| 摘要 |
The present invention relates to a device for detecting the properties of a web of material transported in the longitudinal direction such as a paper web (20). The device includes a plurality of optical fibres (28) having their input areas (30) each located in the vicinity of the surface of the material web and aligned on said surface, the fibres being secured on a crossbar (26) extending across the material web. The device also includes an infrared spectrometer having the output areas (34) of the optical fibres (28) connected to its input (36) while infrared sensors are connected to the output (44) of said infrared spectrometer. The infrared spectrometer includes a holographic grating (40) for arranging the optical fibers (28) side by side and in one line at the spectrometer input (36) so that the infrared spectra of the signals emitted by the individual optical fibres (28) appear side by side in one line at the spectrometer output (44), and so that the infrared sensors at said output (44) are made in the form of a sensor matrix (46) comprising n lines and m rows of individual infrared-sensitive sensors (48), wherein the spectra from up to m optical fibres (28) can be distributed and detected into up to n spectral areas.
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