SU1296837A1 - Device for checking geometric dimensions and flaws of specimens with dissipating surfaces - Google Patents

Description

to the separation scheme for analyzing the observation of the thickness tolerance in the electronic data processing circuit,

7. A device according to claims 2-6, characterized in that the line-type photodetectors are located in the image plane of the same imaging optics.

8. A device according to claims, characterized in that the main receiver is located in the image plane of the first imaging optics, and the secondary receivers are located in the image plane of the second imaging optics.

9. The device of claim 8 ,. characterized in that the optical axis of the first imaging optics makes a larger angle with the incident light than the optical axis of the second imaging optics.

10. A device according to claim 9, characterized in that an angle in the interval from 70 to 9 cm is formed between the optical axis of the first imaging optics and the geometric standard of the surface of the test sample.

11. The device according to claim 1, characterized in that the error receiver consists of at least two line-type photodetectors, one of which is the defet signaling unit and the other is the defect detector, the defect signaling unit is located in the image plane parallel to the main receiver, and the defect detector - also parallel to the main receiver, but at a greater distance from it.

12. An I1 device, characterized in that the defect signaling unit, separated by a distance zone, follows the main receiver and the defect detector with its edge directed towards the main receiver in the position corresponding to the deviation of the scan line image with an unacceptable depth of defects surface, and at the output of the defect signaling unit in the error analysis block, a block for determining the area of the defect is inserted to receive an error signal and a logical OR cell connected to a defect detector.

13. The device according to claim 12, characterized in that with the maximum expected depth of the defect

The sample surface of the reject detector range corresponds to the deviation of the scan line image.

14. The device according to Claims 11 and 13, which is noted for the fact that the defect detector is located directly in the defect signaling unit.

15. A device according to claims 2-14, characterized in that elongated photoelectric receiving elements made in the form of lines are used as line-type photodetectors.

16. A device as claimed in Claims 2-14, characterized in that a line slit diaphragm, focusing optics are placed next to it, and the focusing optics in its image plane — the receiving element with a slight spreading factor1.

17. A device according to nn, i-16, characterized in that a width signal receiver is inserted into it, which is connected to the valve circuits of the electronic data circuit block located in the output signal circuit.

18. A device according to claim 17, characterized in that, respectively, separate logic cells I. are located at the output of the thickness processing unit and the error analysis unit.

19. A device according to PP 17 and 18, characterized in that a photoelectric width signal receiver is used to display the width signal in the image plane of one of the reflecting optics to display the scanning line at each possible deviation.

20. The device according to Claim 1, which is based on the fact that a beam splitter is placed in front of the photoelectric receiving device, and a width signal receiver is placed in the image plane of the separated beam path behind the beam splitter.

21. A device according to Claims 1 and 20. characterized in that the imaging optics and the receiver of width signals are located in its plane in scattered light within the course of the rays in the lighting system,

22, Device according to claims 19-21, characterized in that the width signal receiver consists of a display optics for the signal element

width and located in its plane of the image of an active element with an insignificant coefficient of expansion.

23. The device according to claims 1-22, T - LI), in that the scanning beam of the illumination device is directed perpendicularly to the surface of the test specimen.

t

The invention relates to a device for checking defects and geometrical dimensions of samples with scattering surfaces, preferably a flat or cylindrical shape, with which the test can simultaneously determine the length, diameter and thickness, adherence to diameter and thickness tolerance of the test sample. surface error values such as holes, cracks, dimples, local mounds, as well as depth or high, holes, dimples and local mounds. The device is designed to determine deviations from 10 microns in a few millimeters and can be used to check and control samples, as well as detect a special defect: in, tolerances deviations and shapes of technical surfaces, taking into account the automation of these processes. The invention is used to control specimens with strongly diffusing and diffusely reflecting surfaces.

. A number of optical data devices are known for optical inspection of surface dimensions based on different ones. optical principles, with the device dp evaluating the light reflected from the surface of the test sample, are most common.

In the specification of U.S. Patent No. 3,788,771 H, Cl. 356-4, 1977, an optical probe consisting of a focusing lens, a semi-transmissive mirror, two light filters of different colors, two detectors and two light sources is presented. The evaluation of the surface and the depth of the defect is carried out by measuring the amount of light reflected from the surface.

24. A device according to claims 1 to 23, characterized in that a light source for point radiation and a deflecting unit are used as a lighting device for deflecting the light beam in rows along the scanning line of the test sample.

