| 摘要 |
PURPOSE:To obtain an inexpensive reproducing device of simple structure by irradiating a photomagnetic material of vertical magnetism with circular polarized light parallel to a magnetization direction, and reading information on the basis of its quantity of reflected light or transmitted light. CONSTITUTION:A laser light beam which is polarized by a polarizer into P polarized light passes through a polarization beam splitter 14 and is made into circular polarized light by a quarter-wavelength plate 16. When clockwise circular polarized light is incident on a photomagnetic disk 18, it is reflected by the photomagnetic material 22 and an aluminum reflecting film 26, but reflected light returning to the wavelength plate 16 is clockwise when viewed from the wavelength plate 16 and reflected light incident on the wavelength plate 16 is converted into S polarized light, which is made incident on a splitter 14. The splitter 14 reflects the S polarized light, which enters a photodiode 20. The quantity of incident light thereof varies according to the difference in the vertical magnetization direction of the photomagnetic material 22, so written information is detected from the photodiode 20. |
