Toshiba Lighting & Technology Corporation

Sadao Sakaguchi

Hisashi Honda

Seiji Ashida

Kazuyoshi Okamura

Miho Watanabe

Ryo Kikuta

Masazumi Ishida

Takahito Kashiwagi

Shigemi Oku

Kazuhiro Miyagawa

Shigehisa Kawatburu

Yasuhito Fujita

Akihiro Kanda

A high-pressure discharge lamp which includes a translucent ceramic discharge vessel having a swollen portion defining a discharge space and a pair of cylindrical portions formed in and communicating with the swollen portion and extending from the swollen portion in the opposite directions with each other. The high-pressure discharge lamp also includes metal tubes each having a outer diameter D and fit with its one end on the cylindrical portion, a pair of fusible metal plugs each plugged in the outer end of the metal tube, the fusible metal plug sealing the discharge vessel by being fused to the inner surface of the metal tube for a specified height T from the outer end of the metal plug, a pair of electrode systems each supported its one end to the fusible metal plug and facing the interior of swollen portion with its other end, and ionizing filling filled in the discharge vessel The ratio T/D of the height T concerning the fusible metal plug and the diameter D satisfies the following equation 0.40&lE;T/D&lE;0.95.

High pressure discharge lamp and luminaire

The invention provides the high-intensity discharge lamp and the high-intensity discharge lamp lighting system and the lighting system using the high-intensity discharge lamp showing the low enough starting voltage. The high-intensity discharge lamp comprising a lighting-source bulb provided with an enclosure, a light-transmissive ceramic enclosure defining a pair of small-diameter cylinders communicating with the enclosure at both ends thereof, a pair of electrodes and discharge agent, a metallic coil which is wound on the outside surface of at least one small-diameter cylinder and coupled to the other end of the electrode to have the same potential with the electrode, a jacket-bulb which hermetically accommodates therein the lighting-source bulb and the metallic coil, and a pair of outer lead terminals which are coupled to the pair of electrodes and hermetically led outside the jacket-bulb. The metallic coil is preferably wound for four turns or more on the small-diameter cylinder, and placed its one end near the boundary to the enclosure of the light-transmissive ceramic discharge enclosure, and the winding pitch of the metallic coil resides in the range of 100% to 500%. Further, the length L of the metallic coil is 0.3 to 1.0 times the length of the small-diameter cylinder. Furthermore, the end of it which is opposite to the enclosure is coupled to have the same potential as the other electrode.

High-intensity discharge lamp, system for lighting the lamp and lighting appliance using the lamp

Lamp bulb

Growing community of inventors

Kanagawa-ken, Japan

Sadao Sakaguchi