| 摘要 |
PURPOSE:To eliminate the need for tilting an optical system in a skew correction system and also to attain a compact and lightweight structure of the optical system, by focusing the luminous flux having the wave front aberration of the reversed characteristic to that produced by the skews of a disk. CONSTITUTION:When a disk 11 has a skew, the skew angle DELTAtheta is detected by a skew detector. Then the rocking part of a wave front aberration generation means 20 at a fixed part 17 is rocked in response to the angle DELTAtheta, and a parallel plate 5 is tilted at an angle -DELTAtheta. Therefore the luminous flux condensed to the plate 5 by a condenser lens 4 produces a wave front aberration when it passes through the plate 5. This aberration has the reversed characteristic to the wave front aberration produced by a transparent layer 11a of the disk 11. Thus the layer 11a produces no wave front aberration by condensing the luminous flux having said reversed characteristic to a recording surface 11b of the disk 11. Then the luminous flux is condensed to the surface 11b with no skew at all. |
