| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical pickup device capable of removing stray light by a simple configuration.SOLUTION: Mutually different astigmatism actions and advancing direction changing actions are imparted to luminous fluxes in four luminous flux regions A-D set around a laser optical axis of laser light reflected with a disk, and luminous fluxes of the luminous flux regions A-D are dispersed with one another. A signal light region in which only signal light exists appears on a detection surface of a photodetector, and a photodetector 112 having a sensor pattern is set in this region. A flat plate element 111 is set so as to be inclined with respect to an optical axis of reflected light. Thereby an astigmatism effect is produced without using any anamorphic lens. Consequently return path magnification can be minimized, and downsizing and simplification of the optical pickup device is achieved. |
