Patent ID: 6577565
Filing Date: 2003-06-10
Classification: G11B

Abstract:
A device for reading information from a recording medium having a plurality of prepits, the device comprising:a light emitting device for emitting a light beam to the recording medium; a first dividing device for dividing the light beam reflected by the recording medium into a first divided beam and a second divided beam; an astigmatism producing device for producing astigmatism in the first divided beam; a first light receiving device for receiving the first divided beam from the astigmatism producing device; a second light receiving device for receiving the second divided beam from the first dividing device; a first detecting device for carrying out a focus error detection on the basis of the first divided beam received by the first light receiving device; and a second detecting device for detecting the plurality of prepits on the basis of the second divided beam received by the second light receiving device.