| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical head device and an optical information recording/reproducing device capable of detecting the position of land/groove for a disk having an optional track pitch and capable of easily adjusting the position of an optical device. SOLUTION: The devices are provided with a light source part 202 exiting a main beam and a sub beam, an objective lens 6 condensing each beam on a disk D1, and a photodetector 11 receiving reflected light from the disk D1. The light source part 202 is provided with a diffraction optical device 3 which shifts a distance from the objective lens 6 to a condensing point of the main beam and the sub beam with respect to at least the radial direction of the disk D1, the photodetector 11 is provided with light receiving parts 21-40 for each of the main beam and the sub beam and also the light receiving parts 29-40 for the sub beam respectively and individually receive light at the central part and both end parts in the radial direction of the sub beam. |
