Variable optical correction using spatially varying polarizers

Abstract

To enhance user experience or viewing, or to make corrections for one or more vision conditions of the user including myopia, hyperopia, and astigmatism.SOLUTION: A first spatially varying polarizer of one or more spatially varying polarizers of an optical system has a first control input configured to receive a first control signal indicating whether the first spatially varying polarizer is to be active or inactive. When active, the first spatially varying polarizer is operative to provide a first optical correction on light passing through the correction portion. The optical system includes a controller configured to: determine whether to implement the first optical correction on the light passing through the correction portion; and, in response to determining implementing the first optical correction on the light passing through the correction portion, output the first control signal indicating that the first spatially varying polarizer is to be active.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to an optical correction system that performs variable optical correction using a space-varying polarizer. [Background technology]

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

[0003] Existing HMDs do not take into account a user's visual impairment or deficiency. For example, a person with astigmatism, myopia, or hyperopia (also known as presbyopia) may wear eyeglasses to correct one or more of these conditions. However, previously implemented HMDs display visual content to a user without adapting virtual light to correct for these conditions. At least some HMDs do not have sufficient space in front of or around the user's eyes to allow the user to wear vision-correcting eyeglasses and the HMD. As a result, for a user with a visual impairment or deficiency who wears eyeglasses, visual content may appear out of focus or unclear, detracting from the overall user experience. Summary of the Invention

[0004] The head-mounted display may be summarized as comprising a virtual display unit and an optical system that modifies virtual image light. The optical system may modify the virtual image light to enhance the user experience or viewing or to correct one or more visual conditions of the user, including myopia, hyperopia, and astigmatism. The optical system may comprise a left optical subsystem and a right optical subsystem operable to modify the virtual image light received from the virtual display to correct left-eye and right-eye viewing, respectively.

[0005] The optical system includes one or more space-varying polarizers, each operable to be in an active (on) or inactive (off) state based on a controller input. The space-varying polarizers may be formed from multi-twist retarders (MTRs) and customized to provide precise levels of retardation in a single thin film. The space-varying polarizers may operate as corrective optical elements, causing light passing therethrough to be refracted (according to a refractive index) or diffracted (according to a diffraction pattern). The space-varying polarizers may be formed as polarization-directed lenses and may have electrically controllable focal lengths to focus and collimate the light passing therethrough.

[0006] Each space-varying polarizer may be formed to have, among other things, diffraction pattern, light-collimating, light-focusing, or aberration-correcting properties that act on light passing through it. Two or more space-varying polarizer subsets may be combined to have, among other things, particular diffraction, light-collimating, light-focusing, or aberration-correcting properties that act on light passing through them.

[0007] The controller may switch individual space-varying polarizers, a subset of the space-varying polarizers, or all available space-varying polarizers on or off to achieve and implement the corresponding optical correction. The controller may switch various space-varying polarizers between on and off states to switch between different available optical corrections.

[0008] The optical system may be summarized as comprising: a correction portion having one or more space-changing polarizers, a first space-changing polarizer of the one or more space-changing polarizers having a first control input configured to receive a first control signal indicating whether the first space-changing polarizer is to be active or inactive, and the first space-changing polarizer, when active, is operable to provide a first optical correction to light passing through the correction portion; and a controller configured to determine whether the first optical correction should be implemented to the light passing through the correction portion, and to output the first control signal indicating that the first space-changing polarizer is to be activated in response to determining to implement the first optical correction to the light passing through the correction portion.

