Abstract: A display may have a first stage such as a color liquid crystal display stage and a second stage such as a monochromatic liquid crystal display stage that are coupled in tandem so that light from a backlight passes through both stages. The dynamic range of the display may be enhanced by using the second stage to perform local dimming operations. The pixel pitch of the second stage may be greater than the pixel pitch of the first stage to ease alignment tolerances and reduce image processing complexity. The color stage and monochromatic stages may share a polarizer. A color filter in the color stage may have an array of red, green, and blue elements or an array of white, red, green, and blue elements. The color stage may be a fringe field display and the monochrome stage may be an in-plane switching display or a twisted nematic stage.

Abstract: An electronic device may have a display such as a liquid crystal display. The display may have an array of pixels that display images to a user. Backlight structures may provide the array of pixels with backlight illumination at a backlight illumination level. The backlight structures may have a light source with an array of light-emitting diodes and photoluminescent material that is pumped by pump light from the light-emitting diodes. The backlight illumination may experience color variations as a function of the backlight illumination level. Circuitry in the electronic device may be used to implement a backlight level color compensator. The backlight level color compensator may apply color correction factors to the image data of the displayed images to compensate for variations in color of the image data due to variations in backlight illumination level and operating temperature.

Abstract: The invention relates to methods for the preparation of high purity Bivalirudin. The polypeptide is prepared in a high purity of at least 98.5% (by HPLC), wherein the total impurities amount to less than 1.5%, comprising not more than 0.5% [Asp9-Bivalirudin] and each is impurity less than 1.0%, and preferably having a purity of at least about 99.0% by HPLC, wherein the total impurities amount to less than 1.0%, comprising not more than 0.5% [Asp9-Bivalirudin] and each impurity is less than 0.5%.

Abstract: An electronic device may include a display having an array of display pixels. Storage and processing circuitry may generate display data for the display in an RGB input color space. The display may display the display data in an RGBW output color space. Display control circuitry may use sets of predetermined conversion factors to convert display data from the RGB input color space to the RGBW output color space without requiring conversion to a device-independent color space. Each set of predetermined conversion factors may be associated with a color in a set of predetermined colors. Using the sets of predetermined conversion factors, the display control circuitry may convert RGB values in the input color space to RGBW values in the output color space. The display control circuitry may supply data signals corresponding to the display data in the RGBW output color space to the array of display pixels.

Abstract: An electronic device may include a display having an array of display pixels and having display control circuitry that controls the operation of the display. The display control circuitry may adaptively adjust the display output based on ambient lighting conditions. For example, in cooler ambient lighting conditions such as those dominated by daylight, the display may display neutral colors using a relatively cool white. When the display is operated in warmer ambient lighting conditions such as those dominated by indoor light sources, the display may display neutral colors using a relatively warm white. Adapting to the ambient lighting conditions may ensure that the user does not perceive color shifts on the display as the user's vision chromatically adapts to different ambient lighting conditions. Adaptively adjusting images in this way can also have beneficial effects on the human circadian rhythm by displaying warmer colors in the evening.

Abstract: A display may store extended display identification data for communicating the capabilities of the display to a source device such as a graphics processing unit. The extended display identification data may include a red primary color value, a green primary color value, and a blue primary color value. The primary color values in the extended display identification data may be determined during manufacturing. For example, a light sensor may measure the native primary colors of the display, and calibration computing equipment may determine if the native primary colors of the display are within a target color gamut. If the native primary colors of the display are outside of the target color gamut by an amount larger than a threshold, the primary color values in the extended display identification data may be adjusted to account for the color variation.

Abstract: Methods and apparatuses to varying the apparent brightness of a display are described. The change in apparent brightness is accompanied by unchanged in relative contrast, rendering a display with higher or lower brightness while maintaining contrast fidelity. In exemplary embodiments, the signals for the middle tone levels are adjusted to increase or decrease the brightness intensity, while keeping constant the gamma correction. This maintains the relative contrast of images while rendering them at a different brightness. Implementations of the present process include an adjusted gamma correction lookup table, incorporated in the video card to modify the video signal before reaching the display. The present invention can be used for matching the brightness of two or more displays or to provide compensation for variations in display characteristics to ensure consistency in display brightness within a data processing model.

