| 摘要 |
<P>PROBLEM TO BE SOLVED: To avoid a light quantity variation on an optical disk caused by the interference of a light beam emitted from a laser light source and a reflected light beam reflected by the optical disk and returned to the laser light source. <P>SOLUTION: This pickup is provided with a laser light source 1, a collimator lens 49 making outgoing light from the laser light source to almost parallel light, an objective lens 7 converging the light beam on an optical disk 9, an actuator 8 driving the objective lens to a focusing direction and a tracking direction, a photodetector 11 receiving the reflected light from the optical disk of the light beam, and a refractive index varying plate 5 which is arranged between the collimator lens and the objective lens and can vary the refractive index. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
