| 摘要 |
PURPOSE:To check instantaneously recording information, to increase the depth of focus and to adjust the assembling of a head easily by arranging an optical system for radiating light for recording and erasing information so as to be separated from an optical system for radiating reproducing light. CONSTITUTION:An optical system is divided into one optical system 50 for shaping the light obtained from the 1st light source 20 radiating information recording or recording/erasing light as an elliptical laser spot 101 and the other optical system 60 for shaping the light obtained from the 2nd light source 30 radiating information reproducing light as an approximately circular laser spot 102 and an optical system 70 for guiding the reflected light for reproduction is also arranged. Since recording and reproduction can be executed by laser spots 101, 102 respectively, instantaneous checking of reproduction can be attained. Since the beam diameter of the laser spot 101 is large, the focal depth is increased and the assembling of the head can be easily adjusted. |
