PATENT DOCUMENT

Publication Number: US-11175503-B2
Application Number: US-201916262741-A
Country: US
Kind Code: B2

Title: Optical system for head-mounted display

Abstract:
A head-mounted display may include a display system and a lens system in a housing. The head-mounted display may include control circuitry that operates the head-mounted display in an active use mode and a protected mode. In the protected mode, the display system may be protected from collisions with the lens system. Placing the head-mounted display in the protected mode may include using an actuator to increase the distance between the display system and the lens system, may include injecting fluid between the display system and the lens system, and/or may include deploying a protective layer between the display system and the lens system. The control circuitry may determine whether to operate the head-mounted display in protected mode or active use mode based on sensor data, on/off status information, location information, and/or other information.

Claims:
What is claimed is: 
     
       1. A head-mounted display configured to display images viewable by a user, comprising:
 a display system including an array of pixels configured to produce the images; 
 a lens system through which the images are viewable, wherein the display system and the lens system are separated by a distance; 
 a sensor that produces sensor data, wherein the sensor comprises a motion sensor; and 
 control circuitry that adjusts the distance based on the sensor data to protect the display system, wherein the control circuitry increases the distance when the sensor data from the motion sensor indicates that the head-mounted display is in freefall. 
 
     
     
       2. The head-mounted display defined in  claim 1  wherein the control circuitry decreases the distance when the sensor data from the motion sensor indicates that the head-mounted display has been placed on the user&#39;s head. 
     
     
       3. The head-mounted display defined in  claim 1  wherein the control circuitry increases the distance when the sensor data from the motion sensor indicates that the head-mounted display has been removed from the user&#39;s head. 
     
     
       4. The head-mounted display defined in  claim 1  wherein the sensor comprises a camera. 
     
     
       5. The head-mounted display defined in  claim 4  wherein the control circuitry increases the distance when the sensor data from the camera indicates that the head-mounted display has been removed from the user&#39;s head. 
     
     
       6. The head-mounted display defined in  claim 4  wherein the control circuitry decreases the distance when the sensor data from the camera indicates that the head-mounted display has been placed on the user&#39;s head. 
     
     
       7. The head-mounted display defined in  claim 4  wherein the control circuitry increases the distance when the sensor data from the camera indicates that an external object is approaching the head-mounted display. 
     
     
       8. The head-mounted display defined in  claim 1  further comprising an actuator, wherein the control circuitry uses the actuator to adjust the distance between the display system and the lens system. 
     
     
       9. The head-mounted display defined in  claim 8  wherein the actuator moves the display system while the lens system remains fixed. 
     
     
       10. The head-mounted display defined in  claim 8  wherein the actuator moves the lens system while the display system remains fixed. 
     
     
       11. The head-mounted display defined in  claim 8  wherein the lens system comprises at least first and second lenses, wherein the second lens is interposed between the first lens and the display system, and wherein the actuator moves the second lens while the first lens and the display system remain fixed. 
     
     
       12. The head-mounted display defined in  claim 1  further comprising a housing having an opening through which fluid passes to adjust the distance between the display system and the lens system. 
     
     
       13. A head-mounted display configured to display images viewable by a user and configured to be powered on and off, comprising:
 a display system including an array of pixels configured to produce the images; 
 a lens system through which the images are viewable, wherein the lens system and the display system are separated by a distance; 
 an actuator; and 
 control circuitry that uses the actuator to increase the distance when the head-mounted display is powered off and decrease the distance when the head-mounted display is powered on, and wherein the display system and the lens system overlap each other when the head-mounted display is powered off and when the head-mounted display is powered on. 
 
     
     
       14. The head-mounted display defined in  claim 13  wherein the lens system has an optical axis and wherein the control circuitry uses the actuator to move at least one of the display system and the lens system along the optical axis. 
     
     
       15. The head-mounted display defined in  claim 13  wherein the lens system has an apex and wherein the control circuitry uses the actuator to rotate the display system away from the apex to increase the distance. 
     
     
       16. A head-mounted display configured to display images viewable by a user, wherein the head-mounted display is operable in an active use mode and a protected mode, comprising:
 a display system including an array of pixels configured to produce the images; 
 a lens system through which the images are viewable; 
 an accelerometer that produces motion data; and 
 control circuitry that determines whether to operate the head-mounted display in the active use mode or the protected mode based on the motion data, wherein the display system is protected from collisions with the lens system when the head-mounted display is in the protected mode. 
 
