| 摘要 |
First and second light sources, an objective optical element, a photo-detector, first and second coupling elements and a beam splitter are arranged such that a first light flux emitted from the first light source comes into the objective optical element through the first coupling element and the beam splitter and forms a converged light spot on an information recording plane of a first optical information recording medium, a second light flux emitted from the second light source comes into the objective optical element through the second coupling element and the beam splitter and forms a converged light spot on an information recording plane of a second optical information recording medium, and the first and second light fluxes forming the respective converged light spots are reflected from the respective information recording planes and thereafter pass through the objective optical element, the beam splitter and the second coupling element and come into the photo-detector.
|
