Flexible optics for head-mounted displays

Abstract

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 lens and the second lens. 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. The reflective polarizer lies on the curved surfaces of the first and second lenses.

Description

Technical Field

[0001]

[0001] Cross - reference to Related Applications This application claims the benefit of U.S. Provisional Patent Application No. 63 / 490 ,170, filed on March 14, 2023, the entire content of which is hereby incorporated by reference in its entirety for all purposes.

Background Art

[0002]

[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 that, when worn, fixes at least one electronic display within at least one visible region 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 view (or actual reality) in front of the user with a "virtual" reality. HMDs for augmented reality (AR) can provide a translucent or transparent overlay of one or more screens in front of the wearer's eyes so that the actual view is augmented with additional information. In some AR devices, the "display" component of the HMD is transparent or is at the periphery of the user's field of view so as not to completely block the user's ability to see the external environment. In some AR devices, the display overlays digital content onto a video feed from a camera that acquires an image of the 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

Means for Solving the Problems

[0003]

[0003] Lens systems for head-mounted displays are used to focus light from the display onto the 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 lens and the second lens. 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. Reflecting polarizers may be located on the curved surfaces of the first and second lenses. The second lens may have the same shape as the first lens.

[0004]

[0004] In some configurations, the apparatus for a bent optical system in a head-mounted display comprises a display and a lens system. The lens system is arranged to focus light from the display onto the user's eyes. The lens system comprises a first lens having 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 and second surfaces of the first lens, and a second lens having a third surface and a fourth surface, the fourth surface being 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, and the second thickness profile being the first thickness profile The second lens is the same as the first lens, and is symmetrically positioned with respect to the first lens such that the third surface is 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 between the first lens and the second lens; a first waveplate between the partial reflector and the first lens; a second waveplate between the partial reflector and the second lens; a first reflective polarizer positioned such that the first lens is between the first waveplate and the first reflective polarizer; and / or a second reflective polarizer positioned such that the second lens is between the second waveplate and the second reflective polarizer.

[0005]

[0005] In some embodiments, the first thickness profile corresponds to a plano-convex lens, the first reflective polarizer is on the first surface; the second reflective polarizer is on the fourth surface; the first and second waveplates are quarter-waveplates; the high-speed axis of the first waveplate and the high-speed axis of the second waveplate are oriented in the same direction; the second surface of the first lens and the third surface of the second lens are flat; the first waveplate is bonded to the first lens; the second waveplate is bonded to the second lens; the first waveplate is bonded to a partial reflector; the second waveplate is bonded 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]

[0006] In some configurations, a method for using a bent optical system in a head-mounted display is a method of transmitting light from a 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 facing the first surface, the first surface is curved, the first lens has a first thickness profile, and / or the first thickness profile is measured between the first surface and the second surface of the first lens; transmitting light from the first lens to a partial reflector through a first waveplate, wherein the first waveplate is between the partial reflector and the first lens, and / or the first lens is between the first waveplate and the first reflective polarizer; and transmitting light from the partial reflector to a second lens through a second waveplate. Steps include: a step in which a partial reflector is located between a first lens and a second lens, a second waveplate is located between the partial reflector and the second lens, the second lens having a third surface and a fourth surface, the fourth surface facing 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 surface and the fourth surface, the second thickness profile being the same as the first thickness profile, and the second lens being symmetrically positioned with respect to the first lens such that the third surface is closer to the second surface than the first surface, and / or the second surface is closer to the third surface than the fourth surface; and transmitting light through the second lens to a second reflective polarizer, the second lens being located between the second waveplate and the second reflective polarizer.

[0007]

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

[0008]

[0008] Further areas of application of this disclosure will become apparent from the detailed description provided below. The detailed description and specific examples illustrate various embodiments, but should be understood to be illustrative only and not necessarily limiting the scope of this disclosure.

[0009]

[0009] This disclosure will be explained in conjunction with the attached drawings. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram of one embodiment of a network environment for a head-mounted display (HMD). [Figure 2] This figure shows one embodiment of an environment for using an HMD. [Figure 3] This is a front view of one embodiment of an HMD having a binocular display subsystem. [Figure 4] This is a top view of one embodiment of an HMD having a binocular display subsystem and various sensors. [Figure 5] This is an exploded view of one embodiment of a lens system using a bent optical system. [Figure 6] This figure shows one embodiment of the first path of light in a lens system. [Figure 7] This figure shows one embodiment of the second path of light in a lens system. [Figure 8] This is a ray tracing diagram of one embodiment of the first light path in a lens system. [Figure 9] This is a ray tracing diagram of one embodiment of the second light path in a lens system. [Figure 10] This is a ray tracing diagram of one embodiment of the first and second paths of light in a lens system. [Figure 11] This is a flowchart of one embodiment of a process for using a bent optical system in a head-mounted display. [Figure 12]This is a flowchart of another embodiment of the process for using a bent optical system in a head-mounted display. [Modes for carrying out the invention]

[0011]

[0022] In the accompanying drawings, similar components and / or features may have the same reference label. Furthermore, various components of the same type may be distinguished by following the reference label with a dash and a second label that distinguishes similar components. Where only the first reference label is used herein, the description is applicable to any similar component having the same first reference label, regardless of the second reference label.

