefore, when switchable optical retarder 414 is in the second state, second image light 490-2 having a second polarization (e.g., LCP) is output from polarization-sensitive optical element 416.

[0160] Figure 4N-4P Operation of a display device 402 corresponding to the display device 400 is shown. As shown, the display device 402 has a display assembly that includes three optical diffusers: a first optical diffuser 470-1, a second optical diffuser 470-2, and a third optical diffuser 470-3. The display assembly also includes two optical retarders: a first optical retarder 472-1 disposed between the first optical diffuser 470-1 and the second optical diffuser 470-2, and a second optical retarder 472-2 disposed between the second optical diffuser 470-2 and the third optical diffuser 470-3. Details regarding the optical diffusers and optical retarders are described above with respect to Figures 4A-4F Provided and not repeated here for brevity. The display device 402 also includes an image source 410, which is configured to provide (e.g., output, generate, emit, project) image light toward the display component. The display device 402 is configured to selectively diffuse image light from any optical diffuser in the first optical diffuser 470-1, the second optical diffuser 470-2, and the third optical diffuser 470-3. By causing the diffusion of image light at different optical diffusers of the display device 402, the focal plane of the image projected toward the user's eye 340 can be changed. Therefore, the display device 402 is able to quickly switch between the three optical diffusers to provide a multi-focus image to the user. The switching can be a fast time-sequential switching process so that the user perceives a single scene in which objects are located at different focal planes. For example, the images are ordered in time so that they are presented to the user at a sufficiently high frame rate at which the human eye 340 cannot distinguish each frame individually (e.g., faster than the flicker fusion threshold). In some embodiments, the frame frequency is greater than 50 Hz. In some embodiments, the frame frequency is 100 Hz or higher. For example, the image may include a dog, a tree, and a house. The first portion of the image light corresponding to the dog may be diffused at the first optical diffuser 470-1 (eg, Figure 4N), so that the diffuse image light 498-1 presents an image of a dog to the user at the first focal plane, and a second portion of the image light corresponding to the tree can be diffused at the second optical diffuser 470-2 (as shown in FIG. Fig.4O ), so that the diffuse image light 498-2 presents an image of a tree to the user at a second focal plane, the second focal plane being different from the first focal plane, and a third portion of the image light corresponding to the house can be diffused at a third optical diffuser 470-3 (as shown in FIG. Figure 4P ), such that diffuse image light 498-3 presents an image of the house to the user at a third focal plane that is different from the first focal plane and the second focal plane. Thus, by continuously providing portions of image light corresponding to the dog, the tree, and the house, and diffusing corresponding portions of the image light at different optical diffusers, a multi-focal image or multi-focal scene can be seamlessly presented to the user.

[0161] Figures 5A-5D 4 is a cross-sectional view of a polarization-sensitive hologram 500 corresponding to the first optical diffuser 422 and any of the second optical diffusers 424 and 425, according to some embodiments. Figure 5A As shown, the polarization-sensitive hologram 500 includes a first surface 500-1, a second surface 500-2 opposite to the first surface 500-1, and optically anisotropic molecules 509 disposed between the first surface 500-1 and the second surface 500-2. In some embodiments, the polarization-sensitive hologram 500 is configured to output light from the first surface 500-1 in response to receiving incident light at the first surface 500-1. As shown, when the incident light (e.g., light 510) has a first circular polarization (e.g., RCP), diffuse light 512 having a first circular polarization is output from the first surface 500-1. In some embodiments, the light 510 is substantially collimated and propagates in a first direction. In some embodiments, the polarization-sensitive hologram 502 is configured to diffuse the light 510 to output diffuse light 512 propagating in multiple directions. When incident light (eg, light 520) has a second circular polarization (eg, LCP), the polarization-sensitive hologram 500 is configured to transmit the light 520 from the second surface 500-2. In some embodiments, the light 520 is transmitted without changing polarization or direction.

[0162] In some embodiments, the polarization-sensitive hologram 500 may be incident angle selective and / or wavelength selective.

[0163] Figure 5BThe wavelength selectivity of the polarization-sensitive hologram 500 according to some embodiments is shown. In some embodiments, the polarization-sensitive hologram 500 is configured to diffuse light having a first circular polarization and having a wavelength within a first predefined spectral range, and to transmit light having a wavelength outside the first predefined spectral range, regardless of the polarization of the light.

[0164] As shown, light 510 having a first circular polarization and having a first wavelength λ1 within a first predefined spectral range is incident on the polarization-sensitive hologram 500. Therefore, the light 510 is diffused at the polarization-sensitive hologram 500, and diffused light 512 having the first circular polarization is output from the polarization-sensitive hologram 500. On the other hand, light 530 having a wavelength λ outside the first predefined spectral range is transmitted through the polarization-sensitive hologram 500 without changing direction or polarization.

