EL display device for reducing pseudo contour
View Patent ↗An organic EL display device capable of preventing generation of pseudo contours is provided. Digital data of pixels in one frame is stored in a frame memory, and display is performed according to the stored digital data. One frame is divided into a plurality of unit frames, each of which is divided into a plurality of sub-frames. In each of the sub-frames, display is performed for a bit corresponding to the digital data.
1. An organic EL display for displaying a frame having reduced pseudo contour, comprising:
(a) a plurality of pixels, each including a driving transistor, an organic EL element driven by the driving transistor, and a storage capacitance connected to the driving transistor;
(b) a plurality of gate lines, each connected to one or more corresponding pixel(s), a plurality of data lines, each connected to one or more corresponding pixel(s), a gate driver for selectively driving the plurality of gate lines, and a data driver for selectively driving the plurality of data lines, wherein each pixel is connected to a single data line and to a single gate line, the gate driver selects one gate line at a time, and pixel data from the data driver on a single data line is written to the storage capacitance in the pixel connected to the single data line and to the selected gate line;
wherein pixel data includes an off-potential or an on-potential, so that on-potential pixel data written to a pixel causes the corresponding organic EL element to emit light, and off-potential pixel data written to a pixel causes the light emission from the corresponding organic EL element to be extinguished;
and wherein the storage capacitance causes the one or more organic EL element(s) in pixels attached to non-selected gate lines to maintain their respective light emission state(s);
(c) a frame memory for storing pixel data corresponding to one frame and providing the stored pixel data to the data driver; and
(d) means for operating the gate driver and the data driver to display the stored pixel data corresponding to one frame in a plurality of successive unit frames, each including a corresponding plurality of successive sub-frames, wherein each unit frame repeatedly displays the same image, has the same frame period and has a number of sub-frames greater than or equal to a respective bit gradation number, and wherein each sub-frame corresponds to a bit of pixel data;
whereby the one frame can be displayed with reduced false contour.
2. The organic EL display of claim 1 , further including:
(e) means for receiving a first and a second frame and detecting a motion vector from the first and second frames; and
(f) means for producing complementary frame images based on the first and second frames and the motion vector;
wherein a single complementary frame image is displayed in a corresponding unit frame of the first frame.
3. The organic EL display of claim 1 , wherein each pixel further includes two or more sub-pixels, each having a driving transistor, an organic EL element driven by the driving transistor, and a storage capacitance connected to the driving transistor.
4. The organic EL display of claim 3 , wherein the organic EL element in each sub-pixel has a respective luminous area, and the luminous areas of all the organic EL elements in a pixel are different.
5. The organic EL display of claim 3 , further including a plurality of power source lines, each supplying a corresponding potential, wherein the driving transistor in each sub-pixel is connected to a single power source line, and the potentials of all the power source lines connected to driving transistors in a pixel are different.
6. The organic EL display of claim 1 , wherein the one frame is displayed during a frame period having a frequency of 60 Hz, and wherein successive unit frames are displayed at a frequency of greater than or equal to 240 Hz.