| 摘要 |
PROBLEM TO BE SOLVED: To provide such an optical head, for an optical recording and reproduting device, that corrects the astigmatic difference of light emitted from a light source, and that provides a satisfactory reproducing performance for a miniaturized integrated structure. SOLUTION: A laser diode 4 and a signal photodetecting element 5 are provided integrally inside the same optical unit 1, with a cylindrical lens 10 provided on the lower face of an optical branching element 6, or with the element 6 inclined or constituted of a resin so that the orientational direction of the resin crystal is arranged in the direction of correcting astigmatic difference; furthermore, using a method in which the optical branching element 6 is made an astigmatic hologram element generating astigmatism, the optical branching element 6 is integrated with the means for correcting the astigmatic difference, thereby realizing an optical head that is small and also capable of a good reproducing performance in an optical recording and reproducing device. |
