Abstract: An electronic device may have a display with an array of inorganic light-emitting diodes. The array of inorganic light-emitting diodes may be overlapped by a polarizer layer such as a circular polarizer. Alternatively, the display may be a polarizer-free display without any polarizer layer over the array of inorganic light-emitting diodes. Each inorganic light-emitting diode may be surrounded by a diffuser that redirects edge-emissions towards a viewer. A top diffuser, a color filter layer, a microlens, and/or a microlens with color filtering and/or diffusive properties may also optionally overlap each inorganic light-emitting diode. The inorganic light-emitting diodes may have reflective sidewalls to mitigate edge-emissions. In this type of arrangement, the array of inorganic light-emitting diodes may be coplanar with one or more opaque masking layers. To mitigate reflections, the display may include two opaque masking layers having differing properties or a single phase separated opaque masking layer.

Abstract: Increasing resolution of liquid crystal displays may result in small distances between adjacent liquid crystal display pixels. This tight pixel spacing may reduce transmission through the liquid crystal display pixels and may result in cross-talk between the liquid crystal display pixels. To increase transmission and, correspondingly, display efficiency, a reflective layer may be included in the liquid crystal display. The reflective layer recycles backlight that may otherwise be absorbed, improving transmittance and efficiency. To reduce color shift and color mixing caused by cross-talk, the pixels may have their pixel electrodes arranged in a zigzag layout. Each pixel electrode may have a height that is less than or equal to the total height of the pixel divided by two. The pixel electrodes in a given row are also alternatingly coupled to first and second gate lines. This zigzag layout results in an increased distance between adjacent pixel electrodes, mitigating pixel cross-talk.

Abstract: A system may have windows. The window may have first and second window layers and a layer of material such as guest-host liquid crystal material between the first and second window layers. Electrodes on the window layers may be used to apply electric fields to the guest-host liquid crystal material to adjust the light transmission properties of the window. To ensure that a desired gap between the first and second window layers is maintained, spacers may be formed between the first and second window layers. The spacers may include key-and-lock spacers that have interlocking portions located, respectively, on the first and second window layers. Spacers such as photoresist posts can be attached using adhesive. Hybrid arrangements may also be used in which key-and-lock spacer structures are attached using adhesive bonds.

Abstract: A system such as a vehicle, building, or electronic device system may have a support structure with one or more windows. The support structure and window may separate an interior region within the system from a surrounding exterior region. Control circuitry may receive input such as user input and may adjust an adjustable layer in the window based on the input. The adjustable layer may have a polymer matrix layer with embedded cells. The cells may include intermixed guest-host liquid crystal cells and liquid crystal cells. The guest-host liquid crystal cells and liquid crystal cells may have different liquid crystal materials and/or different sizes that allow the guest-host liquid crystal cells and liquid crystal cells to electrically switch states at different respective threshold voltages. Based on the user input or other input the control circuitry can adjust a drive signal across the adjustable layer to change light transmittance and haze.

Abstract: An optical system is described. The optical system may include a sensor which may be in a mobile device. The optical system may use the same light source for imaging the display and for providing light to a sensor or sensor device. The optical system may be configured so that randomly polarized light will exit the device for viewing so that a user may view the display in any rotated orientation while wearing polarized eyewear. The optical system may further be configured to mitigate reflections in the mobile device from ambient light entering the system and from reflected and backscattered light from cross-contaminating the imaging light of the display.

Abstract: A system such as a vehicle, building, or electronic device system may have a support structure with one or more windows. The support structure and window may separate an interior region within the system from a surrounding exterior region. Control circuitry may receive input such as user input and may adjust an adjustable layer in the window based on the input. The adjustable layer may have a polymer matrix layer with embedded cells. The cells may include intermixed guest-host liquid crystal cells and liquid crystal cells. The guest-host liquid crystal cells and liquid crystal cells may have different liquid crystal materials and/or different sizes that allow the guest-host liquid crystal cells and liquid crystal cells to electrically switch states at different respective threshold voltages. Based on the user input or other input the control circuitry can adjust a drive signal across the adjustable layer to change light transmittance and haze.

