| 摘要 |
PROBLEM TO BE SOLVED: To secure compatibility for plural kinds of optical recording media with different later constitution, to miniaturize a device itself and to realize reproduction of an information signal with high reliability by sharing a part with plural optical paths. SOLUTION: Light source 3a, 4a emit laser light with different wavelengths answering to plural kinds of optical disks with different layer constitution. Objective lenses 5a, 5b converge the laser light outgoing from the light source 3a, 4a on a recording layer of a preserved optical disk. An objective lens switch mechanism 20 switches the objective lens 5 to a recording/reproducing position and move it. A spectroscopic means light divides the incident light outgoing from the prescribed light sources 3a, 4a and the reflection laser light reflected by the optical disk. The photodetectors 4b, 6 receives the reflection laser light light divided by the spectroscopic means. Then, an optical system correction means corrects the prescribed objective lens 5. |
