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Browse Prior Art Database

Information Card and Reader

IP.com Disclosure Number: IPCOM000041639D
Original Publication Date: 1984-Feb-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Double, GP: AUTHOR

Abstract

Information card 10 carries a specularly reflective magnetizable stripe 11 that is covered by a thin dielectric film 12. Information can be recorded on and read from stripe 11 magnetically, using conventional magnetic techniques. In addition, information can be optically recorded on stripe 11 by forming small regions with different reflectivity, such as holes. Furthermore, high density magnetic information can be recorded using the Curie Point writing technique. That is, a small region of the stripe is heated to the Curie Point and allowed to cool in the presence of a magnetic field.

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Information Card and Reader

Information card 10 carries a specularly reflective magnetizable stripe 11 that is covered by a thin dielectric film 12. Information can be recorded on and read from stripe 11 magnetically, using conventional magnetic techniques. In addition, information can be optically recorded on stripe 11 by forming small regions with different reflectivity, such as holes. Furthermore, high density magnetic information can be recorded using the Curie Point writing technique. That is, a small region of the stripe is heated to the Curie Point and allowed to cool in the presence of a magnetic field. All of the information thus recorded on the stripe can be read by a single sensing apparatus comprising a light source 13 that delivers a beam of polarized light 14 which passes through a beam splitter 15, a 45OE polarization rotator 16 and a converging lens 17. The beam reflects off the stripe 11 and presents a returning beam through lens 17, rotator 16 and beam splitter 15. Beam splitter 15 will divert light, that has been rotated 90OE, to sensor
18. Magnetic data 19 on stripe 11, interacting with the reflected light beam 14, causes a further magneto-optic Kerr rotation of the polarization angle, thereby reducing the total amount of light directed to the sensor 18 by beam splitter 15. Thin dielectric film 12 allows multiple reflections and enhances the Kerr rotation. Film 12 also protects the stripe. Sensor 18 thus can detect the presence of magnetized r...