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Proceedings Paper

Invar mask for color cathode ray tubes
Author(s): K. C. Chen; W. Y. Ho; C. H. Tseng
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Paper Abstract

Color CRTs for both consir and display applications are shifting toward larger, flatter and higher resolution. Manufacturing of these tubes with good viewing quality,such as color purity, is a major engineering challenge. One critical area where developnt work is desperate in shadow mask, and thus is the goal of this paper. A flatter RT needs a flatter shadow mask. However, this requirement triggers many engineering concerns, for example: thermal expansivity, formability, and emissivity of the shadow mask. Invar, an Fe-36wt%Ni systematically studied in terms of all requirements described above. It is desired that the mask possesses higher Young's modulus and lower yield strength for the better formability. Invar unfortunably possesses lower Young's modulus and higher yield strength than that of conventional shadow mask material (i.e., AK steel ). Process development to increase the Young's modulus and decrease the yield strength employing proprietary heat treatments and forming process have been studied. It is learned that a material with the grain size of ASTM 6, heat treated at 1000°C, and formed at 2lObC will give an excellent formability. Etnissivity of the Invar mask after forming was also studied under variour conditions. An exnissivity of about 0.9, which is equivalent to that of conventionally blackened AK mask, was obtained through blackening of the Invar mask in steam atmosphere at 600°C for 40 minutes.

Paper Details

Date Published: 27 October 1992
PDF: 7 pages
Proc. SPIE 1815, Display Technologies, (27 October 1992); doi: 10.1117/12.131297
Show Author Affiliations
K. C. Chen, Chunghwa Picture Tubes, Ltd. (Taiwan)
W. Y. Ho, Chunghwa Picture Tubes, Ltd. (Taiwan)
C. H. Tseng, Chunghwa Picture Tubes, Ltd. (Taiwan)

Published in SPIE Proceedings Vol. 1815:
Display Technologies
Shu-Hsia Chen; Shin-Tson Wu, Editor(s)

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