Matsushita Electric Industrial Co., Ltd.

Takeshi Saitoh

Kazuhisa Tanaka

Tomoyuki Seki

Hideaki Kiryu

Masaru Ikeda

Kenji Mukai

Tetsuji Takeuchi

A discharge lamp comprising an arc tube containing a pair of electrodes in a light-emitting portion and an outer tube that envelops the light-emitting portion and is at least partly fused to the arc tube, wherein the outer tube comprises silicon dioxide in the range from 90 to 99.88 wt. % and boron in the range from 0.12 wt. % or more. The discharge lamp can inhibit the arc tube from deforming when the outer tube and arc tube are fused to each other by adjusting a softening temperature of the outer tube to an appropriate temperature and can realize a high accuracy of luminous intensity distribution.

Discharge lamp with outer tube comprising silicon dioxide and boron

A lamp comprises a glass substrate and a shading film. The shading film is formed by applying a greensheet comprising an inorganic pigment and an inorganic matrix compound to a surface of the glass substrate and then, firing the greensheet. The formed shading film has a portion whose thickness is 90% or more of the maximum thickness of the shading film within the range of 0.5 mm from an edge of the shading film.

Lamp with shading film

A discharge lamp for an automobile headlight has a light color that lies in a region common to the following three regions: a region bounded by an ellipse with a color point (u, v)&equals;(0.224, 0.331) as a center thereof, a major axis of 0.080, a minor axis of 0.024, and an angle from a u axis of 35 degrees in the CIE 1960 UCS diagram; a region bounded by an ellipse with a color point (u, v)&equals;(0.220, 0.332) as a center thereof, a major axis of 0.060, a minor axis of 0.022, and an angle from a u axis of 15 degrees in the CIE 1960 UCS diagram; and a region bounded by an ellipse with a color point (u, v)&equals;(0.235, 0.335) as a center thereof, a major axis of 0.060, a minor axis of 0.030, and an angle from a u axis of 30 degrees in the CIE 1960 UCS diagram. The light color lies in a range on a side of color temperature lower than an isotemperature line of a correlated color temperature of 3800K and higher than an isotemperature line of a correlated color temperature of 3400K in the CIE 1960 UCS diagram.

Discharge lamp for automobile headlight and the automobile headlight

A greensheet comprising an inorganic pigment and an inorganic matrix component is applied to a surface of a glass substrate and fired for fixing. The formed shading film has a portion whose thickness is 90% or more of the maximum thickness of the shading film within the range of 0.5 mm from an edge of the shading film. Thus, a shading film that has distinct end faces and has an excellent thickness uniformity can be formed with a good positional accuracy. Therefore, a lamp having a highly precise light distribution property can be obtained. In addition, a lamp having such a property can be obtained with a few steps and at a low cost.

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Hyogo, Japan

Takeshi Saitoh