GB1380725A - Optical gauging systems - Google Patents
Optical gauging systemsInfo
- Publication number
- GB1380725A GB1380725A GB1411271A GB1411271A GB1380725A GB 1380725 A GB1380725 A GB 1380725A GB 1411271 A GB1411271 A GB 1411271A GB 1411271 A GB1411271 A GB 1411271A GB 1380725 A GB1380725 A GB 1380725A
- Authority
- GB
- United Kingdom
- Prior art keywords
- radiation
- chopper
- plates
- source
- sectors
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 230000003287 optical effect Effects 0.000 title abstract 2
- 230000005855 radiation Effects 0.000 abstract 8
- 230000003595 spectral effect Effects 0.000 abstract 5
- 239000000463 material Substances 0.000 abstract 3
- 238000010438 heat treatment Methods 0.000 abstract 1
- 239000002184 metal Substances 0.000 abstract 1
- 238000005070 sampling Methods 0.000 abstract 1
- 239000000126 substance Substances 0.000 abstract 1
- 230000001360 synchronised effect Effects 0.000 abstract 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
- G01B11/06—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
- G01B11/06—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material
- G01B11/0616—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material of coating
- G01B11/0625—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material of coating with measurement of absorption or reflection
- G01B11/0633—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material of coating with measurement of absorption or reflection using one or more discrete wavelengths
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/314—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry with comparison of measurements at specific and non-specific wavelengths
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J1/00—Photometry, e.g. photographic exposure meter
- G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
- G01J2001/4242—Modulated light, e.g. for synchronizing source and detector circuit
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/12—Generating the spectrum; Monochromators
- G01J2003/1226—Interference filters
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
- G01N21/3554—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for determining moisture content
- G01N21/3559—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for determining moisture content in sheets, e.g. in paper
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
Abstract
1380725 Photo-electric gauging apparatus INFRARED ENG Ltd 20 July 1972 [10 May 1971] 14112/71 Heading G1A In an optical gauging apparatus radiation from a source is formed into two beams having different spectral wavelengths both of which are modulated by relatively movable elements having path defining means a plurality of which simultaneously pass parts of each beam, the beams are directed to a sampling region from which the radiation is received by a detector to produce an electrical signal which is synchronously demodulated. As shown Fig.1, radiation from an IR source S is passed through a chopper B and then through one of two interference filters F and G of different spectral wavelengths presented alternately. The resulting beam is reflected from a sample J, received by an elliptical or parabolic mirror and directed on to a detector the signal from which is synchronously demodulated to produce signals corresponding to the two spectral wavelengths. These signals may be combined to produce a measure of a property of the sample e.g. moisture content, thickness, concentration of individual elements, weight per unit area, and thickness of moisture or ink films on a surface. A filter may be placed in front of the detector to reduce interference from background radiation. The chopper comprises two plates each having a large number (e.g. 50 to 150) of alternate transparent and opaque sectors, one of the plates being rotatable relative to the other so that a radiation beam of larger diameter than the widths of the sectors at the point of incidence is alternately passed and blocked as the plate sectors move into and out of alignment. The filter plate W may be rotated together with the movable chopper plate so that a series of pulses at one spectral frequency are followed by a series of pulses at the other spectral frequency. The chopper may alternatively be of the reflective type in which the sectors of the plate remote from the source are alternately absorbing and reflective. The radiation source may be a filament lamp, an exposed heating filament, a Nernst filament or a Globar. A reference radiation beam may be passed through a portion of the chopper not utilized by the main beam to obtain the switching waveform for the synchronous detectors. The chopper plates may be of opaque material on a transparent substance or may be stamped or otherwise formed from a metal or other opaque sheet material, circular strengthing bars being provided if required. In a second embodiment, Figs.3 and 4 (not shown), radiation from the source passes through fixed filters and the resulting beams are chopped at different frequencies by a single device comprising a pair of plates one of which is rotated relating to the other arranged so that one beam passes through a region of outer annular portions of the plates which have larger numbers of alternate transmissive and opaque segments than do the inner portions through a region of which the other beam passes. The sample may be investigated with respect to the light reflected transmitted or backscattered and a diffuser, which may be made of the same material as the sample, may be mounted in front of the receiver.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB1411271A GB1380725A (en) | 1971-05-10 | 1971-05-10 | Optical gauging systems |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB1411271A GB1380725A (en) | 1971-05-10 | 1971-05-10 | Optical gauging systems |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1380725A true GB1380725A (en) | 1975-01-15 |
Family
ID=10035211
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB1411271A Expired GB1380725A (en) | 1971-05-10 | 1971-05-10 | Optical gauging systems |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB1380725A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2596509A1 (en) * | 1986-04-01 | 1987-10-02 | Chugai Ro Kogyo Kaisha Ltd | APPARATUS FOR MEASURING THE THICKNESS OF A LAYER ON A SURFACE, A PAINT LAYER FOR EXAMPLE |
FR2680240A1 (en) * | 1991-08-07 | 1993-02-12 | Siderurgie Fse Inst Rech | Method for continuously measuring the thickness of a film of oil on the surface of sheet metal advancing through a cold rolling installation |
WO2004061438A1 (en) * | 2002-12-26 | 2004-07-22 | The Boeing Company | Method for determining the surface cleanliness with infrared spectroscopy |
-
1971
- 1971-05-10 GB GB1411271A patent/GB1380725A/en not_active Expired
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2596509A1 (en) * | 1986-04-01 | 1987-10-02 | Chugai Ro Kogyo Kaisha Ltd | APPARATUS FOR MEASURING THE THICKNESS OF A LAYER ON A SURFACE, A PAINT LAYER FOR EXAMPLE |
FR2680240A1 (en) * | 1991-08-07 | 1993-02-12 | Siderurgie Fse Inst Rech | Method for continuously measuring the thickness of a film of oil on the surface of sheet metal advancing through a cold rolling installation |
US6956228B2 (en) | 2002-06-13 | 2005-10-18 | The Boeing Company | Surface cleanliness measurement with infrared spectroscopy |
WO2004061438A1 (en) * | 2002-12-26 | 2004-07-22 | The Boeing Company | Method for determining the surface cleanliness with infrared spectroscopy |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PS | Patent sealed | ||
PE20 | Patent expired after termination of 20 years |