Field-of-view-based optical correction using spatially varying polarizers

Abstract

An optical system is provided. The optical system includes a gaze tracker operable to track a user's gaze and output data representative of the gaze, and a correction portion including a plurality of spatially varying polarizers. A first one of the spatially varying polarizers includes a first control input configured to receive a first control signal indicating whether the first polarizer should be active or inactive. When active, the first polarizer provides a first optical correction to light passing therethrough at a location corresponding to a first region of the virtual image. The optical system includes a controller configured to receive the data representative of the gaze, determine whether to apply the first optical correction to the light based on the gaze, and, in response to determining to apply the first optical correction to the light, output a first control signal indicating that the first polarizer should be active.

Description

[Technical Field]

[0001] The present disclosure relates to an optical correction system that uses a spatially varying polarizer to perform field-based optical correction. [Background technology]

[0002] A head-mounted display device (HMD) is a display device worn on a user's head and has one or more display units for presenting visual content to the user. HMDs are becoming increasingly popular for providing virtual reality (VR) or augmented reality (AR) experiences or for facilitating gaming or the presentation of audiovisual media. The display units are generally miniaturized and may include, for example, CRT, LCD, liquid crystal on silicon (ELCOS), or OLED technology. Some HMDs are binocular, capable of displaying a different image to each eye. This capability is used to display stereoscopic images for a more immersive user experience.

[0003] Conventional HMDs do not take into account the user's viewing angle or field of view: Conventional HMDs display visual content to the user without adapting the virtual light to the user's viewing angle or field of view. Summary of the Invention

[0004] A head-mounted display can be summarized as including a virtual image display unit and an optical system for modifying the virtual image light. The optical system can modify the virtual image light to enhance the user's experience or visibility or improve the angular resolution of the virtual image light. The optical system can perform optical correction to modify the focal length of the virtual image light or sharpen the virtual image light. Specifically, the optical system can target, modify, or act on a specific portion of the virtual image light that the user is viewing or gazing at. That portion of the virtual image light may be within the user's current field of view. Thus, the optical correction can be localized to that portion of the virtual image light.

[0005] The optical correction performed by the optical system can be based on the angle or direction of the user's gaze or the user's field of view, which can be detected, for example, by a gaze tracker in the head-mounted display. The optical system can include a left optical subsystem and a right optical subsystem operable to modify virtual image light received from the virtual image representation to correct for left-eye viewing and right-eye viewing, respectively.

[0006] The optical system includes one or more spatially varying polarizers, each operable to be activated (on) or deactivated (off) based on a controller input. The spatially varying polarizers can be formed from multi-twist retarders (MTRs) and customized to provide precise retardation levels within a single thin film. The spatially varying polarizers can be configured to refract (depending on the refractive index) or diffract (depending on the diffraction pattern) light passing through them, acting as corrective optics. The spatially varying polarizers can be formed as lenses through which polarization is oriented and have electrically controllable focal lengths to focus and collimate the passing light. Due to their spatially varying properties, the multi-twist retarders provide switchable, localized optical correction. This localized optical correction can affect portions of the virtual image light that fall within the user's current field of view. The localized optical correction can affect portions of the virtual image light that fall within the user's current field of view differently from other portions of the virtual image light that are outside the user's current field of view, allowing for optimization of the optical correction within the current field of view.

[0007] Each spatially varying polarizer can be formed to have, among other things, diffraction pattern, light collimation, focusing, or aberration correction properties that affect light passing through that spatially varying polarizer. A subset of two or more spatially varying polarizers can, in combination, have particular diffraction, light collimation, focusing, or aberration correction properties that affect light passing through that subset.

[0008] The spatially varying polarizers are switchable between on and off states. The controller can switch individual spatially varying polarizers, a subset of the spatially varying polarizers, or all available spatially varying polarizers on or off to achieve and implement the corresponding optical correction. The controller can switch various spatially varying polarizers between on and off states to switch between different available optical corrections for different portions of the virtual image. During viewing, the controller receives an indication of the user's gaze from a gaze tracker or other source. As the user's gaze changes, shifting from one region to another, the controller switches the spatially varying polarizers to achieve localized optical correction for portions of the virtual image light that are within the user's current field of view.

[0009] The optical system can be summarized as comprising: a gaze tracker operable to track a user's gaze and output data representative of the gaze; a correction portion having a plurality of spatially varying polarizers, wherein a first spatially varying polarizer of the plurality of spatially varying polarizers includes a first control input configured to receive a first control signal of a plurality of control signals indicating whether the first spatially varying polarizer should be active or inactive, and wherein the correction portion, when the first spatially varying polarizer is active, is operable to provide a first optical correction to light passing through the correction portion at a position corresponding to a first region of a plurality of regions of a virtual image; and a controller configured to receive the data representative of the user's gaze, determine based on the gaze whether the first optical correction should be applied to the light passing through the position corresponding to the first region within the correction portion, and output the first control signal indicating that the first spatially varying polarizer should be active in response to determining to apply the first optical correction to the light passing through the position corresponding to the first region within the correction portion. The first region of the plurality of regions of the virtual image may be within a field of view of the user's gaze. The controller may be configured to determine, based on the data representing the user's gaze, that the gaze has changed and to determine to perform a second optical correction by a second space-varying polarizer of the plurality of space-varying polarizers on light passing through a position in the correction portion corresponding to a second region of the plurality of regions of the virtual image. The second space-varying polarizer of the plurality of space-varying polarizers may have a second control input configured to receive a second control signal of the plurality of control signals indicating whether the second space-varying polarizer should be active or inactive, and the controller may be configured to output the second control signal indicating that the second space-varying polarizer should be active in response to determining to perform the second optical correction on the light passing through the position in the correction portion corresponding to the second region.The controller may be configured to output the first control signal indicating that the first spatially varying polarizer should be inactive in response to determining to perform the second optical correction on the light passing through the position corresponding to the second region within the correction portion. The first and second spatially varying polarizers may be in a stacked configuration such that the light passing through the correction portion passes through the first spatially varying polarizer before entering the second spatially varying polarizer. Providing the first optical correction may include performing diffraction according to a diffraction pattern, light collimation, focusing, image sharpening, angular resolution modification, focal length modification, or aberration correction. Any of the spatially varying polarizers may include a multi-twist retarder (MTR).

