System for the display of images in half tones on a matrix screen

Abstract From the Canadian patent

The system enables the making of half-tones by using the control circuits of the matrix which are not usually designed for this purpose; it produces no flicker effect. It has a memory image with N (greater than or equal to 2) memory planes to store therein light information relating to each pixel in an N-bit word. The planes are read sequentially and thus make N-l half-tones. In the simplest case (N=2), two planes are used and a first image is produced where any pixel is formed by a first bit extracted from a first plane, and is preceded and followed in rows as well as in columns, by a pixel formed by a first bit extracted from the other plane. The addressing is then determined to produce a …