An organic complementary differential amplifier for flexible AMOLED applications

Active Matrix Organic Light-Emitting Diode (AMOLED) displays offer distinct benefits for portable electronics applications, including light weight, high brightness, low power consumption, wide viewing angle, and low processing costs. They also are attractive candidates for highly flexible substrates. In active matrix displays, a small transistor circuit is used to drive each OLED device. Recently developed organic thin film transistors (TFTs) have made complementary TFT circuits possible on flexible substrates. We present an organic complementary amplifier as an AMOLED pixel driver. The 7 TFT amplifier circuit is able to achieve less than 1% current drift for a 2x Vtchange, and fill factor of 75% with a 20μm minimum channel length. The amplifier combines programming speed comparable to an equivalent 2-TFT voltage-programmed circuit with stability akin to a 4-TFT circuit, the trade-off being higher TFT count.