Polarization multiplexing optical systems for head-mounted display systems

Abstract

The present disclosure generally relates to techniques for improving the performance and efficiency of display systems, such as laser scanning beam display systems, or other types of display systems (e.g., microdisplays) in HMD systems or other devices. The display systems of the present disclosure may utilize polarization multiplexing, which allows for improved optimization of diffractive optics. In at least some implementations, the display system selectively polarizes wavelength-dependent light (e.g., colors) or fields of view. The optical combiner may include polarization-sensitive diffractive optics elements that are optimized for a subset of colors or a portion of the entire field of view, respectively, thereby providing improved corrective optics for the display system.

Description

Technical Field

[0001] This disclosure generally relates to display systems, and more particularly to improving the efficiency and performance of display systems.

Background Art

[0002] One modern virtual reality ("VR") experience is generated using a head-mounted display ("HMD"), which can be tethered to a stationary computer (e.g., a personal computer ("PC"), laptop, or game console), combined with and / or integrated with a smartphone and / or its associated display, or made self-contained. Generally, an HMD is a display device worn on the user's head and has a small display device in front of one (monocular HMD) or each eye (binocular HMD). The display unit is typically miniaturized and can include, for example, CRT, LCD, liquid crystal on silicon (LCoS), OLED technology, or a laser scan beam display. A binocular HMD has the possibility of displaying different images for each eye. This ability is used to display stereoscopic images.

[0003] With the advancement of smartphones, high-resolution televisions, and other electronic devices, the demand for higher-performance displays has been increasing. The growing popularity of virtual reality and augmented reality systems, particularly those using HMDs, has further enhanced such demand. Virtual reality systems typically completely cover the wearer's eyes and use "virtual" reality instead of the actual or physical view (or actual reality) in front of the wearer, while augmented reality systems typically 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, and a mediated reality system can similarly present information to the viewer that combines elements of the real world with virtual elements.

[0004] For augmented reality applications, see-through optical couplers can be provided that combine virtual images and the real world and deliver them simultaneously to the user's eyes. Such technologies used in optical couplers utilize diffractive optics, which offer high efficiency, and among other advantages, they are easily fabricated. However, designing diffractive optical couplers that provide a high level of correction across the entire field of view and / or across multiple wavelengths can be a significant challenge. [Overview of the project]

[0005] In summary, a head-mounted display system may include a support structure and a display system connected to the support structure, the display system comprising a display light source and a selective polarizer optical system capable of receiving light from the display light source and outputting light of a first color in a first polarization state and light of a second color in a second polarization state. An optical system (optic) wherein the second polarization state includes a selective polarizer optical system orthogonal to the first polarization state, and an optical coupler arranged to receive light from the selective polarizer optical system and provide an image to the viewer's eye, wherein the optical coupler includes a first polarization-sensitive diffractive optical system element (PSDOE) comprising a first diffraction pattern that diffracts light in the first polarization state and allows light in the second polarization state to pass through without diffraction, the first PSDOE comprising a second diffraction pattern that diffracts light in the second polarization state and allows light in the first polarization state to pass through without diffraction, the second PSDOE comprising a second diffraction pattern that diffracts light in the second polarization state and allows light in the first polarization state to pass through without diffraction, the second PSDOE comprising a second diffraction pattern that provides a correction optimized for the second color. The selective polarizer optical system, the first PSDOE and the second PSDOE may each include a multi-twist retarder. At least one of the selective polarizer optical system, the first PSDOE and the second PSDOE may include a multi-twist retarder. The selective polarizer optical system, at least one of the first PSDOE and the second PSDOE, may include a liquid crystal material. The selective polarizer optical system may be operable to output light of a third color in the second polarization state, and the second diffraction pattern may provide optimized corrections for the second and third colors. The first color may be red, and the second and third colors may be green and blue, respectively. The optical coupler may include an in-coupler and an out-coupler. The support structure may include spectacle lenses. The display light source may include a laser scan beam system or a microdisplay.

[0006] In summary, a head-mounted display system may include a support structure and a display system connected to the support structure, the display system comprising a display light source and a selective polarizer optical system that receives light from the display light source having a full field of view and outputs light from a first field of view portion of the full field of view in a first polarization state and light from a second field of view portion of the full field of view in a second polarization state, wherein the second polarization state comprises a selective polarizer optical system orthogonal to the first polarization state and is arranged to receive light from the selective polarizer optical system and provide an image to the viewer's eyes. The HMD includes an optical coupler, the optical coupler being a first polarization-sensitive diffractive optical element (PSDOE) comprising a first diffraction pattern that diffracts light in a first polarization state and allows light in a second polarization state to pass through without diffraction, the first diffraction pattern providing an optimized correction for the first field of view portion, and a second PSDOE comprising a second diffraction pattern that diffracts light in a second polarization state and allows light in a first polarization state to pass through without diffraction, the second diffraction pattern providing an optimized correction for the second field of view portion. The first field of view portion may include an angular range from 0 degrees to M degrees, and the second field of view portion may have an angular range from M degrees to N degrees, where N is the angular range of the field of view of the HMD system and M is less than N. The first field of view portion and the second field of view portion may combine to form the entire field of view. The first field of view portion may be surrounded by the second field of view portion. The first field of view portion may include a first half of the entire field of view, and the second field of view portion may include a second half of the entire field of view. The first field of view portion and the second field of view portion may overlap each other at least partially. The selective polarizer optical system, each of the first PSDOE and the second PSDOE, may include a multi-twist retarder. The selective polarizer optical system, at least one of the first PSDOE and the second PSDOE, may include a multi-twist retarder. The selective polarizer optical system, at least one of the first PSDOE and the second PSDOE, may include a liquid crystal material. The optical coupler may include an in-coupler and an out-coupler. The support structure may include an spectacle lens.The display light source may include a laser scanning beam system or a microdisplay. [Brief explanation of the drawing]

[0007] In drawings, the same reference numerals identify similar elements or functions. The size and relative position of elements in a drawing are not necessarily drawn to scale. For example, the shapes and angles of various elements are not necessarily drawn to scale, and some of these elements may be arbitrarily enlarged and positioned to improve the readability of the drawing. Furthermore, the specific shapes of elements depicted may not necessarily convey any information about the actual shape of those elements, but may simply be chosen to make them easily recognizable in the drawing.

[0008] [Figure 1] This is a schematic diagram of a networked environment comprising one or more systems suitable for performing at least some of the technologies described in this disclosure.

[0009] [Figure 2] This figure shows an exemplary environment in which at least some of the technologies described are tethered to a video rendering computing system and used with an exemplary head-mounted display device that provides a virtual reality display to the user.

[0010] [Figure 3] This is a front view of an exemplary HMD device having a binocular display subsystem.

