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Magneto Optic Transducer System

IP.com Disclosure Number: IPCOM000090195D
Original Publication Date: 1969-Mar-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Wellbrock, AG: AUTHOR

Abstract

This system is for reading magnetically recorded datum magneto-optically. Data is recorded on a relatively high coercive force magnetic record media 2. The latter is then brought into magneto-coupled relation with a magneto-optic transducer 3 composed of transparent substrate 4 and ferromagnetic film 5 of relatively low coercive force. This results in the magnetic transfer of the data to film 5. Readout is accomplished by directing a polarized beam of light at transducer 3, by which the polarized light is caused to rotate, depending on the magnetic state of the film upon which it impinges. The light reflected from transducer 3 passes through a polarizing analyzer and then to a detector. The analyzer prevents the rotated portions of the beam from reaching the detector.

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Magneto Optic Transducer System

This system is for reading magnetically recorded datum magneto-optically. Data is recorded on a relatively high coercive force magnetic record media 2. The latter is then brought into magneto-coupled relation with a magneto-optic transducer 3 composed of transparent substrate 4 and ferromagnetic film 5 of relatively low coercive force. This results in the magnetic transfer of the data to film 5. Readout is accomplished by directing a polarized beam of light at transducer 3, by which the polarized light is caused to rotate, depending on the magnetic state of the film upon which it impinges. The light reflected from transducer 3 passes through a polarizing analyzer and then to a detector. The analyzer prevents the rotated portions of the beam from reaching the detector. Thus, the pattern of light detected is indicative of the magnetic data transferred from media 2 to transducer 3.

Substrate 4 is in the form of a nonplanar body such as a prism. Such a configuration is desirable as it can be arranged to allow light to enter it from the normal, thus avoiding diffraction of the beam at the air-substrate interface. It also manifests total internal reflection at the ferromagnetic film-air interface so that the greatest amount of light signal is reflected from transducer 3 to the detector. The benefits of this nonplanar substrate 4 configuration are enhanced by placing notches 6 in its face of the substrate. Each notch face 7 is parallel to...