Patent Description:
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'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. <CIT> discloses a head-mounted display system configured to project light to an eye of a user wearing the head-mounted display system to display content in a vision field of said user. In particular, the document teaches a beam of light which is redirected by an optical element.

The invention is defined by appended independent claim <NUM>. 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's surrounding environment.

The near-eye display includes 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 is 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 is configured to 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 is configured to 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'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.

An illustrative system having a device with one or more near-eye display systems is shown in <FIG>. System <NUM> may be a head-mounted display device having one or more displays such as near-eye displays <NUM> mounted within support structure (housing) <NUM>. Examples in which system <NUM> 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 <NUM> may therefore sometimes be referred to herein as head-mounted device <NUM>. This is merely illustrative and, if desired, system <NUM> may be any desired type of electronic device or optical system.

Support structure <NUM> 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 <NUM> on the head or near the eye of a user. Near-eye displays <NUM> may include one or more display modules such as display modules 20A and one or more optical systems such as optical systems 20B. Display modules 20A may be mounted in a support structure such as support structure <NUM>. Each display module 20A may emit light <NUM> (image light) that is redirected towards a user's eyes at eye box <NUM> (as eye box light 38E) using an associated one of optical systems 20B.

The operation of head-mounted device <NUM> may be controlled using control circuitry <NUM>. Control circuitry <NUM> may include storage and processing circuitry for controlling the operation of system <NUM>. Circuitry <NUM> 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 <NUM> 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 <NUM> and run on processing circuitry in circuitry <NUM> to implement operations for head-mounted device <NUM> (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 <NUM> may include input-output circuitry such as input-output devices <NUM>. Input-output devices <NUM> may be used to allow data to be received by head-mounted device <NUM> 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 <NUM> with user input. Input-output devices <NUM> may also be used to gather information on the environment in which head-mounted device <NUM> is operating. Output components in devices <NUM> may allow head-mounted device <NUM> to provide a user with output and may be used to communicate with external electrical equipment. Input-output devices <NUM> may include sensors and other components <NUM> (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 <NUM>, accelerometers, depth sensors, light sensors, haptic output devices, speakers, batteries, wireless communications circuits for communicating between head-mounted device <NUM> and external electronic equipment, etc.).

Display modules 20A may be liquid crystal displays, organic light-emitting diode displays, laser-based displays, reflective displays, or displays of other types. Optical systems 20B may form lenses that allow a viewer (e.g., a viewer's eyes at eye box <NUM>) to view images on display(s) <NUM>. There may be two optical systems 20B (e.g., for forming left and right lenses) associated with respective left and right eyes of the user. A single display <NUM> may produce images for both eyes or a pair of displays <NUM> 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 20B 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 20B may contain components (e.g., an optical combiner, etc.) to allow real-world image light from real-world images or objects <NUM> to be combined optically with virtual (computer-generated) images such as virtual images in image light <NUM>. In this type of system, which is sometimes referred to as an augmented reality system, a user of system <NUM> 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 <NUM> (e.g., in an arrangement where a camera captures real-world images of object <NUM> and this content is digitally merged with virtual content at optical system 20B).

Head-mounted device <NUM> 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 <NUM> with image content). During operation, control circuitry <NUM> may supply image content to display <NUM>. The content may be remotely received (e.g., from a computer or other content source or secondary device coupled to system <NUM>) and/or may be generated by control circuitry <NUM> (e.g., text, other computer-generated content, etc.). The content that is supplied to display <NUM> by control circuitry <NUM> may be viewed by a viewer at eye box <NUM>.

<FIG> is a top view of an illustrative optical system 20B that may be used in head-mounted device <NUM> of <FIG>. As shown in <FIG>, optical system 20B may include optical elements such as waveguide <NUM>, input optics <NUM>, output optics <NUM>, input coupler <NUM>, cross coupler <NUM>, and output coupler <NUM>. Input optics <NUM> may include collimating lenses or other optical components that pass image light <NUM> to input coupler <NUM>. Image light <NUM> may be provided to optical system 20B by a display unit in display module 20A (<FIG>). 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 20B may be used to present image light <NUM> output from the display unit to eye box <NUM>.

Waveguide structures such as waveguide <NUM> in optical system 20B 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 <NUM>, cross coupler <NUM>, and output coupler <NUM> may each be partially or completely embedded within waveguide <NUM> or mounted to a surface of waveguide <NUM>. Some of optical couplers <NUM>, <NUM>, and <NUM> may be mounted to a surface of waveguide <NUM> whereas others of couplers <NUM>, <NUM>, and <NUM> are embedded within waveguide <NUM>. One or more of couplers <NUM>, <NUM>, and <NUM> may be omitted if desired. Output optics <NUM> may include lenses that help to focus image light <NUM> coupled out of waveguide <NUM> by output coupler <NUM> onto eye box <NUM>. Input optics <NUM> and/or output optics <NUM> may be omitted if desired.