[0011] [Figure 4] The above shows a top view of a binocular display subsystem and an HMD device having various sensors according to an exemplary embodiment of the present disclosure.

[0012] [Figure 5]This is a schematic block diagram of a display system including a spatially variable polarizer, relating to one non-restrictively shown implementation.

[0013] [Figure 6] This is a schematic diagram of a scan beam display system relating to one non-restrictively shown implementation.

[0014] [Figure 7] This is a schematic diagram of a scan beam display system, including a spatially variable polarizer that is selectively adjusted based on a user-determined or inferred gaze position, relating to one non-restrictively shown implementation.

[0015] [Figure 8] This is a schematic diagram of a display system including a waveguide-based optical system and a spatially variable polarizer, relating to one non-restrictive implementation.

[0016] [Figure 9] This is a schematic diagram of a display system including a waveguide-based optical system that utilizes polarization multiplexing over wavelengths for one non-restrictive implementation.

[0017] [Figure 10] This is a schematic diagram of a display system including a waveguide-based optical system that utilizes polarization multiplexing across a field of view of one non-restrictively shown implementation.

[0018] [Figure 11A] This is a schematic diagram of the entire field of view of the HMD system, which consists of a first field of view surrounded by a second field of view. The optical coupler of the HMD system includes a first polarization-sensitive diffractive optical system element optimized for the first field of view and a second polarization-sensitive diffractive optical system element optimized for the second field of view.

[0019] [Figure 11B]It is a schematic diagram of the entire visual field of an HMD system composed of a first visual field portion arranged adjacent to a second visual field portion. The optical combiner of the HMD system includes a first polarization-sensitive diffractive optical element optimized for the first visual field portion and a second polarization-sensitive diffractive optical element optimized for the second visual field portion.

Embodiments for Carrying Out the Invention

[0020] In the following description, specific specific details are described in order to provide a complete understanding of various disclosed implementations. However, those skilled in the art will recognize that the implementation can be carried out without using one or more of these specific details, or by using other methods, components, materials, etc. In other examples, well-known structures associated with computer systems, server computers, and / or communication networks are not shown in detail or described in order to avoid unnecessarily obscuring the description of the implementation.

[0021] Unless the context requires otherwise, throughout this specification and the following claims, the word "comprising" is synonymous with "including" and is inclusive or open-ended (i.e., it does not exclude additional unrecited elements or method acts).

[0022] Throughout this specification, references to "one implementation" or "an implementation" mean that a particular feature, structure, or characteristic described in connection with that implementation is included in at least one implementation. Thus, when the phrases "in one implementation" or "in an implementation" appear in various places throughout this specification, they are not necessarily all referring to the same implementation. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more implementations.

[0023] When used in this specification and the appended claims, the singular form forms “a,” “an,” and “the” and includes plural referents, unless the context clearly indicates otherwise. It should also be noted that the term “or” is generally used in that sense and includes “and / or” unless the context clearly indicates otherwise.

[0024] The headings and abstracts of this disclosure provided herein are for convenience only and do not constitute any interpretation of the scope or meaning of the implementation.

[0025] This disclosure generally relates to techniques for improving the performance and efficiency of display systems, such as laser scan beam display systems, or other types of display systems (e.g., microdisplays). For many types of optical systems, such as diffractive optical systems used in augmented reality (AR) systems, providing correction across the entire field of view or across a wide range of wavelengths (e.g., red, green, blue) can be challenging. The display systems of this disclosure may utilize polarization multiplexing, which enables better optimization of the diffractive optical system. In at least some implementations, the display system may polarize light according to the wavelength of the field of view. The optical coupler may include a plurality of polarization-sensitive diffractive optical elements, each optimized for a subset of colors or a portion of the entire field of view, thereby providing an improved correction optical system for the display system.

[0026] First, exemplary uses of head-mounted display devices relating to the technology described herein are described with reference to Figures 1 to 4. Next, exemplary implementations of display systems incorporating the features of the present disclosure are described with reference to Figures 5 to 11. Exemplary head-mounted display systems and environments

[0027] Figure 1 is a schematic diagram of a networked environment 100 including a local media rendering (LMR) system 110 (e.g., a gaming system), and includes a local computing system 120 and a display device 180 (e.g., an HMD device having two display panels) suitable for performing at least some of the techniques described herein. In the embodiment depicted in Figure 1, the local computing system 120 is communicably connected to the display device 180 via a transmission link 115 (which may be wired or tethered via one or more cables (cable 220) as shown in Figure 2, for example, or wirelessly). In other embodiments, whether in addition to or instead of the HMD device 180, the local computing system 120 may provide encoded image data for display to a panel display device (e.g., a TV, console, monitor) via a wired or wireless link, each of which includes one or more addressable pixel arrays. In various embodiments, the local computing system 120 may include a general-purpose computing system, a gaming 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.

[0028] In the shown embodiments, the local computing system 120 has components including one or more hardware processors (e.g., a central processing unit or "CPU") 125, memory 130, various I / O ("input / output") hardware components 127 (e.g., a keyboard, mouse, one or more gaming 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, computer-readable storage 150 and network connectivity 160. Also in the shown embodiments, an embodiment of the eye-tracking subsystem 135 runs in memory 130 to perform at least some of the described techniques by performing automated operations that implement these described techniques, for example using the CPU 125 and / or GPU 144, and memory 130 may optionally further run one or more other programs 133 (e.g., to generate a video or other image to be displayed, such as a game program). As part of an automated operation implementing at least some of the techniques described herein, an eye-tracking subsystem 135 and / or program 133 running in memory 130 may store or retrieve various types of data, including an exemplary database data structure in storage 150, in this example the data used may include various types of image data information in database ("DB") 154, various types of application data in DB 152, various types of configuration data in DB 157, and additional information, such as system data or other information.

[0029] In addition to or in lieu of the image generation program 133, the LMR system 110 is also communicated via one or more computer networks 101 and network links 102 to an exemplary network-accessible media content provider 190 that may further provide content to the LMR system 110 for display in the embodiments depicted. For simplicity, some details about the network-accessible media content provider are not shown, but the media content provider 190 may include one or more computing systems (not shown) that may each 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.

[0030] While the display device 180 is shown as distinct from and separate from the local computing system 120 in the embodiment shown in Figure 1, it is understood that in certain 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, or an HMD device. In such embodiments, the transmission link 115 may include, for example, one or more system bus and / or video bus architectures.

[0031] As an example of operations performed locally by the local media rendering system 120, assume that the local computing system is a gaming computing system, and as a result, application data 152 includes one or more gaming applications executed via the CPU 125 using memory 130, and various video frame display data is generated and / or processed by an image generation program 133 together with the GPU 144 of the video subsystem 140, for example. To provide a high-quality gaming experience, a high volume 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 a wired or wireless transmission link 115.

