Nippon Sheet Glass Company, Limited

Chihiro Sakai

Masashi Kikuta

Masayuki Maenaka

Koji Nakanishi

Etsuo Ogino

Terufusa Kunisada

Yoshikazu Toshikiyo

Yasunori Taninaka

In a process for producing an air-quench-toughened glass plate, defective glass plates containing nickel sulfide (NiS) are removed by compulsory breaking the glass plates. Such compulsory breakage is carried out in the course of a batch-manner soaking process carried out after a toughening step; in the course of a toughening step carried out after generation of cracks in an annealing step; in the course of a toughening step carried out after generation of cracks in a pretreatment step; or in the course of a continuous annealing step carried out after a toughening step. Through the method, NiS-free toughened glass plates of high-quality can be produced.

Method for producing air-quench-toughened glass plate

The present invention provides a raw material composition for soda-lime glass capable of effectively suppressing formation of nickel sulfide (NiS) in the course of melting of the glass raw material. A nickel sulfide (NiS) impurity present in soda-lime glass is formed in a high-temperature vitrification step in which metal particles containing Ni and an Ni component of stainless steel used for the interior of a melting furnace, which are mixed into glass raw material, react at high temperature with a sulfur (S) component in Na SO serving as a glass raw material. However, when an additive containing an oxide, a chloride, a sulfate, or a nitrate of a metal is added in a very small amount and in advance to glass raw material, formation of NiS by the reaction between Ni and S in the course of melting can be suppressed or completely eliminated.

Raw material composition for soda-lime glass

In a process for producing an air-quench-toughened glass plate, defective glass plates containing nickel sulfide (NiS) are removed by compulsory breaking the glass plates. Such compulsory breakage is carried out in the course of a batch-manner soaking process carried out after a toughening step; in the course of a toughening step carried out after generation of cracks in an annealing step; in the course of a toughening step carried out after generation of cracks in a pretreatment step; or in the course of a continuous annealing step carried out after a toughening step. Through the method, NiS-free toughened glass plates of high quality can be produced.

A face panel for a cathode-ray tube is coated with an antireflection film by forming, on the outer surface thereof in this order, a 44.9 nm-thick praseodymium titanate film as a first layer, a 4.9 nm-thick film of a nickel-iron alloy as a second layer, a 53.4 nm-thick praseodymium titanate film as a third layer, a 3.9 nm-thick film of a nickel-iron alloy as a fourth layer, a 20.6 nm-thick praseodymium titanate film as a fifth layer, and an 84.7 nm-thick magnesium fluoride film as a sixth layer. This coated face panel is free from the problem that conventional cathode-ray tube face panels coated on the outer surface with an antireflection film comprising superposed metal films and transparent dielectric films make the cathode-ray tubes exhibit double images although effective in diminishing the reflection of external light on the surface of the cathode-ray tubes and in enhancing display contrast. The cathode-ray tube using the face panel coated with the specific antireflection film does not exhibit double images, is prevented from suffering static buildup on its surface or from reflecting external light thereon, and can attain higher image contrast.

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Osaka, Japan

Chihiro Sakai