Abstract: Systems and methods for reducing or eliminating image artifacts on a dual-layer liquid crystal display (LCD). By way of example, a system includes a first display panel and a second display panel. The system includes a processor coupled to the first display panel and the second display panel, and configured to generate a first image, and to generate a second image to be displayed on the first display panel based on the first image. The processor is configured to interpolate the second image. Interpolating the second image includes adjusting the second image according to a generated objective function bounded by a first constraint. The processor is configured to filter the second image, and to generate a third image to be displayed on the second display panel based on the first image and the second image. The third image is generated to prevent image artifacts on the second display panel.

Abstract: An electronic device may include a display having an array of display pixels and having display control circuitry that controls the operation of the display. The display control circuitry may adaptively adjust the display output based on ambient lighting conditions. For example, in cooler ambient lighting conditions such as those dominated by daylight, the display may display neutral colors using a relatively cool white. When the display is operated in warmer ambient lighting conditions such as those dominated by indoor light sources, the display may display neutral colors using a relatively warm white. Adapting to the ambient lighting conditions may ensure that the user does not perceive color shifts on the display as the user's vision chromatically adapts to different ambient lighting conditions. Adaptively adjusting images in this way can also have beneficial effects on the human circadian rhythm by displaying warmer colors in the evening.

Abstract: An electronic device may include a display and display control circuitry. The display may be calibrated to compensate for changes in display temperature. Display calibration information may be obtained during manufacturing and may be stored in the electronic device. The display calibration information may include adjustment factors configured to adjust incoming pixel values to reduce temperature-related color shifts. During operation of the electronic device, display control circuitry may determine the temperature at different locations on the display. The display control circuitry may determine the temperature at a given display pixel using the temperatures at the different locations on the display. The display control circuitry may determine adjustment values based on the temperature at the display pixel. The display control circuitry may apply the adjustment values to incoming pixel values to obtain adapted pixel values, which may in turn be provided to the display pixel.

Abstract: An electronic device may include a display having an array of display pixels. The display pixels may include red, green, blue, and white subpixels. Pixel mapping circuitry may convert red-green-blue pixel values in a frame of display data to red-green-blue-white pixel values using a brightness adjustment factor. The brightness adjustment factor may be determined based on ambient lighting conditions. The brightness adjustment factor be determined such that any color distortion resulting from applying the brightness adjustment factor is maintained under a just-noticeable-difference (JND) threshold. White subpixel values may be determined based on the brightness adjustment factor. Pixel rendering circuitry may be used to render red-green-blue-white pixel values onto the physical pixel structure. When a display pixel does not include a subpixel of a particular color, the pixel rendering circuitry may compensate for the missing color using nearby subpixels.

Abstract: A method and user interface for direct setting of black and white points. Black point is set using a slider and matching of gray shades. White point setting is performed by having a setting object move within a defined region, such as a square or circle, with the area where the setting object moves being adjusted dynamically based on the location of the setting object with respect to the defined region. When the area is the desired white, the setting is complete. Preferably the defined region has a varying color border to allow a reference for the user in moving the setting object. A more detailed setting of gray levels can be accomplished by providing a gray scale with reference points. Each reference point has an associated white point setting area, so that settings are developed for each reference point. Settings at other locations are determined by interpolation or extrapolation.

Abstract: A display may have a first stage such as a color liquid crystal display stage and a second stage such as a monochromatic liquid crystal display stage that are coupled in tandem so that light from a backlight passes through both stages. The dynamic range of the display may be enhanced by using the second stage to perform local dimming operations. The pixel pitch of the second stage may be greater than the pixel pitch of the first stage to ease alignment tolerances and reduce image processing complexity. The color stage and monochromatic stages may share a polarizer. A color filter in the color stage may have an array of red, green, and blue elements or an array of white, red, green, and blue elements. The color stage may be a fringe field display and the monochrome stage may be an in-plane switching display or a twisted nematic stage.

