Raymond G. Greene

AMLCD flicker model considering the V/sub T/ shift in a-Si:H TFT

The observed development of flicker with time in active matrix liquid crystal display (AMLCD) panels has been correlated to the threshold voltage shift of the thin film transistors (TFTs) used in panels. The effect of a threshold voltage shift on the panel flicker was calculated using a flicker model developed here. One set of AMLCD panels used for the flicker characterization employed top-gate TFTs, while a second set employed bottom-gate TFTs. Optical measurements to determine the flicker voltage as a function of aging were performed on both types of panels. Electrical characterization of the TFTs extracted the threshold voltage from the C-V measurement. Samples of the TFTs were available on the kerf strips for both panel types, and ensured that the optically characterized panels and the TFTs electrically characterized were manufactured in the same batch for each of the two panel types.

P-34: Impact of Birefringence on Large LCDs

Minimizing the spatial variation of polarization is critical to tiled AMLCD image quality. With the advent of large tiled AMLCD, low spatial frequency artifacts may become visible. Component birefringence variation of a few nanometers can produce viewer detectable luminance variations. Jones matrix formulation is used to model this effect and compare to experimental measurements.