[0165] For example, Figure 5C As shown, the polarization-sensitive hologram 500 can be incident angle selective, so that the polarization-sensitive hologram 500 interacts differently with incident light having different incident angles relative to the direction perpendicular to the first surface 500-1, indicated by the dashed line 590. In some embodiments, the polarization-sensitive hologram 500 is configured to diffuse light having a first circular polarization and incident on the polarization-sensitive hologram 500 at an incident angle within a first predefined incident angle range (e.g., less than the angle φ). In some embodiments, the polarization-sensitive hologram 500 is configured to transmit third light incident on the polarization-sensitive hologram 500 at an incident angle outside the first predefined incident angle range (e.g., equal to or greater than φ), regardless of the polarization of the light.

[0166] As shown, light 510 having a first circular polarization may be incident on the polarization-sensitive hologram 500 in a direction forming a first incident angle θ1 relative to the line 590. The first incident angle θ1 is within a first predefined incident angle range (e.g., θ1<φ). Therefore, the light 510 is diffused at the polarization-sensitive hologram 500, and diffused light 512 having the first circular polarization in response to the light 510 is output from the polarization-sensitive hologram 500. On the other hand, light 540 is incident on the polarization-sensitive hologram 500 at a second incident angle θ2 outside the first predefined incident angle range (e.g., θ2≥φ). Therefore, the light 540 is transmitted through the polarization-sensitive hologram 500 without changing direction or polarization.

[0167] Figure 5D 5 shows the optical path of light transmitted through polarization-sensitive hologram 502 according to some embodiments. In some embodiments, as Figure 5DAs shown, the polarization-sensitive hologram 502 includes a plurality of optical diffusion layers (e.g., a first optical diffusion layer 551, a second optical diffusion layer 552, and a third optical diffusion layer 553). The first optical diffusion layer 551 has a first surface 502-1, a second surface 502-2, and optically anisotropic molecules 509-1 disposed between the first surface 502-1 and the second surface 502-2. The third optical diffusion layer 553 has a third surface 502-3, a fourth surface 502-4, and optically anisotropic molecules 509-3 disposed between the third surface 502-3 and the fourth surface 502-4. The second optical diffusion layer 552 has optically anisotropic molecules 509-2 disposed between the second surface 502-2 and the third surface 502-3.

[0168] In some embodiments, the first optical diffusion layer 551 is configured to diffuse light having a wavelength within a first predefined spectral range, the second optical diffusion layer 552 is configured to diffuse light having a wavelength within a second predefined spectral range, the second predefined spectral range being different from the first predefined spectral range, and the third optical diffusion layer 553 is configured to diffuse light having a wavelength within a third predefined spectral range, the third predefined spectral range being different from the first predefined spectral range and the second predefined spectral range. In some embodiments, the polarization-sensitive hologram 502 is configured to diffuse light having a wavelength within a wider spectral range covering the first predefined spectral range, the second predefined spectral range, and the third predefined spectral range. As shown in inset B, the optically anisotropic molecules 509-1 disposed between the first surface 502-1 and the second surface 502-2 are arranged so that the first optical diffusion layer 551 diffuses light 560 having a first circular polarization and having a first wavelength λ1 within the first predefined spectral range. Therefore, diffused light 561 having the first wavelength λ1 is output from the first optical diffusion layer 551 via the second surface 502-2. The optical anisotropic molecules 509-2 disposed between the second surface 502-2 and the third surface 502-3 are arranged so that the second optical diffusion layer 552 diffuses the light 562 having the first circular polarization and having the second wavelength λ2 within the second predefined spectral range, and transmits the diffused light 561 without changing the direction or polarization. Therefore, the diffused light 563 having the second wavelength λ2 is output from the second optical diffusion layer 552 through the third surface 502-3. The optical anisotropic molecules 509-3 disposed between the third surface 502-3 and the fourth surface 502-4 are arranged so that the third optical diffusion layer diffuses the light 640 having the first circular polarization and having the third wavelength λ3 within the third predefined spectral range, and transmits the diffused light 561 and the diffused light 563 without changing the direction or polarization. Therefore, the diffused light 565 having the third wavelength λ3 is output from the fourth surface 502-4 together with the diffused light 561 and the diffused light 563. Therefore, when incident light (e.g., light 560, 562, 564) having a first polarization and having a wavelength within a wider spectral range covering the first predefined spectral range, the second predefined spectral range, and the third predefined spectral range is incident on the polarization-sensitive hologram 502, the polarization-sensitive hologram 502 outputs diffuse light (e.g., diffuse light 561, 563, 565) having a wavelength corresponding to the wavelength of the incident light. The polarization-sensitive hologram 502 is also configured to receive light 570 having a wavelength outside the wider spectral range covering the first predefined spectral range, the second predefined spectral range, and the third predefined spectral range, and transmit the light 570 without changing the polarization or direction, regardless of the polarization of the light 570.

