| 摘要 |
<P>PROBLEM TO BE SOLVED: To easily and surely compensate each of a spherical aberration and a coma aberration generated for every optical recording medium, and to compensate these two aberrations by one compensation element. <P>SOLUTION: An aberration compensating optical system 104 is constituted of two groups and consists of a lens 104a of positive refractive power to the side of a semiconductor laser 101 and a lens 104b of negative refractive power to the side of the optical recording medium 110. For a 1st blue ray optical recording medium 110a, an amount of the spherical aberration generated by a thickness difference of a substrate is detected, and for a 2nd blue ray optical recording medium 110b, an amount of the coma aberration generated by a tilt is detected, then each lens is dynamically controlled to obtain optimum characteristics. These lenses 104a and 104b are held on actuators 121, 122 of a driving means and controlled by a CPU 125, and a space between the lenses are made variable by uniaxially driving the lens 104a to the direction of optical axis, and the lens 104b is made movable to the radial direction of optical recording medium in the vertical direction of optical axis. Thus, the generated spherical aberration and coma aberration are compensated by one compensation element, so as to perform the recording, reproducing or erasing operation with respect to the optical recording medium. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