     
     
       17. The head-mounted display defined in  claim 16  further comprising a protective layer, wherein the control circuitry deploys the protective layer between the display system and the lens system when the head-mounted display is in the protected mode. 
     
     
       18. The head-mounted display defined in  claim 16  further comprising an actuator, wherein the control circuitry uses the actuator to increase a distance between the display system and the lens system when the head-mounted display is in the protected mode.

Description:
This application claims the benefit of provisional patent application No. 62/677,581, filed May 29, 2018, which is hereby incorporated by reference herein in its entirety. 
    
    
     FIELD 
     This relates generally to optical systems and, more particularly, to optical systems for head-mounted displays. 
     BACKGROUND 
     Head-mounted displays such as virtual reality glasses use lenses to display images for a user. A display may create images for each of a user&#39;s eyes. A lens may be placed between each of the user&#39;s eyes and a portion of the display so that the user may view virtual reality content. 
     If care is not taken, a head-mounted display may be vulnerable to damage. An optical system in the head-mounted display may include a lens directly adjacent to a display, which runs the risk of unwanted collisions between the lens and the display in the event that the head-mounted display is dropped or hit by an external object. Such collisions can damage the lens and the display in the head-mounted device. 
     It would therefore be desirable to be able to provide improved head-mounted displays. 
     SUMMARY 
     A head-mounted display may include a display system and a lens system. The display system and lens system may be supported by a housing that is worn on a user&#39;s head. The head-mounted display may use the display system and lens system to present images to the user while the housing is being worn on the user&#39;s head. The display system may include a pixel array that produces images that are viewable through the lens system. 
     The head-mounted display may include control circuitry that operates the head-mounted display in an active use mode and a protected mode. In the protected mode, the display system may be protected from collisions with the lens system. Placing the head-mounted display in the protected mode may include using an actuator to increase the distance between the display system and the lens system (e.g., by moving one or both of the display system and the lens system away from each other), may include injecting fluid between the display system and the lens system, and/or may include deploying a protective layer between the display system and the lens system. The control circuitry may determine whether to operate the head-mounted display in protected mode or active use mode based on sensor data, on/off status information, location information, and/or other information. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram of an illustrative head-mounted display in accordance with an embodiment. 
         FIG. 2  is a diagram of an illustrative head-mounted display having a lens system, a display system, and an actuator for adjusting a distance between the lens system and the display system in accordance with an embodiment. 
         FIG. 3  is a side view of an illustrative head-mounted display in active use mode in accordance with an embodiment. 
         FIG. 4  is a side view of an illustrative head-mounted display in protected mode in accordance with an embodiment. 
         FIG. 5  is a side view of an illustrative head-mounted display having a lens system with an interposer lens in active use mode in accordance with an embodiment. 
         FIG. 6  is a side view of an illustrative head-mounted display having a lens system with an interposer lens in protected mode in accordance with an embodiment. 
         FIG. 7  is a side view of an illustrative head-mounted display having a display system that is rotated relative to a lens system to shift between active use mode and protected mode in accordance with an embodiment. 
         FIG. 8  is a side view of an illustrative head-mounted display having a lens system that is moved laterally relative to a display system to shift between active use mode and protected mode in accordance with an embodiment. 
         FIG. 9  is a cross-sectional view of an illustrative head-mounted display in which fluid such as air is injected between a display system and a lens system to shift between active use mode and protected mode in accordance with an embodiment. 
         FIG. 10  is a side view of an illustrative head-mounted display having a protective layer deployed between a display system and a lens system to shift between active use mode and protected mode in accordance with an embodiment. 
         FIG. 11  is a flow chart of illustrative steps involved in operating a head-mounted display in active use mode and protected mode in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Head-mounted displays may be used for virtual reality and augmented reality systems. For example, a pair of virtual reality glasses that is worn on the head of a user may be used to provide a user with virtual reality content. 