[0169] In some embodiments, the polarization-sensitive hologram 502 may be configured to diffuse light incident on the polarization-sensitive hologram 502 at an incident angle within a wider incident angle range, the wider incident angle range covering a first predefined incident angle range, a second predefined incident angle range, or a third predefined incident angle range, the second predefined incident angle range being different from the first predefined incident angle range, the third predefined incident angle range being different from the first predefined incident angle range and the second incident angle spectral range. For example, the optically anisotropic molecules 509-1 disposed between the first surface 502-1 and the second surface 502-2 may be arranged such that the first optical diffusion layer diffuses light having a first circular polarization and incident on the polarization-sensitive hologram 502 at a first angle θ1 within the first predefined incident angle range, and outputs the diffused first light. The optical anisotropic molecules 509-2 disposed between the second surface 502-2 and the third surface 502-3 are arranged so that the second optical diffusion layer diffuses light having the first circular polarization and incident on the polarization-sensitive hologram 502 at a second angle within the second predefined incident angle range, and outputs the diffused light. The optical anisotropic molecules 509-3 disposed between the third surface 502-3 and the fourth surface 502-4 are arranged so that the third optical diffusion layer diffuses light having the first circular polarization and incident on the polarization-sensitive hologram 502 at a third angle within the third predefined incident angle range, and outputs the diffused light. Therefore, when incident light having the first polarization is incident on the polarization-sensitive hologram 502 at an incident angle within a wider incident angle range covering the first predefined incident angle range, the second predefined incident angle range, or the third predefined incident angle range, the polarization-sensitive hologram 502 outputs diffused light. The polarization-sensitive hologram 502 is also configured to receive light incident on the polarization-sensitive hologram 502 at an incident angle outside a wider incident angle range covering the first predefined incident angle range, the second predefined incident angle range, and the third predefined incident angle range, and to transmit the light without changing the polarization or direction, regardless of the polarization or wavelength of the light.

[0170] Although the polarization-sensitive hologram 502 is Figure 5D 5. Although shown as including three optically diffuse layers, it should be understood that the polarization-sensitive hologram 502 may include any number of optically diffuse layers.

[0171] Figure 66 is a schematic diagram showing an optical diffuser 600 corresponding to any of the optical diffusers 422, 424, 425-n according to some embodiments. Each rod 612 is a representation of the orientation of optically anisotropic molecules in the optical diffuser 600. Dashed lines 616 demarcate the transitions between different domains 614-1, 614-2, and 614-3. In general, the boundaries can be located anywhere in the polarization-sensitive optical diffuser. In some embodiments, the boundaries are periodic such that the boundaries are evenly spaced (e.g., forming a periodic structure of domains). Although three domains are shown for illustrative purposes, the optical diffuser 600 can have any number of domains.

[0172] As shown, the optically anisotropic molecules in each domain are aligned to form a grating-like pattern. Thus, in each domain, the optically anisotropic molecules are configured to diffract incident light having a desired handedness and within a predetermined angle and wavelength range in a particular direction. As shown, the alignment of the optically anisotropic molecules is slightly different between two adjacent domains, and therefore, the optically anisotropic molecules in adjacent domains are configured to diffract incident light in different directions, resulting in an overall effect of outputting diffuse light from the optical diffuser 600. For example, the optically anisotropic molecules in domain 614-1 can be configured to guide (e.g., diffract) incident light in a first direction, the optically anisotropic molecules in domain 614-2 are configured to guide (e.g., diffract) incident light in a second direction, the second direction being different from the first direction, and the optically anisotropic molecules in domain 614-3 are configured to guide (e.g., diffract) incident light in a third direction, the third direction being different from each of the first and second directions. Therefore, the combined effect of diffracted light in slightly different directions at different domains of the optical diffuser 600 causes the incident light to be diffused and output as diffused light. In addition, just as a grating can be designed to redirect light in a predetermined direction (e.g., a predetermined angle), the optical diffuser 600 can also be designed to output diffused light such that the chief ray of the output diffused light propagates in a predetermined direction (e.g., forming a predetermined angle relative to the surface of the optical diffuser 600).

[0173] In some embodiments, the optical diffuser may include an alignment (photoalignment) layer (e.g., a photoalignment layer, a layer including an organic or inorganic compound (including a photosensitive group)) and a helical structure formed by optically anisotropic molecules. In this case, the alignment layer is formed by adding a layer of photoalignment material on the surface of the optical diffuser. Then, the alignment layer is exposed to alignment light (e.g., linearly polarized light, circularly polarized light, or elliptically polarized light) with a desired intensity and incident angle. The alignment light is scanned on the alignment layer while rotating the polarization of the alignment light to effectively write an xy alignment pattern to the alignment layer in two dimensions. After the preparation of the alignment layer, a layer of optically anisotropic molecules is applied to the alignment layer to form a helical structure. The xy alignment pattern of the alignment layer defines the orientation of the helical structure of the optically anisotropic molecules. After the helical structure is formed, the layer of optically anisotropic molecules is cured (e.g., fixed, solidified, or hardened) to form a polymer. In some embodiments, curing includes thermal curing or UV curing. In some embodiments, the helical structure is formed by liquid crystals such as cholesteric liquid crystals. The helical structure is aligned along the helical axis. In some embodiments, each of the helical axes is substantially parallel to the z-axis (e.g., each helical axis forms an angle of less than 1 degree with the z-axis). Alternatively, the helical axes may form a non-zero angle relative to the z-axis. In some embodiments, the optically anisotropic molecules rotate in the same rotational direction (forming a helical twist) about the corresponding helical axes.

