Organic light emitting diode display and method for driving the same
Disclosed are an organic light emitting diode (OLED) display device and a method for driving the same, which are capable of minimizing required memory capacity and the use rate thereof while achieving an enhancement in display quality through execution of an overdriving (or accelerated driving) in accordance with image information of plural accumulated frames. The OLED display device includes a data modulator for sequentially receiving image data of a current frame from a timing controller, counting a number of accumulations of pixels corresponding to image data having a lower grayscale value than a grayscale value of predetermined reference data, generating modulated image data through application of a weight determined in accordance with the counted accumulation number, and supplying the modulated image data to a data driver.
1. An organic light emitting diode display device comprising: an image display panel comprising a plurality of pixel regions; a data driver for driving data lines of the image display panel; a timing controller for arranging image data input from outside of the organic light emitting diode display device to match a size of the image display panel, and generating a data control signal to control the data driver; and a data modulator for sequentially receiving image data of a current frame from the timing controller, counting a number of accumulations of pixels corresponding to image data at a particular position having a lower grayscale value than a grayscale value of predetermined reference data, generating modulated image data through application of a weight value determined in accordance with the counted accumulation number, and supplying the modulated image data to the data driver, wherein the data modulator includes a weight controller for comparing the image data supplied from the timing controller with the predetermined reference data in units of at least one pixel, wherein the comparison is of only the pixels at the particular position, counting an input number of low-grayscale image data having a lower grayscale value than the grayscale value of the predetermined reference data, and outputting the weight value set to correspond to the counted number on a per pixel basis.
2. The organic light emitting diode display device according to claim 1 , wherein the data modulator further comprises:
a look-up table for comparing the image data supplied from the timing controller with image data of a previous frame, and outputting a compensation value corresponding to a difference between the image data from the timing controller and the image data of the previous frame in units of at least one pixel;
a multiplier for multiplying compensation values sequentially output from the look-up table by corresponding ones of the weight value output from the weight controller, thereby sequentially outputting weight data; and
an adder for sequentially adding the weight data sequentially output from the multiplier to the image data of the current frame, to modulate the image data of the current frame, and supplying the modulated image data to the data driver.
3. The organic light emitting diode display device according to claim 2 , wherein the weight controller compares the image data of the current frame with the predetermined reference data in units of at least one of one pixel, a pixel block having “n×m” pixels, pixels at a predetermined position, and a predetermined particular pattern, counts a number of accumulations of low-grayscale image data having a lower grayscale value than the grayscale value of the predetermined reference data, and outputs the weight value corresponding to the counted number on a per pixel basis.
4. The organic light emitting diode display device according to claim 3 , wherein:
when the accumulation number of the image data having a lower grayscale value than the grayscale value of the predetermined reference data is increased, the weight value is set to have predetermined increments according to the increased accumulation number, for application of a high degree of overdriving compensation; and
when the accumulation number of low-grayscale image data is decreased or there is no accumulation of low-grayscale image data, the weight value is set to be maintained or to have predetermined decrements, for application of a low degree of overdriving compensation.
5. A method for driving an organic light emitting diode display device, comprising: driving data lines of an image display panel including a plurality of pixel regions; arranging image data input from outside of the organic light emitting diode display device to match a size of the image display panel, and generating a data control signal to control a data driver; and sequentially receiving image data of a current frame, counting a number of accumulations of pixels corresponding to image data at a particular position having a lower grayscale value than a grayscale value of predetermined reference data, generating modulated image data through application of a weight value determined in accordance with the counted accumulation number, and supplying the modulated image data to the data driver, wherein generating the modulated image data comprises comparing the image data of the current frame at the particular position with the predetermined reference data, wherein the comparing is of only the pixels at the particular position, counting an input number of low-grayscale image data having a lower grayscale value than the grayscale value of the predetermined reference data, and outputting the weight value to correspond to the counted number on a per pixel basis.
6. The method according to claim 5 , wherein the modulated image data further comprises:
comparing the image data of the current frame with image data of a previous frame, and outputting a compensation value corresponding to a difference between the image data of the current frame and the image data of the previous frame in units of at least one pixel;
multiplying sequentially-output compensation values by corresponding ones of the weight value output on a per pixel basis, thereby sequentially outputting weight data; and
sequentially adding the sequentially-output weight data to the image data of the current frame, to modulate the image data of the current frame, and supplying the modulated image data to the data driver.
7. The method according to claim 6 , wherein the outputting the weight value on a per pixel basis comprises:
comparing the image data of the current frame with the predetermined reference data in units of at least one of one pixel, a pixel block having “n×m” pixels, pixels at a predetermined position, and a predetermined particular pattern, and counting a number of accumulations of low-grayscale image data having a lower grayscale value than the grayscale value of the predetermined reference data; and
outputting the weight value corresponding to the counted number on a per pixel basis.
8. The method according to claim 7 , wherein:
when the accumulation number of the image data having a lower grayscale value than the grayscale value of the predetermined reference data is increased, the weight value is set to have predetermined increments according to the increased accumulation number, for application of a high degree of overdriving compensation; and
when the accumulation number of low-grayscale image data is decreased or there is no accumulation of low-grayscale image data, the weight value is set to be maintained or to have predetermined decrements, for application of a low degree of overdriving compensation.