[0009] The one or more space-changing polarizers may include a second space-changing polarizer in a stacked arrangement with the first space-changing polarizer, such that the light passing through the correction portion impinges on the second space-changing polarizer after passing through the first space-changing polarizer. The second space-changing polarizer may have a second control input configured to receive a second control signal indicating whether the second space-changing polarizer is active or inactive, and the second space-changing polarizer may be operable, when active, to provide a second optical correction to the light passing through the correction portion. The controller may be configured to determine to implement the second optical correction to the light passing through the correction portion, and in response to determining to implement the second optical correction to the light passing through the correction portion, output the first control signal indicating that the first space-changing polarizer is inactive and output the second control signal indicating that the second space-changing polarizer is active. The one or more space-changing polarizers may include a third space-changing polarizer in a stacked arrangement with the first space-changing polarizer and the second space-changing polarizer, such that the light passing through the correction portion impinges against the third space-changing polarizer after passing through the first space-changing polarizer and the second space-changing polarizer. The third space-changing polarizer may have a third control input configured to receive a third control signal indicating whether the third space-changing polarizer is active or inactive, and when active, the third space-changing polarizer may be operable to provide a third optical correction to the light passing through the correction portion.The controller may be configured to: determine to implement the third optical correction on the light passing through the correction portion; and, in response to determining to implement the third optical correction on the light passing through the correction portion, output the first control signal indicating that the first space-varying polarizer is deactivated, output the second control signal indicating that the second space-varying polarizer is deactivated, and output the third control signal indicating that the third space-varying polarizer is activated. Providing the first optical correction on the light passing through the correction portion may include performing diffraction according to a diffraction pattern, light collimation, light focusing, or aberration correction. The one or more space-varying polarizers may include a multi-twist retarder (MTR).

[0010] A head-mounted display system can be summarized as comprising: a support structure; a display; 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 one or more space-varying polarizers, a first space-varying polarizer of the one or more space-varying polarizers having a first control input configured to receive a first control signal indicating whether the first space-varying polarizer is to be activated or inactivated, the first space-varying polarizer, when active, being operable to provide a first optical correction to light passing through the correction portion; and a controller configured to: determine, for each of the first optical subsystem and the second optical subsystem, whether the first optical correction should be implemented on the light passing through the correction portion; and, in response to determining to implement the first optical correction on the light passing through the correction portion, output the first control signal indicating that the first space-varying polarizer is to be activated.

[0011] For each of the first optical subsystem and the second optical subsystem, the one or more space-changing polarizers may include a second space-changing polarizer in a stacked arrangement with the first space-changing polarizer, such that the light passing through the correction portion impinges against the second space-changing polarizer after passing through the first space-changing polarizer. For each of the first optical subsystem and the second optical subsystem, the second space-changing polarizer may have a second control input configured to receive a second control signal indicating whether the second space-changing polarizer is active or inactive, and when active, the second space-changing polarizer may be operable to provide a second optical correction to the light passing through the correction portion. For each of the first optical subsystem and the second optical subsystem, the controller may be configured to determine to implement the second optical correction on the light passing through the correction portion, and in response to determining to implement the second optical correction on the light passing through the correction portion, output the first control signal indicating that the first space-varying polarizer is to be inactive and output the second control signal indicating that the second space-varying polarizer is to be active.

[0012] For each of the first optical subsystem and the second optical subsystem, the one or more space-changing polarizers may include a third space-changing polarizer in a stacked arrangement with the first space-changing polarizer and the second space-changing polarizer, such that the light passing through the correction portion impinges against the third space-changing polarizer after passing through the first space-changing polarizer and the second space-changing polarizer. For each of the first optical subsystem and the second optical subsystem, the third space-changing polarizer may have a third control input configured to receive a third control signal indicating whether the third space-changing polarizer is active or inactive, and when active, the third space-changing polarizer may be operable to provide a third optical correction to the light passing through the correction portion. For each of the first optical subsystem and the second optical subsystem, the controller may be configured to determine to implement the third optical correction on the light passing through the correction portion, and in response to determining to implement the third optical correction on the light passing through the correction portion, output the first control signal indicating that the first space-varying polarizer is to be deactivated, output the second control signal indicating that the second space-varying polarizer is to be deactivated, and output the third control signal indicating that the third space-varying polarizer is to be activated. For each of the first optical subsystem and the second optical subsystem, providing the first optical correction on the light passing through the correction portion may include performing diffraction according to a diffraction pattern, light collimation, light focusing, or aberration correction. For each of the first optical subsystem and the second optical subsystem, the one or more space-varying polarizers may include a multi-twist retarder (MTR). [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is an overhead plan view of a head-mounted display having an optical system according to one or more implementations.