[0012]

[0023] The following description provides only preferred exemplary embodiments and is not intended to limit the scope, applicability, or configuration of the Disclosure. Rather, the following description of preferred exemplary embodiments provides a possible description for carrying out the preferred exemplary embodiments to those skilled in the art. It will be understood that various modifications can be made to the function and arrangement of the elements without departing from the spirit and scope set forth in the appended claims.

[0013]

[0024] Bent optical systems can be used to bend the optical path to reduce the form factor of the lens system. An example of a bent optical system in a head-mounted display is a pancake lens. Some pancake lenses have an efficiency limit of 25% because light is incident on the partial mirror twice. In some embodiments, a reflective polarizer is used in the lens system to recapture some of the light reflected by the partial mirror. The theoretical loss of a lens system (e.g., using a bent optical system and a reflective polarizer) is 50% in some embodiments.

[0014]

[0025] For illustrative purposes, several embodiments are described below in which a particular type of information is obtained and used by using a particular type of device in a particular type of manner for a particular type of structure. However, it will be understood that such described techniques may be used in other ways in other embodiments, and therefore this disclosure is not limited to the illustrative details provided. As a non-exclusive example, some embodiments involve the use of images that are video frames. While the examples may refer to “video frames” for convenience, it will be understood that the techniques described in the examples may be employed with respect to one or more images of various types, including non-exclusive examples of multiple consecutive video frames (e.g., 30, 60, 90, 180, or other frame counts), other video content, photographs, computer-generated graphic content, articles of other visual media, or any combination thereof. Furthermore, various details are provided in the drawings and descriptions for illustrative purposes and are not intended to limit the scope of this disclosure.

[0015]

[0026] FIG. 1 is a schematic diagram of an embodiment of a network environment 100. The network environment 100 includes a local media rendering (LMR) system 110 (e.g., a game system), which includes a local computing system 120 and a display device 180 (e.g., an HMD device having two display panels). In FIG. 1, the local computing system 120 is communicatively connected to the display device 180 via a transmission link 115 (the transmission link 115 may be wired or tethered via one or more cables (cable 220) as shown in FIG. 2, or may be wireless). In some embodiments, the local computing system 120 may provide encoded image data for display to a panel display device (e.g., a TV, console, or monitor) via a wired or wireless link in addition to, or instead of, the HMD device 180, and each display device includes one or more addressable pixel arrays. In some embodiments, the local computing system 120 may include a general-purpose computing system, a game console, a video stream processing device, a mobile computing device (e.g., a mobile phone, PDA, or other mobile device), a VR or AR processing device, or other computing systems.

[0016]

[0027] A pixel is the smallest addressable image element of a display that can be activated to provide a color value. In some cases, a pixel uses separate color channels that encode pixel values of different color sub-pixels to generate red, green, and blue light separately for perception by a human observer, including individual sub-elements (in some cases separate "sub-pixels"). Pixel values refer to data values corresponding to the respective levels of stimulation for one or more of the respective RGB elements of a single pixel.

[0017]

[0028] In FIG. 1, the local computing system 120 includes components having one or more hardware processors (e.g., a central processing unit, or "CPU") 125, a memory 130, various I / O ("input / output") hardware components 127 (e.g., a keyboard, a mouse, one or more game controllers, speakers, microphones, IR transmitter and / or receiver, 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. One embodiment of the eye tracking subsystem 135 is executed within the memory 130 to perform one or more processes, such as by using the CPU 125 and / or the GPU 144 to perform automated operations. The memory 130 may optionally further execute one or more other programs 133 (e.g., to generate a displayed video or other image such as a game program). As part of the automated operations, the program 133 executed by the eye tracking subsystem 135 and / or the memory 130 can store or retrieve various types of data, including an exemplary database data structure of the storage device 150. In this example, the data used may include various types of image data information 154 within a database ("DB"), various types of application data 152 within the DB, various types of configuration data 157 within the DB, or may include additional information such as system data or other information.

[0018]

[0029] The LMR system 110 is communicably connected via one or more computer networks 101 and network links 102 to an exemplary network-accessible media content provider 190 that can provide content to the LMR system 110 for display, in addition to or instead of the image generation program 133. The media content provider 190 may include one or more computing systems (not shown) each having components similar to those of the local computing system 120, including one or more hardware processors, I / O components, local storage devices, and memory, but for brevity, some details of the network-accessible media content provider are not shown.

[0019]

[0030] Although the display device 180 is shown as separate and independent from the local computing system 120 in Figure 1, it will be understood that in some embodiments, some or all components of the local media rendering system 110 may be integrated or housed within a single device such as a mobile game device, a portable VR entertainment system, or an HMD device. In some embodiments, the transmit link 115 may include, for example, one or more system bus and / or video bus architectures.

