METHOD AND APPARATUS FOR REDUCING NOISE AT MAGNETOOPTICAL READERS

摘要

2. In the case of an optical pick-up device for reading and/or writing on an optical recording medium (5), the light reflected by the recording medium (5) or the light transilluminating the recording medium (5) is directed by means of a polarisation beam splitter (8) depending on its polarisation direction onto a first photodetector (11) or a second photodetector (17). In order to suppress to a great extent interfering components S(t) in the data signal (MS), the polarisation beam splitter (8) has to be adjusted accurately in the path of rays. 2.2 In order to be able to read magneto-optical recording media (5) of different optical characteristics without having to readjust the polarisation between splitter (8) each time, the intensity of the light reflected by the recording medium (5) or the light transilluminating the recording medium (5) is controlled to a constant value. Because the interfering components S(t) are corrected by this measure, it also dispenses with the need for accurate adjustment of the polarisation beam splitter (8) in the path of rays. 2.3 Magneto-optical equipment.