Patent Number: 6,294,863

Title: Color cathode ray tube having a shadow mask with a plurality of strip shaped reinforcing beads

Abstract: A color cathode ray tube is provided with a shadow mask having a mask body including a substantially rectangular effective surface in which a large number of electron beam passage apertures are formed. A plurality of reinforcing beads are formed on the effective surface, and project therefrom to have heights which varies in accordance with positions such that in at least a part of an area for provision of the reinforcing beads, the heights of the reinforcing beads satisfy the following relationship: where dx1 is the height measured at a first position which is apart from a longer axis of the effective surface and a distance x1 apart from a shorter axis thereof, dx2 is the height measured at a second position which is further apart from the longer axis than the first position and a distance x2 apart from the shorter axis, dy1 is the height measured at a third position which is located on the shorter axis and a distance y1 apart from the longer axis, dy2 is the height measured at a fourth position which is a distance apart from the shorter axis and a distance y2 apart from the longer axis, and the distances x1, x2, y1 and y2 satisfy the following relationship: x1=x2=y1=y2.

Inventors: Shimizu; Norio (Fukaya, JP), Nakagawa; Shinichiro (Fukaya, JP), Inoue; Masatsugu (Kumagaya, JP)

Assignee: Kabushiki Kaisha Toshiba

International Classification: H01J 29/07 (20060101); H01J 029/80 ()

Expiration Date: 09/25/2018