| 摘要 |
PURPOSE:To independently and stably execute each detection of focusing and tracking and to obtain a compact optical head by using a hologram, for which respective wave surfaces are written overlapped to a coherent. CONSTITUTION:An outgoing light beam L5 of a light source 6 is made to be parallel light by a lens 7 and transmitted through a hologram 8. After that, the beam is condensed on a disk 10 by an objective lens 9 and the reflected light is incoming through the lens 9 to the phologram 8. A primary refracting light L6 in the hologram 8 is incoming to a detector 11. The refracting light 6 from areas e1-e3 of the hologram 8 is incoming over detectors S1-S4 and a focus error signal can be obtained. A tracking error signal can be obtained from detector S5 and S6. |
