Patent ID: 6972807
Filing Date: 2005-12-06
Classification: H04N

Abstract:
1. A projection television which magnifies images displayed on cathode ray tubes (CRTs) for the colors red, green, and blue using lenses and projects the magnified images onto a screen, the projection television comprising a convergence control apparatus capable of adjusting the convergence while an input image signal is displayed, the convergence control apparatus comprising: an image signal decoder which processes the input image signal to generate a data signal, horizontal and vertical synchronous signals, and a start signal indicating the start of either the horizontal or vertical synchronous signal; a convergence control unit which simultaneously projects a normal image signal output from the image signal decoder onto the screen and performs convergence control using a predetermined region around the screen displaced from a visible region of the screen according to a convergence control command; and a main microcomputer which inputs the convergence control command to the convergence control unit when the start signal is input from the image signal decoder, stops the convergence control when a completion signal is input from the convergence control unit, and performs a control operation to continuously display the image signal during the convergence control.