OPTICAL INFORMATION RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To make a photodetector for position detection (position detection circuit) normally operate even when signal detection by a photodetector (PD) requires light intensity larger than that to CCD and CMOS sensors. SOLUTION: In an optical information recording medium having a structure with a waveguide hologram laminated, the area of the waveguide hologram for position detection of a light incident position to a waveguide is larger than the light receiving area of the photodetector for position detection, and diffracted light from the waveguide hologram for position detection lies almost within the light receiving surface of the photodetector for position detection at the position of the photodetector for position detection. COPYRIGHT: (C)2005,JPO&NCIPI