Folding optical device for head mounted display

Abstract

A lens system for a head mounted display includes a first lens, a second lens, a first wave plate, a partial reflector, and a second wave plate. The partial reflector is located between the first lens and the second lens. The first wave plate is located between the first lens and the partial reflector. The second wave plate is located between the second lens and the partial reflector. The reflective polarizer is on curved surfaces of the first lens and the second lens.

Description

Cross-references to related applications

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 490,170, filed March 14, 2023, the entire contents of which are incorporated herein by reference for all purposes. Background Technology

[0002] The following disclosure generally relates to head-mounted displays. A head-mounted display (HMD) is an electronic device or system worn on a user's head, and when worn, it fixes at least one electronic display within the visual field of view of at least one of the user's eyes, regardless of the position or orientation of the user's head. HMDs used to implement virtual reality (VR) typically completely cover the wearer's eyes and replace the actual field of view (or actual reality) in front of the user with a "virtual" reality. HMDs used for augmented reality (AR) can provide a semi-transparent or transparent overlay that provides one or more screens in front of the wearer's eyes, thereby enhancing the actual field of view with additional information. In some AR devices, the "display" component of the HMD can be transparent or located at the periphery of the user's field of view, so that the "display" component of the HMD does not completely obstruct the user's ability to see their external environment. In some AR devices, the display overlays digital content onto a video feed from a camera that acquires images of a real-world scene. Mixed reality (MR) is an interaction between the digital world and the physical world. Extended reality (ER) can be used to refer to VR, AR, and / or MR. Summary of the Invention

[0003] A lens system for a head-mounted display is used to focus light from the display onto a user's eye box. In some configurations, a lens system for a head-mounted display includes a first lens, a second lens, a first waveplate, a partial reflector, and a second waveplate. The partial reflector is located between the first and second lenses. The first waveplate is located between the first lens and the partial reflector. The second waveplate is located between the second lens and the partial reflector. A reflective polarizer may be located on a curved surface of the first and second lenses. The second lens may have the same shape as the first lens.

[0004] In some configurations, an apparatus for folding optics in a head-mounted display includes a display and a lens system. The lens system is arranged to focus light from the display onto a user's eye. The lens system includes: a first lens having a first surface and a second surface, the second surface opposite to the first surface, the first surface being curved, the first lens having a first thickness profile, and / or the first thickness profile being measured between the first and second surfaces of the first lens; a second lens having a third surface and a fourth surface, the fourth surface opposite to the third surface, the fourth surface being curved, the second lens having a second thickness profile, the second thickness profile being measured between the third and fourth surfaces, the second thickness profile being identical to the first thickness profile, the second lens being symmetrically arranged relative to the first lens such that the first... The three surfaces are closer to the second surface than the first surface, and / or the second surface is closer to the third surface than the fourth surface; a partial reflector located between the first lens and the second lens; a first waveplate located between the partial reflector and the first lens; a second waveplate located between the partial reflector and the second lens; a first reflective polarizer arranged such that the first lens is located between the first waveplate and the first reflective polarizer; and / or a second reflective polarizer arranged such that the second lens is located between the second waveplate and the second reflective polarizer.

[0005] In some embodiments, a first thickness profile corresponds to a plano-convex lens; a first reflective polarizer is on a first surface; a second reflective polarizer is on a fourth surface; a first waveplate and a second waveplate are quarter-wave plates; the fast axes of the first waveplate and the second waveplate are oriented in similar directions. The second surface of the first lens and the third surface of the second lens are flat; the first waveplate is attached to the first lens; the second waveplate is attached to the second lens; the first waveplate is attached to a partial reflector; the second waveplate is attached to a partial reflector; the first waveplate, the second waveplate, and the partial reflector are flat; and / or the device is part of a virtual reality headset.

[0006] In some configurations, a method for using foldable optics in a head-mounted display includes: transmitting light from the display through a first reflective polarizer and a first lens, wherein the first lens has a first surface and a second surface, the second surface being opposite to the first surface, the first surface being curved, the first lens having a first thickness profile, and / or the first thickness profile being measured between the first surface and the second surface of the first lens; transmitting light from the first lens through a first waveplate and to a partial reflector, wherein the first waveplate is located between the partial reflector and the first lens, and / or the first lens is located between the first waveplate and the first reflective polarizer. Light from a partial reflector is transmitted through a second waveplate and to a second lens, wherein the partial reflector is located between a first lens and a second lens, the second waveplate is located between the partial reflector and the second lens, the second lens has a third surface and a fourth surface, the fourth surface being opposite to the third surface and being curved, the second lens having a second thickness profile, the second thickness profile being measured between the third and fourth surfaces and being identical to the first thickness profile, the second lens being symmetrically arranged relative to the first lens such that the third surface is closer to the second surface than the surface closest to the first surface, and / or the second surface is closer to the third surface than the surface closest to the fourth surface; light is transmitted through the second lens and to a second reflective polarizer, wherein the second lens is located between the second waveplate and the second reflective polarizer.

[0007] In some embodiments, the method further includes reflecting the light from the partial reflector to a first reflective polarizer and having the light reflected by the first reflective polarizer before transmitting the light from the partial reflector through a second waveplate; having the light reflected by a second reflective polarizer to the partial reflector; and / or transmitting the light from the partial reflector through a second lens and through a second reflective polarizer.

[0008] Further applicability of this disclosure will become apparent from the specific embodiments provided below. It should be understood that while the specific embodiments and examples indicate various examples, they are intended for illustrative purposes only and are not intended to limit the scope of this disclosure. Attached Figure Description

[0009] This disclosure is described in conjunction with the accompanying drawings.

[0010] Figure 1 This is a schematic diagram of an embodiment of a networking environment for a head-mounted display (HDM).

[0011] Figure 2 This is a diagram illustrating an embodiment of an environment using an HMD.

[0012] Figure 3 This is a front view of an embodiment of an HMD with a binocular display subsystem.

[0013] Figure 4 A top plan view of an embodiment of an HMD with a binocular display subsystem and various sensors is shown.

[0014] Figure 5 This is an exploded view of an embodiment of a lens system using folding optics.

[0015] Figure 6 An embodiment of the first path of light in a lens system is depicted.

[0016] Figure 7 An embodiment of a second path of light in a lens system is depicted.

