Iwasaki Electric Co., Ltd.

Toshio Yoshizawa

Makoto Ohkahara

Nobuo Fukuda

Atsushi Ohno

Yasuhisa Matsumoto

Yoshiaki Kuroda

Shinichi Takemasa

Shigeharu Sato

Junpei Nishimura

Katsuhiro Okabe

Shingo Yamamoto

A high pressure discharge lamp of the present invention is provided with a light-emitting bulb comprising a light-emitting part and sealing sections; metal foils embedded within the sealing sections; and a pair of electrodes having one end protruding into the light-emitting part and having the other end embedded in the corresponding sealing section and joined to the corresponding metal foil. An embedded length L (mm) of the electrodes that is defined by the length between a light-emitting part side end of the metal foil and the border section between the protruding section and the embedded section of the electrode, and the temperature T (&#xb0; C.) at the joint region of the electrode and the metal foil are set to satisfy 1.8&#x2266;L&#x2266;2.8 and T&#x2266;970.

High pressure discharge lamp

Provided is a manufacturing method to prevent devitrification of a bulb in a high pressure discharge lamp used for a projector. The method is for manufacturing a high pressure discharge lamp which uses, as a light source, a bulb made of fused quartz and including a tungsten electrode, and which is horizontally installed when the lamp is driven for actual use. The method includes the step of initially driving the bulb with an optical axis thereof being set horizontally before the high pressure discharge lamp is shipped. In the initial driving step, the rotation angle around the optical axis of the bulb is offset by 45&#xb0; or more and 135&#xb0; or less relative to the rotation angle around the optical axis of the bulb when the lamp is driven for actual use.

Method for manufacturing high pressure discharge lamp

Provided is an electrode for a high pressure discharge lamp, which prevents spring-back of an electrode coil, and which has high productivity and high accuracy in positioning the coil. The electrode for the high pressure discharge lamp includes: an electrode core bar (); and a coil () mounted on the electrode core bar, and is configured as follows. The electrode core bar () includes: a small-diameter section () on a power supply side; and a large-diameter section () on a leading end side. The large-diameter section () has: a large-diameter portion () on the small-diameter section side; a small-diameter portion () having a smaller outer diameter than the large-diameter portion, the small-diameter portion forming a step (s) with the large-diameter portion therebetween; and a leading end portion (). The coil () covers a portion between the step (s) and the leading end portion.

Electrode for high pressure discharge lamp, high pressure discharge lamp, and method for manufacturing electrode for high pressure discharge lamptechnical field

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Gyoda, Japan

Toshio Yoshizawa