Toshiba Lighting & Technology Corporation

Noriji Watanabe

Seiji Ashida

Kiyoshi Saita

Tatsuo Otabe

Masuo Shibuya

Hisahi Honda

The present invention provides a high-voltage discharge lamp having an internal volume of 0.05 cc or less that is small yet maintains a desirable lifetime and a high luminous efficiency, a high-voltage discharge lamp device using the lamp, and a lighting apparatus using the lamp. The high-voltage discharge lamp comprises a ceramic discharge vessel that has a spherical, bulging section and a pair of small diameter cylindrical sections. The spherical, bulging section surrounds a discharge space. The small diameter cylindrical sections are connected to the ends of the spherical, bulging section. Electrode-integrated power-supplying conductors are used. Each conductor comprises a seal part and a halide-resistant part. The halide-resistant part having a proximal end connected to the distal end of the seal part. The distal end of the halide-resistant part projects into the spherical, bulging section of the translucent ceramic discharge vessel forming an electrode. A narrow gap is provided between the halide-resistant part and the inner surface of the small diameter cylindrical section. A discharge medium containing a metal halide and rare gas are filled in the translucent ceramic discharge vessel. When materials having a high average linear transmittance, such as YAG, are used as light-transmitting ceramics, the luminous efficiency of a small high-voltage discharge lamp will be increased.

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Yokosuka, Japan

Noriji Watanabe