| 摘要 |
PROBLEM TO BE SOLVED: To make an optical system for recording or reproducing small and to reduce intensity change in reproducing light with respect to thickness of an information recording layer recording information by using holography. SOLUTION: At a recording time, a hologram layer 3 of an optical information recording medium 1 is irradiated by recording reference light from one surface side through an objective lens 12, and the other side surface is irradiated by information light through a coupling lens 50, and a reflection type hologram is formed. At a reproducing time, the hologram layer 3 of the optical information recording medium 1 is irradiated by reproducing reference light from one surface side through the objective lens 12, and the information light generated from the hologram layer 3 is converged by the objective lens 12 to be detected by a CCD array 15. |
