Patent ID: 6894672

Claim:
A liquid crystal display device, comprising: a first substrate provided with one or more first electrodes, a second substrate provided with one or more second electrodes, and a twisted nematic liquid crystal material between the two substrates, in which, viewed perpendicularly to the substrates, overlapping parts of the electrodes define pixels, wherein the display device is provided with means for adjusting an operating voltage of the liquid crystal display device by: supplying an input voltage to a measuring element positioned between the first and second substrates; measuring a current through the measuring element, the current based on the input voltage; determining a derived current using the measured current; and adjusting the operating voltage using the derived current; and wherein the means for adjusting are capable of adjusting the operating voltage using the derived current by: identifying a maximum value in the derived current; and identifying a voltage in a sawtooth voltage signal that is coincident with the maximum value in the derived current, the identified voltage in the sawtooth voltage signal comprising the operating voltage of the liquid crystal display device.