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: 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: Systems and methods are provided to perform refresh-rate dependent dithering. One embodiment describes a computing device that includes an image source that generates spatially dithered image data and an electronic display communicatively coupled to the image source. More specifically, the electronic display receives the spatially dithered image data from the image source and determines a refresh rate with which to display an image by comparing a local histogram and an artifact histogram, in which the local histogram describes pixel grayscale distribution of a portion of the image and the artifact histogram describes a pixel grayscale distribution that when displayed will cause a perceivable artifact. Additionally, when the determined refresh rate is less than a threshold refresh rate of the electronic device, the electronic display spatially dithers the image data without temporally dithering the image data and displays the image based at least in part on the spatially dithered image data.

Abstract: Systems and methods for controlling operation of an electronic display are provided. One embodiment describes an electronic display, which includes a display driver that writes image frames to pixels of the electronic display with a first refresh rate or a second refresh rate; and a timing controller that receives a plurality of image frames from an image source, in which the plurality of image frames are displayed on the electronic display to play video content; detects a cadence with which the plurality of image frames are received from the image source; and, based at least in part on the cadence of the plurality of image frames, instructs the display driver to write each of the plurality of image frames either as a single image frame at the first refresh rate or an image frame at the first refresh rate followed by a repeat of the image frame at the second refresh rate.

Abstract: Devices and methods for reducing or eliminating spatiotemporal dithering image artifacts are provided. By way of example, a method includes providing positive polarity and negative polarity data signals to a plurality of pixels of a display during a first frame period, in which the first frame period corresponds a first spatiotemporal rotation phase. The method includes providing the positive polarity signals and the negative polarity signals to the plurality of pixels of the display during a second frame period, in which the second frame period corresponds a second spatiotemporal rotation phase. A spatiotemporal rotation phase sequence provided to the display comprises the first spatiotemporal rotation phase and the second spatiotemporal rotation phase. One of the first spatiotemporal rotation phase and the second spatiotemporal rotation phase of the spatiotemporal rotation phase sequence is altered during the first frame period or the second time period.

Abstract: One embodiment of the present disclosure describes an electronic display. The electronic display includes a display driver that write image frames to pixels of the electronic display with a first refresh rate or a second refresh rate, in which the second refresh rate is less than the first refresh rate. Additionally, the electronic display includes a timing controller that receives image frames from an image source, in which one or more of the image frames are configured to be displayed on the display panel to play video content; determines a capture rate of the video content based at least in part on a cadence with which the image frames are received, in which the capture rate describes a rate at which each of the one or more image frames was captured by an image sensor; and instructs the display driver to write the one or more of the image frames at the second refresh when the second refresh rate is an integer multiple of the capture rate.

Abstract: Systems, methods, and device are provided to perform refresh-rate dependent dithering. One embodiment of the present disclosure describes a computing device that includes an image source that generates spatially dithered image data and an electronic display communicatively coupled to the image source. More specifically, the electronic display receives the spatially dithered image data from the image source and determines a refresh rate with which to display an image by comparing a local histogram and an artifact histogram, in which the local histogram describes pixel grayscale distribution of a portion of the image and the artifact histogram describes a pixel grayscale distribution that when displayed will cause a perceivable artifact.

Abstract: System and method for improving displayed image quality of an electronic display that displays a first image frame by applying a first voltage to a display pixel and a second image frame directly before the first image frame by applying a second voltage to the display pixel. A display pipeline is communicatively coupled to the electronic display and receives first image data corresponding with the first image frame, where the image data includes a first grayscale value corresponding with the display pixel. Additionally the display pipeline determines an inversion balancing grayscale offset based at least in part on the first grayscale value when polarity of the first voltage and polarity of the second voltage are the same and determines magnitude of the first voltage by applying the inversion balancing grayscale offset to the first grayscale value to reduce likelihood of a perceivable luminance spike when displaying the first image frame.

Abstract: The disclosure describes procedures for dynamically employing a variable refresh rate at an LCD display of a consumer electronic device, such as a laptop computer, a tablet computer, a mobile phone, or a music player device. In some configurations, the consumer electronic device can include a host system portion, having one or more processors and a display system portion, having a timing controller, a buffer circuit, a display driver, and a display panel. The display system can receive image data and image control data from a GPU of the host system, evaluate the received image control data to determine a reduced refresh rate (RRR) for employing at the display panel, and then transition to the RRR, whenever practicable, to conserve power. In some scenarios, the transition to the RRR can be a transition from a LRR of 50 hertz or above to a RRR of 40 hertz or below.

