Patent ID: 6235165
Filing Date: 2001-05-22
Classification: C23C,H01J

Abstract:
A method of making a light quantity correction filter for exposure of a phosphor screen of a color cathode ray tube, comprising:providing in an evacuated container an evaporation source, a transparent substrate having a surface over which an inorganic material from the evaporation source is to be deposited and an evaporation amount distribution controlling sheet that has a plurality of openings formed so that a rate of opening area increases gradually toward a center of the evaporation amount distribution controlling sheet and is disposed between the evaporation source and the transparent substrate;evaporating material from the evaporation source for deposition on the surface of the transparent substrate; andcontrolling an amount of evaporated inorganic material deposited on the transparent substrate with the distribution controlling sheet,wherein the controlling step comprises oscillating at least one of the evaporation source, the transparent substrate and the distribution controlling sheet in a direction substantially perpendicular to a longitudinal direction of the openings with respect to the others during the evaporation step so that the amount of inorganic material deposited on the transparent substrate, which is nonuniform, becomes uniform in a vicinity of a boundary between the openings and a shielded portion, and a desired transmittance distribution is obtained in the transparent substrate.