Abstract: A display may have a pixel array such as a liquid crystal pixel array. The pixel array may be illuminated with backlight illumination from a direct-lit backlight unit. The backlight unit may include an array of light-emitting diodes (LEDs) on a printed circuit board. The display may have a notch to accommodate an input-output component. Reflective layers may be included in the notch. The backlight may include a color conversion layer with a property that varies as a function of position. The light-emitting diodes may be covered by a slab of encapsulant with recesses in an upper surface.

Abstract: A system may have a display that includes a plurality of light sources such as light-emitting diodes. The display may be an exterior display that is routinely operated in daytime conditions where ambient light levels are very high. To increase contrast in an exterior display, the display may include a sunlight blocking element. A static sunlight blocking element may include a louver film with asymmetric light blocking portions. The system may include an ambient light sensor that is configured to determine ambient light levels. Based on the detected ambient light level, control circuitry in the system may adjust one or more adjustable components in the display. The display may include an adjustable diffuser that has at least two states with different haze levels. The display may include an adjustable tint layer that has at least two states with different transmission levels.

Abstract: An electronic device may include a projection display that has a high transparency when the display is turned off. The high off-state transparency may create the appearance of the display being invisible in the off-state, which may be desirable in certain electronic devices. The projection display may include an adjustable diffuser, a spatial light modulator that projects images onto the adjustable diffuser, a mirror that reflects the images from the spatial light modulator to the adjustable diffuser, and a light source that provides light to the spatial light modulator. The projection display may also include an adjustable opacity layer that is controlled based on detected ambient light levels. The projection display may also include an adjustable reflectivity layer. The adjustable diffuser and/or light source may be pixelated to increase contrast in the projection display.

Abstract: A display may have a pixel array such as a liquid crystal pixel array. The pixel array may be illuminated with backlight illumination from a direct-lit backlight unit. The backlight unit may include an array of light-emitting diodes (LEDs) on a printed circuit board. The display may have a notch to accommodate an input-output component. Reflective layers may be included in the notch. The backlight may include a color conversion layer with a property that varies as a function of position. The light-emitting diodes may be covered by a slab of encapsulant with recesses in an upper surface.

Abstract: An electronic device may have a display with an array of pixels configured to display images for a user. The electronic device may have an ambient light sensor for gathering ambient light information. A set of the pixels may overlap the ambient light sensor so that ambient light measurements may be made on ambient light passing through the set of pixels. Control circuitry in the electronic device may control light transmission through the set of pixels so that different light transmission levels can be used in different ambient light conditions. Directional light measurements may be made by moving transparent pixels dynamically across the surface of the display overlapping the light sensor and/or by using pixelated light modulators to vary the angle of light rays measured by the ambient light sensor.

Abstract: A system may have a display that includes a plurality of light sources such as light-emitting diodes. The display may be an exterior display that is routinely operated in daytime conditions where ambient light levels are very high. To increase contrast in an exterior display, the display may include a sunlight blocking element. A static sunlight blocking element may include a louver film with asymmetric light blocking portions. The system may include an ambient light sensor that is configured to determine ambient light levels. Based on the detected ambient light level, control circuitry in the system may adjust one or more adjustable components in the display. The display may include an adjustable diffuser that has at least two states with different haze levels. The display may include an adjustable tint layer that has at least two states with different transmission levels.

Abstract: An electronic device may have a camera. The camera may capture still and moving images. A camera status indicator may be included in the electronic device. The camera status indicator may emit light to indicate when the camera is in use capturing video or other images. The camera status indicator may have multiple light-emitting devices such as light-emitting diodes or lasers. The light-emitting devices may have different colors. Clear encapsulant may cover the light-emitting devices. A white polymer wall or other light recycling structure may run along an outer peripheral edge of the encapsulant. A light diffusing coating layer may coat an outer surface of the clear encapsulant. Light reflections from the status indicator may be reduced in captured images.

