PATENT DOCUMENT

Publication Number: US-11852819-B2
Application Number: US-202117479322-A
Country: US
Kind Code: B2

Title: Optical systems having multiple light paths for performing foveation

Abstract:
An electronic device may include a display module that produces foveated images having high and low resolution regions. The module may include a reflective display panel that produces first reflected light during first time periods and second reflected light during second time periods. The first reflected light may reflect off of a beam splitter to form the low resolution region of the foveated image. The second reflected light may be transmitted by the beam splitter, de-magnified by a lens, and redirected by an optical steering element to produce the high resolution region at a desired, adjustable, location in the foveated image. The reflective display panel may be replaced by sets of emissive display panels that concurrently display the high and low resolution regions in the foveated image. The sets of emissive display panels may be replaced by front-lit reflective display panels.

Claims:
What is claimed is: 
     
       1. A display system configured to display a foveated image having a first region with a first resolution and a second region with a second resolution greater than the first resolution, the display system comprising:
 an optical system configured to direct the foveated image; 
 a light source that produces illumination light; 
 a reflective display panel, wherein:
 during a first time period, the reflective display panel is configured to reflect the illumination light as first reflected light, and 
 during a second time period different from the first time period, the reflective display panel is configured to reflect the illumination light as second reflected light; 
 
 a polarizing beam splitter, wherein:
 the polarizing beam splitter is configured to reflect the first reflected light towards the optical system as the first region of the foveated image, and 
 the polarizing beam splitter is configured to transmit the second reflected light; 
 
 a lens configured to receive the second reflected light transmitted by the polarizing beam splitter and configured to de-magnify the second reflected light transmitted by the polarizing beam splitter to produce de-magnified light; and 
 an optical steering element configured to re-direct the de-magnified light through the polarizing beam splitter and towards the optical system as the second region of the foveated image. 
 
     
     
       2. The display system of  claim 1 , further comprising:
 control circuitry, wherein the control circuitry is configured to adjust the optical steering element to change a location of the second region in the foveated image. 
 
     
     
       3. The display system of  claim 2 , wherein the optical steering element comprises an adjustable mirror. 
     
     
       4. The display system of  claim 2 , further comprising:
 a mirror, wherein the optical steering element is configured to re-direct the de-magnified light towards the mirror and wherein the mirror is configured to reflect the de-magnified light through the polarizing beam splitter and towards the optical system as the second region of the foveated image. 
 
     
     
       5. The display system of  claim 4 , wherein the optical steering element comprises a switchable liquid crystal steering device. 
     
     
       6. The display system of  claim 4 , further comprising an additional lens, wherein the lens is optically interposed between the mirror and the polarizing beam splitter. 
     
     
       7. The display system of  claim 6 , further comprising a polarizing element, wherein the polarizing element is optically interposed between the additional lens and the polarizing beam splitter. 
     
     
       8. The display system of  claim 7 , wherein the polarizing element is configured to provide the de-magnified light with a polarization that is transmitted by the polarizing beam splitter. 
     
     
       9. The display system of  claim 2 , further comprising:
 a gaze tracking sensor, wherein the gaze tracking sensor is configured to gather gaze tracking data that identifies a gaze direction, and wherein the control circuitry is configured to adjust the optical steering element to align the location of the second region with the gaze direction identified by the gaze tracking data. 
 
     
     
       10. The display system of  claim 1 , wherein the reflective display panel comprises a liquid crystal on silicon (LCOS) display panel. 
     
     
       11. The display system of  claim 1 , wherein the reflective display panel comprises a digital-micromirror device display panel. 
     
     
       12. The display system of  claim 1 , further comprising:
 a mirror, wherein the mirror is configured to reflect the illumination light towards the polarizing beam splitter and wherein the mirror is configured to reflect the second reflected light transmitted by the polarizing beam splitter towards the lens; and 
 a partial mirror, wherein the partial mirror is configured to transmit the illumination light, wherein the partial mirror is configured to receive the second reflected light from the mirror, and wherein the partial mirror is configured to reflect the second reflected light towards the lens. 
 
     
     
       13. The display system of  claim 12 , wherein the lens is optically interposed between the partial mirror and the optical steering element, wherein the mirror is optically interposed between the partial mirror and the polarizing beam splitter, and wherein the polarizing beam splitter is optically interposed between the mirror and the reflective display panel. 
     
     
       14. The display system of  claim 1 , wherein the optical system comprises a waveguide having an input coupler configured to couple the foveated image into the waveguide and an output coupler configured to couple the foveated image out of the waveguide. 
     
     
       15. The display system of  claim 1 , wherein the first reflected light does not pass through the lens and is not redirected by the optical steering element. 
     
     
       16. The display system of  claim 1 , further comprising:
 a waveguide configured to propagate the first reflected light via total internal reflection and configured to propagate the de-magnified light via total internal reflection. 
 
     
     
       17. The display system of  claim 16 , wherein the waveguide comprises surface relief gratings. 
     
     
       18. The display system of  claim 1 , wherein the optical steering element has a first state in which the de-magnified light is re-directed in a first direction and in which the second region is at a first location in the foveated image, and wherein the optical steering element has a second state in which the de-magnified light is re-directed in a second direction different from the first direction and in which the second region is at a second location in the foveated image that is different from the first location. 
     
     
       19. The display system of  claim 18 , further comprising control circuitry configured to control the optical steering element to switch between the first and second states. 
     
     
       20. The display system of  claim 1 , further comprising a prism, wherein the prism is optically interposed between the light source and the reflective display panel.

Description:
This application is a continuation of international patent application No. PCT/US2020/060563, filed Nov. 13, 2020, which claims the benefit of U.S. provisional patent application No. 62/939,214, filed Nov. 22, 2019, which are hereby incorporated by reference herein in their entireties. 
    
