| 摘要 |
When an optical recording medium (7) having a plurality of data layers is being read from and/or written to, the input beam, inter alia in the top layers of the data layers. To achieve a high data density, a device (4) for correcting the spherical aberration is located in the beam path. When an optical diode is just in which the input and reflected beams have perpendicular directions of polarization, such a device (4) is expensive to implement and associated with a reduced optical efficiency. An apparatus for reading from and/or writing to optical recording media is proposed, in which high optical efficiency and balancing of the spherical aberration are achieved with low outlay. The device (4) for correcting the spherical aberration is set up such that the reflected beam traverses it uninfluenced, whereby means (12, 16, 19) for correcting the imaging of the reflected beam onto at least one detector unit (13, 15, 17, 18, 20) are provided in the further beam path.
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