Abstract: An optical test equipment/method for display testing that features parallel testing/sensing configuration that covers spectrum and colorimetric quantities with spatial resolution is disclosed. In one embodiment, a spectra-camera, which is a hybrid system consisting of both a single-point spectrometer and an imaging colorimeter, can be configured for concurrent display artifact and parametric testing. An aperture mirror with a hole in the middle splits an image of a test display into two parts. One part of the image passes through the hole and is directed to the spectrometer for display parametric testing. The rest of the image is reflected off the aperture mirror for concurrent display artifact testing with the colorimeter. In another embodiment, a beam splitter can be used instead of an aperture mirror. In yet another embodiment, the single-point high accuracy spectrometer can be used to calibrate the low accuracy imaging colorimeter.

Abstract: A calibration system may be provided for calibrating displays in electronic devices during manufacturing. The calibration system may include calibration computing equipment and a test chamber having a light sensor. The calibration computing equipment may be configured to operate the light sensor and the display to gather display performance data. The calibration computing equipment may extract display performance statistics from the display performance data and adaptively select and perform display calibration sequences using the display performance statistics. The calibration computing equipment may be configured to determine whether or not to perform display calibration and whether or not to gather additional display performance data based on display performance statistics extracted during a preceding display calibration sequence. The calibration computing equipment may be configured to iteratively and adaptively perform display calibration sequences until a display is successfully calibrated.

Abstract: A method is provided for calibrating a display having color channels. Each color channel is capable of adjusting settings for pixel values at gray level entries. The method includes selecting a gray level entry for calibration. The method also includes providing a target white point in chromaticity coordinates (x, y) and a target brightness at the selected gray level entry to the display. The method further includes adjusting the setting for the pixel values for the color channels at the selected gray level entry such that the display achieves the target white point and the target brightness at an adjusted pixel value.

Abstract: An electronic device may include a display and display control circuitry. The display may be calibrated to compensate for changes in display temperature. Display calibration information may be obtained during manufacturing and may be stored in the electronic device. The display calibration information may include color-specific adjustment factors configured to adjust display colors and reduce temperature-related color shifts. During operation of the display, the display control circuitry may receive input pixel values for a display pixel. The display control circuitry may also receive display temperature information from a temperature sensor in the electronic device. The display control circuitry may determine adjustment factors based on a color associated with the input pixel values and the display temperature information. The display control circuitry may apply the adjustment factors to the input pixel values to obtain adapted pixel values. The adapted pixel values may be provided to the display pixel.

Abstract: An electronic device may include a display having an array of display pixels. Storage and processing circuitry may generate display data for the display in an RGB input color space. The display may display the display data in an RGBW output color space. Display control circuitry may use sets of predetermined conversion factors to convert display data from the RGB input color space to the RGBW output color space without requiring conversion to a device-independent color space. Each set of predetermined conversion factors may be associated with a color in a set of predetermined colors. Using the sets of predetermined conversion factors, the display control circuitry may convert RGB values in the input color space to RGBW values in the output color space. The display control circuitry may supply data signals corresponding to the display data in the RGBW output color space to the array of display pixels.

Abstract: A calibration system may be provided for calibrating displays in electronic devices during manufacturing. The calibration system may include calibration computing equipment and a test chamber having a light sensor. The calibration computing equipment may be configured to operate the light sensor and the display to gather display intensity performance data for obtaining a display gamma model. The display intensity performance data may be gathered using a range of display control settings that will be used in performing color calibration operations for the display. The calibration computing equipment may be configured to operate the light sensor and the display to gather display color performance data for determining a display white point calibration. Display white point calibration data may be provided to the electronic device and stored in volatile or non-volatile memory in the device or may be permanently stored in circuitry associated with the display.

Abstract: Methods and apparatuses to varying the apparent brightness of a display are described. The change in apparent brightness is accompanied by unchanged in relative contrast, rendering a display with higher or lower brightness while maintaining contrast fidelity. In exemplary embodiments, the signals for the middle tone levels are adjusted to increase or decrease the brightness intensity, while keeping constant the gamma correction. This maintains the relative contrast of images while rendering them at a different brightness. Implementations of the present process include an adjusted gamma correction lookup table, incorporated in the video card to modify the video signal before reaching the display. The present invention can be used for matching the brightness of two or more displays or to provide compensation for variations in display characteristics to ensure consistency in display brightness within a data processing model.