Optical recording and reproducing device

Abstract

Abstract PURPOSE:To stabilize the operation of the tracking sero system, by providing the light shielding plate with a hole for the purpose of reducing the diameter of the light flux from the light source at a reproducing time. CONSTITUTION:Light shielding plate 8 with hole 7 formed is provided removably between light source 1 and half mirror 2. At the recording time, light shielding plate 8 is not interposed in the light path; and at the reproducing time, light shelding plate 8 is interposed to reduce the diameter of the light flux, and therefore, the diameter of the light flux to condenser lens 4 becomes small. Consequently, even if movable mirror 3 is rotated finely, a part of the reflection light due to movable mirror 3 is prevented from being not incident to condenser lens, and the light quantity and light quantity balance to photodetector 6 become constant independently of rotation of movable mirror 3, and thus, the stable servo operation is performed.

Inventors

• 👤 Toru Nakamura

Bibliographic Details