[0174] In some embodiments, the polarization-sensitive optical diffuser does not include an alignment layer, and the helical structure of the polarization-sensitive optical diffuser is formed without the alignment layer.

[0175] In some embodiments, the optical diffuser comprises bulk liquid crystal. In this case, the xyz alignment pattern can be written in three dimensions into the bulk liquid crystal material.

[0176] Figure 77 is a flow chart of a method 700 of displaying an image according to some embodiments. The method 700 includes (operation 710) providing image light (e.g., image light 490-1, 490-2) from the image source 410 and (operation 720) receiving the image light at the first optical diffuser 422. The method 700 also includes: when the image light received at the first optical diffuser 422 has a first polarization (e.g., image light 490-1), (operation 730) diffusing the image light at the first optical diffuser 422 to output a first diffused image light (e.g., first diffused image light 492) having the first polarization. The method 700 also includes (operation 740), when the image light 490-2 received at the first optical diffuser 422 has a second polarization different from the first polarization: (i) transmitting the image light 490-2 through the first optical diffuser 422, (ii) converting the image light 490-2 from the second polarization to the first polarization, (iii) diffusing the image light 490-2 having the first polarization at the second optical diffuser 424 to output second diffused image light 496 having the first polarization, (iv) converting the second diffused image light 496 from the first polarization to the second polarization, and (v) transmitting the second diffused image light 496 having the second polarization through the first optical diffuser 422.

[0177] In some embodiments, each of the first optical diffuser and the second optical diffuser is configured to diffuse light having a first polarization and transmit light having a second polarization.

[0178] Based on these principles, we now turn to certain embodiments of variable focus polarization-sensitive diffuse display devices.

[0179] According to some embodiments, a display device (e.g., display device 400) includes an image source (e.g., image source 410) and a display (e.g., display 420). The image source is configured to project image light (e.g., image light 490-1, 490-2). The display includes a first optical diffuser (e.g., first optical diffuser 422) and a second optical diffuser (e.g., second optical diffuser 424). The display is configured to receive the image light, diffuse the image light at the first optical diffuser when the image light has a first polarization, and diffuse the image light at the second optical diffuser when the image light has a second polarization different from (e.g., orthogonal to) the first polarization.

[0180] According to some embodiments, a display device (e.g., display device 400) includes an image source (e.g., image source 410) configured to project image light (e.g., image light 490-1, 490-2). The image light may be configured to have a first polarization or a second polarization (e.g., LCP or RCP, or vice versa), the first polarization being different from the first polarization. The display device also includes a display (e.g., display 420), the display including a first optical diffuser (e.g., first optical diffuser 422) and a second optical diffuser (e.g., second optical diffuser 424). The display is configured to receive the image light, diffuse the image light at the first optical diffuser when the image light is configured to have the first polarization, and diffuse the image light at the second optical diffuser when the image light is configured to have the second polarization.

[0181] In some embodiments, each of the first optical diffuser (eg, first optical diffuser 422 ) and the second optical diffuser (eg, second optical diffuser 424 ) is configured to diffuse first light having a first polarization and transmit second light having a second polarization.

[0182] In some embodiments, the display (e.g., display 420) is further configured to output first diffused image light (e.g., first diffused image light 492) having a first polarization when the image light is configured to have a first polarization (e.g., first image light 490-1). The display is further configured to output second diffused image light (e.g., second diffused image light 496) having a second polarization when the image light is configured to have a second polarization (e.g., second image light 490-2). The first optical diffuser includes a first surface (e.g., first surface 422-A) and is configured to receive the image light at the first surface. The first diffused image light and the second diffused image light are each output from the first surface.

[0183] In some embodiments, the display (e.g., display 420) further includes a first optical retarder (e.g., first optical retarder 426) disposed between a first optical diffuser (e.g., first optical diffuser 422) and a second optical diffuser (e.g., second optical diffuser 424). Each of the first optical diffuser and the second optical diffuser is configured to reflectively diffuse light having a first polarization and transmit light having a second polarization. The first optical retarder is configured to receive image light (e.g., image light 490-2) transmitted through the first optical diffuser. The first optical retarder may be configured to: (i) convert the image light from the second polarization to the first polarization, so that the image light (e.g., image light 490-2) is diffused by the second optical diffuser as second diffused image light (e.g., second diffused image light 496) having the first polarization, (ii) receive the second diffused image light, and (iii) convert the second diffused image light from the first polarization to the second polarization, so that the second diffused image light is transmitted by the first optical diffuser.