[0017] Figure 8 This is a ray tracing diagram of an embodiment of the first path of light in a lens system.

[0018] Figure 9 This is a ray tracing diagram of an embodiment of the second path of light in a lens system.

[0019] Figure 10 This is a ray tracing diagram of an embodiment of the first and second paths of light in a lens system.

[0020] Figure 11 A flowchart depicts an embodiment of a process for using foldable optics in a head-mounted display.

[0021] Figure 12 A flowchart depicting another embodiment of the process for using foldable optics in a head-mounted display is provided.

[0022] In the accompanying drawings, similar parts and / or features may have the same reference numerals. Furthermore, parts of the same type may be distinguished by a dash following the reference numeral and a second reference numeral used to differentiate between similar parts. If only the first reference numeral is used in the description, the description may apply to any of the similar parts having the same first reference numeral regardless of the second reference numeral. Detailed Implementation

[0023] The following description provides only preferred exemplary embodiments (one or more) and is not intended to limit the scope, applicability, or configuration of this disclosure. Rather, the subsequent description of preferred exemplary embodiments (one or more) will provide those skilled in the art with a description of implementations of the preferred exemplary embodiments. It should be understood that various changes may be made to the function and arrangement of the elements without departing from the spirit and scope set forth in the appended claims.

[0024] Foldable optics can be used to fold optical paths to reduce the shape factor of a lens system. An example of foldable optics in head-mounted displays is the pancake lens. Some pancake lenses have an efficiency limit of 25% because light is incident twice on partial mirrors. In some embodiments, a reflective polarizer is used in the lens system to recapture some of the light reflected by the partial mirrors. In some embodiments, the theoretical loss of the lens system (e.g., using foldable optics and a reflective polarizer) is 50%.

[0025] For illustrative purposes, some embodiments are described below in which specific types of information are acquired and used in a specific manner for a specific type of structure and by using a specific type of device. However, it should be understood that the techniques described thus can be used in other ways in other embodiments, and this disclosure is therefore not limited to the exemplary details provided. As a non-exclusive example, some embodiments include the use of images as video frames. While for convenience, "example" may refer to "video frame," it should be understood that the techniques described in the examples can be employed for one or more images of various types. "Video frame" includes non-exclusive examples of consecutive video frames (e.g., 30, 60, 90, 180, or some other number of frames per second), other video content, photographs, computer-generated graphic content, other items of visual media, or some combination thereof. Furthermore, various details are provided in the drawings and text for illustrative purposes and are not intended to limit the scope of this disclosure.

[0026] Figure 1 This is a schematic diagram of an embodiment of a networked environment 100. The networked environment 100 includes a local media rendering (LMR) system 110 (e.g., a gaming system), which includes a local computing system 120 and a display device 180 (e.g., an HMD device with two display panels). Figure 1 In this context, the local computing system 120 is connected via a transmission link 115 (which can be wired or cabled, such as via...). Figure 2 One or more cables (cable 220) shown, or alternatively wireless, are communicatively connected to display device 180. In some embodiments, local computing system 120 may provide encoded image data for display to flat panel display devices (e.g., TVs, consoles, or monitors) via wired or wireless links, either as a supplement to or in place of HMD device 180, and each display device includes one or more addressable pixel arrays. In some embodiments, local computing system 120 may include general-purpose computing systems; game consoles; video streaming devices; mobile computing devices (e.g., cellular phones, PDAs, or other mobile devices); VR or AR processing devices; or other computing systems.

[0027] A pixel is the smallest addressable image element of a display that can be activated to provide color values. In some cases, a pixel comprises independent, corresponding sub-elements (in some cases as separate "subpixels") for individually producing red, green, and blue light for human perception, where separate color channels are used to encode the pixel values ​​of the subpixels of different colors. A pixel value is a data value corresponding to a corresponding stimulus level in one or more of the corresponding RGB elements of a single pixel.

[0028] exist Figure 1 In this local computing system 120, components include one or more hardware processors (e.g., a centralized processing unit or "CPU") 125, memory 130, various I / O ("input / output") hardware components 127 (e.g., a keyboard, mouse, one or more game controllers, speakers, microphones, IR transmitters and / or receivers, etc.), a video subsystem 140 including one or more dedicated hardware processors (e.g., a graphics processing unit or "GPU") 144 and video memory (VRAM) 148, a computer-readable storage device 150, and a network connection 160. Embodiments of the eye-tracking subsystem 135 are executed in memory 130 to perform one or more processes, such as performing automated operations by using one or more CPUs 125 and / or one or more GPUs 144. Memory 130 may optionally further execute one or more other programs 133 (e.g., to generate video or other images to be displayed, such as a game program). As part of the automated operation, the eye-tracking subsystem 135 and / or program 133 executing in memory 130 can store or retrieve various types of data, including data in an example database data structure of storage device 150. In this example, the data used may include various types of image data 154 information in the database (“DB”), various types of application data 152 in the DB, various types of configuration data 157 in the DB, and may include additional information such as system data or other information.

[0029] LMR system 110 is communicatively connected to an exemplary network-accessible media content provider 190 via one or more computer networks 101 and network links 102. The exemplary network-accessible media content provider 190 may further provide content to the LMR system 110 for display, either as a supplement to or in place of the image generation program 133. The media content provider 190 may include one or more computing systems (not shown), each of which may have components similar to those of the local computing system 120, including one or more hardware processors, I / O components, local storage devices, and memory; however, for simplicity, some details are not illustrated for the network-accessible media content provider.

[0030] It should be understood that although display device 180 is described as being with Figure 1 The local computing system 120 is different and separate, but in some embodiments, some or all components of the local media rendering system 110 may be integrated or housed in a single device, such as a mobile gaming device, a portable VR entertainment system, an HMD device, etc. In some embodiments, the transmission link 115 may include, for example, one or more system buses and / or video bus architectures.

[0031] As an example involving operations performed locally by the local media rendering system 120, assuming the local computing system is a game computing system, application data 152 includes one or more game applications executed via CPU 125 using memory 130, and various video frame display data is generated and / or processed by image generation program 133 (such as in conjunction with GPU 144 of video subsystem 140). To provide a superior gaming experience, a large amount of video frame data (corresponding to high image resolution per video frame and a high "frame rate" of approximately 60-180 such video frames per second) is generated by the local computing system 120 and provided to the display device 180 via wired or wireless transmission link 115.

