| 摘要 |
PURPOSE:To surely erase recording by a change of the crystal state of a recording layer or a phase change thereof by irradiating a recording medium with light so as to have the spot longer than the length in the track width of the spot of the light beam used at the time of recording on the recording medium surface. CONSTITUTION:The recording formed by subjecting the recording medium consisting of an optothermal conversion layer which absorbs light and converts the light to heat and an org. compd. crystal film which executes recording and erasing by reversibly generating the crystal state change by heat to photoirradiation of a short period of time is erased by irradiat ing this recording medium with the light so as to have the spot longer than the length in the track width of the spot of the light beam used at the time of recording on the recording medium surface. The recording medium formed by using chromium for the optothermal conver sion layer and a fatty acid for the recording layer is used and the erasing of the recording formed on this medium is preferably executed by confining the photoirradiation time at the time of recording to <=1mum sec. The entire part of the recording part is put into an erasing temp. range and the perfect erasing without imperfect erasing is executed by specifying the length of the beam in the track width direction to the length larger than the length at the time of recording if the irradiation time of the erasing light is 50mu sec when the record ing is executed by irradiation with 1mumphi beam for 0.25mu sec. |