[0184] In some embodiments, the display (e.g., display 420) further includes a first optical retarder (e.g., first optical retarder 426) disposed between a first optical diffuser (e.g., first optical diffuser 422) and a second optical diffuser (e.g., second optical diffuser 424). When the image light is configured to have a second polarization (e.g., second image light 490-2), the first optical diffuser is configured to transmit the image light, and the first optical retarder is configured to receive the image light transmitted through the first optical diffuser. The first optical retarder may be configured to convert the polarization of the image light from the second polarization to the first polarization, so that the image light is diffused by the second optical diffuser as a second diffused image light having the first polarization (e.g., second diffused image light 496). The first optical retarder is also configured to receive the second diffused image light, convert the polarization of the second diffused image light from the first polarization to the second polarization, and output the second diffused image light so that the second diffused image light is transmitted by the first optical diffuser.

[0185] In some embodiments, the display (e.g., display 420) further includes one or more third optical diffusers (e.g., optical diffusers 425-1 and 425-2), which are disposed between the first optical diffuser (e.g., first optical diffuser 422) and the second optical retarder (e.g., second optical diffusers 424, 425-n).

[0186] In some embodiments, the display (e.g., display 420) further includes one or more second optical retarders (e.g., optical retarders 427-1 and 427-2). Each of the one or more second optical retarders corresponds to a corresponding optical diffuser in the one or more third optical diffusers and is disposed between the corresponding optical diffuser and the first optical diffuser (e.g., optical retarder 427-1 corresponds to optical diffuser 425-1 and is disposed between optical diffuser 425-1 and first optical diffuser 422). Each optical retarder is configured to transmit image light (e.g., second image light 490-2) transmitted through the first optical diffuser and propagated toward the second optical diffuser (e.g., second optical diffusers 424, 425-n) without changing the polarization of the image light. Each optical retarder is also configured to transmit the first diffused image light (e.g., first diffused image light 492) output from the second optical diffuser and propagated toward the first optical diffuser without changing the polarization of the first diffused image light.

[0187] In some embodiments, the display (e.g., display 420) further includes one or more fourth optical diffusers (e.g., optical diffusers 425-n). The second diffuser (e.g., second optical diffusers 424, 425-2) is disposed between the first optical diffuser (e.g., first optical diffuser 422) and the one or more fourth optical diffusers.

[0188] In some embodiments, a display (e.g., display 420) further includes one or more third optical retarders (e.g., optical retarder 427-n). Each of the one or more third optical retarders corresponds to a corresponding optical diffuser in the one or more fourth optical diffusers and is disposed between the corresponding optical diffuser in the one or more fourth optical diffusers and the second optical diffuser (e.g., optical retarder 427-n corresponds to optical diffuser 425-n and is disposed between optical retarder 427-n and the second optical diffuser 424).

[0189] In some embodiments, the first optical retarder (e.g., first optical retarder 426) is an active optical retarder (e.g., a switchable optical retarder) that can be configured to be in any of a first state and a second state (e.g., an "on" state and an "off" state, and vice versa). In the first state (e.g., the "off" state), the optical retarder is configured to convert the polarization of the image light transmitted through the first optical diffuser from the second polarization to the first polarization (e.g., convert the polarization of the second image light 490-2 from the second polarization to the first polarization). In the second state, the optical retarder is configured to transmit the image light transmitted through the first optical diffuser without changing the polarization of the image light (e.g., transmitting the second image light 490-2).

[0190] In some embodiments, the display device (e.g., display device 400) further includes a first switchable optical retarder (e.g., switchable optical retarder 430) configured to receive any of the first diffuse image light (e.g., first diffuse image light 492) and the second diffuse image light (e.g., second diffuse image light 496) and output a third diffuse image light (e.g., third diffuse image light 497). The first switchable optical retarder may be configured to be in a third state when the image light has a first polarization, or in a fourth state when the image light has a second polarization (e.g., in an "on" state when the first image light 490-1 is output from the image source 410, or in an "off" state when the second image light 490-2 is output from the image source 410, or vice versa). Regardless of whether the first switchable optical retarder is in the first state or the second state, the third diffuse image light has a third polarization (e.g., LCP or RCP). The display device also includes a lens assembly (e.g., lens assembly 432) configured to receive the third diffuse image light output from the first switchable optical retarder and focus the third diffuse image light at a first optical power. The lens assembly is also configured to transmit light having a fourth polarization different from the third polarization (e.g., second ambient light 499) at a second optical power, the second optical power being different from the first optical power. The first switchable optical retarder is disposed between the display and the lens assembly.

[0191] In some embodiments, a display (e.g., display 420) is configured to transmit a portion (e.g., second portion 494-2) of ambient light (e.g., ambient light 494) incident on the display, and the lens assembly is configured to transmit a portion of the ambient light at a second optical power (e.g., second portion 494-2 as second ambient light 499).

