Organic light emitting diode display for compensating image data and method of driving the same
An organic light emitting diode (OLED) display device and a method of driving the same are discussed. The method includes sensing a threshold voltage and mobility of a driving thin film transistor (TFT) included in each pixel using a sensing line connected per pixel and supplying the threshold voltage and the mobility to a timing controller in a measurement mode, by a data driver, and supplying image data input from an external source to the data driver by a timing controller, the timing controller adding and multiplying an offset value and gain value corresponding to the threshold voltage and mobility of the driving TFT, sensed by the data driver in the measurement mode, with the image data to compensate the image data, wherein the compensation of the image data includes varying a weight of the gain value according to luminance of the image data.
1. An organic light emitting diode (OLED) display device comprising:
a display panel comprising a plurality of pixels, each comprising a light emitting device and a driving thin film transistor (TFT) for supplying driving current to the light emitting device;
a gate driver for driving gate lines connected to each pixel;
a data driver for sensing a threshold voltage and a mobility of the driving TFT using a sensing line connected to each pixel in a measurement mode, and applying a data voltage to data lines connected to each pixel in a display mode; and
a timing controller for sorting image data input from an external source and supplying the image data to the data driver in the display mode,
wherein the timing controller comprises:
an average picture level (APL) detector for analyzing the image data input thereto on a frame basis to calculate an APL;
a peak luminance controller for controlling a peak luminance per frame according to the APL provided from the APL detector; and
a data compensator for calculating an offset value and a gain value from the threshold voltage and the mobility of the driving TFT, supplied from the data driver, multiplying the image data and the calculated gain value and then adding the calculated offset value to a result value to compensate the image data, and varying a weight of the gain value according to the APL supplied from the APL detector while the image data is multiplied by the gain value, in the measurement mode, and
wherein:
the peak luminance controller sets the peak luminance to a maximum luminance when the APL is 0 to a reference level and sets the peak luminance to decrease down to a minimum luminance from the maximum luminance when the APL is the reference level to 1; and
the data compensator sets the weight of the gain value to a first percentage of a maximum gain value or less when the APL is 0 to the reference level, and sets the weight of the gain value to increase to the maximum gain value from the first percentage of the maximum gain value when the APL is the reference level to 1.
2. The OLED display device according to claim 1 , wherein the weight of the gain value has an inclination that gradually increases when the APL is the reference level to 1.
3. The OLED display device according to claim 1 , wherein the weight of the gain value has an inclination that gradually decreases when the APL is the reference level to 1.
4. The OLED display device according to claim 1 , wherein the weight of the gain value linearly increases when the APL is the reference level to 1.
5. A method of driving an organic light emitting diode (OLED) display device, the method comprising:
sensing a threshold voltage and a mobility of a driving thin film transistor (TFT) included in each pixel using a sensing line connected per pixel and supplying the threshold voltage and the mobility to a timing controller in a measurement mode, by a data driver;
supplying image data input from an external source to the data driver by the timing controller;
analyzing the image data input thereto on a frame basis to calculate an average picture level (APL);
controlling a peak luminance per frame according to the APL; and
calculating an offset value and a gain value from the threshold voltage and the mobility of the driving TFT, supplied from the data driver, multiplying the image data and the calculated gain value and then adding the calculated offset value to a result value to compensate the image data, and varying a weight of the gain value according to the APL while the image data is multiplied by the gain value, in the measurement mode,
wherein:
the controlling of the peak luminance comprises setting the peak luminance to a maximum luminance when the APL is 0 to a reference level, and setting the peak luminance to decrease down to a minimum luminance from the maximum luminance when the APL is the reference level to 1; and
the varying of the weight of the gain value comprises setting the weight of the gain value to a first percentage of a maximum gain value or less when the APL is 0 to the reference level, and setting the weight of the gain value to increase to the maximum gain value from the first percentage of the maximum gain value when the APL is the reference level to 1.