     An illustrative system in which a head-mounted display such as a pair of virtual reality glasses is used in providing a user with virtual reality content is shown in  FIG. 1 . As shown in  FIG. 1 , virtual reality glasses (head-mounted display)  10  may include a display system such as display system  12  that creates images and may have an optical system such as lens system  14  through which a user (see, e.g., user&#39;s eyes  16 ) may view the images produced by display system  12  by looking in direction  18 . 
     Display system  12  may be based on a liquid crystal display (e.g., liquid-crystal-on-silicon), an organic light-emitting diode display, an emissive display having an array of crystalline semiconductor light-emitting diode dies, and/or displays based on other display technologies. Separate left and right displays may be included in system  12  for the user&#39;s left and right eyes or a single display may span both eyes. 
     Visual content (e.g., image data for still and/or moving images) may be provided to display system (display)  12  using control circuitry  20  that is mounted in glasses (head-mounted display)  10  and/or control circuitry that is mounted outside of glasses  10  (e.g., in an associated portable electronic device, laptop computer, or other computing equipment). Control circuitry  20  may include storage such as hard-disk storage, volatile and non-volatile memory, electrically programmable storage for forming a solid-state drive, and other memory. Control circuitry  20  may also include one or more microprocessors, microcontrollers, digital signal processors, graphics processors, baseband processors, application-specific integrated circuits, and other processing circuitry. Control circuitry  20  may use display system  12  to display visual content such as virtual reality content (e.g., computer-generated content associated with a virtual world), pre-recorded video for a movie or other media, or other images. Illustrative configurations in which control circuitry  20  provides a user with virtual reality content using display system  12  may sometimes be described herein as an example. In general, however, any suitable content may be presented to a user by control circuitry  20  using display system  12  and lens system  14  of glasses  10 . 
     Communications circuits in circuitry  20  such as communications circuitry  80  may be used to transmit and receive data (e.g., wirelessly and/or over wired paths). Communications circuitry  80  may include wireless communication circuitry such as one or more antennas and associated radio-frequency transceiver circuitry. Transceiver circuitry in communications circuitry  80  may include wireless local area network transceiver circuitry (e.g., WiFi® circuitry), Bluetooth® circuitry, cellular telephone transceiver circuitry, ultra-wideband communications transceiver circuitry, millimeter wave transceiver circuitry, near-field communications circuitry, satellite navigation system circuitry such as Global Positioning System (GPS) receiver circuitry (e.g., for receiving GPS signals at 1575 MHz or for handling other satellite positioning data), and/or wireless circuitry that transmits and/or receives signals using light (e.g., with light-emitting diodes, lasers, or other light sources and corresponding light detectors such as photodetectors). Antennas in communications circuitry  80  may include monopole antennas, dipole antennas, patch antennas, inverted-F antennas, loop antennas, slot antennas, other antennas, and/or antennas that include antenna resonating elements of more than one type (e.g., hybrid slot-inverted-F antennas, etc.). 
     If desired, control circuitry  20  may determine the location of glasses  10  using communications circuitry  80 . For example, control circuitry  20  may determine the location of glasses  10  by processing wireless signals (e.g., ultra-wideband signals, Bluetooth® signals, WiFi® signals, millimeter wave signals, or other suitable signals) using signal strength measurement schemes, time based measurement schemes such as time of flight measurement techniques, time difference of arrival measurement techniques, angle of arrival measurement techniques, triangulation methods, time-of-flight methods, using a crowdsourced location database, and/or other suitable measurement techniques. If desired, control circuitry  20  may determine the location of glasses  10  using Global Positioning System receiver circuitry in circuitry  80  and/or using sensors  24  such as proximity sensors (e.g., infrared proximity sensors or other proximity sensors), depth sensors (e.g., structured light depth sensors that emit beams of light in a grid, a random dot array, or other pattern, and that have image sensors that generate depth maps based on the resulting spots of light produced on target objects), sensors that gather three-dimensional depth information using a pair of stereoscopic image sensors, lidar (light detection and ranging) sensors, radar sensors, using image data from a camera, using motion sensor data, and/or using other circuitry in glasses  10 . 
     Input-output devices  22  may be coupled to control circuitry  20 . Input-output devices  22  may be used to gather user input from a user, may be used to make measurements on the environment surrounding glasses  10 , may be used to provide output to a user, and/or may be used to supply output to external electronic equipment. Input-output devices  22  may include buttons, joysticks, keypads, keyboard keys, touch sensors, track pads, displays, touch screen displays, microphones, speakers, light-emitting diodes for providing a user with visual output, and/or other input-output circuitry. 
