PATENT DOCUMENT

Publication Number: US-11740465-B2
Application Number: US-202117171864-A
Country: US
Kind Code: B2

Title: Optical systems with authentication and privacy capabilities

Abstract:
A head-mounted electronic device may include a display with an optical combiner. The combiner may include a waveguide with first and second output couplers. The first output coupler may couple a first portion of image light at visible wavelengths out of the waveguide and towards an eye box. The second output coupler may couple a second portion of the image light at near-infrared wavelengths out of the waveguide and towards the surrounding environment. The second portion of the image light may include an authentication code that is used by a secondary device to authenticate the head-mounted device and/or may include a pattern that serves to prevent camera equipment in the surrounding environment from capturing accurate facial recognition information from a user while wearing the head-mounted device.

Claims:
What is claimed is: 
     
       1. An electronic device comprising:
 a projector configured to emit first light; 
 a waveguide having a first surface, a second surface opposite the first surface, and an input coupler configured to couple the first light into the waveguide, wherein the waveguide is configured to transmit, from the second surface and through the first surface, second light from an external object; 
 a first output coupler on the waveguide and configured to couple a first portion of the first light out of the waveguide through the first surface; and 
 a second output coupler on the waveguide, wherein the second output coupler is configured to couple a second portion of the first light out of the waveguide through the second surface and the second portion of the first light includes an authentication code for the electronic device. 
 
     
     
       2. The electronic device of  claim 1 , wherein the first portion of the first light comprises light at visible wavelengths and wherein the second portion of the first light comprises light at near-infrared wavelengths. 
     
     
       3. The electronic device of  claim 2 , wherein the second output coupler comprises:
 a filter layer, wherein the filter layer is configured to transmit light at the near-infrared wavelengths and is configured to block light at the visible wavelengths. 
 
     
     
       4. The electronic device of  claim 3 , wherein the first output coupler comprises a set of volume holograms that are Bragg-matched to the visible wavelengths. 
     
     
       5. The electronic device of  claim 3 , wherein the second output coupler further comprises:
 an additional filter layer, wherein the additional filter is configured to block light at the near-infrared wavelengths and is configured to transmit light at the visible wavelengths. 
 
     
     
       6. The electronic device of  claim 2 , wherein the first output coupler comprises a first set of volume holograms that are Bragg-matched to the visible wavelengths and wherein the second output coupler comprises a second set of volume holograms that are Bragg-matched to the near-infrared wavelengths. 
     
     
       7. The electronic device of  claim 1 , wherein the authentication code comprises a two-dimensional authentication code. 
     
     
       8. The electronic device of  claim 7 , wherein the two-dimensional authentication code comprises a plurality of cells, wherein the plurality of cells comprises a first set of cells in which the second portion of the first light is coupled out of the waveguide through the second surface, and wherein the plurality of cells comprises a second set of cells in which none of the first light is coupled out of the waveguide through the second surface. 
     
     
       9. The electronic device of  claim 1 , further comprising:
 one or more processors configured to activate a privacy mode of the electronic device, wherein the projector is configured to, responsive to activation of the privacy mode, produce the second portion of the first light in a pattern that configures the second portion of the first light to obscure capture of images of the waveguide by camera equipment in an environment around the electronic device. 
 
     
     
       10. The electronic device of  claim 1 , wherein the second portion of the first light includes a two-dimensional pseudorandom pattern of cells. 
     
     
       11. An electronic device comprising:
 a waveguide having a first surface and a second surface opposite the first surface, wherein the waveguide is configured to propagate a first portion of light and a second portion of the light via total internal reflection; 
 an input coupler configured to couple the first and second portions of the light into the waveguide; 
 a first output coupler configured to couple the first portion of the light out of the waveguide through the first surface; and 
 a second output coupler configured to couple the second portion of the light out of the waveguide through the second surface, wherein the first portion of the light comprises an image and the second portion of the light comprises a two-dimensional pattern of cells. 
 
     
     
       12. The electronic device of  claim 11 , wherein the two-dimensional pattern of cells comprises a two-dimensional pseudorandom pattern of cells. 
     
     
       13. The electronic device of  claim 11 , wherein the two-dimensional pattern of cells is configured to obscure capture of images of the waveguide by camera equipment in an environment around the electronic device. 
     
     
       14. The electronic device of  claim 11 , wherein the first portion of the light comprises visible wavelengths and wherein the second portion of the light comprises near-infrared wavelengths. 
     
     
       15. The electronic device of  claim 11 , wherein the first output coupler comprises a diffractive grating or a louvered mirror. 
     
     
       16. An electronic device comprising:
 a waveguide having a first surface and a second surface opposite the first surface, wherein the waveguide is configured to propagate a first portion of light and a second portion of the light via total internal reflection; 
 an input coupler configured to couple the first and second portions of the light into the waveguide; 
 a first holographic optical element on the waveguide and configured to couple the first portion of the light out of the waveguide through the first surface; and 
 a second holographic optical element on the waveguide and at least partially overlapping the first holographic optical element, wherein the second holographic optical element is configured to couple the second portion of the light out of the waveguide through the second surface and the second portion of the light is configured to obscure capture of images of the waveguide by camera equipment in an environment around the electronic device. 
 
     
     
       17. The electronic device of  claim 16 , wherein the first portion of the light comprises a first range of wavelengths and wherein the second portion of the light comprises a second range of wavelengths. 
     
     
       18. The electronic device of  claim 17 , wherein the first range of wavelengths comprise a wavelength between 400 nm and 700 nm and wherein the second range of wavelengths comprise a wavelength between 750 nm and 1400 nm.

Description:
This application claims the benefit of U.S. Provisional Application No. 63/000,650, filed Mar. 27, 2020, which is hereby incorporated by reference herein in its entirety. 
    
    
     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. In addition, devices such as augmented reality headsets can present device authentication and privacy challenges for users. 
     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 image light and an optical system that redirects the light from the display unit towards an eye box. The optical system may be an optical combiner that redirects image light from the display module towards the eye box while also passing real-world light within a field of view to the eye box. The optical combiner may include a waveguide, an input coupler that couples the image light into the waveguide, a first output coupler, and a second output coupler. 
     The first output coupler may couple a first portion of the image light (e.g., at visible wavelengths) out of the waveguide and towards the eye box. The first output coupler may include holographic optical elements, louvered mirrors, or other structures. The second output coupler may couple a second portion of the image light (e.g., at near-infrared wavelengths) out of the waveguide and towards the surrounding environment. The second output coupler may be formed from one or more filter layers or from a holographic optical element. 
     The second portion of the image light may include an authentication code that is used by a secondary device to authenticate the head-mounted device. This may allow the secondary device to confirm that an authorized user is using the head-mounted device without requiring all of the user&#39;s facial information or other personal information. The second portion of the image light may additionally or alternatively include a pseudorandom pattern or any other desired pattern that serves to prevent camera equipment in the environment from capturing accurate facial recognition information from the user while wearing the head-mounted device. 
    