Abstract: A display may have a pixel array such as a liquid crystal pixel array. The pixel array may be illuminated with backlight illumination from a direct-lit backlight unit. The backlight unit may include an array of light-emitting diodes (LEDs) on a printed circuit board. The display may have a notch to accommodate an input-output component. Reflective layers may be included in the notch. The backlight may include a color conversion layer with a property that varies as a function of position. The light-emitting diodes may be covered by a slab of encapsulant with recesses in an upper surface.

Abstract: A display may have a pixel array such as a liquid crystal pixel array. The pixel array may be illuminated with backlight illumination from a direct-lit backlight unit. The backlight unit may include an array of light-emitting diodes (LEDs) on a printed circuit board. The display may have a notch to accommodate an input-output component. Reflective layers may be included in the notch. The backlight may include a color conversion layer with a property that varies as a function of position. The light-emitting diodes may be covered by a slab of encapsulant with recesses in an upper surface.

Abstract: A display may have a pixel array such as a liquid crystal pixel array. The pixel array may be illuminated with backlight illumination from a backlight unit. The backlight unit may include a printed circuit board, a plurality of light-emitting diodes mounted on the printed circuit board, at least one light spreading layer formed over the printed circuit board that spreads light received from the plurality of light-emitting diodes, a partially reflective layer formed over the at least one light spreading layer, a color conversion layer formed over the partially reflective layer, a collimating layer formed over the color conversion layer, a brightness enhancement film formed over the collimating layer, and a diffuser formed over the brightness enhancement film. The at least one light spreading layer may include two light spreading layers with elongated protrusions that are rotated relative to each other.

Abstract: An electronic device may have electrical components mounted in an interior region of the electronic device. A housing may surround the interior region and may separate the interior region from an exterior region that surrounds the electronic device. Arrays of recesses may be formed on opposing inner and outer sides of the housing. The arrays may be laterally offset from each other along the housing. The recesses on the inner and outer sides of the housing may meet at passageways within the housing. During operation of the electronic device, air may flow through the inner recesses, the passageways, and the outer recesses to cool electrical components within the interior region. Lighting may be provided for the housing. Light-emitting devices such as light-emitting diodes may be received within cavities in the housing. Light guiding structures, diffusers, reflectors, and other structures may be used to help adjust illumination from the light-emitting devices.

Abstract: A display may have a pixel array such as a liquid crystal pixel array. The pixel array may be illuminated with backlight illumination from a backlight unit. The backlight unit may include a printed circuit board, a plurality of light-emitting diodes mounted on the printed circuit board, at least one light spreading layer formed over the printed circuit board that spreads light received from the plurality of light-emitting diodes, a partially reflective layer formed over the at least one light spreading layer, a color conversion layer formed over the partially reflective layer, a collimating layer formed over the color conversion layer, a brightness enhancement film formed over the collimating layer, and a diffuser formed over the brightness enhancement film. The at least one light spreading layer may include two light spreading layers with elongated protrusions that are rotated relative to each other.

Abstract: A display may have a pixel array such as a liquid crystal pixel array. The pixel array may be illuminated with backlight illumination from a backlight unit. The backlight unit may include a printed circuit board, a plurality of light-emitting diodes mounted on the printed circuit board, at least one light spreading layer formed over the printed circuit board that spreads light received from the plurality of light-emitting diodes, a partially reflective layer formed over the at least one light spreading layer, a color conversion layer formed over the partially reflective layer, a collimating layer formed over the color conversion layer, a brightness enhancement film formed over the collimating layer, and a diffuser formed over the brightness enhancement film. The at least one light spreading layer may include two light spreading layers with elongated protrusions that are rotated relative to each other.

Abstract: An electronic device may have a display with an array of pixels configured to display images for a user. The electronic device may have an ambient light sensor for gathering ambient light information. A set of the pixels may overlap the ambient light sensor so that ambient light measurements may be made on ambient light passing through the set of pixels. Control circuitry in the electronic device may control light transmission through the set of pixels so that different light transmission levels can be used in different ambient light conditions. Directional light measurements may be made by moving transparent pixels dynamically across the surface of the display overlapping the light sensor and/or by using pixelated light modulators to vary the angle of light rays measured by the ambient light sensor.