Input coupler <NUM> may be configured to couple image light <NUM> from the display module into waveguide <NUM>, whereas output coupler <NUM> may be configured to couple image light <NUM> from within waveguide <NUM> out of waveguide <NUM> and towards eye box <NUM> (as eye box light 38E). For example, when image light <NUM> from input optics <NUM> strikes input coupler <NUM>, input coupler <NUM> may redirect image light <NUM> so that the light propagates within waveguide <NUM> via total internal reflection towards output coupler <NUM> (e.g., in the direction of the X axis). When light <NUM> strikes output coupler <NUM>, output coupler <NUM> may redirect image light <NUM> out of waveguide <NUM> towards eye box <NUM> (e.g., along the Z axis as eye box light 38E).

In the example of <FIG>, cross coupler <NUM> is optically interposed between input coupler <NUM> and output coupler <NUM>. In this example, input coupler <NUM> may redirect image light <NUM> towards cross coupler <NUM>. Cross coupler <NUM> may expand image light <NUM> in a first direction and may also couple (redirect) the expanded light back into waveguide <NUM>. Waveguide <NUM> propagates the light expanded by cross coupler <NUM> via total internal reflection to output coupler <NUM>. If desired, output coupler <NUM> may then expand the light received from cross coupler <NUM> in a second direction that is different from (e.g., perpendicular to) the first direction. Output coupler <NUM> may, if desired, provide an optical power to the light coupled out of the waveguide. Consider an example in which the image light <NUM> coupled into waveguide <NUM> by input coupler <NUM> includes a pupil of light. Expansion of image light <NUM> by cross coupler <NUM> and output coupler <NUM> may serve to expand the pupil in multiple (e.g., orthogonal) dimensions, thereby allowing a relatively large eye box <NUM> to be filled with pupils of image light <NUM> with a sufficient and substantially uniform intensity across the entire area of the eye box.

As shown in <FIG>, waveguide <NUM> may also include an additional output coupler such as output coupler <NUM>. Output coupler <NUM> may, for example, partially or completely overlap output coupler <NUM> on waveguide <NUM>. Output coupler <NUM> may couple a first portion of image light <NUM> out of waveguide <NUM> and towards eye box <NUM> as eye box light 38E (e.g., in a direction towards the face/eye of the user while wearing head-mounted device <NUM>). At the same time, output coupler <NUM> may couple a second portion of image light <NUM> out of waveguide <NUM> and towards the exterior world (e.g., a direction opposite to that of eye box light 38E) as world light 38W. World light 38W may be viewable by other people or devices facing head mounted device <NUM>. Output coupler <NUM> may therefore sometimes be referred to herein as eye box-facing output coupler <NUM> or eye box output coupler <NUM>, whereas output coupler <NUM> may sometimes be referred to herein as world-facing output coupler <NUM> or world output coupler <NUM>.

The first portion of image light <NUM> coupled out of waveguide <NUM> as eye box light 38E may be incident upon output couplers <NUM> and/or <NUM> at a first range of wavelengths and/or a first range of incident angles whereas the second portion of image light <NUM> coupled out of waveguide <NUM> as world light 38W may be incident upon output couplers <NUM> and/or <NUM> 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 20A (<FIG>) may provide image light <NUM> to waveguide <NUM> with a first set of image content (data) to be displayed at eye box <NUM> as eye box light 38E (e.g., where the first set of image content is provided by display module 20A at the first range of wavelengths and/or incident angles). Display module 20A may concurrently provide image light <NUM> to waveguide <NUM> with a second set of image content (data) to be displayed to the exterior world as world light 38W (e.g., where the second set of image content is provided by display module 20A 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 <NUM> (<FIG>) may control display 20A to provide image light <NUM> to waveguide <NUM> in this way.

Input coupler <NUM>, cross coupler <NUM>, eye box output coupler <NUM>, and/or world output coupler <NUM> 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 <NUM>, <NUM>, <NUM>, or <NUM> 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 <NUM>, <NUM>, <NUM>, or <NUM> 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 <NUM>, <NUM>, <NUM>, and <NUM> 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 <NUM> 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 <NUM> may include an input prism (e.g., a transmissive or reflective prism), an angled surface (edge) of waveguide <NUM>, etc. Use of a non-diffractive input coupler such as an input prism may allow image light <NUM> to be coupled into waveguide <NUM> without producing the chromatic dispersion that is otherwise associated with input-coupling using diffractive elements. In another suitable arrangement, input coupler <NUM> 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 <NUM> may include diffractive grating structures that diffract the image light <NUM> coupled into waveguide <NUM> by the (non-diffractive) input coupler <NUM>. The grating structures in cross coupler <NUM> 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 <NUM> may include reflective structures such as louvered mirrors.

In the example of <FIG>, waveguide <NUM> is an optical combiner that combines real-world light <NUM> (sometimes referred to herein as environmental light <NUM> or world light <NUM>) with eye box light 38E from display module 20A (e.g., for an augmented reality display system). In this scenario, eye box output coupler <NUM> may provide eye box light 38E to eye box <NUM> for view by the user of head-mounted device <NUM> while wearing head-mounted device <NUM>. Eye box light 38E may include both at least a portion of the image light <NUM> that propagates down waveguide <NUM> via total internal reflection (e.g., the first portion of the image light coupled out of waveguide <NUM> by eye box output coupler <NUM>) and environmental light <NUM> from external real-world objects <NUM> (e.g., eye box light 38E may superimpose digitally-generated image data with light from a real world scene in front of head-mounted device <NUM>).

