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. 05, 2013
Filed:
Jan. 27, 2011
Akihiro Shimizu, Himeji, JP;
Tomoyoshi Arimoto, Himeji, JP;
Mitsuru Ikeuchi, Himeji, JP;
Ushio Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A discharge lamp with excellent arc stability and excellent durability in which the use level of thoriated tungsten is restrained has an anode and a cathode in the interior of a discharge vessel, wherein said cathode is made up from a thoriated tungsten part with a tungsten filling ratio of at least 90 vol.-% and a main body part connected to said thoriated tungsten part and consisting of pure tungsten, wherein a ratio S/S of a side surface area Sof said thoriated tungsten part and a side surface area S of said cathode is in a range of from 0.005 to 0.15, with the proviso that, in case the cathode has a length in the direction of the cathode axis which exceeds twice the maximum diameter of the cathode, a side surface area S is used for calculating the ratio S/S which corresponds to the side surface area where the distance along the cathode axis from a tip end adjacent to the anode is twice the maximum diameter of the cathode.