OPTICAL REPRODUCING DEVICE

摘要

PURPOSE:To use an optical reproducing device for reproduction from both single-track reproducing disk and double-inclined surface simultaneously reproducing disk on the market, by dividing a photodetector into two photodetecting sections for receiving the reflected beams of + or -1st-order diffracted lights and into four sections for receiving the reflected beams of 0-order diffracted lights. CONSTITUTION:An incident (a) emitted from a semiconductor laser 21 is divided into three parts of 0-order diffracted lights and + or -1st-order diffracted lights at a diffraction grating 22 and converged onto a disk 26. Reflected lights (b) from the disk 26 are separated from the incident optical path by means of a polarization beam splitter 23 and received by a photodetector 28 after passing through a cylindrical lens 27. The shape of the photodetector 28 is divided into two parts for receiving reflected beams 41 and 42 of the + or -1st-order diffracted lights and into four parts for receiving reflected beams 43 of the 0-order diffracted lights. By combining photoreceiving signals at these eight photodetecting sections, this optical reproducing device can be used for reproduction from both- track reproducing disk and double-inclined surface simultaneously reproducing disk on the market.