[0192] In some embodiments, an image source (e.g., image source 410) includes a projector (e.g., projector 412) configured to output image light (e.g., image light 490') having an initial polarization. The image source also includes a second switchable optical retarder (e.g., switchable optical retarder 414) disposed between the projector and the polarization-sensitive optical element. The second switchable optical retarder is configured to receive the image light having the initial polarization and can be configured to be in a first state or a second state (e.g., an "on" or "off" state, or vice versa). When the second switchable optical retarder is in the first state, image light output from the image source (e.g., image light 490″) is configured to have a first polarization, and when the second switchable optical retarder is in the second state, the image light output from the image source is configured to have a second polarization. The image source also includes a polarization-sensitive optical element (e.g., polarization-sensitive optical element 416) configured to project the image light in a first direction toward the first optical diffuser (e.g., projecting image light 490′ as first image light 490-1) when the image light is configured to have the first polarization, and to project the image light in a second direction toward the second optical diffuser (e.g., projecting image light 490′ as second image light 490-2) when the image light is configured to have the second polarization.

[0193] In some embodiments, the first optical diffuser (e.g., first optical diffuser 422) and the second optical diffuser (e.g., second optical diffuser 424) have the same optical axis (e.g., optical axis 429), and the image source (e.g., image source 410) is located off-axis relative to the optical axis.

[0194] In some embodiments, a first optical diffuser (eg, first optical diffuser 422 ) is spaced apart from a second optical diffuser (eg, second optical diffuser 424 ) by a distance greater than 50 microns (eg, distances D1 and D2 are each no less than 50 microns).

[0195] In some embodiments, each of the first optical diffuser and the second optical diffuser (e.g., the first optical diffuser 422, the second optical diffuser 424, and 425) includes a polarization-sensitive hologram (e.g., polarization-sensitive holograms 500, 502).

[0196] In some embodiments, the first optical diffuser (e.g., the first optical diffuser 422) and the second optical diffuser (e.g., the second optical diffusers 424 and 425) include a first optical surface (e.g., the first optical surface 500-1, 502-1), a second optical surface opposite to the first optical surface (e.g., the second optical surface 500-2, 502-2), and optically anisotropic molecules (e.g., the optically anisotropic molecules 509, 509-1) disposed between the first optical surface and the second optical surface. The optically anisotropic molecules are arranged so that the corresponding optical diffuser is configured to diffuse a first light having a first polarization (e.g., light 510) and transmit a second light having a second polarization (e.g., light 520).

[0197] In some embodiments, the first light includes a third light (e.g., light 560) within a first wavelength range and a fourth light (e.g., light 562) within a second wavelength range. The respective optical diffusers of the first optical diffuser and the second optical diffuser (e.g., the first optical diffuser 422, the second optical diffuser 424, and the second optical diffuser 425) include a first optical surface (e.g., the first optical surface 502-1), a second optical surface (e.g., the second optical surface 502-2), a third optical surface (e.g., the third optical surface 502-3), a first optical anisotropic molecule (e.g., the optical anisotropic molecule 509-1) disposed between the first optical surface and the second optical surface, and a second optical anisotropic molecule (e.g., the optical anisotropic molecule 509-2) disposed between the second optical surface and the third optical surface. The first optical anisotropic molecule is arranged to diffuse the third light, and the second optical anisotropic molecule is arranged to diffuse the fourth light.

[0198] In some embodiments, the first light includes fifth light within a first range of incident angles and sixth light within a second range of incident angles. The respective optical diffusers in the first and second optical diffusers (e.g., the first optical diffuser 422, the second optical diffusers 424, and 425) include a first optical surface (e.g., the first optical surface 502-1), a second optical surface (e.g., the second optical surface 502-2), a third optical surface (e.g., the third optical surface 502-3), first optical anisotropic molecules (e.g., the optical anisotropic molecules 509-1) disposed between the first optical surface and the second optical surface, and second optical anisotropic molecules (e.g., the optical anisotropic molecules 509-2) disposed between the second optical surface and the third optical surface. The first optical anisotropic molecules are arranged to diffuse the fifth light, and the second optical anisotropic molecules are arranged to diffuse the sixth light.

[0199] In some embodiments, the optically anisotropic molecules in the optical diffuser are arranged in a plurality of domains. Each of the plurality of domains includes a portion of the optically anisotropic molecules that forms a grating-like pattern. The portions of the optically anisotropic molecules in adjacent domains are configured to diffract light in different directions.

[0200] According to some embodiments, a display device includes a first optical diffuser and a second optical diffuser. The display device is configured to: receive image light; diffuse the image light at the first optical diffuser when the image light has a first polarization; and diffuse the image light at the second optical diffuser when the image light has a second polarization different from the first polarization. In some embodiments, the display device does not include an image source (e.g., the image source is separate from the display device).