[0010] The head mounted display system includes an optical system having a support structure, a display, a gaze tracker operable to track a user's gaze and output data representative of the gaze, and first and second optical subsystems, each of the first and second optical subsystems including a correction portion including a plurality of spatially varying polarizers, a first spatially varying polarizer of the plurality of spatially varying polarizers including a first control input configured to receive a first control signal of a plurality of control signals indicating whether the first spatially varying polarizer should be active or inactive, and when the first spatially varying polarizer is active, a position corresponding to a first region of a plurality of regions of a virtual image is displayed. and a controller configured to receive, for each of the first and second optical subsystems, the data representing the gaze of the user, determine whether to apply the first optical correction to the light passing through the position in the correction portion corresponding to the first region based on the gaze, and output the first control signal indicating that the first spatially varying polarizer should be active in response to determining to apply the first optical correction to the light passing through the position in the correction portion corresponding to the first region. For each of the first and second optical subsystems, the first region of the plurality of regions of the virtual image may be within a field of view of the gaze of the user. For each of the first and second optical subsystems, the controller may be configured to determine that the gaze has changed based on the data representing the gaze and to decide to perform a second optical correction by a second spatially varying polarizer of the plurality of spatially varying polarizers on light passing through a position in the correction portion corresponding to a second region of the plurality of regions of the virtual image.For each of the first and second optical subsystems, the second spatially varying polarizer of the plurality of spatially varying polarizers can have a second control input configured to receive a second control signal of the plurality of control signals indicating whether the second spatially varying polarizer should be active or inactive, and for each of the first and second optical subsystems, the controller can be configured to output the second control signal indicating that the second spatially varying polarizer should be active in response to determining to perform the second optical correction on the light passing through the position corresponding to the second region in the correction portion. For each of the first and second optical subsystems, the controller can be configured to output the first control signal indicating that the first spatially varying polarizer should be inactive in response to determining to perform the second optical correction on the light passing through the position corresponding to the second region in the correction portion. For each of the first and second optical subsystems, the first and second spatially varying polarizers may be in a stacked configuration such that the light passing through the correction portion passes through the first spatially varying polarizer before entering the second spatially varying polarizer. For each of the first and second optical subsystems, providing the first optical correction may include performing diffraction according to a diffraction pattern, light collimation, focusing, image sharpening, angular resolution modification, focal length modification, or aberration correction. For each of the first and second optical subsystems, any spatially varying polarizer of the plurality of spatially varying polarizers may include a multi-twist retarder (MTR). [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is an overhead plan view of a head-mounted display having an optical system according to one or more implementations.

[0012] [Figure 2]FIG. 2 is a diagram of an optical subsystem of the optical system of the head-mounted display of FIG. 1.

[0013] [Figure 3] FIG. 2 is a perspective view of the exterior of the head-mounted display of FIG. 1. [Figure 4] FIG. 1 is a schematic block diagram of a head-mounted display.

[0014] [Figure 5] FIG. 5 is a diagram of a correction portion coupled to a controller described with reference to FIG. 4.

[0015] [Figure 6] FIG. 1 illustrates an example of field-based optical correction performed by multiple spatially varying polarizers.

[0016] [Figure 7] FIG. 10 is a diagram of an example surface phase map for a spatially varying polarizer in accordance with one described non-limiting implementation.

[0017] [Figure 8] FIG. 10 is a diagram of another example surface phase map for a spatially varying polarizer in accordance with one described non-limiting implementation. DETAILED DESCRIPTION OF THE INVENTION

[0018] In the following description, certain specific details are set forth to provide a thorough understanding of the various disclosed implementations. However, those skilled in the art will recognize that the implementations may be practiced without one or more of these specific details, or with other methods, components, materials, etc. In other instances, well-known structures related to computer systems, server computers, and / or communication networks are not shown or described in detail to avoid unnecessarily obscuring the description of the implementations.

[0019] Unless the context requires otherwise, throughout the following specification and claims, the word "comprising" is synonymous with "including" and is inclusive or open-ended (i.e., does not exclude additional, unrecited elements or method acts). As used herein, unless otherwise indicated or contradicted by context, reference to the term "set" (e.g., "set of items") is to be construed as a non-empty set that includes one or more members or instances.

[0020] Throughout this specification, the reference to "one implementation" or "an implementation" means that a particular feature, structure, or characteristic described in connection with that implementation is included in at least one implementation. Thus, the appearances of the phrase "in one implementation" or "in an implementation" in various places throughout this specification are not necessarily all referring to the same implementation. Furthermore, particular features, structures, or characteristics may be combined in any suitable manner in one or more implementations.

[0021] As used herein and in the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. It should also be noted that the term "or" is generally used to include "and / or" unless the context clearly dictates otherwise.

[0022] The headings and abstracts of the disclosure provided herein are for convenience only and do not interpret the scope or meaning of the implementations.

[0023] FIG. 1 illustrates an overhead plan view of a head-mounted display device (HMD) 100 according to one or more embodiments. The HMD 100 is configured to present virtual reality (VR) to a user 104, such as through corresponding video presented at a display rate such as 30 frames (or images) per second or 90 frames per second; other embodiments of similar systems can present augmented reality displays to the user 104. The HMD 100 provides corrected virtual image light 102 to the left eye 105l and right eye 105r of the user 104. The HMD 100 includes one or more virtual image display units 106 mounted on or within a frame 108. The virtual image display units 106 generate virtual image light 102 for allowing the user to perceive visual content. The HMD 100 may further include a set of left and right lenses 107l and 107r provided on the output side of the virtual image display units 106. After virtual image light 102 is emitted from virtual image display unit 106, set of left and right lenses 107l and set of 107r can focus, collimate, or otherwise modify virtual image light 102. Set of left and right lenses 107l and set of 107r can include, for example, Fresnel lenses that refract or collimate virtual image light 102.

