An integrated circuit for feedback control & compensation of an organic LED display

Abstract

Organic LEDs (OLEDs) have the potential to be used to build large-format, thin, flexible displays. Currently, the primary drawback to their usage lies in the difficulty of producing OLEDs which emit light at a constant and predictable brightness over their lifetime. A solution has been proposed which uses organic photo-detectors and optical feedback to control the desired luminosity on a per-pixel basis. This thesis demonstrates the design and fabrication of an integrated silicon control chip and an organic pixel/imaging array, which together form a stable, usable display. The simulation, verification, and testing of this OLED display demonstrates the utility of our solution. In particular, this thesis focuses on the Loop Compensator silicon design and feedback aspects of this circuit. The results demonstrate that the Loop Compensator has the desired DC and frequency characteristics with a measured gain of 100.2 and a variable dominant pole located at digitally-selectable frequencies (using a programmable capacitor array) of 10.8 Hz, 13.5 Hz, 22.8 Hz, and 64.8 Hz, given a clock frequency of 20 kHz.