    
     
       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 for a display that includes a waveguide, an eye box output coupler, and a world output coupler in accordance with some embodiments. 
         FIG.  3    is a top view of an illustrative waveguide having a world output coupler formed from filter layers in accordance with some embodiments. 
         FIG.  4    is a top view of an illustrative waveguide having a world output coupler and an eye box output coupler formed from holographic optical elements in accordance with some embodiments. 
         FIG.  5    is a diagram of a system in which a secondary device authenticates a head-mounted device and in which an external camera captures facial recognition information in accordance with some embodiments. 
         FIG.  6    is a front view of an illustrative waveguide showing how a world output coupler may be used to display authentication data for a secondary device and/or to prevent an external camera from capturing accurate facial recognition information in accordance with some embodiments. 
         FIG.  7    is a flow chart of illustrative steps that may be performed by a secondary device and a head-mounted device to authenticate the head-mounted device using light displayed by a world output coupler in accordance with some embodiments. 
         FIG.  8    is a flow chart of illustrative steps that may be performed by a head-mounted device to prevent an external camera from capturing accurate facial recognition information 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 display device having one or more displays such as near-eye displays  20  mounted within support structure (housing)  8 . Examples in which system  10  is a head-mounted electronic device (sometimes referred to herein as a head-mounted device, head-mounted display device, or head-mounted display) are described herein as an example. System  10  may therefore sometimes be referred to herein as head-mounted device  10 . This is merely illustrative and, if desired, system  10  may be any desired type of electronic device or optical system. 
     Support structure  8  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  20  on the head or near the eye of a user. Near-eye displays  20  may include one or more display modules such as display modules  20 A and one or more optical systems such as optical systems  20 B. Display modules  20 A may be mounted in a support structure such as support structure  8 . Each display module  20 A may emit light  38  (image light) that is redirected towards a user&#39;s eyes at eye box  24  (as eye box light  38 E) using an associated one of optical systems  20 B. 
     The operation of head-mounted device  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 may be stored on storage in circuitry  16  and run on processing circuitry in circuitry  16  to implement operations for head-mounted device  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.). 
     Head-mounted device  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 head-mounted device  10  from external equipment (e.g., a tethered computer, a portable device such as a handheld device or laptop computer, or other electrical equipment sometimes referred to herein as a secondary electronic device) 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 head-mounted device  10  is operating. Output components in devices  12  may allow head-mounted device  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 head-mounted device  10 , accelerometers, depth sensors, light sensors, haptic output devices, speakers, batteries, wireless communications circuits for communicating between head-mounted device  10  and external electronic equipment, etc.). 
     Display modules  20 A may be liquid crystal displays, organic light-emitting diode displays, laser-based displays, reflective displays, or displays of other types. Optical systems  20 B may form lenses that allow a viewer (e.g., a viewer&#39;s eyes at eye box  24 ) to view images on display(s)  20 . There may be two optical systems  20 B (e.g., for forming left and right lenses) associated with respective left and right eyes of the user. A single display  20  may produce images for both eyes or a pair of displays  20  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 optical system  20 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  20 B may contain components (e.g., an optical combiner, etc.) to allow real-world image light from real-world images or objects  28  to be combined optically with virtual (computer-generated) images such as virtual images in image light  38 . 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 head-mounted device  10  (e.g., in an arrangement where a camera captures real-world images of object  28  and this content is digitally merged with virtual content at optical system  20 B). 
     Head-mounted device  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  20  with image content). During operation, control circuitry  16  may supply image content to display  20 . The content may be remotely received (e.g., from a computer or other content source or secondary device 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  20  by control circuitry  16  may be viewed by a viewer at eye box  24 . 
       FIG.  2    is a top view of an illustrative optical system  20 B that may be used in head-mounted device  10  of  FIG.  1   . As shown in  FIG.  2   , optical system  20 B may include optical elements such as waveguide  50 , input optics  58 , output optics  63 , input coupler  52 , cross coupler  54 , and output coupler  56 . Input optics  58  may include collimating lenses or other optical components that pass image light  38  to input coupler  52 . Image light  38  may be provided to optical system  20 B by a display unit in display module  20 A ( FIG.  1   ). The display unit (sometimes referred to herein as a display engine) may be a display unit based on a liquid crystal display, organic light-emitting diode display, cathode ray tube, plasma display, projector display (e.g., a projector based on an array of micromirrors), liquid crystal on silicon display, or other suitable type of display. Optical system  20 B may be used to present image light  38  output from the display unit to eye box  24 . 
     Waveguide structures such as waveguide  50  in optical system  20 B may be formed from one or more stacked layers of polymer, glass, or other transparent substrates capable of guiding light via total internal reflection. Input coupler  52 , cross coupler  54 , and output coupler  56  may each be partially or completely embedded within waveguide  50  or mounted to a surface of waveguide  50 . Some of optical couplers  52 ,  54 , and  56  may be mounted to a surface of waveguide  50  whereas others of couplers  52 ,  54 , and  56  are embedded within waveguide  50 . One or more of couplers  52 ,  54 , and  56  may be omitted if desired. Output optics  63  may include lenses that help to focus image light  38  coupled out of waveguide  50  by output coupler  56  onto eye box  24 . Input optics  58  and/or output optics  63  may be omitted if desired. 
     Input coupler  52  may be configured to couple image light  38  from the display module into waveguide  50 , whereas output coupler  56  may be configured to couple image light  38  from within waveguide  50  out of waveguide  50  and towards eye box  24  (as eye box light  38 E). For example, when image light  38  from input optics  58  strikes input coupler  52 , input coupler  52  may redirect image light  38  so that the light propagates within waveguide  50  via total internal reflection towards output coupler  56  (e.g., in the direction of the X axis). When light  38  strikes output coupler  56 , output coupler  56  may redirect image light  38  out of waveguide  50  towards eye box  24  (e.g., along the Z axis as eye box light  38 E). 
     In the example of  FIG.  2   , cross coupler  54  is optically interposed between input coupler  52  and output coupler  56 . In this example, input coupler  52  may redirect image light  38  towards cross coupler  54 . Cross coupler  54  may expand image light  38  in a first direction and may also couple (redirect) the expanded light back into waveguide  50 . Waveguide  50  propagates the light expanded by cross coupler  54  via total internal reflection to output coupler  56 . If desired, output coupler  56  may then expand the light received from cross coupler  54  in a second direction that is different from (e.g., perpendicular to) the first direction. Output coupler  56  may, if desired, provide an optical power to the light coupled out of the waveguide. Consider an example in which the image light  38  coupled into waveguide  50  by input coupler  52  includes a pupil of light. Expansion of image light  38  by cross coupler  54  and output coupler  56  may serve to expand the pupil in multiple (e.g., orthogonal) dimensions, thereby allowing a relatively large eye box  24  to be filled with pupils of image light  38  with a sufficient and substantially uniform intensity across the entire area of the eye box. 
