Liquid crystal device using a Fresnel collimating lens for improving uniformity of display contrast ratio

摘要

There is disclosed a liquid crystal display device having very uniform contrast ratio for use with such a projector as an overhead projector. The liquid crystal display device comprises a liquid crystal display cell having a thin film of liquid crystal material sandwiched between transparent electrodes formed on opposing transparent substrates and a Fresnel collimating lens disposed before the cell in the direction of light traveling through the cell and for collimating the light in parallel light beams from a condenser lens in the projector.