[0020]

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

[0021]

[0032] It will also be understood that the computing system 120 and the display device 180 are merely illustrative and are not intended to limit the scope of this disclosure. The computing system 120 may instead include multiple interacting computing systems or devices and may be connected to other devices not shown via one or more networks such as the Internet, via the Web, or via a private network (e.g., a mobile communications network). More generally, the computing system or other computing node may include, but is not limited to, any combination of hardware or software capable of interacting with and performing functions of the described types, including desktops or other computers, game systems, database servers, network storage devices and other network devices, PDAs, mobile phones, wireless phones, pagers, electronic organizers, internet equipment, television-based systems (e.g., using set-top boxes and / or personal / digital video recorders), and various other consumer products including appropriate communication functions. The display device 180 may similarly include one or more devices having one or more display panels of various types and forms, and may optionally include various other hardware and / or software components.

[0022]

[0033] In addition, the functions provided by the eye-tracking subsystem 135 may, in some embodiments, be distributed across one or more components, and in some embodiments, some of the functions of the eye-tracking subsystem 135 may not be provided, and / or other additional functions may be available. Although various items are shown as being stored in memory or storage during use, it will also be understood that these items or some of the items may be transferred between memory and other storage devices for memory management or data integrity purposes. Thus, in some embodiments, the technology may be executed by one or more processors or other configured hardware circuits or hardware including memory or storage devices, such as when the technology is comprised of one or more software programs (e.g., by the eye-tracking subsystem 135 or its components) and / or data structures (e.g., by the execution of software instructions of one or more software programs, and / or by the storage of 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-temporary computer-readable storage media such as hard disks or flash drives or other non-volatile storage devices, volatile or non-volatile memory (e.g., RAM), network storage devices, or portable media articles read by a suitable drive (e.g., DVD discs, CD discs, optical discs, etc.) or via a suitable connection. The systems, components, and data structures may also be transmitted (e.g., as data signals generated on various computer-readable transmission media, including wireless-based and wired / cable-based media) in some embodiments (e.g., as part of a carrier wave or other analog or digital propagation signal), or in various forms (e.g., as part of a single or multiplexed analog signal, or as multiple individual digital packets or frames). Such computer program products may also take other forms in some embodiments.

[0023]

[0034] Figure 2 shows an embodiment of an environment 200 used with an exemplary HMD device 202 coupled to a video rendering computing system 204 via a tethering connection 220 (or a wireless connection in some embodiments) to provide a virtual reality display to a human user 206. The user wears the HMD device 202 and receives information displayed via the HMD device from the computing system 204 of a simulated environment distinct from the actual physical environment, and the computing system acts as an image rendering system that supplies images of the simulated environment to the HMD device to display to the user, such as images generated by game programs and / or other software programs running on the computing system. The user may further move within a tracked area 201 of the actual physical environment 200 in this example and may have one or more I / O ("input / output") devices to allow the user to further interact with the simulated environment, including handheld controllers 208 and 210 in this example.

[0024]

[0035] In the illustrated example, the environment 200 may include one or more base stations 214 (two labeled base stations 214a and 214b shown) that can facilitate tracking of the HMD device 202 or controllers 208 and 210. When the user moves or changes the orientation of the HMD device 202, the position of the HMD device is tracked, enabling, for example, a corresponding portion of the simulated environment to be displayed to the user on the HMD device, and controllers 208 and 210 may further employ similar techniques for use in tracking the position of the controllers (and optionally use that information to assist in determining or verifying the position of the HMD device). After the tracked position of the HMD device 202 is known, the corresponding information is transmitted to the computing system 204 via the tether 220 or wirelessly, and the tracked position information is used to generate one or more subsequent images of the simulated environment to be displayed to the user.

[0025]

[0036] There are many methods of position tracking 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.

[0026]

[0037] In some embodiments, the HMD device 202 includes one or more optical receivers or sensors that can be used to implement tracking functions or other aspects of the present disclosure. For example, each base station 214 may scan an optical signal across the area to be tracked 201. Depending on the requirements of each particular embodiment, each base station 214 may generate multiple optical signals. For example, a single base station 214 may be sufficient for six-degree-of-freedom tracking, but in some embodiments, multiple base stations (e.g., base stations 214a, 214b) may be used to provide robust room-scale tracking to the HMD device and / or peripherals. In this example, the optical receiver is incorporated into the HMD device 202 and / or other tracked objects such as controllers 208 and 210. In some embodiments, the optical receiver may be paired with an accelerometer and gyroscope inertial measurement unit ("IMU") on each device being tracked to support low-latency sensor fusion.

[0027]

[0038] In some embodiments, each base station 214 includes two rotors that scan a linear beam across the area to be tracked 201 on orthogonal axes. At the start of each scanning cycle, the base station 214 may emit an omnidirectional light pulse (called a “synchronization signal”) visible to sensors on the object to be tracked. Thus, each sensor calculates its unique angular position within the area to be scanned by timing the duration between the synchronization signal and the beam signal. Sensor distance and orientation may be resolved using multiple sensors mounted on a single rigid body.