     As shown in  FIG.  2   , waveguide  50  may also include an additional output coupler such as output coupler  62 . Output coupler  62  may, for example, partially or completely overlap output coupler  56  on waveguide  50 . Output coupler  56  may couple a first portion of image light  38  out of waveguide  50  and towards eye box  24  as eye box light  38 E (e.g., in a direction towards the face/eye of the user while wearing head-mounted device  10 ). At the same time, output coupler  62  may couple a second portion of image light  38  out of waveguide  50  and towards the exterior world (e.g., a direction opposite to that of eye box light  38 E) as world light  38 W. World light  38 W may be viewable by other people or devices facing head mounted device  10 . Output coupler  56  may therefore sometimes be referred to herein as eye box-facing output coupler  56  or eye box output coupler  56 , whereas output coupler  62  may sometimes be referred to herein as world-facing output coupler  62  or world output coupler  62 . 
     The first portion of image light  38  coupled out of waveguide  50  as eye box light  38 E may be incident upon output couplers  62  and/or  56  at a first range of wavelengths and/or a first range of incident angles whereas the second portion of image light  38  coupled out of waveguide  50  as world light  38 W may be incident upon output couplers  62  and/or  56  at a second range of wavelengths different from the first range of wavelengths and/or a second range of incident angles different from the first range of incident angles. Display module  20 A ( FIG.  1   ) may provide image light  38  to waveguide  50  with a first set of image content (data) to be displayed at eye box  24  as eye box light  38 E (e.g., where the first set of image content is provided by display module  20 A at the first range of wavelengths and/or incident angles). Display module  20 A may concurrently provide image light  38  to waveguide  50  with a second set of image content (data) to be displayed to the exterior world as world light  38 W (e.g., where the second set of image content is provided by display module  20 A at the second range of wavelengths and/or incident angles). The same display module may be used to provide the first and second sets of image content or different display modules may be used to provide the first and second sets of image content respectively. Control circuitry  16  ( FIG.  1   ) may control display  20 A to provide image light  38  to waveguide  50  in this way. 
     Input coupler  52 , cross coupler  54 , eye box output coupler  56 , and/or world output coupler  62  may be based on reflective and refractive optics, may be based on filter layers (e.g., dichroic filters, low-pass filters, high-pass filters, etc.), or may be based on holographic (e.g., diffractive) optics. Combinations of these arrangements may be used across the couplers if desired. In arrangements where couplers  52 ,  54 ,  56 , or  62  are formed from reflective and refractive optics, the couplers may include one or more reflectors (e.g., an array of micromirrors, partial mirrors, louvered mirrors, louvered partial reflectors, or other reflectors). In arrangements where couplers  52 ,  54 ,  56 , or  62  are based on holographic optics, the couplers may include holographic media such as photopolymers, gelatin such as dichromated gelatin, silver halides, holographic polymer dispersed liquid crystal, or other suitable volume holographic media. Holographic recordings (e.g., holographic phase gratings sometimes referred to herein as holograms) may be stored in the holographic media. The holographic media may sometimes be referred to herein as grating media. 
     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 grating medium if desired. The holographic phase gratings may be, for example, volume holograms in the grating medium. 
     If desired, one or more of couplers  52 ,  54 ,  56 , and  62  may be implemented using other types of diffraction grating structures such as surface relief grating structures. Surface relief grating structures include diffraction gratings (e.g., surface relief gratings) that are mechanically cut, etched, or otherwise formed in a surface relief grating medium. The surface relief gratings diffract light that is incident upon the surface relief gratings. Rather than modulating index of refraction in the grating medium (as performed to create holographic phase gratings such as volume holograms), surface relief gratings are produced by varying the physical thickness of the medium across its lateral area. Multiple surface relief gratings (e.g., two surface relief gratings) may be multiplexed within the same volume of surface relief grating medium if desired. Meta-gratings may be used in another suitable arrangement. 
     In one suitable arrangement that is sometimes described herein as an example, input coupler  52  is a non-diffractive input coupler (e.g., an input coupler that does not include diffraction gratings such as surface relief gratings or holographic phase gratings). For example, input coupler  52  may include an input prism (e.g., a transmissive or reflective prism), an angled surface (edge) of waveguide  50 , etc. Use of a non-diffractive input coupler such as an input prism may allow image light  38  to be coupled into waveguide  50  without producing the chromatic dispersion that is otherwise associated with input-coupling using diffractive elements. In another suitable arrangement, input coupler  52  may be formed using diffraction gratings such as volume holograms or other grating structures. In these scenarios, any chromatic dispersion introduced by the input coupler may be reversed by the output coupler in diffracting the light out of the waveguide (e.g., in a scenario where the output coupler includes holographic phase gratings such as volume holograms). 
     Cross coupler  54  may include diffractive grating structures that diffract the image light  38  coupled into waveguide  50  by the (non-diffractive) input coupler  52 . The grating structures in cross coupler  54  may include surface relief grating structures (e.g., one or more surface relief gratings) or phase grating structures such as volume holographic grating structures (e.g., a set of at least partially overlapping volume holograms). In another suitable arrangement, cross coupler  54  may include reflective structures such as louvered mirrors. 
     In the example of  FIG.  2   , waveguide  50  is an optical combiner that combines real-world light  60  (sometimes referred to herein as environmental light  60  or world light  60 ) with eye box light  38 E from display module  20 A (e.g., for an augmented reality display system). In this scenario, eye box output coupler  56  may provide eye box light  38 E to eye box  24  for view by the user of head-mounted device  10  while wearing head-mounted device  10 . Eye box light  38 E may include both at least a portion of the image light  38  that propagates down waveguide  50  via total internal reflection (e.g., the first portion of the image light coupled out of waveguide  50  by eye box output coupler  56 ) and environmental light  60  from external real-world objects  28  (e.g., eye box light  38 E may superimpose digitally-generated image data with light from a real world scene in front of head-mounted device  10 ). 
     At the same time, head-mounted device  10  may use world light  38 W coupled out of waveguide  50  by world output coupler  62  to convey (e.g., display) information or other data/content to the real world external to the user and head-mounted device  10 . This information may be observed by other people in the vicinity of head-mounted device  10  (e.g., people other than the user wearing head-mounted device  10 ) and/or by other external equipment being used to capture images of head-mounted device  10  and/or the user of head-mounted device  10 . In addition, some light such as light  64  may pass from the face and/or eye of the user of device  10  to the exterior world through waveguide  50 . This light  64  may, for example, include ambient light or other light that has reflected off of the user&#39;s eye and/or face while the user is wearing head-mounted device  10 . Light  64  may therefore sometimes be referred to herein as facial light  64 . As with world light  38 W, facial light  64  may be observed by other people in the vicinity of head-mounted device  10  and/or by other external equipment being used to capture images of head-mounted device  10  and/or the user of head-mounted device  10 . 
       FIG.  3    is a top view of waveguide  50  showing how world output coupler  62  of  FIG.  2    may be formed using filter layers on waveguide  50 . As shown in  FIG.  3   , waveguide  50  may include a substrate layer  76  (e.g., a layer of grating medium, a glass layer, a plastic layer, etc.). Substrate layer  76  (waveguide  50 ) may have a first lateral surface  74  and an opposing second lateral surface  72 . Lateral surface  74  faces eye box  24  and the user&#39;s face while the user wears head-mounted device  10 . Lateral surface  72  faces the real world external to the user&#39;s face (e.g., faces away from eye box  24  and the user while the user wears head-mounted device  10 ). 
     A first filter layer such as filter layer  70  may be layered onto lateral surface  72  of substrate layer  76 . A second filter layer such as filter layer  73  may be layered onto lateral surface  74  of waveguide  50  (e.g., filter layers  70  and  73  may form world output coupler  62  of  FIG.  2   ). Filter layers  70  and  73  may completely or at least partially overlap (e.g., in the X-Y plane). Filter layer  70  may block or reflect light of the first range of wavelengths (e.g., light to be directed towards eye box  24  as eye box light  38 E) while transmitting light of the second range of wavelengths (e.g., light to be directed towards the external world as world light  38 W). Similarly, filter layer  73  may transmit light of the first range of wavelengths (e.g., light to be directed towards eye box  24  as eye box light  38 E) while blocking or reflecting light of the second range of wavelengths (e.g., light to be directed towards the external world as world light  38 W). 
