Abstract: An electronic device may include an ambient light sensor or other semiconductor sensor. The sensor may produce signals in response to light incident on the electronic device and therefore incident on the sensor. In some cases, components within the electronic device, such as infrared components, or external light sources may interfere with the operation of the sensor. Therefore, the sensor may include a filter that transmits at least a portion of visible light while blocking infrared light. Because light may be incident on the electronic device from a variety of angles, a diffuser in the sensor may scatter the light into a desired angular distribution. To ensure that infrared light is blocked regardless of the angle of the incident light, the filter may include both thin-film dielectric layers and metal layers. The metal layers may be interleaved with the thin-film dielectric layers.

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 optical modules that present images to a user's left and right eyes. Each optical module may have a lens support structure that supports a display and a fixed lens. Vision correction lenses may be removably coupled to the fixed lenses to help customize the head-mounted device to the vision of a particular user. A user may view images on the displays through the removable and fixed lenses from eye boxes. The optical modules may include infrared light sources that supply infrared light to the eye boxes and infrared light sensors such as infrared cameras for gaze tracking and authentication. The lenses may have optical surfaces covered with coating that enhance optical performance and may have edge surfaces that are provided with structures to help reduce stray light reflections. The lenses may be configured to pass visible and infrared light.

Abstract: Eyewear such as sunglasses may include display-optimized lenses. The lenses may be optimized for viewing an external display and/or for viewing a display in the head-mounted device while also providing sun protection for the user's eyes. The lenses may include a polarizer and a color filter that are designed for a given target display. Lenses that are optimized for a display that emits linearly polarized light may include a linear polarizer. Lenses that are optimized for a display that emits circularly polarized light may include a circular polarizer. The circular polarizer may include a quarter wave plate and a linear polarizer. The color filter may have a transmission spectrum curve with peaks corresponding to the primary colors of the target display so that the color and brightness of display light is preserved while the brightness of sunlight is reduced.

Abstract: An electronic device may be surrounded by an exterior region and may have an interior region. Electronic components may be mounted in the interior region. Housing walls such as housing walls formed from transparent layers of material may separate the interior region from the exterior region. A display may be visible through one of the transparent layers of material. A transparent layer of material may be coupled to housing structures in the device and may be formed of glass or glass-ceramic. The transparent layer may have two opposing chemically strengthened surface layers of different thicknesses. A coating may be formed on a thinner of the two opposing chemically strengthened surface layers. The coating may have an oleophobic outer coating layer, an antireflection layer, and an antiscratch layer. The antiscratch layer may have one or more compressively stressed dielectric layers and may have one or more corresponding graded composition layers.

Abstract: An electronic device may be provided with input-output devices and other components such as optical components that emit light and optical components that detect light. An optical component covering structure may be interposed between an interior region of the electronic device and an exterior region that surrounds the electronic device. The optical components may be formed in the interior region of the electronic device. The optical component covering structure may overlap the optical components. The optical component covering structure may be configured to exhibit a flat visible light transmission spectrum. This neutral light transmission characteristic allows the overlapped optical components to emit and/or receive light through the optical component covering structure without imposing an undesired color cast. The optical component covering structure may include first and second layers with complementary light transmission characteristics.

Abstract: An electronic device may have a housing surrounding an interior in which electrical components are mounted. A display may be mounted to housing structures in the device. The housing may have a rear wall. The display cover layer and rear wall of the housing may be formed from transparent glass layers. Coatings may be formed on inwardly facing surfaces of the transparent glass layers. A coating on a transparent glass layer may be formed from a thin-film interference filter having a stack of dielectric layers. The coating may include an ink layer on the thin-film interference filter.

Abstract: An electronic device may have a housing surrounding an interior in which electrical components are mounted. A display may be mounted to housing structures in the device. The housing may have a rear wall. The display cover layer and rear wall of the housing may be formed from transparent glass layers. Coatings may be formed on inwardly facing surfaces of the transparent glass layers. A coating on a transparent glass layer may be formed from a thin-film interference filter having a stack of dielectric layers. The coating may include an ink layer on the thin-film interference filter.

Abstract: An electronic device may have a housing with a display. A transparent portion of the housing may serve as a display cover layer and may overlap an array of pixels in the display. The array of pixels may form an active area of the display for displaying images for a user. An ambient light sensor window may be formed in an inactive area of the display that does not overlap pixels. An ambient light sensor may be mounted in an interior region of the housing. A metal-coated light guide may have a first end aligned with the ambient light sensor window to receive ambient light from an exterior region surrounding the device and may have a second end at which the ambient light is provided to the ambient light sensor.

Abstract: An electronic device may be provided with a color ambient light sensor. The color ambient light sensor may be used to measure an ambient light spectrum over a wavelength range of interest. Control circuitry in the electronic device can take actions based on the measured ambient light spectrum such as adjusting the brightness and color cast of content on a display. A display may have a display cover layer. The color ambient light sensor can be mounted under the display cover layer and may receive ambient light through the display cover layer. The color ambient light sensor may have a tunable wavelength filter such as an electrically adjustable Fabry-Perot resonator. A light collimator may be interposed between the display cover layer and the Fabry-Perot resonator to collimate ambient light that is passed to the Fabry-Perot resonator. A light detector measures the light passing through the Fabry-Perot resonator.

Abstract: An electronic device may be provided with input-output devices and other components such as optical components that emit light and optical components that detect light. An optical component covering structure may be interposed between an interior region of the electronic device and an exterior region that surrounds the electronic device. The optical components may be formed in the interior region of the electronic device. The optical component covering structure may overlap the optical components. The optical component covering structure may be configured to exhibit a flat visible light transmission spectrum. This neutral light transmission characteristic allows the overlapped optical components to emit and/or receive light through the optical component covering structure without imposing an undesired color cast. The optical component covering structure may include first and second layers with complementary light transmission characteristics.