    
     BACKGROUND 
     This relates generally to optical systems and, more particularly, to optical systems for displays. 
     Electronic devices may include displays that present images close to a user&#39;s eyes. For example, devices such as virtual reality and augmented reality headsets may include displays with optical elements that allow users to view the displays. 
     It can be challenging to design devices such as these. If care is not taken, the components used in displaying content may be unsightly and bulky and may not exhibit desired levels of optical performance. 
     SUMMARY 
     An electronic device such as a head-mounted device may have one or more near-eye displays that produce images for a user. The head-mounted device may be a pair of virtual reality glasses or may be an augmented reality headset that allows a viewer to view both computer-generated images and real-world objects in the viewer&#39;s surrounding environment. 
     The near-eye display may include a display module that generates light and an optical system that redirects the light from the display module towards an eye box. The optical system may include a waveguide having an input coupler and an output coupler. The light provided to the eye box may include a foveated image having a high resolution region and a low resolution region. The display module may generate the foveated image and may adjust the location of the high resolution region over time (e.g., so that the high resolution region overlaps the center of the viewer&#39;s gaze as the viewer&#39;s gaze changes). 
     The display module may include a light source that produces illumination light, a reflective display panel such as a liquid crystal on silicon (LCOS) or digital micromirror device (DMD) panel, a polarizing beam splitter, a lens, and an optical steering element such as an adjustable mirror or a switchable liquid crystal steering device. The reflective display panel may reflect the illumination light as first reflected light during a first time period and may reflect the illumination light as second reflected light during a second time period. The beam splitter may reflect the first reflected light towards the optical system as the low resolution region of the foveated image but may transmit the second reflected light. The lens may de-magnify the second reflected light transmitted by the polarizing beam splitter to produce de-magnified light. The optical steering element may re-direct the de-magnified light through the beam splitter and towards the optical system as the high resolution region of the foveated image. Control circuitry may adjust the optical steering element to change the location of the high resolution region in the foveated image over time. 
     In another suitable arrangement, the optical system may include first and second sets of emissive display panels such as micro light-emitting-diode (uLED) display panels, micro organic light-emitting diode (uOLED) display panels, and vertical-cavity surface-emitting laser (VCSEL) array display panels. The first set of emissive display panels may produce first illumination light. The beam splitter may reflect the first illumination light towards the optical system as the low resolution region of the foveated image. The second set of emissive display panels may produce second illumination light. The lens may de-magnify the second illumination light to produce de-magnified light. The optical steering element may re-direct the de-magnified light towards the beam splitter. The beam splitter may transmit the de-magnified light re-directed by the optical steering element towards the optical system as the high resolution region of the foveated image. Control circuitry may adjust the optical steering element to change the location of the high resolution region in the foveated image over time. If desired, the first and second sets of emissive display panels may be replaced with front-lit LCOS display panels. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a diagram of an illustrative system having a display in accordance with some embodiments. 
         FIG.  2    is a top view of an illustrative optical system having a display module with multiple optical paths for performing dynamic foveation operations in accordance with some embodiments. 
         FIG.  3    is a diagram of an illustrative foveated image having an adjustable high resolution region that may be output by an optical system of the type shown in  FIG.  2    in accordance with some embodiments. 
         FIG.  4    is a diagram an illustrative display module having reflective display panels for producing foveated images having an adjustable high-resolution region in accordance with some embodiments. 
         FIG.  5    is a diagram of an illustrative display module having emissive display panels for producing foveated images having an adjustable high-resolution region in accordance with some embodiments. 
         FIG.  6    is a diagram of an illustrative front-illuminated reflective display panel that may be used in a display module of the type shown in  FIG.  5    in accordance with some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     An illustrative system having a device with one or more near-eye display systems is shown in  FIG.  1   . System  10  may be a head-mounted device having one or more displays such as near-eye displays  14  mounted within support structure (housing)  20 . Support structure  20  may have the shape of a pair of eyeglasses (e.g., supporting frames), may form a housing having a helmet shape, or may have other configurations to help in mounting and securing the components of near-eye displays  14  on the head or near the eye of a user. Near-eye displays  14  may include one or more display modules such as display modules  14 A and one or more optical systems such as optical systems  14 B. Display modules  14 A may be mounted in a support structure such as support structure  20 . Each display module  14 A may emit light  22  (image light) that is redirected towards a user&#39;s eyes at eye box  24  using an associated one of optical systems  14 B. 
     The operation of system  10  may be controlled using control circuitry  16 . Control circuitry  16  may include storage and processing circuitry for controlling the operation of system  10 . Circuitry  16  may include storage such as hard disk drive storage, nonvolatile memory (e.g., electrically-programmable-read-only memory configured to form a solid state drive), volatile memory (e.g., static or dynamic random-access-memory), etc. Processing circuitry in control circuitry  16  may be based on one or more microprocessors, microcontrollers, digital signal processors, baseband processors, power management units, audio chips, graphics processing units, application specific integrated circuits, and other integrated circuits. Software code (instructions) may be stored on storage in circuitry  16  and run on processing circuitry in circuitry  16  to implement operations for system  10  (e.g., data gathering operations, operations involving the adjustment of components using control signals, image rendering operations to produce image content to be displayed for a user, etc.). 
     System  10  may include input-output circuitry such as input-output devices  12 . Input-output devices  12  may be used to allow data to be received by system  10  from external equipment (e.g., a tethered computer, a portable device such as a handheld device or laptop computer, or other electrical equipment) and to allow a user to provide head-mounted device  10  with user input. Input-output devices  12  may also be used to gather information on the environment in which system  10  (e.g., head-mounted device  10 ) is operating. Output components in devices  12  may allow system  10  to provide a user with output and may be used to communicate with external electrical equipment. Input-output devices  12  may include sensors and other components  18  (e.g., image sensors for gathering images of real-world object that are digitally merged with virtual objects on a display in system  10 , accelerometers, depth sensors, light sensors, haptic output devices, speakers, batteries, wireless communications circuits for communicating between system  10  and external electronic equipment, etc.). In one suitable arrangement that is sometimes described herein as an example, components  18  may include gaze tracking sensors that gather gaze image data from a user&#39;s eye at eye box  24  to track the direction of the user&#39;s gaze in real time. As an example, the gaze tracking sensors may include infrared or other light emitters that emit infrared light or other light towards the eye box and image sensors that sense the infrared or other light reflected off of the user&#39;s eye (e.g., where the sensed light identifies the gaze direction of the user&#39;s eye). 