     In general, the first and second ranges of wavelengths may include any desired wavelengths. In one suitable arrangement that is sometimes described herein as an example, the first range of wavelengths includes visible wavelengths (e.g., any desired set of wavelengths from about 400 nm to about 700 nm) whereas the second range of wavelengths includes near-infrared (NIR) wavelengths (e.g., any desired set of wavelengths from about 750 nm to about 1400 nm). Display module  20 A ( FIG.  1   ) may produce image light  38  that includes first image content at the first range of wavelengths (e.g., visible wavelengths) to be displayed at eye box  24  as eye box light  38 E and that includes second image content at the second range of wavelengths (e.g., NIR wavelengths) to be displayed to the external world as world light  38 W. Using near-infrared wavelengths for world light  38 W may prevent world light  38 W from undesirably obscuring the view of environmental light  60  ( FIG.  2   ) to the user at eye box  24 , for example. 
     In this arrangement, filter layer  70  may be a long-pass filter configured to transmit light of the second range of wavelengths (e.g., NIR wavelengths) while blocking light of the first range of wavelengths (e.g., visible wavelengths). Filter layer  73  may be a short-pass filter configured to transmit light of the first range of wavelengths while blocking light of the second range of wavelengths. When image light  38  (e.g., light that includes both the first and second ranges of wavelengths) reaches filter layer  70 , filter layer  70  may filter out light of the second range of wavelengths as world light  38 W, which is then transmitted to the exterior world. Light at the first range of wavelengths (e.g., eye box light  38 E) may reflect off of surface  72  towards eye box output coupler  56 . Eye box output coupler  56  couples eye box light  38 E out of waveguide  50  and towards eye box  24 . Filter layer  73  may transmit eye box light  38 E. Any remaining world light  38 W that is reflected off of surface  72  may be blocked by filter layer  73  from passing to eye box  24 , as shown by arrow  75 . 
     The example of  FIG.  3    is merely illustrative. Filter layers  70  and  73  may include any desired filter elements (e.g., dichroic filters, filters having pass bands, filters having stop bands, etc.). Filter layer  73  may be omitted if desired. In another suitable arrangement, eye box output coupler  56  and world output coupler  62  of  FIG.  2    may be formed using holographic optical elements on waveguide  50 .  FIG.  4    is a top view of waveguide  50  showing how world output coupler  62  and eye box output coupler  56  of  FIG.  2    may be formed using holographic optical elements in waveguide  50 . 
     As shown in  FIG.  4   , waveguide  50  may include substrate layers  80  and  82  (e.g., glass layers, layers of grating medium, plastic layers, etc.). Substrate layer  82  faces eye box  24  whereas substrate layer  80  faces the exterior world. Waveguide  50  may include a first holographic optical element  86  and a second holographic optical element  84 . Holographic optical elements  86  and  84  may completely or at least partially overlap in waveguide  50  (e.g., in the X-Y plane). Holographic optical element  86  may include a first set of diffractive gratings (e.g., holograms such as volume holograms). The first set of diffractive gratings may include multiple multiplexed gratings that diffract different respective subsets of the first range of wavelengths and/or incident angles associated with eye box light  38 E. Holographic optical element  84  may include a second set of diffractive gratings (e.g., holograms such as volume holograms). The second set of diffractive gratings may include multiple multiplexed gratings that diffract different respective subsets of the second range of wavelengths and/or incident angles associated with world light  38 W. The diffractive gratings in holographic optical element  84  and the diffractive gratings in holographic optical element  86  may be recorded in respective grating medium layers of waveguide  50 . In another suitable arrangement, the diffractive gratings in holographic optical element  84  may be recorded (e.g., superimposed) in the same volume of grating medium as the diffractive gratings in holographic optical element  86 . One or more additional substrate layers and/or layers of optically clear adhesive may be interposed between holographic optical elements  84  and  86  if desired. Substrate layers  80  and/or  82  may be omitted if desired. 
     Holographic optical element  84  may form world output coupler  62  whereas holographic optical element  86  forms eye box output coupler  56  of  FIG.  2   . The diffractive gratings in holographic optical element  86  may be configured to diffract the eye box light  38 E in the image light  38  provided by display module  20 A out of waveguide  50  and towards eye box  24  (e.g., the diffractive gratings in holographic optical element  86  may be Bragg-matched to the first range of wavelengths and/or incident angles associated with eye box light  38 E such that eye box light  38 E is diffracted onto output angles that direct eye box light  38 E towards eye box  24 ). The diffractive gratings in holographic optical element  84  may be configured to diffract the world light  38 W in the image light  38  provided by display module  20 A out of waveguide  50  and towards the exterior world (e.g., the diffractive gratings in holographic optical element  84  may be Bragg-matched to the second range of wavelengths and/or incident angles associated with world light  38 W such that world light  38 W is diffracted onto output angles that direct world light  38 W towards the exterior world). In this example, holographic optical element  84  includes transmissive gratings whereas holographic optical element  86  includes reflective gratings. This is merely illustrative. Holographic optical element  84  may include reflective gratings and/or holographic optical element  86  may include transmissive gratings if desired). 
     Facial recognition has become a common method for mobile authentication to ensure that a particular user is authorized to operate a particular electronic device. In addition, facial recognition is becoming a more common method of user tracking for personal data agglomeration. For example, retail stores may implement facial recognition technology to identify shoppers and then either use that information to provide targeted shopping experiences or to then sell that information to other entities. Many users would prefer to control with whom they share private data such as their shopping preferences. 
     Head-mounted device  10  may use world light  38 W to display information and/or other signals to the exterior world. If desired, head-mounted device  10  may use world light  38 W to display authentication information that is used to authenticate head-mounted device  10  for a corresponding user. If desired, head-mounted device  10  may additionally or alternatively use world light  38 W to shield the user from facial recognition technologies. 
       FIG.  5    is a diagram of a system in which head-mounted device  10  may be operated. As shown in  FIG.  5   , system  104  may include head-mounted device  10  and external equipment such as secondary (electronic) device  100 . Secondary device  100  may include control circuitry such as control circuitry  16  of  FIG.  1    and sensors and other components such as sensors and other components  18  of  FIG.  1   . Secondary device  100  may, for example, be a cellular telephone, a tablet computer, a laptop computer, a desktop computer, a display (computer) monitor, a display monitor having an embedded computer therein, a wearable device such as a wristwatch, pendant, or head-mounted device, a gaming controller, a remote control, a home entertainment system, a media console, a portable speaker, a wireless access point or base station, a gaming system, a portable media player, a vehicle, an electronic kiosk, or any other desired electronic equipment. 
     Secondary device  100  may have wireless communications circuitry and image sensor circuitry. The image sensor circuitry may capture images of visible light as well as light at other wavelengths such as NIR light. The wireless communications circuitry may include a wireless transceiver, baseband processor, and one or more antennas for supporting wireless links such as cellular telephone links, wireless local area network links, wireless personal area network links (e.g., Bluetooth® links), or other links. There may be multiple users within system  104  such as users  106  and  108 . User  106  may, for example, be an authorized user of head-mounted device  10  whereas user  108  is not authorized to use head-mounted device  10 . When a given user puts head-mounted device  10  on their head, secondary device  100  may perform authentication operations to ensure that that user is authorized to use head-mounted device  10  before certain functions of head-mounted device  10  are enabled. 
