Method and apparatus for measuring convergence with respect to a color CRT using a color CCD camera

摘要

An apparatus and method are provided for measuring convergence of the Red-Green-Blue (R.G.B.) signals of a color cathode ray tube (CRT) using a color charge coupled device (CCD) camera. A uniform R.G.B. brightness value is picked up by the color CCD camera at all positions of the CRT screen when the color CCD camera images the screen, thus enabling convergence to be more accurately measured and adjusted. Test patterns having a constant R.G.B. brightness value are displayed on the screen of the CRT by a pattern generator. The displayed test patterns are picked up by the color CCD camera, and when the R.G.B. brightness values differ from a corresponding reference brightness value, a controller adjusts the intensity of each of the R.G.B. signals of each test pattern by suitably controlling the pattern generator. A uniform R.G.B. brightness value is thus provided for all test patterns displayed on the CRT screen. Only after the R.G.B. brightness value has been made uniform is convergence measured, thereby increasing the reliability of the convergence measurement data.