| Organic light emitting display(OLED) have attracted much attention and rapid devel-opment in recent years because of its excellent characteristics,such as self-light emitting, fast response and can be used for flexible displays. Active matrix(AM) OLED is the key to high-resolution and high-quality display, and microcrystalline silicon(μc-Si) TFT is very suitable for AMOLED as its good mobility and better stability. In this paper, a display driv-ing module based on FPGA was designed by the research of the 7-inch AMOLED usingμc-Si TFT technology.According to characteristics ofμc-Si TFT, the analog gray scale implementation is se-lected. The brightness of the OLED is non-linear relationship with the data voltage, so gamma correction is need for bias of gray scales. Through the intergrated gamma correc-tion in chip and digital gamma correction, the accuracy of gray scales is effectively im-proved.As the OLED driver ICs is the lack, LCD driver ICs can only be used. By studying the characteristics of LCD driver ICs and combined with the actual demand of driving OLED, a method connecting screen with ICs is present. Through using double data-driver and con-troling the polarity of the ICs, the problem that dot inversion of LCD Driver ICs is not matching AMOLED is resolved, and the brightness is doubled.Otherwise, FPGA-based hardware driving circuit board and the display driver control program described with the Verilog hardware description language are designed. By scaling module the resolution of video and screen is matching, and using the FPGA's internal FIFO as the output cache can greatly reduce difficulty of PCB layout and hardware costs.The simulation results in QUARTUS II and the tested by oscillograph on the timing and controlling signals are provided, and consistent with the design. The results indicate that the driving circuit functions correctly, and this design can implement the dynamic dis-play on 7-inch microcrystalline silicon TFT AMOLED with 64 gray scales. |
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