Liquid crystal matrix with contrast enhancement

Abstract

Abstract The present invention is directed to an arrangement or system for modulating coherent light beams by utilizing a liquid crystal matrix having a plurality of coacting electrode pairs to apply an electrical field to change the light transmitting state of the portion of the liquid crystal associated with each electrode pair from a non-scattering state to a scattering state. To separate the scattered light from non-scattered light and obtain the intensity modulation, a filtering means for removing the scattered radiation is provided for each of the electrode pairs of the matrix and comprises a focusing element having a mask or partition with a window or aperture which partition is disposed at the focal plane of the element with the window or aperture at the focal point to enable the passing of the focused nonscattered light rays with the filtering of the scattered rays. Preferably, the electrode pairs are provided by forming parallel strips of electrically conductive material on the plates of the matrix with the strips of one plate being arranged at 90* to the strips the other matrix so that a coacting electrode pair is provided at each point at which two strips cross or overlap. The focusing elements can be lenses such as cylindrical lenses, fresnel zone plates or concave mirrors. The windows in the partition can be either substantially circular aperatures such as perforations through either a sheet or foil or slit-like apertures. The focusing elements or lenses are preferably formed in one of the plates of the liquid crystal matrix such as by pressing or embossing. A preferred method of forming the partition for the arrangement is to project light through the focusing elements, such as those embossed into a carrier plate of the matrix, onto a sheet of material having a photosensitive layer which sheet is positioned at the focal plane of the focusing elements to develop the light transmitting windows. If a foil is used as the partition, the intensity of the light radiation being projected through the focusing elements can be of a sufficient magnitude to burn the aperatures into the foil to form the light transmitting windows.

Inventors

• 👤 H Kiemle
• 👤 U Wolff

Bibliographic Details