[0014] [Figure 2] FIG. 2 is a diagram of an optical subsystem of the optical system of the head-mounted display of FIG. 1.

[0015] [Figure 3] FIG. 2 is a perspective overhead view of the exterior of the head-mounted display of FIG. 1.

[0016] [Figure 4] FIG. 1 is a schematic block diagram of a head-mounted display.

[0017] [Figure 5] FIG. 5 shows a correction portion coupled to the controller described with reference to FIG. 4.

[0018] [Figure 6] 1 is an exemplary surface phase map for a space-varying polarizer according to one non-limiting illustrative implementation.

[0019] [Figure 7] 10 is another exemplary surface phase map for a space-varying polarizer according to one non-limiting illustrative implementation. DETAILED DESCRIPTION OF THE INVENTION

[0020] In the following description, certain specific details are set forth to provide a thorough understanding of various disclosed implementations. However, those skilled in the art will recognize that 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 associated with computer systems, server computers, and / or communication networks have not been shown or described in detail to avoid unnecessarily obscuring the description of these implementations.

[0021] Unless the context requires otherwise, throughout this specification and the claims that follow, the term "comprising" is synonymous with "including" and is inclusive or open-ended (i.e., does not exclude additional, unrecited elements or method actions). As used herein, references to the term "set" (e.g., "set of items") should be construed as a non-empty set that includes one or more members or instances, unless otherwise specified or contradicted by context.

[0022] References throughout this specification to "one implementation" or "an implementation" mean 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.

[0023] As used in this specification and 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 utilized to include "and / or" in its meaning unless the context clearly dictates otherwise.

[0024] The headings and abstract of the disclosure provided herein are for convenience only and do not interpret the scope or meaning of the implementations.

[0025] 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 via corresponding video presented at a display rate such as 30 frames (or images) per second or 90 frames per second, while other embodiments of similar systems may present an augmented reality display 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 display units 106 attached to or within a frame 108. The virtual display units 106 generate the virtual image light 102 for the user to perceive visual content. The HMD 100 may further include a left lens set 107l and a right lens set 107r provided on the emission side of the virtual display units 106. Left lens set 107l and right lens set 107r may focus, collimate, or otherwise modify virtual image light 102 after it is emitted from virtual display unit 106. Left lens set 107l and right lens set 107r may include, for example, Fresnel lenses that refract or collimate virtual image light 102.

[0026] HMD 100 also includes optical system 112 having optical properties that are selectively adjustable to correct one or more visual conditions of the user. For example, optical system 112 is selectively adjustable to correct one or more of myopia, hyperopia, and astigmatism, among others. Virtual image light 102 emitted from virtual display unit 106 travels along optical path 126 through optical system 112, which modifies virtual image light 102 according to the optical properties of optical system 112 and emits corrected virtual image light 114 to left eye 105l and right eye 105r of the user, respectively.

[0027] The frame 108 is a mounting structure that supports 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 for positioning in front of the user's eyes 105l and 105r for viewing generated visual content. The HMD 100 includes one or more support structures that selectively mount the HMD 100 on the user's head. For example, the HMD 100 of FIG. 1 includes left temples 122l and right temples 122r that rest on the user's left ear 124l and right ear 124r, respectively. In some embodiments, the HMD 100 may include another support structure, such as a strap connected to the body 116 that wraps around the back of the user's 104's head. A nose assembly (not shown) of the HMD 100 may support the body 116 on the user's 104's nose. The frame 108 may 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 purposes of explanation in a simplified manner similar to eyeglasses, it should be understood that in practice more elaborate structures (e.g., goggles, integrated headband, helmet, straps, etc.) may be used to support and position the HMD 100 on the head of the user 104.