     Input-output devices  22  may include sensors  24 . Sensors  24  may include force sensors, temperature sensors, magnetic sensors, proximity sensors, capacitive touch sensors, strain gauges, gas sensors, pressure sensors, and/or other sensors. For example, sensors  24  may include a color ambient light sensor or other ambient light sensor  26  for gathering ambient light measurements (e.g., ambient light levels such as ambient light luminance measurements and/or ambient light color measurements such as color temperature measurements and/or color coordinate measurements). Ambient light sensors  26  may include inward facing ambient light sensors (e.g., facing eyes  16 ) and/or outward facing ambient light sensors (e.g., facing the environment in front of the user). 
     Sensors  24  may include one or more cameras  28  (e.g., digital image sensors) including cameras for capturing images of the user&#39;s surroundings, cameras for performing gaze detection operations by viewing eyes  16 , and/or other cameras. Cameras  28  may include inward facing cameras (e.g., facing eyes  16 ) and/or outward facing cameras (e.g., facing the environment in front of the user). 
     Sensors  24  may include one or more motion sensors  30 . Motion sensors  30  may include one or more accelerometers, compasses, gyroscopes, barometers, pressure sensors, magnetic sensors, inertial measurement units that contain some or all of these sensors, and/or other sensors for measuring orientation, position, and/or movement of glasses  10 . Motion sensors  30  may produce sensor data that indicates whether glasses  10  are in freefall and/or whether glasses  10  are being removed from or placed on a user&#39;s head. For example, an upward motion arc or lifting from a surface may indicate glasses  10  are being placed on or have been placed on a user&#39;s head, whereas a downward motion arc or setting down onto a surface may indicate that glasses  10  are being removed or have been removed from a user&#39;s head. 
       FIG. 2  is a cross-sectional side view of glasses  10  showing how lens system  14  and display system  12  may be supported by head-mounted support structures such as housing  32  for glasses  10 . Housing  32  may have the shape of a frame for a pair of glasses (e.g., glasses  10  may resemble eyeglasses), may have the shape of a helmet (e.g., glasses  10  may form a helmet-mounted display), may have the shape of a pair of goggles, or may have any other suitable housing shape that allows housing  32  to be worn on the head of a user. Configurations in which housing  32  supports lens system  14  and display system  12  in front of a user&#39;s eyes (e.g., eyes  16 ) as the user is viewing system  14  and display system  12  in direction  18  may sometimes be described herein as an example. If desired, housing  32  may have other suitable configurations. 
     Housing  32  may be formed from plastic, metal, fiber-composite materials such as carbon-fiber materials, wood and other natural materials, fabric, glass, silicone, other materials, and/or combinations of two or more of these materials. 
     Input-output devices  22  and control circuitry  20  may be mounted in housing  32  with lens system  14  and display system  12  and/or portions of input-output devices  22  and control circuitry  20  may be coupled to glasses  10  using a cable, wireless connection, or other signal paths. 
     Display system  12  may include a source of images such as pixel array  34 . Pixel array  34  may include a two-dimensional array of pixels P that emit image light. Pixels P may be liquid-crystal-on-silicon pixels (e.g., with a frontlight), organic light-emitting diode pixels, light-emitting diode pixels formed from semiconductor dies, liquid crystal display pixels with a backlight, etc.). Display system  12  may include additional layers such as additional layers  36 . Additional layers  36  may include one or more polarizers (e.g., one or more linear polarizers, to provide polarized image light), one or more wave plates (e.g., a quarter wave plate to provide circularly polarized image light), one or more optical films, and/or other layers. 
     Lens system  14  may include one or more lenses. Lenses in lens system  14  may include one or more plano-convex lenes (e.g., a first plano-convex lens having a convex surface  62  facing display system  12  and a second plano-convex lens having a concave surface  64  facing eyes  16 ). This is, however, merely illustrative. Other lens arrangements may be used in lens system  14 , if desired. Lens system  14  may include one lens, two lenses, three lenses, or more than three lenses. 
     Optical structures such as partially reflective coatings, wave plates, reflective polarizers, linear polarizers, antireflection coatings, and/or other optical components may be incorporated into glasses  10  (e.g., system  14 , etc.). These optical structures may allow light rays from display system  12  to pass through and/or reflect from surfaces in lens system  14  to provide lens system  14  with a desired lens power. 