At the same time, head-mounted device <NUM> may use world light 38W coupled out of waveguide <NUM> by world output coupler <NUM> to convey (e.g., display) information or other data/content to the real world external to the user and head-mounted device <NUM>. This information may be observed by other people in the vicinity of head-mounted device <NUM> (e.g., people other than the user wearing head-mounted device <NUM>) and/or by other external equipment being used to capture images of head-mounted device <NUM> and/or the user of head-mounted device <NUM>. In addition, some light such as light <NUM> may pass from the face and/or eye of the user of device <NUM> to the exterior world through waveguide <NUM>. This light <NUM> may, for example, include ambient light or other light that has reflected off of the user's eye and/or face while the user is wearing head-mounted device <NUM>. Light <NUM> may therefore sometimes be referred to herein as facial light <NUM>. As with world light 38W, facial light <NUM> may be observed by other people in the vicinity of head-mounted device <NUM> and/or by other external equipment being used to capture images of head-mounted device <NUM> and/or the user of head-mounted device <NUM>.

<FIG> is a top view of waveguide <NUM> showing how world output coupler <NUM> of <FIG> may be formed using filter layers on waveguide <NUM>. As shown in <FIG>, waveguide <NUM> may include a substrate layer <NUM> (e.g., a layer of grating medium, a glass layer, a plastic layer, etc.). Substrate layer <NUM> (waveguide <NUM>) may have a first lateral surface <NUM> and an opposing second lateral surface <NUM>. Lateral surface <NUM> faces eye box <NUM> and the user's face while the user wears head-mounted device <NUM>. Lateral surface <NUM> faces the real world external to the user's face (e.g., faces away from eye box <NUM> and the user while the user wears head-mounted device <NUM>).

A first filter layer such as filter layer <NUM> may be layered onto lateral surface <NUM> of substrate layer <NUM>. A second filter layer such as filter layer <NUM> may be layered onto lateral surface <NUM> of waveguide <NUM> (e.g., filter layers <NUM> and <NUM> may form world output coupler <NUM> of <FIG>). Filter layers <NUM> and <NUM> may completely or at least partially overlap (e.g., in the X-Y plane). Filter layer <NUM> may block or reflect light of the first range of wavelengths (e.g., light to be directed towards eye box <NUM> as eye box light 38E) while transmitting light of the second range of wavelengths (e.g., light to be directed towards the external world as world light 38W). Similarly, filter layer <NUM> may transmit light of the first range of wavelengths (e.g., light to be directed towards eye box <NUM> as eye box light 38E) while blocking or reflecting light of the second range of wavelengths (e.g., light to be directed towards the external world as world light 38W).

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 <NUM> to about <NUM>) whereas the second range of wavelengths includes near-infrared (NIR) wavelengths (e.g., any desired set of wavelengths from about <NUM> to about <NUM>). Display module 20A (<FIG>) may produce image light <NUM> that includes first image content at the first range of wavelengths (e.g., visible wavelengths) to be displayed at eye box <NUM> as eye box light 38E 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 38W. Using near-infrared wavelengths for world light 38W may prevent world light 38W from undesirably obscuring the view of environmental light <NUM> (<FIG>) to the user at eye box <NUM>, for example.

In this arrangement, filter layer <NUM> 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 <NUM> 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 <NUM> (e.g., light that includes both the first and second ranges of wavelengths) reaches filter layer <NUM>, filter layer <NUM> may filter out light of the second range of wavelengths as world light 38W, which is then transmitted to the exterior world. Light at the first range of wavelengths (e.g., eye box light 38E) may reflect off of surface <NUM> towards eye box output coupler <NUM>. Eye box output coupler <NUM> couples eye box light 38E out of waveguide <NUM> and towards eye box <NUM>. Filter layer <NUM> may transmit eye box light 38E. Any remaining world light 38W that is reflected off of surface <NUM> may be blocked by filter layer <NUM> from passing to eye box <NUM>, as shown by arrow <NUM>.

The example of <FIG> is merely illustrative. Filter layers <NUM> and <NUM> may include any desired filter elements (e.g., dichroic filters, filters having pass bands, filters having stop bands, etc.). Filter layer <NUM> may be omitted if desired. In another suitable arrangement, eye box output coupler <NUM> and world output coupler <NUM> of <FIG> may be formed using holographic optical elements on waveguide <NUM>. <FIG> is a top view of waveguide <NUM> showing how world output coupler <NUM> and eye box output coupler <NUM> of <FIG> may be formed using holographic optical elements in waveguide <NUM>.