[0024] HMD 100 also includes optical system 112 having selectively variable optical properties to compensate for one or more visual conditions of the user. For example, optical system 112 is selectively adjustable to locally compensate for light. Virtual image light 102 emitted from virtual image display unit 106 travels along optical path 126 within optical system 112, which modifies virtual image light 102 according to the optical properties of optical system 112 and emits compensated virtual image light 114 to each of the user's left and right eyes 105l and 105r, respectively.

[0025] The frame 108 is a mounting structure for supporting the HMD 100 on the head of the user 104. The frame 108 includes a body 116 having a front portion 118 and a viewing portion 120 opposite the front portion 118 to position the frame 108 in front of the user's eyes 105l and 105r, which view the generated visual content. The HMD 100 includes one or more support structures for selectively mounting the HMD 100 on the user's head. For example, the HMD 100 of FIG. 1 includes left and right temples 122l and 122r that rest over the user's 104's left and right ears 124l and 124r, respectively. In some embodiments, the HMD 100 may include other support structures, such as a strap connected to the body 116 and wrapped around the back of the user's 104's head. A nose assembly (not shown) of the HMD 100 can support the body 116 over the user's 104's nose. The frame 108 can be shaped and sized to position the optical system 112 in front of one of the user's eyes 105l and 105r. While the frame 108 is shown for illustrative purposes as being similar to eyeglasses for simplicity, it should be understood that in practice more elaborate structures (e.g., goggles, integrated headbands, helmets, straps, etc.) can be used to support and position the HMD 100 on the head of the user 104.

[0026] The virtual image display unit 106 generates virtual image light 102 that is transmitted through and selectively modified by the optical system 112. The virtual image display unit 106 includes a left display unit 106l for generating image light for presentation to the left eye 105l and a right display unit 106r for generating image light for presentation to the right eye 105r. The virtual image display unit 106 may include a liquid crystal display (LCD), a light emitting diode (LED), a cathode ray tube (CRT), a liquid crystal on silicon (ELCOS), or other light emitting technology for generating the virtual image light 102. The virtual image display unit 106 of the embodiment shown in FIG. 1 is located in the front portion of the HMD 100 and emits light in a rearward direction toward the eyes of the user 104. In some embodiments, virtual image display unit 106 can include wavelengths that direct (e.g., reflect, refract) virtual image light 102 toward eye 105l or 105r, such that the light emitting elements of virtual image display unit 106 are not directly in front of eyes 105l and 105r for perception of visual content by user 104. In some embodiments, front portion 118 of body 116 can be at least partially transparent, such that user 104 can perceive external content to provide an augmented reality experience.

[0027] The HMD 100 includes a gaze tracker 127 configured to track the gaze (or direction) of the user 104 or the user's eyes 105l, 105r. While the gaze tracker 127 is illustrated as an internal element of the HMD 100, in alternative embodiments, the gaze tracker 127 may be an external sensor. Furthermore, the gaze tracker 127 may perform gaze or pupil tracking separately for each of the eyes 105l and 105r, or track the position or orientation of the user's 104's head (e.g., as part of head tracking). Furthermore, the gaze tracker 127 may track various other types of movements and positions of the user's body.

[0028] The gaze tracker 127 can output data representing the gaze of the user 104. This data can indicate the portion (location or area) of the viewing portion 120 to which the user 104 is directing his or her gaze. This portion (location or area) can be the center of the viewing portion 120, one of the quadrants of the viewing portion 120, or any other area of ​​the viewing portion 120. The data representing the gaze of the user 104 can be an angle or a coordinate (Cartesian or polar) to which the user's gaze is directed.

[0029] While in some embodiments the described techniques can be used with a display system similar to that shown in FIG. 1 , in other embodiments other types of display systems can be used, including those using a single optical lens and display device or multiple such optical lenses and display devices. Non-exclusive examples of other such devices include cameras, telescopes, microscopes, binoculars, spotting scopes, surveying scopes, etc. Additionally, the described techniques can be used with a wide variety of display panels or other display devices that emit light to form images, which are viewed by a user or users through one or more optical lenses. In other embodiments, a user can view one or more images through one or more optical lenses that are produced in a manner other than through a display panel (such as an image produced on a surface that partially or wholly reflects light from other light sources).

[0030] The virtual image light 102 may include multiple light rays from each of the virtual image display units 106 traveling along an optical path 126 in the optical system 112 toward the viewing portion 120. The optical system 112 modifies some or all of the multiple light rays to provide corrected virtual image light 114. The optical system 112 includes one or more optical subsystems 130 for modifying the virtual image light 102. The multiple optical subsystems 130 include a left optical subsystem 1301 for modifying the virtual image light 102 for the left eye 1051 and a right optical subsystem 130r for modifying the virtual image light 102 for the right eye 105r, although a single optical subsystem 130 may be used to modify the virtual image light 102 for both eyes 1051, 105r together. Each of the left and right optical subsystems 130l and 130r may be independently adjustable to enhance the viewing experience of the user 104 or to correct for visual deficiencies or defects in the left eye 105l and right eye 105r, respectively.

[0031] FIG. 2 shows a diagram 200 of the optical subsystem 130 (e.g., optical subsystem 130l or 130r) of FIG. 1 in accordance with one or more embodiments. The optical subsystem 130 includes a receiving portion 202 for receiving initial virtual image light 204 corresponding to the virtual image light 102 for a single eye and an output portion 206 for outputting corrected virtual image light 208. The initial virtual image light 204 may include multiple light rays 205, each having a specific set of attributes (e.g., color, direction, brightness) for causing the user 104 to perceive visual content. Any of the multiple light rays 205 corresponds to a position on the initial virtual image (represented by the initial virtual image light 204). Any of the light rays 205 (or light) may be incident on the receiving portion 202 at a position that matches, coincides with, or corresponds to the position on the initial virtual image.

