Matsushita Electric Industrial Co., Ltd.

Mikio Miura

Nobuyoshi Takeuchi

Hiroshi Nohara

Atsushi Utsubo

Yukiya Kanazawa

Yoshiharu Nishiura

Shunsuke Kakisaka

Hiroshi Enami

Masanori Higashi

Tatsuo Nishimoto

Arc tube for a high intensity discharge lamp

Arc tube

A metal vapor discharge lamp, comprises: a translucent ceramic envelope, the envelope comprising a center bulb for defining a discharge space and side tubes, the center bulb and the side tubes being integrally molded; a pair of current suppliers extending through hollows of the side tubes respectively, each of the current suppliers comprising an electrode and a lead-in wire, a first end of the electrode being disposed in the discharge space, a second end of the electrode being connected with the lead-in wire; a sealant for hermetically sealing open ends of the side tubes; and a light-emitting metal contained in the discharge space. An inner wall and an external wall of a seamless boundary portion between the center bulb and each of the side tubes have the smallest curvature radius of Rmm and Rmm, respectively. The center bulb has an inner diameter of D mm. The lamp has an electric power of P watts. The radius R, radius R, diameter D and electric power P satisfy,&#x2212;0.00076+0.304&#x2266;&#x2266;&#x2212;0.00076+0.490, &#x2003;&#x2003;Formula (1)where P&#x2266;350 watts; and1.28&#x2266;1.39. &#x2003;&#x2003;Formula (2)

Metal vapor discharge lamp having configured envelope for stable luminous characteristics

A metal vapor discharge lamp including an arc tubethat includes a containerand power transmission membersand. The container, made of translucent ceramic, is divided into a main tube portionand narrow tube portionsandextending out from both ends of the main tube portion. The power transmission membersandrespectively include electrode pinsandmade of tungsten. Coilsandmade of tungsten are respectively wound around ends of electrode pinsand, which are respectively joined with electrode supporting membersandmade of conductive cermet. Electrode length Lis set to (0.041P+0.5) mm to (0.041P+8.0) mm, 'P' representing a lamp power in watts. Alternatively, a narrow tube portion length Lis set to (0.032P+3.5) mm to (0.032P+8.0) mm inclusive.

Metal vapor discharge lamp and lighting apparatus capable of stable maintenance of characteristics

A metal halide lamp includes: an arc tube having a light-emitting unit forming a discharge space therein, and two thin-tube units fitted into openings in both ends of the light-emitting unit; two electrode holding members provided through the thin-tube units so that one ends hold the electrodes and the other ends extend from one ends of the thin-tube units not facing the discharge space, and sealed to the thin-tube units via sealing members; and a metal tubular member through which the electrode and/or electrode holding member is inserted within the thin-tube units. Expressions &ldquo;X&gE;0.0056P&plus;0.194&rdquo; and &ldquo;0&lE;L&lE;0.44X&rdquo; are satisfied, where &ldquo;P&rdquo; is lamp wattage &lsqb;W&rsqb;, &ldquo;X&rdquo; distance &lsqb;mm&rsqb; from one end of the thin-tube unit facing the discharge space to one end of the coil facing the thin-tube unit, and &ldquo;L&rdquo; length &lsqb;mm&rsqb; of a part of the tubular member protruding into the discharge space.

Metal halide lamp with reduced change in color temperature

Growing community of inventors

Takatsuki, Japan

Mikio Miura