Koito Manufacturing Company, Ltd.

Nobuo Ohkawai

Shinichi Irisawa

Yoshitaka Ohshima

Takeshi Fukuyo

Masakazu Nagasawa

Goichi Oda

Akihiro Nagata

Kunio Fukai

Yukio Wakimizu

Masaya Shidoh

A method of manufacturing an arc tube having a light emitting tube portion, a first pinch seal portion, and a second pinch seal portion, all formed on a quartz glass tube. The first and second pinch seal portions are disposed on both sides of the light emitting tube portion. The quartz glass is provided almost vertically with the first pinch seal portion down. A thermal insulating plate is provided in a boundary position between the light emitting tube portion and a portion to be pinch-sealed in an outer peripheral space of the quartz glass tube. Liquid nitrogen is jetted from a cooling nozzle provided obliquely below the light emitting tube portion toward the same, thereby cooling the light emitting tube portion. The portion to be pinch-sealed is heated with a burner, and pinch-sealed with a pincher immediately thereafter.

Method of manufacturing arc tube

A method of manufacturing an arc tube for a discharge lamp unit, incorporating a primary pinch-sealing step for mounting an electrode assembly in an open end of a glass tube W with a chamber portion . The electrode assembly comprises an electrode rod , a connecting foil and a lead wire integrally connected in series. The electrode assembly is inserted into an open end of the glass tube W such that a leading end of the electrode rod projects into the chamber portion . A temporary pinch seal region L of the glass tube W is pinch-sealed such that a portion of the connecting foil that is connected to the lead wire is contacted by the glass tube W. A vacuum is maintained inside the glass tube and a main pinch seal region L of the glass tube is pinch-sealed such that a portion of the connecting foil connected to the electrode rod is contacted by the glass tube. When the main pinch seal region L of glass tube W is pinch-sealed, the negative pressure in the glass tube W is exerted on the softened sealed chamber portion owing to supplied heat as well as the pressure exerted from the pincher . Thus, the glass layer is pressed against the surface of the molybdenum foil so that hermetic contact is realized.

ARC tube for discharge lamp unit and method of manufacturing same

An arc tube provided with a central sealed chamber , in which light-emitting substances are enclosed, having a pair of electrode assemblies disposed opposite to each other. The electrode assemblies are sealed in pinch seal portions . The arc tube incorporates a residual-compressive-stress layer formed on a surface of the glass layer in each of the pinch seal portions that contacts the electrode rod included in each electrode assembly. The residual-compressive-stress layer has a length greater than or equal to 30% of the axial length of a glass layer region that only contacts the electrode rod and/or an angular range greater than or equal to 180&deg; in a circumferential direction of the electrode rod. Thermal stress (tensile stress) produced in the boundary between the glass layer and the electrode rods after the arc tube has been turned on is absorbed and dispersed by the residual-compressive-stress layer surrounding the electrode rods . Thus, any vertical crack that would result in the light-emitting substances leaking from the sealed chamber does not form in the glass layer of the pinch seal portions

Arc tube with residual-compressive-stress layer for discharge lamp unit and method of manufacturing same

Arc tube for discharge lamp device and method of manufacturing the same

The pinch-sealing for the first one of a pair of molybdenum foils is not performed by flowing inactive gas within a quartz glass tube like the prior art but performed in a manner that the lower end portion of the quartz glass tube is sealed, and then and a pinch seal estimation portion is squeezed by a pincher while air within the quartz glass tube is exhausted from the upper end portion thereof so that pressure within the quartz glass tube becomes in a negative pressure state of 100 torr or less and while heating the pinch seal estimation portion Accordingly, at the time of the squeezing, the inner wall surface of the pinch seal estimation portion thus heated is attracted to the molybdenum foil side thereby to form fine concave and convex portions on the interfaces between the molybdenum foil and the quartz glass tube so that the molybdenum foil and the quartz glass tube are placed in an engaged state and the contact area therebetween is increased.

Arc tube and fabricating method thereof

A discharge lamp arc tube comprises: a glass tube having a linear extension portion, a closed glass bulb, and pinch seal portions at both sides of the closed glass bulb; and electrode assemblies, each having an electrode rod, a molybdenum foil and a lead wire integrally series-connected, the molybdenum foil having oxide films thereon, wherein the electrode assemblies are inserted into the glass tube and pinch-sealed such that the molybdenum foils are positioned at the respective pinch seal portions.

Discharge lamp arc tube and method of producing the same

A metallic halide lamp has an envelope of silica glass defining a discharge chamber with a pair of pinch seals extending in opposite directions therefrom. A pair of tungsten electrode stems are partly buried in the respective seals and electrically connected to a pair of molybdenum lead wires via a pair of molybdenum foils which are wholly embedded in the pinch seals. The molybdenum foils have a recrystallization grain size of not more than about 50 .mu.m.

Molybdenum foils with yttrium oxide and recrystallization grains no more

The invention is directed to preventing occurrence of molybdenum foil breakage during a pinch sealing operation in a method of fabricating an arc tube having a pair of molybdenum foils pinch-sealed on both sides of a spherical portion of a glass tube by sequentially pinch-sealing the respective molybdenum foils. A first molybdenum foil is not pinch-sealed (first pinch seal) with an inert gas introduced into a glass tube as in a conventional embodiment, but is pinch-sealed with the internal pressure of the glass tube maintained at a vacuum of 0.5 torr or less. As a result, oxidation of the molybdenum foils causing breakage of the molybdenum foils during a pinch sealing operation is minimized. Hence, an arc tube having each of a pair of molybdenum foils made of molybdenum whose purity is 99.95% or more and with a thickness of 20 .mu.m or less can be fabricated.

Arc tube having a pair of molybdenum foils, and method for its

An electric discharge lamp assembly including a lamp bulb having two lead wires, and a lamp base supporting two lead support members with respective tip ends thereof being connected respectively to the lead wires of the lamp bulb. One of the lead support members is formed to have an elongated length and is covered by an insulating tubular member substantially. The rear end portion of the insulating tubular member is fitted on and secured to a tubular portion of the lamp base which portion is integrally formed with the lamp base. Whereby the electric discharge between the two support members is prevented effectively, and the insulating tubular member is secured to the lamp base reliably.

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Shizuoka, Japan

Nobuo Ohkawai