DISPLAY DEVICE
In order to efficiently suppress pseudo contours, a display device has pixels arranged in a matrix arrangement, and performs display by performing digitally driving according to pixel data of an image signal. The driver divides pixel data for a single pixel into corresponding sub-frames as a plurality of bit data, and forms one frame from a specified repeating number of unit frames and digitally drives each pixel by providing the bit data to each pixel. A data analyzing circuit analyzes input data, and analyzes likelihood of occurrence of pseudo contours. A refresh rate control circuit controls the driver based on the analysis results to change a repeating number of unit frames of a single frame.
1 . A method for driving an electroluminescent display, comprising:
(a) providing the electroluminescent (EL) display having a pixel array having a plurality of pixels arranged in a matrix, a plurality of select lines arranged for each line of pixels and a plurality of data lines arranged for each column of pixels, a select driver for selectively driving the select lines, and a data driver for driving the data lines, wherein each pixel includes an organic EL element and a drive transistor for causing current to flow into the organic EL element to cause it to emit light;
(b) receiving an image having input data for each pixel;
(c) dividing the input data for each pixel into a plurality of bit data values for a plurality of sub-frames, respectively);
(d) analyzing the input data for the image to detect critical transition (CT) pixels for which pseudo contours occur with line of sight movement;
(e) selecting a refresh rate based on the detected critical transition pixels; and
(f) providing the bit data of the plurality of sub-frames sequentially to the respective pixels during one or more unit frame period(s) to cause the pixel array to display images at the selected refresh rate, wherein the unit frame period(s) corresponds to the refresh rate).
2 . The method of claim 1 , wherein step (d) further includes calculating a level of CT pixels by dividing the number of detected CT pixels by the number of pixels in the plurality of pixels, and wherein step e further includes increasing the refresh rate when the level of CT pixels exceeds a selected percentage).
3 . The method of claim 1 , wherein step (d) includes
(i) performing an OR or exclusive-or (XOR) operation on the respective bit data values of a selected first pixel and a selected second pixel peripheral to the first pixel; and
(ii) comparing the result of the OR or XOR operation to the respective bit data values of the selected first pixel and selected second pixel, and detecting a CT pixel if the result of the OR or XOR operation has greater than a selected difference from the respective bit data values of the selected first pixel and selected second pixel.
4 . The display device of claim 1 , wherein each pixel includes a plurality of sub-pixels, and respective different bit data values of the pixel are provided to each sub-pixel during each sub-frame.