Convergence correction apparatus for delta-gun color cathode ray tube displays

摘要

Convergence correction for a delta-gun CRT at all locations on the CRT screen is accomplished by separately implementing the general equation for convergence in that coordinate system peculiar to each of the gun's location relative to the screen and modifying the equation coefficients in each of its four quadrants to effect convergence in that quadrant. The quadrants of each of the gun's coordinate system is the same as the quadrants of the CRT screen thereby allowing each of the coefficients to be changed or adjusted only when the terms it multiplies is zero. Complete convergence correction for the entire screen may be accomplished using only nine screen locations. A unique triangular convergence symbol corresponding to the gun locations is placed at each of these nine locations to adjust the equation coefficients, each leg of the convergence symbol being of a color which optimizes the viewability of the convergence of a particular gun.