As shown in <FIG>, waveguide <NUM> may include substrate layers <NUM> and <NUM> (e.g., glass layers, layers of grating medium, plastic layers, etc.). Substrate layer <NUM> faces eye box <NUM> whereas substrate layer <NUM> faces the exterior world. Waveguide <NUM> may include a first holographic optical element <NUM> and a second holographic optical element <NUM>. Holographic optical elements <NUM> and <NUM> may completely or at least partially overlap in waveguide <NUM> (e.g., in the X-Y plane). Holographic optical element <NUM> 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 38E. Holographic optical element <NUM> 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 38W. The diffractive gratings in holographic optical element <NUM> and the diffractive gratings in holographic optical element <NUM> may be recorded in respective grating medium layers of waveguide <NUM>. In another suitable arrangement, the diffractive gratings in holographic optical element <NUM> may be recorded (e.g., superimposed) in the same volume of grating medium as the diffractive gratings in holographic optical element <NUM>. One or more additional substrate layers and/or layers of optically clear adhesive may be interposed between holographic optical elements <NUM> and <NUM> if desired. Substrate layers <NUM> and/or <NUM> may be omitted if desired.

Holographic optical element <NUM> may form world output coupler <NUM> whereas holographic optical element <NUM> forms eye box output coupler <NUM> of <FIG>. The diffractive gratings in holographic optical element <NUM> may be configured to diffract the eye box light 38E in the image light <NUM> provided by display module 20A out of waveguide <NUM> and towards eye box <NUM> (e.g., the diffractive gratings in holographic optical element <NUM> may be Bragg-matched to the first range of wavelengths and/or incident angles associated with eye box light 38E such that eye box light 38E is diffracted onto output angles that direct eye box light 38E towards eye box <NUM>). The diffractive gratings in holographic optical element <NUM> may be configured to diffract the world light 38W in the image light <NUM> provided by display module 20A out of waveguide <NUM> and towards the exterior world (e.g., the diffractive gratings in holographic optical element <NUM> may be Bragg-matched to the second range of wavelengths and/or incident angles associated with world light 38W such that world light 38W is diffracted onto output angles that direct world light 38W towards the exterior world). In this example, holographic optical element <NUM> includes transmissive gratings whereas holographic optical element <NUM> includes reflective gratings. This is merely illustrative. Holographic optical element <NUM> may include reflective gratings and/or holographic optical element <NUM> 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 <NUM> may use world light 38W to display information and/or other signals to the exterior world. If desired, head-mounted device <NUM> may use world light 38W to display authentication information that is used to authenticate head-mounted device <NUM> for a corresponding user. If desired, head-mounted device <NUM> may additionally or alternatively use world light 38W to shield the user from facial recognition technologies.

<FIG> is a diagram of a system in which head-mounted device <NUM> may be operated. As shown in <FIG>, system <NUM> may include head-mounted device <NUM> and external equipment such as secondary (electronic) device <NUM>. Secondary device <NUM> may include control circuitry such as control circuitry <NUM> of <FIG> and sensors and other components such as sensors and other components <NUM> of <FIG>. Secondary device <NUM> 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 <NUM> 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 <NUM> such as users <NUM> and <NUM>. User <NUM> may, for example, be an authorized user of head-mounted device <NUM> whereas user <NUM> is not authorized to use head-mounted device <NUM>. When a given user puts head-mounted device <NUM> on their head, secondary device <NUM> may perform authentication operations to ensure that that user is authorized to use head-mounted device <NUM> before certain functions of head-mounted device <NUM> are enabled.

For example, secondary device <NUM> may use wireless communication circuitry to provide an authentication code to head-mounted device <NUM> over wireless link <NUM> (e.g., a wireless local area network link, a wireless personal area network link, etc.). Display module 20A on head-mounted device <NUM> (<FIG>) may produce world light 38W that includes the authentication code. World output coupler <NUM> (<FIG>) may display the authentication code in world light 38W to the exterior world. Secondary device <NUM> may capture image data (e.g., NIR image data) of the authentication code in world light 38W. Secondary device <NUM> may also capture other facial recognition image data from light <NUM> reflected off of the user while the user wears head-mounted device <NUM>. Light <NUM> may include facial light <NUM> (<FIG>) and/or, if desired, may include light reflected off of portions of the user's face that are not covered by head-mounted device <NUM>. Secondary device <NUM> 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 <NUM> is authorized to use head-mounted device <NUM>.

If the user is authorized (e.g., if user <NUM> is wearing head-mounted device <NUM>), secondary device <NUM> may enable certain features of head-mounted device <NUM> that are only available to authorized users (e.g., via link <NUM>). For example, secondary device <NUM> may enable head-mounted device <NUM> to begin displaying augmented reality content in eye box light 38E, may allow head-mounted device <NUM> to be powered on, may allow the user to make purchases using head-mounted device <NUM>, may allow the user to access their personal accounts or data using head-mounted device <NUM>, etc. If the user is not authorized (e.g., if user <NUM> is wearing head-mounted device <NUM>), secondary device <NUM> may not enable these features or may actively disable features of head-mounted device <NUM>. This may provide additional hardware authentication for head-mounted device <NUM> and may, for example, be used to replace other facial recognition-based authentication procedures for secondary device <NUM> so the user does not need to provide their facial information to send and/or receive personalized information using head-mounted device <NUM>.

