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:
Nov. 14, 1995
Filed:
Nov. 03, 1993
Ikuo Ohnishi, Kurashiki, JP;
Katsuya Fujisawa, Kurashiki, JP;
Kuraray Co., Ltd., Kurashiki, JP;
Abstract
To effectively cut off false signals and false color signals which would occur in an imaging device and also to suppress a reduction in quality of images which would result from a generation of a ring-shaped flare, an optical low pass filter comprises a transparent substrate having first and second surfaces opposite to each other. The optical low pass filter is adapted to be disposed between a photo-taking lens and a solid-state imaging element with the first surface confronting the solid-state imaging element. The first surface of the transparent substrate is formed with a diffraction grating. The transparent substrate used in the optical low pass filter is so designed and so structured as to have a thickness (mm) which satisfies the equation, 2.multidot.g.multidot.tan (.theta.1)+2.multidot.t.multidot.tan (.theta.c)<0.9, wherein g represents the distance of spacing between the first surface of the transparent substrate and an image plane of the solid-state imaging element; .theta.c represents the critical angle at the second surface of the transparent substrate; and .theta.1 represents the angle of emission of a first-order diffracted light which takes place when light passing through the transparent substrate is incident on the first surface at the critical angle .theta.c.