     Display modules  14 A may include reflective displays (e.g., liquid crystal on silicon (LCOS) displays, digital-micromirror device (DMD) displays, or other spatial light modulators), emissive displays (e.g., micro-light-emitting diode (uLED) displays, organic light-emitting diode (OLED) displays, laser-based displays, etc.), or displays of other types. Light sources in display modules  14 A may include uLEDs, OLEDs, LEDs, lasers, combinations of these, or any other desired light-emitting components. 
     Optical systems  14 B may form lenses that allow a viewer (see, e.g., a viewer&#39;s eyes at eye box  24 ) to view images on display(s)  14 . There may be two optical systems  14 B (e.g., for forming left and right lenses) associated with respective left and right eyes of the user. A single display  14  may produce images for both eyes or a pair of displays  14  may be used to display images. In configurations with multiple displays (e.g., left and right eye displays), the focal length and positions of the lenses formed by components in optical system  14 B may be selected so that any gap present between the displays will not be visible to a user (e.g., so that the images of the left and right displays overlap or merge seamlessly). 
     If desired, optical system  14 B may contain components (e.g., an optical combiner, etc.) to allow real-world image light from real-world images or objects  25  to be combined optically with virtual (computer-generated) images such as virtual images in image light  22 . In this type of system, which is sometimes referred to as an augmented reality system, a user of system  10  may view both real-world content and computer-generated content that is overlaid on top of the real-world content. Camera-based augmented reality systems may also be used in device  10  (e.g., in an arrangement which a camera captures real-world images of object  25  and this content is digitally merged with virtual content at optical system  14 B). 
     System  10  may, if desired, include wireless circuitry and/or other circuitry to support communications with a computer or other external equipment (e.g., a computer that supplies display  14  with image content). During operation, control circuitry  16  may supply image content to display  14 . The content may be remotely received (e.g., from a computer or other content source coupled to system  10 ) and/or may be generated by control circuitry  16  (e.g., text, other computer-generated content, etc.). The content that is supplied to display  14  by control circuitry  16  may be viewed by a viewer at eye box  24 . 
       FIG.  2    is a top view of an illustrative display  14  that may be used in system  10  of  FIG.  1   . As shown in  FIG.  2   , near-eye display  14  may include one or more display modules such as display module  14 A and an optical system such as optical system  14 B. Optical system  14 B may include optical elements such as one or more waveguides  26 . Waveguide  26  may include one or more stacked substrates (e.g., stacked planar and/or curved layers sometimes referred to herein as waveguide substrates) of optically transparent material such as plastic, polymer, glass, etc. 
     If desired, waveguide  26  may also include one or more layers of holographic recording media (sometimes referred to herein as holographic media, grating media, or diffraction grating media) on which one or more diffractive gratings are recorded (e.g., holographic phase gratings, sometimes referred to herein as holograms). A holographic recording may be stored as an optical interference pattern (e.g., alternating regions of different indices of refraction) within a photosensitive optical material such as the holographic media. The optical interference pattern may create a holographic phase grating that, when illuminated with a given light source, diffracts light to create a three-dimensional reconstruction of the holographic recording. The holographic phase grating may be a non-switchable diffractive grating that is encoded with a permanent interference pattern or may be a switchable diffractive grating in which the diffracted light can be modulated by controlling an electric field applied to the holographic recording medium. Multiple holographic phase gratings (holograms) may be recorded within (e.g., superimposed within) the same volume of holographic medium if desired. The holographic phase gratings may be, for example, volume holograms or thin-film holograms in the grating medium. The grating media may include photopolymers, gelatin such as dichromated gelatin, silver halides, holographic polymer dispersed liquid crystal, or other suitable holographic media. 
     Diffractive gratings on waveguide  26  may include holographic phase gratings such as volume holograms or thin-film holograms, meta-gratings, or any other desired diffractive grating structures. The diffractive gratings on waveguide  26  may also include surface relief gratings formed on one or more surfaces of the substrates in waveguides  26 , gratings formed from patterns of metal structures, etc. The diffractive gratings may, for example, include multiple multiplexed gratings (e.g., holograms) that at least partially overlap within the same volume of grating medium (e.g., for diffracting different colors of light and/or light from a range of different input angles at one or more corresponding output angles). 
     Optical system  14 B may include collimating optics such as imaging optics  34 . Imaging optics  34  (sometimes referred to herein as imaging lens  34 ) may include one or more lens elements that help direct image light  22  towards waveguide  26 . If desired, display module  14 A may be mounted within support structure  20  of  FIG.  1    while optical system  14 B may be mounted between portions of support structure  20  (e.g., to form a lens that aligns with eye box  24 ). Other mounting arrangements may be used, if desired. 
     As shown in  FIG.  2   , display module  14 A may generate light  22  associated with image content to be displayed to eye box  24 . Light  22  may be collimated using a lens such as a lens in imaging optics  34 . Optical system  14 B may be used to present light  22  output from display module  14 A to eye box  24 . 
     Optical system  14 B may include one or more optical couplers such as input coupler  28 , cross-coupler  32 , and output coupler  30 . In the example of  FIG.  2   , input coupler  28 , cross-coupler  32 , and output coupler  30  are formed at or on waveguide  26 . Input coupler  28 , cross-coupler  32 , and/or output coupler  30  may be completely embedded within the substrate layers of waveguide  26 , may be partially embedded within the substrate layers of waveguide  26 , may be mounted to waveguide  26  (e.g., mounted to an exterior surface of waveguide  26 ), etc. 
     The example of  FIG.  2    is merely illustrative. One or more of these couplers (e.g., cross-coupler  32 ) may be omitted. Optical system  14 B may include multiple waveguides that are laterally and/or vertically stacked with respect to each other. Each waveguide may include one, two, all, or none of couplers  28 ,  32 , and  30 . Waveguide  26  may be at least partially curved or bent if desired. 
