| 摘要 |
PROBLEM TO BE SOLVED: To contrive reduction in the cost of an optical pickup using two beam splitters. SOLUTION: The two beam splitters are both composed of parallel plates 11, 19, with a further cost reduction contrived compared with a conventional structure using a prism. In addition, the parallel plate 11 is made thinner in the thickness, harder in the material, and smaller in the inclination, in comparison with the parallel plate 19, so that generation of astigmatism or coma- aberration is reduced in the optical path to an optical disk 2. |
