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:
Aug. 29, 2006
Filed:
May. 21, 2003
Toshio Fukaya, Tsukuba, JP;
Junji Tominaga, Tsukuba, JP;
Toshio Fukaya, Tsukuba, JP;
Junji Tominaga, Tsukuba, JP;
Abstract
The invention discloses a flat-plate lens to be built in an optical recording medium for improving the image-forming characteristics of the recording medium. The flat-plate lens of the invention comprises a layered thin film having a periodical structure in the direction of thickness thereof corresponding to a wavelength slightly longer than the wavelength of the light used for recording and retrieving information into and from the recording medium. The thin film of a periodical structure is formed by alternate lamination of pluralities of layers two materials having different refractive indices such as a combination of MgFand ZnS. When the thin film having such a periodical structure is formed with good uniformity allover the surface, the image-forming performance on the recording layer can be uniform irrespective of the position on the flat-plate lens.