     Waveguide  26  may guide light  22  down its length via total internal reflection. Input coupler  28  may be configured to couple light  22  from display module  14 A (imaging optics  34 ) into waveguide  26 , whereas output coupler  30  may be configured to couple light  22  from within waveguide  26  to the exterior of waveguide  26  and towards eye box  24 . For example, display module  14 A may emit light  22  in direction +Y towards optical system  14 B. When light  22  strikes input coupler  28 , input coupler  28  may redirect light  22  so that the light propagates within waveguide  26  via total internal reflection towards output coupler  30  (e.g., in direction X). When light  22  strikes output coupler  30 , output coupler  30  may redirect light  22  out of waveguide  26  towards eye box  24  (e.g., back along the Y-axis). In scenarios where cross-coupler  32  is formed at waveguide  26 , cross-coupler  32  may redirect light  22  in one or more directions as it propagates down the length of waveguide  26 , for example. 
     Input coupler  28 , cross-coupler  32 , and/or output coupler  30  may be based on reflective and refractive optics or may be based on holographic (e.g., diffractive) optics. In arrangements where couplers  28 ,  30 , and  32  are formed from reflective and refractive optics, couplers  28 ,  30 , and  32  may include one or more reflectors (e.g., an array of micromirrors, partial mirrors, or other reflectors). In arrangements where couplers  28 ,  30 , and  32  are based on holographic optics, couplers  28 ,  30 , and  32  may include diffractive gratings (e.g., volume holograms, surface relief gratings, etc.). 
     It may be desirable to display high resolution images using display  14 . However, in practice, the human eye may only be sensitive enough to appreciate the difference between higher resolution and lower resolution image data near the center of its field of view (e.g., a user may be less sensitive to low resolution image data in portions of the image at the periphery of the user&#39;s field of view). In practice, providing high resolution image data within the entirety of the field of view may consume an excessive amount of processing resources, optical resources, and space within display  14 , particularly given that users are only sensitive to high resolution image data near the center of the field of view. Display  14  may therefore be a foveated display that displays only critical portions of an image at high resolution to help reduce the burdens on system  10 . 
     In general, increasing the physical size of display module  14 A (e.g., display panel  38  of  FIG.  3   ) will increase the maximum resolution of the images that can be displayed using light  22 . However, space is often at a premium in compact systems such as system  10  of  FIG.  1   . It would therefore be desirable to be able to provide high resolution images while also conserving processing and optical resources in system  10 , without further increasing the size of display module  14 A (e.g., display panel  38 ). 
     In order to provide high resolution images without undesirably burdening the resources of system  10  and without further increasing the size of display module  14 A, display module  14 A may be configured to perform dynamic foveation operations on light  22 . Display module  14 A may, for example, display portions of an image that are near the center of the user&#39;s field of view with higher resolution, whereas portions of the image that are far from the center of the user&#39;s field of view are displayed with lower resolution. As the user&#39;s gaze changes over time, display module  14 A may adjust the portions of the image that are produced with the higher resolution so that that portion remains at the center of the user&#39;s gaze. Gaze tracking components (e.g., image sensors in components  18  of  FIG.  1   ) may actively track the location of the user&#39;s gaze over time. Information about the direction of the user&#39;s gaze may be used to shift the location of the higher resolution portion of the image to follow the center of the user&#39;s gaze. The images in light  22  may thereby be foveated images (e.g., dynamically foveated images in which the higher resolution portions of the image are re-located over time to follow/track the user&#39;s gaze). 
       FIG.  3    is a diagram showing a foveated image that may be produced by display module  14 A. Light  22  of  FIG.  2    may include a foveated image such as foveated image  40  of  FIG.  3    (e.g., as produced by display module  14 A). Foveated image  40  may include pixels  43 . As shown in  FIG.  3   , foveated image  40  may include lower resolution pixels  43  in regions  42  (sometimes referred to herein as lower-resolution regions  42 , low-resolution regions  42 , or low-resolution portions  42 ) and higher resolution pixels  43  in region  44  (sometimes referred to herein as higher-resolution region  44 , high-resolution region  44 , or high-resolution portion  44 ). Display module  14 A may, for example, optically provide the pixels in regions  42  with higher magnification and thus lower resolution and lower pixel pitch while optically providing the pixels in region  44  with lower magnification and thus higher resolution and higher pixel pitch. Regions  42  may, for example, be peripheral regions that run around the periphery of region  44  (e.g., along the periphery of the field of view of the user&#39;s gaze at any given time). Region  44  may, for example, be located at the center of the user&#39;s gaze at any given time. Components  18  of  FIG.  1    may gather gaze tracking data that identifies the location of the user&#39;s gaze. As the direction of the user&#39;s gaze changes over time, control circuitry  16  ( FIG.  1   ) may adjust display module  14 A to shift the location of region  44  (e.g., based on the gaze tracking data) to align region  44  with the center of the user&#39;s gaze, as shown by arrows  46 . 
     Because foveated image  40  has a higher resolution within region  44  than within regions  42 , the user (e.g., at eye box  24  of  FIG.  2   ) may perceive foveated image  40  as a high resolution image (e.g., because the user&#39;s eye is sensitive to the higher resolution within region  44  and is insensitive to the lower resolution within regions  42 ). This may allow the images displayed at eye box  24  to effectively appear as high resolution images without requiring an increase in the size of display module  14 A or the processing and optical resources of system  10 , even if the user shifts the direction of their gaze over time (e.g., the foveation may be dynamically performed by display module  14 A without imposing any increased burden on the other components in system  10 ). The example of  FIG.  3    is merely illustrative. Regions  44  and  42  may have any desired shapes and/or sizes. Foveated image  40  may have any desired shape and/or size and may include any desired number of pixels  43  (sometimes referred to herein as image pixels  43 ). 
       FIG.  4    is a diagram of display module  14 A in an example where display module  14 A is a reflective-type display that produces foveated images such as dynamically foveated image  40  of  FIG.  3   . As shown in  FIG.  4   , display module  14 A may include an illumination source such as light source  50 . Light source  50  may have one or more light-emitting components (elements) for producing output light. The light-emitting elements may be, for example, light-emitting diodes (e.g., red, green, and blue light-emitting diodes, white light-emitting diodes, infrared light-emitting diodes, and/or light-emitting diodes of other colors), OLEDs, uLEDs, etc. Illumination may also be provided using light sources such as lasers (e.g., VCSELs) or lamps. 
     In the example of  FIG.  4   , display module  14 A is a reflective display module such as a liquid-crystal-on-silicon (LCOS) display module, a microelectromechanical systems (MEMs) display module (sometimes referred to as digital micromirror devices (DMDs)), or other display module (e.g., spatial light modulators). An optical component such as prism  62  may be optically interposed between light source  50  and reflective display panel  66 . Reflective display panel  66  is a reflective spatial light modulator and may be, for example, an LCOS display panel, a DMD panel (e.g., a panel having an array of micromirrors each corresponding to a given display pixel), etc. 
