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. 06, 1993
Filed:
Jul. 12, 1991
William A Meredith, Jr, Santa Rosa, CA (US);
Paul M LeFebvre, Santa Rosa, CA (US);
Optical Coating Laboratory, Inc., Santa Rosa, CA (US);
Abstract
High purity (95-99.5 percent) red, orange and yellow filters are disclosed which comprise a periodic stack of relatively low index of refraction dielectric material (L) such as SiO.sub.2 or MgF.sub.2 and absorbing relatively high index material such as silicon or Fe.sub.2 O.sub.3. Together, the low and high index materials provide a high index ratio (typically 1.7 to 2.5). The filters are fabricated according to designs such as (H/2 L H/2).sup.n, typically using only 5 to 7 layers. Despite the very small layer count, these filters provide overall optical performance which is at least the equivalent of all-dielectric filters of 30 or more layers, with color purity that is unachievable by all-dielectric filters and simple low cost design. In addition, our filters have inherently low stress levels and absorb and reflect unwanted light such as blue light. As a consequence, the filters are ideally suited for coating on flexible substrates such as plastics and for coating on lamp envelopes to form red or yellow bulbs which are ideally suited, for example, for use as automobile tail light bulbs, side marker bulbs and turn signal bulbs.