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:
Jan. 19, 2010
Filed:
Jun. 02, 2006
Keiichi Matsumoto, Himeji, JP;
Shoichi Terada, Himeji, JP;
Tetsu Okamoto, Himeji, JP;
Ushiodenki Kabushiki Kaisha, Tokyo, JP;
Abstract
An ultra-high pressure mercury lamp in which the tungsten comprising the electrodes is prevented from spraying during starting and operation, and blackening on the inside wall of the arc tube is prevented is achieved in that at least one of the electrodes has an axial part which is made essentially of tungsten and a starting part which is made essentially of tungsten, at least one of the axial part and of the starting part containing an electron emission material with a smaller work function than tungsten such that the value of S/A in mm/% by weight is in the range 1≦S/A≦1×10, S in mmdesignating the surface area of the part of the electrode projecting into the arc tube containing the electron emission material and A in % by weight indicating the concentration of the electron emission material in this part.