     Display module  14 A may include primary optics  88  and secondary optics  86 . Primary optics  88  (sometimes referred to herein as lower resolution optics  88  or low resolution optics  88 ) may include reflective display panel  66 , prism  62 , lens  60 , mirror  58 , and lens  56 . Lens  60  may include one or more lens elements arranged in any desired manner Lens  56  may include one or more lens elements arranged in any desired manner Prism  62  may include a polarizing beam splitter such as polarizing beam splitter  64 . Polarizing beam splitter  64  may transmit a first polarization of light while reflecting a second polarization of light. Secondary optics  86  (sometimes referred to herein as higher resolution optics  86  or high resolution optics  88 ) may include lens  74 , optical steering element  76  (sometimes referred to herein as steerable element  76  or steerable optical element  76 ), mirror  80 , and lens  81 . Display module  14 A may also include lens  52  and beam splitter  54  (e.g., a half-mirror beam splitter). Lens  52  may include one or more lens elements arranged in any desired manner Lens  74  may include one or more lens elements arranged in any desired manner Lens  81  may include one or more lens elements arranged in any desired manner Lenses  60 ,  56 ,  81 , and/or  52  may be omitted if desired. Display module  14 A may include other optical components (e.g., polarizers, beam splitters, mirrors, wave plates, optical coatings, lenses, lens elements, etc.) if desired. 
     Display module  14 A of  FIG.  4    may produce foveated image  40  of  FIG.  3    using multiple different optical paths (e.g., a first optical path for producing low-resolution regions  42  and a second optical path that is different from the first optical path for producing high-resolution region  44 ). For example, a first optical path running from light source  50  to imaging optics  34  through primary optics  88  may be used produce low-resolution regions  42  of foveated image  40  whereas a second optical path running from light source  50  to imaging optics  34  through both primary optics  88  and secondary optics  86  may be used to produce high-resolution region  44  of foveated image  40 . Display module  14 A may produce alternating image frames using light following the first and second optical paths (e.g., such that only one of high-resolution region  44  or low-resolution regions  42  is displayed at any given time). Display module  14 A may alternate between the first and second optical paths at a sufficiently high rate such that it appears to a user as though both high-resolution region  44  and low-resolution regions  42  of foveated image  40  are being displayed concurrently. 
     For example, as shown in  FIG.  4   , light source  50  may produce illumination light  68  (e.g., illumination light that includes a combination of colors such as red, green, and blue light). Illumination light  68  may pass through lens  52  (e.g., a collimating lens), through beam splitter  54 , and through lens  56  to mirror  58 . Illumination light  68  may reflect off of mirror  58  and pass through lens  60  and prism  62  to reflective display panel  66 . If desired, a polarizer may be interposed along this optical path to provide illumination light  68  with a given polarization such that the light is transmitted through polarizing beam splitter  64  to reflective display panel  66 . In another suitable arrangement, a portion of illumination light  68  may pass through polarizing beam splitter  64  without additional polarizers optically interposed between prism  62  and light source  50 . 
     Illumination light  68  may be reflected off of different display pixels P on reflective display panel  66  to produce reflected light  68 ′. Reflection by reflective display panel  66  may change the polarization of the light (relative to illumination light  68 ) such that reflected light  68 ′ is then reflected by polarizing beam splitter  64  towards imaging optics  34  (rather than being transmitted by polarizing beam splitter  64 ). Reflected light  68 ′ passes through imaging optics  34  to waveguide  26  of  FIG.  2   . The light that follows this optical path (e.g., the first optical path as shown by light  68  and  68 ′) may produce low-resolution regions  42  of foveated image  40  of  FIG.  3    within a relatively large field of view  70  (e.g., a field of view that extends across the entire field of view of foveated image  40 ). 
     The illumination light may follow a different optical path (e.g., the second optical path) to produce high-resolution region  44  of  FIG.  3   . For example, when high-resolution region  44  is to be displayed, the polarization of the illumination light  68  reflected off of reflective display panel  66  may be adjusted (e.g., using a switchable polarizer interposed between prism  62  and reflective display panel  66  or elsewhere in the optical path) to produce reflected light  72  having a polarization that is transmitted by polarizing beam splitter  64 . Reflected light  72  is then transmitted by polarizing beam splitter  64  and reflected off of mirror  58  through lens  56 . Reflected light  72  then reflects off of beam splitter  54  and passes through lens  74 . Lens  74  may include de-magnifying lens elements that reduce the magnification of reflected light  72  (e.g., reflected light  72  may have half the magnification or less than as incident upon lens  74 ). This reduction in magnification may serve to reduce the size/pitch of the image pixels in reflected light  72 , thereby increasing the effective resolution of the light relative to reflected light  68 ′. Reflected light  72  that has passed through lens  74  may sometimes be referred to herein as de-magnified light. 
     Steerable element  76  may redirect reflected light  72  (e.g., the de-magnified light) in a desired direction. Steerable element  76  may be adjusted to move reflected light  72  to a desired location in foveated image  40 . For example, steerable element  76  may be placed in a first state at which reflected light  72  is steered (directed) in a first direction towards mirror  80 , as shown by arrow  82 . In this first state, the light is reflected off of mirror  80  and all of the image pixels in the light are focused within image  83  (sometimes referred to herein as foveal image  83  or high resolution image  83 ). This light is then transmitted through prism  62  and polarizing beam splitter  64  to imaging optics  34  and waveguide  26  of  FIG.  2   , where the light forms high-resolution region  44  at a first location within foveated image  40 . Similarly, steerable element  76  may be placed in a second state at which reflected light  72  is steered (directed) in a second direction towards mirror  80 , as shown by dashed arrow  84 . In this second state, the light is reflected off of mirror  80  and all of the image pixels in the light are focused within image  87  (sometimes referred to herein as foveal image  87  or high resolution image  87 ), which is spatially offset from image  83 . This light is then transmitted through prism  62  and polarizing beam splitter  64  to imaging optics  34  and waveguide  26  of  FIG.  2   , where the light forms high-resolution region  44  at a second location within foveated image  40 . By switching steerable element  76  between the first and second states, the location of high-resolution region  44  of foveated image  40  may be adjusted over time (e.g., as shown by arrows  46  in  FIG.  3   ). For example, this adjustment may be performed to re-align high-resolution region  44  with the center of the user&#39;s gaze as the user&#39;s gaze direction changes over time (e.g., based on gaze tracking data gathered by components  18  of  FIG.  1   ). If desired, optional polarizing elements may be interposed at any desired location(s) on the optical path of reflected light  72  to provide the light with a polarization that is transmitted by polarizing beam splitter  64  after passing through lens  81 . 
