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:
Aug. 09, 1994
Filed:
Apr. 13, 1993
R Russel Austin, Novato, CA (US);
Photran Corporation, Lakeville, MN (US);
Abstract
A visible light transmitting, near-infrared reflecting filter for a substrate, comprises a central group of layers (26) including two metal layers (32 and 36) separated by a spacer-layer (34) and bounded by admittance-matching layers (32 and 38). The spacer-layer has an optical thickness of less than one-half wavelength of visible light and the admittance-matching layers have an optical thickness of less than one-quarter wavelength of visible light. On each side of the central group is a group of layers (24 and 28) for boosting near infrared reflectivity of the filter, and for providing low reflection and high transmission for visible light. Each of these near-infrared-reflection-boosting groups including a high refractive index layer (40 and 42) and at least one low refractive index layer (46 and 48). The high index layer has an optical thickness of about one-quarter wavelength at a near-infrared wavelength, and the low refractive index layer has a refractive index of less than one-quarter wavelength at the near-infrared wavelength.