Liquid crystal display having light indicia on a dark background

Claim 1

A liquid crystal display in which an image appears light on a dark background, comprising a layer of nematic liquid crystal material of positive dielectric anisotropy sandwiched between transparent parallel plates, films of transparent conductive material on selected areas of the plates and in contact with the liquid crystal material, the plates being treated to effect a twisted-nematic structure such that polarized light will be rotated through 90° in passing through the polarizer, first polarizer means on the front of said display, second polarizer means behind said display covering the entire area of the display except those selected areas defined by the transparent conductive material on one of the transparent plates, and third polarizer means adjacent said second polarizer means and crossed with respect thereto such that polarized light which passes through the transparent parallel plates in areas outside the selected areas will not pass through the second and third polarizer means.