[0032] Optical subsystem 130 further comprises correction portion 210 having one or more spatially varying polarizers 211 as described herein. Correction portion 210 corrects initial virtual image light 204 and emits corrected virtual image light 208. At any one time, correction portion 210 may correct a portion of initial virtual image light 204. Correction portion 210 may correct different portions of initial virtual image light 204 in different ways. Correction portion 210 may correct one or more portions of initial virtual image light 204 and may not apply optical correction to one or more other portions of initial virtual image light 204.

[0033] It should be noted that although three spatially varying polarizers 211 (first, second, and third spatially varying polarizers 211a, 211b, and 211c) are shown in FIG. 2, the optical subsystem 130 may include any number of spatially varying polarizers 211.

[0034] Each spatially varying polarizer 211 a, 211 b, 211 c has a respective input 212 a, 212 b, 212 c operable to receive a respective control signal indicating whether the spatially varying polarizer 211 a, 211 b, 211 c should be on or off. The control signal can have a first state indicating that the spatially varying polarizer 211 should be on and a second state indicating that the spatially varying polarizer 211 should be off. The inputs 212 can be coupled to, and the control signal can be received from, a controller (not shown in FIG. 2 ) as described herein.

[0035] The spatially varying polarizer 211 can be formed of a multi-twist retarder (MTR), a retardation film similar to a waveplate that provides customized, precise broadband, narrowband, or multi-band retardation levels within a single thin film. More specifically, an MTR comprises two or more twisted liquid crystal (LC) layers on a single substrate with a single alignment layer. The subsequent LC layer is directly aligned with the previous layer, allowing for simple fabrication, automatic layer-to-layer alignment, and resulting in a monolithic film with a continuously varying optic axis.

[0036] Due to its spatially varying properties, the multi-twist retarder provides localized optical correction that can affect portions of the virtual image light (e.g., the initial virtual image light) that are within the user's current field of view. The localized optical correction can affect portions of the virtual image light that are within the user's current field of view differently than other portions of the virtual image light that are outside the user's current field of view.

[0037] The spatially varying polarizer 211 can comprise a wave retarder formed of a birefringent material. Birefringence is a property of a material that has a refractive index that depends on the polarization and propagation direction of the light. The wave retarder changes the polarization state or phase of light traveling through it. The wave retarder can have a slow axis (or non-ordinary axis) and a fast axis (ordinary axis). As polarized light travels through the wave retarder, light along the fast axis travels faster than light along the slow axis.

[0038] The spatial variation polarizers 211 can be configured to act as corrective optics. The birefringent material of the spatial variation polarizers 211 can be configured to cause light passing through them to undergo refraction (e.g., according to the refractive index). Each spatial variation polarizer 211 can have a diffraction pattern. The spatial variation polarizers 211 can be formed as lenses through which polarized light is oriented and can have an electrically controllable focal length. Furthermore, the spatial variation polarizers 211 can perform collimation on the light passing through them.

[0039] As used herein, optical correction includes introducing an optical change or modification into light passing through or traversing correction portion 210. As used herein, correction with respect to optical modification is not intended to mean correction for pre-correction light or image deficiencies or light or image deficiencies. Optical correction can be used to enhance or improve image visualization for a particular set of circumstances or to meet particular user experience criteria or metrics.

[0040] One or more spatially varying polarizers 211 in the correction section 210 can operate individually, collectively, or in subsets as electrically controlled correction optics. Each spatially varying polarizer 211 can be formed to have, among other things, diffraction pattern, light collimation, focusing, or aberration correction properties that affect light passing through it. Furthermore, a subset of two or more of the available spatially varying polarizers 211 can, in combination, have, among other things, specific diffraction, light collimation, focusing, or aberration correction properties that affect light passing through it. When a subset is activated (or switched on) and the other available spatially varying polarizers 211 are deactivated (or switched off), the subset can affect light passing through it according to the specific properties of the subset.

[0041] Each spatial variation polarizer 211a, 211b, 211c can be configured to perform a specific optical correction as an optical component. Additionally or alternatively, two or more spatial variation polarizers 211 can be configured to perform a specific optical correction as an optical component in combination. The spatial variation polarizers 211a, 211b, 211c can be layered or stacked, with multiple light beams 205 passing from the first spatial variation polarizer 211a to the second spatial variation polarizer 211b and then to the third spatial variation polarizer 211c. The first spatial variation polarizer 211a and the second spatial variation polarizer 211b are each configured to jointly perform a desired optical correction. The first spatial variation polarizer 211a can be configured to perform a first optical correction on light 205 incident on the first spatial variation polarizer 211a. The second spatially varying polarizer 211b can be configured to perform a second optical correction on light (after being corrected with the first optical correction) incident on the second spatially varying polarizer 211b, the combination of the first and second optical corrections jointly achieving the desired optical correction.

[0042] Continuing with this example, the third spatially varying polarizer 211c can be turned off, such that it does not obstruct or interfere with the desired optical correction performed by the first spatially varying polarizer 211a and the second spatially varying polarizer 211b. When turned off, the third spatially varying polarizer 211c may not perform any optical correction itself. Alternatively, when turned off, the third spatially varying polarizer 211c may perform the third optical correction. In this case, the first and second optical corrections can be adjusted to cancel out the third optical correction (and reverse the effect of the third optical correction) to achieve the desired optical correction.

