Nippon Electric Glass Co., Ltd.

Shigeyoshi Ito

Masaya Kyono

Hajime Makio

Upper end edges () of positioning reference portions () to be formed on outer walls of a funnel () for cathode ray tube are formed at distances (downwardly) toward a narrow open end () of the funnel from a maximum profile line () formed in the vicinity of a wide open end () by mold matching of forming mold at the time of press molding, thereby suppressing molding defects such as deficiency and wrinkle resulting from that glass is not completely filled, which are likely to occur in reference surfaces () of the positioning reference portions, and eliminating occurrences of small cracks caused by concentration of heat stress, which are likely to occur in the upper end edges () of the reference portions, to improve the productivity of the funnel.

CRT funnel with positioning reference portions

A funnel for a color cathode ray tube comprises a seal end surface to which a panel is sealed through a frit glass. An area occupying at least 50% of the seal end surface in a width direction is a rough surface. The rough surface satisfies conditions of 10&#x2266;Rz&#x2266;25 &#x3bc;m and 2.5&#x3c;Sm/Rz&#x2266;6.0, where Rz is the ten point height of roughness profile in the width direction and Sm is the mean interval of profile peaks and profile valleys in the width direction. The rough surface comprises a plurality of dimple-like micro cavities formed by the profile peaks and the profile valleys.

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Nagahama, Japan

Shigeyoshi Ito