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. 13, 2007
Filed:
Dec. 14, 2006
Munetoshi Yoshikawa, Chichibu, JP;
Kazuo Suzuki, Chichibu, JP;
Takayuki Wakabayashi, Chichibu, JP;
Masayuki Uchiyama, Honjo, JP;
Munetoshi Yoshikawa, Chichibu, JP;
Kazuo Suzuki, Chichibu, JP;
Takayuki Wakabayashi, Chichibu, JP;
Masayuki Uchiyama, Honjo, JP;
Canon Denshi Kabushiki Kaisha, Chichibu-Shi, JP;
Abstract
This invention decreases deformation of a plastic substrate caused by thermal expansion and contraction in an evaporation process of forming a multi-layered film of an ND filter, thus helping prevent wrinkles. The plastic substrate serving as the base of the ND filter is made of a polyimide-based plastic material having a glass transition temperature of 200° C. or more, has a total transmittance of light of 90% or more, and has a haze factor of 0.5% or less. As the multi-layered film, AlOfilms for reduction of the reflectance and TiOfilms for reduction of the transmittance are alternately formed on the substrate.