WO1987003957A1 - Opto-electronic process for inspecting surfaces - Google Patents

Opto-electronic process for inspecting surfaces Download PDF

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Publication number
WO1987003957A1
WO1987003957A1 PCT/CH1986/000175 CH8600175W WO8703957A1 WO 1987003957 A1 WO1987003957 A1 WO 1987003957A1 CH 8600175 W CH8600175 W CH 8600175W WO 8703957 A1 WO8703957 A1 WO 8703957A1
Authority
WO
Grant status
Application
Patent type
Prior art keywords
characterized
information
principle
method
according
Prior art date
Application number
PCT/CH1986/000175
Other languages
German (de)
French (fr)
Inventor
Wilfried Schoeps
Original Assignee
Sin/Schweiz. Institut Für Nuklearforschung
Priority date (The priority date 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 date listed.)
Filing date
Publication date

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Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using infra-red, visible or ultra-violet light
    • G01N21/84Systems specially adapted for particular applications
    • G01N21/88Investigating the presence of flaws or contamination
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01BMEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00Measuring arrangements characterised by the use of optical means
    • G01B11/30Measuring arrangements characterised by the use of optical means for measuring roughness or irregularity of surfaces
    • G01B11/303Measuring arrangements characterised by the use of optical means for measuring roughness or irregularity of surfaces using photoelectric detection means

Abstract

The process enables the inspection of large solid or liquid surfaces for the presence of microscopically small defects at a very high measurement speed. It is characterized by the use of several or many measurement channels (schlieren optics) and by processing the information on defects on or in the surface investigated by means of suitable, possibly multi-stage, filters. It is thus possible to achieve measurement sensitivities and speeds which were hitherto impossible.

Description

OPT0 / ELEKTR0NISCHES METHOD FOR INSPECTION OF SURFACES

The object of the invention is to detect very small disturbances in solid and liquid surfaces and locate.

Through the arrangement of several or many measurement channels can inspect an unlimited Prakisch surface.

The method is suitable for. Ex. Very benign to detect faults already during the production process (in-line) and possibly to intervene in the process (control).

Since the process as explained below in some examples, uses no moving mechanical parts, the speed of inspection is practically limited only by the mechanical movement of the material to be inspected.

In Figure 1, a measurement channel is shown exemplary. In principle, it is a modified Schlieren optics. Punktfβrmigen from a light source 1, the emitted light is paralellisiert using a parabolic mirror. 2 It passes through a beam splitter 3, ansschliessend the strip mirror 4 and is incident perpendicularly on the examined surface 7. When the surface is entirely smooth and without interference, the light 7 through the open strip of "is 4 zυrflcklaufen the same route and at the beam splitter 3 divided and a portion falling on the detector. 5 a fault is located on the surface 7 9 (increase), so vird deflect the light in the range of the increase or the edges thereof. Part of the light now falls on the strips 4 and playful vird deflected to the detector. 6 If it is in disorder to many very small ErhOhungen v (roughness) so verden instead of one or several light beams many such deflected. It is thus possible to use the method described to for information Upper the basic roughness as well as individual disorders surfaces.

Figure 2 shows schematically the structure of a measurement channel with a possible arrangement of different filters for information processing. An alternating current generator 15 drives the punktfβr sodium lamp 1. The measuring channel 10 with the detectors 5 and 6 corresponds to the arrangement of Figure 1. The filter 11 described above may z.Bsp. cause a difference or a division of the two detector signals. 5 and 6 be the filters 12 and 13 can narrow-band amplifier tuned to the frequency of the generator 15. The evaluation circuit 14 (demodulator) removes the carrier frequency of the generator 15 and the information provides an upper βgliche disturbance under the measuring channel on the surface to be examined. 7

Figure 3 shows an arrangement as in Figure 2, the 16 has an additional detector for detecting punches. The signal from 16 is processed in a similar manner as the signals of 5 and 6. FIG.

In Figure 4, the known method of the synchronous demodulation is illustrated. The generator 15 is bit 14 coupled to the evaluation circuit. The information Upper interference from the evaluation circuit 14 can be used fflr the monitoring, display, storage, control and automation means of suitable electronic / informations¬ technical apparatus.

With the described method, a substantial increase in sensitivity can be achieved while improving greatly the measurement speed.

In multilateral or multi-channel configurations fflr large to be examined surfaces additionally has a certain redundancy, as can be measured in case of failure a measuring channel with at least the other continues. This principle is z.Bsp. very widespread in nature. Applying today's standard technologies fflr the measurement channels and the information processing, so also arise very kostengüns strength solutions.

