Magneto-optical recording and readout device

Claim 1

AN OUT-OF-CONTACT SYSTEM FOR RECORDING AND REPRODUCING HIGH DENSITY DIGITAL DATA COMPRISING IN COMBINATION: A MOVABLE RECORD MEMBER COMPOSED OF A NONMAGNETIC SUBSTRATE HAVING A THIN FILM RECORD SURFACE OF FERROMAGNETIC MATERIAL COATED THEREON, THE THICKNESS OF SAID FILM BEING CHOSEN SUFFICIENTLY THIN IN CONJUNCTION WITH THE FERROMAGNETIC MATERIAL OF WHICH IT IS COMPRISED SO AAS TO PROVIDE A SUBSTANTIALLY RECTANGULAR HYSTERESIS CHARACTERISTIC FOR MAGNETICALLY STORING A SERIES OF HIGH DENSITY HIGH AND LOW LEVEL BINARY SIGNAL CURRENTS OF DIGITAL DATA, A MAGNETIC RECORD HEAD DISPOSED IN CLOSE PROXIMITY TO SAID THIN FILM RECORD SURFACE, SAID RECORD HEAD BEING RESPONSIVE TO SAID BINARY SIGNAL CURRENTS FOR MAGNETICALLY RECORDING SAID DIGITAL DATA AS THE RECORD SURFACE PASSES UNDER SAID RECORD HEAD TO PRODUCE A HIGH DENSITY MAGNETIC RECORDING OF DIGITAL DATA IN SAID RECORD SURFACE; AND OPTICAL REPRODUCING MEANS FOR REPRODUCING DIGITAL DATA MAGNETICALLY RECORDED IN SAID THIN FILM RECORD SURFACE BY SAID MAGNETIC RECORD HEAD COMPRISING, MEANS FOR PRODUCING A POLARIZED BEAM OF LIGHT AND FOCUSING SAID BEAM OF LIGHT ONTO PREDETERMINED PORTIONS OF SAID RECORD SURFACE SO THAT THE POLARIZATION OF THE BEAM OF LIGHT IS RESPONSIVE TO THE DIGITAL DATA RECORDED IN SAID RECORD SURFACE, AND MEANS INCLUDING ANALYZER MEANS FOR DETECTING CHANGES IN THE POLARIZATION OF SAID LIGHT BEAM TO REPRODUCE SAID HIGH AND LOW LEVEL BINARY SIGNAL CURRENTS OF DIGITAL DATA.