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:
Apr. 25, 1995
Filed:
Jun. 01, 1993
William H Southwell, Thousand Oaks, CA (US);
Rockwell International Corporation, Seal Beach, CA (US);
Abstract
A multiple pass band, thin film optical filter includes a first single pass band filter having a first pass band at a first wavelength, with a first quarterwave stack of thin film layers alternating between layers of a first dielectric material having a first refractive index and layers of a second dielectric material having a second refractive index, the optical thickness of each layer in the first stack being substantially one fourth of the first wavelength. A first half wave layer is interposed within the first stack and has an optical thickness which is an integral multiple of one half of the first wavelength, such that the reflectivities of the portions of the first stack on either side of the first half wave layer are substantially identical. A second single pass band filter having a second pass band at a second wavelength, includes a second quarterwave stack of thin film layers alternating between layers of the first dielectric material and layers of the second dielectric material, the optical thickness of each layer in the second stack being substantially one fourth of the second wavelength, and a second half wave layer interposed within the second stack having a thickness which is an integral multiple of one half of the second wavelength, such that the reflectivities of the portions of the second stack on either side of the second half wave layer are substantially identical. The first and second single pass band filters are combined in series to provide a filter with a pass band at the first wavelength and a pass band at the second wavelength.