Frequency-selective optical data recording and data reproduction apparatus

摘要

The frequency-selective optical data recording and data reproduction apparatus generates a light beam which is directed at a recording medium (disk 5) and the wavelength of which sequentially assumes different values, the information bits being recorded or read at different wavelengths. In dependence on the wavelength, the light emitted from a plurality of light sources (LD1-LD4), the wavelengths of which belong to different wavelength bands, is projected along a predetermined light path and concentrated by means of a light concentration apparatus (107) to form a light spot on the recording medium for the purpose of recording and reproducing data. The light reflected by the recording medium is distributed by means of a distribution and concentration apparatus (108) in dependence on its wavelength simultaneously to various points, at which it is sensed by detectors. The light coming from the light sources (LD1-LD4) is polarised in a polarisation apparatus (105, 106) and concentrated on the recording medium. In the polarisation apparatus (105, 106), the light reflected by the recording medium is also polarised. <IMAGE>