Patent ID: 7391695
Filing Date: 2008-06-24
Classification: G11B

Abstract:
1. An information recording method for recording information based on a mark-length recording system where laser light irradiates an information recording medium, an information-recorded portion being physically different from an information-unrecorded portion formed in a recording area on the information recording medium, and the information-recorded portion and one of the information-unrecorded portion or an erased portion are changed in length, and that performs recording, reproducing, and erasing of information on the information recording medium, the method comprising: a step of using a recording waveform for forming a record mark, which recording waveform is substantially composed of three pulses: a first pulse, an intermediate pulse, and a last pulse; and a step of controlling the recording waveform to satisfy: a relationship in which the length of the first pulse is less than two times as long as the length of a first cooling pulse; a sum of the length of the intermediate pulse and the length of an intermediate cooling pulse is 1T; and the intermediate pulse and the intermediate cooling pulse are sequentially added to an intermediate portion of the recording waveform of a recording code 6T, when the length of the recording code is more than 6T, where T is a reference clock period; wherein the recording is performed by using laser light having a wavelength of about 0.4 μm and produced by an apparatus having an NA of about 0.85, and wherein when the length of the recording code is greater than 6T, the ratio of a intermediate pulse length to a first cooling pulse length is less than 1.0 and the ratio of the intermediate pulse length to an intermediate cooling pulse length is less than 1.0.