| 摘要 |
PROBLEM TO BE SOLVED: To provide an information recording and reproducing device for irradiating an information recording medium with an optical beam having required optical power corresponding to the number of recording layers in recording/ reproducing information on/from the information recording medium having a plurality of recording layers. SOLUTION: This information recording and reproducing device 1000 is provided with a light source 1 for emitting a first optical beam having prescribed optical power Ppre , a discriminating means 20 for discriminating the number of recording layers belonging to the information recording medium 9, an optical beam transmission adjusting means 1002 for adjusting the transmission quantity of the first optical beam, and a converging means 1003 for converging the first optical beam on the information recording medium. When an information recording means 9 is composed of one layer, the optical beam transmission adjusting means 1002 adjusts the prescribed optical power Ppre to be first optical power P1 , when the information recording means 9 is composed of two layers, the optical beam transmission adjusting means 1002 adjusts the prescribed optical power Ppre to be second optical power P2 , and the first and the second optical power P1 and P2 satisfy a relation P1 <P2 <=Ppre . |