Abstract: Certain embodiments are directed to techniques (e.g., a method, an apparatus, and non-transitory computer readable medium storing code or instructions executable by one or more processors) for mitigating the flicker on the displays at low driving frequencies due to drops of the voltage holding ratio of the materials for the display. The techniques to compensate for flicker in a liquid crystal display can include generating a dynamic waveform for the backlight of the display. The dynamic waveform can be synchronized with the driving rate of the liquid crystal display such that the luminosity of the backlight increases during periods when the voltage-holding ratio drops in the materials of the display. In this way, a liquid crystal material can be utilized in a display to generate reduced power consumption with liquid crystal rate minimizing the flicker in response to the drops of the voltage-holding ratio.

Abstract: A display may have display layers that form an array of pixels. An angle-of-view adjustment layer may overlap the display layers. The angle-of-view adjustment layer may include an array of adjustable louvers that move from a first position in which the angle of view of the display is restricted for a private viewing mode and a second position in which the angle of view of the display is not restricted for a normal viewing mode. The louvers may contain electrophoretic particles. The louvers may be tapered and may have a width at one end that is less than ten microns. The electrophoretic particles may form isolated clusters on a lower substrate in normal viewing mode to increase the transmittance of the display in normal viewing mode. The angle-of-view adjustment layer may be a second liquid crystal display layer that is used to block off-axis light.

Abstract: An electronic device may have a display such as an organic light-emitting diode display. A compensation film may be used to correct the color shift in the display. The compensation film may include a layer of liquid crystals and dye aligned with the liquid crystals. The dye may be configured to absorb different amounts of light depending on an angle that the light passes through the compensation film. Higher angled light will have a longer path length through the compensation film and therefore more of the higher angled light will be absorbed by the dye. The dye may therefore compensate for the color shift that occurs at high viewing angles.

Abstract: Certain embodiments are directed to techniques (e.g., a method, an apparatus, and non-transitory computer readable medium storing code or instructions executable by one or more processors) for mitigating the flicker on the displays at low driving frequencies due to drops of the voltage holding ratio of the materials for the display. The techniques to compensate for flicker in a liquid crystal display can include generating a dynamic waveform for the backlight of the display. The dynamic waveform can be synchronized with the driving rate of the liquid crystal display such that the luminosity of the backlight increases during periods when the voltage-holding ratio drops in the materials of the display. In this way, a liquid crystal material can be utilized in a display to generate reduced power consumption with liquid crystal rate minimizing the flicker in response to the drops of the voltage-holding ratio.

Abstract: Optical systems may have tunable lenses with focal lengths that are adjusted by control circuitry. A display may produce image light that is received by a tunable lens. The display may be transparent so that light from objects can pass through the display and be received by the tunable lens. The tunable lens may include a birefringent lens element and a polarization rotator and may receive light that has been linearly polarized by passing through a linear polarizer. The polarization rotator may be operable in a first state in which the polarization of light passing through the polarization rotator is not rotated and a second state in which the polarization of light passing through the polarization rotator is rotated by 90°. The birefringent lens element may be formed from a cured liquid crystal polymer or other polymer and may have a liquid crystal additive to enhance birefringence.

Abstract: An electronic device may be provided with a display. An optical component window may be formed in the inactive area of the display. The optical component window may transmit infrared light from an infrared light source. The infrared light source may include a diffuser to allow the light source to operate in a flood illumination mode and a structured light mode. The diffuser may include liquid crystal material between first and second substrates. A sealant may surround the liquid crystal layer, and one or more spacer walls may be located between the sealant and the liquid crystal layer. An additional spacer wall may be used outside of the sealant to prevent metal from creating an electrical short between electrodes in the diffuser. Conductive material in the sealant may be used to couple a top electrode to a metal pad on a bottom substrate.

Abstract: An optical system may include equipment with a housing that is configured to receive external equipment such as a cellular telephone. The external equipment may have a display mounted on a front face of the external equipment and may have additional components such as a front-facing camera. Communications circuitry in the equipment may support wired and wireless communications with the external equipment. An optical combiner in the equipment may be used to combine display image light emitted from pixels in the display with real-world image light received from external objects. The optical combiner may have a reflector with a concave lens shape that focuses light from the display towards eye boxes in which a viewer's eyes are located. The reflector may be a partial mirror or a reflective polarizer. The reflective polarizer and additional components may be used in implementing a tunable tint layer.