[0201] According to some embodiments, a method of displaying an image (e.g., method 700) includes: (operation 710) providing image light (e.g., image light 490-1, 490-2) and (operation 720) receiving the image light at a first optical diffuser (e.g., first optical diffuser 422). The method also includes (operation 730): when the image light has a first polarization (e.g., image light 490-1), diffusing the image light at the first optical diffuser to output first diffused image light (e.g., first diffused image light 492) having the first polarization. The method also includes: (operation 740), when the image light has a second polarization different from (e.g., orthogonal to) the first polarization (e.g., image light 490-2): (i) transmitting the image light through a first polarization optical diffuser, (ii) converting the image light from the second polarization to the first polarization, (iii) diffusing the image light having the first polarization at a second optical diffuser (e.g., second optical diffuser 424) to output second diffused image light having the first polarization, (iv) converting the second diffused image light from the first polarization to the second polarization, and (v) transmitting the second diffused image light having the second polarization through the first optical diffuser.

[0202] According to some embodiments, a method of displaying an image (e.g., method 700) includes projecting first image light (e.g., image light 490-1) having a first polarization, and diffusing the first image light at a first optical diffuser (e.g., first optical diffuser 422) to output first diffused image light (e.g., first diffused image light 492) having the first polarization. The method also includes projecting second image light (e.g., image light 490-2) having a second polarization different from (e.g., orthogonal to) the first polarization. The method also includes transmitting the second image light through the first optical diffuser, converting the second image light into a third image light having the first polarization, and diffusing the third image light at a second optical diffuser (e.g., second optical diffuser 424) to output a second diffused image light. The second diffused image light has the first polarization. The method also includes converting the second diffused image light into a third diffused image light having the second polarization, and transmitting the third diffused image light through the first optical diffuser.

[0203] In some embodiments, each of the first optical diffuser (eg, first optical diffuser 422 ) and the second optical diffuser (eg, second optical diffuser 424 ) is configured to diffuse light having a first polarization and transmit light having a second polarization.

[0204] Although various figures show the operation of a particular component or a particular group of components relative to one eye, it will be understood by those skilled in the art that similar operations may be performed relative to the other eye or both eyes. For the sake of brevity, such details are not repeated here.

[0205] Although some of the various figures show multiple logical stages in a particular order, stages that are not dependent on order may be reordered and other stages may be combined or decomposed. Although some reordering or other groupings are specifically mentioned, other reorderings or other groupings will be clear to those of ordinary skill in the art, and thus the ordering and groupings presented herein are not an exhaustive list of alternatives. In addition, it should be appreciated that the stages may be implemented in hardware, firmware, software, or any combination thereof.

[0206] For purposes of explanation, the foregoing description has been described with reference to specific embodiments. However, the above illustrative discussion is not intended to be exhaustive. Modifications and variations of the present invention are possible as defined in the appended claims. The embodiments are selected in order to best explain the claims and their practical application principles, thereby enabling others skilled in the art to best use the embodiments with various modifications suitable for the intended specific use.

Claims

1. A display device, comprising: an image source configured to project image light; as well as A display comprising a first optical diffuser and a second optical diffuser, wherein the display is configured to: receiving the image light; diffuse the image light at the first optical diffuser when the image light has a first polarization; as well as diffuse the image light at the second optical diffuser when the image light has a second polarization different from the first polarization; The display is further configured to: When the image light is configured to have the first polarization, outputting a first diffused image light having the first polarization; as well as When the image light is configured to have the second polarization, a second diffused image light having the second polarization is output, wherein: The first optical diffuser includes a first surface and is configured to receive the image light at the first surface; and The first diffuse image light and the second diffuse image light are each output from the first surface; The display device further comprises: a first optical retarder disposed between the first optical diffuser and the second optical diffuser, wherein: Each of the first optical diffuser and the second optical diffuser is configured as: reflectively diffusing light having said first polarization; and transmitting light having the second polarization; The first optical retarder is configured to receive the image light transmitted through the first optical diffuser; and The first optical retarder may be configured as: converting the image light from the second polarization to the first polarization such that the image light is diffused by the second optical diffuser as second diffused image light having the first polarization; receiving the second diffuse image light; and The second diffuse image light is converted from the first polarization to the second polarization such that the second diffuse image light is transmitted by the first optical diffuser.

2. The display device according to claim 1, wherein the first optical retarder is an active optical retarder, the active optical retarder being configurable to be in any of a first state and a second state, and wherein: In the first state, the first optical retarder is configured to transmit the image light and convert the image light from the second polarization to the first polarization; as well as In the second state, the first optical retarder is configured to transmit the image light. 3 . The display device of claim 2 , wherein the display further comprises one or more third optical diffusers, the one or more third optical diffusers being disposed between the first optical diffuser and the second optical diffuser.

4. The display device according to claim 3, wherein the display further comprises: one or more second optical retarders, each of the one or more second optical retarders corresponding to a corresponding optical diffuser of the one or more third optical diffusers and disposed between the corresponding optical diffuser and the first optical diffuser, wherein Each of the one or more second optical retarders is configured to transmit the image light transmitted through the first optical diffuser toward the second optical diffuser, and transmit the first diffused image light output from the second optical diffuser toward the first optical diffuser.

