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. 08, 2005
Filed:
Nov. 17, 2000
Shingo Hayakawa, Yokohama, JP;
Shingo Hayakawa, Yokohama, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
If the thickness of a birefringence plate that forms an optical low-pass filter is not appropriately set, problems in terms of optical characteristics or machine works are posed. Hence, there is provided an optical low-pass filter which has at least one birefringence plate which is made of a uniaxial single crystal that causes birefringence of incoming rays, has a refractive index difference of 0.02 or more for ordinary and extraordinary rays, and satisfies one of:10°<θ<30°   (1)60°<θ<80°   (2)where θ is the angle the optic axis of the birefringence plate makes with the normal to the surface of the birefringence plate.