Patent ID: 7218302

Claim:
A method for driving an optical modulator using liquid crystal, said liquid crystal optical modulator comprising: a first substrate having thereon a composite electrode in which a plurality of parallel stripe conductive electrodes are arranged and said plurality of parallel stripe conductive electrodes are electrically connected by one or more connection stripe electrodes; a second substrate having thereon divided opposed electrodes each corresponding to a predetermined area on said composite electrode; and an optical element including a liquid crystal molecule layer held between said first substrate and said second substrate, said liquid crystal optical modulator configured in such a way that said connection stripe electrode has signal electrodes at a predetermined interval to which a control signal is applied; that, by applying a predetermined voltage to the signal electrodes, a linear potential gradient is generated in the connection stripe electrode between the signal electrodes; that a predetermined opposed voltage is applied to said divided opposed electrodes; and that the applied voltages cause a modulation in a refractive index of the liquid crystal molecule layer via a curve modulation area of electro-optical characteristics of homogeneously aligned or homeotropically aligned liquid crystal, wherein there are a period in which two drive waveforms, with equal amplitude and equal frequency but 180 degrees out of phase to one another, are applied to the predetermined signal electrodes that receive drive waveforms and a period in which an ac (alternate current) bias is applied to the liquid crystal molecule layer.