[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 computing systems or devices interacting with each other and may be connected to other devices not shown, including, via one or more networks, e.g., via 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 the types of functions described, including desktop 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 goods, including appropriate communication capabilities. 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.

[0033] While various items are shown as being stored in memory or on storage while in use, it will also be understood that these items or parts thereof may be transferred between memory and other storage devices for memory management or data integrity purposes. Therefore, in some embodiments, for example, consisting of one or more software programs 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 techniques described may be executed by one or more processors or other configured hardware circuits or hardware including memory or storage. Some or all of the components, systems and data structures may be stored (e.g., as software instructions or structure 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 on portable media products read via a suitable drive (e.g., DVD discs, CD discs, optical discs, etc.) or a suitable connection. The system, components, and data structures may also be transmitted in some embodiments as generated data signals (e.g., as part of a carrier wave or other analog or digital propagation signal) over a variety of computer-readable transmission media, including wireless-based and wired / cable-based media, and may take various forms (e.g., as part of a single or multiplexed analog signal, or as multiple separate digital packets or frames). Such computer program products may take other forms in other embodiments. Therefore, the present invention can be implemented in conjunction with other computer system configurations.

[0034] Figure 2 shows an exemplary environment 200 in which at least some of the techniques described are used, along with an exemplary HMD device 202 connected to a video rendering computing system 204 via a tethered connection 220 (or, in other embodiments, a wireless connection) to provide a virtual reality display to a human user 206. The user wears the HMD device 202 and receives information to be displayed via the HMD device from the computing system 204 of a simulated environment that is different from the actual physical environment, and the computing system acts as an image rendering system that supplies images of the simulated environment, e.g., images generated by a game program and / or other software program running on the computing system, to the HMD device for display to the user. The user may have one or more I / O ("input / output") devices, in this example including handheld controllers 208 and 210, which further enable the user to move around a tracked volume 201 of the actual physical environment 200 and further enable the user to interact with the simulated environment.

[0035] In the illustrated example, the environment 200 may include one or more base stations 214 (two are shown, labeled base stations 214a and 214b) that can facilitate tracking of the HMD device 202 or controllers 208 and 210. As the user moves or changes the orientation of the HMD device 202, the HMD device's position is tracked, for example, to enable a corresponding portion of the simulated environment to be displayed to the user on the HMD device, and the controllers 208 and 210 may further use similar techniques to track the controllers' positions (optionally using that information to assist in determining or verifying the HMD device's position). 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.

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

[0037] In at least some implementations, the HMD device 202 may include one or more photodetectors or sensors that can be used to implement the tracking functions or other embodiments of the present disclosure. For example, a base station 214 may sweep 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, a single base station 214 is typically sufficient for 6-degree-of-freedom tracking, while in some embodiments, multiple base stations (e.g., base stations 214a, 214b) may be required or desired to provide stable room-scale tracking to the HMD device and its surroundings. In this example, the photodetectors are incorporated into the HMD device 202 and / or other tracked objects, e.g., controllers 208 and 210. In at least some implementations, to support low-latency sensor fusion, the photodetectors may be paired with accelerometers and gyroscope inertial measurement units ("IMUs") on each tracked device.

[0038] In at least some implementations, each base station 214 includes two rotors that sweep a linear beam across the tracked volume 201 on the vertical axis. At the start of each sweep cycle, the base station 214 may emit an omnidirectional light pulse (referred to as the “synchronization signal”) that is visible to all sensors on the tracked object. Thus, each sensor calculates its unique angular position on the swept volume by measuring the duration between the synchronization signal and the beam signal. Sensor distance and orientation can be resolved using multiple sensors fixed to a single rigid body.

[0039] One or more sensors located on the tracked object (e.g., HMD device 202, controllers 208 and 210) may have 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 stationary and time-varying signals (optical noise) with similar wavelengths to the base station signal 214, in at least some implementations, the base station light may be modulated in such a way that it is distinguishable from any interfering signals and / or facilitates filtering of the sensor from any wavelengths of radiation 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 the 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 position of the camera or other sensor used to determine the position of the HMD is located on the HMD or the object being tracked, whereas in outside-out tracking, the camera or sensor is located at a fixed position in the environment.

[0041] HMDs utilizing inside-out tracking use one or more cameras to "watch" and determine how their position changes relative to the environment. If the HMD moves, the sensors readjust their positions within the room, so that the virtual environment responds 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 are placed within a specific area. Along with "markerless" inside-out tracking, the HMD system uses prominent features that are naturally 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 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 front structure 343 supporting a front or forward camera 346 and one or more types of sensors 348a-348d (collectively 348). Some or all of the sensors 348, such as optical sensors that detect and use light information emitted from one or more external devices (not shown, e.g., base station 214 in Figure 2), may assist in determining the position and orientation of the device 344 in space. As shown, the forward 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., walls, ceilings, furniture, stairs, cars, trees, tracking markers, or any other type of object). A particular number of sensors 348 may be fewer or more than the number of sensors shown. The HMD device 344 may further include one or more additional components not mounted on the front 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 a magnetometer). As will be described in more detail below with respect to Figure 4, the HMD device may further include additional components (not shown) that are directed towards the user's eyes and optionally include one or more display panels and optical lens systems having one or more attached internal motors that change the alignment or other positioning of one or more optical lens systems and / or display panels within the HMD device.

[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 attached to one or more of the straps 345, and an autocorrect operation may include adjusting such straps using such motors to correct the alignment or other positioning of the HMD device on the user's head. The HMD device may include other support structures not shown herein (e.g., nosepiece, chin strap, etc.), whether in addition to or in place of the shown straps, and it will be understood that some embodiments may include motors attached to one or more such other support structures that 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 fixed to the user's head may be similarly attached to or part of one or more structures that affect the positioning of the display device, and in at least some embodiments, may include motors or other mechanical actuators to similarly 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.

[0044] Figure 4 shows a simplified top view 400 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 an optical lens system 410 and 412, each having one or more optical lenses. The display systems 402 and 404 may be mounted within or otherwise positioned within the housing (or frame) 414 and include a front section 416 (for example, identical or similar to the front surface 343 in Figure 3), a left temple 418, a right temple 420, and an inner surface 421 that contacts or is 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 a spectacle configuration that can be worn on the head 422 of the wearer, user 424, with the left temple 418 and the right temple 420 resting on the user's ears 426 and 428, respectively, while the nose assembly 492 may rest on the user's nose 430. A strap (not shown) or other structure may be used in some embodiments to secure the HMD device to the user's head, such as in the embodiments shown in Figures 2 and 3, but in the example of Figure 4, the HMD device 405 may be supported in part or in whole on the user's head by a nose display and / or right and left ear temples. The housing 414 is formed and may be sized to position each of two optical lens systems 410 and 412 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 the respective optical lens system and / or display panel.Although the housing 414 is shown in a simplified manner similar to eyeglasses for illustrative purposes, it should be understood that in practice, more elaborate structures (e.g., goggles, integrated headbands, helmets, straps, etc.) may be used to support and position the display systems 402 and 404 on the user's head 422.

