| 摘要 |
PURPOSE:To ensure the stabilized recording and reproducing actions with an optical head by setting the light emitting points of the semiconductor lasers excluding the one set on the optical axis of a collimator lens with prescribed level differences secured in the direction of the optical axis of the collimator lens against the light emitting point of the semiconductor laser set on the optical axis of the collimator lens. CONSTITUTION:The light emitting points 33a and 33c of laser diodes LD3a and 3c are set with level differences secured in the direction of an optical axis against the light emitting point 33b of an LD3b so that the bend of an image surface due to a focusing optical system is corrected. Both points 33a and 33c are not set on the optical axis of a collimator lens 4 and therefore the light beams emitted from the points 33a and 33c and transmitted through the lens 4 and a focusing lens 8 are made incident obliquely on the lenses to cause the bends of the image surfaces. These image surfaces, however, are connected to each other on the same plane of an optical disk 9 owing to a level difference (d). As a result, three beam spots sent from the points 33a-33c on the disk 9 are even to secure the stable recording and reproducing actions.
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