Koito Manufacturing Company, Ltd.

Yukihiro Yoshida

Hiroshi Goto

Shinichi Irisawa

Takeshi Fukuyo

Kunio Fukai

Yoshihiro Mochizuki

A method of producing an arc tube including inserting an electrode assembly in which a bent portion is formed in a lead wire into a glass tube to self-hold the electrode assembly to a predetermined position of the glass tube. After the electrode has been inserted to the predetermined position, pinch-sealing is conducted on a portion of the glass tube where the assembly is inserted. In the method, the electrode assembly is inserted into a metal guide pipe which is coaxially disposed with respect to the glass tube, to be once held into the pipe. Thereafter, the assembly may be pushed by a thin rod-like pushing member to be inserted to the predetermined position in the glass tube. One or more vertical grooves which are to be axially engaged with the bent portion of the assembly to circumferentially lock the bent portion may be formed in the inner side of the guide pipe. Using the one or more grooves, the assembly may be guided to the glass tube W without being in sliding contact with the guide pipe. Therefore, in a preferable embodiment, this prevents metal powder, which may be produced by rubbing and shaving the inner side of the guide pipe with the bent portion of the lead wire, from entering the chamber portion as a foreign matter. A holding chuck is not required to insert the assembly into the glass tube, but is used to facilitate insertion of the assembly into the guide pipe. The chuck for holding the assembly is not restricted in shape. The assembly in the guide pipe is guided to the glass tube and may be restricted by the vertical grooves to be circumferentially positioned.

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Shizuoka, Japan

Yukihiro Yoshida