Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Matsushita Industrial Co., Ltd.

Akio Takubo

Masato Wada

Shunsuke Kakisaka

Atsushi Utsubo

Yukiya Kanazawa

Masahito Yoshida

Akira Mii

A lamp having: an arc tube () including a main tube portion and a pair of thin tube portions () provided at ends of the main tube portion; and an adjacent conductor () including a strip-shaped metal plate. In the adjacent conductor (), a portion of the metal plate in the direction of length thereof, from the middle of the metal plate to just before an edge thereof, is a gripping portion () having a shape suitable for gripping the outer circumferential of one of the thin tube portions (). One end of the gripping portion () is a free end. The gripping portion () is disposed along an outer circumferential surface of the thin tube portion () so as to be in contact with the outer circumferential surface, and is elastically deformable in accordance with expansion in the radial direction of the thin tube portion ().

High-intensity discharge lamp

A high pressure discharge lamp is provided with an arc tube and a starter. The starter includes a ferroelectric ceramic capacitor element with non-linear characteristics an a semiconductor switching element, connected in parallel to the arc tube. A pulse stopping thermally-actuated switch is connected in series to the ferroelectric ceramic capacitor element and is operated to OFF by heating of a heating resistor in a non-lighted state of the lamp. Without accompanying reduction of a starting function due to a temperature rise of the ferroelectric ceramic capacitor element, a safety function against a non-lighted state of the lamp is provided.

High pressure discharge lamp

An electrode is fixed hermetically to one end of a conductive tube with a titanium solder and the other end of the conductive tube is closed. Thus, the conductive tube has an airtight structure and an argon gas is sealed therein. This conductive tube is fixed hermetically to a transparent alumina tube using a sealer. Further, sodium amalgam is provided at an inner end of the transparent alumina tube. The conductive tube is prevented from being deformed and sodium of a luminescent material is positioned inside the discharge tube, thus providing a high-pressure sodium lamp in which a lighting color and lamp voltage are prevented from varying during the lamp lifetime, the time required for reaching a stable lighting state after turning on the lamp is short, and the variation in lamp voltage is suppressed.

High-pressure sodium lamp

Growing community of inventors

Osaka, Japan

Akio Takubo