Patent TW-200402048-A (TW)
Title: Optical recording medium
Inventor: KOBAYASHI TATSUHIRO
IPC: G11B7/1267
Filed: 2003-06-27
Abstract: The invention targets at providing the laser beam power determining method, in spite of cross erase effect, that the jitter of regenerated signal acquired by putting regenerated records in rewritable optical recording medium is limited within an allowable range and the level become highest in determining recording power of laser beam. The laser beam power determining method comprises varying the recording power of laser beam and recording first test signal of the rewritable optical recording medium; before measuring each recording power of laser beam is affected by cross erase, regenerating the amplitude A0 of regenerated signal acquired from the first test signal and after it is affected by first cross erase, regenerating the amplitude A1 and jitter J1 of regenerated signal acquired from the first test signal; after effect of cross erase is saturated, regenerating the amplitude As and jitter Js and regenerated signal acquired from the first test signal; meanwhile, before it is affected by cross erase, regenerating the amplitude A0 of regenerated signal acquired from the first test signal and after first cross erase effect, regenerating the function of difference between amplitude A1 of regenerated signal acquired from the said first test signal to calculate first parameter from each recording power of the laser beam; after it is affected by first cross erase, regenerating the amplitude A1 of regenerated signal acquired from the first test signal and after cross erase effect is saturated, regenerating the function of difference for the amplitude As of regenerated signal acquired by the first test signal to calculate the second parameter based on each recording power of the laser beam; after the cross erase effect is saturated, regenerating the jitter Js of regenerated signal acquired from the first test signal and after first cross erase effect, regenerating the function of difference of jitter J1 of regenerated signal acquired from the first test signal to calculate the third parameter based on each recording power of the laser beam. The critical parameter is decided by corresponding the second parameter value to the first parameter value when the calculated third parameter equals to an allowable value and the recording power of the laser beam is varied to record the second test signal of the rewritable optical recording medium; signal characteristics of the regenerated signal acquired by the second test signal when regenerating record to the rewritable optical recording medium comply with standard conditions. The amplitude AA0 of regenerated signal acquired by regenerating the second test signal before measurement is affected by cross erase is measured for each recording power of the laser beam, the amplitude AA1 of regenerated signal acquired by regenerating the second test signal after the first cross erase effect and the function of difference for amplitude AA0 of regenerated signal acquired by regenerating the second test signal before cross erase effect in accordance with the amplitude AA0 of regenerated signal and the amplitude AA1 of the regenerated signal acquired by regenerating the second test signal; after the first cross erase effect, the function of difference of the amplitude AA1 is acquired from regenerating the said second test signal to calculate the fourth parameter.When the said fourth parameter is below the critical parameter,the recording power,when acquiring the fourth parameter of the laser beam, is used as the best recording power.