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. 21, 1989
Filed:
Mar. 31, 1988
Shinichi Tsunekawa, Fujisawa, JP;
Masami Takagi, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
A rare-gas arc lamp includes a pair of coil filaments disposed at the opposite ends of an elongated bulb for increasing an area of a positive column produced between the coil filament pair in a direction perpendicular to the elongated axis of the bulb, and a rare-gas mainly including xenon gas and having substantially no mercury therein sealed in the bulb at a prescribed pressure selected from the range between 20 Torr and 200 Torr. The combination of the coil filament pair and the xenon gas sealed in the bulb at a prescribed pressure in the range of 20 Torr to 200 Torr may reduce visible changes in a luminance distribution of the lamp when the positive column fluctuates during the operation of the lamp.