In some scenarios, a user wearing head-mounted device <NUM> may enter a surveilled area or region <NUM>. Region <NUM> may be a region in which camera equipment such as camera <NUM> is used to gather facial recognition data from persons. Region <NUM> may be, for example, a retail store, public space, airport, transportation hub, public transport vehicle, educational campus, government facility, etc. Cameras such as camera <NUM> in region <NUM> may gather facial recognition data at one or more wavelengths such as NIR wavelengths.

Some users may wish to prevent cameras such as camera <NUM> 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 20A on head-mounted device <NUM> (<FIG>) may produce world light 38W that includes a two-dimensional pattern of information that serves to obscure camera <NUM> from capturing accurate images of the user'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 <NUM> to capture accurate facial recognition data from the user's eyes or face. The wavelength of world light 38W may be selected to overlap with the wavelengths with which camera <NUM> captures images (e.g., the absorption band of camera <NUM> such as a band that includes NIR wavelengths). This mode may also be used for authentication purposes if head-mounted device <NUM> also incorporates a retinal scanning and/or proximity sensor, if desired. Head-mounted device <NUM> may perform these operations to help shield the user's privacy from facial recognition technologies when the user and head-mounted device <NUM> are located within region <NUM>. These operations may be disabled or deactivated when head-mounted device <NUM> is not located within region <NUM> if desired.

<FIG> is a front view showing how world output coupler <NUM> may display world light 38W for authentication and/or privacy purposes. As shown in <FIG>, the lateral edges (e.g., rim) of waveguide <NUM> may be mounted to support structures <NUM> (e.g., a frame running around the periphery of waveguide <NUM>). The example of <FIG> is merely illustrative. Support structures and waveguide <NUM> may have any desired lateral shape.

The user's eye <NUM> may overlap waveguide <NUM> (e.g., at eye box <NUM> of <FIG>). World output coupler <NUM> on waveguide <NUM> may overlap eye <NUM>. Eye box output coupler <NUM> (<FIG>) is not shown in <FIG> for the sake of clarity but may direct eye box light 38E (<FIG>) towards eye <NUM> (e.g., in the +Z direction). World output coupler <NUM> may couple world light 38W out of waveguide <NUM> and towards the exterior world (e.g., in the -Z direction). As shown in <FIG>, world light 38W may include a two-dimensional pattern (code) of cells (pixels) <NUM>. The pattern may be produced by display module 20A of <FIG>, for example. In the example of <FIG>, the two-dimensional pattern of cells <NUM> is a binary code in which some cells have a logic "<NUM>" value (e.g., shaded cells 120A) whereas other cells have a logic "<NUM>" value (e.g., unshaded cells 120B). Shaded cells 120A may correspond to regions of world output coupler <NUM> that are provided with world light 38W by display module 20A whereas unshaded cells 120B may correspond to regions of world output coupler <NUM> that do not receive world light 38W from display module 20A (e.g., NIR light may be directed towards the exterior world within shaded cells 120A but not within unshaded cells 120B of world light 38W). This example is merely illustrative. If desired, the pattern of cells <NUM> may be greyscale-encoded (e.g., with more than two possible logical values for each cell <NUM>).

In performing authentication operations, secondary device <NUM> of <FIG> may provide the particular pattern (code) to be displayed using world light 38W. Head-mounted device <NUM> may then display that pattern to the exterior world using world light 38W and world output coupler <NUM>. An image sensor on secondary device <NUM> may capture an image (e.g., an NIR image) of the displayed pattern and may process the encoded cells <NUM> of the displayed pattern to authenticate head-mounted device <NUM>. If desired, the image sensor or another image sensor on secondary device <NUM> may also capture other image data (e.g., visible light image data) from eye <NUM> (e.g., through waveguide <NUM>) or from other portions of the user's face that are overlapped by waveguide <NUM> or that are not overlapped by head-mounted device <NUM> and may use this image data in conjunction with the image of the displayed pattern to authenticate device <NUM> (e.g., to ensure that the user having eye <NUM> is authorized to use that particular head-mounted device <NUM>).

In shielding the user's privacy from facial recognition technology, display module 20A may produce world light 38W that includes a random or pseudorandom pattern of cells <NUM> to help obscure the details of eye <NUM> and/or other portions of the user's face overlapping waveguide <NUM> from being accurately captured by camera <NUM> of <FIG> (e.g., at NIR wavelengths). If desired, world light 38W may be displayed with NIR light filling all cells <NUM> (e.g., all cells <NUM> in world light 38W may be shaded cells 120A) to help mask the user's eye from view by camera <NUM>. Because world light 38W is provided at non-visible wavelengths (e.g., NIR wavelengths or other infrared wavelengths), world light 38W remains invisible to eye <NUM> and to other people who are looking at the user. This may allow head-mounted device <NUM> to appear to the naked eye as if no additional information is being displayed to the exterior world by waveguide <NUM>, thereby optimizing the aesthetics of head-mounted device <NUM> and allowing for unobstructed eye contact between the user and other people, even though world output coupler <NUM> may be concurrently displaying world light 38W that is otherwise visible to secondary device <NUM> and/or camera <NUM> (<FIG>) for authentication or privacy purposes. The example of <FIG> is merely illustrative. World light 38W may include a one-dimensional pattern (e.g., a barcode type pattern) or any other desired pattern or coding.