[0045] The HMD device 405 in Figure 4 and other HMD devices described herein are capable of presenting a virtual reality display to a user via corresponding video presented at a display speed such as 30, 60, or 90 frames (or images) per second, while other embodiments of similar systems may present an augmented reality display to a user. Each of the displays 406 and 408 in Figure 4 may transmit to the eyes 432 and 434 of the user 424, respectively, through their respective optical lens systems 410 and 412, and generate focused light from their respective optical lens systems 410 and 412. The opening of the pupil 494 of each eye through which light passes typically has a pupil size ranging from approximately 2 mm in diameter in very bright conditions to about 8 mm in dim conditions, while the larger iris that encloses the pupil can be approximately 12 mm in size, and the pupil (and the iris surrounding it) can typically move a few more millimeters horizontally and / or vertically within the visible portion of the eye under the open eyelid, and this causes the pupil to move further to different depths from the optical lens of the display or other physical elements toward different horizontal and vertical positions as the eyeball rotates around its center (resulting in a three-dimensional volume from which the pupil can move). The light entering the user's pupil is viewed by the user 424 as an image and / or video. In some implementations, the distance between each of the optical lens systems 410 and 412 and the user's eyes 432 and 434 may be relatively short (e.g., less than 30 mm and less than 20 mm), which is advantageous because the weight of the optical lens systems and display system is relatively close to the user's face and can provide the user with a wider field of view, so that the HMD device feels lighter to the user. Although not shown herein, some embodiments of such HMD devices may include various additional internal and / or external sensors.

[0046] In the embodiments shown, the HMD device 405 in Figure 4 further includes hardware sensors and additional components, such as including one or more accelerometers and / or gyroscopes 490 (for example, as part of one or more IMU units). As described in more detail elsewhere in this specification, values ​​from the accelerometers and / or gyroscopes may be used to locally determine the orientation of the HMD device. Furthermore, the HMD device 405 may include one or more front cameras, such as a camera 485 located outside the front section 416, and the information therefrom may be used as part of the operation of the HMD device, for example, to provide AR functionality or positioning functionality. Furthermore, as described in more detail elsewhere in this specification, the HMD device 405 may further include other components 475 (e.g., electronic circuits that control the display of images on the display panels 406 and 408, internal storage, one or more batteries, a position tracking device that interacts with an external base station, etc.). Other embodiments may not include one or more of the components 475, 485 and / or 490. Although not shown here, some embodiments of such HMD devices may include a variety of additional internal and / or external sensors to track various other types of movement and position, such as the user's body, eyes, controllers, etc.

[0047] In the embodiments shown, the HMD device 405 of Figure 4 further includes hardware sensors and additional components that may be used by embodiments disclosed as part of the described techniques for determining the user's pupil or gaze direction, and may be provided as one or more components associated with the HMD device for such use as described elsewhere in this specification. For example, in this example, for use in obtaining information about the actual position of the user's pupils 494 separately for each pupil, the hardware sensors in this example include one or more eye-tracking assemblies 472 of eye-tracking subsystems 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.

[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, although only four eye-tracking assemblies 472 are shown in Figure 4 for clarity, it should be understood that in practice, different numbers of eye-tracking assemblies may be provided. In some embodiments, four eye-tracking assemblies are provided for each eye of the user 424, for a total of eight eye-tracking assemblies 472. Furthermore, in at least some implementations, 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 reaching the photodetector.

[0049] As will be described in more detail elsewhere in this specification, 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 at least some embodiments, the HMD device 405 may include one or more internal motors 438 (or other motion mechanisms) that can be used to move one or more alignments and / or other positionings (e.g., in the vertical, horizontal left-right, and / or horizontal front-back directions) of the optical lens systems 410 and 412 and / or display panels 406 and 408 located within the housing of the HMD device 405, for example, to personalize 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 controls 437 on the housing 414 and / or via user operation of one or more associated separate I / O controllers (not shown). In other embodiments, the HMD device 405 may control the alignment and / or other positioning of the optical lens systems 410 and 412 and / or the display panels 406 and 408 without using such a motor 438, by using an adjustable positioning mechanism (e.g., a screw, a slide, a ratchet, etc.) that is manually modified by the user, for example, through the use of a control 437. Furthermore, while Figure 4 shows a motor 438 for only one of the near-to-eye display systems, each near-to-eye display system may, in some embodiments, 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).

[0050] The techniques described may be used in some embodiments having a display system similar to that shown, while in other embodiments other types of display systems may be used, including the use of a single optical lens or the use of multiple such optical lenses and display devices. Non-exclusive examples of other such devices include cameras, telescopes, microscopes, binoculars, spot ranges, survey ranges, etc. Furthermore, as described elsewhere in this specification, the techniques described may be used with a wide variety of display panels or other display devices that emit light to form an image viewed by one or more users through one or more optical lenses. In other embodiments, the user may view one or more images through one or more optical lenses that are produced in a manner other than through a display panel, such as on a surface that reflects light from another light source (e.g., a laser scan beam), partially or entirely. Exemplary display system

[0051] Figure 5 is a schematic block diagram of a display system 500 relating to one non-exclusive implementation. The display system 500 may be a head-mounted display system, for example, the display system of the head-mounted display system described above, or any other type of display system (e.g., a wearable or non-wearable display system). The display system 500 may include a scan-beam display system, or another type of display system (e.g., a microdisplay). In at least some implementations, the display system 500 may be one of two substantially identical display systems provided in a device such as a head-mounted display device.

[0052] The display system 500 includes a display light source 502 optically connected to a pupil relay system 504. The display light source 502 may include a laser scan beam light source, a microdisplay, or any other suitable display light source. The pupil relay system 504 is arranged to relay the first pupil from the display light source 502 to a second pupil (or other image plane, surface, or material) of the viewer's eye 506. The pupil relay system 504 includes a polarization-sensitive optical system 508 (e.g., a post-scan optical system), which may include one or more waveguide-based optical systems, pancake optical systems, birdbath optical systems, coating-based optical systems, or other optical systems. The polarization-sensitive optical system 508 may include one or more components. The efficiency of the polarization-sensitive optical system 508 may be very sensitive to the polarization of the light passing through it. That is, different polarizations will significantly change the intensity and stray light escaping from the polarization-sensitive optical system 508.