Abstract: A display may have display layers that form an array of pixels. The display layers may include a first layer that includes a light-blocking matrix and a second layer that overlaps the first layer. The first layer may include quantum dot elements formed in openings in the light-blocking matrix. The light-blocking matrix may be formed from a reflective material such as metal. The second layer may include color filter elements that overlap corresponding quantum dot elements in the first layer. Substrate layers may be used to support the first and second layers and to support thin-film transistor circuitry that is used in controlling light transmission through the array of pixels. The display layers may include a liquid crystal layer, polarizer layers, filter layers for reflecting red and green light and/or other light to enhance light recycling, and layers with angularly dependent transmission characteristics.

Abstract: An electronic device may be provided with a color ambient light sensor. The color ambient light sensor may be used to measure an ambient light spectrum over a wavelength range of interest. Control circuitry in the electronic device can take actions based on the measured ambient light spectrum such as adjusting the brightness and color cast of content on a display. A display may have a display cover layer. The color ambient light sensor can be mounted under the display cover layer and may receive ambient light through the display cover layer. The color ambient light sensor may have a tunable wavelength filter such as an electrically adjustable Fabry-Perot resonator. A light collimator may be interposed between the display cover layer and the Fabry-Perot resonator to collimate ambient light that is passed to the Fabry-Perot resonator. A light detector measures the light passing through the Fabry-Perot resonator.

Abstract: An electronic device may be provided with a display mounted in a housing. The display may have an array of pixels that form an active area and may have an inactive area that runs along an edge of the active area. An opaque layer may be formed on an inner surface of a display cover layer in the inactive area of the display or may be formed on another transparent layer in the electronic device. An ambient light sensor window may be formed from the opening and may be aligned with color ambient light sensor. The ambient light sensor may have an integrated circuit with an array of photodetectors and may have a color filter layer forming a corresponding array of thin-film interference color filters with different respective pass bands. The color filter layer may have a shared dielectric stack and multiple color-filter-specific dielectric stacks on the shared dielectric stack.

Abstract: An electronic device may be provided with a display. The display may have an array of pixels that form an active area and may have an inactive area that runs along an edge of the active area. An opaque layer may be formed on an inner surface of a display cover layer in the inactive area of the display or may be formed on another transparent layer in the electronic device. An ambient light sensor window may be formed from the opening and may be aligned with color ambient light sensor. The ambient light sensor may have an integrated circuit with photodetectors. Ambient light passing through the ambient light sensor window may be diffused by a light diffuser having one or more light-diffusing layers. Diffused ambient light may be collimated using a light collimator having one or more light-collimating layers such as layers with inwardly facing protrusions.

Abstract: An electronic device may be provided with a display. An opaque layer may be formed on an inner surface of a display cover layer in an inactive area of the display. An optical component window may be formed from the opening. A light guide may be aligned with the optical component window and may be used to guide light from the optical component window to an optical component such as an ambient light sensor. The light guide may have a core surrounded by a cladding. The core may be formed from a material such as blue glass that absorbs infrared light and that transmits visible light. Particles of titanium dioxide or other high-refractive-index material may be incorporated into the core to enhance the refractive index of the core. Thin-film interference filters may be formed on the light guide to enhance infrared light blocking.

Abstract: An electronic device may be provided with a display. The display may have an array of pixels that form an active area and may have an inactive area that runs along an edge of the active area. An opaque layer may be formed on an inner surface of a display cover layer in the inactive area of the display or may be formed on another transparent layer in the electronic device. An ambient light sensor window may be formed from the opening and may be aligned with color ambient light sensor. The ambient light sensor may have an integrated circuit with photodetectors. Ambient light passing through the ambient light sensor window may be diffused by a light diffuser having one or more light-diffusing layers. Diffused ambient light may be collimated using a light collimator having one or more light-collimating layers such as layers with inwardly facing protrusions.

Abstract: An electronic device may be provided with a display mounted in a housing. The display may have an array of pixels that form an active area and may have an inactive area that runs along an edge of the active area. An opaque layer may be formed on an inner surface of a display cover layer in the inactive area of the display or may be formed on another transparent layer in the electronic device. An ambient light sensor window may be formed from the opening and may be aligned with color ambient light sensor. The ambient light sensor may have an integrated circuit with an array of photodetectors and may have a color filter layer forming a corresponding array of thin-film interference color filters with different respective pass bands. The color filter layer may have a shared dielectric stack and multiple color-filter-specific dielectric stacks on the shared dielectric stack.

Abstract: An electronic device may have a housing surrounding an interior in which electrical components are mounted. A display may be mounted to housing structures in the device. The housing may have a rear wall. The display cover layer and rear wall of the housing may be formed from transparent glass layers. Coatings may be formed on inwardly facing surfaces of the transparent glass layers. A coating on a transparent glass layer may be formed from a thin-film interference filter having a stack of dielectric layers. The coating may include an ink layer on the thin-film interference filter.

Abstract: A display may have display layers that form an array of pixels. The display layers may include a first layer that includes a light-blocking matrix and a second layer that overlaps the first layer. The first layer may include quantum dot elements formed in openings in the light-blocking matrix. The light-blocking matrix may be formed from a reflective material such as metal. The second layer may include color filter elements that overlap corresponding quantum dot elements in the first layer. Substrate layers may be used to support the first and second layers and to support thin-film transistor circuitry that is used in controlling light transmission through the array of pixels. The display layers may include a liquid crystal layer, polarizer layers, filter layers for reflecting red and green light and/or other light to enhance light recycling, and layers with angularly dependent transmission characteristics.