Variable optical filter and a wavelength-selective sensor based thereon
US9261634B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 28, 2014 |
| Grant date | Feb 16, 2016 |
| Priority date | — |
| Expiry date | Apr 20, 2034 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01J2003/1239
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A variable optical filter is disclosed including a bandpass filter and a blocking filter. The bandpass filter includes a stack of alternating first and second layers, and the blocking filter includes a stack of alternating third and fourth layers. The first, second and fourth materials each comprise different materials, so that a refractive index of the first material is smaller than a refractive index of the second material, which is smaller than a refractive index of the fourth material; while an absorption coefficient of the second material is smaller than an absorption coefficient of the fourth material. The materials can be selected to ensure high index contrast in the blocking filter and low optical losses in the bandpass filter. The first to fourth layers can be deposited directly on a photodetector array.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.