[0053] To optimize the polarization of light supplied to the polarization-sensitive optical system 508, the pupil relay system 504 of the display system 500 further includes a spatially variable polarizer 510 having a spatially variable polarization depending on the position, which compensates for changes in polarization in order to provide the polarization-sensitive optical system 508 with uniformly polarized light, or more generally, optimized polarized light. For example, the polarization-sensitive optical system 508 may be configured to compensate for or "cancel out" any polarization generated from the combined angle by one or more mirrors or other optical systems. Furthermore, as described below, the spatially variable polarizer 510 may be selectively adjusted in real time based on the user's gaze position to provide optimized performance for a region or field of view.

[0054] The spatially variable polarizer 510 may include a wavelength retarder formed of a birefringent material. Birefringence is a property of materials having a refractive index that depends on the polarization and direction of light propagation. The wavelength retarder changes the polarization state or phase of light traveling through it. The wavelength retarder may have a slow axis (or anomalous axis) and a fast axis (normal axis). As polarized light travels through the wavelength retarder, light along the fast axis travels faster than light along the slow axis.

[0055] As described above, the spatially variable polarizer 510 can provide a phase difference that changes as a function of position, e.g., horizontal position, vertical position, and radial position, across a field of view (e.g., on-axis to off-axis) that enables a more uniform and efficient dispersion of light from the display light source 502 to the polarization-sensitive optical system 508. The specific way in which the delay of the spatially variable polarizer 510 changes may depend on the specific structure and materials of the optical system of the display system 500, such as the polarization state of the incident light, the angle of incidence, the material, and the shapes of various components.

[0056] For example, a spatially varying polarizer 510 may not provide a delay at a first position, but at a second position of the spatially varying polarizer, it may linearly increase the delay to provide a delay of λ / 4 (or other values). In general, a spatially varying polarizer 510 may provide a delay that varies in any way as a function of position, and the amount of the delay may be any value (e.g., λ / 20, λ / 10, λ / 4, λ, 2λ). Furthermore, the amount of the delay may increase in only one or more directions, decrease in only one or more directions, or increase and decrease in both directions. The amount of the delay may vary continuously or in many steps. The amount of the delay may vary according to any type of function, including, for example, a linear function, a polynomial function, an exponential function, a step function, other types of functions, or a combination thereof.

[0057] In at least some implementations, the spatially varying polarizer 510 may be formed in a multi-twist retarder (MTR), which is a waveplate-shaped phase difference film that provides precise and customized levels of broadband, narrowband, or multiband delay in a single thin film. More specifically, the MTR comprises two or more twisted liquid crystal (LC) layers on a single substrate, each having a single alignment layer. Subsequent LC layers are directly aligned by the previous layer, enabling simple manufacturing and automatic interlayer alignment, resulting in a monolithic film with a continuously varying optical axis.

[0058] Figure 6 is a schematic diagram of a scan beam display system or projector 600 relating to one non-limiting implementation. The scan beam display system 600 includes a light source 602, which may be a laser light source emitting a beam 604. The light source 602 may further include two light sources, for example, a red light source, a green light source and a blue light source. In such an example, the multiple light sources may be combined into a single beam by a beam combiner. In at least some implementations, the light source 602 may include one or more colored light sources (e.g., red, green, blue) and a light source emitting an invisible beam, for example, an infrared beam or an ultraviolet beam, which can be used for various purposes such as eye tracking.

[0059] The beam 604 is incident on a scanning platform 606, which may include a micro-electromechanical system (MEMS) based scanner, and is reflected by the platform's scanning mirror 608 to generate a controlled output beam 610. The scanning platform 606 may include a diffraction grating, a moving diffraction grating, an optical bulb, a rotating mirror, a movable silicon device, a digital optical projector device, a flying spot projector, a liquid crystal on silicon (LCoS) device, or other scanning or modulation device. The scanning platform 606 may be connected to one or more drive circuits selectively controlled by a controller 612 connected to the scanning platform and the light source 602, and one or more drive circuits may include any suitable control circuit having one or more components. The drive circuits adjust the direction in which the scanning mirror 608 deflects the incident beam 604, causing the output beam 610 to generate a scan, e.g., a raster scan, thereby generating an image to be displayed on an image surface such as a display surface or the viewer's eye 614.

[0060] Figure 7 is a schematic diagram of a scan beam display system or projector 700 relating to one non-restrictively shown implementation. The scan beam display system 700 may be similar in many respects to or identical to the scan beam display system 600 in Figure 6. Therefore, similar components are referred to by the same numbers, and for simplicity, a discussion of such components will not be repeated here.

[0061] The scan beam display system 700 includes a post-scan correction optics system 702 (post-scan optics) and a collimation optics system 704. The post-scan optics system 702 may include one or more optics located in the optical path after the scan platform 606 and may be generally referred to herein as “post-scan”. The post-scan correction optics system 702 may be designed and configured to correct or adjust one or more distortion artifacts in the projected image. Examples of such distortions may include smile distortion, pincushion distortion, barrel distortion, and off-axis projection-based distortion. It should be understood that these are merely non-limiting examples of types of distortion that the post-scan correction optics system 702 may correct.

[0062] The post-scan optical system 702 may include one or more waveguide-based optical systems, pancake optical systems, birdbath optical systems, coating-based optical systems, etc. The post-scan optical system may include one or more components. The efficiency of the post-scan optical system 702 may be very sensitive to the polarization of the light passing through it. That is, different polarizations will significantly change the intensity and the stray light escaping from the post-scan optical system 702. In at least some implementations, the display system 700 may include a collimating or beamforming optical system 704 that can be used to at least partially recover the loss of infinity focus caused by the post-scan optical system 702.

[0063] As described above, the display system 700 further includes a polarization compensation optical system in the form of a spatially variable polarizer 706 positioned between the scan mirror 608, which has very high polarization sensitivity and provides polarization compensation to the post-scan optical system 702, and the post-scan optical system 702. The spatially variable polarizer 706 may be positioned, for example, on, next to, or inside the post-scan optical system 702. In other implementations, the spatially variable polarizer 706 is positioned at other locations in the optical path between the light source 602 and the displayed image (e.g., pre-scan, post-scan, adjacent to the light source, etc.).

[0064] In at least some implementations, the controller 612 may be operably coupled to a spatially variable polarizer 706 that selectively changes the spatially dependent phase delay of the spatially variable polarizer to any desired configuration. In such implementations, one or more thin-film transistor layers may be provided that enable the spatially dependent phase delay of the spatially variable polarizer 706 to be selectively controlled by the controller 612. The controller 612 can control the phase difference at any desired rate, such as once, periodically, or at a rate equal to the frame rate of the display system 700 or a small part thereof.

