| 摘要 |
In a light-emitting section ( 2 ) for emitting semiconductor laser for CD ( 4 ) and semiconductor laser for DVD ( 5 ), a radiation angle width theta 2 of the DVD semiconductor laser ( 5 ) is at least 1.3 times a radiation angle width theta 1 of the CD semiconductor laser ( 4 ), said radiation angle width being defined as a width of an angle created by two straight lines, which extend respectively from a laser-emitting point to two points where a radiation intensity of laser becomes half of an intensity of the center of laser, which points reside within a plane parallel to a pn junction plane.
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