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. 28, 1993
Filed:
Aug. 25, 1992
Hoya Corporation, Tokyo, JP;
Dainippon Plastics Co., Ltd., Osaka, JP;
Abstract
Provided is an optical filter structure which has excellent solarization resistance, and stably gives a constant wavelength distribution and constant irradiation energy for a long time, and which efficiently cuts off infrared light including near infrared light and ultraviolet light having a short wavelength and is sufficiently permeable to visible light. The optical filter structure has a glass filter 7 formed of phosphate or fluorophosphate glass containing 0.1 to 5% by weight, as an oxide, of copper oxide and an aquafilter 6 having a liquid layer 5 measuring 3 to 50 mm as a light path length, the glass filter 7 being placed either outside a container wall, 2a or 2b, of the aquafilter 6 or within the liquid layer 5, and the optical filter structure has optical characteristics that the absorption edge on a short wavelength side is a region of light having a wavelength of 250 to 330 nm and that the maximum value of the spectral transmittance on a long wavelength side beyond 780 nm is not more than 40%.