Patent ID: 6031557
Filing Date: 2000-02-29
Classification: G03B,G09G

Abstract:
A method for bi-directionally sweeping an electron beam of a color CRT, to illuminate a plurality of color phosphor areas on a face of said color CRT, and to expose a photosensitive medium with light emitted from said face of said color CRT, said method comprising:(a) aligning a first line of said photosensitive medium with a first vertical position in a first color phosphor area on said face of said color CRT;(b) positioning said electron beam at said first vertical position in said first color phosphor area on said face of said color CRT;(c) sweeping said electron beam horizontally inside said first color phosphor area in a forward direction at said first vertical position;(d) modulating said electron beam, during said sweeping of step (c), with a first row of dot row data for said first color phosphor area derived from an image, wherein said first row of dot row data is processed in a forward order;(e) exposing said first line of said photosensitive medium during said sweeping and modulating of steps (c) and (d);(f) aligning said first line of said photosensitive medium with a first vertical position in a second color phosphor area on said face of said color CRT;(g) positioning said electron beam at said first vertical position in said second color phosphor area on said face of said color CRT;(h) sweeping said electron beam horizontally inside said second color phosphor area in a reverse direction at said first vertical position in said second color phosphor area, wherein said reverse direction is opposite said forward direction;(i) modulating said electron beam, during said sweeping of step (h), with a second row of dot row data for said second color phosphor area derived from said image, wherein said second row of dot row data is processed in a reverse order opposite said forward order; and(j) exposing said first line of said photosensitive medium during said sweeping and modulating of steps (h) and (i).