[0065] In at least some implementations, the controller 612 may be operable to receive eye-tracking information 708, which may be used to selectively adjust the spatially dependent phase delay of a spatially varying polarizer 706 that is optimized in an optimized region where the user is likely to be fixated. Such eye-tracking information may be received from the eye-tracking subsystem, from information about the displayed content (e.g., the focus of an object), or from any other source that provides information about what the user is likely to be fixated on in the display.

[0066] As described above, the efficiency of the post-scan optics 702 can be highly sensitive to the polarization of the light passing through it. That is, different polarizations will significantly alter the intensity and the amount of stray light escaping from the post-scan optics 702. Optimizing the polarizer 706, which varies spatially over relatively small areas or fields of view (e.g., 0-10 degrees, 0-30 degrees, or other areas), may be advantageous and can provide a significantly better performance than optimizing over the entire field of view. Using eye-tracking information, the system may optimize areas with various characteristics (e.g., intensity, stray light) while configuring areas outside of lower-performance areas (e.g., lower brightness, more stray light). Because the user's vision is not good enough to distinguish peripheral areas, the user may not even be aware that the display performance is degraded outside the area they are fixated on.

[0067] Figure 8 is a schematic diagram of a display system 800 for use in a head-mounted display system relating to one non-limiting implementation, including a waveguide-based optical system and a polarization-compensating optical system in the form of a spatially varying polarizer. The display system 800 may include a lens or support structure 802 (e.g., prescription or non-prescription spectacle lenses). The waveguide structure 804 may be at least partially embedded within the structure 802 or positioned in close proximity to the structure (e.g., in front of or behind the structure). The waveguide 804 may be a rectangular (or other shaped) prism structure formed of a material having a refractive index sufficiently different from that of the surrounding structure (e.g., structure 802) to provide total internal reflection within the waveguide.

[0068] To enable light to couple into waveguide 804, the display system 800 includes an in-coupler 806 physically connected to a first portion of the waveguide. Similarly, to enable light to couple from waveguide 804 toward the viewer's eye 810, the display system 800 includes an out-coupler 808 physically connected to a second portion of the waveguide. As described above, the display light that in-couples through in-coupler 806 and out-couples through out-coupler 808 may originate from a display light source, such as a projector, a scanning laser projector, a microdisplay, or other display light source. In non-limiting examples, couplers 806 and 808 may include one or more of the following: diffraction gratings, holograms, holographic optical elements, volume diffraction gratings, surface relief diffraction gratings, etc. Couplers 806 and 808 may be reflective couplers or transmissive couplers. For example, structure 802 may include a right spectacle lens, in-coupler 806 may be positioned near the edge of the spectacle lens that is close to the display source (e.g., a projector), and out-coupler may be positioned toward the center of the spectacle lens so that the viewer can see the light from waveguide 804 while looking in a straight line or roughly straight ahead.

[0069] The display system 800 further includes a polarization-compensating optical system in the form of a spatially variable polarizer 812. In the non-limiting illustrated example, as described above, the spatially variable polarizer 812 is positioned adjacent to the in-coupler 806 to provide polarization compensation for light entering the waveguide 804, which can be highly polarization-sensitive. The spatially variable polarizer 812 may be positioned, for example, on the waveguide 804, adjacent to it, or inside it (as shown by the dashed line). In at least some implementations, the spatially variable polarizer 812 is positioned, for example, adjacent to either the in-coupler 806 side or the out-coupler 808 side. In other implementations, the spatially variable polarizer 812 is positioned elsewhere in the optical path between the display light source and the viewer's eye to provide polarization compensation.

[0070] Figure 9 is a schematic diagram of a display system 900 for an augmented reality system that utilizes polarization multiplexing to provide a waveguide structure optimized over wavelength (e.g., color). Display system 800 includes several components that are similar to or identical to the components of display system 800, and the components are identified by the same reference numeral. Display system 900 may include a lens or support structure 802 (e.g., prescription or non-prescription spectacle lenses). The optical coupler structure 902 may be at least partially embedded within structure 802 (e.g., the lens) or positioned in close proximity to the structure (e.g., in front of or behind the structure). The optical coupler 902 may be a rectangular (or other shaped) structure formed of a material having a refractive index sufficiently different from that of the surrounding structure (e.g., structure 802) to provide total internal reflection within at least a portion of the optical coupler.

[0071] To enable light to be coupled to the optical coupler 902, the display system 900 includes an in-coupler 806 that is physically connected to a first portion of the optical coupler 902. Similarly, to enable light to be coupled from the optical coupler 902 toward the viewer's eye 810, the display system 900 includes an out-coupler 808 that is physically connected to a second portion of the optical coupler opposite to the first portion. The display light that is in-coupled through the in-coupler 806 and out-coupled through the out-coupler 808 as described above may originate from the optical engine 908 and may include a display light source 910, such as a projector, a scanning laser projector, a microdisplay, or other display light source. In non-limiting examples, couplers 806 and 808 may include one or more of the following: diffraction gratings, holograms, holographic optical elements, volume diffraction gratings, surface relief diffraction gratings, etc. Couplers 806 and 808 may be reflective couplers or transmissive couplers. For example, structure 802 may include a right spectacle lens, in-coupler 806 may be positioned near the edge of the spectacle lens adjacent to the display source (e.g., a projector), and out-coupler may be positioned toward the center of the spectacle lens so that the viewer can see the light from the optical coupler 902 while looking straight ahead or roughly straight ahead. Furthermore, in at least some implementations, the components shown in Figure 9 may be for one eye of the user, and a similar or identical set of components may be provided for the other eye of the user to provide binocular display.

[0072] In the illustrated example, the optical engine 908 includes a selective polarizer optical system (SPO) 912 (e.g., a microdisplay, scan beam) located in front of the light source 910. The selective polarizer optical system 912 may be formed of a liquid crystal material, such as the multi-twist retarder (MTR) described above, and may be similar to or identical to the spatially variable polarizers described elsewhere in this specification. Generally, light from a display source exiting the selective polarizer optical system is collimated by a collimator 914 and then interacts with an in-coupler 806 guided by an optical coupler 902. The optical coupler 902 provides optical correction and transmits the light to the out-coupler 808, and the light 920 exits the optical coupler 902 and presents an image to the user's eye 810.

[0073] More specifically, the selective polarizer optical system 912 receives light 916 containing multiple wavelengths or colors C1, C2, C3 (e.g., red, green, blue). The selective polarizer optical system 912 is operable to receive light 916 from the display light source 910 and output light 918 of a first color (C1) in a first polarization state (P1), and light of at least a second color (C2 or C3) in a second polarization state (P2), where the second polarization state is orthogonal to the first polarization state. As a non-limiting example, the selective polarizer optical system 912 may convert red light (C1) into P polarization states (P1), and green (C2) and blue (C3) light into polarization states (P2).

