Abstract: A head-mounted device may include a first display having a first projector and a first waveguide, a second display having a second projector and a second waveguide, first and second cameras, an optical sensor that couples the first waveguide to the second waveguide, and position sensors mounted to the first and second cameras and the optical sensor. The optical sensor may gather image sensor data from first image light propagating in the first waveguide and second image light propagating in the second waveguide. The cameras may capture real-world images. The position sensors may gather position measurements. Control circuitry may calibrate optical misalignment in the device by adjusting the first and/or second image light based on the image sensor data, the position measurements, and/or the world light.

Abstract: An electronic device such as a head mounted device may have a head-mounted support structure. A portion of the head-mounted support structure may form a transparent housing member through which real-world objects can be viewed from eye boxes. A display system for the head-mounted device may have a display device that provides image light to a waveguide and may have an output coupler that couples the image light out of the waveguide toward the eye box. Peripheral portions of the transparent housing member or other peripheral device structures may be provided with a peripheral display that emits diffuse light into a user's peripheral vision. The peripheral display may use light guide structures, light sources, reflective structures, and other structures that provide transparency to real-world light.

Abstract: A head-mounted device may have a left display and a right display that provide respective left and right images. Left and right optical combiner systems may be configured to pass real-world light to left and right eye boxes while directing the left and right images respectively to the left and right eye boxes. Misalignment of the left and right images with respect to the left and right eye boxes may be detected using gaze tracking systems, using cameras such as front-facing cameras in conjunction with a database of known real-world object properties, using visual inertial odometry systems formed from cameras and inertial measurement units, or using one or more sensors in a portable head-mounted device case or other item with a receptacle configured to receive a head-mounted device. Compensating adjustments may be made to the images based on the measured misalignment.

Abstract: Wearable electronic devices can include connection mechanisms for adjustable and exchangeable connections with selected modules other devices to enhance performance of the wearable electronic device. Such connections can provide both mechanical engagement and operable communication between the connected devices. Arms, earpieces, accessory devices, and/or other external devices can be easily connected to provide different components and functions at different times as desired. Accordingly, a main portion of the wearable electronic device need not include permanent components that provide every function that will later be desired by the user. Instead, the wearable electronic device can have expanded and customizable capabilities by the use of one or more arms, earpieces, accessory devices, and/or other external devices.

Abstract: A display system may include a waveguide with an output coupler that couples image light out of the waveguide and towards an eye box. The output coupler may also transmit world light from real-world objects towards the eye box. A bias lens may pass the world light to the output coupler. An adjustable tint layer having multiple states that involve transmission of different amounts of the world light may be disposed between the bias lens and the output coupler. Different states may impart different colors and/or may impart a gradient transmission characteristic to the world light. The bias lens itself may form the adjustable tint layer. The adjustable tint layer may have a transparent electrode layer that is provided with one or more AC voltages that heat the adjustable tint layer. The adjustable tint layer may be a self-switching electrochromic device that includes a transparent solar cell.

Abstract: A head-mounted device may have a left display and a right display that provide respective left and right images. Left and right optical combiner systems may be configured to pass real-world light to left and right eye boxes while directing the left and right images respectively to the left and right eye boxes. Misalignment of the left and right images with respect to the left and right eye boxes may be detected using gaze tracking systems, using cameras such as front-facing cameras in conjunction with a database of known real-world object properties, using visual inertial odometry systems formed from cameras and inertial measurement units, or using one or more sensors in a portable head-mounted device case or other item with a receptacle configured to receive a head-mounted device. Compensating adjustments may be made to the images based on the measured misalignment.

Abstract: Methods and apparatus for measuring biometric data including temperature in head-mounted devices (HMDs). Thermal sensors may also be integrated into the HMD and used to collect thermal data from the surface of the user's face. This thermal data may, for example, be processed to determine core body temperature of the user, or be processed to generate estimates of the user's respiration. The temperature data and/or respiration rate and changes to respiration rate derived from signals from the sensors may be used to generate and present biometric data to the user.

Abstract: A head-mounted device may include near-eye displays and gaze tracking components to track a user's gaze. The head-mounted device may include an optical system, including a waveguide and optional lenses to guide images produced by display modules to an eye box. The gaze tracking components may include infrared emitters that emit infrared light toward the user's eyes and infrared sensors that detect infrared light that has been reflected from the user's eyes. To reduce interference with the gaze tracking components from environmental infrared light, the optical system may include an infrared-reflective coating and an infrared-absorptive coating. The infrared-reflective and infrared-absorptive coatings may be formed on the optional lenses or on other transparent structures in the optical system.

Abstract: A compliant interface for a wearable electronic device includes a three-dimensional lattice structure that is coupleable to the wearable electronic device and compressible to conform to one or more of a facial feature or an upper cranial feature of a user wearing the wearable electronic device. The compliant interface may be one of a facial interface of a head-mounted display unit, a head interface of a head-mounted display unit, or a head interface of a headphones unit. The three-dimensional lattice structure may be formed of silicone that may form less than 35% of a volume of the three-dimensional lattice structure in an uncompressed state. Compliance of the facial interface may vary by locations at which the compliant interface engages the user. The compliance may vary according to one or more of geometric stiffness or maximum deflection of the three-dimensional lattice structure.