[0032] It should also be understood that computing system 120 and display device 180 are illustrative only and are not intended to limit the scope of this disclosure. Computing system 120 may alternatively include multiple interacting computing systems or devices and may include other devices connected via one or more networks such as the Internet, via the Web, or via a dedicated network (e.g., a mobile communication network, etc.) that are not shown. More generally, computing systems or other computing nodes may include any combination of hardware or software capable of interacting and performing functions of the types described, including, but not limited to: desktop or other computers, gaming systems, database servers, network storage devices and other network devices, PDAs, cellular phones, wireless phones, pagers, electronic notebooks, Internet devices, television-based systems (e.g., using set-top boxes and / or personal / digital video recorders), and various other consumer products including appropriate communication capabilities. Display device 180 may similarly include one or more devices having one or more display panels of various types and forms, and optionally include various other hardware and / or software components.

[0033] Additionally, in some embodiments, the functionality provided by the eye-tracking subsystem 135 may be distributed across one or more components, and in some embodiments, some functionality of the eye-tracking subsystem 135 may not be provided and / or other additional functionality may be available. It will also be understood that while various items are shown as being stored in memory or on a storage device during use, these items, or portions thereof, may be transferred between memory and other storage devices for memory management or data integrity purposes. Therefore, in some embodiments, the technology may be implemented by hardware, including one or more processors or other configured hardware circuitry or memory or storage devices, such as when configured by one or more software programs (e.g., by the eye-tracking subsystem 135 or components thereof) and / or data structures (e.g., by executing software instructions of one or more software programs and / or by storing such software instructions and / or data structures). Some or all of the components, systems, and / or data structures may be stored (e.g., as software instructions or structured data) on non-transient computer-readable storage media, such as hard disk or flash drives or other non-volatile storage devices, volatile or non-volatile memories (e.g., RAM), network storage devices, or portable media articles, for access by a suitable drive (e.g., DVD, CD, optical disc, etc.) or via a suitable connection. In some embodiments, the systems, components, and data structures may also be transmitted as generated data signals (e.g., as part of a carrier wave or other analog or digital propagation signal) over various computer-readable transmission media, including wireless and wired / cable-based media, and may take various forms (e.g., as part of a single or multiplexed analog signal, or as multiple discrete digital packets or frames). In some embodiments, such computer program products may also take other forms.

[0034] Figure 2 An embodiment of an environment 200 is illustrated for use with an example HMD device 202, which is coupled to a video rendering computing system 204 via a tethered connection 220 (or wirelessly in some embodiments) to provide a virtual reality display to a human user 206. The user wears the HMD device 202 and receives display information about a simulated environment, distinct from the actual physical environment, from the computing system 204 via the HMD device. The computing system acts as an image rendering system, supplying images of the simulated environment (such as images generated by game programs and / or other software programs running on the computing system) to the HMD device for display to the user. In this example, the user is further able to move within a tracked volume 201 of the actual physical environment 200 and may further have one or more I / O (“input / output”) devices to allow further interaction with the simulated environment, which in this example includes handheld controllers 208 and 210.

[0035] In the illustrated example, environment 200 may include one or more base stations 214 (two are shown, labeled base stations 214-a and 214-b) that can facilitate tracking of HMD device 202 or controllers 208 and 210. The location of the HMD device is tracked as the user moves the position of HMD device 202 or changes its orientation, such as to allow the corresponding portion of the simulated environment to be displayed to the user on the HMD device. Controllers 208 and 210 may further employ similar techniques to track the location of the controller (and optionally use this information to help determine or verify the location of the HMD device). After the tracked location of HMD device 202 is known, the corresponding information is transmitted via tether 220 or wirelessly to computing system 204, which uses the tracked location information to generate one or more next images of the simulated environment to display to the user.

[0036] There are many position tracking methods that can be used in various embodiments of this disclosure, including but not limited to acoustic tracking, inertial tracking, magnetic tracking, optical tracking, and combinations thereof.

[0037] In some implementations, the HMD device 202 includes one or more optical receivers or sensors that can be used to implement tracking functionality or other aspects of this disclosure. For example, base stations 214 may each scan optical signals across the tracked volume 201. Depending on the requirements of each particular implementation, each base station 214 may generate more than one optical signal. For example, while a single base station 214 may be sufficient for six-degree-of-freedom tracking, in some embodiments multiple base stations (e.g., base stations 214a, 214b) may be used to provide robust room-scale tracking for the HMD device and / or peripheral devices. In this example, optical receivers are incorporated into the HMD device 202 and / or other tracked objects (such as controllers 208 and 210). In some embodiments, the optical receivers may be paired with accelerometers and gyroscopes on each tracked device to support low-latency sensor fusion.

[0038] In some implementations, each base station 214 includes two rotors that scan a linear beam across the tracked volume 201 along orthogonal axes. At the start of each scan cycle, the base station 214 may emit an omnidirectional light pulse (referred to as a "synchronization signal") visible to sensors on the tracked object. Each sensor then calculates a unique angular position within the scanned volume by timing the duration between the synchronization signal and the beam signal. Sensor distance and orientation can be determined using multiple sensors fixed to a single rigid body.

[0039] One or more sensors positioned on the tracked object (e.g., HMD device 202, controllers 208 and 210) may include optoelectronic devices capable of detecting modulated light from the rotor. For visible or near-infrared (NIR) light, silicon photodiodes and suitable amplifier / detector circuitry may be used. Because the environment 200 may contain static and time-varying signals (optical noise) with wavelengths similar to the signal from base station 214, in some embodiments, the base station light may be modulated in such a way that it is easily distinguishable from any interfering signals, and / or the sensors may be filtered to remove radiation of wavelengths other than the wavelength of the base station signal.

[0040] Inside-out tracking is also a type of position tracking that can be used to track the position of HMD device 202 and / or other objects (e.g., controllers 208 and 210, tablet computers, smartphones). The difference between inside-out tracking and outside-in tracking lies in the position of the camera or other sensors used to determine the HMD's position. In inside-out tracking, the camera or sensor is located on the HMD or the object being tracked, while in outside-out tracking, the camera or sensor is placed in a fixed position within the environment.

