Patent ID: 8593926
Filing Date: 2013-11-26
Classification: G03H,G11B

Abstract:
1. An information storage device comprising: an information recording medium; at least a single light source that emits laser light; an illuminating unit that illuminates substantially the same position of the information recording medium with two light rays generated from the laser light, in different directions; a servo mark that reflects the two light rays is formed on the information recording medium; an image sensor unit that detects reflection light of the two light rays reflected from the servo mark and outputs an image signal; an operation unit that calculates position error information of the information recording medium based on a pair of the coordinate information of a center position of servo mark reflection spot images from the image signal, wherein the pair of the coordinate information that the information recording medium is located at a reference position and at a current position are used to calculate the position information; and a driving device that changes the position of the information recording medium based on the position error information.