US 6,548,954 B1Granted

Color cathode ray tube with black matrix holes having different diameters

AssigneeHitachi, Ltd.

InventorsKazuki Ishii, Hirofumi Muto

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Abstract

A color cathode ray tube has a panel portion in which a black matrix layer and plural phosphor layers are formed on the inner surface of its faceplate. The black matrix layer is provided with first-color holes for a first phosphor layer and second-color holes for a second phosphor layer. The first-color holes and the second-color holes become gradually larger in diameter from the central portion toward the corner portions of the faceplate, and the rate of variation in the diameters of the first-color holes and the rate of variation in the diameters of the second-color holes are different from each other. According to the above-described construction, there is provided a cathode ray tube in which white uniformity is improved over the entire screen.

Claims21

Dependent claims

A cathode ray tube comprising a panel having a nearly flat outer surface and an inner surface which has an outward-convex curved surface, holes of a black matrix each of which corresponds to the color of one of phosphors for three colors being formed in the inner surface of the panel,

wherein letting H1c, H2c, H1d and H2d be, respectively, a black matrix hole diameter corresponding to a phosphor for a first color in the center of a screen, a black matrix hole diameter corresponding to a phosphor for a second color in the center of the screen, a black matrix hole diameter corresponding to a phosphor for the first color in a diagonal periphery of the screen, and a black matrix hole diameter corresponding to a phosphor for the second color in the diagonal periphery of the screen,
|H1d−H1c|≠|H2d−H2c|,
where a difference in hole diameter for the first color between the center and the periphery and a difference in hole diameter for the second color between the center and the periphery are different from each other in a direction in which a difference in spectral transmittance between the center and the periphery of the panel is compensated for.

Dependencies are inferred from the claim text.