| 摘要 |
PURPOSE:To obtain an optical head provided with a recording power equal to a normal optical head and a reproduced beam spot having a converged spot diameter smaller than that of a conventional super-high resolution optical head. CONSTITUTION:A converged beam spot is formed on the disk surface of an optical disk 9 with an objective lens 8 by superimposing luminous fluxes from light sources having different wave lengths by a wave length superimposing beam splitter. A luminous flux from a reproduced semiconductor laser having a short wave length passes light shielding bands to form a super-high resolution beam spot being suitable for a reproduction, a luminous flux from a recording semiconductor laser having a relatively long wave length focuses a normal beam spot on the optical disk 9. Luminous fluxes having respective wave lengths reflected at the optical disk 9 are reflected at a signal detecting beam splitter to be received by bisected detectors 16, 18. A reproducing luminous flux is made to be the super-high resolution spot by a re-converging lens to be re- focused on a slit 13 and only a main robe is cut out and then only information in a desired recording pit are read out. |
