Patent ID: 7675835
Filing Date: 2010-03-09
Classification: G11B

Abstract:
1. An optical disk drive, comprising: a movable sled operable to translate in a parallel direction with respect to an optical disk surface; an optical pick up unit (OPU) connected to the sled, the OPU configured to transmit a laser beam parallel to an optical disk surface; a means for redirecting the transmitted laser beam normally to the optical disk surface and for redirecting a resulting reflected laser beam from the optical disk into the parallel direction towards the OPU, the means being separate from the OPU; an objective lens configured to focus the redirected beam onto the optical disk; and an actuator for moving the objective lens to change a position of the focused beam, wherein a laser in the OPU has a coherence function having maxima spaced apart by intervals, and wherein the disk drive is configured such that a roundtrip optical path length of the laser beam is located in one of the intervals, and wherein the roundtrip optical path is less than 25 millimeters.