| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical pickup in which the adverse effect caused by dust and litter to a hologram is surely prevented. SOLUTION: The pickup has a semiconductor laser 2, photodetectors 5A, 5B and 5C and hologram elements 11, 12, 13 and 14 which are arranged in the optical path between a recording medium 3 and the photodetectors 5A, 5B and 5C. The returning light beams from the medium 3 are passed through the elements 11, 12, 13 and 14 and received by the photodetectors 5A, 5B and 5C of the photopickup. Among the elements 11, 12, 13 and 14, the back stage second hologram elements 13 and 14, which further diffract the diffracted light beams by the front stage first hologram element 12, are hermetically sealed by hermetically sealing members 34, 7 and 32. |
