Optical information recording and reproducing apparatus

Claim 1

An optical information recording and reproducing apparatus which comprises a light emitting means (1), a focusing means (6) for collecting light emitted from said light emitting means (1) onto a magneto-optical recording medium (7) for raising temperature at the recording portion of said magneto-optical recording medium (7) above Curie temperature so as to magnetize the recording portion in a direction of external magnetic field, thereby to effect recording of information, an analyzing means (9) for sepa­rating the light reflected from the magneto-optical record­ing medium (7) into polarization components in two direc­tions corresponding to magnetizing direction in the magne­to-optical recording medium (7), corresponding photo-detect­ing means (10, 11) for converting the separated light components into electrical signals so as to obtain reproduc­tion signal from the information signal thus obtained, said optical information recording and reproducing apparatus further comprising a subtracting means (12) for subtracting the information signal obtained by the respective photo-de­tecting means (10, 11) during recording function, a waveform shaping means (15) for adjusting the waveform of output signal from said subtracting means (12), and a comparing means (16) for comparing the output signal of said waveform shaping means (15) with a preliminarily set threshold value.