Ushio Denki Kabushiki Kaisha

Toshiyuki Okamoto

Yukiharu Tagawa

Akihiko Sugitani

Tetsu Takemura

Keisuke Ohkubo

Hidetoshi Ichinose

In a foil sealed lamp, a lamp container made of transparent material, has at least one sealing portion made of molybdenum wherein a metallic foil is buried, a light emitting section which is connected to one end of the metallic foil and a lead rod extending outward and connected to other end of the metallic foil, and wherein, in the sealing portion, a gap formed around a circumference portion of the lead rod is filled with sealing agent made of rubidium oxide or cesium oxide, and glass having boron oxide and bismuth oxide as principal components is coated on an outer end surface of the sealing portion so as to close the gap.

Sealing agent for a foil sealed lamp

A method for producing a fused silica envelope for use in a discharge lamp in which the inner surface of a fused silica tube is coated with a formulation containing titanium alcoholate and the coating treated by the steps including baking at a temperature of at least 1720.degree. C. to cause TiO.sub.2 to diffuse into the tube. The method results in a Ti concentration in a range of 1 .mu.m-10 .mu.m from the inner surface of the wall of the envelope is 0.5%-7% in terms of TiO.sub.2 and the product of the overall average Ti concentration and the thickness of the wall of the envelope ranges from 3.7% .mu.m to 42% .mu.m. During the baking step, the tube is shaped to include a bulb-like portion by inflating the silica tube.

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Hyogo, Japan

Toshiyuki Okamoto