[0028]

[0039] One or more sensors positioned on the object being tracked (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 appropriate amplifier / detector circuits may be used. Since the environment 200 may contain static and time-varying signals (optical noise) having wavelengths similar to the signals of the base station 214, in some embodiments the base station light may be modulated to facilitate distinction from interfering signals and / or to filter the sensors from radiation of any wavelength other than the wavelength of the base station signal.

[0029]

[0040] Inside-out tracking is also a type of position tracking that can be used to track the position of an HMD device 202 and / or other objects (e.g., controllers 208 and 210, tablet computers, smartphones). Inside-out tracking differs from outside-in tracking in that the camera or other sensor used to determine the HMD's position is located at a stationary position in the environment, while in outside-out tracking, the camera or sensor is located at a stationary position in the environment.

[0030]

[0041] HMDs utilizing inside-out tracking use one or more cameras to "look outside" to determine how their position changes relative to the environment. As the HMD moves, sensors readjust their position 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 the 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. With "markerless" inside-out tracking, the HMD system uses inherent characteristics of 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.

[0031]

[0042] Figure 3 shows information 300 illustrating a front view of an exemplary HMD device 344 when worn on the head of a user 342. The HMD device 344 includes a forward-facing structure 343 supporting a forward-facing or forward-facing camera 346 and one or more types of sensors 348a-348d (collectively 348). As an example, some or all of the sensors 348 may help determine the position and / or orientation of the device 344 in space, such as optical sensors for detecting and using light information emitted from one or more external devices (not shown, e.g., base station 214 in Figure 2). As shown, the forward-facing camera 346 and sensors 348 are oriented forward toward an actual scene or environment (not shown) in which the user 342 operates the HMD device 344. The actual physical environment may include, for example, one or more objects (e.g., a wall, ceiling, furniture, stairs, car, tree, tracking marker, or any other type of object). The particular number of sensors 348 may be less or more than the number of sensors shown. The HMD device 344 may further include one or more additional components not mounted in a forward-facing structure (e.g., inside the HMD device), such as an IMU (Inertial Measurement Unit) 347 electronic device that measures and reports specific forces, angular velocities, and / or magnetic fields surrounding the HMD device (e.g., using a combination of an accelerometer and a gyroscope, and optionally using a magnetometer). The HMD device may further include additional components not shown, including one or more display panels and optical lens systems that are oriented towards the user's eyes (not shown) and optionally have one or more mounted internal motors to change the alignment or other positioning of one or more optical lens systems and / or display panels within the HMD device, as will be described in more detail below with respect to Figure 4.

[0032]

[0043] An illustrated example of the HMD device 344 is supported on the head of a user 342, at least partially based on one or more straps 345 attached to the housing of the HMD device 344 and extending all or partially around the user's head. Not shown herein, the HMD device 344 may further have one or more external motors, such as one or more attached to one or more of the straps 345, and automatic compensation operations may include adjusting such straps using such motors to correct the alignment or other positioning of the HMD device on the user's head. In addition to the illustrated straps, or instead, the HMD device may include other support structures not shown herein (e.g., nosepiece, chin strap, etc.), and it will be understood that some embodiments may include motors attached to one or more such other support structures to adjust their shape and / or position as well to correct the alignment or other positioning of the HMD device on the user's head. Other display devices not attached to the user's head may similarly be attached to or be 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 to modify their shape and / or position to correct the alignment or other positioning of the display device with respect to one or more pupils of one or more users of the display device.

[0033]

[0044] Figure 4 shows a simplified top view 400 of one embodiment of an HMD device 405 including a pair of near-to-eye display systems 402 and 404. The HMD device 405 may be, for example, the same or similar HMD devices shown in Figures 1 to 3, or different HMD devices, and the HMD devices described herein may be used further in examples described below. The near-to-eye display systems 402 and 404 in Figure 4 each include a display panel 406 and 408 (e.g., an OLED microdisplay) and respective optical lens systems 410 and 412, each having one or more optical lenses. The display systems 402 and 404 may be mounted on or positioned within a housing (or frame) 414, which includes a forward-facing portion 416 (e.g., the same or similar as the forward-facing surface 343 in Figure 3), a left temple 418, a right temple 420, and an inner surface 421, which contact or are in close proximity to the face of the wearer user 424 when the HMD device is worn by the user. The two display systems 402 and 404 may be fixed to the housing 414 in an eyeglasses device that can be worn on the head 422 of the wearer user 424, with the left temple 418 and right temple 420 resting on the user's ears 426 and 428, respectively, and the nose assembly 492 resting on the user's nose 430. In the example of Figure 4, the HMD device 405 may be supported partially or entirely on the user's head by the nose display and / or the left and right over-ear temples, but in some embodiments, such as the embodiments shown in Figures 2 and 3, a strap (not shown) or other structure may be used to secure the HMD device to the user's head. The housing 414 can be shaped and sized such that each of the two optical lens systems 410 and 412 is positioned in front of one of the user's eyes 432 and 434, respectively, so that the target position of each pupil 494 is centered vertically and horizontally in front of their respective optical lens systems and / or display panels.Although the housing 414 is shown in a simplified manner similar to eyeglasses for illustrative purposes, it should be understood that in practice, more sophisticated structures (e.g., goggles, integrated headbands, helmets, straps, etc.) can be used to support and position the display systems 402 and 404 on the user's head 422.

