US Patent 7245296 Active matrix display device

A display device with capacitive display pixels, in which a drive scheme is used for capacitive coupling of voltages to enable reduced column voltage swings to be obtained. Each pixel has two storage capacitors. The use of two storage capacitors provides some freedom in the choice of the magnitude of the voltage swing provide on one terminal of one of the storage capacitors. The first capacitor (C1) of all pixels of the display may be grounded, and only the second capacitor (C2) is subjected to changes in voltage to be capacitively coupled to the display cell. This provides a flexible capacitor line drive type scheme.