Patent ID: 7269120
Filing Date: 2007-09-11
Classification: G11B

Abstract:
1. An optical pickup comprising: a base made of synthetic resin, the base having a light passage hole penetrating the base, a laser hole communicating with the light passage hole, and a laser mounting surface formed at a periphery of an opening of the laser hole and having threaded holes; a half mirror disposed in the light passage hole; a photodiode disposed on one end opening of the light passage hole; a collimator lens disposed on another end opening of the light passage hole; an objective lens provided at the another end opening of the light passage hole; a laser diode disposed in the laser hole; a metallic holder retained on the laser mounting surface, the holder having a retaining hole provided penetratingly in the holder concentrically with the laser hole and through holes; and a metallic radiating plate attached to an outer surface of the holder, the radiating plate having an engaging hole provided penetratingly in a substantially central portion of the radiating plate and a diameter of which is slightly smaller than that of the retaining hole; wherein laser light is projected from the laser diode onto a disk through the half mirror, the collimator lens, and the objective lens, and reflected light thereof is received by the photodiode through the half mirror, so as to read information recorded on the disk; the laser diode is fitted in the retaining hole of the holder; the engaging hole of the radiating plate is positioned concentrically with the laser diode, thereby clamping the laser diode by the radiating plate and the holder; slits are formed in the radiating plate to form a pair of tongues in the manner of point symmetry about an axis of the engaging hole; screw inserting portions formed in the respective tongues are made to communicate with the slits; screws are passed through the screw inserting portions of the tongues and the through holes of the holder, and are screwed into the threaded holes of the laser mounting surface, thereby securing the radiating plate and the holder to the base; the axis of the engaging hole is positioned on a phantom line connecting points of application of force generated at proximal end portions of the tongues when the screws are screwed in, and distances from the axis to the respective points of application of force are set to be substantially identical; a recessed portion is formed on a portion of the laser mounting surface excluding peripheral edge portions of the threaded holes, thereby defining a gap between the holder and the base; and a plurality of radiating fins are projectingly provided on the holder.