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 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 light blocking structures formed from electrochromic material. The electrochromic material may be interposed between first and second electrode layers. When it is desired to operate the display in a private viewing mode, control circuitry may apply a current to the first and second electrodes that causes the electrochromic material to become more opaque, thereby restricting the angle of view of the display. When it is desired to operate the display in a public viewing mode, control circuitry may apply a current to the first and second electrodes that causes the electrochromic material to become more transparent, thereby opening up the angle of view of the display.

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: 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: 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: 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: Liquid crystal display panels and methods of addressing Vcom drift using capacitive measurements as a substitute for direct optical flicker measurements.

Abstract: An electronic device such as a head-mounted device may have displays that are viewable by the eyes of a viewer through adjustable lenses. The adjustable lenses may be liquid crystal lenses. A camera and other sensors in the head-mounted device may monitor the eyes of the user and gather other information. Control circuitry in the head-mounted device may control the adjustable lenses based on measured characteristics of the eyes of the user such as interpupillary distance and direction-of-view. The control circuitry may match the distance between the centers of the adjustable lenses to the measured interpupillary distance and may align the lens centers with the measured direction-of-view. The adjustable lenses may have transparent electrodes that are supplied with time-varying control signals by the control circuitry.

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: An electronic device such as a head-mounted device may have displays that are viewable by the eyes of a viewer through adjustable lenses. The adjustable lenses may be liquid crystal lenses. A camera and other sensors in the head-mounted device may monitor the eyes of the user and gather other information. Control circuitry in the head-mounted device may control the adjustable lenses based on measured characteristics of the eyes of the user such as interpupillary distance and direction-of-view. The control circuitry may match the distance between the centers of the adjustable lenses to the measured interpupillary distance and may align the lens centers with the measured direction-of-view. The adjustable lenses may have transparent electrodes that are supplied with time-varying control signals by the control circuitry.

Abstract: An electronic device such as a head-mounted device may have displays that are viewable by the eyes of a viewer through adjustable lenses. The adjustable lenses may be liquid crystal lenses. A camera and other sensors in the head-mounted device may monitor the eyes of the user and gather other information. Control circuitry in the head-mounted device may control the adjustable lenses based on measured characteristics of the eyes of the user such as interpupillary distance and direction-of-view. The control circuitry may match the distance between the centers of the adjustable lenses to the measured interpupillary distance and may align the lens centers with the measured direction-of-view. The adjustable lenses may have transparent electrodes that are supplied with time-varying control signals by the control circuitry.

Abstract: A liquid crystal display may have main column spacers and subspacer column spacers. The column spacers may have cross shapes formed from overlapping perpendicular rectangular column spacer portions respectively located on a color filter layer and a thin-film transistor layer. The column spacers may have a hybrid configuration in which some of the rectangular portions on the thin-film transistor layer extend vertically and some extend horizontally. Column spacers may be formed from planarization layer material, may be formed from locally thickened portions of a planarization layer, and may have circular shapes.

Abstract: A display may have display layers such as liquid crystal display layers having a liquid crystal layer interposed between a color filter layer and a thin-film transistor layer or organic light-emitting diode layers having organic light-emitting diodes formed from thin-film transistor circuitry. The display layers may be configured to form an array of pixels that display images and may include a polarizer. An angle-of-view adjustment layer may overlap the display layers. The angle-of-view adjustment layer may include one or more liquid crystal layers. A first polarizer may be interposed between first and second liquid crystal layers and the second liquid crystal layer may be overlapped by a second polarizer. The first and second polarizers may have pass axes that are aligned with a pass axis of the polarizer in the display layers. One or more liquid crystal layers in the angle-of-view adjustment layer may include dichroic dye.

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: Systems and methods are provided for improving displayed image quality of an electronic display that includes a display pixel. The electronic display displays a first image frame directly after a second image frame by applying an analog electrical signal to the display pixel. To facilitate display of the first image frame, circuitry receives image data corresponding to the image frame, in which the image data includes a grayscale value that indicates target luminance of the display pixel; determines expected refresh rate of the first image frame based at least in part on actual refresh rate of the second image frame; determines a pixel response correction offset based at least in part on the expected refresh rate of the first image frame; and determines processed image data by applying the pixel response correction offset to the grayscale value, in which the processed image data indicates magnitude of the analog electrical signal.

Abstract: Liquid crystal display systems and methods of operation are described. In an embodiment, a liquid crystal display pixel cell includes an insulation layer spanning over a passivation layer and the plurality of signal electrodes such that it separates the signal electrodes from polymer alignment layer for the liquid crystal. In an embodiment, a method of operating a liquid crystal display panel includes temporal compensation of the Vcom value as a function of time and one or more operating parameters.

Abstract: An electronic device may have a display. Input-output circuitry in the electronic device may be used to gather input from a viewer of the display. The input-output circuitry may include a gaze tracking system that gathers point-of-gaze information, vergence information, and head position information, may be a biometric sensor, may be an input device such as a button or touch sensor, may capture hand gestures, and/or may gather other information. The display may include a pixel array for producing images. An adjustable reflectance and transmittance layer may overlap the pixel array. Control circuitry in the electronic device may individually adjust different areas of the adjustable reflectance and transmittance layer. The control circuitry may place each area in a reflective mirror more or in a content-displaying mode and may move the areas in response to the information.

Abstract: An electronic device may generate content that is to be displayed on a display. The display may have an array of liquid crystal display pixels for displaying image frames of the content. The display may be operated in at least a normal viewing mode, a privacy mode, an outdoor viewing mode, and a power saving mode. The different view modes may exhibit different viewing angles. In one configuration, the display may include a switchable phase retarder that can be selectively activated to help reduce contrast ratios at higher viewing angles. A rotated pixel design that includes one or more groups of parallel fingers can be used to help properly align the low contrast regions. In another configuration, the display may include multiple electrically controlled birefringence (ECB) layers that can be selectively activated to provide a desired cone of vision, a region outside of which exhibits substantially reduced contrast ratios.