| 摘要 |
PURPOSE:To obtain an optical head capable of performing the adjustment of a beam pitch with the accuracy of about 5 microns. CONSTITUTION:The recording and reproducing of information toward an optical disk 10 are performed by irradiating the optical disk 10 with a laser beam emitted from a semiconductor laser 1 via an objective lens 9 and passing the reflected light beam through a composite detecting prism 11 and guiding it to first and second photodetectors 16, 17. The composite detecting prism 11 passes one part of the laser beam entering from a transmissive plane and has a half mirror 13 capable of reflecting one part of an incident laser beam to the right angle direction with respect to the optical axis and a mirror plane 15 for guiding the reflected light beam to a direction parallel with the optical axis and a second polygonal pillar 22 is joined to the prism 11 on a second transmissive plane 14 arranged in parallel with the optical axis. |
