WO1988004422A1 - Dispositif de controle de surface - Google Patents

Dispositif de controle de surface Download PDF

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Publication number
WO1988004422A1
WO1988004422A1 PCT/DE1987/000573 DE8700573W WO8804422A1 WO 1988004422 A1 WO1988004422 A1 WO 1988004422A1 DE 8700573 W DE8700573 W DE 8700573W WO 8804422 A1 WO8804422 A1 WO 8804422A1
Authority
WO
WIPO (PCT)
Prior art keywords
radiation
sensor
radiation source
tested
workpiece
Prior art date
Application number
PCT/DE1987/000573
Other languages
German (de)
English (en)
Inventor
Günter HEGE
Michael Struck
Original Assignee
Robert Bosch Gmbh
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
Application filed by Robert Bosch Gmbh filed Critical Robert Bosch Gmbh
Publication of WO1988004422A1 publication Critical patent/WO1988004422A1/fr

Links

Classifications

    • 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
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • 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
    • G01B11/30—Measuring arrangements characterised by the use of optical techniques for measuring roughness or irregularity of surfaces
    • G01B11/303—Measuring arrangements characterised by the use of optical techniques for measuring roughness or irregularity of surfaces using photoelectric detection means

Definitions

  • the invention relates to a surface testing device according to the preamble of the main claim.
  • a device for the automatic inspection of surfaces is already known.
  • a radiation source is provided, the focused radiation of which is guided over a workpiece surface, the radiation reflected from the surface being evaluated according to certain criteria for the surface quality.
  • the reflected radiation strikes, on the one hand, a radiation receiver in the bright field and, on the other hand, a plurality of radiation detectors arranged in the same plane around the bright field detector, which detect the total angular distribution of the radiation backscattered from the workpiece surface in terms of amount and direction . Damage to the workpiece surface changes the radiation reflected in the dark field or bright field.
  • the surface inspection device has the advantage that color deviations of the material of the surface to be inspected are recognized.
  • a radiation source is provided which emits radiation of a predetermined frequency lying in the optical frequency range. Part of the radiation reflected from the surface to be tested is directed at a radiation detector which emits an output signal proportional to the irradiance to an evaluation device. The direction of the radiation reflected by the surface to be tested is detected by a radiation detector which delivers a signal dependent on the point at which the radiation hits the detector to the evaluation device.
  • a color deviation is recognized in the evaluation device by comparing the recorded measured values with stored comparison values.
  • the measures listed in the subclaims enable advantageous further developments and improvements of the surface inspection device specified in the main claim.
  • An improvement in the color detection results if two radiation sources are provided which emit two radiations of different frequencies which can be predetermined in the optical range.
  • a detector is provided which emits a signal to an evaluation device which is proportional to the intensity of the radiation reflected from the surface to be tested at the one frequency, and a further detector is provided which sends a signal to the evaluation device emits that is proportional to the intensity of the radiation reflected from the surface to be tested at the other frequency.
  • a color contrast measurement is possible with the output signals of the two color-selective detectors.
  • Particularly suitable radiation sources are semiconductor lasers whose output power can be controlled within certain limits.
  • halogen lamps for example, can also be used in cost-sensitive systems, from the broadband emission spectrum of which the desired radiation components can optionally be selected using a pass-through filter.
  • Power regulation of the radiation sources has the advantage that strong fluctuations in intensity at the radiation detectors, caused by a strongly different reflecting surface of the parts to be tested, can be reduced to easily manageable values.
  • the surface inspection device uses the light section principle as the optical measuring method, which fulfills all requirements for detection and measurement of the surface defects to be expected.
  • a light beam or a light band is projected obliquely, preferably at an angle of less than or equal to 45 ° to the surface normal, onto the surface to be tested.
  • the profile curve of the surface is contained in the radiation reflected by the surface to be tested.
  • the angle of inclination between the incident radiation and the surface normal increases the resolution of the surface tester by increasing the profile line.
  • the light section method clearly reduces a three-dimensional geometry into a two-dimensional image, sequentially for the workpiece surface that is just illuminated by the light beam.
  • the surface of a three-dimensional workpiece can thus be checked.
  • at least a first movable mirror is provided, with which the incident radiation is guided in a cell shape or with another pattern over the surface to be tested.
  • a further rotatable mirror is arranged in the beam path of the reflected radiation, which enables the deflection of the reflected radiation to be adapted to the limited radiation detector areas.
