A silicon current sensing amplifier and organic imager for an optical feedback OLED display

Abstract

Organic LEDs (OLEDs) have the potential to be used to build thin, flexible cost effective displays. Currently, the primary drawback to their usage lies in the difficulty of producing OLEDs that emit light at a constant and predictable brightness over their lifetime. This leads to a non-uniform brightness and a limited effective lifetime in an OLED display. The solution presented herein uses organic photodetectors on a per-pixel basis using a column-parallel architecture for optical feedback to control the desired luminosity. The integrated silicon control chip and organic imager array, together with the OLED array, form a stable display. In particular, this thesis focuses on the design and fabrication of the Current Sensing Amplifier circuits for the organic imager array in an optical feedback OLED display. The results demonstrate functionality of the high gain Current Sensing Amplifier with a measured transimpedance gain of 496 MQ using a clock frequency of 20kHz, 50% duty cycle, and a Programmable Gain setting of 5x.