       FIG.  4    illustrates an example where steerable element  76  has only two states for the sake of clarity. In general, steerable element  76  may have any desired number of states for steering reflected light  72  and thus high-resolution region  44  to any desired number of locations within foveated image  40 . Steerable element  76  may be a liquid crystal steering element (e.g., an adjustable liquid crystal prism or other switchable liquid crystal steering device), an adjustable aperture, or any other desired steerable element that optically steers the direction of reflected light  72 . The state of steerable element  76  may, for example, be controlled by control signals received over control path  78  (e.g., from control circuitry  16  of  FIG.  1   ). This example is merely illustrative. In another suitable arrangement, steerable element  76  may be omitted and mirror  80  may be a steerable mirror (e.g., a MEMs mirror or other actuated mirror) that is steered to redirect reflected light  72  to different locations in foveated image  40 . The components of primary optics  88  and/or secondary optics  86  may be arranged in other manners if desired. The light associated with arrows (rays)  82  and  84  and reflected light  68 ′ may collectively form light  22  of  FIG.  2    (e.g., light that includes foveated image  40  of  FIG.  3   ). 
     In this way, display module  14 A may perform dynamic foveation operations by splitting illumination light  68  between a first optical path that extends through primary optics  88  (e.g., as shown by reflected light  68 ′) for producing low-resolution regions  42  of foveated image  40  and a second optical path that extends through secondary optics  86  in addition to primary optics  88  (e.g., as shown by reflected light  72  and arrows  82  and  84 ). Secondary optics  86  include a steerable element such as steerable element  76  for adjusting the location of high-resolution region  44  of foveated image  40  (e.g., so that the user continues to see a high resolution image at the center of their gaze regardless of their gaze direction over time). Because the remainder of the image is provided with a lower resolution (e.g., low-resolution regions  42 ), this may allow the user to perceive higher resolution images without undesirably increasing the size of reflective display panel  66  and prism  62  to accommodate all of the pixels that would otherwise be necessary to produce such high resolution images. 
     The example of  FIG.  4    in which display module  14 A includes a reflective display panel is merely illustrative. In another suitable arrangement, display module  14 A may include emissive display panels for producing foveated image  40 .  FIG.  5    is a diagram showing how display module  14 A may include emissive display panels. As shown in  FIG.  5   , primary optics  88  may include illumination optics  100 , prism  62 , and polarizing beam splitter  64 . Secondary optics  86  may include illumination optics  102 , lens  112 , mirror  114 , steerable element  76 , mirror  80 , and lens  81 . 
     Illumination optics  100  may include emissive display panels  106  and prism  110 . Emissive display panels  106  may include arrays of emissive light sources such as LEDs, OLEDs, uLEDs, lasers, etc. Emissive display panels  106  in illumination optics  100  may include a first emissive display panel  106 A, a second emissive display panel  106 B, and a third emissive display panel  106 C. Emissive display panels  106 A,  106 B, and  106 C may each emit illumination light  120  of a corresponding wavelength range (e.g., color). For example, emissive display panel  106 A may emit red light, emissive display panel  106 B may emit green light, and emissive display panel  106 C may emit blue light. Prism  110  may combine the light emitted by emissive display panels  106 A,  106 B, and  106 C into illumination light  120  (e.g., illumination light  120  may include red, green, and blue light, etc.). Illumination light  120  is reflected off of polarizing beam splitter towards illumination optics  34 . Polarizers may be interposed on the optical path of illumination light  120  (e.g., between the arrays of light sources and prism  110 , between prism  62  and prism  110 , etc.) to provide illumination light  120  with a given polarization that is reflected (rather than transmitted) by polarizing beam splitter  64 . Emissive display panels  106 A,  106 B, and  106 C may each include arrays of display pixels P (e.g., where each emissive light source in the panel forms a respective display pixel). Display pixels P produce the image pixels  43  of low-resolution regions  42  in foveated image  40  of  FIG.  3    (e.g., illumination light  120  may form low-resolution regions  42  of foveated image  40  in the light  22  that is provided to waveguide  26  of  FIG.  2   ). 
     Illumination optics  102  may include emissive display panels  104  and prism  108 . Emissive display panels  104  may include arrays of emissive light sources such as LEDs, OLEDs, uLEDs, uOLEDs, lasers (e.g., VCSELs), etc. Emissive display panels  104  in illumination optics  102  may include a first emissive display panel  104 A, a second emissive display panel  104 B, and a third emissive display panel  104 C. Emissive display panels  104 A,  104 B, and  104 C may each emit illumination light  122  of a corresponding wavelength range (e.g., color). For example, emissive display panel  104 A may emit red light, emissive display panel  104 B may emit green light, and emissive display panel  104 C may emit blue light. Emissive display panels  104 A,  104 B, and  104 C may each include arrays of display pixels P (e.g., where each emissive light source in the panel forms a respective pixel). Display pixels P produce the image pixels  43  of high-resolution region  44  in foveated image  40  (e.g., illumination light  120  may form high-resolution region  44  of foveated image  40  in the light  22  that is provided to waveguide  26  of  FIG.  2   ). 
     Prism  108  may combine the light emitted by emissive display panels  104 A,  104 B, and  104 C into illumination light  122  (e.g., illumination light  122  may include red, green, and blue light, etc.). Illumination light  122  is transmitted through lens  112 . Lens  112  may include de-magnifying lens elements that reduce the magnification of illumination light  122  (e.g., illumination light  122  may have half the magnification or less after passing through lens  112  than as incident upon lens  112 ). This reduction in magnification may serve to reduce the size/pitch of the image pixels in illumination light  122 , thereby increasing the effective resolution of the light (relative to illumination light  120 ). After de-magnification by lens  112 , illumination light  122  is reflected off of mirror  114  towards steerable element  76 . 
     Steerable element  76  may redirect illumination light  122  in a desired direction. Steerable element  76  may be adjusted to move illumination light  122  to a desired location in foveated image  40 . For example, steerable element  76  may be placed in a first state at which illumination light  122  is steered (directed) in a first direction towards mirror  80 , as shown by arrow  124 . In this first state, the light is reflected off of mirror  80  and all of the image pixels in the light are focused within image  83 . This light is then transmitted through prism  62  and polarizing beam splitter  64  to imaging optics  34  and waveguide  26  of  FIG.  2    (e.g., the light following arrow  124  may have a polarization that is transmitted by polarizing beam splitter  64 ), where the light forms high-resolution region  44  at a first location within foveated image  40 . Similarly, steerable element  76  may be placed in a second state at which illumination light  122  is steered (directed) in a second direction towards mirror  80 , as shown by dashed arrow  126 . In this second state, the light is reflected off of mirror  80  and all of the image pixels in the light are focused within image  87 , which is spatially offset from image  83 . This light is then transmitted through prism  62  and polarizing beam splitter  64  to imaging optics  34  and waveguide  26  of  FIG.  2    (e.g., the light following arrow  124  may have a polarization that is transmitted by polarizing beam splitter  64 ), where the light forms high-resolution region  44  at a second location within foveated image  40 . By switching steerable element  76  between the first and second states, the location of high-resolution region  44  of foveated image  40  may be adjusted over time (e.g., as shown by arrows  46  in  FIG.  3   ). For example, this adjustment may be performed to re-align high-resolution region  44  with the center of the user&#39;s gaze as the user&#39;s gaze changes over time (e.g., based on gaze tracking data gathered by components  18  of  FIG.  1   ). If desired, optional polarizing elements may be interposed at any desired location(s) on the optical path of illumination light  122  to provide illumination light  122  with a polarization that is transmitted by polarizing beam splitter  64 . 
