关键词: LED显示屏, 偏色, 首行偏暗, 灰度

Abstract: For two common problems, color cast and 1^st dim line in fine pixel pitch LED display, a circuit which could solve the two problems at the same time is designed. The color cast occurs because the parasitic parameters of red, green, blue LEDs are quite different. It affects the display which eventually causes the color cast. The first dim line occurs when the column voltage is higher than the other lines, so the current through the first line’s LEDs is smaller than the normal value. At last, the first line would be darker than the other lines. The solution presented tries to compensate the PWM driver signal and offer different compensation levels. After compensation, the display shows accurate gray level and uniformity, which means the two problems are well solved.

Key words: LEDdisplay, colorcast, 1stdimline, graylevel