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. 04, 1997
Filed:
Aug. 22, 1995
Joern Dierks, Berlin, DE;
Juergen Maier, Berlin, DE;
Abstract
To essentially eliminate short ultraviolet (UV) radiation from a mercury high-pressure short-arc discharge lamp, that is, wavelengths below the radiation band of 365 nm, the lamp includes a discharge vessel of quartz glass which is coated with a selectively reflective outer coating (2a) and, at the inside, with a selectively absorbing inner coating (2b). The outer coating (2a) is formed by a multi-layer interference reflection filter which preferentially reflects wavelengths between about 240 and 300 nm with a filter cut-off, corresponding to 50% transmission, in the wavelength region between about 290 and 330 nm. The inner coating (2b) is a titanium dioxide coating which, preferentially, absorbs radiation below about 250 nm, with a 50% transmission at about 240 nm. In accordance with a preferred feature of the invention, a radiation absorbing titanium dioxide/silicon dioxide mixed-layer coating (2c) is applied at the outside over the multi-layer interference reflection filter (2a). The outer absorbing coating preferentially absorbs radiation below about 280 nm. Preferably, the multi-layer interference reflection filter is formed by at least 8 alternating ZrO.sub.2 and SiO.sub.2 individual layers; all the coating layers preferably have thicknesses between about 30 and 50 nm.