Abstract: Systems and methods for operating a display by dynamically determining a refresh rate for the display. In certain implementations, a processor determines a number of pixels having medium grayscale levels from a histogram for the image. If the number does not exceed a threshold, the processor sets a refresh rate for the display to a first refresh rate. In certain implementations, if the number exceeds a threshold, the processor may set the refresh rate for the display to a second refresh rate. Moreover, the first refresh rate may be lower than the second threshold. In some implementations, the image may be analyzed by subdividing the image into blocks and determining a refresh rate based on grayscale levels or distributions in the blocks. Based on the analysis of the blocks, a corresponding refresh rate may be selected.

Abstract: Systems, apparatuses, and methods for synchronizing backlight adjustments to frame updates in a display pipeline. A change in the ambient light is detected and as a result, backlight settings are adjusted. To offset a reduction in the backlight, the color intensity in the frames is increased. While the change in ambient light is detected asynchronously, the adjustment to the backlight settings and color intensity is synchronized to a frame update via a virtual channel for the auxiliary channel of the display interface.

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: This paper describes various embodiments that relate to personal computer systems, and accurate initialization of computer hardware of personal computer systems from a low-power and/or power-off state. According to one embodiment of the invention, a computer system includes a device operative to be powered down to the power-off state dependent upon an amount of user activity on the computer system. The computer system also includes a device controller operative to initialize the device from the power-off state to a power-on state responsive to user activity on the computer system. The device controller has at least one sensor device operative to determining a physical variable related to the device, and operating characteristics of the device are related to the physical variable.

Abstract: A method is provided for compensating for brightness change in a display. The method includes storing a plurality of look-up tables (LUTs), where each table has a plurality of pixel levels at a variable refresh rate (VRR) and a plurality of brightness signals that provide compensation for the brightness change when refresh rate is changed during a panel self-refresh (PSR). The method also includes receiving an input signal from a graphics processing unit (GPU) and determining the VRR of the input signal from the GPU. The method further includes obtaining the LUT at the determined VRR of the input signal and adjusting the input signal to produce an output signal that compensates for the brightness change for each pixel or sub-pixel in a timing controller based upon the LUT at the determined VRR. The method further includes transmitting the output signal to the display. A system is also provided.

Abstract: A method is provided for compensating for brightness change in a display. The method includes storing a plurality of look-up tables (LUTs), where each table has a plurality of pixel levels at a variable refresh rate (VRR) and a plurality of brightness signals that provide compensation for the brightness change when refresh rate is changed during a panel self-refresh (PSR). The method also includes receiving an input signal from a graphics processing unit (GPU) and determining the VRR of the input signal from the GPU. The method further includes obtaining the LUT at the determined VRR of the input signal and adjusting the input signal to produce an output signal that compensates for the brightness change for each pixel or sub-pixel in a timing controller based upon the LUT at the determined VRR. The method further includes transmitting the output signal to the display. A system is also provided.

Abstract: Systems, methods, and device are provided to perform refresh-rate dependent dithering. One embodiment of the present disclosure describes a computing device that includes an image source that generates spatially dithered image data and an electronic display communicatively coupled to the image source. More specifically, the electronic display receives the spatially dithered image data from the image source and determines a refresh rate with which to display an image by comparing a local histogram and an artifact histogram, in which the local histogram describes pixel grayscale distribution of a portion of the image and the artifact histogram describes a pixel grayscale distribution that when displayed will cause a perceivable artifact.

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: This paper describes various embodiments that relate to personal computer systems, and accurate initialization of computer hardware of personal computer systems from a low-power and/or power-off state. According to one embodiment of the invention, a computer system includes a device operative to be powered down to the power-off state dependent upon an amount of user activity on the computer system. The computer system also includes a device controller operative to initialize the device from the power-off state to a power-on state responsive to user activity on the computer system. The device controller has at least one sensor device operative to determining a physical variable related to the device, and operating characteristics of the device are related to the physical variable.

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 method is provided for compensating for brightness change in a display. The method includes storing a plurality of look-up tables (LUTs), where each table has a plurality of pixel levels at a variable refresh rate (VRR) and a plurality of brightness signals that provide compensation for the brightness change when refresh rate is changed during a panel self-refresh (PSR). The method also includes receiving an input signal from a graphics processing unit (GPU) and determining the VRR of the input signal from the GPU. The method further includes obtaining the LUT at the determined VRR of the input signal and adjusting the input signal to produce an output signal that compensates for the brightness change for each pixel or sub-pixel in a timing controller based upon the LUT at the determined VRR. The method further includes transmitting the output signal to the display. A system is also provided.