Light exposure apparatus for manufacturing color picture tubes

Claim 1

In a light exposure apparatus of the class having a light source, an illumination intensity correcting filter, an exposing light path correction lens, a face plate provided with a colour selection electrode of a colour picture tube, and a casing wherein said light source, said illumination intensity correcting filter and said exposing light path correction lens are disposed in said casing by taking a predetermined position, and said face plate is removably disposed on the top portion of said casing so as to be exposed to light from said light source said illumination intensity correcting filter and said exposing light path correction lens, the improvement wherein said illumination intensity correcting filter is formed as an assembly of individual elements, said elements being sufficient in number to obtain the number of desired elemental changes in light transmissivity required for exposing the area of said screen, each of said elements operable to provide a region restricting light transmission therethrough corresponding to the exposure light quantity which is required to expose the corresponding part of a fluorescent screen coated on the inner surface of said face plate, each said element being formed discretely, each of said regions having a predetermined particular value of light transmissivity distributed in accordance with the desired elemental area distribution of said exposure light quantity.