[0028] The virtual display unit 106 generates virtual image light 102, which is transmitted through and selectively modified by optical system 112. The virtual display unit 106 includes a left display unit 106l that generates image light for presentation to left eye 105l and a right display unit 106r that generates image light for presentation to right eye 105r. The virtual 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 (LCos), or other light emitting technology to generate the virtual image light 102. The virtual display unit 106 in 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, the virtual display unit 106 may include a waveguide that directs (e.g., reflects, refracts) the virtual image light 102 toward the eyes 105l or 105r of the user 104 so that the light-emitting elements of the virtual display unit 106 are not directly in front of the eyes 105l and 105r of the user 104 to perceive visual content. In some embodiments, the front portion 118 of the body 116 may be at least partially transparent so that the user 104 may perceive external content to provide an augmented reality experience.

[0029] The HMD 100 includes an eye gaze tracker 127 configured to track the gaze (or direction) of the user 104 or the user's eyes 105l, 105r. While the eye gaze tracker 127 is shown as an internal element of the HMD 100, the eye gaze tracker 127 may be an external sensor in alternative embodiments. Furthermore, the eye gaze tracker 127 may perform gaze or pupil tracking separately for each eye 105l and 105r, or may track the location or orientation of the user's 104's head (e.g., as part of head tracking). Furthermore, the eye gaze tracker 127 may track various other types of movement and position of the user's body.

[0030] The gaze tracker 127 may output data representing the gaze of the user 104. The data may indicate a location (or area) on the viewing portion 120 to which the user 104 is directing his or her gaze. The location (or area) may be the center of the viewing portion 120, a quadrant of the viewing portion 120, or any other area of ​​the viewing portion 120.

[0031] While the described techniques may be used in some embodiments with a display system similar to that shown in FIG. 1 , in other embodiments, other types of display systems may be used, including those with a single optical lens and display device or those with multiple such optical lenses and display devices. Non-exclusive examples of other such devices include cameras, telescopes, microscopes, binoculars, spotting scopes, survey scopes, etc. Additionally, the described techniques may be used with a wide variety of display panels or other display devices that emit light to form images that one or more users view through one or more optical lenses. In other embodiments, a user may view one or more images through one or more optical lenses that are generated in a manner other than through a display panel, such as on a surface that partially or wholly reflects light from another light source.

[0032] The virtual image light 102 may include multiple light rays traveling from each of the virtual display units 106 along optical paths 126 through the optical system 112 toward the viewing portion 120. The optical system 112 corrects 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 that correct the virtual image light 102. The multiple optical subsystems 130 include a left optical subsystem 1301 that corrects the virtual image light 102 for the left eye 1051 and a right optical subsystem 130r that corrects the virtual image light 102 for the right eye 105r, although one optical subsystem 130 may be used to jointly correct the virtual image light 102 for both eyes 1051, 105r. Each of the left optical subsystem 130l and the right optical subsystem 130r may be independently adjustable to enhance the viewing experience of the user 104 or to correct visual deficiencies or impairments in the left eye 105l and the right eye 105r, respectively.

[0033] FIG. 2 shows a diagram 200 of optical subsystem 130 (e.g., optical subsystem 130l or 130r) of FIG. 1 according to one or more embodiments. Optical subsystem 130 includes a light-receiving portion 202 that receives initial virtual image light 204 corresponding to virtual image light 102 for one eye and an emission portion 206 that emits corrected virtual image light 208. Initial virtual image light 204 may include multiple light rays 205, each having a specific set of attributes (e.g., color, direction, brightness) that cause user 104 to perceive visual content. Optical subsystem 130 further includes a correction portion 210 that includes one or more space-varying polarizers 211, as described herein. Correction portion 210 corrects initial virtual image light 204 and emits corrected virtual image light 208.

