Patent ID: 7808880
Filing Date: 2010-10-05
Classification: B82Y,G11B

Abstract:
1. An optical disk drive, comprising: a movable sled; an optical pick up unit (OPU) connected to the sled, the OPU including a laser configured to transmit a laser beam; a hybrid solid immersion objective lens configured to evanescently couple the laser beam onto the optical disk; and an actuator for moving the hybrid solid immersion objective lens (SIOL) to change a position of the evanescently coupled laser beam on the optical disk, wherein the laser has a coherence function that depends upon a roundtrip optical path length of the laser beam, the coherence function having coherence value maxima spaced apart by intervals, and wherein the disk drive is configured so that the roundtrip optical path length of the laser beam is within one of the intervals.