JPS6433520A - Liquid crystal optical modulator - Google Patents

Abstract

PURPOSE:To make direct use of zero order light of diffraction so that the generation and annihilation of the diffraction of high visibility are obtd. with a low voltage by impressing the voltage to a cell constituted of fine stripe- shaped electrodes and controlling the generation and annihilation of the diffraction by on and off of the voltage. CONSTITUTION:At least one electrode of a liquid crystal cell 16 constituted by holding a liquid crystal in place between two sheets of electrode substrates 11 and 12 is constituted of periodic electrode patterns. The cell has the cell gap equal to or smaller than the pitch of said periodic electrode patterns. A region having the different directors of the liquid crystal molecules is formed when the voltage is impressed between the electrode part 23 and non-electrode part 24 of the periodic electrode pattern. This modulator utilizes the change in the visibility of the zero order diffracted light when the voltage is impressed and when the voltage is not impressed in the diffraction phenomenon which takes place at the passage of the incident light approximately perpendicularly on the liquid crystal cell 16 through the above-mentioned region. The liquid crystal optical modulator having high productivity and reliability is thereby obtd.