| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical head device wherein light condensed into a recording layer through an objective lens is not affected by the thickness nonuniformity of a transparent resin layer located between the recording layer and the objective lens, an information recording and reproducing device and information recording and reproducing method using the optical head device, and a thickness nonuniformity detecting method. <P>SOLUTION: This optical disk device 1 has a focal point out-of-focus detection system 102 for detecting a focal point out-of-focus of the objective lens 4, a thickness nonuniformity detection system 103 for detecting the thickness nonuniformity of the transparent resin layer 3a provided the closest to an objective lens of a recording medium 2, and a thickness nonuniformity correction mechanism 101 for changing an image formation characteristic of light made incident on the objective lens on the basis of a thickness change in the transparent resin layer detected by the thickness nonconformity system. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
