| 摘要 |
PURPOSE:To make the constitution of a device small in size and light in weight and to efficiently detect a signal by making a laser light beam incident through an optical system such as a semiconductor laser, a microprism and a galvanomirror on a common substrate and receiving a reflected light beam from an optical disk by a photodetector without passing through the optical system. CONSTITUTION:The laser light beam by the optical system such as the semiconductor laser 2, the microprism 3 having a reflection film 4 on its surface and the galvanomirror 6, which are provided on the substrate 1, is made incident on an objective lens 8 equipped with a hologram 9 and radiates the optical disk 10. The reflected light beam from the disk 10 is received and detected by quadripartite photodetectors 7a and 7b on the substrate 1 through a hologram 8 without passing through the mirror 6, etc. Thus, an optical pickup device, which has a short return optical path to make the loss of a light quantity small and which can detect the signal with high efficiency because of the small-sized and light constitution where a two-dimensional actuator is not needed as an objective lens actuator, is obtained. |
