Convergence correction apparatus, for TV set or projection display, has a small number of sensors arranged outside the visible screen area to provide signals used when convergence raster is displayed on the screen

摘要

The region of a screen (1) which can be seen is surrounded by an edge (18) outside which 8 optical sensors (I - VIII) are arranged, while a convergence raster (19) is overlaid on the screen. The raster is formed by 13 horizontal and 15 vertical lines (21, 22) and extends beyond the edge, while the sensors are connected to an evaluation circuit, emitting an appropriate signal when light falls onto one of the sensors. Convergence correction values for the screen can then be calculated. AN Independent claim is included for a method for convergence correction in a projection TV set.