Optimized Spatial Resolution for a Spectroscopic Sensor
AssigneeHoneywell ASCa Inc.
InventorFrank Martin Haran
Life of this patent
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Abstract
Scanning sensor for measuring properties of continuous flat sheet, that is moving in the machine direction, employs an IR radiation source for directing a beam of incident IR radiation that impinges the sheet. The IR source has elongated lamp filament that generates IR radiation and the corresponding spot size formed on the sheet has elongated dimensions with its long axis being aligned with the machine direction. Aligned with the MD maximizes sensor spatial resolution in the cross direction. The sensor can employ a receiver having rectangular geometry with its long axis being aligned also in the MD. Scanning sensor can operate in the reflective, transmissive, or offset transmission mode to monitor characteristics of flat sheets, particularly of paper or plastic products.
Claims20
A sensor for measuring at least one selected component in a continuous sheet composition having a length and width and that is moving in a machine direction (MD) which is parallel to the sheet length wherein the sheet has a first surface and a second surface that is opposite to the first side that comprises:
- an infrared (IR) radiation source for directing a beam of incident infrared radiation to the first surface of the sheet wherein the source has a filament that emits IR radiation having an elongated beam profile that impinges on the first surface with an impinging elongated profile;
- and
- a detector operable to receive IR radiation that emerges from the second surface of the sheet wherein (i) the impinging elongated profile has a length that is aligned parallel with the MD to maximize detector spatial resolution in the cross direction (CD) or (ii) the detector comprises at least one detector element having a length that is aligned parallel in the MD.
A system for continuous on-line measurement of a characteristic of a moving sheet that is traveling lengthwise in the machine direction (MD) comprises:
- an infrared (IR) radiation source which emits radiation from an elongated filament such that an incident elongated beam of IR radiation is directed on a first side of the sheet wherein the IR radiation source travels over the cross direction (CD) of the moving sheet;
- a receiver operable to detect radiation emerging from the moving sheet and provides electrical detection signals and wherein the receiver travels over the CD of the moving sheet wherein (i) the long axis of the elongated beam is aligned parallel with the MD or (ii) the receiver comprises at least one detector element having a length that is aligned parallel with the MD;
- and
- a processor that receives the electrical detection signals and that is operable to determine at least one property of the sheet.
A method of measuring at least one property of a sheet that is traveling lengthwise in the machine direction (MD) that comprises the steps of:
- (a) directing a beam of infrared (IR) radiation from an IR radiation source haying an elongated filament that emits IR radiation having an elongated beam profile at the moving sheet such that impinging IR radiation has an impinging elongated profile;
- (b) measuring radiation emerging from the sample and venerating electrical signals therefrom wherein (i) the impinging elongated profile has a length that is aligned parallel with the MD such that the orientation enhances the spatial resolution or (ii) step (b) employs a receiver that has at least one detector element having a length that is aligned parallel with the MD;
- and
- (c) determining at least one property of the sample from the electrical signals.
Dependencies are inferred from the claim text.