EP0152979A1
Expired / Lapsed
EP
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Device for detecting differences in color
Assignee: Optische Industrie de Oude Delft NV
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Filing: 1985-02-06
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Granted: —
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Expires: 2005-02-06
Abstract
Abstract A device for detecting differences in color of a material to be inspected, which device comprises a first light source emitting light of a first color and a second light source emitting light of a second color, an optical system adapted to project portions of the light emitted both by the first and the second light source onto first and second spaced apart measuring regions respectively, each measuring region being associated with means for measuring the amount of light reflected by the material. The device further comprises electronic switching means for alternately energizing the first and the second light source, means for transporting the material, means for controlling the intensity of the second light source in dependence upon the measured amount of reflected first light source light, and means for determining a diference in color from the measured amounts of reflection.
Inventors
- 👤 Johannes Breemer
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-27 22:03
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/25; G01N21/31; G01N21/314; G01N21/3151; G01J; G01J3/00; G01J3/46; G01J2003/466; G01J3/50; G01J3/501; G01N21/84; G01N21/8483
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
199 words
A device for detecting differences in color of a material to be inspected, which device comprises means for illuminating the material, means for measuring the amount of light reflected by the material and means for transporting the material, characterized in that the means for illuminating the material include a first light source adapted to emit light of a first color and a second light source adapted to emit light of a second color, there being provided an optical system adapted to deliver portions of the light emitted by both the first and the second light source to first and second spaced apart measuring regions respectively, each measuring region being associated with means for measuring the amount of light reflected by the material, there further being provided means adapted to directly measure the amount of light emitted by the second light source, and there being provided electronic switching means for alternately energizing the first and the second light source, and electronic control means responsive to the measured amounts of reflected first light source light and reflected second light source light for so controlling the intensity of the second light source that the measured amounts of reflected light are substantially equal.
Claim 2
Independent Claim
199 words
A device for detecting differences in color of a material to be inspected, which device comprises means for illuminating the material, means for measuring the amount of light reflected by the material and means for transporting the material, characterized in that the means for illuminating the material include a first light source adapted to emit light of a first color and a second light source adapted to emit light of a second color, there being provided an optical system adapted to deliver portions of the light emitted by both the first and the second light source to first and second spaced apart measuring regions respectively, each measuring region being associated with means for measuring the amount of light reflected by the material, there further being provided means adapted to directly measure the amount of light emitted by the second light source, and there being provided electronic switching means for alternately energizing the first and the second light source, and electronic control means responsive to the measured amounts of reflected first light source light and reflected second light source light for so controlling the intensity of the second light source that the measured amounts of reflected light are substantially equal.
Claim 3
Dependent Claim
82 words
A device according to claim 1, characterized in that there are provided means for determing the difference in the reflection of light by the material at the two measuring regions by calculating the ratio between the amount of light emitted by the second light source when illuminating the first measuring region and that when illuminating the second measuring region, and that there are provided means adapted to produce an alarm signal in response to a predetermined value of said ratio being exceeded.
Claim 4
Dependent Claim
42 words
A device according to claim 1 or 2, characterized in that the optical system is adapted to deliver the light emitted by the first and the second light source respectively in equal portions to the first and the second measuring region respectively.
Claim 5
Dependent Claim
78 words
A device according to claim 1, 2 or 3, characterized in that the light sources are light emitting diodes and the detection means are silicon photodiodes, that the color of the first light source is green and the color of the second light source is red, and that the means directly measuring the amount of light emitted by the second light source likewise include a photodiode and are provided with a filter operative to optimally block green light.
Claim 6
Dependent Claim
108 words
A device according to claim 4, characterized in that a diffusor is mounted in front of the light emitting diodes, that the light emitting diodes and the diffusor are mounted in a housing having an aperture from which the light emitted by the light emitting diodes emanates, and that there is provided an objective for converting the divergent light beam emanating from the aperture into a parallel light beam, a portion of which parallel beam is passed through additional optical means to both measuring regions and another portion of which is projected onto the means for directly measuring the amount of light emitted by the second light source.
Claim 7
Dependent Claim
33 words
A device according to claim 4 or 5, characterized in that there are provided one red light emitting diode and n green light emitting diodes symmetrically arranged around the red light emitting diode.
Claim 8
Dependent Claim
12 words
A device according to claim 6, characterized in that n = 6.
Claim 9
Dependent Claim
77 words
A device according to claim 1 or 2, characterized in that the switching means are adapted to energize only the first light source during a predetermined period of time, the output signal of the means for directly measuring the amount of light emitted by the second light source being a measure for the offset current and the dark current of said means, and that there are provided memory means for storing the value of said output signal.
References Cited (Backward Citations)
US4032297A
Cited
DE2626600C2
Cited
WO1981002633A1
Cited
US4407290A
Cited
US4407290B1
Cited
US4379233A
Cited
WO1984000211A1
Cited
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