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:
Sep. 29, 1998
Filed:
Jun. 05, 1997
Applicant:
Inventors:
Toshio Ohashi, Komaki, JP;
Michio Asai, Nagoya, JP;
Assignee:
NGK Insulators, Ltd., , JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01N / ;
U.S. Cl.
CPC ...
2504 / ; 250428 ;
Abstract
A gas tube for passing plasma generating gases, having high UV transmittance and corrosion resistance against corrosive gases is disclosed. The tube is composed of a longitudinally extended throughhole and a thin circumferential wall and is provided with a means for radiating UV rays directed to an upstream portion thereof from outside. The wall is formed of a light-pervious alumina ceramic, and has a center-line mean roughness (R.sub.a) of not more than 1.0 .mu.m in a portion exposed to gas plasma.