| 摘要 |
By using a two-beam optical head, simultaneous focusing of two light spots can be achieved and the execution of simultaneous erasure, recording and reproduction of information can be easily realized even in an inexpensive optical system which uses lenses having chromatic aberration. The two-beam optical head includes a monolithic semiconductor laser array having two light-emitting points which emit first and second light beams having different light intensities, and an optical system for forming first and second light spots on a magnetooptical disk. The two light beams pass along substantially the same optical path. The direction of the arrangement of the first and second light-emitting points of said light source unit is inclined with respect to a plane perpendicular to the optical axis of the optical system to focus the light spots on the same plane of the magnetooptical disk.
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