PURPOSE: To improve the tolerance of phosphor dots around the periphery of a panel by carrying out exposure while rotating a light source installed in water so as to form elliptical phosphor dots.
CONSTITUTION: A light source 2 such as a superhigh-pressure mercury-arc lamp which is held in water is installed inside a lamp house 3, and the lamp house 3 is located at a shaft receiving part 4 of a box 1 so that the lamp house 3 can be rotated with a driving motor 5. On the other hand, a panel 6 provided with a shodow mask 10 is positioned at a plate 7 located at the top of the box 1, and a correction lens 6 and a filter 9 are installed between the panel 6 and the light source 2. After that, elliptical phosphor dots, which have a shorter diameter extending in the radial direction of the panel 6 and a longer diameter extending the tangential direction of the panel 6, are formed by rotating the light source 2 by 180°. As a result, the tolerance of the above phosphor dots to an electron beam spot in the peripheral part of the panel 6 can be improved, and the color purity and the manufacturing yield of a Braun tube can be increased.
FUJIMURA TAKASHI
KUKI KOUJI