  • a device for moving the workpiece to be tested can be provided. Further details and advantageous developments of the surface inspection device according to the invention result from further subclaims in connection with the following description.
  • FIG. 1 shows a structure of a surface inspection device according to the invention
  • FIG. 2 shows an incident and reflected radiation in the area of a surface to be tested.
  • Figure 1 shows a first and a second radiation source 10, 11.
  • the radiation 12 emitted by the second radiation source 11 is with a deflecting mirror 13 and a beam splitter 14 with that emitted by the first radiation source 10.
  • Radiation 15 combined into a light beam 16.
  • the term “light” is not intended to restrict the frequency range of the optical radiation 12, 15 emitted by the two radiation sources 10, 11 to the visible part of the optical frequency range.
  • the term “optical frequency range” is understood to mean the frequency range of the ultraviolet, visible and infrared radiation.
  • the two optical radiations 12, 15 each have a predetermined frequency.
  • Lasers which emit radiation of the desired frequency are advantageously used for the two radiation sources 10, 11.
  • Semiconductor lasers are particularly suitable since their output power can be easily controlled via a control circuit 17.
  • Thermal radiators, in particular halogen lamps, can also be used as an inexpensive alternative to lasers.
  • the desired spectral component of the broadband radiation emitted by the thermal radiators is transmitted with the aid of a
  • the light beam 16 passes through a beam-shaping device 20 and via a rotatable deflecting mirror 21 and via an imaging optics embodied as a collimating lens 22 as incident radiation 25 sharply focused onto a surface 23 of a workpiece 24 to be tested.
  • the radiation 30 reflected by the surface 23 arrives Via an imaging optics 31, which is preferably designed as a converging lens, and via a second rotatable mirror 32 onto a sensor arrangement 33.
  • the sensor arrangement 33 comprises a first radiation detector 34, which emits an output signal to an evaluation device 35 which is generated by the impact point of the reflected radiation 30 on an active surface 36 of the first sensor 34.
  • the reflected radiation 30 is imaged on the surface 36 of the first sensor 34 using a converging lens 37.
  • two beam splitters 38, 39 are arranged, which couple out part of the reflected radiation 30.
  • the radiation 40 coupled out by the first beam splitter 38 passes via a deflecting mirror 41 and a third color transmission filter 42 to a converging lens 43, which images the coupled radiation 40 onto a second radiation detector 44, which emits an output signal to the evaluation device 35, which is proportional to its irradiance.
  • the radiation 45 coupled out by the second beam splitter 39 passes via a further deflecting mirror 46 and a fourth color transmission filter 47 to a converging lens 48 which emits the coupled out radiation 45 images onto a third radiation sensor 49, which outputs an output signal to the evaluation device 35, which is proportional to its irradiance.
  • the evaluation device supplies output signals to three actuating devices 50, 51, 52.
  • the first actuating device 50 moves the first rotatable mirror 21 and the second actuating device 51 moves the second rotatable mirror 32.
  • Both rotatable mirrors 21, 32 are moved one by one Drawing plane of Figure 1 perpendicular axis in the two indicated arrow directions 53, 54 rotated.
  • the third adjusting device 52 moves the workpiece 24 in a plane parallel to the drawing plane in FIG. 1. The directions are shown by arrows 55.
  • the evaluation device 35 outputs signals to the control circuit 17, which controls the radiation power of the two radiation sources 10, 11.
  • the evaluation device 35 is connected to an evaluation and input unit 56, which on the one hand for the input of data and commands for the evaluation device 35 and on the other hand for the output of the measured values of the surface 23 to be tested determined by the evaluation device 35 of the workpiece 24 is provided.
  • FIG. 2 is a detailed image according to the section line II-II 'shown in FIG. 1, which shows the incident and reflected radiation 25, 30 between the two converging lenses 22, 31 in the region of the workpiece 24.
  • the parts that correspond in FIGS. 1 and 2 are each given the same reference numerals. registered.
  • the incident radiation 25 forms an angle of incidence 57 with the surface normal 59 on the surface 23 of the workpiece 24.
  • the radiation 30 reflected by the surface 23 forms an angle of incidence 58 with the surface normals 59.
  • the surface inspection device works as follows:
  • the light beam 16 is guided with the first rotatable mirror 21 in a cell shape or with any other pattern over the surface 23 of the workpiece 24.
  • the incident radiation 25 forms with the surface normal 59 of the surface 23 to be tested an angle of incidence 57 which is preferably less than or equal to 45 °.
  • the radiation 30 reflected by the surface 23 has a change in position during the scanning, which reflects the profile line of the surface 23. If the angle of incidence 57 is chosen to be approximately 45 °, then the angle of incidence 58 is likewise approximately 45 ° and the profile curve that appears appears excessive in the ratio of the root of 2 to 1.
  • This measuring method has long been known as a light section method in optical surface inspection technology (K. Räntsch: The optics in precision measurement, Kunststoff, Hanser, 1949).
