| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical head capable of realizing a recording/reproducing operation of three kinds of optical disks having the different thicknesses by using one objective lens and to provide an apparatus applying them. <P>SOLUTION: The apparatus is equipped with: 1st, 2nd volume holograms for diffracting a red light; 3rd, 4th volume holograms for diffracting an infrared light; and a refractive lens, and a blue light is converged to a transparent layer of 0.1mm by the refractive lens through the volume hologram, and for the red light, the diffracted lights of the 1st volume hologram are partially crossed and incident to the 2nd hologram, and the diffracted lights of the 2nd volume hologram are converged to a transparent layer of 0.6mm by the refractive lens. The infrared light, is diffracted as well as the red light by the 3rd, 4th volume holograms to be converged to a transparent layer of 1.2mm by the refractive lens. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
