| 摘要 |
PURPOSE:To simplify and make light weight the constitution of an optical head for an optical recording medium, to improve the speed of an access time and to improve mass-productivity. CONSTITUTION:A composite beam splitter 5 is arranged between a semiconductor laser 1 and a collimating lens 2. This composite splitter 5 is provided with two reflection faces 6, 7. Reflected light beams from a magnetic disk 4 are reflected from the reflection faces 6, 7 respectively and are received to photodetectors 11, 12. On the front sides of the photodetectors 11, 12, photodetecting elements where polarization directions are orthogonally crossed each other are arranged. The photodetectors 11, 12 consist of tripartite photodiodes respectively. A beam size method for the detection of a focusing error and a push-pull method for the detection of a tracking error are used respectively. These method are applicable for the data reading of the optical disk, as well. |
