Abstract: An electronic device includes a shared epitaxial structure, an array of photodiodes formed in the shared epitaxial structure, and a readout circuit. The array of photodiodes is disposed between a first axis and a second axis, with the second axis orthogonal to the first axis. The array of photodiodes has an absence of guard structures between adjacent photodiodes. The readout circuit is electrically connected to the array of photodiodes and operable to read out values for different photodiodes or different subsets of photodiodes in the array of photodiodes.

Abstract: An assembly includes a rotatable and translatable input device having an axis of rotation, a circumference about the axis of rotation, and an optical encoder pattern disposed around the circumference. The optical encoder pattern includes a series of polygon facets about the circumference and a one-dimensional substantially retroreflective feature parallel to the axis of rotation. The assembly further includes an optical emitter configured to emit electromagnetic radiation toward the optical encoder pattern, and an optical receiver including a two-dimensional array of pixels. The optical receiver is configured to receive reflections of the emitted electromagnetic radiation from the optical encoder pattern and generate an irradiance pattern in response to the reflections. The optical emitter and the optical receiver are disposed along a sensing axis orthogonal to the axis of rotation.

Abstract: An electronic device may include a housing and relative humidity sensor in the housing. The relative humidity sensor may include an optical layer, a relative humidity-sensitive layer coupled to a surface of the optical layer, a light emitter that emits light into the optical layer, and a light detector that detects light that has reflected within the optical layer and off of the relative humidity-sensitive layer. The relative humidity may be determined based on the light detected by the light detector. The optical layer may be a layer with angled edges, a prism, a Bragg reflector, or a waveguide. A reference light detector and/or a temperature sensor may be included in the relative humidity sensor, and measurements from these additional sensors may be used in determining the relative humidity. In this way, an optical relative humidity sensor may be formed in the electronic device.

Abstract: An electronic device may include a housing and relative humidity sensor in the housing. The relative humidity sensor may include a relative humidity-sensitive layer, a light emitter that emits light into the relative humidity-sensitive layer, and a light detector that detects light that has passed through the relative humidity-sensitive layer. The relative humidity may be determined based on the detected light. For example, the light may be measured interferometrically to determine a path length of the light to determine the relative humidity. Alternatively, the light may be scattered by plasmonic nanoparticles in a relative humidity-sensitive material to determine the relative humidity. As other examples, polarized light may pass through the relative humidity-sensitive layer and measured to determine the relative humidity, or light may be used to form sound waves that may be measured to determine the relative humidity.

Abstract: A system may include an electronic device such as a head-mounted device and a handheld controller for controlling the electronic device. The handheld controller may have a housing with an elongated shaft extending between first and second tip portions. A removable tip member may be coupled to the first tip portion. A position sensor may be located in the removable tip member and may be used to track surface markings made with the handheld controller on a surface. The position sensor may be an optical flow sensor, a visual inertial odometry camera, an interferometer, or other sensor. A force sensor at the first tip portion may be used to detect when the tip contacts a surface. The position sensor may switch from air input mode to surface marking mode in response to detecting contact with the surface.

Abstract: Hat, helmet, and other headgear apparatus includes dry electrophysiological electrodes and, optionally, other physiological and/or environmental sensors to measure signals such as ECG from the head of a subject. Methods of use of such apparatus to provide fitness, health, or other measured or derived, estimated, or predicted metrics are also disclosed.

Abstract: A multi-channel SMI sensor includes an emitter configured to emit light having different polarizations and a polarization-selective lens for directing light having different polarizations towards different locations. The multi-channel SMI sensor is configured to measure physical phenomena at two different locations with a small footprint.

Abstract: A watch body includes a housing at least partially defining an interior of the watch body. A retaining feature is formed in or extends from the housing. A watch crown is retained by the retaining feature and is operable to be rotated by a user. The watch crown has a surface facing the housing. The watch crown is entirely external to the interior of the watch body. An electromagnetic radiation source is disposed within the housing and is operable to emit a beam of electromagnetic radiation toward the surface. A sensor is disposed within the housing and is operable to characterize a movement of the watch crown based at least in part on a portion of the beam of electromagnetic radiation that impinges on the surface and is redirected by the surface.

Abstract: An electronic device is described. The electronic device may include a housing, a rotatable crown, and a self-mixing interferometry (SMI) sensor positioned within the housing. The rotatable crown may include an array of retroreflective surface features that reflect incident light back to a light source. Each retroreflective surface feature of the array of retroreflective surface features may be formed as a corner-cube with three perpendicular faces. The SMI sensor or associated processing electronics may compare originally emitted light with reflected light to identify a movement or distance of the rotatable crown with respect to the SMI sensor.

Abstract: An electronic watch may include a housing defining a side wall, a display, a front cover positioned over the display, and an input system configured to receive a rotational input and a translational input. The input system may include a crown including a knob external to the housing and a rotor coupled to the knob and configured to rotate in response to the rotational input and translate in response to the translational input. The input system may further include a first laser module configured to direct a first laser beam onto the rotor and receive first reflected light from the rotor, a second laser module configured to direct a second laser beam onto the rotor and receive second reflected light from the rotor. The electronic watch may further include a processing system coupled to the first and second laser modules and configured to determine a parameter of the rotational input.

