Method for Grayscale Rendition in Am-Oled
First Claim
1. Method for displaying an image in an active matrix organic light emitting display comprising a plurality of cells, a data signal being applied to each cell for displaying a grayscale level of a pixel of the image during a video frame, wherein the video frame is divided into N consecutive subframes, with N≧
- 2, and in that the data signal of a cell comprises N independent elementary data signals, each of said elementary data signals being applied to the cell during a subframe and the grayscale level displayed by the cell during the video frame depending on the amplitude of the elementary data signals and the duration of the subframes and the duration of the subframes is increasing from the first subframe to the last subframe of the video frame and, for each grey level, the amplitude of the elementary data signals is decreasing from the first subframe to the last subframe of the video frame.
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Abstract
The present invention relates to a grayscale rendition method in an active matrix OLED (Organic Light Emitting Display) where each cell of the display is controlled via an association of several Thin-Film Transistors (TFTs). In order to improve the grayscale rendition in an AM-OLED when displaying low grayscale levels and/or when displaying moving pictures, it is proposed to split each frame into a plurality of subframes wherein the amplitude of the data signal applied to a cell of the AM-OLED can be adapted to conform to the visual response of a CRT display. According to the invention, the video frame used for displaying an image is divided into N consecutive subframes, with N≧2, and the data signal applied to the cell comprises N independent elementary data signals, each of said elementary data signals being applied to the cell during a subframe. The grayscale level displayed by the cell during the video frame is depending on the amplitude of the elementary data signals and the duration of the subframes.
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Citations
13 Claims
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1. Method for displaying an image in an active matrix organic light emitting display comprising a plurality of cells, a data signal being applied to each cell for displaying a grayscale level of a pixel of the image during a video frame, wherein the video frame is divided into N consecutive subframes, with N≧
- 2, and in that the data signal of a cell comprises N independent elementary data signals, each of said elementary data signals being applied to the cell during a subframe and the grayscale level displayed by the cell during the video frame depending on the amplitude of the elementary data signals and the duration of the subframes and the duration of the subframes is increasing from the first subframe to the last subframe of the video frame and, for each grey level, the amplitude of the elementary data signals is decreasing from the first subframe to the last subframe of the video frame.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. Apparatus for displaying an image comprising
an active matrix comprising a plurality of organic light emitting cells, a row driver for selecting line by line the cells of said active matrix a column driver for receiving data signals to be applied to the cells for displaying grayscale levels of pixels of the image during a video frame, and a digital processing unit for generating said data signals and control signals to control the row driver wherein the video frame is divided into N consecutive subframes and the duration of the subframes is increasing from the first subframe to the last subframe of the video frame, with N≧ - 2, and the digital processing unit generates data signal each comprising N independent elementary data signals such that, for each grey level, the amplitude of the elementary data signals is decreasing from the first subframe to the last subframe of the video frame, each of said elementary data signals being applied via the column driver to a cell during a subframe, the grayscale level displayed by the cell during the video frame depending on the amplitude of the elementary data signals and the duration of the subframes.
- View Dependent Claims (12, 13)
Specification