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. 02, 1999
Filed:
Feb. 09, 1998
Yukio Yasuda, Himeji, JP;
Masanori Sugihara, Himeji, JP;
Ushiodenki Kabushiki Kaisha, Tokyo, JP;
Abstract
A mercury lamp of the short arc type with a high degree of maintenance of irradiance is achieved in a mercury lamp of the short arc type by the cathode containing thorium oxide and having a tungsten carbide layer on its surface except at tip end area, by at least one of the cathode or anode being provided with metallic tantalum, and by the condition 1.56.ltoreq.VT/SC being satisfied, where SC is the area of the tungsten carbide layer (cm.sup.2) and VT is the volume of the metallic tantalum (mm.sup.3). Alternatively, a high degree of maintenance of irradiance can be achieved in a mercury lamp of the short arc type by the condition 0.043.ltoreq.VT/VW being satisfied, where VW is the volume of the anode (cm.sup.3) and VT is the volume of the tantalum in the lamp bulb (mm.sup.3).