Automatic primary color convergence alignment system for projection

Abstract

An automatic primary color component covergence alignment system for a color television display apparatus is presented whereby an alignment pattern is periodically displayed in peripheral regions of the television screen, in each of the primary colors during respective successive correction intervals, the pattern positioned such as to fall upon photo-sensitive devices disposed at the screen periphery. Adjustment of pattern position is executed during each correction interval, based on position data derived from output signals from the photo-sensitive devices, such as to align the alignment pattern with predetermined reference positions. During each period between these sets of correction intervals, the position data thus derived are held stored and are continuously utilized for controlling the deflection of respective electron beams used in generating the primary colors, to thereby implement automatic convergence alignment adjustment.