[0034]

[0045] The HMD device 405 in Figure 4 is positioned to present a virtual reality display to the user, such as via corresponding video presented at a display rate of 30, 60, or 90 frames (or images) per second. In some embodiments, the HMD device may present an augmented reality display to the user. Each of the displays 406 and 408 in Figure 4 may generate light that passes through their respective optical lens systems 410 and 412 and is focused to the eyes 432 and 434 of the user 424, respectively. The pupil 494 opening of each eye, through which light passes and enters the eye, generally has a pupil size ranging from 2 mm in diameter in very bright conditions to up to 8 mm in dim conditions, although the larger iris containing the pupil can be about 12 mm in size, and the pupil (and the iris surrounding it) can move a few more millimeters horizontally and / or vertically within the visible portion of the eye under an open eyelid, and as the eyeball rotates around its center, different horizontal and vertical positions cause the pupil to move to different depths from the optical lens or other physical elements of the display (resulting in a three-dimensional area in which the pupil can move). The light entering the user's pupil is seen 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 and less than 20 mm), which has the advantage that the HMD device feels lighter to the user because the weight of the optical lens system and display system is relatively close to the user's face, and may also provide the user with a larger field of view. Some embodiments of the HMD device may include various additional internal and / or external sensors.

[0035]

[0046] In Figure 4, the HMD device 405 includes hardware sensors and additional components such as one or more accelerometers and / or gyroscopes 490 (for example, as part of one or more IMU units). Values ​​from one or more accelerometers and / or gyroscopes may be used to locally determine the orientation of the HMD device. In addition, the HMD device 405 may include one or more forward-facing cameras, such as an external camera 485 on the front 416, and the information therefrom may be used as part of the operation of the HMD device, such as to provide AR functions or positioning functions. Furthermore, the HMD device 405 may further include other components 475 (e.g., electronic circuits for controlling the display of images on display panels 406 and 408, internal memory, one or more batteries, position tracking devices for interacting with an external base station, etc.). Some embodiments may not include one or more of the components 475, 485, and / or 490. Some embodiments of HMD devices may include a variety of additional internal and / or external sensors for tracking various other types of movement and position, such as the user's body, eyes, and controllers.

[0036]

[0047] The HMD device 405 further includes hardware sensors and additional components that may be provided for use in one or more components associated with the HMD device, which may be used to determine the user's pupil or gaze direction. The hardware sensors include one or more eye-tracking assemblies 472 of the 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 use in obtaining information about the actual position of the user's pupils 494, such as separately for each pupil in this example.

[0037]

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

[0038]

[0049] Information from the eye-tracking assembly 472 may be used to determine and track the user's gaze direction while using the HMD device 405. Furthermore, in some embodiments, the HMD device 405 may include one or more internal motors 438 (or other moving mechanisms) that can be used to move one or more alignments and / or other positioning (e.g., vertical, horizontal left-right, and / or horizontal front-back) of the optical lens systems 410 and 412 and / or display panels 406 and 408 within the housing of the HMD device 405 (439), such as to individualize or otherwise adjust the target pupil positions of one or both of the near-to-eye display systems 402 and 404 to correspond to the actual positions of one or both pupils 494. Such motors 438 may be controlled, for example, by user operation of one or more control units 437 on the housing 414 and / or via user operation of one or more associated separate I / O controllers (not shown). In some embodiments, the HMD device 405 may 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, for example, by using an adjustable positioning mechanism (e.g., a screw, slider, ratchet, etc.) that is manually modified by the user via the use of a control unit 437. In Figure 4, the motor 438 is shown for only one of the near-to-eye display systems, but each near-to-eye display system may have its own one or more motors, and in some embodiments, one or more motors may be used to control each of the multiple near-to-eye display systems (e.g., independently).

[0039]

[0050] In some embodiments, a single optical lens and display device, or other types of display systems including multiple such optical lenses and display devices, may be used. Non-exclusive examples of other such devices include cameras, telescopes, microscopes, binoculars, spotting scopes, and surveying scopes. Furthermore, a wide variety of display panels or other display devices that emit light to form an image may be used, and one or more users view them through one or more optical lenses. In some embodiments, a user may view one or more images produced in a manner other than a display panel, such as on a surface that partially or entirely reflects light from another light source, through one or more optical lenses.

[0040]

[0051] Figure 5 is an exploded view of one embodiment of a lens system using a bent optical system for a head-mounted display. The lens system is arranged to focus light from a display 504 (e.g., a projector) onto the user's eyes (e.g., an eyebox 508). The lens system comprises 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.