<FIG> is a flow chart of illustrative steps that may be performed by head-mounted device <NUM> and secondary device <NUM> in authenticating head-mounted device <NUM> for a corresponding user. Steps <NUM> of <FIG> (e.g., steps <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>) of <FIG> may be performed by secondary device <NUM>. Steps <NUM> of <FIG> (e.g., steps <NUM>, <NUM>, <NUM>, and <NUM>) may be performed by head-mounted device <NUM>. The steps of <FIG> may be performed after a user has picked up head-mounted device <NUM>, placed head-mounted device <NUM> over their eyes, attempted to perform actions using head-mounted device <NUM> 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 <NUM>, as examples. Secondary device <NUM> may use sensors to determine when the user has attempted to activate or use head-mounted device <NUM> in a manner that requires authentication and/or secondary device <NUM> may receive signals from head-mounted device <NUM> (e.g., over link <NUM> of <FIG>) identifying that the user has attempted to activate or use head-mounted device <NUM> in a manner that requires authentication.

At step <NUM>, secondary device <NUM> may transmit an authentication request to head-mounted device <NUM>. Secondary device <NUM> may transmit the authentication request using radio-frequency signals (e.g., using link <NUM> of <FIG>), 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 <NUM>.

At step <NUM>, head-mounted device <NUM> may receive the authentication request transmitted by secondary device <NUM>. Display module 20A may generate image light <NUM> that includes world light 38W and may provide image light <NUM> to waveguide <NUM>. The world light 38W in image light <NUM> may include the authentication pattern or code identified by the received authentication request.

At step <NUM>, world output coupler <NUM> may couple world light 38W out of waveguide <NUM> and towards the exterior world (e.g., towards secondary device <NUM>). World light 38W may include cells <NUM> (<FIG>) that display the authentication pattern or code (e.g., in a two-dimensional array of cells <NUM> that are displayed in different logical states such as shown by cells 120A and 120B of <FIG>, thereby encoding the authentication pattern or code).

At step <NUM>, secondary device <NUM> may use one or more image sensors to capture image data from the authentication code displayed in world light 38W from head-mounted device <NUM> (e.g., as coupled out of waveguide <NUM> by world output coupler <NUM>). The image data may include NIR or IR image data (e.g., in scenarios where world light 38W is displayed by head-mounted device <NUM> at NIR or IR wavelengths).

At optional step <NUM>, secondary device <NUM> may capture other facial image data from the user of head-mounted device <NUM>. 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 <NUM> through waveguide <NUM> (e.g., light reflected off of the user's eyes or other portions of the user's face overlapping head-mounted device <NUM> such as facial light <NUM> of <FIG>) and/or light received by secondary device <NUM> from portions of the user's face that are not overlapped by head-mounted device <NUM>.

At step <NUM>, control circuitry on secondary device <NUM> may process the image data captured from the authentication code displayed in world light 38W and optionally the other facial image data (e.g., as captured at step <NUM>) to authenticate the user of head-mounted device <NUM>. For example, secondary device <NUM> may authenticate the user if the image data captured from the authentication code displayed in world light 38W includes the authentication pattern or code identified by the authentication request transmitted at step <NUM> (e.g., secondary device <NUM> may then have confidence that the head-mounted device <NUM> that displayed the pattern is the expected head-mounted device <NUM> 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 <NUM>. This is merely illustrative and, in general, any desired authentication algorithm may be used to authenticate the user for that particular head-mounted device <NUM> using the displayed pattern and optionally the other facial image data.

If secondary device <NUM> is unable to authenticate the user for head-mounted device <NUM> (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 <NUM>, 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 <NUM> as shown by path <NUM>. Other operations may also be performed in response to a failure in authentication, such as powering down head-mounted device <NUM>, blocking access to features of head-mounted device <NUM> until authentication can be performed, etc..

If secondary device <NUM> successfully authenticates the user to head-mounted device <NUM>, processing may proceed to step <NUM> as shown by path <NUM>. At step <NUM>, secondary device <NUM> may transmit an authentication confirmation to head-mounted device <NUM>.

At step <NUM>, head-mounted device <NUM> may receive the authentication confirmation from secondary device <NUM>. The authentication confirmation may confirm to head-mounted device <NUM> that the user wearing head-mounted device <NUM> is an authorized user.

At step <NUM>, head-mounted device <NUM> and/or secondary device <NUM> may perform user-authenticated operations. The user-authenticated operations may include any desired operations that require authentication of the user of head-mounted device <NUM>. Such operations may include, for example, allowing head-mounted device <NUM> to power on, beginning to display eye box light 38E to the user, allowing the user to access personal or private data using head-mounted device <NUM>, allowing the user to make purchases using head-mounted device <NUM>, allowing the user to use their log in credentials using head-mounted device <NUM>, enabling certain applications or operations on head-mounted device <NUM>, 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 <NUM> from their head, head-mounted device <NUM> being powered off, the passage of a predetermined amount of time, entry of head-mounted device <NUM> 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> are merely illustrative. Two or more of the steps of <FIG> may be performed at least partially concurrently. The steps of <FIG> may be performed in other orders. Head-mounted device <NUM> may display eye box light 38E (<FIG>) to eye box <NUM> (e.g., to provide augmented reality content to the user) concurrently with one, more than one, or all of the steps of <FIG> (e.g., head-mounted device <NUM> may continue to perform augmented reality operations even while displaying world light 38W).