[0074] The optical coupler 902 includes a first polarization-sensitive diffractive optical element (PSDOE) 904 and a second polarization-sensitive diffractive optical element 906. Each of the first and second polarization-sensitive diffractive optical elements may be formed from a liquid crystal material, for example, a multi-twist retarder, and may be similar to or identical to a spatially varying polarizer as described elsewhere in this specification. The first polarization-sensitive diffractive optical element 904 includes a first diffraction pattern that diffracts light in a first polarization state (P1) and allows light in a second polarization state (P2) to pass through without diffraction. Similarly, the second polarization-sensitive diffractive optical element 906 includes a second diffraction pattern that diffracts light in a second polarization state (P2) and allows light in a first polarization state (P1) to pass through without diffraction. The first diffraction pattern is designed to provide an optimized correction for a first color (C1), and the second diffraction pattern is designed to provide an optimized correction for at least a second color (e.g., C2 and / or C3).

[0075] As described above, designing a diffractive optical system element that provides appropriate correction across the entire desired wavelength range (e.g., 380 to 740 nanometers) can be challenging. By polarizing the light from the light source 910 according to color, each of the first and second polarization-sensitive diffractive optical systems 904 and 906 can be optimized for a narrower range of wavelengths, and the entire optical coupler 902 allows for more design freedom and ultimately better correction. Continuing the above example, since the first polarization-sensitive diffractive optical system element does not perceive green or blue light in the second polarization state (P2), the first polarization-sensitive diffractive optical system element 904 can be optimized only for red light (C1) in the first polarization state (P1). Similarly, since the second polarization-sensitive diffractive optical system element does not perceive red light (C1) in the first polarization state (P1), the second polarization-sensitive diffractive optical system element 906 can be optimized only for green light (C2) and blue light (C3) in the second polarization state (P2).

[0076] Figure 10 is a schematic diagram of a display system 1000 for an augmented reality system that utilizes polarization multiplexing to provide a waveguide structure optimized over the entire or overall field of view of the display system. The display system 1000 includes several components that are similar to or identical to the components of the display system described above, and the components are identified by the same reference numerals. The display system 1000 may include a lens or support structure 802 (e.g., prescription or non-prescription spectacle lenses). The optical coupler structure 1002 may be at least partially embedded within the structure 802 (e.g., the lens) or positioned in close proximity to the structure (e.g., in front of or behind the structure). The optical coupler 1002 may be a rectangular (or other shaped) structure formed of a material having a refractive index sufficiently different from that of the surrounding structure (e.g., structure 802) to provide total internal reflection within at least a portion of the optical coupler.

[0077] To enable light to be coupled to the optical coupler 1002, the display system 1000 includes an in-coupler 806 that is physically connected to a first portion of the optical coupler 1002. Similarly, to enable light to be coupled from the optical coupler 1002 to the viewer's eye 810, the display system 1000 includes an out-coupler 808 that is physically connected to a second portion of the optical coupler opposite to the first portion. As described above, the display light that is in-coupled through the in-coupler 806 and out-coupled through the out-coupler 808 may originate from the optical engine 1008 and may include a display light source 1010, such as a projector, a scanning laser projector, a microdisplay, or other display light source. In non-limiting examples, couplers 806 and 808 may include one or more of the following: diffraction gratings, holograms, holographic optical elements, volume diffraction gratings, surface relief diffraction gratings, etc. Couplers 806 and 808 may be reflective couplers or transmissive couplers. For example, structure 802 may include a right spectacle lens, the in-coupler 806 may be positioned near the edge of the spectacle lens that is close to the display source (e.g., a projector), and the out-coupler may be positioned toward the center of the spectacle lens so that the viewer can see the light from the optical coupler 1002 while looking straight ahead or roughly straight ahead. Furthermore, in at least some implementations, the components shown in Figure 10 may be for one eye of the user, and a similar or identical set of components may be provided for the other eye of the user to provide binocular display.

[0078] In the illustrated example, the optical engine 1008 includes a selective polarizer optical system (SPO) 1012 (e.g., a microdisplay, scan beam) located in front of the light source 1010. The selective polarizer optical system 1012 may be formed of a liquid crystal material, for example, a multi-twist retarder (MTR). Generally, light from a display source exiting the selective polarizer optical system 1012 is collimated by a collimator 1014 and then interacts with an in-coupler 806 guided by an optical coupler 1002. The optical coupler 1002 provides optical correction and transmits the light to the out-coupler 808, and the light 1020 exits the optical coupler 1002 and presents an image to the user's eye 810.

[0079] More specifically, the selective polarizer optical system 1012 receives light 1016 containing multiple wavelengths or colors C1, C2, C3 (e.g., red, green, blue) through the entire or whole field of view provided to the user's eye 810. The selective polarizer optical system 1012 is operable to receive light 1016 from the display light source 1010 and output light 1018 in a first field of view (FOV1) in a first polarization state (P1) and light 1019 in a second field of view (FOV2) in a second polarization state (P2), the second polarization state being orthogonal to the first polarization state. As a non-limiting example, the selective polarizer optical system 1012 may convert light that is on the axis and within a narrow angular range (e.g., within 20 degrees from the axis) into P polarization states (P1), and light that is in the entire field of view outside the narrow angular range into polarization states (P2). Figure 11A shows an exemplary full field of view 1100 of an HMD system, comprising a first field of view portion 1102 having a narrow angular range surrounded by a second field of view portion 1104. Figure 11B shows another example of the full field of view 1100, comprising a first field of view portion 1106 positioned adjacent to the second field of view portion 1108. The embodiments shown are provided for illustrative purposes only, and it should be understood that other configurations of the first and second field of view portions may be used.

[0080] The optical coupler 1002 includes a first polarization-sensitive diffractive optical element (PSDOE) 1004 and a second polarization-sensitive diffractive optical element 1006. Each of the first and second polarization-sensitive diffractive optical elements may be formed from a liquid crystal material, for example, a multi-twist retarder. The first polarization-sensitive diffractive optical element 1004 includes a first diffraction pattern that diffracts light in a first polarization state (P1) and allows light in a second polarization state (P2) to pass through without diffraction. Similarly, the second polarization-sensitive diffractive optical element 1009 includes a second diffraction pattern that diffracts light in a second polarization state (P2) and allows light in a first polarization state (P1) to pass through without diffraction. The first diffraction pattern is designed to provide an optimized correction for a first field of view (FOV1), and the second diffraction pattern is designed to provide an optimized correction for a second field of view (FOV2).