     For example, secondary device  100  may use wireless communication circuitry to provide an authentication code to head-mounted device  10  over wireless link  110  (e.g., a wireless local area network link, a wireless personal area network link, etc.). Display module  20 A on head-mounted device  10  ( FIG.  1   ) may produce world light  38 W that includes the authentication code. World output coupler  62  ( FIG.  2   ) may display the authentication code in world light  38 W to the exterior world. Secondary device  100  may capture image data (e.g., NIR image data) of the authentication code in world light  38 W. Secondary device  100  may also capture other facial recognition image data from light  112  reflected off of the user while the user wears head-mounted device  10 . Light  112  may include facial light  64  ( FIG.  2   ) and/or, if desired, may include light reflected off of portions of the user&#39;s face that are not covered by head-mounted device  10 . Secondary device  100  may process the facial recognition image data and the image data captured from the authentication code to verify that the user wearing head-mounted device  10  is authorized to use head-mounted device  10 . 
     If the user is authorized (e.g., if user  106  is wearing head-mounted device  10 ), secondary device  100  may enable certain features of head-mounted device  10  that are only available to authorized users (e.g., via link  110 ). For example, secondary device  100  may enable head-mounted device  10  to begin displaying augmented reality content in eye box light  38 E, may allow head-mounted device  10  to be powered on, may allow the user to make purchases using head-mounted device  10 , may allow the user to access their personal accounts or data using head-mounted device  10 , etc. If the user is not authorized (e.g., if user  108  is wearing head-mounted device  10 ), secondary device  100  may not enable these features or may actively disable features of head-mounted device  10 . This may provide additional hardware authentication for head-mounted device  10  and may, for example, be used to replace other facial recognition-based authentication procedures for secondary device  100  so the user does not need to provide their facial information to send and/or receive personalized information using head-mounted device  10 . 
     In some scenarios, a user wearing head-mounted device  10  may enter a surveilled area or region  111 . Region  111  may be a region in which camera equipment such as camera  102  is used to gather facial recognition data from persons. Region  111  may be, for example, a retail store, public space, airport, transportation hub, public transport vehicle, educational campus, government facility, etc. Cameras such as camera  102  in region  111  may gather facial recognition data at one or more wavelengths such as NIR wavelengths. 
     Some users may wish to prevent cameras such as camera  102  from capturing images of their face for facial recognition purposes (e.g., to prevent undesired transmission of their personal data to other parties). Display module  20 A on head-mounted device  10  ( FIG.  1   ) may produce world light  38 W that includes a two-dimensional pattern of information that serves to obscure camera  102  from capturing accurate images of the user&#39;s eyes for use in facial recognition operations. The pattern may be a random or pseudo-random pattern or any other desired pattern of light that interferes with the ability of camera  102  to capture accurate facial recognition data from the user&#39;s eyes or face. The wavelength of world light  38 W may be selected to overlap with the wavelengths with which camera  102  captures images (e.g., the absorption band of camera  102  such as a band that includes NIR wavelengths). This mode may also be used for authentication purposes if head-mounted device  10  also incorporates a retinal scanning and/or proximity sensor, if desired. Head-mounted device  10  may perform these operations to help shield the user&#39;s privacy from facial recognition technologies when the user and head-mounted device  10  are located within region  111 . These operations may be disabled or deactivated when head-mounted device  10  is not located within region  111  if desired. 
       FIG.  6    is a front view showing how world output coupler  62  may display world light  38 W for authentication and/or privacy purposes. As shown in  FIG.  6   , the lateral edges (e.g., rim) of waveguide  50  may be mounted to support structures  8  (e.g., a frame running around the periphery of waveguide  50 ). The example of  FIG.  6    is merely illustrative. Support structures and waveguide  50  may have any desired lateral shape. 
     The user&#39;s eye  122  may overlap waveguide  50  (e.g., at eye box  24  of  FIGS.  1 - 4   ). World output coupler  62  on waveguide  50  may overlap eye  122 . Eye box output coupler  56  ( FIG.  2   ) is not shown in  FIG.  6    for the sake of clarity but may direct eye box light  38 E ( FIG.  2   ) towards eye  122  (e.g., in the +Z direction). World output coupler  62  may couple world light  38 W out of waveguide  50  and towards the exterior world (e.g., in the −Z direction). As shown in  FIG.  6   , world light  38 W may include a two-dimensional pattern (code) of cells (pixels)  120 . The pattern may be produced by display module  20 A of  FIG.  1   , for example. In the example of  FIG.  6   , the two-dimensional pattern of cells  120  is a binary code in which some cells have a logic “1” value (e.g., shaded cells  120 A) whereas other cells have a logic “0” value (e.g., unshaded cells  120 B). Shaded cells  120 A may correspond to regions of world output coupler  62  that are provided with world light  38 W by display module  20 A whereas unshaded cells  120 B may correspond to regions of world output coupler  62  that do not receive world light  38 W from display module  20 A (e.g., NIR light may be directed towards the exterior world within shaded cells  120 A but not within unshaded cells  120 B of world light  38 W). This example is merely illustrative. If desired, the pattern of cells  120  may be greyscale-encoded (e.g., with more than two possible logical values for each cell  120 ). 
     In performing authentication operations, secondary device  100  of  FIG.  5    may provide the particular pattern (code) to be displayed using world light  38 W. Head-mounted device  10  may then display that pattern to the exterior world using world light  38 W and world output coupler  62 . An image sensor on secondary device  100  may capture an image (e.g., an NIR image) of the displayed pattern and may process the encoded cells  120  of the displayed pattern to authenticate head-mounted device  10 . If desired, the image sensor or another image sensor on secondary device  100  may also capture other image data (e.g., visible light image data) from eye  122  (e.g., through waveguide  50 ) or from other portions of the user&#39;s face that are overlapped by waveguide  50  or that are not overlapped by head-mounted device  10  and may use this image data in conjunction with the image of the displayed pattern to authenticate device  10  (e.g., to ensure that the user having eye  122  is authorized to use that particular head-mounted device  10 ). 
     In shielding the user&#39;s privacy from facial recognition technology, display module  20 A may produce world light  38 W that includes a random or pseudorandom pattern of cells  120  to help obscure the details of eye  122  and/or other portions of the user&#39;s face overlapping waveguide  50  from being accurately captured by camera  102  of  FIG.  5    (e.g., at NIR wavelengths). If desired, world light  38 W may be displayed with NIR light filling all cells  120  (e.g., all cells  120  in world light  38 W may be shaded cells  120 A) to help mask the user&#39;s eye from view by camera  102 . Because world light  38 W is provided at non-visible wavelengths (e.g., NIR wavelengths or other infrared wavelengths), world light  38 W remains invisible to eye  122  and to other people who are looking at the user. This may allow head-mounted device  10  to appear to the naked eye as if no additional information is being displayed to the exterior world by waveguide  50 , thereby optimizing the aesthetics of head-mounted device  10  and allowing for unobstructed eye contact between the user and other people, even though world output coupler  62  may be concurrently displaying world light  38 W that is otherwise visible to secondary device  100  and/or camera  102  ( FIG.  5   ) for authentication or privacy purposes. The example of  FIG.  6    is merely illustrative. World light  38 W may include a one-dimensional pattern (e.g., a barcode type pattern) or any other desired pattern or coding. 
       FIG.  7    is a flow chart of illustrative steps that may be performed by head-mounted device  10  and secondary device  100  in authenticating head-mounted device  10  for a corresponding user. Steps  130  of  FIG.  7    (e.g., steps  134 ,  136 ,  138 ,  140 ,  146 , and  148 ) of  FIG.  7    may be performed by secondary device  100 . Steps  132  of  FIG.  7    (e.g., steps  150 ,  152 ,  154 , and  148 ) may be performed by head-mounted device  10 . The steps of  FIG.  7    may be performed after a user has picked up head-mounted device  10 , placed head-mounted device  10  over their eyes, attempted to perform actions using head-mounted device  10  that would require user authentication (e.g., attempted to access private information, attempted to make a purchase, attempted to use log in credentials, etc.), or otherwise attempted to use or activate head-mounted device  10 , as examples. Secondary device  100  may use sensors to determine when the user has attempted to activate or use head-mounted device  10  in a manner that requires authentication and/or secondary device  100  may receive signals from head-mounted device  10  (e.g., over link  110  of  FIG.  5   ) identifying that the user has attempted to activate or use head-mounted device  10  in a manner that requires authentication. 
