Patent ID: RE41233

Claim:
A cathode ray tube comprising: a panel having a substantially flat outer surface and an inner curved surface with a phosphor screen, the panel having a substantially rectangular effective screen portion with two long sides parallel to each other, two short sides parallel to each other and four rounded edges each interconnecting each a long side and the a neighboring short side respectively , the effective screen portion being structured such that a first line V 1 interconnecting centers of the long sides, a second line H 1 interconnecting centers of the short sides and a third line D 1 interconnecting centers of the rounded edges opposite to each other meet at a point, the effective screen portion having a first thickness Tv at the centers of the long sides, a second thickness Th at the centers of the short sides, a third thickness Td at the centers of the edges and a fourth thickness Tc at the meeting point of the first to third lines V 1 , H 1 and D 1 ; wherein the ratio of the second thickness Th to the third thickness Td while subtracting the fourth thickness Tc from each thickness satisfies the following condition: 0.75≦(Th−Tc)/(Td−Tc)≦0.85, and the ratio of the first thickness Tv to the third thickness Td while subtracting the fourth thickness Tc from each thickness satisfies the following condition: 0.75≦(Tv−Tc)/(Td−Tc)≦0.85.