<FIG> is a flow chart of illustrative steps that may be performed by head-mounted device <NUM> in preventing external cameras from gathering accurate facial recognition information from the user of head-mounted device <NUM>.

At step <NUM>, head-mounted device <NUM> may activate a privacy mode. Head-mounted device <NUM> may activate the privacy mode in response to an input provided by the user of head-mounted device <NUM> (e.g., using an input/output device of head-mounted device <NUM>, via an input/output device of secondary device <NUM>, etc.) or may activate the privacy mode autonomously (e.g., in response to detecting the presence of camera <NUM> of <FIG>, in response to detecting that head-mounted device <NUM> has entered region <NUM>, in response to the operation or call of one or more applications running on head-mounted device <NUM> and/or secondary device <NUM>, etc.). Prior to activating the privacy mode, head-mounted device <NUM> may not display world light 38W (e.g., all cells <NUM> of <FIG> may be unshaded cells 120B) or may be displaying world light 38W for purposes other than protecting the privacy of the user from facial recognition technologies (e.g., to authenticate device <NUM> as shown in <FIG>).

At step <NUM>, head-mounted device <NUM> may display world light 38W to obscure the user's eyes from facial recognition data-gathering external equipment such as camera <NUM> of <FIG>. For example, world output coupler <NUM> may display world light 38W in all cells of the world light (e.g., all cells <NUM> of <FIG> may be shaded cells 120A) or may display world light 38W in a random, pseudorandom, or other pattern. This may serve to prevent camera <NUM> from capturing accurate facial recognition image data of the user's eyes while wearing head-mounted device <NUM> (e.g., at the wavelengths of world light 38W such as NIR wavelengths). By preventing camera <NUM> from capturing accurate facial recognition image data, head-mounted device <NUM> may also prevent camera <NUM> from tracking the user's personal information (e.g., the user's shopping preferences, etc.), because camera <NUM> will be unable to associate the user with a particular user profile.

At step <NUM>, head-mounted device <NUM> may deactivate the privacy mode. Head-mounted device <NUM> may deactivate the privacy mode in response to an input provided by the user of head-mounted device <NUM> (e.g., using an input/output device of head-mounted device <NUM>, via an input/output device of secondary device <NUM>, etc.) or may deactivate the privacy mode autonomously (e.g., in response to detecting that head-mounted device <NUM> has left region <NUM> of <FIG>, in response to the operation or call of one or more applications running on head-mounted device <NUM> and/or secondary device <NUM>, etc.). After deactivating the privacy mode, head-mounted device <NUM> may not display world light 38W (e.g., all cells <NUM> of <FIG> may be unshaded cells 120B) or may be displaying world light 38W for purposes other than protecting the privacy of the user from facial recognition technologies. Head-mounted device <NUM> may display eye box light 38E (<FIG>) to eye box <NUM> (e.g., to provide augmented reality content to the user) concurrently with one, more than one, or all of the steps of <FIG> (e.g., head-mounted device <NUM> may continue to perform augmented reality operations even while displaying world light 38W).

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's, home addresses, data or records relating to a user'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's general wellness, or may be used as positive feedback to individuals using technology to pursue wellness goals.

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.

For example, head-mounted device <NUM> 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'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'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 VR environment through a simulation of the person's presence within the computer-generated environment, and/or through a simulation of a subset of the person'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 in 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'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'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'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.

In accordance with an embodiment, an optical system configured to provide image light to an eye box and configured to be operated in an environment, the optical system is provided that includes, a display module configured to produce the image light, a waveguide having an input coupler configured to couple the image light into the waveguide, the waveguide is configured to transmit environmental light from the environment to the eye box, a first output coupler on the waveguide and configured to couple a first portion of the image light out of the waveguide and towards the eye box, and a second output coupler on the waveguide and at least partially overlapping the first output coupler, the second output coupler is configured to couple a second portion of the image light out of the waveguide and towards the environment.

In accordance with another embodiment, the first portion of the image light includes light at visible wavelengths and the second portion of the image light includes light at near-infrared wavelengths.

In accordance with another embodiment, the second output coupler includes a filter layer on a surface of the waveguide, the filter layer is configured to transmit light at the near-infrared wavelengths and is configured to block light at the visible wavelengths.

In accordance with another embodiment, the first output coupler includes a set of volume holograms that are Bragg-matched to the visible wavelengths.

In accordance with another embodiment, the second output coupler includes an additional filter layer on an additional surface of the waveguide, the additional filter is configured to block light at the near-infrared wavelengths and is configured to transmit light at the visible wavelengths.

