Patent ID: 8699311
Filing Date: 2014-04-15
Classification: G11B

Abstract:
1. An optical-information reproducing apparatus for reproducing information from an optical-information storage medium where an interference pattern between a signal beam and a reference beam is recorded as page data by being angle-multiplexed, said optical-information reproducing apparatus, comprising: a light-source for emitting a light beam; an optical element for splitting said light beam into said reference beam and said signal beam; an angle-controlling element for controlling said reference beam into a direction which is perpendicular to an angle-multiplexed direction, said reference beam being guided to enter said optical-information storage medium; an optical detector for detecting a reproduced image which is reproduced by said reference beam; and a position-controlling circuit for controlling position relationship between said reference beam and said optical-information storage medium, wherein, said optical-information storage medium is illuminated with said reference beam in a state where angle of said reference beam is shifted from an angle which is suitable for said reproduction of said page data, said angle of said reference beam being directed to said direction which is perpendicular to said angle-multiplexed direction, light amount of said reproduced beam reproduced from said optical-information storage medium being detected by said optical detector, and presence or absence of a hologram at a position which is illuminated with said reference beam being detected based on information about said light amount detected.