[0034] Although three space-varying polarizers 211 (first space-varying polarizer 211a, second space-varying polarizer 211b, and third space-varying polarizer 211c) are shown in FIG. 2, the optical subsystem 130 may include any number of space-varying polarizers 211.

[0035] Each space-variant 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 to turn the space-variant polarizer 211 a, 211 b, 211 c on or off. The control signal may have a first state indicating to turn the space-variant polarizer 211 on and a second state indicating to turn the space-variant polarizer 211 off. The inputs 212 may be coupled to, and the control signals may be received from, a controller (not shown in FIG. 2 ) described herein.

[0036] The space-varying polarizer 211 may be formed from a multi-twist retarder (MTR), which is a waveplate-like retardation film that provides precise and customized levels of broadband, narrowband, or multiband retardation in a single thin film. More specifically, an MTR comprises two or more twisted liquid crystal (LC) layers on a single substrate and with a single alignment layer. Subsequent LC layers are directly aligned by the previous layer, thereby enabling simple fabrication and achieving automatic layer alignment, resulting in a monolithic film with a continuously varying optical axis.

[0037] The space-varying polarizer 211 may include a wave retarder formed from a birefringent material. Birefringence is a property of a material that has a refractive index that depends on the polarization and direction of propagation of light. The wave retarder alters the polarization state or phase of light traveling through it. The wave retarder may have a slow axis (or extraordinary axis) and a fast axis (or ordinary axis). When polarized light travels through the wave retarder, light along the fast axis travels more quickly than light along the slow axis.

[0038] The space-change polarizers 211 may be configured to operate as corrective optical elements. The birefringent material of the space-change polarizers 211 may be configured to cause light passing therethrough to be refracted (e.g., according to the refractive index). Each space-change polarizer 211 may have a diffraction pattern. The space-change polarizers 211 may be formed as polarizing direct lenses and may have electrically controllable focal lengths. Furthermore, the space-change polarizers 211 may perform collimation on the light passing therethrough.

[0039] One or more space-variant polarizers 211 of the correction portion 210 may operate individually, jointly, or in subsets as electrically controlled corrective optical elements. Each space-variant polarizer 211 may be formed to have, among other things, diffraction pattern properties, light collimation properties, light focusing properties, or aberration correction properties that act on light passing through it. Furthermore, a subset of two or more of the available space-variant polarizers 211 may combine to have, among other things, particular diffraction properties, light collimation properties, light focusing properties, or aberration correction properties that act on light passing through it. When that subset is activated (or switched on) and the other available space-variant polarizers 211 are deactivated (or switched off), that subset may operate on light passing therethrough according to the particular properties of that subset.

[0040] Each space-change polarizer 211a, 211b, 211c may be configured as an optical element to perform a specific optical correction. Additionally or alternatively, two or more space-change polarizers 211a may be configured as a combined optical element to perform a specific optical correction. The space-change polarizers 211a, 211b, 211c may be layered or stacked, such that multiple light rays 205 pass from the first space-change polarizer 211a to the second space-change polarizer 211b and then to the third space-change polarizer 211c. The first space-change polarizer 211a and the second space-change polarizer 211b are each configured to jointly perform a desired optical correction. The first space-change polarizer 211a may be configured to perform a first optical correction on light 205 impinging on the first space-change polarizer 211a. The second space-varying polarizer 211b may be configured to perform a second optical correction on light impinging on it (after being corrected by the first optical correction), the combination of the first optical correction and the second optical correction collectively achieving the desired optical correction.

[0041] Continuing with this example, the third space-variant polarizer 211c may be turned off so as not to obstruct or interfere with the desired optical correction performed by the first space-variant polarizer 211a and the second space-variant polarizer 211b. When turned off, the third space-variant polarizer 211c may not perform its own optical correction. Alternatively, when turned off, the third space-variant polarizer 211c may perform a third optical correction. In this case, the first optical correction and the second optical correction may be adjusted to compensate for (and reverse the effect of) the third optical correction to achieve the desired optical correction.

