OPTICAL RECORDING MEDIUM

摘要

The optical recording medium of the present invention is a phase change optical recording medium which can be used as a write once medium and which can be recorded at a high recording density. The optical recording medium of the present invention is adapted for recording such that, when the recording beam has a wavelength of lambda , and objective lens of recording optical system has a numerical aperture of NA, minimum record marks formed are circular or ellipsoidal marks having a length of 0.4 lambda /NA or less; and the medium is a write once medium wherein the recorded information can not be erased or rewritten at the minimum linear velocity used. <IMAGE>