| 摘要 |
PURPOSE:To realize an optical head with simple construction and light weight of the moving part, by dividing reflected light from a recording medium into two (left and right) at the inside of an optical head, using one for an out-of-focus signal detection and a track shift signal detection, leading out the other to the outside of the said optical head for attaining the reproduction of information. CONSTITUTION:The reflected light subject to the rotation change of the polarized plane in response to the information of a recording medium 25 passes through an objective lens 24 and a full reflection mirror and is separated at a half mirror 22 and divided into left and right and a full reflection mirror 26. One light is converted into an electric energy at a photodetetor 28 via a lens 27. The photodetector 28 is split into four, each output forms a track shift signal and an out-of-focus signal. Further, the other light divided into two at the full reflection mirror 26 is transmitted from an optical head A while it remains as a parallel light into the outside, and received at a signal reproducing section B fixed on the optical path and reproduced into an inormation signal with an analyzer 28, a lens 30 and a photodetector 11. |
