Fpga-based Injecting Electric Luminescence Display Panel Brightness Compensation

Both LED and OLED belong to injection electroluminescent display technology; they have the similar light-emitting principle and the similar drive circuit. LED is suitable for us to validate some new ideas, which can be adapted easily for OLED by modifying some parameters. A piece of PCB circuit board is designed to verify some ideas about enhancing luminance uniformity of injection electroluminescent display devices. There is a piece of LED display panel, a power supply system and a FPGA driving system in our circuit board.The difference of luminance alteration in adjacent domain for OLED display panels is not so big, and the luminance variedness can be regarded as linear continuousness when the space△d between two adjacent pixels is very small. Geometric plane surface is two-dimension space, so we need to use bilinear interpolation to calculate luminance value of display panels. The method can reduce workload greatly in the aspect of luminance inspection. We obtain time simulation successfully by using QuartusⅡsoftware. Because LED display panels don't meet the above precondition, the method couldn't be used for LED display panels.Currently, progressive scan technology has been used generally for display devices, the light-emitting state of all pixels are controlled by row and column drive circuit. In order to explain the idea fully, several characteristics standards have been adopted in order to expound our experiment results. In the aspect of column drive circuit, a sample compensation method based on column control is presented in the dissertation to enhance luminance uniformity of display panels. Taking the 64×32 LED display panel as an example, where all pixels of each column have an identical BJT(bipolar junction transistor), whose electrical parameters have a certain extent discreteness. Because of the discreteness, different BJTs can have different effect on any whole column pixels. We achieve compensation effect by reducing luminance non-uniformity caused by the BJTs electrical parameters discreteness. By applying the proposed method to the display panel, the luminance uniformity is improved from 88.54% to 95.97% and the improvement amplitude is 8.39%, while the decrease amplitude of luminance non-uniformity is 64.83%.In the aspect of row scan circuit, a successive scans method of adjusting scan-time is presented in the thesis. The method is very feasible for reducing luminance non-uniformity and improving average luminance value to a certain extent. For simplicity, we also adopt the 64×32 LED display panel as an example to expound the new scan method, and we also obtain good result. The decrease amplitude of luminance non-uniformity is 31.34% and the improvement amplitude of the average luminance value is 7.8258%.In this dissertation, chapter 1 is introduction; relative works on the PCB board are introduced in chapter 2 and chapter 3; from chapter 4 to chapter 6, we expound three new ideas, and give the practical operating procedure and result analysis; in the last chapter, the summary and prospect of the whole thesis are presented.