| 摘要 |
PURPOSE:To stabilize the intensity of a beam reflected by a reflection mirror by making the reflective layer of the reflection mirror of a metallic film. CONSTITUTION:The beam from a light emitting source 8 disposed on the outside of a rotary drum 1 is reflected on a mirror 3 disposed in the rotary drum 1 so as to be guided to an optical tape 7 which is wound around the outer peripheral part of the rotary drum 1. And then, the reflective layer of the mirror 3 is made a metallic reflective layer. There is a little change in the reflectance of the metallic reflective film compared with the change in the deflecting direction of the beam made incident on the reflection surface, so that the intensity of the beam reflected by the reflection mirror 3 does not change even if there is a change in the relation between the beam deflecting direction and the reflective surface of the reflection mirror 3 when the reflection mirror 3 is rotated with the rotation of the rotary drum 1 at the time of recording and reproducing. Thus, the reflectance of the reflection mirror corresponding to the rotation of the reflection mirror and the intensity of the beam can be stabilized. |