Abstract: Aspects of the subject technology relate to gaze-dependent visual encryption of electronic device displays. Each display frame that is displayed on the electronic device display may include a clear-display region around the user's gaze location and an obscured region outside the clear-display region. In this way, only the display content that the user is actively viewing is recognizable and understandable and an onlooker such as an unwanted observer looking over the user's shoulder is unable to understand what is displayed. The obscured region of each display frame may be generated such that the overall look and structure of that region is unchanged, but the content is unintelligible. In this way, the visual experience of the user is not disrupted or distracted by the visual encryption and the eye of the onlooker is not guided to the clear-display region by the visual encryption.

Abstract: An optical system is described. The optical system may include a sensor which may be in a mobile device. The optical system may use the same light source for imaging the display and for providing light to a sensor or sensor device. The optical system may be configured so that randomly polarized light will exit the device for viewing so that a user may view the display in any rotated orientation while wearing polarized eyewear. The optical system may further be configured to mitigate reflections in the mobile device from ambient light entering the system and from reflected and backscattered light from cross-contaminating the imaging light of the display.

Abstract: An optical system may include equipment with a housing that is configured to receive external equipment such as a cellular telephone. The external equipment may include a display. To control the persistence of the display, the optical system may include a light modulating layer. The light modulating layer may switch between a transparent state in which display image light is passed through the light modulating layer to reach the viewer and an opaque state in which display image light is blocked by the light modulating layer from reaching the viewer. The light modulating layer may be placed in the transparent state for a portion of each display frame and the opaque state for the remaining portion of each display frame. The light modulating layer may be formed in the housing of the equipment that receives the external equipment or may be formed with the external equipment directly.

Abstract: Electrical shield line systems are provided for openings in common electrodes near data lines of display and touch screens. Some displays, including touch screens, can include multiple common electrodes (Vcom) that can have openings between individual Vcoms. Some display screens can have an open slit between two adjacent edges of Vcom. Openings in Vcom can allow an electric field to extend from a data line through the Vcom layer. A shield can be disposed over the Vcom opening to help reduce or eliminate an electric field from affecting a pixel material, such as liquid crystal. The shield can be connected to a potential such that electric field is generated substantially between the shield and the data line to reduce or eliminate electric fields reaching the liquid crystal.

Abstract: An electronic device such as a head-mounted device may have a display that displays computer-generated content for a user. The head-mounted device may have an optical system that directs the computer-generated content towards eye boxes for viewing by a user. The optical system may include a spatially addressable adjustable optical component. The adjustable optical component may have first and second electrodes and an electrically adjustable material between the first and second electrodes. The electrically adjustable material may include a transparent conductive material such as indium tin oxide that includes a pattern of segmented trenches configured to provide the transparent conductive material with electrical anisotropy. Contacts may be coupled to the transparent conductive material. Control circuitry can adjust the electrically adjustable material to form a spatially addressable light modulator or adjustable lens.

Abstract: An electronic device may include display layers such as liquid crystal display layers and a backlight unit that provides illumination for the display layers. The backlight unit may include light-emitting diodes that emit light into the edge of a light guide film. To minimize the inactive area of the display, the light-emitting diodes may be tightly spaced to approximate a line light source instead of point light sources. Color and/or luminance compensation layers may be incorporated at various locations within the backlight structures to ensure that the backlight provided to the display layers is homogenous. A thin-film transistor layer of the display may be coupled to a printed circuit board by a flexible printed circuit. The flexible printed circuit may have additional solder mask layers to improve robustness, may include encapsulation, and may have traces with a varying pitch.

Abstract: A window may be provided with a light modulator. The light modulator may be dynamically adjusted to control visible light transmission through the window. The window may also have layers that selectively block light with non-visible wavelengths. The light-blocking layers may block ultraviolet light, near infrared light such as light from solar radiation, and far infrared light such as heat produced due to the absorption of visible light by the light modulator. The light modulator may be a guest-host liquid crystal light modulator. The guest-host liquid crystal light modulator may have a layer of liquid crystal material with dye that is interposed between polymer substrate layers. The polymer substrate layers may be thermoplastic layers that are moldable to conform to window shapes with compound curves.