The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 25, 2008
Filed:
Dec. 20, 2004
Shunsuke Kakisaka, Osaka, JP;
Hiroshi Nohara, Hyogo, JP;
Atsushi Utsubo, Osaka, JP;
Yukiya Kanazawa, Osaka, JP;
Shunsuke Kakisaka, Osaka, JP;
Hiroshi Nohara, Hyogo, JP;
Atsushi Utsubo, Osaka, JP;
Yukiya Kanazawa, Osaka, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
he present invention aims at providing a metal halide lamp having a configuration to achieve the following goals: to prevent the lamp from burning out during the life due to a rise in lamp voltage; and to obtain high luminous efficiency at the same time. The metal halide lampcomprises: an arc tubemade of translucent ceramic and having a main tube partin which a pair of electrodesis disposed; and an outer tubehousing the arc tubetherein. 4.0≦L/D≦10.0, where L (mm) is a length of a space between the electrodesand D (mm) is an internal diameter of the main tube part. R/r ≧3.4, where R (mm) is an internal diameter of the outer tubeand r (mm) is an external diameter in the main tube partof the arc tube, within a region positionally corresponding to, in a radial direction of the outer tube and the arc tube, the space between the electrodes, on a cross-sectional surface where an outer circumference of the arc tubecomes closest to an inner circumference of the outer tube. M≦4.0, where M (mg/cc) is a density of mercury enclosed in the arc tube