[0041]

[0052] The first lens 512-1 has a first surface 528 and a second surface 532. The second surface 532 is opposite the first surface 528. The first surface 528 is curved (for example, to focus light from the display 504 to the eye box 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 dimension (for example, d-1 for the first lens 512-1, d-2 for the second lens 512-2) at a given position (e.g., x,y) of the lens 512.

[0042]

[0053] The second lens 512-2 has a third surface 536 and a fourth surface 540. The fourth surface 540 is opposite the third surface 536. The fourth surface 540 is curved (for example, to focus light from the display 504 to the eye box 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 (for example, in the z direction). The second thickness profile is the same as the first thickness profile (for example, d-1 = d-2 for each (x,y) of the lens 512). For example, the first thickness profile (and the second thickness profile) is for a plano-convex lens. The second lens 512-2 is positioned 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. By making the second lens 512-2 identical to the first lens 512-1 (e.g., having the same profile), it is possible to reduce the number of unique parts in the lens system and / or simplify manufacturing.

[0043]

[0054] The partial reflector 516 is located between the first lens 512-1 and the second lens 512-2. In some embodiments, the partial reflector 516 is a 50 / 50 mirror. The first waveplate 520-1 is located between the partial reflector 516 and the first lens 512-1. The 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 orthogonal components of a wave. A quarter-waveplate (QWP) introduces a π / 2 phase shift when appropriately rotated with the incident light (e.g., at 45 degrees). A half-waveplate introduces a π phase shift.

[0044]

[0055] The first reflective polarizer 524-1 is positioned such that the first lens 512-1 is between the first waveplate 520-1 and the first reflective polarizer 524-1. For example, the first reflective polarizer 524-1 is on the first surface 528 of the first lens 512-1 or on a substrate separate from the first lens 512-1. The second reflective polarizer 524-2 is positioned such that the second lens 512-2 is between the second waveplate 520-2 and the second reflective polarizer 524-2. For example, the second reflective polarizer 524-2 is on the 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.

[0045]

[0056] Figure 6 shows the first path of light in one embodiment of the lens system. Light from the display 504 passes through the first reflective polarizer 524-1, the first lens 512-1, the first waveplate 520-1, the partial reflector 516, the second waveplate 520-2, the 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 travels backward 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 the second reflective polarizer 524-2 to reach the user's eye.

[0046]

[0057] In some embodiments, the first reflective polarizer 524-1 is positioned to transmit p-polarized light (light polarized in the x-direction) and reflect s-polarized light (light polarized in the y-direction). The waveplate 520 is a quarter-wave plate and is oriented at 45 degrees with respect to the x-axis. The second reflective polarizer 524-2 is positioned to transmit p-polarized light and reflect s-polarized light (e.g., rotated to the same angle as the first reflective polarizer 524-1). The partial reflector 516 is a 50 / 50 mirror. Variations from the embodiments shown can be made. For example, the reflective polarizer 524 may be positioned (e.g., oriented) to transmit s-polarized light, and / or the waveplate 520 may be positioned at 45 or 135 degrees from the x-axis. In another example, the fast axis of the waveplate 520 may be rotated by 90 degrees, and the transmission axis of the reflective polarizer 524 may be rotated by 90 degrees.

[0047]

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

[0048]

[0059] Figure 8 is a ray tracing diagram of a first path (for example, shown in Figure 6) in one embodiment of the lens system. Figure 8 shows a display 504, an eye box 508, a first lens 512-1, and a second lens 512-2. The first lens 512-1 is bonded to the second lens 512-2 with 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 bonded to the first lens 512-1. The second waveplate is bonded to the second lens 512-2. The first and second waveplates are bonded to the partial reflector. The first reflective polarizer is located on the first lens 512-1 (for example, on the curved surface of the first lens 512-1). The second reflecting polarizer is located on the second lens 512-2 (for example, on the curved surface of the second lens 512-2).

[0049]

[0060] Figure 9 is a ray tracing diagram of a second path (for example, shown in Figure 7) in one embodiment of the lens system. Figure 9 shows a display 504, an eyebox 508, a first lens 512-1, and a second lens 512-2. The first lens 512-1 is bonded to the second lens 512-2 with 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 bonded to the first lens 512-1. The second waveplate is bonded to the second lens 512-2. The first and second waveplates are bonded to the partial reflector. The first reflective polarizer is located on the first lens 512-1 (for example, on the curved surface of the first lens 512-1). The second reflecting polarizer is located on the second lens 512-2 (for example, on the curved surface of the second lens 512-2).

[0050]

[0061] Figure 10 shows ray tracing diagrams of both a first path (e.g., shown in Figure 8) and a second path (e.g., shown in Figure 9) in one embodiment of a lens system. Figure 10 shows a display 504, an eye box 508, a first lens 512-1, and a second lens 512-2. The first lens 512-1 is bonded to the second lens 512-2 with 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 bonded to the first lens 512-1. The second waveplate is bonded to the second lens 512-2. The first and second waveplates are bonded to the partial reflector. The first reflective polarizer is located on the first lens 512-1 (e.g., on the curved surface of the first lens 512-1). The second reflecting polarizer is located on the second lens 512-2 (for example, on the curved surface of the second lens 512-2).

