An improved AM OLED pixel circuit and method of wide dynamic range dimming for AM OLED displays are disclosed that maintain color balance throughout the dimming range, and also maintain the uniformity of the luminance and chromaticity of the display at low gray-levels as the display is dimmed to lower luminance values. As such, AM OLED displays can meet the stringent color/dimming specifications required for existing and future avionics, cockpit, and hand-held military device display applications. Essentially, the OLED pixel circuit and method of dimming that are disclosed use Pulse Width Modulation (PWM) of the OLED pixel current to achieve the desired display luminance. Two example circuits are disclosed that externally PW modulate the common cathode voltage or common power supply voltage to modulate the OLED current in order to achieve the desired display luminance. Three example circuits are disclosed that incorporate additional transistor switches in the pixel circuit to modulate the OLED current during the frame time. By PWM of the OLED current, in combination with data voltage (or current) modulation, wide dynamic range dimming can be achieved while maintaining the color balance and the luminance and chromaticity uniformity required over the surface of the display involved.

公开了一种改善的AM OLED像素电路和对AM OLED显示器进行宽动态范围调光的方法，其能在整个调光范围内保持颜色平衡，且当显示器调光到较低亮度值时还可在低灰度级处保持显示器的亮度和色度的均匀性。基本地，这里公开的OLED像素电路和调光方法使用OLED像素电流的脉冲宽度调制来获得理想的显示亮度。为了获得理想的显示亮度，公开了对公共阴极电压或公共电源电压进行外部PW调制来调制OLED电流的两个实例电路。公开了在像素电路中结合另外的晶体管开关来在帧时间过程中调制OLED电流的三个实例电路。通过与数据电压（或电流）调制结合，对OLED电流进行PWM，可实现宽动态范围调光，同时保持所涉及的显示器表面上所需的颜色平衡以及亮度和色度均匀性。