Device for correcting signal modulations

Abstract

A device for reading from and / or writing to optical recording media 10, on which information is present in the form of pits, with a linearly polarized light beam 2. A device for reading from and / or writing to optical recording media 10 which ensures correct reproduction of the stored data even when the recording medium influences the polarization of the light beam 2. This is achieved by virtue of the fact that a device for reading from and / or writing to optical recording media 10 with a light beam 2 which is linearly polarized in a first direction of polarization has a beam-splitting element 40 for splitting the light beam 2 into partial beams 21, 22, 23 in accordance with the first and a second direction of polarization, perpendicular to the first direction of polarization, and that it has a partly reflecting element 3, which directs both the partial beam 21 of the first direction of polarization and the partial beam 22, 23 of the second direction of polarization onto a detector unit 9, which has separate detector elements 91, 92, 93 for the partial beams 21, 22, 23 of the two directions of polarization.

Description

technical field [0001] The invention relates to a device for reading and / or writing to an optical recording medium on which information is present in the form of pits. Background technique [0002] Devices of this type are used, for example, for compact discs (eg CD, CD-R, CD-RW...) or digital versatile discs (in particular DVD, DVD-ROM, DVD-RAM, DVD+RW, DVD-RW... ) for reading and / or writing, on the latter the information is present in the form of structures with changing reflective properties, so-called pits. For this purpose, typically a laser diode emits a linearly polarized beam which passes through a polarizing beamsplitter cube and is collimated by a collimating lens. After the polarizing beamsplitter cube, the beam passes through a quarter-wave plate, whereby the beam is circularly polarized and focused onto the recording medium by a converging lens. A portion of the beam is reflected from the recording medium, and the intensity of the reflected beam depends on whe...

AI Technical Summary

Problems solved by technology

This can cause problems when reading out stored data if the variation exceeds a predetermined tolerance

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