| 摘要 |
PURPOSE:To improve the reproducing efficiency of a reproducing light and the C/N ratio in an optical head which deflects the path of the reproducing light by using hologram thereby to reproduce a data signal and detect an error signal. CONSTITUTION:A reproducing beam 12 emitted from a reproducing beam light source 7 is separated by using a hologram 3. It is so constituted that a 0-order diffraction light of the reproducing beam 12 in the returning path is eclipsed by an objective lens, and the first-order diffracted light 12b is converged onto a data recording medium. Tone reflecting light of the first-order diffracted light 12b is separated by the hologram 3 again. A data reproducing signal and an error signal are thus detected with the use of the 0-order light 12c of the reflected light. |
