Patent ID: 7742371

Claim:
An information recording and reproduction apparatus which records and reproduces information by irradiating a laser light onto a recording medium, comprising: a light source which emits the laser light; a driving signal generating unit which generates a laser driving signal having a write power level corresponding to performing recording an information onto the recording medium, an erase power level corresponding to performing erasing a recording mark recorded onto the recording medium, or, a read power level corresponding to neither recording nor erasing on the recording medium; a high frequency superimposing unit which superimposes a high frequency signal on the laser driving signal; and a control unit which drives the light source by the laser driving signal on which the high frequency signal is superimposed to perform recording and reproduction, wherein a level of the high frequency signal at a time of recording is different from the level of the high frequency signal at a time of reproduction, wherein the control unit detects a recording information based on an inputted information, wherein the high frequency superimposing unit changes the level of the high frequency signal at the timing of a first predefined time period after detecting the recording information, wherein the control unit transits from a reproduction state to a recording state by changing the power level from the read power level to the erase power level at the timing of a second predefined time period after detecting the recording information, and records the recording information onto the recording medium by changing the power level from the erase power level to the write power level, wherein the second predefined time period is longer than the first predefined time period, wherein difference between the second predefined time period and the first predefined time period is equal to or longer than a transient response period of a waveform of the laser light, and wherein the level of the high frequency signal at the time of the recording is equal to or smaller than 4 mWpp when the recording medium is a DVD±RW.