     As shown in  FIG. 2 , glasses  10  may include one or more actuators such as actuators  38 . Actuators  38  may be linear or rotational and may include electric actuators, mechanical actuators, electromechanical actuators, pneumatic actuators, hydraulic actuators, and/or other suitable actuators. Actuators  38  may be used to adjust the distance D between lens system  14  and display system  12 . Control circuitry  20  may, if desired, use actuators  38  to adjust distance D to accommodate the user&#39;s eye prescription (e.g., to accommodate different diopter ranges). For example, control circuitry  20  may adjust distance D to one value according to the prescription of a first user and may adjust distance D to another value according to the prescription of a second user. To achieve the desired distance D, actuator  38  may be configured to move lens system  14  along the Z-axis while display system  12  remains fixed, may be configured to move display system  12  along the Z-axis while lens system  14  remains fixed, and/or may be configured to move both lens system  14  and display system  12  along the Z-axis. 
     If desired, control circuitry  20  may also use actuators  38  to move lens system  14  and/or display system  12  along the Y-axis to accommodate different interpupillary distances associated with different viewers. Control circuitry  20  may measure the interpupillary distance of each viewer by capturing images of the viewer&#39;s eyes with camera  28  or other sensors and processing the resulting eye position data to extract information on the locations of the viewers pupils. Control circuitry  20  may match the distance between the centers of left and right lens systems  14  to the measured interpupillary distance. 
     If desired, actuators  38  may be configured to move display system  12  and/or lens system  14  in other ways. In general, actuators  38  may be configured to move display system  12  and/or lens system  14  in any suitable fashion (e.g., linearly along the X, Y, and/or Z axes, and/or rotationally about the X, Y, and/or Z axes). 
     Display system  12  and optical system  14  of glasses  10  may be configured to display images for a user&#39;s eyes  16  using a lightweight and compact arrangement. In some arrangements, display system  12  may be relatively close to lens system  14 . For example, when glasses  10  are in use, the distance D between display system  12  and lens system  14  may be between 0.5 mm and 1 mm, between 0.1 mm and 0.75 mm, between 0.75 mm and 2 mm, less than 2 mm, greater than 2 mm, or other suitable distance. 
     This type of compact arrangement may raise the risk of impact between display system  12  and lens system  14 . Glasses  10  may be dropped, or an external object may strike glasses  10 . If care is not taken, these types of incidents may cause collisions between lens system  14  and display system  12 , which can cause damage to one or both system. 
     To protect display system  12  and lens system  14 , control circuitry  20  may operate glasses  10  in first and second modes such as an active use mode and a protected mode. When glasses  10  are in active use mode, glasses  10  may operate normally and control circuitry  20  may set distance D to any suitable distance (e.g., may set distance D to a minimum distance, a maximum distance, or any other suitable distance). Control circuitry  20  may, for example, set distance D to a distance that accommodates the user&#39;s eye prescription. 
     When glasses  10  are in protected mode, control circuitry  20  may take certain actions to protect display system  12  and lens system  14 . This may include using actuators  38  to move display system  12  and/or lens system  14  along the Z-axis to increase distance D, using actuators  38  to move display system  12  and/or lens system  14  along the Y-axis to increase the lateral distance between display system  12  and/or lens system  14 , using actuators  38  to rotate display system  12  away from lens system  14  or vice versa, inserting a protective layer between display system  12  and lens system  14  such as a layer of air, fluid, and/or a layer of material that helps prevent collisions between display system  12  and lens system  14 . 
     If desired, control circuitry  20  may take other actions to place glasses  10  in protected mode. For example, control circuitry  20  may provide a protective layer on one or more outer surfaces of glasses  10  to protect glasses  10  from undesired impact. This may include expanding an outer structure (e.g., expanding a face seal or other air-filled structure), deploying a protective layer across the front of glasses  10 , and/or taking other suitable actions. Arrangements in which operating glasses  10  in protected mode includes taking steps to prevent collisions between display system  12  and lens system  14  are sometimes described herein as an illustrative example. 
     Control circuitry  20  may determine when to operate glasses  10  in active use mode and when to operate glasses  10  in protected mode based on sensor data from sensors  24 , based on on/off status information, based on location information, and/or based on other information. For example, control circuitry  20  may use sensors  24 , on/off status information, and/or location information to determine when device  10  is accidentally dropped, to determine when device  10  is not in use, to determine when an incoming external object is likely to strike glasses  10 , and/or to identify other scenarios in which it may be desirable to place glasses  10  in protected mode. 
