Patent ID: 7796486
Filing Date: 2010-09-14
Classification: G11B

Abstract:
1. A holographic optical information reproducing apparatus comprising: an objective lens configured to irradiate a reference beam to a predetermined position on a recording medium and configured to receive a reproducing beam reproduced from the recording medium; an optical information detector configured to detect the reproducing beam passing through the objective lens; a driving unit configured to change a distance between the optical information detector and the objective lens; and an image adjusting unit comprising four relay lenses and being disposed in an optical path of the reproducing beam, the image adjusting unit configured to adjust a magnification and a focus of an image by moving one of the four relay lenses, the image accurately being formed between an output image resulting from the reproducing beam passing through the objective lens and a detected image detected by the optical information detector with variation in distance to a predetermined position between the optical information detector and the objective lens despite a movement of the optical information detector and the objective lens by the driving unit, wherein a moving lens of the four relay lenses locates between one of the four relay lenses located at the most adjacent to the optical information detector and a relay lens located at the most adjacent to the objective lens, and wherein the four relays lenses are convex lenses.