[0043] The optical corrections can be performed spatially non-uniformly on the initial virtual image light 204. Spatial non-uniformity includes applying optical corrections differently or non-uniformly to different portions of the initial virtual image light 204. Spatial non-uniformity also includes performing different types of optical corrections on different portions of the initial virtual image light 204 or at different locations on the initial virtual image light 204. For example, the first optical correction of the first spatially varying polarizer 211a can focus a first portion (e.g., the center) of the initial virtual image light 204 and defocus a second portion (e.g., the periphery or edge) of the initial virtual image light 204. It should be understood that the terms “defocused” or “out of focus” can be relative terms, meaning that focus on such portions may not be optimal relative to the “focused” portion. Continuing with this example, a second optical correction of second spatially varying polarizer 211 a may optically correct the center of initial virtual image light 204 according to a user's prescription, but may not perform optical correction according to a user's prescription on the periphery or edges of initial virtual image light 204. An optical correction may perform sharpening on a portion of initial virtual image light 204 and not perform sharpening on another portion of initial virtual image light 204.

[0044] 3 illustrates a housing 300 for an HMD 100 according to one or more embodiments. The HMD 100 includes a set of straps 302 attached to the body 116. The set of straps 302 can be used to selectively securely attach the HMD 100 to the head of the user 104 for viewing visual content. The body 116 can include a control panel 304 for controlling various aspects of the HMD 100. The control panel 304 can include one or more input devices for controlling the optical properties of the optical system 112 and correcting the visual content. The visual content can be corrected to improve the experience of the user 104 and / or correct for the visual conditions of the user 104 (e.g., myopia, hyperopia, astigmatism).

[0045] The input device may be an electrical device electrically coupled to the controller and configured to instruct the controller to configure the optical correction performed by the correction portion 210 and one or more spatially varying polarizers 211 of the correction portion 210. As an example, in response to interaction by the user 104, the input device can cause an electrical signal to be sent to the controller, which in response sends one or more control signals to each of the spatially varying polarizers 211 a, 211 b, 211 c to adjust the optical correction performed by the correction portion 210. Non-limiting examples of electrical input devices for the control panel 304 include a keypad having a set of keys for providing alphanumeric input or for navigating a menu, or a dial or knob electrically coupled to the controller. The housing 300 can include a display 306 for displaying information about the HMD 100, such as the current optical settings of the optical system 112. In some embodiments, the display 306 can be a touchscreen input device that the user 104 can interact with to control the optical system 112.

[0046] In some embodiments, a user can adjust the optical settings of optical system 112 in relation to visual content presented by virtual image display unit 106. For example, a user wearing HMD 100 can adjust the optical settings by interacting with control panel 304 or other input device (e.g., handheld controller, mouse, keyboard) according to menus or other visual content displayed by virtual image display unit 106. As one example, the user can navigate menus and provide user input via control panel 304 or other input device, and in response to the user input, the optical settings of optical system 112 are changed. As another example, HMD 100 can adjust the optical settings of optical system 112 in real time in response to user input about the visual content perceived by user 104. A user can initiate a vision test on HMD 100, which causes virtual image display unit 106 to display visual content, such as a test pattern, and the user is prompted to provide input about the clarity of the visual content. As a result of receiving this input, the HMD 100 can automatically adjust the optical settings of the optical system 112 to improve the clarity of the visual content, thereby improving the experience of the user 104.

[0047] FIG. 4 is a block diagram 400 illustrating the interconnection of various parts of an HMD 100 according to one or more embodiments. The HMD 100 includes a controller 402. The controller 402 comprises one or more processors 404 and a memory 406 that stores a set of instructions that, upon execution by the one or more processors 404, cause the HMD 100 to perform one or more operations described herein. As a non-limiting illustrative example, the memory 406 may include read-only memory (ROM) and random-access memory (RAM) and may be in the form of solid-state memory or a hard disk drive. The HMD 100 also includes a communication interface 408 electrically coupled to the controller 402 for communicating with external devices. The communication interface 408 may include one or more wireless transceivers, such as a Wi-Fi transceiver, a cellular transceiver, a Bluetooth transceiver, or the like, for wirelessly communicating with external devices, such as a network router or a computing device (e.g., a laptop, desktop, tablet, mobile device). The communication interface 408 may also include a wired communication port, such as a Universal Serial Bus port or a network interface port, for wired communication with external devices.

[0048] The HMD 100 may include a set of input devices 410 electrically coupled to the controller 402 for providing user input to the HMD 100. One or more of the input devices 410 of the set of input devices 410 may be provided on the housing 300 of the HMD 100 (e.g., as part of the control panel 304). The controller 402 may also be electrically coupled to and configured to control the virtual image display unit 106 and / or the display 306 (if included). In some embodiments, the controller 402 may include one or more graphics processing units for generating the virtual image light 102 via the virtual image display unit 106.

[0049] The controller 402 is electrically coupled to the optical system 112 and configured to control the optical system 112 to adjust its optical properties as described herein. Specifically, the controller 402 is electrically coupled to and configured to control the correction portion 412 of the left optical subsystem 130l and the correction portion 416 of the right optical subsystem 130r.

[0050] Each correction portion 412, 416 can be configured as described herein with reference to FIG. 2 . The controller 402 is electrically coupled to the correction portions 412, 416 to control the spatially varying polarizers 211 of the correction portions. Specifically, the controller 402 sends signals (e.g., control signals) to the correction portions 412, 416 to cause each correction portion 412, 416 to perform optical correction by switching its spatially varying polarizer 211 on and off. As described above, the correction portions 412, 416 can be controlled to modify their optical properties. The controller 402 can send the signals in response to receiving input. For example, the controller 402 may adjust the optical properties in response to receiving input from the input device 410. As another example, the controller 402 can adjust the optical properties in response to receiving input via the communication interface 408.

[0051] The input received by the controller 402 may have a particular format. The input may indicate a prescription for the right eye and / or a prescription for the left eye. For each eye, the input may indicate the power or sphere (sometimes referred to as SPH or S), cylinder (sometimes referred to as CYL or C), and / or axis (typically 0 to 180). The input may include inputs for the left optical subsystem 130l and the right optical subsystem 130r.

