| 摘要 |
PURPOSE:To use optical parts in common and to contrive miniaturization and light weight of a device by passing the light guided from a light source to a storing medium and the light guided from the information storing medium to a photodetector through similar optical paths. CONSTITUTION:A semiconductor laser 21 and the photodetector 29 are disposed on the same mount 30. A collimator lens 22 in common use as a projection lens is used as a lens for making the laser light L of a light transmission system emitted from the laser source 21 parallel and also used as a lens for converging the laser light L of a photodetecting system. Since the light L of the light transmission system guided to the information storing medium 7 from the laser source 21 and the light L of the photodetecting system guided to the photodetector 29 from the medium 27 can pass through the similar optical path, like the lens 22, the optical parts are made common and the number of the optical parts can be reduced. Accordingly, the compact and lightweight device is realized and the access time can be shortened. |