[0041] Inside-out tracking HMDs utilize one or more cameras "looking out" to determine how their position changes relative to the environment. As the HMD moves, the sensors readjust their positions within the room, and the virtual environment responds accordingly in real time. This type of position tracking can be achieved with or without markers placed in the environment. Cameras placed on the HMD observe features of the surrounding environment. When markers are used, they are designed to be easily detected by the tracking system and placed in specific areas. Using "markerless" inside-out tracking, the HMD system uses unique characteristics initially present in the environment (e.g., natural features) to determine position and orientation. The HMD system's algorithms identify specific images or shapes and use them to calculate the device's position in space. Data from accelerometers and gyroscopes can also be used to improve the accuracy of position tracking.

[0042] Figure 3 Information 300 illustrates a front view of an example HMD device 344 when worn on the head of user 342. The HMD device 344 includes a front-facing structure 343 that supports a forward-facing or forward-looking camera 346 and multiple sensors 348a-348d (collectively referred to as 348) of one or more types. As an example, some or all of the sensors 348 (such as those used for detection and those used from one or more external devices (not shown, e.g., [missing information])) Figure 2A light sensor (emitting light information from a base station 214) can assist in determining the location and / or orientation of the device 344 in space. As shown, a forward-looking camera 346 and sensor 348 are guided forward toward an actual scene or environment (not shown) in which a user 342 operates the HMD device 344. The actual physical environment may include, for example, one or more objects (e.g., walls, ceilings, furniture, stairs, cars, trees, tracking markers, or any other type of object). The specific number of sensors 348 may be less or more than the number of sensors depicted. The HMD device 344 may further include one or more additional components not attached to the forward-looking structure (e.g., inside the HMD device), such as IMU (Inertial Measurement Unit) 347 electronics (e.g., using a combination of accelerometers and gyroscopes, and optionally magnetometers) that measure and report specific forces, angular rates, and / or magnetic fields around the HMD device 344. HMD devices may further include additional components (not shown), including one or more display panels and optical lens systems oriented toward the user's eyes (not shown), and optionally have one or more attached internal motors to change the alignment or other positioning of one or more of the optical lens systems and / or display panels within the HMD device, as described below. Figure 4 To be discussed in more detail.

[0043] The illustrated example of HMD device 344 is supported on the head of user 342 based at least in part on a housing attached to HMD device 344 and extending wholly or partially around the user's head via one or more straps 345. Although not shown here, HMD device 344 may further have one or more external motors, such as those attached to one or more of the straps 345, and automatic correction actions may include using such motors to adjust such straps to modify the alignment or other positioning of the HMD device on the user's head. It should be understood that HMD devices may include other support structures (e.g., nose clips, chin straps, etc.) not shown here, either as a supplement to or in place of the straps shown, and some embodiments may include motors attached to one or more of these other support structures to similarly adjust their shape and / or position to modify the alignment or other positioning of the HMD device on the user's head. Other display devices not fixed to the user's head may be similarly attached to or as part of one or more structures that affect the positioning of the display device and, in some embodiments, may include motors or other mechanical actuators that similarly modify their shape and / or position to modify the alignment or other positioning of the display device relative to one or more pupils of one or more users of the display device.

[0044] Figure 4A simplified top plan view 400 is shown of an embodiment of an HMD device 405 including a pair of near-eye display systems 402 and 404. For example, the HMD device 405 may be... Figures 1-3 The same or similar HMD devices or different HMD devices shown herein, and the HMD devices discussed herein may be further used in the examples discussed below. Figure 4 The near-eye display systems 402 and 404 respectively include display panels 406 and 408 (e.g., OLED microdisplays) and corresponding optical lens systems 410 and 412, each having one or more optical lenses. Display systems 402 and 404 can be mounted into or otherwise positioned within a housing (or frame) 414, which includes a forward portion 416 (e.g., with...). Figure 3 The front surface 343 is the same as or similar to the front surface 443, the left temple 418, the right temple 420, and the inner surface 421 that contacts or approaches the face of the wearer 424 when the user wears the HMD device. The two display systems 402 and 404 can be fixed to the housing 414 in an eyeglass arrangement that can be worn on the head 422 of the wearer 424, wherein the left temple 418 and the right temple 420 rest on the user's ears 426 and 428 respectively, and the nose assembly 492 can rest on the user's nose 430. Figure 4 In the example, the HMD device 405 may be partially or entirely supported on the user's head by the nose display and / or the temples of the left and right earpieces, although in some embodiments, straps (not shown) or other structures may be used to secure the HMD device to the user's head, such as Figure 2 and Figure 3 The embodiment shown. The shape and size of housing 414 can be designed to position each of the two optical lens systems 410 and 412 in front of one of the user's eyes 432 and 434, respectively, such that the target position of each pupil 494 is vertically and horizontally centered in front of the corresponding optical lens system and / or display panel. Although housing 414 is shown in a simplified manner similar to eyeglasses for illustrative purposes, it should be understood that in practice, more complex structures (e.g., goggles, integrated headbands, helmets, straps, etc.) can be used to support and position display systems 402 and 404 on the head 422 of user 424.

[0045] Figure 4 The HMD device 405 is arranged to present a virtual reality display to a user, such as via corresponding video presented at a display rate of such as 30, 60, or 90 frames per second (or images). In some embodiments, the HMD device may present an augmented reality display to the user. Figure 4Each of the displays 406 and 408 can generate light that is transmitted through and focused by corresponding optical lens systems 410 and 412 onto the eyes 432 and 434 of the user 424. The pupil 494 of each eye (through which light enters the eye) typically has a pupil size ranging from 2 mm in diameter under very bright conditions to up to 8 mm in dark conditions, while the larger iris containing the pupil can have a size of approximately 12 mm. The pupil (and the surrounding iris) can further move several millimeters horizontally and / or vertically within the visible portion of the eye under open eyelids, which also moves the pupil to different horizontal and vertical positions at different depths from the optical lenses or other physical elements of the display (resulting in a three-dimensional volume in which the pupil can move). The light entering the user's pupil is perceived by the user 424 as an image and / or video. In some embodiments, the distance between each of the optical lens systems 410 and 412 and the user's eyes 432 and 434 can be relatively short (e.g., less than 30 mm, less than 20 mm), which advantageously makes the HMD device lighter for the user because the weight of the optical lens system and display system is relatively close to the user's face, and also provides the user with a larger field of view. Some embodiments of the HMD device may include various additional internal and / or external sensors.

