| 摘要 |
An optical pickup apparatus comprises: a laser light source for emitting a laser beam; a collimating optical system, having a first optical axis and a predetermined unsatisfied degree of a Abbe's sine condition, for collimating the laser light beam; an objective lens, having a second optical axis, for focusing the laser beam from the collimating optical system on an information holding plane of an optical disc; a detection portion for detecting an amount and a direction of a tilt of the optical disc from a reference; and a control portion for changing the first optical axis with respect to the second optical axis in accordance with the detected amount and direction of the tilt. A lens system of the collimating optical system is made to have an unsatisfied Abbe's sine condition to a predetermined degree and the optical axis of the lens system is tilted or shifted to compensate the comma aberration developed due to the tilt of the optical disc. Thus, it is sufficient to shift or tilt the optical axis of only the lens system by an actuator, so that a mass of optical components to be controlled is small. Therefore, a high frequency response is provided and the tilt servo in the tangential direction of the optical disc is provided. An optical disc apparatus using the optical pickup apparatus is also disclosed.
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