Claims

OPTO / ELECTRONIC METHOD FOR INSPECTION OF OBERFLAECHENPatentansprüche
1. A method for the inspection of large surfaces, characterized in that very small objects disorders, irregularities, asperities etc, hereinbelow referred to kβnnen disorders, are detected with a very high speed.
2. The method of claim 1, characterized in that the inspected surfaces have solid or liquid character can.
3. Process according to claims 1 and 2 characterized in that different physical principles are in a suitable manner (multi-stage) combined to achieve a sensitivity not previously achieved.
4. Process according to claims 1 in to 3. The fact that the investigated surface and the disturbances are optically observed by means of one or more measurement channels, consisting of a Schlieren optics and one or more opto / electronic detectors, and that the information contained on the interference is worked up using one or more of additional electronic information filter to increase the measurement sensitivity.
5. The method according Ansprflchen 1. characterized to 4 that it is in the filtering information according to claim 4 to concerns filters that work up the information from one or more detector signals. Be the filter can of the type: the principle of difference and sum formation, according to the principle of the division / multiplication (normalization) on the principle of interference formation, according to the principle of the narrow-band carrier frequency technology, the principle of synchronous - demodulation. All filters can contain amplifiers.
6. The method according Ansprflchen 1. characterized to 5 that the surfaces to be examined is limited by a very large Geschwindigkei, only by the speed of the moving material, can move at the at the 4th and 5th Ansprflchen mentioned arrangement past when the method uses no mechanically moving parts.
7. Process according to claims 1 to 6 characterized In that the information obtained about the disturbances to monitor, display, storage, control and automation can be used by means of suitable electronic / information technology equipment.
PCT/CH1986/000175 1985-12-17 1986-12-15 Opto-electronic process for inspecting surfaces WO1987003957A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CH5363/85-2 1985-12-17
CH536385A CH669663A5 (en) 1985-12-17 1985-12-17

Publications (1)

Publication Number Publication Date
WO1987003957A1 true true WO1987003957A1 (en) 1987-07-02

Family

ID=4292308

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CH1986/000175 WO1987003957A1 (en) 1985-12-17 1986-12-15 Opto-electronic process for inspecting surfaces

Country Status (2)

Country Link
EP (1) EP0250490A1 (en)
WO (1) WO1987003957A1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2626383A1 (en) * 1988-01-27 1989-07-28 Commissariat Energie Atomique Method of scanning confocal optical microscopy and has extended depth of field and devices for implementation of METHOD
WO1990005297A1 (en) * 1988-10-31 1990-05-17 Schweizerische Eidgenossenschaft Psi Paul Scherrer Institut A device for the simultaneous contactless testing of a plurality of points on a test sample and its application
US5357283A (en) * 1989-01-19 1994-10-18 Tesler Vladimir E Reflected modulated television system

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10125751C2 (en) * 2001-05-18 2003-04-03 Willing Gmbh Dr Ing Light for matching of surfaces

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
LU56099A1 (en) * 1967-05-18 1970-01-14
US3736065A (en) * 1972-05-09 1973-05-29 Philco Ford Corp Radiation sensitive means for detecting optical flaws in glass
GB2025041A (en) * 1978-06-27 1980-01-16 Domtar Inc Graininesssensor
FR2491615A1 (en) * 1980-10-04 1982-04-09 Gast Theodor Optoelectronic measuring method and devices for the determination of the quality of a diffusely reflecting
DE3428435A1 (en) * 1984-08-01 1986-02-06 Sick Optik Elektronik Erwin Roughness probe

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
LU56099A1 (en) * 1967-05-18 1970-01-14
US3736065A (en) * 1972-05-09 1973-05-29 Philco Ford Corp Radiation sensitive means for detecting optical flaws in glass
GB2025041A (en) * 1978-06-27 1980-01-16 Domtar Inc Graininesssensor
FR2491615A1 (en) * 1980-10-04 1982-04-09 Gast Theodor Optoelectronic measuring method and devices for the determination of the quality of a diffusely reflecting
DE3428435A1 (en) * 1984-08-01 1986-02-06 Sick Optik Elektronik Erwin Roughness probe

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2626383A1 (en) * 1988-01-27 1989-07-28 Commissariat Energie Atomique Method of scanning confocal optical microscopy and has extended depth of field and devices for implementation of METHOD
EP0327425A1 (en) * 1988-01-27 1989-08-09 Commissariat A L'energie Atomique Method for optical scanning microscopy in confocal arrangement with large depth of field and apparatus to perform this method
US4965441A (en) * 1988-01-27 1990-10-23 Commissariat A L'energie Atomique Method for the scanning confocal light-optical microscopic and indepth examination of an extended field and devices for implementing said method
WO1990005297A1 (en) * 1988-10-31 1990-05-17 Schweizerische Eidgenossenschaft Psi Paul Scherrer Institut A device for the simultaneous contactless testing of a plurality of points on a test sample and its application
US5357283A (en) * 1989-01-19 1994-10-18 Tesler Vladimir E Reflected modulated television system

Also Published As

Publication number Publication date Type
EP0250490A1 (en) 1988-01-07 application

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