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, 1999
Filed:
Dec. 20, 1996
Tatsushi Igarashi, Tokyo, JP;
Osamu Mizuno, Mishima, JP;
Kazuo Nakamura, Kakogawa, JP;
Shoichi Mayama, Himeji, JP;
Ushiodenki Kabushiki Kaisha, Tokyo, JP;
Abstract
A discharge lamp in which ultraviolet radiation of short wavelengths can be advantageously cut and in which the amount of emitted light (i-line) of 365 nm wavelength can be increased is achieved according to the invention by providing a quartz glass arc tube that is coated with a plurality of coating layers which include a layer which has Ta.sub.2 O.sub.5 as the main component, and at least one additional coating layer which has a refraction coefficient which differs from the refraction coefficient of the coating layer having the Ta.sub.2 O.sub.5 main component. These layers act to prevent the reflection of light with a wavelength of 365 nm which is incident on the coatings on the arc tube and to cut at least 50% of the ultraviolet radiation having wavelengths of 230 nm or less. According to the invention, the coating layers can be provided on the outer side of the arc tube, on the inner side of the arc tube, or on both on the inner and outer sides of the arc tube.