[0042] 3 illustrates an exterior 300 of the HMD 100 in accordance with 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 and securely attach the HMD 100 to the head of a user 104 who will view 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 optical properties of the optical system 112 to correct the visual content. The visual content can be corrected to improve the user's 104 experience and / or the user's 104 visual condition (e.g., myopia, hyperopia, astigmatism).

[0043] The input device may be an electrical device electrically coupled to the controller and configured to command the controller to configure the optical correction performed by the correction portion 210 and its one or more space-varying polarizers 211. As an example, the input device may cause an electrical signal to be sent to the controller in response to an interaction by the user 104, which in turn sends one or more control signals to each space-varying polarizer 211a, 211b, 211c 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 navigating a menu, or a dial or knob electrically coupled to the controller. The exterior 300 may include a display 306 that displays information about the HMD 100, such as the current optical settings of the optical system 112. In some embodiments, the display 306 may be a touchscreen input device that the user 104 may interact with to control the optical system 112.

[0044] In some embodiments, a user may adjust the optical settings of the optical system 112 in relation to visual content presented by the virtual display unit 106. For example, a user wearing the HMD 100 may interact with the control panel 304 or other input device (e.g., a handheld controller, a mouse, a keyboard) to adjust the optical settings according to menus or other visual content displayed by the virtual display unit 106. As one example, the user may navigate menus via the control panel 304 or other input device and provide user input, which in response changes the optical settings of the optical system 112. As another example, the HMD 100 may adjust the optical settings of the optical system 112 in real time in response to user input related to the visual content perceived by the user 104. The user may initiate a visual test on the HMD 100 that causes the virtual display unit 106 to display visual content, such as a test pattern, and prompts the user to provide input related to the clarity of the visual content. As a result of receiving the input, the HMD 100 may automatically adjust the optical settings of the optical system 112 to improve the clarity of the visual content and improve the experience of the user 104.

[0045] 4 is a block diagram 400 illustrating the interconnection of various portions of an HMD 100 according to one or more embodiments. The HMD 100 comprises a controller 402 comprising one or more processors 404 and a memory 406, the memory 406 storing 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. By way of 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 comprises a communication interface 408 electrically coupled to the controller 402 for sending and receiving communications with external devices. Communications interface 408 may include one or more wireless transceivers, such as a Wi-Fi® transceiver, a cellular transceiver, a Bluetooth® transceiver, etc., for wirelessly sending and receiving communications to and from external devices, such as a network router or computing device (e.g., laptop, desktop, tablet, mobile device). Communications interface 408 may include a wired communications port, such as a Universal Serial Bus port, a network interface port, etc., for wired communications with external devices.

[0046] The HMD 100 may include a set of input devices 410 electrically coupled to the controller 402 to provide user input to the HMD 100. One or more of the set of input devices 410 may be provided on the exterior 300 of the HMD 100, for example as part of the control panel 304. The controller 402 may also be electrically coupled to and configured to control the virtual display unit 106 and / or the display 306, if included. In some embodiments, the controller 402 may include one or more graphics processing units that generate the virtual image light 102 via the virtual display unit 106.

[0047] 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. In particular, 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.

[0048] Each correction portion 412, 416 may be configured as described herein with reference to FIG. 2 . The controller 402 is electrically coupled to the correction portions 412, 416 to control their respective space-varying polarizers 211. Specifically, the controller 402 sends signals (e.g., control signals) to the correction portions 412, 416 that cause the respective correction portions 412, 416 to perform optical correction by switching their respective space-varying polarizers 211 on and off. As described above, the correction portions 412, 416 may be controlled to modify their optical properties. The controller 402 may send a signal in response to receiving an input. For example, the controller 402 may cause the optical properties to be adjusted in response to receiving an input from the input device 410. As another example, the controller 402 may adjust the optical properties in response to receiving an input via the communication interface 408.