A device is known (patent BB) containing a lamp, a cylindrical lens and a series of light guides, the fiber optic being bundled and connected to a photocell. The ends of the light-guided cables are arranged as a string in the direction of light reflection. The evaluation of the surface is also carried out by comparing the intensity of the reflected light of individual photocells, which can be combined in different ways from the point of view of electrical engineering.

A device (German patent 2621238, cl. G 01 B 11/04, 1978) is known for determining the dimension of cylindrical objects, consisting of two driven rollers, 1 replenishment for an infrared diode and two phototransistors. During the test, the cylindrical object moves on the driven rollers between the infrared diode and the phototransistors and, depending on their diameter, turns them off so that the light intensity is a measure of the diameter,

However, the known devices are not designed for checking objects with strongly dissipating surfaces, for detecting surface errors and determining their depths, as well as the geometric dimensions of objects.

The purpose of the invention is to create a device with which, with high accuracy of measurement, non-contact monitoring of defects and their geometric dimensions is performed during the same verification process, while ensuring high performance. The device is used in automatically operating test equipment.

The invention is based on the task of creating a device with which it is controlled with high efficiency and without damage to the sample.

In a device for monitoring defects and geometrical dimensions of test samples with scattering surfaces consisting of a lighting device for optical scanning of a sample in rows, a motion transmission mechanism for sensitizing the relative movement between the scanning line and the test sample approximately perpendicular to the scanning diaphragm , and also from electronic processing circuits, this problem is solved by the fact that at least one of the optics displayed in the scattered light and its image in otoelectric receiver distributed along the image of the scanning line and consisting of a collapsible main receiver, receiving a display of the scanning line in its nominal position, and an error receiver, the main receiver containing several line-type photodetectors and at least two receivers in one of the blocks for processing tol1ainy in the data processing system follows a joint logical operation OR to control the thickness, while an error receiver is attached to the electronic block to for error handling, as there are two main receiver strochkoobraznyh photodetecting device, consisting of a main receiver, was collected the main part of the radiation ,, and a secondary receiver, which are arranged one beside another. As the main receiver, three line-type photodetector devices are used, consisting of an average main receiver collecting the main part of the radiation and two secondary 1.x receivers connected between the slots electrically placed one near the other. In addition, as the main receiver, the first line-type photodetector can also serve as a slot extending along the length of the line and immediately behind this slot the second line-type photodetector, the second photodetector being the heads

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The receiver receives the bulk of the luminous flux, and the first photodetector is treated as a secondary receiver.

It is possible to locate the main receiver directly in front of the slit of the first line-like photographic device. Secondary receivers located on both sides of the main receiver can respectively be connected to a separate analysis circuit in a common electronic processing circuitry system designed to control the non-observance (excess and non-use) of the thickness tolerance. Rowed photodetectors are located in the image plane of the same imaging optics or the main receiver is in the image plane first, and the secondary receiver is in the image plane of the second imaging optics. In this case, the optical axis of the first imaging optics should make a larger angle with the direction of the incident light than the optical axis of the second imaging optics. This angle should be from 70

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TO 90. The error receiver consists of at least two line-type photo-receiving devices, the defect signaling unit is located in the image plane parallel to the main receiver, and the defect detector is also parallel to it, but at a large distance to the main receiver. The defect signaling unit is separated from the main receiver by a remote zone. The scrap detector, with its edge directed towards the receiver, is in a position corresponding to the deviation of the image of the scanning line with an unacceptable depth of surface defects. At the output of the defect signaling unit, there is a logical OR cell for matching the signal of the defect area determining unit and the error signal. The width of the defect detector corresponds to the deviation of the image of the scanning line at the maximum expected depth of the defect on the surface of the test sample. The defect detector is located directly beside the defect signaling unit. Line-mounted photo-prong devices are made up of elongated photoelectric receiving elements made in rows.

It is advisable to make line-type photodetectors in the form of a slit diaphragm, next to it focusing optics and located in its plane of the image of the receiving element. The electronic processing circuits comprise a valve circuit that appears in the signal circuit after each output signal and the second input of which is associated with a width signaling circuit. Logic cells are respectively located at the output of the thickness and error processing units as a gate circuit. For signaling widths in the image plane of ONE of the imaging optics, there is a photoelectric width signal receiver receiving the image of the scanning line in each possible deflection position. This receiver of the signal spikes can also be located in the image plane of the beam path separated by the beam splitter. The width signal receiver and the imaging optics belonging thereto are in reflected diffused light inside the illumination of the beams, and the width signal receiver may consist of the imaging optics and the receiving element with a negligible coefficient of expansion.