[0046] exist Figure 4 In this embodiment, HMD device 405 includes hardware sensors and additional components, such as one or more accelerometers and / or gyroscopes 490 (e.g., as part of one or more IMU units). Values ​​from the accelerometers and / or gyroscopes can be used to locally determine the orientation of the HMD device. Additionally, HMD device 405 may include one or more forward-facing cameras, such as one or more cameras 485 on the exterior of the front panel 416, and their information can be used as part of the operation of the HMD device, such as for providing AR or positioning functions. Furthermore, HMD device 405 may further include other components 475 (e.g., electronic circuitry for controlling image display on display panels 406 and 408, internal memory, one or more batteries, location tracking devices for interacting with external base stations, etc.). Some embodiments may exclude one or more of components 475, 485, and / or 490. Some embodiments of the HMD device may include various additional internal and / or external sensors, such as various other types of movement and position for tracking the user's body, eyes, controllers, etc.

[0047] HMD device 405 further includes hardware sensors and additional components for determining the user's pupil or gaze direction, which may be provided to one or more components associated with the HMD device for use. The hardware sensors include one or more eye-tracking components 472 of an eye-tracking subsystem, mounted on or near the display panels 406 and 408 and / or located on the inner surface 421 near the optical lens systems 410 and 412, for acquiring information about the actual position of the user's pupil 494, such as individually for each pupil in this example.

[0048] Each of the tracking components 472 may include one or more light sources (e.g., IR LEDs) and one or more photodetectors (e.g., photodiodes). Furthermore, although for clarity... Figure 4 Only a total of four eye-tracking components 472 are shown, but it should be understood that a different number of eye-tracking components may be provided in practice. In some embodiments, a total of eight eye-tracking components 472 are provided, with four eye-tracking components for each eye of the user 424. Furthermore, in some embodiments, each eye-tracking component includes a light source facing one of the user's eyes 432 and 434, a photodetector positioned to receive light reflected by the user's respective eye, and a polarizer positioned and configured to prevent light reflected via specular reflection from being applied to the photodetector.

[0049] Information from the eye-tracking component 472 can be used to determine and track the user's gaze direction during use of the HMD device 405. Furthermore, in some embodiments, the HMD device 405 may include one or more internal motors 438 (or other movement mechanisms) that can be used to move 439 of the optical lens systems 410 and 412 and / or display panels 406 and 408 within the housing of the HMD device 405 for alignment and / or other positioning (e.g., in vertical, horizontal left-right, and / or horizontal front-back directions), such as to personalize or otherwise adjust the target pupil position of one or both of the near-eye display systems 402 and 404 to correspond to the actual position of one or both of the pupils 494. Such motors 438 can be controlled, for example, by user manipulation of one or more controllers 437 on the housing 414 and / or via user manipulation of one or more associated individual I / O controllers (not shown). In some embodiments, the HMD device 405 can control the alignment and / or other positioning of the optical lens systems 410 and 412 and / or display panels 406 and 408 without such a motor 438, such as by using an adjustable positioning mechanism (e.g., screw, slider, ratchet, etc.) that is manually changed by the user via control 437. Although in Figure 4Motor 438 is shown for only one of the near-eye display systems, but each near-eye display system may have its own one or more motors, and in some embodiments, one or more motors may be used (e.g., independently) to control each of the multiple near-eye display systems.

[0050] In some embodiments, other types of display systems may be used, including those used with a single optical lens and display device, or with multiple such optical lenses and display devices. Non-exclusive examples of other such devices include cameras, telescopes, microscopes, binoculars, positioning mirrors, measuring mirrors, etc. Additionally, various display panels or other display devices that emit light to form images may be used, which are viewed by one or more users through one or more optical lenses. In some embodiments, a user may view one or more images through one or more optical lenses that are produced in a manner different from that via a display panel (such as on a surface that partially or completely reflects light from another light source).

[0051] Figure 5 This is an exploded view of an embodiment using a lens system for a foldable optics device for a head-mounted display. The lens system is arranged to focus light from a display 504 (e.g., a projector) onto a user's eye (e.g., a viewing window 508). The lens system includes a first lens 512-1, a second lens 512-2, a partial reflector 516, a first waveplate 520-1, a second waveplate 520-2, a first reflective polarizer 524-1, and a second reflective polarizer 524-2.

[0052] The first lens 512-1 has a first surface 528 and a second surface 532. The second surface 532 is opposite to the first surface 528. The first surface 528 is curved (e.g., to focus light from the display 504 onto the viewing window 508). The first lens 512-1 has a first thickness profile. The first thickness profile is measured between the first surface 528 and the second surface 532 of the first lens 512-1. For example, the thickness profile is the thickness d of the lens 512, measured in the z-dimensional (e.g., d-1 of the first lens 512-1 and d-2 of the second lens 512-2) at a given location (e.g., x, y) of the lens 512.

[0053] The second lens 512-2 has a third surface 536 and a fourth surface 540. The fourth surface 540 is opposite to the third surface 536. The fourth surface 540 is curved (e.g., to focus light from the display 504 onto the viewing window 508). The second lens 512-2 has a second thickness profile. The second thickness profile is measured between the third surface 536 and the fourth surface 540 (e.g., in the z-direction). The second thickness profile is the same as the first thickness profile (e.g., for each (x, y) of the lens 512, d-1 = d-2). For example, the first thickness profile (and the second thickness profile) is used for a plano-convex lens. The second lens 512-2 is arranged symmetrically with respect to the first lens 512-1, such that the third surface 536 is closer to the second surface 532 than to the first surface 528, and the second surface 532 is closer to the third surface 536 than to the fourth surface 540. Making the second lens 512-2 identical to the first lens 512-1 (e.g., with the same profile) allows the lens system to have fewer unique components and / or simplifies production.