Abstract: A display may have a pixel array such as a liquid crystal pixel array. The pixel array may be illuminated with backlight illumination from a backlight unit. The backlight unit may include a printed circuit board, a plurality of light-emitting diodes mounted on the printed circuit board, at least one light spreading layer formed over the printed circuit board that spreads light received from the plurality of light-emitting diodes, a partially reflective layer formed over the at least one light spreading layer, a color conversion layer formed over the partially reflective layer, a collimating layer formed over the color conversion layer, a brightness enhancement film formed over the collimating layer, and a diffuser formed over the brightness enhancement film. The at least one light spreading layer may include two light spreading layers with elongated protrusions that are rotated relative to each other.

Abstract: A construct that supports cell attachment and alignment including a substrate that is incompatible with photolithography conditions, containing a physical pattern in at least part of one surface, the physical pattern optionally bearing a coating of a metal alkoxide, oxide or mixed oxide-alkoxide thereon and a Self-Assembled Monolayer of Phosphonate (SAMP) covalently attached thereto, which phosphonate contains functionality adapted for cell binding. The construct optionally also contains cells attached thereto. Also disclosed are methods of preparing such a construct.

Abstract: An electronic device may have electrical components mounted in an interior region of the electronic device. A housing may surround the interior region and may separate the interior region from an exterior region that surrounds the electronic device. Arrays of recesses may be formed on opposing inner and outer sides of the housing. The arrays may be laterally offset from each other along the housing. The recesses on the inner and outer sides of the housing may meet at passageways within the housing. During operation of the electronic device, air may flow through the inner recesses, the passageways, and the outer recesses to cool electrical components within the interior region. Lighting may be provided for the housing. Light-emitting devices such as light-emitting diodes may be received within cavities in the housing. Light guiding structures, diffusers, reflectors, and other structures may be used to help adjust illumination from the light-emitting devices.

Abstract: A display may have a pixel array such as a liquid crystal pixel array. The pixel array may be illuminated with backlight illumination from a backlight unit. The backlight unit may include a printed circuit board, a plurality of light-emitting diodes mounted on the printed circuit board, at least one light spreading layer formed over the printed circuit board that spreads light received from the plurality of light-emitting diodes, a partially reflective layer formed over the at least one light spreading layer, a color conversion layer formed over the partially reflective layer, a collimating layer formed over the color conversion layer, a brightness enhancement film formed over the collimating layer, and a diffuser formed over the brightness enhancement film. The at least one light spreading layer may include two light spreading layers with elongated protrusions that are rotated relative to each other.

Abstract: A display may have a pixel array such as a liquid crystal pixel array. The pixel array may be illuminated with backlight illumination from a backlight unit. The backlight unit may include a printed circuit board, a plurality of light-emitting diodes mounted on the printed circuit board, at least one light spreading layer formed over the printed circuit board that spreads light received from the plurality of light-emitting diodes, a partially reflective layer formed over the at least one light spreading layer, a color conversion layer formed over the partially reflective layer, a collimating layer formed over the color conversion layer, a brightness enhancement film formed over the collimating layer, and a diffuser formed over the brightness enhancement film. The at least one light spreading layer may include two light spreading layers with elongated protrusions that are rotated relative to each other.

Abstract: A display may have a pixel array such as a liquid crystal pixel array. The pixel array may be illuminated with backlight illumination from a backlight unit. The backlight unit may include a printed circuit board, a plurality of light-emitting diodes mounted on the printed circuit board, at least one light spreading layer formed over the printed circuit board that spreads light received from the plurality of light-emitting diodes, a partially reflective layer formed over the at least one light spreading layer, a color conversion layer formed over the partially reflective layer, a collimating layer formed over the color conversion layer, a brightness enhancement film formed over the collimating layer, and a diffuser formed over the brightness enhancement film. The at least one light spreading layer may include two light spreading layers with elongated protrusions that are rotated relative to each other.