Iwasaki Electric Co., Ltd.

Katsuhiro Okabe

Makoto Ohkahara

Nobuo Fukuda

Toshio Yoshizawa

Shinichi Takemasa

Shigeharu Sato

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.

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Gyoda, Japan

Katsuhiro Okabe