[0081] As described above, designing diffractive optical elements that provide appropriate correction across the entire field of view of a display system can be challenging. By polarizing the light from the light source 1010 according to the portion of the field of view of the entire field of view, each of the first and second polarization-sensitive diffractive optical elements 1004 and 1006 can be optimized for a smaller field of view, and the entire optical coupler 1002 allows for more design freedom and ultimately better correction. Continuing the above example, since the first polarization-sensitive diffractive optical element does not perceive light in the wide field of view (FOV2) in the second polarization state (P2), the first polarization-sensitive diffractive optical element 1004 can be optimized only for the narrow field of view (FOV1) in the first polarization state (P1). Similarly, since the second polarization-sensitive diffractive optical element does not perceive light in the narrow field of view (FOV1) in the first polarization state (P1), the second polarization-sensitive diffractive optical element 1006 can be optimized only for light in the wide field of view (FOV2) in the second polarization state (P2).

[0082] In at least some implementations, a controller (e.g., controller 612) can be operably coupled to selective polarizer optical systems and / or polarization-sensitive diffractive optical system elements to selectively vary their space-dependent phase delays to any desired configuration. In such implementations, one or more thin-film transistor layers may be provided that enable selective control of the space-dependent phase delays of the components. The controller can control the phase difference at any desired rate, such as, for example, once, periodically, or at a rate equal to the frame rate of the display system or a small part thereof.

[0083] By utilizing the spatially variable polarizers described herein, optical system designers have a great deal of freedom to produce optical systems with improved performance and efficiency, enabling display systems to provide a better viewing experience, reduce costs, make them smaller or heavier, consume less power, and offer other advantages that will be apparent to those skilled in the art.

[0084] The various implementations described above can be combined to provide further implementation forms. Based on the detailed descriptions above, these and other modifications may be made to the implementations. In general, the terms used in the following claims should not be construed to limit the claims to any specific implementation disclosed herein and in the claims, but rather to include all possible implementations together with the entire scope of equivalents covered by such claims. Accordingly, the claims are not limited by this disclosure.

Claims

1. Support structure and, The display system connected to the aforementioned support structure and The display system is equipped with, Display light source and A selective polarizer optical system capable of receiving light from the display light source and outputting light of a first color in a first polarization state, light of a second color in a second polarization state, and light of a third color in the second polarization state, wherein the second polarization state is a selective polarizer optical system orthogonal to the first polarization state, An optical coupler is arranged to receive light from the aforementioned selective polarizer optical system and provide an image to the viewer's eye. It has, The aforementioned optical coupler is, A first polarization-sensitive diffractive optical system (PSDOE) includes a first diffraction pattern that diffracts light in a first polarization state and allows light in a second polarization state to pass through without diffraction, wherein the first diffraction pattern provides optical correction for light of a first color, and the first PSDOE A second PSDOE comprising a second diffraction pattern that diffracts the light in the second polarization state and allows the light in the first polarization state to pass through without diffraction, wherein the second diffraction pattern provides optical correction for the light of the second color and the light of the third color. A head-mounted display system, including a head-mounted display system.

2. The head-mounted display system according to claim 1, wherein each of the selective polarizer optical system, the first PSDOE and the second PSDOE each has a multi-twist retarder.

3. The head-mounted display system according to claim 1 or 2, wherein the selective polarizer optical system, at least one of the first PSDOE and the second PSDOE, has a multi-twist retarder.

4. The head-mounted display system according to any one of claims 1 to 3, wherein the selective polarizer optical system, at least one of the first PSDOE and the second PSDOE, is made of a liquid crystal material.

5. The head-mounted display system according to any one of claims 1 to 4, wherein the first color is red, and the second and third colors are green and blue, respectively.

6. The head-mounted display system according to any one of claims 1 to 5, wherein the first color is red, and the second color is green or blue.

7. The head-mounted display system according to any one of claims 1 to 6, wherein the optical coupler has an in-coupler and an out-coupler.

8. The head-mounted display system according to any one of claims 1 to 7, wherein the support structure has eyeglass lenses.

9. The head-mounted display system according to any one of claims 1 to 8, wherein the display light source has a laser scan beam system or a microdisplay.

10. The head-mounted display system according to any one of claims 1 to 9, wherein the optical correction includes distortion correction.

11. Support structure and, The display system connected to the aforementioned support structure and The display system is equipped with, Display light source and A selective polarizer optical system capable of receiving light from a display light source having a full field of view and outputting light from a first field of view portion of the full field of view in a first polarization state and light from a second field of view portion of the full field of view in a second polarization state, wherein the second polarization state comprises a selective polarizer optical system orthogonal to the first polarization state, An optical coupler is arranged to receive light from the aforementioned selective polarizer optical system and provide an image to the viewer's eye. The optical coupler has, A first polarization-sensitive diffractive optical system element (PSDOE) includes a first diffraction pattern that diffracts light in a first polarization state and allows light in a second polarization state to pass through without diffraction, wherein the first diffraction pattern provides optical correction to the light in the first field of view portion, A second PSDOE comprising a second diffraction pattern that diffracts the light in the second polarization state and allows the light in the first polarization state to pass through without diffraction, wherein the second diffraction pattern provides optical correction to the light in the second field of view portion. Includes, The first field of view is surrounded by the second field of view. Head-mounted display system.

12. The head-mounted display system according to claim 11, wherein the first field of view portion has an angular range from 0 degrees to M degrees, and the second field of view portion has an angular range from M degrees to N degrees, where N is the angular range of the field of view of the head-mounted display system, and M is smaller than N.

13. The head-mounted display system according to claim 11 or 12, wherein the first field of view portion and the second field of view portion are combined to form the entire field of view.

14. The head-mounted display system according to any one of claims 11 to 13, wherein the first field of view portion has a first half of the entire field of view, and the second field of view portion has a second half of the entire field of view.

15. The head-mounted display system according to any one of claims 11 to 13, wherein the first field of view portion and the second field of view portion overlap each other at least partially.

16. The head-mounted display system according to any one of claims 11 to 15, wherein each of the selective polarizer optical system, the first PSDOE and the second PSDOE each has a multi-twist retarder.

17. The head-mounted display system according to any one of claims 11 to 15, wherein the selective polarizer optical system, at least one of the first PSDOE and the second PSDOE, has a multi-twist retarder.

18. The head-mounted display system according to any one of claims 11 to 17, wherein the selective polarizer optical system, at least one of the first PSDOE and the second PSDOE, is made of a liquid crystal material.

19. The head-mounted display system according to any one of claims 11 to 18, wherein the optical coupler has an in-coupler and an out-coupler.

20. The head-mounted display system according to any one of claims 11 to 19, wherein the support structure has eyeglass lenses.

21. The head-mounted display system according to any one of claims 11 to 20, wherein the display light source has a laser scan beam system or a microdisplay.

22. The head-mounted display system according to any one of claims 11 to 21, wherein the optical correction includes distortion correction.

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