[0049] The inputs received by the controller 402 may have a particular format. The inputs may indicate a prescription for the right eye and / or a prescription for the left eye. For each eye, the inputs may indicate a power or spherical power (sometimes denoted as SPH or S), a cylinder power (sometimes denoted as CYL or C), and / or an axis (typically 0-180). The inputs may include inputs for the left optical subsystem 130l and the right optical subsystem 130r.

[0050] Adjustments to the optical settings of the optical system 112 may be adjusted in real time through feedback provided by the user 104. The controller 402 may initiate a test to determine adjustments to be made to the optical settings of the optical system 112. The test may include causing the virtual 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 the appearance of the visual content (e.g., text, images) appears unclear. The controller 402 may adjust the optical settings of the optical system 112 and ask the user 104 whether the adjustments improved the clarity of the appearance of the visual content. This process is iterative and may be repeated until the user 104 is satisfied with the clarity of the visual content. The test may be performed in response to receiving user input from the user 104 via the input device 410 or the control panel 304.

[0051] Input via communication interface 408 may be provided by a device (e.g., laptop, desktop, mobile device, controller) as a result of user interaction. The 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 characteristics for modifying virtual image light 102 to correct a visual condition of user 104. As described above, a user may enter input into input device 410 or the computing device as a prescription provided by a medical professional, which may have a predetermined format.

[0052] The controller 402 may determine signals to send 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 may access a data structure stored in the memory 406 that indicates, for example, the control signals to be sent to the corresponding correction portions 412, 416. The data structure may be an array, a look-up table, or other reference structure that associates input data with corresponding outputs (i.e., control signals) to be sent. In some implementations, the controller 402 may store information in the memory 406 that indicates the current state of the optical system 112, from which the controller 402 may determine adjustments to satisfy the received inputs.

[0053] In some embodiments, the space-varying polarizers 211 may be configured with advanced knowledge of the prescriptions or medical conditions of a user 104 or a set of potential users of the HMD 100 and may be tailored to the user 104 or set of potential users. In this case, the HMD 100 may be customized for the user 104 or set of potential users, which may be the user's friends or members of the user's household. For example, each space-varying polarizer 211 may be configured to optically correct for a particular user of the potential set of users. During use, the controller 402 may switch to a particular space-varying polarizer 211 depending on the identity of the user of the HMD 100.

[0054] The space-varying polarizer 211 may 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 may adjust the optical correction within this range to fine-tune the optical correction to provide optical correction that better suits the user's changed prescription. The variability of the optical correction provided by the correction portions 412, 416 described herein allows the optical correction to be adapted to new, anticipated, or predictable optical correction needs.

[0055] In some embodiments, the HMD 100 may be configured to detect the visual state 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 for use in conjunction with the sensors 424 to obtain information. The lighting elements 426 may emit light at an angle and with particular characteristics (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 regarding the eyes of the user 104, the controller 402 may adjust the optical properties of the optical system 112 accordingly.

[0056] 5 shows the correction section 210 coupled to the controller 402 described with reference to FIG. 4. The controller 402 has multiple outputs 214a, 214b, and 214c coupled to multiple inputs 212a, 212b, and 212c of a respective multiple space-varying polarizers 211a, 211b, and 211c. In the illustrated example, three layers of space-varying polarizers are shown for illustrative purposes, but fewer layers (e.g., one, two) or more layers (e.g., five, ten, twenty, etc.) may be used as needed in an application. The controller 402 sends control signals via each output 214 operable to activate or deactivate a space-varying polarizer 211.

[0057] When inactive, the space-changing polarizer 211 may be optically clear or may only perform the inherent optical correction associated with the material composition of the space-changing polarizer 211. Various types of materials have optical properties and are operable to change light. As described herein, the space-changing polarizer 211 may be formed from two or more twisted liquid crystal layers. The liquid crystal layers of the space-changing polarizer 211 may be turned off and still perform the inherent optical correction. When turned on, the space-changing polarizer 211 performs the optical correction it is designed to perform.