     As examples, control circuitry  20  may place glasses  10  in protected mode when data from motion sensor  30  indicates that glasses  10  are in freefall, when data from motion sensor  30  and/or an inward-facing camera  28  indicates that glasses  10  have been removed from a user&#39;s head, when data from an outward-facing camera  28  indicates that an external object is nearing contact with glasses  10 , when glasses  10  have been turned off or are otherwise not in use, when location information indicates that glasses  10  are outside, and/or when other information indicates that glasses  10  should be placed in protected mode. 
     Control circuitry  20  may place glasses  10  in active use mode when data from motion sensor  30  indicates that glasses  10  are being lifted off of a surface, when data from motion sensor  30  and/or an inward-facing camera  28  indicates that glasses  10  have been placed on a user&#39;s head, when data from an outward-facing camera  28  indicates that an external object is no longer nearing contact with glasses  10 , when glasses  10  have been turned on or are otherwise in use, when location information indicates that glasses  10  are inside, and/or when other information indicates that glasses  10  should be placed in active use mode. These examples are merely illustrative. In general, control circuitry  20  may place glasses  10  in active use mode or protected mode in response to any suitable information. 
     Control circuitry  20  may control the left and right systems of glasses  10  separately (e.g., such that determining whether to operate the left or right system in active use mode or protected mode is done on a per-eye basis) or control circuitry may control the left and right systems of glasses  10  together (e.g., such that the left and right systems are always operated in the same mode). 
     In some arrangements, glasses  10  may be operated in an active use mode where display system  12  is already sufficiently spaced apart from lens system  14  (e.g., due to a given user&#39;s particular eye prescription). In these scenarios, it may not be necessary for control circuitry  20  to take any action to place glasses  10  in protected mode. 
       FIGS. 3 and 4  show how control circuitry  20  may place glasses  10  in active use mode or protected mode by changing the distance D between lens system  14  and display system  12 . In the active use mode shown in  FIG. 3 , lens system  14  is spaced apart from display system  12  by distance D 1 . In the protected mode of  FIG. 4 , lens system  14  is spaced apart from display system  12  by distance D 2 , which is greater than D 1 . D 1  may be any suitable distance (e.g., a distance based on the user&#39;s eye prescription or other suitable distance). D 1  may, for example, be between 0.5 mm and 1 mm, between 0.1 mm and 0.75 mm, between 0.75 mm and 2 mm, less than 2 mm, greater than 2 mm, or other suitable distance. D 2  may be between 5 mm and 6 mm, between 5 mm and 5.5 mm, between 4 mm and 5 mm, between 2 mm and 3 mm, greater than 3 mm, or less than 3 mm. D 2  may be a maximum distance possible between lens system  14  and display system  12  or may be other suitable distance. 
     Control circuitry  20  may shift from the active mode configuration of  FIG. 3  to the protected mode configuration of  FIG. 4  using actuator  38 . Actuator  38  may be configured to move lens system  14  along the Z-axis (e.g., along an optical axis associated with lens system  14 ) while display system  12  remains fixed, may be configured to move display system  12  along the Z-axis while lens system  14  remains fixed, and/or may be configured to move both lens system  14  and display system  12  along the Z-axis. The actuator that is used to switch between active and protected mode may be the same actuator that controls distance D of  FIG. 1  for accommodating different diopter ranges (e.g., one actuator  38 , sometimes referred to as a focus motor, may be used for eye prescription accommodation and switching between active and protected mode), or the actuator that is used to switch between active and protected mode may be a different actuator from the actuator that controls distance D for accommodating different diopter ranges. 
       FIGS. 5 and 6  show an example in which lens system  14  includes multiple lenses and only one lens is adjusted to switch between active use mode and protected mode. As shown in  FIG. 5 , lens system  14  include first lens  42  and second lens  40 . Second lens  40  (sometimes referred to as interposer lens  40 ) may be interposed between display system  12  and first lens  42 . Control circuitry  20  may place glasses  10  in active use mode or protected mode by changing the position of interposer lens  40 . 
     In the active use mode shown in  FIG. 5 , first lens  42  is spaced apart from interposer lens  40  by distance D 3 , and interposer lens  40  is spaced apart from display system  12  by distance D 4 . In the protected mode of  FIG. 6 , first lens  42  is spaced apart from interposer lens  40  by distance D 5 , and interposer lens  40  is spaced apart from display system  40  by distance D 6 . 
     Control circuitry  20  may shift from the active mode configuration of  FIG. 5  to the protected mode configuration of  FIG. 6  using actuator  38 . Actuator  38  may be configured to move interposer lens  40  along the Z-axis while display system  12  and first lens  42  remain fixed, may be configured to move both lenses  40  and  42  along the Z-axis while display system  12  remains fixed, and/or may be configured to move display system  12  along the Z-axis while both lenses  40  and  42  remain fixed. 
