MAGNETIC RECORDING MEDIUM WITH LIGHT DIFFRACTION STRUCTURE

摘要

PROBLEM TO BE SOLVED: To make forgery and alteration difficult by laminating a transparent light diffraction structure and a reflection type light diffraction structure on a substrate of a magnetic recording medium having a magnetic recording layer. SOLUTION: A magnetic recording layer 3 is buried in the upper surface of a substrate 2 in such a manner that the surfaces of the magnetic recording layer 3 and the substrate 2 lie on the same plane and a transparent light diffraction structure 4 is laminated over the entire surface of the substrate 2 including the magnetic recording layer 3. And further, a reflection type light diffraction structure 5 is laminated over a part of the transparent light diffraction structure 4. The magnetic recording layer 3 may be buried in the lower surface of the substrate 2 and the two layers may be buried in one surface or both surfaces. And the magnetic recording layers 3 may not be buried but stuck on the surface of the substrate 2 to be protruded. The transparent light diffraction structure 4 may be laminated on the surface of the substrate 2 leaving a margin of the surface and the trasnaprent light diffraction structure 4 and the reflection type light diffraction structure 5 may be laminated on the lower surface of the substrate 2.