| 摘要 |
PURPOSE:To obtain a safe information reproducing signal, by providing a reflecting element to feed back a part of light irradiated from a laser to the laser, between the laser and an optical path separating element. CONSTITUTION:The light irradiated from the semiconductor laser 1 is made into a parallel luminous flux by a lens 2 and imaged on a disc 4 by a lens 3 through a semitransparent mirror 8, a part of the light is reflected by the mirror 8 to be laser feedback light 9 and a prescribed luminous amount is fed back to the laser 1 at all times. The reflected light of the disc 4 is all directed to a detection system 7 by a lambda/4 plate 10 and a polarized prism 11. Thus, the prescribed amount of laser feedback light independently of errors in automatic focus control and the information on the disc is attained. |
