| 摘要 |
<p>In order to generate a lens position signal (LCE), which describes the position of the optical axis of an objective lens (6) of an apparatus for reading from and/or writing to an optical recording medium (7) with regard to the optical axis of the remaining components (2, 3, 4, 5, 8, 9) contained in an optical scanner (21), the application of the DPP method is proposed in accordance with a first exemplary embodiment, wherein a primary-beam error signal (CPP) and a secondary-beam error signal (OPP) are obtained with the aid of the DPP method, wherein the desired lens position signal (LCE) is generated by addition of the primary-beam error signal (CPP) and the secondary-beam error signal (OPP). In accordance with a second exemplary embodiment, it is not necessary to generate a primary beam, rather it suffices to detect the secondary beams reflected from the optical recording medium (7) in order to obtain the lens position signal (LCE) by addition of the secondary-beam error signals (OPP1, OPP2) generated in a manner dependent thereon.</p> |
