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:
Nov. 09, 2004
Filed:
Sep. 23, 2002
Michio Takagaki, Shizuoka, JP;
Shinichi Irisawa, Shizuoka, JP;
Koito Manufacturing Co., Ltd., Tokyo, JP;
Abstract
A mercury-free arc tube having a closed glass bulb held between pinch seal portions located at opposite ends of the closed glass bulb and a pair of electrodes provided in the closed glass bulb. The closed glass bulb does not contain mercury (Hg), but contains a main light emitting, a buffer metal halide, and a starting rare gas enclosed in the closed glass bulb. The buffer metal halide includes a halide selected from halides of Ta, Th, Cu, Rb, Nb and Pd. Preferably, at least one of the halides is Ta, Cu, Rb or Nb. The halides serve as a buffer substance and a light emitting substance in substitution for the mercury, and have an ionization potential of about 5 to 8.5 eV and excitation potential of about 4.5 eV or less having emission spectrum in a visible range, and are sealed with the rare gas.