       FIG.  5    illustrates an example where steerable element  76  has only two states for the sake of clarity. In general, steerable element  76  may have any desired number of states for steering reflected light  72  and thus high-resolution region  44  to any desired number of locations within foveated image  40 . Steerable element  76  may be a liquid crystal steering element (e.g., an adjustable liquid crystal prism), an adjustable aperture, or any other desired steerable element that steers the direction of reflected light  72 . The state of steerable element  76  may, for example, be controlled by control signals received over control path  78  (e.g., from control circuitry  16  of  FIG.  1   ). This example is merely illustrative. In another suitable arrangement, steerable element  76  may be omitted and mirror  80  may be a steerable mirror (e.g., a MEMs mirror or other actuated mirror) that is steered to redirect illumination light  122  to different locations in foveated image  40 . The components of primary optics  88  and/or secondary optics  86  may be arranged in other manners if desired. 
     Forming primary optics  88  and secondary optics  86  using emissive display panels rather than reflective display panels may allow display module  14 A to concurrently display both the high-resolution region  44  of foveated image  40  (e.g., using secondary optics  86 , primary optics  88 , and illumination light  122 ) and the low-resolution regions  42  of foveated image  40  (e.g., using primary optics  88  and illumination light  120 ), whereas the reflective display module of  FIG.  4    only displays either the high resolution region or the low resolution regions at any given time while alternating between the two faster than the response speed of the human eye. Even though emissive display panels are used in  FIG.  5    rather than reflective display panels, display module  14 A still performs dynamic foveation operations by splitting illumination light  68  between a first optical path that extends through primary optics  88  (e.g., as shown by illumination light  120 ) for producing low-resolution regions  42  of foveated image  40  and a second optical path that extends through secondary optics  86  in addition to primary optics  88  (e.g., as shown by illumination light  122  and rays  124  and  126 ). Secondary optics  86  include a steerable element such as steerable element  76  for adjusting the location of high-resolution region  44  of foveated image  40  (e.g., so that the user continues to see a high resolution image at the center of their gaze regardless of their gaze direction over time). Because the remainder of the image is provided with a lower resolution (e.g., low-resolution regions  42 ), this may allow the user to perceive higher resolution images without undesirably increasing the size of reflective display panel  66  and prism  62  to accommodate all of the pixels that would otherwise be necessary to produce such high resolution images. 
     For example, even though display module  14 A of  FIGS.  4  and  5    include secondary optics  86  in addition to primary optics  88  for generating image light with high-resolution region  44 , the volume of secondary optics  86  in addition to the volume of primary optics  88  is still less than the volume that would otherwise be required if reflective display panel  66  ( FIG.  4   ) or emissive display panels  106 A- 106 C ( FIG.  5   ) were to be modified to include sufficient space to fill the entire field of view of image  40  with pixels of the same resolution as high-resolution region  44 . By performing dynamic foveation in which high-resolution region  44  tracks the user&#39;s gaze over time, the image presented to the user at the eye box effectively appears the same to the user as if the entire image were generated with higher resolution pixels. This may serve to optimize the apparent image quality of the display to the user while also allowing display module  14 A to occupy a relatively small amount of volume, thereby minimizing the volume of system  10 . 
     If desired, emissive display panels  104  and  106  of  FIG.  5    may be replaced with front-illuminated reflective display panels.  FIG.  6    is a diagram of a front-illuminated reflective display panel that may be used to replace one or more of emissive display panels  106 A,  106 B,  106 C,  104 A,  104 B, and  104 C of  FIG.  5   . As shown in  FIG.  6   , front-illuminated reflective display panel  145  may include a reflective display panel  140 , a light guide  142  overlapping reflective display panel  140 , and light sources  144 . Reflective display panel  140  may be an LCOS panel or other reflective display panel. Light sources  144  may, for example, include LEDs (e.g., red, green, and blue LEDs). Light sources  144  may emit light  146  into light guide  142  (e.g., via a side edge or input face of light guide  142 ). Light  146  may propagate down the length of light guide  142  via total internal reflection. Light  146  may be coupled out of light guide  142  and towards reflective display panel  140  at different points along the length (area) of light guide  142  (e.g., when the incident angle of the light no longer supports total internal reflection or when the light encounters output coupling features on or in light guide  142 ). Light  146  may reflect off of different display pixels P in reflective display panel  140  and towards prism  110  or prism  108  of  FIG.  5    (e.g., as a portion of illumination light  120  or  122  of  FIG.  5   ). 
     In accordance with an embodiment, a display system configured to display a foveated image having a first region with a first resolution and a second region with a second resolution greater than the first resolution, the display system is provided that includes an optical system configured to direct the foveated image towards an eye box, a light source that produces illumination light, a reflective display panel, during a first time period, the reflective display panel is configured to reflect the illumination light as first reflected light, and during a second time period different from the first time period, the reflective display panel is configured to reflect the illumination light as second reflected light, a polarizing beam splitter, the polarizing beam splitter is configured to reflect the first reflected light towards the optical system as the first region of the foveated image, and the polarizing beam splitter is configured to transmit the second reflected light, a lens configured to de-magnify the second reflected light transmitted by the polarizing beam splitter to produce de-magnified light, and an optical steering element configured to re-direct the de-magnified light through the polarizing beam splitter and towards the optical system as the second region of the foveated image. 
     In accordance with another embodiment, the display system includes control circuitry, the control circuitry is configured to adjust the optical steering element to change a location of the second region in the foveated image. 
     In accordance with another embodiment, the optical steering element includes an adjustable mirror. 
     In accordance with another embodiment, the display system includes a mirror, the optical steering element is configured to re-direct the de-magnified light towards the mirror and the mirror is configured to reflect the de-magnified light through the polarizing beam splitter and towards the optical system as the second region of the foveated image. 
     In accordance with another embodiment, the optical steering element includes a switchable liquid crystal steering device. 