     At step  130 , secondary device  100  may transmit an authentication request to head-mounted device  10 . Secondary device  100  may transmit the authentication request using radio-frequency signals (e.g., using link  110  of  FIG.  5   ), using optical signals, or using any other desired means. The authentication request may identify an authentication pattern or code to be displayed by head-mounted device  10 . 
     At step  150 , head-mounted device  10  may receive the authentication request transmitted by secondary device  100 . Display module  20 A may generate image light  38  that includes world light  38 W and may provide image light  38  to waveguide  50 . The world light  38 W in image light  38  may include the authentication pattern or code identified by the received authentication request. 
     At step  152 , world output coupler  62  may couple world light  38 W out of waveguide  50  and towards the exterior world (e.g., towards secondary device  100 ). World light  38 W may include cells  120  ( FIG.  6   ) that display the authentication pattern or code (e.g., in a two-dimensional array of cells  120  that are displayed in different logical states such as shown by cells  120 A and  120 B of  FIG.  6   , thereby encoding the authentication pattern or code). 
     At step  136 , secondary device  100  may use one or more image sensors to capture image data from the authentication code displayed in world light  38 W from head-mounted device  10  (e.g., as coupled out of waveguide  50  by world output coupler  62 ). The image data may include NIR or IR image data (e.g., in scenarios where world light  38 W is displayed by head-mounted device  10  at NIR or IR wavelengths). 
     At optional step  138 , secondary device  100  may capture other facial image data from the user of head-mounted device  10 . The facial image data may be captured at visible, NIR, IR, and/or other wavelengths. The facial image data may be captured in response to light received by secondary device  100  through waveguide  50  (e.g., light reflected off of the user&#39;s eyes or other portions of the user&#39;s face overlapping head-mounted device  10  such as facial light  64  of  FIG.  2   ) and/or light received by secondary device  100  from portions of the user&#39;s face that are not overlapped by head-mounted device  10 . 
     At step  140 , control circuitry on secondary device  100  may process the image data captured from the authentication code displayed in world light  38 W and optionally the other facial image data (e.g., as captured at step  138 ) to authenticate the user of head-mounted device  10 . For example, secondary device  100  may authenticate the user if the image data captured from the authentication code displayed in world light  38 W includes the authentication pattern or code identified by the authentication request transmitted at step  134  (e.g., secondary device  100  may then have confidence that the head-mounted device  10  that displayed the pattern is the expected head-mounted device  10  subject to the authentication request) and/or if the other facial image data matches expected or predetermined facial image data associated with an authorized user of that head-mounted device  10 . This is merely illustrative and, in general, any desired authentication algorithm may be used to authenticate the user for that particular head-mounted device  10  using the displayed pattern and optionally the other facial image data. 
     If secondary device  100  is unable to authenticate the user for head-mounted device  10  (e.g., if the other facial recognition image data does not match an authorized user, if the other facial recognition image data does not match head-mounted device  10 , and/or if the head-mounted device does not display the correct authentication code as identified by the authentication request, etc.), processing may loop back to step  134  as shown by path  142 . Other operations may also be performed in response to a failure in authentication, such as powering down head-mounted device  10 , blocking access to features of head-mounted device  10  until authentication can be performed, etc. 
     If secondary device  100  successfully authenticates the user to head-mounted device  10 , processing may proceed to step  146  as shown by path  144 . At step  146 , secondary device  100  may transmit an authentication confirmation to head-mounted device  10 . 
     At step  154 , head-mounted device  10  may receive the authentication confirmation from secondary device  100 . The authentication confirmation may confirm to head-mounted device  10  that the user wearing head-mounted device  10  is an authorized user. 
     At step  148 , head-mounted device  10  and/or secondary device  100  may perform user-authenticated operations. The user-authenticated operations may include any desired operations that require authentication of the user of head-mounted device  10 . Such operations may include, for example, allowing head-mounted device  10  to power on, beginning to display eye box light  38 E to the user, allowing the user to access personal or private data using head-mounted device  10 , allowing the user to make purchases using head-mounted device  10 , allowing the user to use their log in credentials using head-mounted device  10 , enabling certain applications or operations on head-mounted device  10 , etc. The user-authenticated operations may continue until a trigger condition occurs. The trigger condition may include, for example, the user removing head-mounted device  10  from their head, head-mounted device  10  being powered off, the passage of a predetermined amount of time, entry of head-mounted device  10  into a particular geographic area or region, or any other desired trigger condition for which authentication may need to be performed again. 
     The steps of  FIG.  7    are merely illustrative. Two or more of the steps of  FIG.  7    may be performed at least partially concurrently. The steps of  FIG.  7    may be performed in other orders. Head-mounted device  10  may display eye box light  38 E ( FIGS.  2 - 4   ) to eye box  24  (e.g., to provide augmented reality content to the user) concurrently with one, more than one, or all of the steps of  FIG.  7    (e.g., head-mounted device  10  may continue to perform augmented reality operations even while displaying world light  38 W). 
       FIG.  8    is a flow chart of illustrative steps that may be performed by head-mounted device  10  in preventing external cameras from gathering accurate facial recognition information from the user of head-mounted device  10 . 
     At step  170 , head-mounted device  10  may activate a privacy mode. Head-mounted device  10  may activate the privacy mode in response to an input provided by the user of head-mounted device  10  (e.g., using an input/output device of head-mounted device  10 , via an input/output device of secondary device  100 , etc.) or may activate the privacy mode autonomously (e.g., in response to detecting the presence of camera  102  of  FIG.  6   , in response to detecting that head-mounted device  10  has entered region  111 , in response to the operation or call of one or more applications running on head-mounted device  10  and/or secondary device  100 , etc.). Prior to activating the privacy mode, head-mounted device  10  may not display world light  38 W (e.g., all cells  120  of  FIG.  6    may be unshaded cells  120 B) or may be displaying world light  38 W for purposes other than protecting the privacy of the user from facial recognition technologies (e.g., to authenticate device  10  as shown in  FIG.  7   ). 
     At step  172 , head-mounted device  10  may display world light  38 W to obscure the user&#39;s eyes from facial recognition data-gathering external equipment such as camera  102  of  FIG.  5   . For example, world output coupler  62  may display world light  38 W in all cells of the world light (e.g., all cells  120  of  FIG.  6    may be shaded cells  120 A) or may display world light  38 W in a random, pseudorandom, or other pattern. This may serve to prevent camera  102  from capturing accurate facial recognition image data of the user&#39;s eyes while wearing head-mounted device  10  (e.g., at the wavelengths of world light  38 W such as NIR wavelengths). By preventing camera  102  from capturing accurate facial recognition image data, head-mounted device  10  may also prevent camera  102  from tracking the user&#39;s personal information (e.g., the user&#39;s shopping preferences, etc.), because camera  102  will be unable to associate the user with a particular user profile. 
