JPH0463448B

• Main Authors: YANO NORIO, ISAKA AKIRA, ISHIGURO GINYA, KOTANI JUZO
• Format: Patent
• Language: English
• Published: 09.10.1992
• Subjects: BOOK COVERS; BOOKBINDING; CALCULATING; COMPUTING; COUNTING; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDEDFOR; FILES; HANDLING RECORD CARRIERS; INFORMATION STORAGE; INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER; LOOSE LEAVES; MOVABLE-STRIP WRITING OR READING APPARATUS; PERFORMING OPERATIONS; PHYSICS; PRESENTATION OF DATA; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITYFEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOTOTHERWISE PROVIDED FOR; RECOGNITION OF DATA; RECORD CARRIERS; SPECIAL PRINTED MATTER; TRANSPORTING

PURPOSE:To keep security of true information by shielding the information written on a magnetic film for magnetic recording and reproduction with a secrecy magnetic protecting film provided onto the film, providing the magnetic film with a high coercive force onto the shield film and writing false information thereon. CONSTITUTION:A PET of 150-300mum thick is used for a substrate 1, a magnetic film 2 with 1,500-30,000e of coercive force and nearly 6mu of thickness is formed thereon and then a secrecy protection film 3 having >=30Oe of coercive force and nearly 10mu of the thickness is formed. Moreover, a magnetic film 5 of 500-10,000e of coercive force and several mu thickness is formed thereon. Since the information written on the magnetic film 2 is shielded by the secrecy protecting film 3 in this magnetic card, only the false information written on the magnetic film 5 appears by a conventional method such as a magnetic pattern observing device. Since the magnetic film 5 has a function not different from the magnetic card used so far, the presence of the magnetic film 2 is not recognized.