| 摘要 |
PURPOSE:To make it possible to record many kind of information and to detect the depth of recording bit, by dividing the emitted beam into two polarized waves which cross orthogonally each other and giving a slight angle displacement, and by receiving its reflecting light. CONSTITUTION:Polarizing element 3 such as Wollaston prism is placed in the midway of optical part, and the emitted light from a semiconductor laser is separated into two polarized luminous fluxes which cross orthogonally each other, and a slight displacement is given to that angle. These two fluxes of light which has the angle displacement are projected on a medium 5 through a lens 4, and their reflecting light is detected by a photodetector 7. The strength of the interference light of the photodetector 7. varies only by the difference of the position of the two luminous fluxes on the medium, and the difference of the depth is measured by the difference of the phase. Therefore, it is possible to record many kinds of information according to the depth, and information density will be improved. |