     At step  174 , head-mounted device  10  may deactivate the privacy mode. Head-mounted device  10  may deactivate the privacy mode in response to an input provided by the user of head-mounted device  10  (e.g., using an input/output device of head-mounted device  10 , via an input/output device of secondary device  100 , etc.) or may deactivate the privacy mode autonomously (e.g., in response to detecting that head-mounted device  10  has left region  111  of  FIG.  6   , in response to the operation or call of one or more applications running on head-mounted device  10  and/or secondary device  100 , etc.). After deactivating the privacy mode, head-mounted device  10  may not display world light  38 W (e.g., all cells  120  of  FIG.  6    may be unshaded cells  120 B) or may be displaying world light  38 W for purposes other than protecting the privacy of the user from facial recognition technologies. Head-mounted device  10  may display eye box light  38 E ( FIGS.  2 - 4   ) to eye box  24  (e.g., to provide augmented reality content to the user) concurrently with one, more than one, or all of the steps of  FIG.  8    (e.g., head-mounted device  10  may continue to perform augmented reality operations even while displaying world light  38 W). 
     As described above, one aspect of the present technology is the gathering and use of data available from various sources to improve the delivery of images to users, to authenticate particular users and devices, to shield user privacy, to perform facial recognition operations, and/or to perform other display-related operations. The present disclosure contemplates that in some instances, this gathered data may include personal information data that uniquely identifies or can be used to contact or locate a specific person. Such personal information data can include facial recognition data, demographic data, location-based data, telephone numbers, email addresses, twitter ID&#39;s, home addresses, data or records relating to a user&#39;s health or level of fitness (e.g., vital signs measurements, medication information, exercise information), date of birth, or any other identifying or personal information. 
     The present disclosure recognizes that the use of such personal information data, in the present technology, can be used to the benefit of users. For example, the personal information data can be used to authenticate a user before enabling certain device operations, to update displayed images, and/or to perform other desired display operations. Accordingly, use of such personal information data enables users to view updated display images and to access secure content and functionality that are only accessible to authenticated users. Further, other uses for personal information data that benefit the user are also contemplated by the present disclosure. For instance, health and fitness data may be used to provide insights into a user&#39;s general wellness, or may be used as positive feedback to individuals using technology to pursue wellness goals. 
     The present disclosure contemplates that the entities responsible for the collection, analysis, disclosure, transfer, storage, or other use of such personal information data will comply with well-established privacy policies and/or privacy practices. In particular, such entities should implement and consistently use privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining personal information data private and secure. Such policies should be easily accessible by users, and should be updated as the collection and/or use of data changes. Personal information from users should be collected for legitimate and reasonable uses of the entity and not shared or sold outside of those legitimate uses. Further, such collection/sharing should occur after receiving the informed consent of the users. Additionally, such entities should consider taking any needed steps for safeguarding and securing access to such personal information data and ensuring that others with access to the personal information data adhere to their privacy policies and procedures. Further, such entities can subject themselves to evaluation by third parties to certify their adherence to widely accepted privacy policies and practices. In addition, policies and practices should be adapted for the particular types of personal information data being collected and/or accessed and adapted to applicable laws and standards, including jurisdiction-specific considerations. For instance, in the US, collection of or access to certain health data may be governed by federal and/or state laws, such as the Health Insurance Portability and Accountability Act (HIPAA); whereas health data in other countries may be subject to other regulations and policies and should be handled accordingly. Hence different privacy practices should be maintained for different personal data types in each country. 
     Despite the foregoing, the present disclosure also contemplates embodiments in which users selectively block the use of, or access to, personal information data. That is, the present disclosure contemplates that hardware and/or software elements can be provided to prevent or block access to such personal information data. For example, in the case of user authentication, the present technology can be configured to allow users to select to “opt in” or “opt out” of participation in the collection of personal information data during registration for services or anytime thereafter (e.g., the user may still use other means of authenticating themselves for a particular head-mounted device, such as by entering a password, providing a fingerprint, or using other credentials). In another example, users can select not to perform facial recognition based authentication or other operations that gather personal information data. In yet another example, users can select to limit the length of time facial recognition and authentication is performed. In addition to providing “opt in” and “opt out” options, the present disclosure contemplates providing notifications relating to the access or use of personal information. For instance, a user may be notified upon downloading an app that their personal information data will be accessed and then reminded again just before personal information data is accessed by the app. 
     Moreover, it is the intent of the present disclosure that personal information data should be managed and handled in a way to minimize risks of unintentional or unauthorized access or use. Risk can be minimized by limiting the collection of data and deleting data once it is no longer needed. In addition, and when applicable, including in certain health related applications, data de-identification can be used to protect a user&#39;s privacy. De-identification may be facilitated, when appropriate, by removing specific identifiers (e.g., date of birth, etc.), controlling the amount or specificity of data stored (e.g., collecting location data a city level rather than at an address level), controlling how data is stored (e.g., aggregating data across users), and/or other methods. 
     Therefore, although the present disclosure broadly covers use of personal information data to implement one or more various disclosed embodiments, the present disclosure also contemplates that the various embodiments can also be implemented without the need for accessing such personal information data. That is, the various embodiments of the present technology are not rendered inoperable due to the lack of all or a portion of such personal information data. For example, head-mounted device  10  may display images or perform authentication based on non-personal information data or a bare minimum amount of personal information, such as the content being requested by the device associated with a user, other non-personal information available to the display system, or publicly available information. 
     A physical environment refers to a physical world that people can sense and/or interact with without aid of electronic systems. Physical environments, such as a physical park, include physical articles, such as physical trees, physical buildings, and physical people. People can directly sense and/or interact with the physical environment, such as through sight, touch, hearing, taste, and smell. 
     In contrast, a computer-generated reality (CGR) environment refers to a wholly or partially simulated environment that people sense and/or interact with via an electronic system (e.g., an electronic system including the display systems described herein). In CGR, a subset of a person&#39;s physical motions, or representations thereof, are tracked, and, in response, one or more characteristics of one or more virtual objects simulated in the CGR environment are adjusted in a manner that comports with at least one law of physics. For example, a CGR system may detect a person&#39;s head turning and, in response, adjust graphical content and an acoustic field presented to the person in a manner similar to how such views and sounds would change in a physical environment. In some situations (e.g., for accessibility reasons), adjustments to characteristic(s) of virtual object(s) in a CGR environment may be made in response to representations of physical motions (e.g., vocal commands). 
     A person may sense and/or interact with a CGR object using any one of their senses, including sight, sound, touch, taste, and smell. For example, a person may sense and/or interact with audio objects that create 3D or spatial audio environment that provides the perception of point audio sources in 3D space. In another example, audio objects may enable audio transparency, which selectively incorporates ambient sounds from the physical environment with or without computer-generated audio. In some CGR environments, a person may sense and/or interact only with audio objects. Examples of CGR include virtual reality and mixed reality. 
