Scaling theory of liquid-crystal displays addressed by thin-film transistors

The proposed scaling theory for designing thin-film transistor/liquid-crystal displays (TFT/LCD's) addresses the need for a new design theory for fabricating TFT panels. A constant field is assumed, the same as for MOSFET scaling. A constant voltage is assumed based on the fact that the operational voltages of liquid-crystal cells are not easily scaled. Scaling is found to improve the gate delay and offset voltage characteristics in spite of the narrower busline width and the smaller pixel capacitance. The same improvements are observed even in larger, higher-resolution panels. This scheme to scale the pixel capacitance can be extended to an unloaded-pixel scheme in which there is no storage capacitance in the pixels. The trade-off in this scheme is between a short charging-time constant and a large aperture ratio, and a large voltage offset and a short discharging-time constant. The scaling theory is shown to be a valuable tool to design the next-generation TFT panels.