[0054] A partial reflector 516 is located between a first lens 512-1 and a second lens 512-2. In some embodiments, the partial reflector 516 is a 50 / 50 mirror. A first waveplate 520-1 is located between the partial reflector 516 and the first lens 512-1. A second waveplate 520-2 is located between the partial reflector 516 and the second lens 512-2. A waveplate is an optical retarder. An optical retarder is an optical element that introduces a relative phase shift between the constituent orthogonal components of a wave. A quarter-wave plate (QWP) can introduce a π / 2 phase shift if correctly clocked with the incident light (e.g., at 45 degrees). A half-wave plate introduces a π phase shift.

[0055] A first reflective polarizer 524-1 is arranged such that a first lens 512-1 is located between a first waveplate 520-1 and the first reflective polarizer 524-1. For example, the first reflective polarizer 524-1 is on a first surface 528 of the first lens 512-1 or on a substrate separate from the first lens 512-1. A second reflective polarizer 524-2 is arranged such that a second lens 512-2 is located between a second waveplate 520-2 and the second reflective polarizer 524-2. For example, the second reflective polarizer 524-2 is on a fourth surface 540 of the second lens 512-2 or on a substrate separate from the second lens 512-2. In some embodiments, the first waveplate 520-1 and the second waveplate 520-2 are quarter-wave plates.

[0056] Figure 6A first path of light is depicted in an embodiment of the lens system. Light from display 504 passes through a first reflective polarizer 524-1, a first lens 512-1, a first waveplate 520-1, a partial reflector 516, a second waveplate 520-2, and a second lens 512-2, and is reflected by the second reflective polarizer 524-2. After being reflected from the second reflective polarizer 524-2, the light returns through the second waveplate 520-2 and is reflected by the partial reflector 516 (e.g., with some loss). After being reflected from the partial reflector 516, the light passes through the second waveplate 520-2 and through the second reflective polarizer 524-2 to the user's eye.

[0057] In some embodiments, a first reflective polarizer 524-1 is arranged to transmit p-polarized light (light polarized in the x-direction) and reflect s-polarized light (light polarized in the y-direction). A waveplate 520 is a quarter-waveplate and is oriented at 45 degrees relative to the x-axis. A second reflective polarizer 524-2 is arranged to transmit p-polarized light and reflect s-polarized light (e.g., at the same clock angle as the first reflective polarizer 524-1). A partial reflector 516 is a 50 / 50 mirror. Variations can be made to the illustrated embodiments(s). For example, the reflective polarizer 524 can be arranged (e.g., oriented) to allow s-polarized light to pass through, and / or the waveplate 520 can be arranged at 45 degrees or 135 degrees relative to the x-axis. In another example, the fast axis of the waveplate 520 can be a 90-degree clock angle, and the transmission axis of the reflective polarizer 524 can be a 90-degree clock angle.

[0058] Figure 7 An embodiment of a second path of light in a lens system is depicted. Light from display 504 passes through a first reflective polarizer 524-1, a first lens 512-1, a first waveplate 520-1, and is reflected by a partial reflector 516. The light reflected by the partial reflector 516 travels through the first waveplate 520-1, through the first lens 512-1, and is reflected by the first reflective polarizer 524-1. The light reflected by the first reflective polarizer 524-1 travels through the first lens 512-1, the first waveplate 520-1, the partial reflector 516 (e.g., with some loss), the second waveplate 520-2, the second lens 512-2, and the second reflective polarizer 524-2.

[0059] Figure 8 It is the first path in an embodiment of the lens system (e.g., Figure 6 The ray tracing diagram shown in the image. Figure 8A display 504, a viewing window 508, a first lens 512-1, and a second lens 512-2 are depicted. The first lens 512-1 is joined to the second lens 512-2 via a first waveplate, a partial reflector, and a second waveplate sandwiched between the first lens 512-1 and the second lens 512-2. The first waveplate is joined to the first lens 512-1. The second waveplate is joined to the second lens 512-2. The first waveplate and the second waveplate are joined to a partial reflector. A first reflective polarizer is located on the first lens 512-1 (e.g., on a curved surface of the first lens 512-1). A second reflective polarizer is located on the second lens 512-2 (e.g., on a curved surface of the second lens 512-2).

[0060] Figure 9 This is the second path in an embodiment of the lens system (e.g., Figure 7 The ray tracing diagram shown in the image. Figure 9 The image depicts a display 504, a viewing window 508, a first lens 512-1, and a second lens 512-2. The first lens 512-1 is attached to the second lens 512-2 via a first waveplate, a partial reflector, and a second waveplate sandwiched between the first lens 512-1 and the second lens 512-2. The first waveplate is attached to the first lens 512-1. The second waveplate is attached to the second lens 512-2. The first waveplate and the second waveplate are attached to the partial reflector. A first reflective polarizer is located on the first lens 512-1 (e.g., on a curved surface of the first lens 512-1). A second reflective polarizer is located on the second lens 512-2 (e.g., on a curved surface of the second lens 512-2).

[0061] Figure 10 It is the first path in an embodiment of the lens system (e.g., Figure 8 (as shown) and the second path (e.g., Figure 9 (As shown in the image) Ray tracing diagrams of the two. Figure 10 The image depicts a display 504, a viewing window 508, a first lens 512-1, and a second lens 512-2. The first lens 512-1 is attached to the second lens 512-2 via a first waveplate, a partial reflector, and a second waveplate sandwiched between the first lens 512-1 and the second lens 512-2. The first waveplate is attached to the first lens 512-1. The second waveplate is attached to the second lens 512-2. The first waveplate and the second waveplate are attached to the partial reflector. A first reflective polarizer is located on the first lens 512-1 (e.g., on a curved surface of the first lens 512-1). A second reflective polarizer is located on the second lens 512-2 (e.g., on a curved surface of the second lens 512-2).

[0062] Figure 11A flowchart depicts an embodiment of process 1100 for using foldable optics in a head-mounted display. Process 1100 begins at step 1104, where light from the display is transmitted through a first reflective polarizer and a first lens. For example, in Figure 6 The light is transmitted from the display 504 through the first reflective polarizer 524-1 and the first lens 512-1.

[0063] In step 1108, light from the first lens is transmitted, passing through the first waveplate and to the partial reflector. For example, in Figure 6 The light from the first lens 512-1 is transmitted to the first waveplate 520-1 and then to the partial reflector 516.

[0064] In step 1112, light is transmitted through a partial reflector, through a second waveplate, and through a second lens. For example, a portion of the light (e.g., a first portion) is transmitted through partial reflector 516, through second waveplate 520-2, and through second lens 512-2, as shown. Figure 6 As shown.