Abstract: An electronic device can include housing with first and second housing portions configured to rotate relative to one another about a hinge, a hinge angle encoder that rotates with the hinge, an emitter that emits light towards the hinge angle encoder, and a sensor die that receives light reflecting back from the hinge angle encoder. The hinge angle encoder may include an absorptive polarizing filter layer and a reflective diffuser layer. A pixelated polarizer may be formed overlapping an array of photodetectors in the sensor die. The electronic device may include processing circuitry configured to compute a hinge angle by which the first and second housing portions are rotated based on one or more intensity values acquired using the array of photodetectors.

Abstract: An electronic device may be attached to an external item. The electronic device may include an optical identification sensor configured to sense a color-encoded tag in the external item when the item is attached to the device. The optical identification sensor may include a board layer, a protective filter layer, wall structures for supporting the protective filter layer on the board layer, a linear array of photodetectors disposed between the board layer and the protective filter layer, a field-of-view restriction filter interposed between the photodetectors and the protective filter layer, and a light source having multiple emitters for illuminating the color-encoded tag. The emitters may be activated sequentially to produce multiple images that are combined to reconstruct an accurate reading of the color-encoded tag, which can then be used to identify the type of external item currently attached to the electronic device.

Abstract: Hat, helmet, and other headgear apparatus includes dry electrophysiological electrodes and, optionally, other physiological and/or environmental sensors to measure signals such as ECG from the head of a subject. Methods of use of such apparatus to provide fitness, health, or other measured or derived, estimated, or predicted metrics are also disclosed.

Abstract: Earphone apparatus includes dry electrophysiological electrodes and, optionally, other physiological and/or environmental sensors to measure signals such as ECG from the head of a subject. Methods of use of such apparatus to provide fitness, health, or other measured or derived, estimated, or predicted metrics are also disclosed.

Abstract: A watch can include a watch body and a band for securing the watch to the user. The watch body can detect an identification of the band or combination of band portions, which can serve as an input to initiate actions performed by the watch body. For example, a type, model, color, size, or other characteristic of a band can be determined and used to select a corresponding action performed by the watch body. Identification of the band can be performed by components of the watch body that also serve other purposes. The watch body can respond to the identification of a particular band by performing particular functions, such as changing an aspect of a user interface or altering settings of the watch body.

Abstract: An electronic device may be attached to an external item. The electronic device may include an optical identification sensor configured to sense a color-encoded tag in the external item when the item is attached to the device. The optical identification sensor may include a board layer, a protective filter layer, wall structures for supporting the protective filter layer on the board layer, a linear array of photodetectors disposed between the board layer and the protective filter layer, a field-of-view restriction filter interposed between the photodetectors and the protective filter layer, and a light source having multiple emitters for illuminating the color-encoded tag. The emitters may be activated sequentially to produce multiple images that are combined to reconstruct an accurate reading of the color-encoded tag, which can then be used to identify the type of external item currently attached to the electronic device.

Abstract: Eyewear apparatus includes dry electrophysiological electrodes and, optionally, other physiological and/or environmental sensors to measure signals such as EOG and ECG from the head of a subject. Methods of use of such apparatus to provide fitness, health, or other measured or derived, estimated, or predicted metrics are also disclosed.

Abstract: An electronic device may be attached to an external item. The electronic device may include an optical identification sensor configured to sense a color-encoded tag in the external item when the item is attached to the device. The optical identification sensor may include a board layer, a protective filter layer, wall structures for supporting the protective filter layer on the board layer, a linear array of photodetectors disposed between the board layer and the protective filter layer, a field-of-view restriction filter interposed between the photodetectors and the protective filter layer, and a light source having multiple emitters for illuminating the color-encoded tag. The emitters may be activated sequentially to produce multiple images that are combined to reconstruct an accurate reading of the color-encoded tag, which can then be used to identify the type of external item currently attached to the electronic device.

Abstract: A watch body includes a housing at least partially defining an interior of the watch body. A retaining feature is formed in or extends from the housing. A watch crown is retained by the retaining feature and is operable to be rotated by a user. The watch crown has a surface facing the housing. The watch crown is entirely external to the interior of the watch body. An electromagnetic radiation source is disposed within the housing and is operable to emit a beam of electromagnetic radiation toward the surface. A sensor is disposed within the housing and is operable to characterize a movement of the watch crown based at least in part on a portion of the beam of electromagnetic radiation that impinges on the surface and is redirected by the surface.

Abstract: An electronic device is described. The electronic device may include a housing, a rotatable crown, and a self-mixing interferometry (SMI) sensor positioned within the housing. The rotatable crown may include an array of retroreflective surface features that reflect incident light back to a light source. Each retroreflective surface feature of the array of retroreflective surface features may be formed as a corner-cube with three perpendicular faces. The SMI sensor or associated processing electronics may compare originally emitted light with reflected light to identify a movement or distance of the rotatable crown with respect to the SMI sensor.