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:
Dec. 12, 2006
Filed:
Oct. 17, 2001
Jean-claude Lehureau, Sainte Genevieve des Bois, FR;
Jean-Claude Lehureau, Sainte Genevieve des Bois, FR;
Thales, Paris, FR;
Abstract
The invention concerns a recording medium for optically readable data of the multilayer type, a method for making same and an optical system for reproducing said data for reading the medium. The medium (Sb) comprises a stack of layers (Cto CN) whereof the interfaces constitute planes (Pto PN) bearing slightly phase-shifting information elements. Said planes generate a relatively significant disturbance of the transmitted beam while diffracting only a very small part of the light passing through them. The reading beam (FI) is focused on the bearing plane and reading is performed by transmission. The disturbances caused by the neighboring defocused layers are eliminated by far field detection of only the low spatial frequencies in the transmitted beam. The invention is particularly useful for very high capacity data optical storage.