The scanning beam of the illumination device is perpendicularly directed to the surface of the test sample. The specified illumination device can g-represent a point source of light in combination with a deflecting unit for stitching the light along the sample's scanning line.

The advantages of the invention are that with high measurement accuracy and performance in the process of testing samples, a number of data such as test sample lengths, thickness tolerance deviations, as well as surface defects such as cracks, holes, and holes are obtained without contact. others, and at the same time their sizes are determined by area, height and depth. Compared to other known solutions, the invention allows for very economical monitoring, since the processes are monitored simultaneously.

Figure 1 shows schematically the proposed device for counter 968376

l defects and geometric dimensions of the samples; Fig. 2 shows the same, and 1 control of geometric dimensions with two separately positioned reflecting optics; FIG. 3 shows a line photodetector with a slit diaphragm, focusing optics and a receiving element with a low coefficient of expansion.

O (option); figure 4 is a device, side view; Fig. 5 shows a receiver recording lateral surfaces in a quasi-parallel incidence of scattered light; Figure 6 shows the main receiver, one of the modifications; 7 is the same, modified modification; Figure 8 is the same as another modification; figure 9 is a photoelectric receiving device, modified,

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The device consists of a light source (not shown), a test specimen 1 with mechanisms 32 for transferring motion in the form of a roller bearing, reflecting optics 3 of a photoelectric receiving device 28, and electronic processing circuits 24. The splitter 10 and the receiver signals 11 may be missing.

0 The electronic processing circuitry system 24 consists of an error analysis block 25 and a thickness processing block 26. The error analysis block 25 consists of a block 20 for determining the area of a defect, a logical cell 29 OR, and a valve circuit 31; The Thickness Processing unit consists of two pulse formers 27 and a valve cxetibi 30. The device shows a non-contact test method for determining deviations of geometric dimensions and surface error, which can preferably be used in the case of flat or cylindrical test specimens 1 with a diffusely reflecting surface. Using a system of cylindrical lenses, a beam of rays (elements of the formation of the start of the rays not shown) is focused on the surface of sample 1 and forms a scanning line 2 or a focus is formed using rotation-symmetric imaging optics. The latter is deflected by a deflection unit, for example, a rotating mirror, a polyhedron, an electrical or acousto-optical deflecting element, along line 2 on the surface of test sample 1. As a source

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light, you can use a laser whose light is frequency-modulated with a modulation device. A scanning line 2 using imaging optics 3 in scattered light is imaged on a photoelectric receiving device 28 consisting of line-type photo-receiving devices. The latter are subdivided into a main receiver 5 for measuring the thickness of the test sample 1, as well as an error receiver comprising a defect signaling unit 17 and a reject detector 18. The main receiver 5 consists of the main 7 and secondary 8 receivers (in Figs 6-8, possible forms of the performance of the main receiver 5 are shown). The simplest version consists of a narrow main receiver 7 and a wider secondary receiver 8. It is assumed that the thickness tolerance varies only in one direction and therefore the image 4 of the scanning line 2 can also move only in one direction.

FIG. 7 and 8, the main receiver 7 is shown located between 1 and 2 secondary receivers B. This arrangement determines the thickness tolerance deviations in both directions. Fig. 8 shows a modification of the embodiment shown in Fig. 7, in which dead zones between the joints of the line-shaped φ of receiving devices, the main receiver 7 was installed in a different plane. The main receiver 7 is located in the image plane of the imaging optics 3 so that with the test sample 1 with a width corresponding to the tolerance, the image 4 of the scan line 2 is displayed on it. In this case, the secondary receiver 8 does not receive light from the image 4 of the scanning line 2. With the help of two pulse shapers, 27 pulses and a fan circuit 30, the input with negation of which is secondary. the receiver 8, the thickness processing unit 26 determines a single signal corresponding to a suitable signal. When the tolerance on the thickness of the test specimen i is exceeded, the image 4 or the SRI 2 sweep to the secondary receiver 8. If there is only 0

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to one minor r1c b, then it is assumed that the thickness tolerance can vary in one direction. The thickness processing unit 26 registers a defect signal for thickness. As shown in FIG. 2, it is possible to place the main 7 and secondary 8 receivers in the image planes of two separate display optics 12 and

13. It is advisable that a large angle be formed between the main receiver 7 with the optics belonging to it and the plane of the incident light, preferably in the range of 70

up to 90, since this results in a very narrow image 4 of the scan line 2 and provides improved resolution.

FIG. 3 shows that the line photodetector may consist of a slit diaphragm.

