Patent ID: 6483313
Filing Date: 2002-11-19
Classification: H04N

Abstract:
An apparatus for measuring convergence of R.G.B. beams of a color CRT, said apparatus comprising:a pattern generator for generating a test pattern of R.G.B. signals on a screen of a color CRT; a color CCD camera for imaging the test pattern formed on the screen of the color CRT to produce an imaged test pattern having R.G.B. brightness values; a comparator for comparing the R.G.B brightness values of the imaged test pattern of the color CCD camera with a predetermined reference brightness value; and a controller for adjusting, in intensity, each of the R.G.B signals of the test pattern generated by the pattern generator so as to produce a uniform R.G.B brightness value when the R.G.B brightness values of the imaged test pattern are determined by said comparator to be different from said reference brightness value, and for thereafter measuring convergence, said controller controlling the pattern generator so as to adjust the intensity of the R.G.B signals of each test pattern in order to produce a uniform R.G.B brightness value for all test patterns, each test pattern contacting a crossing point of an overall cross-hatch pattern, being positioned within a respective discrete area defined by crossing lines of the cross-hatch pattern, and being of a square shape.