[0051]

[0062] Figure 11 shows a flowchart of one embodiment of process 1100 for using a bent optical system in a head-mounted display. Process 1100 begins with step 1104, which transmits light from the display through a first reflective polarizer and a first lens. For example, light from the display 504 is transmitted through the first reflective polarizer 524-1 and the first lens 512-1 in Figure 6.

[0052]

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

[0053]

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

[0054]

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

[0055]

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

[0056]

[0067] Figures 6 and 11 illustrate how a second reflective polarizer reflects light to a partial reflector, and how light from the partial reflector is reflected through a second lens and a second reflective polarizer.

[0057]

[0068] Figure 12 shows a flowchart of another embodiment of process 1200 for using a bent optical system in a head-mounted display. Process 1200 begins with step 1204, which transmits light from the display through a first reflective polarizer and a first lens. For example, light from the display 504 passes through the first reflective polarizer 524-1 and the first lens 512-1 in Figure 7.

[0058]

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

[0059]

[0070] In step 1212, a portion of the light is reflected by the partial reflector and returns to the first reflecting polarizer through the first waveplate and the first lens. For example, the light is reflected by the partial reflector 516 in Figure 7 (for example, a third portion equal in size to the first portion that passed through the reflecting polarizer in step 1112 of Figure 11 for a 50 / 50 mirror) and passes through the first waveplate 520-1 and the first lens 512-1 in the negative z direction.

[0060]

[0071] In step 1216, the light is reflected by the first reflecting polarizer, passes through the first lens and the first waveplate, and reaches the partial reflector. For example, as shown in Figure 7, the s-polarized light is reflected by the first reflecting polarizer 524-1 and passes through the first waveplate 520-1 in the positive z direction, and the light that has passed through the first waveplate 520-1 is transmitted to the partial reflector 516.

[0061]

[0072] In step 1220, a portion of the light (for example, the fourth portion) passes through the partial reflector, the second waveplate, and the second lens to reach the second reflecting polarizer and then passes through the second reflecting polarizer. For example, left-hand circularly polarized light that has passed through the partial reflector 516 in Figure 7 passes through the second waveplate 520-2 and the second lens 512-2 to reach the second reflecting polarizer and then passes through the second reflecting polarizer 524-2.

[0062]

[0073] Figures 7 and 12 illustrate the process of reflecting light from the partial reflector to the first reflecting polarizer before transmitting the light from the partial reflector through the second waveplate, and then reflecting the light from the first reflecting polarizer.

[0063]

[0074] Those skilled in the art will recognize that process 1100 in Figure 11 can be performed simultaneously with process 1200 in Figure 12.

[0064]

[0075] Various features described herein, such as 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 carried out on the same processor or different processors. Where a component is described as being configured to perform a particular operation, such configuration can be achieved, for example, by designing an electronic circuit to perform the operation, by programming a programmable electronic circuit (such as a microprocessor) to perform the operation, or by a combination thereof. Furthermore, while the embodiments described above may refer to specific hardware and software components, different combinations of hardware and / or software components can also be used, and it will be understood by those skilled in the art that a particular operation described as being implemented in hardware can be implemented in software, and vice versa.

[0065]

[0076] The above description provides specific details to help understand the embodiments. However, it is understood that embodiments may be carried out without these specific details. In some examples, well-known circuits, processes, algorithms, structures, and techniques may be shown without unnecessary details to avoid obscuring the embodiments.

[0066]

[0077] While the principles of this disclosure are described above in relation to specific apparatuses and methods, it should be understood that this description is provided only as an example and not as a limitation on the scope of this disclosure. Embodiments have been selected and described to clarify the principles and practical applications so that those skilled in the art can utilize the invention with various modifications in various embodiments to suit the specific application intended. It should be understood that the description is intended to cover modifications and equivalents.

[0067]

[0078] Furthermore, it should be noted that embodiments may be described as processes shown as flowcharts, flow diagrams, data flow diagrams, structural diagrams, or block diagrams. While flowcharts may describe operations as sequential processes, many operations can be performed in parallel or simultaneously. In addition, the order of operations may be rearranged. A process terminates when its operations are completed, but it may have additional steps not shown in the diagram. A process can correspond to a method, function, procedure, subroutine, subprogram, etc.

[0068]

[0079] The enumerations of “a,” “an,” or “the” are intended to mean “one or more” unless otherwise specified. Patents, patent applications, publications, and specifications referenced herein are incorporated in their entirety by reference for all purposes. There is no prior art to be recognized.

[0069]

[0080] Certain details of a particular embodiment may be combined in any suitable manner without departing from the spirit and scope of the embodiments of the present invention. However, other embodiments of the present invention may cover specific embodiments relating to each individual aspect, or specific combinations of these individual aspects.