  • the reflected radiation 30 reaches the active surface 36 of the first radiation sensor 34. Since the point of incidence of the incident radiation 25 on the surface 23 to be tested is known at all times, the point of incidence of the reflected radiation 30 on the first sensor 34 is also provided that one interference-free surface 23, given at any time by optical imaging relationships. A deviation of the position is determined by the evaluation device 35 by comparison with a "good" pattern and processed further. Statistics and / or output via input and output unit 56 then take place, for example.
  • the detectable surface 23 depends on the maximum possible deflections of the two rotatable mirrors 21, 32 and on the surface of the detectors 34, 44, 49.
  • a change in location of the reflected radiation on the first sensor 34, caused by the movement of the first rotatable mirror 21, is automatically taken into account in the evaluation in the evaluation device 35. From a certain position of the first rotatable mirror 21, the reflected radiation no longer strikes the active surface 36 of the first sensor 34.
  • the measurement range can then be expanded by the second rotatable mirror 32. At least with larger deflections by the first rotatable mirror 21, the reflected radiation 30 is tracked by the second rotatable mirror 32 in such a way that it always falls on the active surface 36 of the first sensor 34. Since the second rotatable mirror 32 is also controlled by the evaluation device 35 via the second actuating device 51, the position of the second rotatable mirror 32 is known at all times in the evaluation device 35 and can be taken into account when evaluating the measurement result.
  • Part of the reflected radiation 30 is coupled out by the beam splitter 38 and imaged on the second radiation sensor 44. However, only the radiation components which the third color transmission filter 42, which is matched to one of the two emitted radiations 12, 15, pass onto the second sensor 44. Part of the reflected radiation 30 is further masked out by the beam splitter 39, which is imaged on the third radiation sensor 49. Only those radiation components which the fourth color transmission filter 47, which is matched to the other of the two emitted radiations 12, 15, can pass onto the third sensor 49. Since the second and third sensors 44, 49 each output an output signal to the evaluation device 35 that is proportional to the irradiance, these two sensors 44, 49 change the intensity of the two radiation components 12, 15 in the reflected radiation 30 detected.
  • a change in the location of the reflected radiation 30 on the surfaces of the two sensors 44 and 49 has no effect on the measurement result, as long as the surface area on which the output signal is not left is proportional to the irradiance.
  • a change in the intensity of one or the other or both radiation components 12, 15 indicates a frequency-dependent reflection on the surface 23 to be tested if no change in position is detected by the first sensor 34 at the same time. From the determined relative change in the output signals of either the second sensor 44 or the third sensor 49 or a relative change in the ratio of the two signals to one another, a change in color of the surface 23 to be tested can be concluded.
  • a quantitative indication of color changes for example as changes in the color coordinates in the color triangle, can be displayed via the input and output device 56.
  • Another evaluation method is a neighborhood analysis, in which the position and color deviation of the reflected radiation 30 from one scanning point on the surface 23 to the next is detected and evaluated and compared with stored reference values.
  • a color change arises, in particular, from inclusions of foreign material in the surface 23 to be tested and, for example, from chemical or thermal influencing of the surface 23 of the workpiece 24. Such defects can be detected and displayed with the surface testing device according to the invention.
  • a simplified embodiment of the surface testing device according to the invention according to FIG. 1 is given if only one radiation source is provided instead of the two radiation sources 10, 11.
  • the sensor arrangement 33 contains the first radiation sensor 34, which detects the position of the reflected radiation 30, and a further radiation sensor, which measures the irradiance. In this arrangement, none of the color filters 18, 19, 42, 47 is required. A change in color of the surface 23 to be tested leads to a change in the intensity of the reflected radiation 30. If the first sensor 34 detects no change in position and, at the same time, the intensity of the reflected radiation 30 changes, a change in color in the surface 23 to be tested can be concluded at least qualitatively.
  • a further possibility for simplifying the surface testing device with a radiation source is given by using only a single radiation sensor. This sensor simultaneously detects both the point at which the reflected radiation 30 strikes the sensor 34 and the intensity. All types of one- or two-dimensional multi-sensor arrangements are suitable. Photo diode rows are preferably used.
  • more than two radiation sources can be provided, all radiation sources emitting radiation in the optical frequency range with frequencies different from one another.
  • the sensor arrangement 33 then contains further decoupling paths 40, 45 for the reflected radiation 30, which lead to color-selective radiation sensors 42, 44 and 47, 49, respectively. With this arrangement, an even more precise color analysis can be carried out.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (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 Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)

