Patent ID: 6803710
Filing Date: 2004-10-12
Classification: H01J

Abstract:
A shadow mask for a Braun tube having a plurality of slots forming beam spots, each having substantially a rectangular shape, uniformly on a fluorescent surface of a color Braun tube, characterized in thatsaid slots include a slot having substantially a rectangular shape and formed at a portion near an axis of ordinate passing a central portion of the shadow mask and a curved slot formed on an outer peripheral side thereof apart from the axis of ordinate, said rectangular slot is composed of a back side opening formed on an electron beam incident side through an etching process so as to have substantially a rectangular shape, a front side opening formed through the etching process so as to have substantially a rectangular shape having a large area so as to allow the electron beam to pass and side wall sections inclining between the back side opening and the front side opening, said curved slot is composed of a back side opening formed on the electron beam incident side through the etching process so as to be curved such that both longitudinal end portion thereof are apart from said axis of ordinate, a front side opening formed through the etching process so as to have substantially a rectangular shape having a large area so as to allow the electron beam to pass and side wall sections inclining between the back side opening and the front side opening, and said curving of the back side opening of the curved slot becomes large as both the longitudinal end portions are apart from the axis of ordinate.