[0052] In at least some implementations, the HMD 100 includes a gaze tracker 127 configured to track the gaze (or direction) of the user 104 or the user's eyes 105l, 105r. The gaze tracker 127 can perform gaze or pupil tracking separately for each of the eyes 105l and 105r, or can track the position or orientation of the user's 104's head (e.g., as part of head tracking). Additionally, the gaze tracker 127 can track various other types of movements and positions of the user's body. The gaze tracker 127 can output data representing the gaze of the user 104. This data can indicate a portion (location or area) of the display 306 or viewing portion 120 to which the user 104 is directing their gaze. This portion (location or area) can be the center, one of the quadrants, or any other area. The data representing the user's 104's gaze can be an angle or coordinate (Cartesian or polar) to which the user's gaze is directed.

[0053] Adjustments to the optical settings of the optical subsystem 112 can be adjusted in real time based on data representing the gaze of the user 104 and / or through feedback provided by the user 104. The controller 402 can initiate a test to determine adjustments to be made to the optical settings of the optical system 112. The test can include causing the virtual image display unit 106 to display particular visual content, such as a test pattern or a detailed visual image, and prompting the user to provide feedback via the input device 410 or the control panel 304. The user 104 may provide feedback indicating that some aspects of the visual content (e.g., text, images) appear blurry. The controller 402 can adjust the optical settings of the optical system 112 and ask the user 104 whether the adjustments improved the clarity of those aspects of the visual content. This process can be iterative and can be repeated until the user 104 is satisfied with the clarity of the visual content. The test can be performed in response to receiving user input from the user 104 via the input device 410 or the control panel 304. The controller 402 may instruct the user 104 to change their gaze, apply localized optical corrections, and prompt the user to provide feedback via the input device 410 or the control panel 304.

[0054] Input via communication interface 408 may be provided by a device (e.g., laptop, desktop, mobile device, controller) as a result of user interaction. Such a computing device may include a set of instructions (e.g., an application, a program) with which a user can interact to cause the computing device to send a communication including information indicating or representing optical properties to modify virtual image light 102 (e.g., to correct for the visual conditions of user 104). A user may provide input to input device 410 or the computing device as a prescription provided by a medical professional, which may have a predetermined format as described above.

[0055] The controller 402 can determine signals to be sent to the correction portions 412, 416 in response to receiving inputs from the input device 410 or the communication interface 408. One or more of the processors 404 can access a data structure stored, for example, in the memory 406, that indicates the control signals to be sent to the corresponding correction portions 412, 416. This data structure can be an array, look-up table, or other reference structure in which input data is associated with the corresponding output (i.e., control signal) to be sent. In some implementations, the controller 402 can store information in the memory 406 that indicates the current state of the optical system 112, from which the controller 402 can determine adjustments to satisfy the received inputs.

[0056] In one embodiment, the spatially varying polarizer 211 can be configured using advanced knowledge of the prescription or medical condition of the user 104 or a set of potential users of the HMD 100, allowing the spatially varying polarizer 211 to be tailored to the user 104 or a set of potential users. In this case, the HMD 100 can be customized for the user 104 or a set of potential users, who may be the user's friends or the user's family. For example, each spatially varying polarizer 211 can be configured to optically correct for a particular user of the set of potential users. During use, the controller 402 can switch to a particular spatially varying polarizer 211 depending on who the user of the HMD 100 is.

[0057] The spatially varying polarizer 211 can be configured to provide optical correction within the range of the user's current prescription. If the user's vision changes or deteriorates over time, the controller 402 of the HMD 100 customized for the user 104 can adjust the optical correction within that range to fine-tune the optical correction and provide optical correction that better suits the user's changed prescription. The ability to change the optical correction provided by the correction portions 412, 416 described herein allows the optical correction to be adapted to new, foreseen or predictable optical correction needs. For example, localized or region-based optical focus can be implemented based on the user's current prescription and foreseen or predictable changes in prescription.

[0058] In some embodiments, the HMD 100 may be configured to detect the visual conditions of the user's eyes 105l and 105r and automatically adjust the optical system 112 as a result of the detection. In such embodiments, the HMD 100 may include one or more sensors 424 that detect information about the user's eyes 105l and 105r and provide measurements to the controller 402, which adjusts the optical system 112 accordingly. The HMD 100 may also include one or more lighting elements 426 coupled to the controller 402 and used in conjunction with the sensors 424 to obtain information. The lighting elements 426 may emit light at some angle and with particular properties (e.g., frequency, intensity) such that the light is reflected and received by the sensor 424. The sensor 424 may determine information about the user's eyes based on the light detected from the user's eyes. As a result of the information determined about the user's 104's eyes, the controller 402 may appropriately adjust the optical properties of the optical system 112.

[0059] 5 illustrates the correction portion 210 coupled to the controller 402 described with reference to FIG. 4. The controller 402 has a plurality of outputs 214a, 214b, and 214c coupled to a plurality of inputs 212a, 212b, and 212c of a plurality of spatially varying polarizers 211a, 211b, and 211c, respectively. While the illustrated example shows a three-layer spatially varying polarizer for illustrative purposes, fewer layers (e.g., one, two) or more layers (e.g., five, ten, twenty, etc.) may be used as appropriate in certain applications. The controller 402 sends a control signal via each output 214 operable to activate or deactivate the spatially varying polarizer 211.

[0060] The controller 402 has an input coupled to the output of the gaze tracker 127. The controller 402 receives data from the gaze tracker 127 representing the user's gaze and, based on the data, switches the plurality of spatially varying polarizers 211 between on and off states. The controller 402 can operate the plurality of spatially varying polarizers 211 to perform optical correction on an area where the user 104 directs their gaze and / or on areas outside the user's gaze. As the user's gaze changes over time during a viewing period, the controller 402 can operate the plurality of spatially varying polarizers 211 in a time-division multiplexed manner to change the location where the optical correction is performed so that the optical correction follows the user's gaze.

[0061] Changes can be made in, removed from, or applied to optical corrections performed on areas of the virtual image that were originally outside the user's gaze but are now gazed upon by the user 104. Similarly, changes can be made in, removed from, or applied to optical corrections performed on areas of the virtual image that were originally gazed upon by the user's gaze but are now outside the user's gaze.

