High-Speed Programming Architecture and Image-Sticking Cancellation Technology for High-Resolution Low-Voltage AMOLEDs

We have developed a high-speed programming architecture and an image-sticking cancellation technology that utilize a pixel circuit with only four TFTs for LTPS active-matrix organic light-emitting-diode (OLED) displays. High-speed programming is realized through controlled-amplitude precharging. The gate voltage of the drive TFT in data programming converges the fixed voltage on very low voltage and very short programming time by controlled-amplitude precharging. This means that an image-lag-free picture can be achieved on a low-power high-resolution display. Image-sticking cancellation is realized by detecting the OLED anode voltage difference between neighboring pixels. When there is a large amount of OLED characteristic shading over an entire panel, it is difficult to detect the absolute value of the OLED characteristic to judge image sticking. Therefore, detecting the OLED difference between neighboring pixels is useful. A 3.0-in 202 × 267 ppi full-color panel was developed. This panel could produce image-lag-free pictures at low-voltage (4-V) operation because of high-speed programming, and we confirmed that image sticking could be detected and canceled by the proposed cancellation technology.