US 7,382,456 B2 · Spectroscopic sensor for measuring sheet properties

Abstract

A spectroscopic sensor for measuring flat sheet product is disclosed. The disclosed sensor uses a combination of spectrometers and single-channel detectors and filters together with a broadband source of illumination to optimally measure multiple properties of a flat sheet product. A spectrometer is used to measure over a spectral range where an easily configurable set of wavelength channels is needed and where the signal-to-noise ratios and spectral resolutions of the channels are consistent with the spectral range and number of pixels of the spectrometer; while one or more single channel detector and filter combinations are used to measure, with high signal-to-noise ratio, at specific wavelengths within or outside the spectral range of the spectrometer(s). Therefore, the single channel detectors can be used to complement the information provided by a spectrometer or to extend the working range of a spectrometer by providing single wavelength measurements anywhere in the visible, near-IR or mid-IR spectral regions.

Claims18

Dependent claims

A sensor for measuring a plurality of characteristics of a flat sheet product, said sensor comprising:

a source for emitting radiation towards the flat sheet product;
a plurality of beam splitters arranged in series for splitting the radiation after the radiation interacts with the flat sheet product;
a plurality of bandpass filters for filtering the split radiation;
a plurality of single channel detectors, each channel detector being coupled to one bandpass filter;
and
at least one optical spectrometer, wherein the at least one optical spectrometer measures one or more characteristics of said plurality of characteristics of the flat sheet product using said split radiation received from a first beam splitter of said plurality of beam splitters, and each coupled channel detector and bandpass filter measures one or more characteristics of said plurality of characteristics of the flat sheet product using said split radiation received from one or more of said plurality beam splitters, said characteristics measured by each coupled channel detector and bandpass filter being different from said characteristics measured by said spectrometer.

3 more elements

Dependencies are inferred from the claim text.

Spectroscopic sensor for measuring sheet properties

Life of this patent

Spectroscopic sensor for measuring sheet properties

Life of this patent

Abstract

Claims18