[0062] When inactive, the spatially varying polarizer 211 may be optically clear or may only perform an inherent optical correction associated with the material composition of the spatially varying polarizer 211. Various types of materials have optical properties and are operable to alter light. As described herein, the spatially varying polarizer 211 may be formed of two or more twisted liquid crystal layers. The liquid crystal layers of the spatially varying polarizer 211 can perform an inherent optical correction even when turned off. When turned on, the spatially varying polarizer 211 performs the optical correction it is designed to perform.

[0063] The first, second, and third spatially varying polarizers 211a, 211b, and 211c are configured to perform first, second, and third optical corrections. In operation, the controller 402 sends control signals to the spatially varying polarizers 211a, 211b, and 211c to operate the spatially varying polarizers 211a, 211b, and 211c between active and inactive states. For example, to activate the first optical correction and deactivate the second and third optical corrections, the controller 402 sends a control signal to the first spatially varying polarizer 211a to activate the first spatially varying polarizer 211a and sends respective control signals to the second and third spatially varying polarizers 211b and 211c to deactivate the second and third spatially varying polarizers 211b and 211c, respectively. The first optical correction may be a combination of the desired optical correction and optical compensation. The optical compensation can cancel out the inherent optical correction performed by the deactivated second and third spatially varying polarizers 211 b, 211 c. Thus, light exiting the first spatially varying polarizer 211 a and traversing the deactivated second and third spatially varying polarizers 211 b, 211 c has already been cancelled out for the inherent optical correction performed by the deactivated second and third spatially varying polarizers 211 b, 211 c.

[0064] In another example, the controller 402 may send a control signal to the first spatially varying polarizer 211a to deactivate the first spatially varying polarizer 211a, and may send respective control signals to the second and third spatially varying polarizers 211b, 211c to activate the second and third spatially varying polarizers 211b, 211c, respectively. The first optical correction provided by the second and third spatially varying polarizers 211b, 211c is a combination of the second and third optical corrections. The controller 402 selectively switches the spatially varying polarizers 211 between an active state and an inactive state to cause the correction portion 210 to provide the optical correction.

[0065] FIG. 6 illustrates an example of field-based optical correction performed by multiple spatially varying polarizers 211a through 211l. In the example of FIG. 6, the first spatially varying polarizer 211a performs optical correction by focusing a central region (or central portion) of an image (or display) while simultaneously focusing peripheral regions (or peripheral portions) of the image at the top left, top right, bottom left, and bottom right. The optical correction performed by the first spatially varying polarizer 211a for these five regions may be performed separately by the second spatially varying polarizer 211b, the third spatially varying polarizer 211c, the fourth spatially varying polarizer 211d, the fifth spatially varying polarizer 211e, and the sixth spatially varying polarizer 211f, respectively. The second spatially varying polarizer 211b focuses the central region of the image (or display) while not applying optical correction to the top left, top right, bottom left, and bottom right regions. The third spatial variation polarizer 211c puts the top left region out of focus while not focusing the central region or the remaining peripheral regions. The fourth spatial variation polarizer 211d puts the top right region out of focus while not focusing the central region or the remaining peripheral regions. The fifth spatial variation polarizer 211e puts the bottom left region out of focus while not focusing the central region or the remaining peripheral regions. The sixth spatial variation polarizer 211f puts the bottom right region out of focus while not focusing the central region or the remaining peripheral regions.

[0066] Instead of focusing, the seventh, eighth, ninth, tenth, and eleventh spatially varying polarizers 211g, 211h, 211i, 211j, and 211k perform optical correction by sharpening the areas optically corrected by the second, third, fourth, fifth, and sixth spatially varying polarizers 211b, 211c, 211d, 211e, and 211f. The twelfth spatially varying polarizer 211l optically corrects the central portion of the image by changing the angular resolution of that central portion. The twelfth spatially varying polarizer 211l in the example of FIG. 6 does not optically correct other areas of the image.

[0067] The spatially varying polarizer 211 can perform one or more different types of optical correction or the same optical correction on different regions of the image. The controller 402 switches the spatially varying polarizer 211 to achieve various optical effects. For example, as the user's gaze changes, the controller 402 can accordingly switch on the spatially varying polarizer 211 (and switch off other spatially varying polarizers 211) to keep regions within the user's gaze in focus and other regions outside the gaze out of focus. The controller 402 can operate the spatially varying polarizer 211 to keep regions within the user's gaze sharp or to change the angular resolution or focal length of those regions.

[0068] The spatially varying polarizers of the present disclosure can provide spatially varying polarization defined by a surface phase map or a combination of two or more multiplexed surface phase maps. More generally, any linear or nonlinear function can be used to define the surface of one or more of the spatially varying polarizers of the present disclosure to provide a desired function. Figures 7 and 8 show two non-limiting examples of surface phase maps for spatially varying polarizers. In the exemplary surface map 700 of Figure 7, the phase varies concentrically from -0.433 wavelengths to +0.433 wavelengths from the center of the optical component to the periphery. In the exemplary surface map 800 of Figure 8, the phase varies linearly from -1.25E+004 at the bottom of the optical component (as shown) to +1.25E+004 at the apex of the optical component (as shown), each in units of a period of 2π radians. In application, two or more spatially varying polarizers may be stacked. For example, a concentric surface phase map 700 may be multiplexed with a linear phase map 800, etc. Note that while the phase variations in surface maps 700 and 800 are shown in discrete increments for simplicity, in practice the phase may be continuously variable across the surface of the optical component. Furthermore, the particular phase values ​​in surface phase maps 700 and 800 are provided by way of example and should not be considered limiting.

[0069] In at least some implementations, the surface phase map of the spatially varying polarizer can be designed to offset or cancel undesired polarization due to at least one other component of the display system, such as a display source, a lens, etc. In such implementations, a phase profile or phase map of the optical system (e.g., a lens, or a lens and a display source) may first be determined. The determined phase map can then be inverted and applied to the spatially varying polarizer, such that the spatially varying polarizer offsets or cancels undesired effects due to the other components of the optical system.

