| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical pickup, an optical information recording/ reproducing device and a focus control method attaining stabilization of characteristics even in a system having no distance margin between an objective lens and a recording medium, and even in the case of being used under the environment where the impact from the outside is large. SOLUTION: The optical pickup 10 is provided with a main optical path that a light beam emitted from a 650 nm laser 12 goes and returns between a beam splitter 14, etc., a two group objective lens 22 and an optical disk OD, and finally arrives at a photo-detector 26 through a multi-lens 24, and a second optical path (sub-optical path) where the light beam emitted from a 780 nm laser of a 780 nm laser coupler 28 goes and returns between a collimater B30, etc., the two group objective lens 22 and the optical disk OD, and finally arrives at the photodiode of the 780 nm laser coupler 28. The pickup 10 generates a focus error signal FCS2 whose draw back range is large and an objective lens moving amount signal LS by the sub-optical path. |
