Dai Nippon Printing Co., Ltd.

Takuya Ogio

Akira Makita

Hirofumi Hideshima

Takayasu Komatsu

Yutaka Matsumoto

Hiromitsu Ochiai

Toshimu Watanabe

The present invention provides a shadow mask having an improved resistance to an impact such as vibration or dropping so as to keep a constant quality of a color cathode-ray tube. The object is achieved by a shadow mask in which throughholes are formed, each of the throughholesandhaving a rear side hole portionorthrough which an electron beam enters and a front side hole portionorthrough which the electron beam is emitted so as to form a beam spot having a prescribed shape on a surface to be irradiated; wherein, each of the throughholesandhas a ridge portionorformed by intersection of a taper surfaceorof the rear side hole portionorand a taper surfaceorof the front side hole portionor; the taper size T represented by a value a half the difference between the hole width S at endorof the front side hole portionorand the hole width Q at the ridge portionoris within a range of from 30 to 40% of the thickness t of the shadow mask; and the ridge portion is formed at a sectional height of up to 35 &#x3bc;m from the endof the rear side hole portionor

Shadow mask for a cathode ray tube

A shadow mask is formed from a plate member comprising an outer frame portion, a body portion of a shadow mask having an outer peripheral line formed through an etching process and a plurality of connection portions through which the body portion of the shadow mask is supported by the outer frame portion. The shadow mask is formed from the plate member by removing the outer frame portion from the body portion of the shadow mask. In this process, a break portion is formed to the shadow mask by removing the outer frame portion so as to be recessed inward from the outer peripheral line of the shadow mask.

Shadow mask, plate member therefor and method of manufacturing shadow mask

Growing community of inventors

Tokyo-to, Japan

Takuya Ogio