     In accordance with another embodiment, the display system includes a gaze tracking sensor, the gaze tracking sensor is configured to gather gaze tracking data that identifies a gaze direction at the eye box, and the control circuitry is configured to adjust the optical steering element to align the location of the second region with the gaze direction identified by the gaze tracking data. 
     In accordance with another embodiment, the reflective display panel includes a liquid crystal on silicon (LCOS) display panel. 
     In accordance with another embodiment, the reflective display panel includes a digital-micromirror device display panel. 
     In accordance with another embodiment, the display system includes a mirror, the mirror is configured to reflect the illumination light towards the polarizing beam splitter and the mirror is configured to reflect the second reflected light transmitted by the polarizing beam splitter towards the lens, and a partial mirror, the partial mirror is configured to transmit the illumination light, the partial mirror is configured to receive the second reflected light from the mirror, and the partial mirror is configured to reflect the second reflected light towards the lens. 
     In accordance with another embodiment, the lens is optically interposed between the partial mirror and the optical steering element, the mirror is optically interposed between the partial mirror and the polarizing beam splitter, and the polarizing beam splitter is optically interposed between the mirror and the reflective display panel. 
     In accordance with another embodiment, the optical system includes a waveguide having an input coupler configured to couple the foveated image into the waveguide and an output coupler configured to couple the foveated image out of the waveguide and towards the eye box. 
     In accordance with another embodiment, the first reflected light does not pass through the lens and is not redirected by the optical steering element. 
     In accordance with an embodiment, a display system configured to display a foveated image having a first region with a first resolution and a second region with a second resolution greater than the first resolution, the display system is provided that includes an optical system configured to direct the foveated image towards an eye box, a polarizing beam splitter, a first set of emissive display panels configured to produce first illumination light, the polarizing beam splitter is configured to reflect the first illumination light towards the optical system as the first region of the foveated image, a second set of emissive display panels configured to produce second illumination light, a lens configured to de-magnify the second illumination light to produce de-magnified light, and an optical steering element configured to re-direct the de-magnified light towards the polarizing beam splitter, the polarizing beam splitter is configured to transmit the de-magnified light re-directed by the optical steering element, and the de-magnified light re-directed by the optical steering element forms the second region of the foveated image. 
     In accordance with another embodiment, the optical steering element has a first state at which the de-magnified light is re-directed in a first direction and at which the second region is at a first location in the foveated image, and the optical steering element has a second state at which the de-magnified light is re-directed in a second direction different from the first direction and at which the second region is at a second location in the foveated image that is different from the first location. 
     In accordance with another embodiment, the display system includes control circuitry configured to control the optical steering element to switch between the first and second states. 
     In accordance with another embodiment, the first set of emissive display panels includes first, second, and third micro light-emitting-diode (uLED) arrays, and the second set of emissive display panels includes fourth, fifth, and sixth uLED arrays. 
     In accordance with another embodiment, the first set of emissive display panels includes first, second, and third laser arrays, and the second set of emissive display panels includes fourth, fifth, and sixth laser arrays. 
     In accordance with another embodiment, the display system includes a first mirror configured to receive the de-magnified light from the lens and configured to reflect the de-magnified illumination light towards the optical steering element, and a second mirror configured to receive the de-magnified light re-directed by the optical steering element and configured to reflect the de-magnified light towards the polarizing beam splitter. 
     In accordance with an embodiment, a display system configured to display a foveated image having a first region with a first resolution and a second region with a second resolution greater than the first resolution, the display system is provided that includes an optical system configured to direct the foveated image towards an eye box, a polarizing beam splitter, a first set of front-lit reflective display panels configured to produce first illumination light, the polarizing beam splitter is configured to reflect the first illumination light towards the optical system as the first region of the foveated image, a second set of front-lit reflective display panels configured to produce second illumination light, a lens configured to de-magnify the second illumination light to produce de-magnified light, and an optical steering element configured to re-direct the de-magnified light towards the optical system through the polarizing beam splitter, the de-magnified light re-directed by the optical steering element forms the second region of the foveated image. 
     In accordance with another embodiment, each front-lit reflective display panels in the first set includes a liquid crystal on silicon (LCOS) display panel, a light source that produces light, and a light guide that propagates the light produced by the light source via total internal reflection, the light guide is configured to couple the light produced by the light source out of the light guide and towards the LCOS display panel, and the LCOS display panel is configured to produce the first illumination light by reflecting the light coupled out of the light guide. 
     The foregoing is merely illustrative and various modifications can be made to the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20210920
Publication Date: 20231226
Grant Date: 20231226
Priority Date: 20191122
Inventors: MYHRE, GRAHAM B.
PENG, GUOLIN
CHOI, Hyungryul
DELAPP, SCOTT M.
BHAKTA, Vikrant
Assignee: APPLE INC
CPC Classifications: [{"code": "G02B27/0172", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B27/0093", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B27/283", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B27/1066", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B2027/014", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B2027/0138", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B2027/0147", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B27/0172", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B27/0093", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B27/0172", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B27/283", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B27/0093", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B2027/0138", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B2027/014", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B2027/0147", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B27/0172", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B2027/0138", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B2027/0147", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B27/1066", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B27/283", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B2027/014", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B27/0093", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B2027/014", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B2027/0147", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B27/1066", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B27/283", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B2027/0138", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 73790246