In accordance with another embodiment, the first output coupler includes a first set of volume holograms that are Bragg-matched to the visible wavelengths and the second output coupler includes a second set of volume holograms that are Bragg-matched to the near-infrared wavelengths.

In accordance with another embodiment, the display module is configured to include a two-dimensional authentication code for the optical system in the image light and the second output coupler is configured to display the two-dimensional authentication code to the environment in the second portion of the image light.

In accordance with another embodiment, the two-dimensional authentication code includes a plurality of cells, the plurality of cells includes a first set of cells in which the second portion of the image light is coupled out of the waveguide, and the plurality of cells includes a second set of cells in which none of the image light is coupled out of the waveguide.

In accordance with another embodiment, the optical system includes control circuitry configured to activate a privacy mode of the optical system, the display module is configured to, responsive to activation of the privacy mode, produce the image light in a pattern that configures the second portion of the image light to obscure capture of images of the eye box by camera equipment in the environment.

In accordance with another embodiment, the display module is configured to include a two-dimensional pseudorandom pattern of cells in the image light and the second output coupler is configured to display the two-dimensional pseudorandom pattern of cells to the environment in the second portion of the image light.

In accordance with an embodiment, an optical combiner configured to redirect a first portion of image light towards an eye box and configured to pass environmental light towards the eye box, the optical combiner is provided that includes a waveguide having a substrate layer with a first surface facing the eye box and a second surface opposite the first surface, the waveguide is configured to propagate the first portion of the image light and a second portion of the image light via total internal reflection, an input coupler configured to couple the image light into the waveguide, an output coupler configured to couple the first portion of the image light out of the waveguide and towards the eye box, and a filter layer on the second surface of the substrate and at least partially overlapping the output coupler, the filter layer is configured to transmit the second portion of the image light without transmitting the second portion of the image light.

In accordance with another embodiment, the optical combiner includes an additional filter layer on the first surface of the substrate, the additional filter layer is configured to transmit the first portion of the image light without transmitting the second portion of the image light.

In accordance with another embodiment, the filter layer includes a long-pass filter and the additional filter includes a short-pass filter.

In accordance with another embodiment, the output coupler includes an optical component selected from the group consisting of a diffractive grating and a louvered mirror.

In accordance with an embodiment, an optical combiner configured to redirect a first portion of image light towards an eye box and configured to pass environmental light from an exterior environment towards the eye box, the optical combiner is provided that includes
a waveguide, the waveguide is configured to propagate the first portion of the image light and a second portion of the image light via total internal reflection, an input coupler configured to couple the image light into the waveguide, a first holographic optical element on the waveguide and configured to couple the first portion of the image light out of the waveguide and towards the eye box, and a second holographic optical element on the waveguide and at least partially overlapping the first holographic optical element, the second holographic optical element is configured to couple the second portion of the image light out of the waveguide and towards the exterior environment.

In accordance with another embodiment, the first portion of the image light includes light of a first range of wavelengths and the second portion of the image light includes light of a second range of wavelengths.

In accordance with another embodiment, the first range of wavelengths include a wavelength between <NUM> and <NUM> and the second range of wavelengths include a wavelength between <NUM> and <NUM>.

In accordance with an embodiment, an electronic device configured to communicate with a head-mounted device configured to display a pattern of near-infrared light, the electronic device is provided that includes wireless circuitry configured to transmit radio-frequency signals to the head-mounted device, the radio-frequency signals identify an authentication code, an image sensor configured to capture an image of the pattern of near-infrared light displayed by the head-mounted device, and control circuitry coupled to the wireless circuitry and the image sensor, the control circuitry is configured to authenticate the head-mounted device at least by comparing the image of the pattern of near-infrared light to the authentication code identified by the transmitted radio-frequency signals, and responsive to authenticating the head-mounted device, control the wireless circuitry to transmit an authentication confirmation to the electronic device.

In accordance with another embodiment, the image sensor is configured to capture an additional image of light reflected off of a user of the head-mounted device and the control circuitry is configured to authenticate the head-mounted device based on the captured additional image.

Claim 1:
An optical system (20B) configured to provide image light (<NUM>) to an eye box (<NUM>) and configured to be operated in an environment, the optical system (20B) comprising:
a display module (<NUM>, 20A) configured to produce the image light (<NUM>);
a waveguide (<NUM>) having an input coupler (<NUM>) configured to couple the image light (<NUM>) into the waveguide (<NUM>), wherein the waveguide (<NUM>) is configured to transmit environmental light from the environment to the eye box (<NUM>);
a first output coupler on the waveguide (<NUM>) and configured to couple a first portion of the image light (<NUM>) out of the waveguide (<NUM>) and towards the eye box (<NUM>); and
a second output coupler on the waveguide (<NUM>) and at least partially overlapping the first output coupler, wherein the second output coupler is configured to couple a second portion of the image light (<NUM>) out of the waveguide (<NUM>) and towards the environment, and the second portion of the image light (<NUM>) includes a two-dimensional authentication code for the optical system (20B) or a two-dimensional pattern configured to obscure capture of images of the eye box (<NUM>) by camera equipment in the environment.