[0065] In step 1116, the light is reflected by the second reflective polarizer, returns through the second waveplate, and returns to the partial reflector. For example, in Figure 6 A portion (e.g., a first portion) of the light transmitted through partial reflector 516 is reflected by second reflective polarizer 524-2 to pass through second waveplate 520-2 in the negative z direction and reach partial reflector 516.

[0066] In step 1120, a portion of the light reflected by the reflective polarizer passes (e.g., a third time) through the second waveplate, through the second lens, reflected back to the second reflective polarizer, and passes through the second reflective polarizer. The portion of the light reflected by the reflective polarizer can be a second portion of the light, which is equal to the first portion minus the light transmitted (and / or absorbed) by the partial reflector. For example, Figure 6 Partial reflector 516 partially reflects right-handed circularly polarized light so that it (for the third time) passes through the second waveplate 520-2, the second lens 512-2, and the second reflective polarizer 524-2, as shown. Figure 6 As shown.

[0067] Figure 6 and Figure 11 It describes how light is reflected by a second reflective polarizer to a partial reflector, and how light from the partial reflector is reflected through a second lens and then through the second reflective polarizer.

[0068] Figure 12A flowchart depicts another embodiment of process 1200 for using foldable optics in a head-mounted display. Process 1200 begins at step 1204, where light from the display is transmitted through a first reflective polarizer and a first lens. For example, in Figure 7 The light is transmitted from the display 504 through the first reflective polarizer 524-1 and the first lens 512-1.

[0069] In step 1208, light from the first lens is transmitted, passing through the first waveplate and to the partial reflector. For example, in Figure 7 The light from the first lens 512-1 is transmitted through the first waveplate 520-1 and then to the partial reflector 516.

[0070] In step 1212, a portion of the light is reflected by a partial reflector to return through the first waveplate, the first lens, and to the first reflective polarizer. For example, in Figure 7 The light is reflected by partial reflector 516 (e.g., the third part, where for a 50 / 50 mirror, the third part is equal in size to the light reflected by the third part). Figure 11 In step 1112, the transmission passes through the first part of the reflective polarizer to pass through the first waveplate 520-1 and the first lens 512-1 in the negative z direction.

[0071] In step 1216, light is reflected by the first reflective polarizer to pass through the first lens, the first waveplate, and reach the partial reflector. For example, s-polarized light is reflected by the first reflective polarizer 524-1 to pass through the first waveplate 520-1 in the positive z-direction, and the light passing through the first waveplate 520-1 is transmitted to the partial reflector 516, as shown below. Figure 7 As shown.

[0072] In step 1220, a portion of the light (e.g., the fourth portion) is transmitted through a partial reflector, through a second waveplate, through a second lens, to a second reflective polarizer, and through the second reflective polarizer. For example, in Figure 7 The left-hand circularly polarized light passing through the partial reflector 516 is transmitted through the second waveplate 520-2 and the second lens 512-2, and then to the second reflective polarizer 524-2.

[0073] Figure 7 and Figure 12 It describes a process in which light from a partial reflector is reflected from a partial reflector to a first reflective polarizer before being transmitted through a second waveplate, and then reflected by the first reflective polarizer.

[0074] Those skilled in the art will recognize that, Figure 11 The process 1100 can be compared with Figure 12 The process 1200 is executed simultaneously.

[0075] The various features described herein (e.g., methods, apparatus, computer-readable media, etc.) can be implemented using combinations of dedicated components, programmable processors, and / or other programmable devices. The processes described herein can be implemented on the same processor or different processors. Where a component is described as being configured to perform certain operations, such configuration can be implemented, for example, by designing electronic circuits to perform the operations, by programming programmable electronic circuits (such as microprocessors) to perform the operations, or a combination thereof. Furthermore, while the embodiments described above may refer to specific hardware and software components, those skilled in the art will understand that different combinations of hardware and / or software components can also be used, and specific operations described as implemented in hardware can be implemented in software and vice versa.

[0076] Specific details are set forth in the above description to provide an understanding of the embodiments. However, it should be understood that the embodiments may be practiced without these specific details. In some cases, well-known circuits, processes, algorithms, structures, and techniques have been shown without unnecessary details to avoid obscuring the embodiments.

[0077] While the principles of this disclosure have been described above in conjunction with specific apparatus and methods, it should be understood that this description is by way of example only and not intended to limit the scope of this disclosure. The embodiments were chosen and described to explain the principles and practical application, enabling others skilled in the art to utilize the invention and make various modifications in the various embodiments as suitably suited to the particular purpose contemplated. It should be understood that this description is intended to cover modifications and equivalents.

[0078] Furthermore, it should be noted that an embodiment can be described as a process, which can be drawn as a flowchart, flow diagram, data flow diagram, structure diagram, or block diagram. Although a flowchart can describe operations as a continuous process, many operations can be performed in parallel or simultaneously. Moreover, the order of operations can be rearranged. A process terminates when its operations are completed, but may have additional steps not included in the diagram. A process can correspond to a method, function, process, subroutine, subroutine, etc.

[0079] The use of “a / an” or “the” is intended to mean “one or more” unless specifically indicated otherwise. All patents, patent applications, publications, and descriptions mentioned herein are incorporated herein by reference in their entirety for all purposes. Nothing in this document is to be considered prior art.

[0080] Specific details of a particular embodiment may be combined in any suitable manner without departing from the spirit and scope of the embodiments of the invention. However, other embodiments of the invention may relate to specific embodiments associated with each individual aspect, or a particular combination of these individual aspects.

[0081] The above description has been presented for purposes of illustration and description. It is not intended to be exhaustive, nor is it intended to limit the invention to the precise forms described, and many modifications and variations are possible in light of the teachings above. Embodiments were chosen and described to explain the principles of the invention and its practical application, thereby enabling others skilled in the art to utilize the invention in various embodiments as suitably suited to the particular purpose contemplated.

