Asahi Glass Company, Limited

Hiroshi Yamasaki

Naoya Shimizu

Tsunehiko Sugawara

Toshikazu Ikezawa

A glass panel for a cathode ray tube including a substantially rectangular face portion and a skirt portion. Further constituting a side wall of the face portion, a compressive stress layer having a thickness of at least {fraction (1/10)} of the thickness of the face portion, is formed on each of the inner and outer surfaces of a useful screen area of the face portion, so as to satisfy 0.4&lE;&sgr; /&sgr; &lE;1.0, where &sgr; is the compressive stress on the inner surface at the center of the useful screen area, and &sgr; is the compressive stress on the inner surface in the vicinity of ends of diagonal axial lines of the useful screen area.

Glass panel for a cathode ray tube

A glass panel for a cathode ray tube including a substantially rectangular face portion and a skirt portion. Further constituting a side wall of the face portion, a compressive stress layer having a thickness of at least 1/10 of the thickness of the face portion, is formed on each of the inner and outer surfaces of a useful screen area of the face portion, so as to satisfy 0.4.ltoreq..sigma..sub.di /.sigma..sub.ci .ltoreq.1.0, where .sigma..sub.ci is the compressive stress on the inner surface at the center of the useful screen area, and .sigma..sub.di is the compressive stress on the inner surface in the vicinity of ends of diagonal axial lines of the useful screen area.

Air is blowed before an annealing step to corner portions in an inner face portion of a glass panel which has been press-formed in a mold to cool that portions to be stronger than the other portion whereby a temperature difference between the corner portions and the other portion is reduced.

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Funabashi, Japan

Hiroshi Yamasaki