     In arrangements where only interposer lens  40  is moved and display system  12  and first lens  42  are fixed, distance D 6  is greater than distance D 4 , and distance D 5  is less than distance D 3 . In arrangements where both lenses  42  and  40  are moved and display system  12  is fixed, distance D 6  is greater than distance D 4 , and distance D 5  is less than, greater than, or equal to distance D 3 . In arrangements where both lenses  40  and  42  are fixed and display system  12  is moved, distance D 6  is greater than distance D 4 , and distance D 5  is equal to distance D 3 . 
       FIG. 7  shows an example in which control circuitry  20  shifts between active use mode and protected mode by rotating display system  12  relative to lens system  14 . As shown in  FIG. 7 , control circuitry  20  use actuator  38  to shift glasses  10  from active use mode to protected mode by rotating display system  12  about rotational axis  132 . This moves display system  12  in direction  54  from an active use position (where normal axis n is parallel to the Z-axis) to a protected position (indicated with dashed lines), with increased distance between display system  12  and apex  130  of lens system  14 . To place glasses  10  in active use mode, control circuitry  20  may rotate display system  12  back in direction  134  about axis  132 . If desired, display system  12  may rotate about a different axis. Axis  132  of  FIG. 7  is merely illustrative. Arrangements where actuator  38  rotates lens system  14  instead of or in addition to rotating display system  12  may also be used. 
       FIG. 8  shows an example in which control circuitry  20  shifts between active use mode and protected mode by moving lens system  14  laterally relative to display system  12 . As shown in  FIG. 8 , control circuitry  20  use actuator  38  to shift glasses  10  from active use mode to protected mode by shifting lens system  14  in direction  56  (e.g., parallel to the X-axis) to a protected position (indicated with dashed lines). 
     The actuator that is used to switch between active and protected mode of  FIG. 8  may be the same actuator that adjusts the lateral position of lens system  14  for accommodating different interpupillary distances of different users (e.g., one actuator  38 , sometimes referred to as an interpupillary distance motor, may be used for interpupillary distance accommodation and switching between active and protected mode), or the actuator that is used to switch between active and protected mode may be a different actuator from the actuator that accommodates different interpupillary distances. 
     In the example of  FIG. 9 , control circuitry  20  uses fluids to control a distance between display system  12  and lens system  14  to switch between active use mode and protected mode. As shown in  FIG. 9 , glasses  10  may include display system  12  and lens system  14  mounted in housing  32 . Display system  12  may be mounted to a support frame such as support frame  44  that is coupled to a flexible seal  46 . Chamber  58  may be located between display system  12  and lens system  14 . 
     As shown in  FIG. 9 , glasses  10  have has a fluid reservoir such as reservoir  142 . The fluid of reservoir  142  may pass through one or more openings in housing  32  such as opening  48 . Opening  48  may be uncovered or may, if desired, be covered with a permeable layer such as permeable layer  50 . Permeable layer  50  may be an adjustable vent that can be opened and closed (e.g., opened and closed in response to control signals from control circuitry  20 ), or permeable layer  50  may be a porous membrane with numerous openings. 
     Fluid may pass through openings such as opening  48  as indicated by arrow  140  in response to control signals from control circuitry  20 . The fluid may be a gas (e.g., air, nitrogen, etc.) or may be a liquid such as a charged liquid or may be a ferrofluid (e.g., a ferromagnetic material formed from suspended ferromagnetic particles in a liquid carrier). Electrodes for controlling fluid flow may be mounted in any suitable location. When a signal is applied to the electrodes, fluid from layer  142  (e.g., electrically charged liquid in reservoir  142 ) may be drawn into chamber  58 . Lateral barrier structures such as housing  32  may confine the liquid laterally and may cause the liquid to locally push outwards on display system  12  and/or lens system  14 , causing distance D to increase so that glasses  10  are in protected mode. To shift into active mode, control circuitry  20  may draw the fluid out of chamber  58  in direction  52  and back into reservoir  142 , causing distance D to decrease. 
     If desired, the fluid that fills chamber  58  may be air (e.g., from a fan in glasses  10 ) that is pushed through opening  48  into chamber  58 . In this type of scenario, electrodes may not be necessary to control the flow of air through opening  48  into and out of chamber  58 . 
