Patent ID: 6495976
Filing Date: 2002-12-17
Classification: H01J

Abstract:
A color-purity measuring method comprising the steps of:providing an adjusting coil at a neck portion of a color cathode ray tube and providing color image pickup means for photographing the screen of the color cathode ray tube; inputting a monochrome signal of any one of red, green, and blue colors into the color cathode ray tube; thereafter decomposing an image pickup signal obtained from the color image pickup means into red, green, and blue color signal components while causing an electric current made to flow through the adjusting coil to vary to thereby measure the intensity of each of them; thereby determining an amount of movement of an electron beam with respect to a unit value of electric current for the adjusting coil according to the value of the electric current supplied to the adjusting coil and the location distance between luminous regions of the red, green, and blue colors on the color cathode ray tube; and thereby obtaining an amount of color-purity at a relevant measured point according to the amount of movement of an electron beam with respect to a unit value of electric current for the adjusting coil and the value of an electric current corresponding to the intensity peak of the monochrome signal.