5. The display device of claim 2, wherein the display further comprises one or more fourth optical diffusers, wherein the second optical diffuser is disposed between the first optical diffuser and the one or more fourth optical diffusers; The display further comprises: and one or more third optical retarders, each of the one or more third optical retarders corresponding to a corresponding optical diffuser of the one or more fourth optical diffusers and disposed between the corresponding optical diffuser of the one or more fourth optical diffusers and the second optical diffuser.

6. A display device according to any one of the preceding claims, wherein the image source comprises: a projector configured to output image light having an initial polarization; a second switchable optical retarder configured to receive the image light having the initial polarization and configurable to be in a first state or a second state, wherein When the second switchable optical retarder is in the first state, the image light output from the image source is configured to have the first polarization; as well as When the second switchable optical retarder is in the second state, the image light output from the image source is configured to have the second polarization; and a polarization-sensitive optical element, configured to: projecting the image light in a first direction toward the first optical diffuser when the image light is configured to have the first polarization; as well as when the image light is configured to have the second polarization, projecting the image light in a second direction toward the second optical diffuser, Wherein the second switchable optical delay device is arranged between the projector and the polarization-sensitive optical element.

7. The display device according to any one of claims 1 to 5, wherein: The first optical diffuser and the second optical diffuser have a same optical axis; and The image source is located at an off-axis position relative to the optical axis.

8. The display device according to claim 6, wherein: The first optical diffuser and the second optical diffuser have a same optical axis; and The image source is located at an off-axis position relative to the optical axis.

9. The display device of claim 7, wherein the first optical diffuser is spaced apart from the second optical diffuser.

10. The display apparatus of claim 8, wherein the first optical diffuser is spaced apart from the second optical diffuser.

11. The display device of claim 1 , wherein each of the first optical diffuser and the second optical diffuser is configured to diffuse first light having the first polarization and transmit second light having the second polarization; wherein each of the first optical diffuser and the second optical diffuser comprises a polarization-sensitive hologram; in: The first light includes a third light within a first wavelength range and a fourth light within a second wavelength range; as well as The respective optical diffusers of the first optical diffuser and the second optical diffuser include: a first optical surface; a second optical surface; a third optical surface; first optically anisotropic molecules arranged to diffuse the third light and disposed between the first optical surface and the second optical surface; and second optically anisotropic molecules arranged to diffuse the fourth light and disposed between the second optical surface and the third optical surface; in: The first light includes fifth light within a first incident angle range and sixth light within a second incident angle range; and The respective optical diffusers of the first optical diffuser and the second optical diffuser include: a first optical surface; a second optical surface; a third optical surface; first optically anisotropic molecules arranged to diffuse the fifth light and disposed between the first optical surface and the second optical surface; and Second optically anisotropic molecules are arranged to diffuse the sixth light and are disposed between the second optical surface and the third optical surface.

12. The display device according to claim 11, further comprising: a first switchable optical retarder configured to receive any of the first diffuse image light and the second diffuse image light and output a third diffuse image light, wherein: The first switchable optical retarder may be configured to be in a third state when the image light has the first polarization, or in a fourth state when the image light has the second polarization; and the third diffuse image light having a third polarization regardless of whether the first switchable optical retarder is in the third state or in the fourth state; and a lens assembly configured to: receiving the third diffuse image light output from the first switchable optical retarder, and focusing the third diffuse image light at a first optical power; and Light having a fourth polarization different from the third polarization is transmitted at a second optical power different from the first optical power, wherein the first switchable optical retarder is disposed between the display and the lens assembly.

13. The display device according to claim 12, wherein: The display is configured to transmit a portion of ambient light incident on the display; and The lens assembly is configured to transmit the portion of the ambient light at the second optical power.

14. The display device of claim 13, wherein a respective one of the first optical diffuser and the second optical diffuser comprises: a first optical surface; a second optical surface, opposite to the first optical surface; as well as optically anisotropic molecules disposed between the first optical surface and the second optical surface and arranged such that the corresponding optical diffuser is configured as: diffusing the first light having the first polarization; and The second light having the second polarization is transmitted.

15. A method for displaying an image, comprising: providing image light from an image source; receiving the image light at a first optical diffuser; When the image light received at the first optical diffuser has a first polarization, diffusing the image light at the first optical diffuser to output first diffused image light, the first diffused image light having the first polarization; as well as When the image light received at the first optical diffuser has a second polarization different from the first polarization: transmitting the image light through the first optical diffuser; converting the image light from the second polarization to the first polarization; diffusing the image light having the first polarization at a second optical diffuser to output second diffused image light, the second diffused image light having the first polarization; converting the second diffuse image light from the first polarization to the second polarization; as well as The second diffuse image light having the second polarization is transmitted through the first optical diffuser. 16 . The method of claim 15 , wherein each of the first optical diffuser and the second optical diffuser is configured to diffuse light having the first polarization and transmit light having the second polarization.

Images