     If desired, control circuitry  20  may deploy a protective layer when glasses  10  are operated in protected mode. This type of arrangement is illustrated in  FIG. 10 . As shown in  FIG. 10 , protective layer  60  may be interposed between display system  12  and lens system  14 . Protective layer  60  may be fixed in the position shown in  FIG. 10 , or protective layer  60  may be moved to a different location when glasses  10  are in active use mode. Protective layer  60  may be layer of polymer, carbon fiber, metal, shape memory material, electroactive polymer, piezoelectric materials, other suitable materials, or a combination of these materials. Protective layer  60  may be actively controlled (e.g., control circuitry  20  may apply control signals to electrodes or other circuitry coupled to protective layer  60  to deploy protective layer  60 ), or protective layer  60  may be passive (e.g., protective layer  60  may automatically be deployed due to gravity when glasses  10  are in freefall, protective layer  60  may be a polymer that becomes stiff under strain, or other passive arrangements may be used). If desired, protective layers in glasses  10  such as protective layer  60  may be deployed in other locations when glasses  10  are in protected mode (e.g., on either side of display system  12 , on either side of lens system  14 , on one or more outer surfaces of glasses  10 , etc.). The example of  FIG. 10  is merely illustrative. 
       FIG. 11  is a flow chart of illustrative steps involved in operating glasses such as glasses  10  of the type shown in  FIGS. 1-10 . 
     At step  100 , control circuitry  20  may gather sensor data from sensors  24  (e.g., ambient light information from ambient light sensor(s)  26 , camera data from camera(s)  28 , motion data from motion sensor(s)  30 , and/or data from other sensors  24 ), location data from communications circuitry (e.g., location data gathered using Global Positioning System Receiver Circuitry, radio-frequency transceiver circuitry, sensors  24 , or other location tracking circuitry), on/off status information (e.g., whether glasses  10  are powered on or off), and/or other information. 
     At step  102 , control circuitry  20  may process the data gathered in step  100  to determine the current state of glasses  10 . Determining the current state of glasses  10  may include determining whether glasses  10  are in use, not in use, vulnerable to an impending collision, or not vulnerable to an impending collision. Step  102  may include, for example, determining whether glasses  10  are in free fall or lifted off of a surface using data from motion sensor  30 , whether glasses  10  have been removed from or placed on a user&#39;s head using data from motion sensor  30  and/or inward-facing camera  28 , whether an external object is nearing contact with or moving away from glasses  10  using outward-facing camera  28 , whether glasses  10  have been turned on or off, whether device  10  is inside or outside, and/or determining other information about the status of glasses  10  based on the information gathered in step  100 . 
     If it is determined in step  102  that glasses  10  are in use and/or that no impending collision is likely, processing may proceed to step  104 . 
     At step  104 , control circuitry  20  may maintain or place glasses  10  in active use mode. If glasses  10  are already in active use mode, no action may be necessary. If glasses  10  are in protected mode, control circuitry  20  may shift glasses  10  from protected mode to active use mode by reducing the distance between display system  12  and lens  14  (e.g., using one or more of the arrangements shown in  FIGS. 3, 5, 7, 8, and 9 ), by retracting or otherwise modifying a protective layer (e.g., protective layer  60  of  FIG. 100 ), and/or by taking other actions to place glasses  10  in a normal use mode. In active use mode, control circuitry  20  may use actuator  38  to adjust the distance between display system  12  and lens  14  based on the user&#39;s eye prescription, if desired. 
     If it is determined in step  102  that glasses  10  are not in use and/or that an impending collision is likely, processing may proceed to step  106 . 
     At step  106 , control circuitry  20  may maintain or place glasses  10  in protected mode. If glasses  10  are already in protected mode, no action may be necessary. If glasses  10  are in active use mode, control circuitry  20  may shift glasses  10  from active use mode to protected mode by increasing the distance between display system  12  and lens  14  (e.g., using one or more of the arrangements shown in  FIGS. 4, 6, 7, 8, and 9 ), by deploying or otherwise modifying a protective layer (e.g., protective layer  60  of  FIG. 10 ), and/or by taking other actions to place glasses  10  in protected mode. 
     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: 20190130
Publication Date: 20211116
Grant Date: 20211116
Priority Date: 20180529
Inventors: FRANKLIN, JEREMY C.
Dey, Stephen E.
HOBSON, Phil M.
LIN, WEY-JIUN
MARIC, IVAN S.
WEBER, ANDREAS G.
Assignee: APPLE INC
CPC Classifications: [{"code": "G02B27/017", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B27/0176", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B27/01", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B7/023", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B2027/0161", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B2027/0163", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B7/021", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B27/646", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B2027/0156", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B7/023", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B27/017", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B27/01", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B7/021", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 63963476