| 摘要 |
PROBLEM TO BE SOLVED: To reduce the influence of a noise at the time of recording a signal, by providing a module circuit performing a high frequency modulation to a light source while superposing a high frequency on the driving current of the light source. SOLUTION: The module circuit 4 is connected to between a driving circuit 43 supplying a driving current to a semiconductor laser element 21 and the element 21 and performs a high frequency modulation while superposing a high frequency on the driving current and selectively supplies a driving voltage V1 or V2. Then, asstigmatism of light beams from the element 21 is compensated by an astigmatism compensating plate 22a and the beams are converted into parallel light beams by a collimating lens 24 and the light beams are reflected with a prism mirror 25 to be converged on the signal recording surface of an optical disk with an objective lens 26. Return light beams from the optical disk are reflected by the polarized light separating film of a beam splitter 23 to be converged on a photodetector 29. The recorded signal of the optical disk is reproduced based on the detection signal of the detector. |