[0070]

[0081] The above description is presented for illustrative and explanatory purposes only. It is not intended to be exhaustive or to limit the invention to the exact forms described, and many modifications and variations are possible in light of the above teachings. The embodiments have been selected and described to illustrate the principles of the invention and its practical applications, thereby enabling those skilled in the art to utilize the invention in various embodiments with various modifications suitable for the specific applications intended.

Claims

1. An apparatus for a bent optical system in a head-mounted display, wherein the apparatus is The display of the virtual reality device, A lens system configured to focus light from the display onto the eyes of the user of the virtual reality device, The lens system is equipped with, The first lens, 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, The first thickness profile is measured between the first surface and the second surface of the first lens. The first lens and, The second lens, The second lens has a third surface and a fourth surface, The fourth surface is opposite 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. The second lens is positioned symmetrically with respect to the first lens such that the third surface is closer to the second surface than the first surface, and the second surface is closer to the third surface than the fourth surface. The second lens, A partial reflector between the first lens and the second lens, A first waveplate between the partial reflector and the first lens, The first waveplate is a quarter waveplate, The first waveplate is bonded to the second surface of the first lens. The first waveplate and A second waveplate between the partial reflector and the second lens, The second waveplate is a quarter-wave plate, The second waveplate has a high-speed axis parallel to the high-speed axis of the first waveplate, such that the high-speed axis of the second waveplate is oriented in the same direction as the high-speed axis of the first waveplate. The second waveplate and A first reflective polarizer is located on the first surface of the first lens and is positioned such that the first lens is between the first waveplate and the first reflective polarizer, A second reflective polarizer is located on the fourth surface of the second lens and is positioned such that the second lens is between the second waveplate and the second reflective polarizer, Equipped with, Device.

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

3. An apparatus for a bent optical system in a head-mounted display, wherein the apparatus is The display and A lens system configured to focus the light from the display towards the user's eyes, The lens system is equipped with, The first lens, 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, The first thickness profile is measured between the first surface and the second surface of the first lens. The first lens and, The second lens, The second lens has a third surface and a fourth surface, The fourth surface is opposite 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. The second lens is positioned symmetrically with respect to the first lens such that the third surface is closer to the second surface than the first surface, and the second surface is closer to the third surface than the fourth surface. The second lens, A partial reflector between the first lens and the second lens, A first waveplate between the partial reflector and the first lens, A second waveplate between the partial reflector and the second lens, A first reflective polarizer is arranged such that the first lens is between the first waveplate and the first reflective polarizer, A second reflective polarizer is arranged such that the second lens is between the second waveplate and the second reflective polarizer, Equipped with, Device.

4. The apparatus according to claim 3, wherein the first thickness profile corresponds to a plano-convex lens.

5. The first reflective polarizer is located on the first surface, The second reflecting polarizer is located on the fourth surface, The apparatus according to claim 3.

6. The apparatus according to claim 3, wherein the first waveplate and the second waveplate are quarter-waveplates.

7. The apparatus according to claim 3, wherein the high-speed axis of the first waveplate and the high-speed axis of the second waveplate are oriented in the same direction.

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

9. The first waveplate is joined to the first lens, The second waveplate is joined to the second lens, The first waveplate is joined to the partial reflector, The second waveplate is joined to the partial reflector. The apparatus according to claim 3.

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

11. The apparatus according to claim 3, wherein the apparatus is part of a virtual reality headset.

12. A method for using a reflex optical system in a head-mounted display, wherein the method is A step of transmitting light from the display through a first reflective polarizer and a first lens, 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, The first thickness profile is measured between the first surface and the second surface of the first lens. Steps and A step of transmitting light from the first lens to a partial reflector through a first waveplate, The first waveplate is located between the partial reflector and the first lens. The first lens is located between the first waveplate and the first reflecting polarizer. Steps and The step of transmitting light from the partial reflector to the second lens through the second waveplate, 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 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. The second lens is positioned symmetrically with respect to the first lens such that the third surface is closer to the second surface than the first surface, and the second surface is closer to the third surface than the fourth surface. Steps and A step of transmitting light through the second lens to the second reflecting polarizer, wherein the second lens is located between the second waveplate and the second reflecting polarizer. Methods that include...

13. The method according to claim 12, wherein the first thickness profile corresponds to a plano-convex lens.

14. The first reflective polarizer is located on the first surface, The second reflecting polarizer is located on the fourth surface, The method according to claim 12.

15. The method according to claim 12, wherein the first waveplate and the second waveplate are quarter-waveplates.

16. The method according to claim 12, wherein the high-speed axis of the first waveplate and the high-speed axis of the second waveplate are oriented in the same direction.

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

18. The first waveplate is joined to the first lens, The second waveplate is joined to the second lens, The first waveplate is joined to the partial reflector, The second waveplate is joined to the partial reflector. The method according to claim 12.

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

20. The steps include: reflecting light to the partial reflector using the second reflective polarizer; The steps include: reflecting light from the partial reflector through the second lens and the second polarizer; The method according to claim 12, further comprising:

Images