[0058] The first space-change polarizer 211a, the second space-change polarizer 211b, and the third space-change polarizer 211c are configured to perform a first optical correction, a second optical correction, and a third optical correction. In operation, the controller 402 sends control signals to the space-change polarizers 211a, 211b, and 211c to operate the space-change 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 space-change polarizer 211a to activate the first space-change polarizer 211a and sends respective control signals to the second space-change polarizer 211b and the third space-change polarizer 211c to deactivate the second space-change polarizer 211b and the third space-change polarizer 211c, respectively. The first optical correction may be a combination of a desired optical correction and optical compensation. The optical compensation may compensate for the inherent optical correction performed by the deactivated second and third space-variant polarizers 211 b, 211 c. Light exiting the first space-variant polarizer 211 a and traversing the deactivated second and third space-variant polarizers 211 b, 211 c is thus pre-corrected for the inherent optical correction performed by the deactivated second and third space-variant polarizers 211 b, 211 c.

[0059] In another example, the controller 402 may send a control signal to the first space-variant polarizer 211a to deactivate the first space-variant polarizer 211a, and may send control signals to the second space-variant polarizer 211b and the third space-variant polarizer 211c to activate the second space-variant polarizer 211b and the third space-variant polarizer 211c, respectively. The first optical correction provided by the second space-variant polarizer 211b and the third space-variant polarizer 211c is a combination of the second optical correction and the third optical correction. The controller 402 may selectively switch the space-variant polarizer 211 between an active state and an inactive state to cause the correction portion 210 to provide the optical correction.

[0060] The space-varying polarizers of the present disclosure may provide space-varying polarization defined by a surface phase map or by a combination of two or more surface phase maps multiplexed together. More generally, any linear or nonlinear function may be used to define the surface of one or more of the space-varying polarizers of the present disclosure to provide a desired function. FIGS. 6 and 7 show two non-limiting examples of surface phase maps for space-varying polarizers. In the example surface map 600 of FIG. 6, the phase varies concentrically from −0.433 wavelengths to +0.433 wavelengths from the center to the outer edge of the optical element. In the example surface map 700 of FIG. 7, the phase varies linearly from −1.25E+004 at the bottom of the optical element (as shown) to +1.25E+004 at the top of the optical element (as shown), each in units of a period of 2π radians. In applications, two or more space-varying polarizers may be stacked together. For example, concentric surface phase map 600 may be multiplexed with linear phase map 700, etc. Note that while the phase distribution of surface maps 600 and 700 is shown as discrete steps for simplicity, in practice the phase may be continuously variable across the surface of the optical element. Furthermore, the particular phase values ​​in surface phase maps 600 and 700 are provided as examples and should not be considered limiting.

[0061] In at least some implementations, the surface phase map of the space-varying polarizer may be designed to cancel or compensate for undesired polarization caused by at least one other component of the display system, such as a display source, a lens, etc. In such implementations, a phase profile or map of the optical system (e.g., a lens, or a lens and a display source) may first be determined. The determined phase map may then be inverted and applied to the space-varying polarizer, such that the space-varying polarizer cancels or compensates for undesired effects caused by the other components of the optical system.

[0062] 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 general, in the following claims, the terms used 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 range of equivalents to which such claims are entitled. Accordingly, the claims are not limited by this disclosure.

Claims

[Claim 1] a correction portion having one or more space-varying polarizers, a first space-varying polarizer of the one or more space-varying polarizers having a first control input configured to receive a first control signal indicating whether the first space-varying polarizer is active or inactive, the first space-varying polarizer, when active, being operable to provide a first optical correction to light passing through the correction portion; a controller, determining whether to implement the first optical correction on the light passing through the correction portion; outputting the first control signal indicating that the first space-varying polarizer is to be activated in response to determining to implement the first optical correction for the light passing through the correction portion; a controller configured to: An optical system comprising:

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