     A virtual reality (VR) environment refers to a simulated environment that is designed to be based entirely on computer-generated sensory inputs for one or more senses. A VR environment comprises a plurality of virtual objects with which a person may sense and/or interact. For example, computer-generated imagery of trees, buildings, and avatars representing people are examples of virtual objects. A person may sense and/or interact with virtual objects in the YR environment through a simulation of the person&#39;s presence within the computer-generated environment, and/or through a simulation of a subset of the person&#39;s physical movements within the computer-generated environment. 
     In contrast to a VR environment, which is designed to be based entirely on computer-generated sensory inputs, a mixed reality (MR) environment refers to a simulated environment that is designed to incorporate sensory inputs from the physical environment, or a representation thereof, in addition to including computer-generated sensory inputs (e.g., virtual objects). On a virtuality continuum, a mixed reality environment is anywhere between, but not including, a wholly physical environment at one end and virtual reality environment at the other end. 
     In some MR environments, computer-generated sensory inputs may respond to changes in sensory inputs from the physical environment. Also, some electronic systems for presenting an MR environment may track location and/or orientation with respect to the physical environment to enable virtual objects to interact with real objects (that is, physical articles from the physical environment or representations thereof). For example, a system may account for movements so that a virtual tree appears stationery with respect to the physical ground. Examples of mixed realities include augmented reality and augmented virtuality. 
     An augmented reality (AR) environment refers to a simulated environment n which one or more virtual objects are superimposed over a physical environment, or a representation thereof. For example, an electronic system for presenting an AR environment may have a transparent or translucent display through which a person may directly view the physical environment. The system may be configured to present virtual objects on the transparent or translucent display, so that a person, using the system, perceives the virtual objects superimposed over the physical environment. Alternatively, a system may have an opaque display and one or more imaging sensors that capture images or video of the physical environment, which are representations of the physical environment. The system composites the images or video with virtual objects, and presents the composition on the opaque display. A person, using the system, indirectly views the physical environment by way of the images or video of the physical environment, and perceives the virtual objects superimposed over the physical environment. As used herein, a video of the physical environment shown on an opaque display is called “pass-through video,” meaning a system uses one or more image sensor(s) to capture images of the physical environment, and uses those images in presenting the AR environment on the opaque display. Further alternatively, a system may have a projection system that projects virtual objects into the physical environment, for example, as a hologram or on a physical surface, so that a person, using the system, perceives the virtual objects superimposed over the physical environment. 
     An augmented reality environment also refers to a simulated environment in which a representation of a physical environment is transformed by computer-generated sensory information. For example, in providing pass-through video, a system may transform one or more sensor images to impose a select perspective (e.g., viewpoint) different than the perspective captured by the imaging sensors. As another example, a representation of a physical environment may be transformed by graphically modifying (e.g., enlarging) portions thereof, such that the modified portion may be representative but not photorealistic versions of the originally captured images. As a further example, a representation of a physical environment may be transformed by graphically eliminating or obfuscating portions thereof. 
     An augmented virtuality (AV) environment refers to a simulated environment in which a virtual or computer generated environment incorporates one or more sensory inputs from the physical environment. The sensory inputs may be representations of one or more characteristics of the physical environment. For example, an AV park may have virtual trees and virtual buildings, but people with faces photorealistically reproduced from images taken of physical people. As another example, a virtual object may adopt a shape or color of a physical article imaged by one or more imaging sensors. As a further example, a virtual object may adopt shadows consistent with the position of the sun in the physical environment. 
     There are many different types of electronic systems that enable a person to sense and/or interact with various CGR environments. Examples include head mounted systems, projection-based systems, heads-up displays (HUDs), vehicle windshields having integrated display capability, windows having integrated display capability, displays formed as lenses designed to be placed on a person&#39;s eyes (e.g., similar to contact lenses), headphones/earphones, speaker arrays, input systems (e.g., wearable or handheld controllers with or without haptic feedback), smartphones, tablets, and desktop/laptop computers. A head mounted system may have one or more speaker(s) and an integrated opaque display. Alternatively, a head mounted system may be configured to accept an external opaque display (e.g., a smartphone). The head mounted system may incorporate one or more imaging sensors to capture images or video of the physical environment, and/or one or more microphones to capture audio of the physical environment. Rather than an opaque display, a head mounted system may have a transparent or translucent display. The transparent or translucent display may have a medium through which light representative of images is directed to a person&#39;s eyes. The display may utilize digital light projection, OLEDs, LEDs, uLEDs, liquid crystal on silicon, laser scanning light source, or any combination of these technologies. The medium may be an optical waveguide, a hologram medium, an optical combiner, an optical reflector, or any combination thereof. In one embodiment, the transparent or translucent display may be configured to become opaque selectively. Projection-based systems may employ retinal projection technology that projects graphical images onto a person&#39;s retina. Projection systems also may be configured to project virtual objects into the physical environment, for example, as a hologram or on a physical surface. The display systems described herein may be used for these types of systems and for any other desired display arrangements. 
     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: 20210209
Publication Date: 20230829
Grant Date: 20230829
Priority Date: 20200327
Inventors: DODSON, CHRISTOPHER M.
PFEIFFER, JONATHAN B.
Assignee: APPLE INC
CPC Classifications: [{"code": "H04N23/21", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B27/0172", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B6/0036", "inventive": true, "first": false, "tree": "[]"}, {"code": "G03H1/0248", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06V10/143", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06V20/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06V20/20", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06V40/172", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N5/33", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B2027/014", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B2027/0138", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B2027/0174", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B27/0172", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B27/0172", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B2027/0174", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06V40/172", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06V20/20", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06V10/143", "inventive": true, "first": false, "tree": "[]"}, {"code": "G03H1/0248", "inventive": false, "first": false, "tree": "[]"}, {"code": "G03H2001/2615", "inventive": false, "first": false, "tree": "[]"}, {"code": "G03H2001/266", "inventive": false, "first": false, "tree": "[]"}, {"code": "G03H1/0248", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B2027/0138", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04N5/33", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B2027/0174", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B2027/014", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B6/0036", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06V20/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06V10/143", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06V20/20", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06V40/172", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 77856334