| 摘要 |
PURPOSE:To enable landing transfer quantity to be decreased extremely even if the sound pressure of a speaker is applied, by carrying out a hardening process on the edge portion of a shadow mask which includes the nonperforated portion of the circumference of a perforated portion and a skirt portion, in order to reduce the resonance of the perforated portion of the shadow mask. CONSTITUTION:A color picture tube 1 comprises a panel 3 which is provided with a fluorescent screen 2 on the inner surface thereof, a vacuum envelope made of a funnel 4 and a neck 5, an electron gun 6 mounted in the neck 5, a shadow mask 7 which is provided opposite to the fluorescent screen 2 and a mask frame 8 which retains this shadow mask 7. The shadow mask 7 comprises a perforated portion 71 in which electron beam transit openings 7a are bored and a edge portion 74 which includes the nonperforated portion 72 of the circumference of this perforated portion and a skirt portion 73, and a glass layer 10 is formed so as to be hardened on an area which extends from a portion where is 0.5-1.0mm away from the boundary of the nonperforated portion 72 and the perforated portion 71 to a position where the welded portion 9 of the skirt portion 73 and the mask frame 8 is eliminated. As to the forming method of the glass layer 10, frit glass is spread and burned by a high temperature furnace.
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