14, the focusing optics 15 and the receiving element 16 with a negligible coefficient of expansion. This modification is intended to measure thicknesses. Due to the presence of a slit diaphragm, the line-like character of the photodetector is retained. Focusing optics 15 serves to focus on the receiving element 16 of the luminous flux passing through the slit aperture 14. On this basis, this modification provides an assessment of the presence or absence of the image: neither 4 lines 2 sweep

in the appropriate place. The principle of determining the depth of surface defects. This is shown in FIG. 4. Using the imaging optics 3, the sweep line 2 is displayed on the main receiver 7, if the surface of the test sample has no errors. In the case of surface defects such as chips, holes, etc., the corresponding part of the image 4 of the scan line 2 goes away depending on the depth of the surface defect. and is located in the defect signaling block 17, or in the defect detector 18. The range of the defect signaling unit 17 is chosen so that it corresponds to the maximum care of the corresponding part of the image 4 of the scanning line 2 for the allowable depth of the surface defect. The reject detector 18, directly following the defect signaling unit 17, registers all defect depths exceeding a predetermined size and leading to an increase in rejects. Following the defect detector 8 and the defect signaling unit 17, the error analysis unit 25 immediately generates a defect signal when the light flux reaches the defect detector 18, which means that a defect is located on the surface of test sample 1, the depth of which exceeds the maximum allowable value. If there is a defect of a minor depth, then the corresponding light beams are directed only to the defect signaling unit 17. It is designed as a matrix device with a charge connection and is electrically connected to the area determining unit 20. The latter determines the area of the defect due to the unit elements of the matrix devices with charge coupling subjected to illumination. If this area in combination with the depth of the defect exceeds a predetermined value, then a reject signal is generated. It is also possible to detect the location of a defect by determining one or several single elements of a matrix device with a charge coupling subjected to illumination. Deep defects, such as cracks, deep holes, and the like, in which the image on the photoelectric receiving device 28 does not appear due to shadowing of the defect edges, are recorded as interrupting the image 4 scan lines 2 and are detected as the corresponding defect using block 25 error analysis. If one defect signaling block I7 and one defect detector 18 are placed on both sides of the main receiver 5, it is also possible to estimate the location of the first hole and the surface peaks of the test sample, since the image 4 of the scanning line 2 can move on both sides in the main direction receiver 7. In order to avoid obtaining photosensitive zones at the joints between the individual line-like photodetectors, it is also possible to place them in two planes located close to each other so that s are string boxes. photodetectors overlap. Figure 9 presents a possible modification of the photoelectric receiving device. AT

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96837I

In case of inaccurate positioning or different lengths of the test sample 1, it is necessary to equip the processing units 25 and 26 of the electronic circuit 24 with the initial and final signals, the control valve circuits 30 and 31, so that the defect signal does indicate the defect, and not the beginning or end of the test sample 1 In the embodiment shown in FIG. The beam splitter 10 reflected in the beam reflects part of the light to the receiver 1 of width signals, which supplies the corresponding initial and final signals. In combination with the valve circuits 30 and 31 at the output of the error analysis block 25 and the thickness block 26, these signals result in processing only the light reflected by the test sample 1.

The expedient performance of the receiver 11 signals width presented in figure 5. The beam splitter 21, focusing optics 22 and receiving element 25–23 are placed in the course of rays of light scattered quasi-parallel to the scanning beam. Due to this, shading of scattered light by surface defects is almost completely prevented. Relative to the area, the width signal receiver 11 is constructed in such a way that the overall image 4 of the scanning line 2 is displayed on it regardless of whether the scanning line 2 deviates or not. In addition, it is possible to use a signal received from the width signal receiver 11 to control the intensity of the lighting device.

When using modulated light, such as laser light, in combination with a deflecting unit, all line-type photo-reception devices are made as separate elements. Based on the fact that line 2 of the sweep and, therefore, in this case also, its image 4 consists of successive light points that appear, it is possible to calculate information on the area and location of the defect and on the receiver 11 signals by counting the light points of the pulses of the defect detector 18 width - about the beginning and the end, as well as about the length of the test sample 1; In order to determine the area and location of the defect, it is more expedient to use not only

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impulses of defect detector 18, but also distorted pulses of the main receiver 5, especially the main receiver 7, because they allow 1296837

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These data will be determined more accurately, regardless of the depth of the defect and the width of the sweep line 2.

