Optical low pass filter
US4998800A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Apr 3, 1989 |
| Grant date | Mar 12, 1991 |
| Priority date | — |
| Expiry date | Apr 3, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B27/46
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An optical low pass filter for use in an imaging device including an objective lens and a solid state image sensor forming a plurality of picture elements thereon, which filter comprises a diffraction grating disposed between the objective lens and the solid state image sensor. The diffraction grating is of a type which the periodicity of an image of the diffraction grating projected onto the solid state image sensor by the objective lens is selected to be twice or 1/n of the periodicity of the picture element, wherein n represents an integer. The applicable imaging device may be of a type comprising an objective lens, a solid state image sensor forming a plurality of picture elements thereon, and a color filter array disposed on the solid state image snesor and including a plurality of sets of different color filter elements, or of a type comprising a single tube type color imaging device having an evacuated glass envelope, an objective lens and a color filter array including a plurality of sets of different color filter elements.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.