| 摘要 |
1. The device for selecting information layers in an optical recording medium is equipped with a radiation source, a system of selective focusing of the radiation beam generated by the radiation source on separate information layers, and a regulating system. The latter contains a detection system, which contains a radiation-sensitive surface, which receives the radiation beam. Characterized in that: The radiation-sensitive surface (16a, 16b, 16c, 16d) has the largest size within the range between 1.5 and 3 diameters of the radiation spot (19), produced on the radiation-sensitive surface by the radiation [reflected by] the recording medium, when the radiation beam is optimally focused on the information layer to be selected.
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