Optical information recording and erasing method using two laser beams on a phase change optical recording medium

摘要

A method for performing a high quality recording of information signals on an optical disk utilizes reversible structural changes between crystalline and amorphous states of a chalcogenide glass film or the like and two circular or nearly circular laser spots closely arranged along a recording track of optical disk. The preceding spot, which emits a continuous mode or high-frequency mode by far exceeding the recording frequency, operates cancel the past history in the irradiated portion by melting the recording film. The succeeding spot, which is modulated between the power levels for amorphizing and crystallizing according to the recorded information, operates to record new information signals on the track just after erased by the preceding laser spot.