Yoshito Date

60.5L: Late‐News Paper: An Improved Current Driving Method for 256‐Level Full Color Active Matrix OLED Displays

Because full-color OLED displays are RGB and the current-luminance characteristics of OLED devices differ from one another, their white balance adjustment is difficult. Another problem is that OLED displays draw a large current when images are displayed at high luminance, which causes heating and deterioration. We propose an improved current driving method to solve both problems, and we developed a current-output source driver IC which achieves 256 levels each for RGB, and a full-color active-matrix OLED display with a 3.46-inch diagonal and current-driven 320 RGB × 240 pixels (QVGA).

36.5L: Late‐News Paper: Development of Source Driver LSI for AMOLED Displays Using Current Driving Method

We have developed a source driver LSI for active matrix OLED displays using the current driving method. The current driving method is better able to overcome non-uniformity of pixel transistor characteristics, such as threshold voltage and mobility, than either voltage or PWM driving. We propose two current driving topologies: a new type of reference source distribution and a new type of gamma correction circuits.

60.3: Development of a Uniform Current Topology for AMOLED Source Driver LSI

Because OLED luminance depends on the current, the current method is the most suitable for active matrix OLED (AMOLED) displays. However, OLED devices also need a very low, uniform current. A source driver LSI based on silicon bulk provides several advantages over LTPS-TFTs and a-TFTs. We have developed uniform current topology for our AMOLED source driver LSI. In this paper, we introduce the design methodology for this uniformity.