US 5,073,712 A · Light scanner web profile measurement apparatus and method

Abstract

A method and apparatus provide for determining properties of a web of traveling sheet material by scanning light including at least selected wavelengths such as IR and/or visible wavelengths across the web of material and also across at least two calibration samples. The signals generated in response to the scanning of the calibration samples is used to calibrate the scanning operation preferably on every scan. By providing at least two calibration samples, better estimates of average calibration parameters can be made and detection of a faulty calibration sample is facilitated. The calibration samples preferably are protected by mounting them within a scanner housing in relatively close proximity to a scanning beam generator. In addition, at least two compensation samples are supported substantially adjacent the moving web of material and preferably at least one compensation sample is positioned on each side of the web. By providing two compensation samples, fault conditions or fouling of either one of the compensation samples can be readily detected and also be used to better generate an average compensation signal. Compensation is particularly advantageous in accounting for ambient operating conditions of the process being used to manufacture the moving web of material. Both the calibration and compensation samples can be encapsulated in glass or other appropriate material to maintain their defined characteristics without effecting the monitoring operations of the optical scanner.

Claims20

Dependent claims

A system for determining light sensitive properties of a web of sheet material traveling in a first direction during its manufacture, said system comprising:

light source means for generating light including at least selected wavelengths;
light detector means for sensing light of at least said selected wavelengths and generating signals representative thereof;
scanner means for receiving light from said light source means and scanning the received light through a scanning arc which includes said web and traverses said web in a direction substantially perpendicular to said first direction;
calibration sample holder means for supporting at least two calibration samples substantially adjacent to said light scanner means and within said scanning arc;
light collector means for collecting light applied by said scanner means from said web and from said at least two calibration samples, and directing light collected therefrom onto said light detector means;
and
processor means connected to said light detector means for receiving said signals and determining said light sensitive properties of said web of sheet material therefrom.

4 more elements

A system for determining light sensitive properties of a web of sheet material traveling in a first direction during its manufacture, said system comprising:

light source means for generating light including at least selected wavelengths;
light detector means for sensing light of at least said selected wavelengths and generating signals representative thereof;
scanner means for receiving light from said light source means and scanning the received light through a scanning arc which includes said web and traverses said web in a direction substantially perpendicular to said first direction;
sample holder means for supporting at least two calibration samples within said scanning arc;
light collector means for collecting light applied by said scanner means from said web and from said at least two calibration samples, and directing light collected therefrom onto said light detector means;
and
processor means connected to said light detector means for receiving said signals and determining said light sensitive properties of said web of sheet material therefrom.

4 more elements

Dependencies are inferred from the claim text.

Light scanner web profile measurement apparatus and method

Life of this patent

Light scanner web profile measurement apparatus and method

Life of this patent

Abstract

Claims20