[0070] The various embodiments described above can be combined to provide further embodiments. These and other modifications can be made to the embodiments in light of the above detailed description. In the following claims, the terms used generally should not be construed to limit the claims to the specific embodiments disclosed in the specification and claims, but should be construed to include all possible embodiments, along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.

Claims

1. a gaze tracker operable to track a user's gaze and output data representative of said gaze; a correction portion having a plurality of spatially varying polarizers, a first of the plurality of spatially varying polarizers including a first control input configured to receive a first control signal of a plurality of control signals indicating whether the first spatially varying polarizer should be active or inactive, the first spatially varying polarizer being operable, when active, to provide a first optical correction to light passing through the correction portion at a location corresponding to a first of a plurality of regions of a virtual image; receiving the data representing the gaze of the user; determining, based on the gaze, whether the first optical correction should be performed on the light passing through the position corresponding to the first region within the correction portion; and outputting the first control signal indicating that the first spatially varying polarizer should be active in response to determining to perform the first optical correction on the light passing through the position corresponding to the first region within the correction portion. and a controller configured to: The optical system is configured such that the controller determines that the user's gaze has changed based on the data representing the user's gaze and decides to perform a second optical correction using a second spatially varying polarizer among the plurality of spatially varying polarizers on light passing through a position within the correction portion corresponding to a second region among the plurality of regions of the virtual image.

2. The first region of the plurality of regions of the virtual image is within the field of view of the gaze of the user.

10. The optical system of claim 1.

3. the second spatially varying polarizer of the plurality of spatially varying polarizers has a second control input configured to receive a second control signal of the plurality of control signals indicating whether the second spatially varying polarizer should be active or inactive; the controller is configured to output the second control signal indicating that the second spatially varying polarizer should be active in response to determining to perform the second optical correction on the light passing through the position corresponding to the second region within the correction portion.

3. The optical system according to claim 1 or 2.

4. the controller is configured to output the first control signal indicating that the first spatially varying polarizer should be inactive in response to determining to perform the second optical correction on the light passing through the position corresponding to the second region within the correction portion.

4. The optical system of claim 3.

5. the first and second spatially varying polarizers are in a stacked configuration such that the light passing through the correction portion is incident on the second spatially varying polarizer after passing through the first spatially varying polarizer; 5. An optical system according to any one of claims 1 to 4.

6. providing the first optical correction includes performing diffraction, light collimation, focusing, image sharpening, angular resolution modification, focal length modification, or aberration correction in response to a diffraction pattern; 6. An optical system according to any one of claims 1 to 5.

7. any one of the plurality of spatially varying polarizers includes a multi-twist retarder (MTR); 7. An optical system according to any one of claims 1 to 6.

8. a support structure; The display and a gaze tracker operable to track a user's gaze and output data representative of said gaze; an optical system having a first optical subsystem and a second optical subsystem, each of the first optical subsystem and the second optical subsystem including a correction portion including a plurality of spatially varying polarizers, a first spatially varying polarizer of the plurality of spatially varying polarizers including a first control input configured to receive a first control signal of a plurality of control signals indicating whether the first spatially varying polarizer should be active or inactive, the first spatially varying polarizer being operable, when active, to provide a first optical correction to light passing through a position within the correction portion corresponding to a first region of a plurality of regions of a virtual image; For each of the first optical subsystem and the second optical subsystem: receiving the data representing the gaze of the user; determining, based on the gaze, whether the first optical correction should be performed on the light passing through the position corresponding to the first region within the correction portion; outputting the first control signal indicating that the first spatially varying polarizer should be active in response to determining to perform the first optical correction on the light passing through the correction portion at the location corresponding to the first region; and a controller configured to: A head-mounted display system, wherein, for each of the first optical subsystem and the second optical subsystem, the controller is configured to determine that the gaze has changed based on the data representing the gaze and to decide to perform a second optical correction using a second spatially varying polarizer among the plurality of spatially varying polarizers on light passing through a position within the correction portion corresponding to a second region among the plurality of regions of the virtual image.

9. for each of the first optical subsystem and the second optical subsystem, the first region of the plurality of regions of the virtual image is within the field of view of the gaze of the user; The head-mounted display system according to claim 8 .

10. for each of the first optical subsystem and the second optical subsystem, the second spatially varying polarizer of the plurality of spatially varying polarizers has a second control input configured to receive a second control signal of the plurality of control signals indicating whether the second spatially varying polarizer should be active or inactive; for each of the first optical subsystem and the second optical subsystem, the controller is configured to output the second control signal indicating that the second spatially varying polarizer should be active in response to determining to perform the second optical correction on the light passing through the position corresponding to the second region within the correction portion. The head-mounted display system according to claim 8 or 9.

11. for each of the first optical subsystem and the second optical subsystem, the controller is configured to output the first control signal indicating that the first spatially varying polarizer should be inactive in response to determining to perform the second optical correction on the light passing through the position corresponding to the second region within the correction portion. The head-mounted display system according to claim 10.

12. for each of the first optical subsystem and the second optical subsystem, the first spatially varying polarizer and the second spatially varying polarizer are in a stacked configuration such that the light passing through the correction portion is incident on the second spatially varying polarizer after passing through the first spatially varying polarizer; The head mounted display system according to any one of claims 8 to 11.

13. and for each of the first optical subsystem and the second optical subsystem, providing the first optical correction includes performing diffraction, light collimation, focusing, image sharpening, angular resolution modification, focal length modification, or aberration correction in response to a diffraction pattern.

13. A head mounted display system according to any one of claims 8 to 12.

14. for each of the first optical subsystem and the second optical subsystem, any spatially varying polarizer of the plurality of spatially varying polarizers includes a multi-twist retarder (MTR); 14. A head mounted display system according to any one of claims 8 to 13.

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