Abstract: A display may include a waveguide having an output coupler that couples image light out of the waveguide and towards a lens, which imparts a first power to the image light. A cover layer may have an outer surface with a three-dimensional curvature and an inner surface. A portion of the inner surface overlapping the output coupler may have a different three-dimensional curvature that forms an additional lens in the cover layer that transmits world light to the output coupler. The output coupler may transmit the world light to the lens, which transmits the world and image light to the eye box. The curvature of the portion of the inner surface may impart power to the world light that reverses the first power and/or a power imparted to the world light by the outer surface of the cover layer.

Abstract: A wearable apparatus can include a head-mountable device that includes: a display, a display frame housing the display, arms connected to the display frame, a processor, and a battery electrically coupled to the processor. In addition, the wearable apparatus can include a wearable power device connectable to the battery of the head-mountable device when the head-mountable device is worn on a person or a clothing of the person.

Abstract: A head-mounted device may include a housing having openings that receive lenses. Displays may output images. Waveguides that overlap the lenses may receive the images from the displays and may direct the images to eye boxes that are aligned with the lenses. Infrared light sources such as infrared light-emitting diodes or lasers may be used to supply infrared light to the waveguides. Each waveguide may have multiple localized output couplers that overlap the lenses. The localized output couplers of each lens each direct a beam of the infrared light out of the waveguide towards an eye surface in the eye box associated with that lens to produce an eye glint. A gaze tracker infrared camera may captured images of the eye glints to determine a user's point of gaze.

Abstract: A head-mounted device may have a housing with a frame that supports lenses. Each lens may have a positive bias lens element and a negative bias lens element. A waveguide may overlap the lens. During operation, images from the waveguide may be provided to an eye box through the negative bias lens element. An eye sensor such as a gaze tracking camera may operate through the negative bias lens element. The negative bias lens element may have a protruding portion through which the sensor operates, may have a surface facing the sensor that has a curved surface to provide a desired lens characteristic, may have a prism for helping to couple light from the eye box to the eye sensor, and/or may have other features to facilitate use of the eye sensor to monitor the eye of a user in the eye box.

Abstract: Eyewear such as a head-mounted device may include display-optimized lenses. The lenses may be optimized for viewing an external display while also providing sun protection for the user's eyes. The external display may form part of a handheld electronic device that serves as a controller for the head-mounted device. The lenses in the head-mounted device may reduce ambient light brightness while maintaining the brightness of the external display so that the user can use the external display while wearing the head-mounted device. The user may, for example, provide touch input to the external display to adjust display content on the head-mounted display. The lenses may include a polarizer and a color filter having a transmission spectrum curve with peaks corresponding to the primary colors of the external display. The lenses may be removable clip-on lenses and the light filter may be an electrochromic filter.

Abstract: A head-mounted device may have a left display and a right display that provide respective left and right images. Left and right optical combiner systems may be configured to pass real-world light to left and right eye boxes while directing the left and right images respectively to the left and right eye boxes. Misalignment of the left and right images with respect to the left and right eye boxes may be detected using gaze tracking systems, using cameras such as front-facing cameras in conjunction with a database of known real-world object properties, using visual inertial odometry systems formed from cameras and inertial measurement units, or using one or more sensors in a portable head-mounted device case or other item with a receptacle configured to receive a head-mounted device. Compensating adjustments may be made to the images based on the measured misalignment.

Abstract: Head-mountable devices can include a light projection display element that is directly coupled to an assembly that includes a waveguide. Such a direct coupling can be achieved by bonding the light projection display element directly to a lens or other optical component that is, in turn, directly coupled to the waveguide. Such an optical module can be assembled outside of the head-mountable device for precision alignment and subsequently installed as an integrated unit. These measures can help maintain component alignment while allowing a head-mountable device to be lightweight and small in size.

Abstract: Head-mountable devices can include connection mechanisms that provide adjustable and exchangeable connections with other devices to enhance performance of the head-mountable device. Such connections can provide both mechanical engagement and operable communication between the connected devices. Accessory devices and/or external devices can be easily connected to provide different components and functions at different times as desired. Accordingly, a main portion of the head-mountable device need not include permanent components that provide every function that will later be desired by the user. Instead, the head-mountable device can have expanded and customizable capabilities by the use of one or more accessory devices.

Abstract: A head-mounted device may have a left display and a right display that provide respective left and right images. Left and right optical combiner systems may be configured to pass real-world light to left and right eye boxes while directing the left and right images respectively to the left and right eye boxes. Misalignment of the left and right images with respect to the left and right eye boxes may be detected using gaze tracking systems, using cameras such as front-facing cameras in conjunction with a database of known real-world object properties, using visual inertial odometry systems formed from cameras and inertial measurement units, or using one or more sensors in a portable head-mounted device case or other item with a receptacle configured to receive a head-mounted device. Compensating adjustments may be made to the images based on the measured misalignment.

Abstract: Head-mountable devices can include adjustment mechanisms to achieve optimal alignment of optical components during and/or after assembly thereof within the head-mountable device. The alignment mechanisms can be integrated into the head-mountable device itself. A light projecting display element can be adjustable based on movement of ramp members within the head-mountable device (e.g., within an arm) to adjust an orientation of the light projecting display element relative to the waveguide onto which it projects light. Alignment can be verified based on the optical output of the display element. The adjustment mechanisms can adjust the display element during initial assembly and/or be operated by actuators that actively adjust the alignment as needed over time.

Abstract: Head-mountable devices can provide comfortable securement to a head of a user while also providing operative connections for communication across a hinge of the head-mountable device. The securement can be based on an arrangement of spring elements that have biased configurations and allow gentle retraction against a head of the user. Head-mountable devices of the present disclosure can provide adjustable securement against a head of a user by allowing custom fitting, for example with a tensioner.