Asahi Glass Company, Limited

The Circle for the Promotion of Science and Engineering

Mikio Ueki

Tsunehiko Sugawara

Yuichi Kuroki

Shuichi Shibata

Jaeho Lee

Tetsuji Yano

A glass funnel suitable for a chemical strengthening method of an electric field application type without impairing the safety of a cathode ray tube. A glass funnel for a cathode ray tube, characterized in that glass at a body portioncontains at least NaO and KO, the conductivity of said glass at the strain point is at least 4&#xd7;10S/cm, the conductivity at 150&#xb0; C. is at most 5&#xd7;10S/cm, and a compressive stress layer is formed by a chemical strengthening method on at least part of the outer surface of the body portion

Glass funnel for cathode ray tube, and cathode ray tube

The present invention is to obtain a glass bulb of reduced weight, and high safeness and reliability by ion exchanging which assures a compressive stress layer having an effective thickness even to a large tensile vacuum stress. For this purpose, a region in an outer surface of a body portionof the glass funnel, the region having a small mechanical strength and producing the maximum tensile vacuum stress thereby causing breakage easily, is partly strengthened by ion exchanging method according to an electric field assisting method and an ion exchanging method using paste in combination, whereby a portionstrengthened by ion exchanging method is provided in that region wherein the concentration of doped ions in a strengthened compressive stress layer is distributed according to a substantially step function in a direction from the surface of the glass toward the inside of it.

Glass bulb for a cathode ray tube and a method for producing the same

A glass funnel for a cathode ray tube, which has a substantially rectangular opened end at one end and a neck portion at the other end and which constitutes, together with a glass panel having a substantially rectangular face portion, a glass bulb to be used for a cathode ray tube, wherein the glass constituting the glass funnel contains, by molar percentage, at least 60% of SiOand at least 7% of PbO; when the molar percentages of NaO and KO contained in said glass are represented by WNa and WK, respectively, 0.35&#x2266;WK/(WNa+WK)&#x2266;0.6; a compressive stress layer is formed by chemical tempering at least in the outer surface of a region containing a position where the tensile stress formed when the interior of the glass bulb is vacuumed to produce the cathode ray tube, becomes maximum; and either one or both of the outer surface of the chemically tempered region and the inner surface opposite to said outer surface, are colored by ion exchange coloration.

Growing community of inventors

Funabashi, Japan

Mikio Ueki