Claims

1. An apparatus for a foldable optics device in a head-mounted display, the apparatus comprising: Display for virtual reality devices; A lens system, arranged to focus light from the display onto the eyes of a user of the virtual reality device, the lens system comprising: First lens, wherein: The first lens has a first surface and a second surface; The second surface is opposite to the first surface; The first surface is curved; The first lens has a first thickness profile; and The first thickness profile is measured between the first surface and the second surface of the first lens; and The second lens, wherein: The second lens has a third surface and a fourth surface; The fourth surface is opposite to the third surface; The fourth surface is curved; The second lens has a second thickness profile; The second thickness profile is measured between the third surface and the fourth surface; The second thickness profile is the same as the first thickness profile; and The second lens is arranged symmetrically with respect to the first lens, such that the third surface is closer to the second surface than the surface closest to the first surface, and the second surface is closer to the third surface than the surface closest to the fourth surface; A partial reflector, the partial reflector being located between the first lens and the second lens; A first waveplate is located between the partial reflector and the first lens, wherein: The first waveplate is a quarter-wave plate; and The first waveplate adheres to the second surface of the first lens; A second waveplate, located between the partial reflector and the second lens, wherein: The second waveplate is a quarter-wave plate; and The second waveplate has a fast axis parallel to the fast axis of the first waveplate, such that the fast axis of the second waveplate is oriented in a direction similar to the fast axis of the first waveplate; A first reflective polarizer is located on the first surface of the first surface, and the first reflective polarizer is arranged such that the first lens is positioned between the first waveplate and the first reflective polarizer; and A second reflective polarizer is located on the fourth surface of the second lens, and the second reflective polarizer is arranged such that the second lens is located between the second waveplate and the second reflective polarizer.

2. The apparatus according to claim 1, characterized in that: The second surface of the first lens and the third surface of the second lens are flat; and The first thickness profile corresponds to the plano-convex lens.

3. An apparatus for a foldable optics device in a head-mounted display, the apparatus comprising: monitor; A lens system, arranged to focus light from the display onto a user's eye, the lens system comprising: First lens, wherein: The first lens has a first surface and a second surface; The second surface is opposite to the first surface; The first surface is curved; The first lens has a first thickness profile; and The first thickness profile is measured between the first surface and the second surface of the first lens; and The second lens, wherein: The second lens has a third surface and a fourth surface; The fourth surface is opposite to the third surface; The fourth surface is curved; The second lens has a second thickness profile; The second thickness profile is measured between the third surface and the fourth surface; The second thickness profile is the same as the first thickness profile; and The second lens is arranged symmetrically with respect to the first lens, such that the third surface is closer to the second surface than the surface closest to the first surface, and the second surface is closer to the third surface than the surface closest to the fourth surface; A partial reflector, the partial reflector being located between the first lens and the second lens; A first waveplate is located between the partial reflector and the first lens; A second waveplate is located between the partial reflector and the second lens; A first reflective polarizer, the first reflective polarizer being arranged such that the first lens is located between the first waveplate and the first reflective polarizer; and A second reflective polarizer is arranged such that the second lens is located between the second waveplate and the second reflective polarizer.

4. The apparatus according to claim 3, characterized in that, The first thickness profile corresponds to the plano-convex lens.

5. The apparatus according to claim 3, characterized in that: The first reflective polarizer is on the first surface; and The second reflective polarizer is located on the fourth surface.

6. The apparatus according to claim 3, characterized in that, The first waveplate and the second waveplate are quarter-wave plates.

7. The apparatus according to claim 3, characterized in that, The fast axis of the first waveplate and the fast axis of the second waveplate are oriented in similar directions.

8. The apparatus according to claim 3, characterized in that, The second surface of the first lens and the third surface of the second lens are flat.

9. The apparatus according to claim 3, characterized in that: The first waveplate is bonded to the first lens; The second waveplate is bonded to the second lens; The first waveplate is coupled to the partial reflector; and The second waveplate is attached to the partial reflector.

10. The apparatus according to claim 3, characterized in that, The first waveplate, the second waveplate, and the partial reflector are flat.

11. The apparatus according to claim 3, characterized in that, The device is part of a virtual reality headset.

12. A method for using foldable optics in a head-mounted display, the method comprising: Light from the display is transmitted through a first reflective polarizer and a first lens, wherein: The first lens has a first surface and a second surface; The second surface is opposite to the first surface; The first surface is curved; The first lens has a first thickness profile; and The first thickness profile is measured between the first surface and the second surface of the first lens; The light from the first lens is transmitted through the first waveplate and to the partial reflector, wherein: The first waveplate is located between the partial reflector and the first lens; and The first lens is located between the first waveplate and the first reflective polarizer; The light from the partial reflector is transmitted through the second waveplate and to the second lens, wherein: The partial reflector is located between the first lens and the second lens; The second waveplate is located between the partial reflector and the second lens; The second lens has a third surface and a fourth surface; The fourth surface is opposite to the third surface; The fourth surface is curved; The second lens has a second thickness profile; The second thickness profile is measured between the third surface and the fourth surface; The second thickness profile is the same as the first thickness profile; and The second lens is arranged symmetrically with respect to the first lens, such that the third surface is closer to the second surface than the surface near the first surface, and the second surface is closer to the third surface than the surface near the fourth surface; and Light is transmitted through the second lens and to the second reflective polarizer, wherein the second lens is located between the second waveplate and the second reflective polarizer.

13. The method according to claim 12, characterized in that, The first thickness profile corresponds to the plano-convex lens.

14. The method according to claim 12, characterized in that: The first reflective polarizer is on the first surface; and The second reflective polarizer is located on the fourth surface.

15. The method according to claim 12, characterized in that, The first waveplate and the second waveplate are quarter-wave plates.

16. The method according to claim 12, characterized in that, The fast axis of the first waveplate and the fast axis of the second waveplate are oriented in similar directions.

17. The method according to claim 12, characterized in that, The second surface of the first lens and the third surface of the second lens are flat.

18. The method according to claim 12, characterized in that: The first waveplate is bonded to the first lens; The second waveplate is bonded to the second lens; The first waveplate is coupled to the partial reflector; and The second waveplate is attached to the partial reflector.

19. The method of claim 12, further comprising reflecting the light from the partial reflector to the first reflective polarizer before transmitting the light from the partial reflector through the second waveplate, and using the first reflective polarizer to reflect the light.

20. The method of claim 12, further comprising: The second reflective polarizer is used to reflect light to the partial reflector; as well as The light from the partial reflector is reflected through the second lens and then through the second reflective polarizer.

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