Abstract

Dans un dispositif servant à contrôler la surface (23) d'une pièce (24) tridimensionnelle, sont prévues deux sources de rayonnement (10, 11) qui émettent un rayonnement (12, 15) de fréquence donnée. Le faisceau lumineux (16) commun est dirigé sur la surface à contrôler (23) de la pièce (24), par l'intermédiaire d'un système de formation de faisceau (20) et d'un premier miroir rotatif (21) ainsi que d'une lentille de concentration (22). Le rayonnement (30) réfléchi par la surface (23) parvient sur un agencement de capteurs (33), après passage à travers une autre lentille convexe (31) et déflexion par un deuxième miroir rotatif (32). L'agencement de capteurs (33) comprend un premier capteur de rayonnement (34) qui délivre à un organe d'évaluation (35) un signal de sortie qui est fonction du point d'incidence, sur la surface active (36) du premier capteur (34), du rayonnement (30) réfléchi par la surface (23) de la pièce (24). Sont prévus deux autres capteurs de rayonnement (44, 49) qui délivrent à l'organe d'évaluation (35) un signal de sortie qui est fonction de l'intensité de rayonnement desdits capteurs (44, 49). En amont de ces derniers sont disposés des filtres perméables aux couleurs (42, 47), la plage passante d'un filtre (42) étant modulée sur la fréquence du rayonnement (15) de la première source de rayonnement (10), et celle de l'autre filtre (47) étant modulée sur l'autre fréquence du rayonnement (12) de la deuxième source de rayonnement (1). L'appareil décrit permet d'identifier automatiquement des défauts caractérisés par des configurations et des couleurs différentes sur la surface à contrôler (23) de la pièce (24).
PCT/DE1987/000573 1986-12-08 1987-12-04 Dispositif de controle de surface WO1988004422A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DEP3641863.3 1986-12-08
DE19863641863 DE3641863A1 (de) 1986-12-08 1986-12-08 Oberflaechenpruefvorrichtung

Publications (1)

Publication Number Publication Date
WO1988004422A1 true WO1988004422A1 (fr) 1988-06-16

Family

ID=6315699

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE1987/000573 WO1988004422A1 (fr) 1986-12-08 1987-12-04 Dispositif de controle de surface

Country Status (3)

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DE (1) DE3641863A1 (fr)
ES (1) ES2005965A6 (fr)
WO (1) WO1988004422A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5991017A (en) * 1995-06-15 1999-11-23 British Nuclear Fuels Plc Inspecting the surface of an object

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3819900A1 (de) * 1988-06-11 1989-12-14 Daimler Benz Ag Verfahren zur bestimmung der korrosionsstabilitaet von tiefziehfaehigen eisenblechen fuer karosserieteile von kraftfahrzeugen und vorrichtung zur durchfuehrung dieses verfahrens
DE4343058A1 (de) * 1993-12-19 1995-06-22 Robert Prof Dr Ing Massen Multisensorielle Kamera für die Qualitätssicherung
DE4434474C2 (de) * 1994-09-27 2000-06-15 Basler Ag Verfahren und Vorrichtung zur vollständigen optischen Qualitätskontrolle von Gegenständen
DE102009030644B4 (de) * 2009-06-25 2011-02-03 Gottfried Wilhelm Leibniz Universität Hannover Berührungslose Erfassungseinrichtung

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3917414A (en) * 1973-10-11 1975-11-04 Geisco Associates Optical inspection system
US4004153A (en) * 1974-07-12 1977-01-18 Erwin Sick Gmbh Optik-Elektronik Apparatus for monitoring a web of material
US4265545A (en) * 1979-07-27 1981-05-05 Intec Corporation Multiple source laser scanning inspection system
GB2085579A (en) * 1980-10-09 1982-04-28 Hitachi Ltd Apparatus for detecting defects in plates
US4520388A (en) * 1982-11-01 1985-05-28 General Electric Company Optical signal projector
GB2173294A (en) * 1985-04-02 1986-10-08 Glaverbel Determining the location of defects present in flat glass

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4352017A (en) * 1980-09-22 1982-09-28 Rca Corporation Apparatus for determining the quality of a semiconductor surface
US4532723A (en) * 1982-03-25 1985-08-06 General Electric Company Optical inspection system

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3917414A (en) * 1973-10-11 1975-11-04 Geisco Associates Optical inspection system
US4004153A (en) * 1974-07-12 1977-01-18 Erwin Sick Gmbh Optik-Elektronik Apparatus for monitoring a web of material
US4265545A (en) * 1979-07-27 1981-05-05 Intec Corporation Multiple source laser scanning inspection system
GB2085579A (en) * 1980-10-09 1982-04-28 Hitachi Ltd Apparatus for detecting defects in plates
US4520388A (en) * 1982-11-01 1985-05-28 General Electric Company Optical signal projector
GB2173294A (en) * 1985-04-02 1986-10-08 Glaverbel Determining the location of defects present in flat glass

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5991017A (en) * 1995-06-15 1999-11-23 British Nuclear Fuels Plc Inspecting the surface of an object

Also Published As

Publication number Publication date
ES2005965A6 (es) 1989-04-01
DE3641863A1 (de) 1988-06-09

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