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Editor S. Lisin

Compiled by E.Glazkova Tehred A. Kravchuk

Order 764/41 Circulation 678 Subscription

VNIIPI USSR State Committee for Inventions and Discoveries 4/5, Moscow, Zh-35, Raushsk nab. 113035

Production and printing company, Uzhgorod, st. Project, 4

Proofreader G. Reshetnik

Claims (24)

1. DEVICE FOR CONTROL OF GEOMETRIC DIMENSIONS AND DEFECTS OF SAMPLES WITH DIFFERENT SURFACES, containing a lighting device for optical scanning of the test sample in rows, a mechanism for transmitting movement of the test sample relative to the scan line, approximately perpendicular to the scanning line, as well as electronic circuit and - of course, with the fact that, in scattered light, at least one imaging optics is located and in its image plane a photoelectric receiver, extending along the image of the scan line and consisting of a collapsible main receiver that accepts the display of the scan line in its nominal position and an error receiver, the main receiver containing several line-shaped photodetectors and at least two photodetectors in the thickness processing unit in the electronic data processing circuitry connected to control the thickness while the error receiver is connected to the electronic unit for error handling. 2. The device according to claim 1, characterized in that as the main receiver, two line-shaped photodetectors are used, consisting of a main receiver and a secondary receiver installed in the main part of the radiation, which are located next to each other. 3. The device according to claim 1, characterized in that three line-shaped photodetectors are used as the main receiver, consisting of a middle main receiver installed in the main part of the radiation and two electrically secondary e receivers connected * to each other, which are located ~ one next to the other. 4. The device according to π.Ι, which means that the first line-shaped photodetector with a slit extending along the line length and immediately behind this slot is a second line-shaped photodetector, the second line-shaped photodetector is the main receiver installed in the main part of the light flux, and the first line-shaped photodetector serves as a secondary receiver. 5. The device according to paragraphs. 2 and 4, characterized in that the main receiver is located directly in front of the neck of the first line-shaped photodetector. 6. The device according to paragraphs. 2-4, about t SU „1296837 characterized in that the separate secondary receivers located on both sides of the main receiver are respectively connected to a separate analysis scheme for observing the thickness tolerance in the electronic data processing circuit. 7. The device according to claims 2-6, characterized in that the line-shaped photodetectors are located in the image plane of the same imaging optics. 8. The device according to claims 2-6, characterized in that the main receiver is located in the image plane of the first display optics, and secondary receivers are located in the image plane of the second display optics. 9. The device according to claim 8, characterized in that the optical axis of the first imaging optics is a greater angle with incident light than the optical axis of the second imaging optics. 10. The device according to claim 9, wherein the angle between the optical axis of the first imaging optics and the geometric standard of the surface of the test sample is formed in the range from 70 to 9 (7 ’. 11. A device according to π.1, characterized in that the error receiver consists of at least two line-shaped photodetectors, one of which is a defect signaling unit and the other is a defect detector, and the defect signaling unit is located in the image plane parallel to the main receiver , and the defect detector is also parallel to the main receiver, but at a greater distance from it. 12. Device pop. 11, which means that the defect alarm unit, separated by a remote zone, follows the main receiver and the defect detector with its edge directed towards the main receiver is in the position corresponding to the deviation of the scan line image at unacceptable depth of defects = surface, and at the output of the defect signaling unit in the error analysis unit, a defect area determination unit for receiving an error signal and an OR logical cell connected to the defect detector are introduced. 13. The device according to p. 12, characterized in that at the maximum expected depth of the defect in the surface of the sample, the range of the defect detector corresponds to the deviation of the image of the scan line. 14. The device according to PP.11 and 13, characterized in that the defect detector is located directly at the defect alarm unit. 15. The device according to PP.2-14, characterized in that as the line-shaped photodetectors are used elongated photoelectric receiving elements made in the form of strings. 16. The device according to claims 2-14, characterized in that a slit diaphragm is used as line-type photodetectors, focusing optics are next to it and in its image plane is a receiving element with a slight expansion coefficient. 17. The device according to claims 1-16, characterized in that a width signal receiver is connected to it, connected to the gate circuits of the output electronic circuit block located in the signal circuit. 18. The device according to 17, characterized in that, as the valve circuit at the output of the thickness processing unit and the error analysis unit, correspondingly located ones are used; separate logical cells I. 19. The device according to PP.17 and 18, characterized in that as a receiver of the width signals in the image plane of one of the display optics, a photoelectric receiver of the width signals is used to display the scan line in each possible deviation. 20. The device] according to claim 1, wherein the beam splitter is placed in front of the photoelectric receiving device, and the width signal receiver is placed in the image plane of the separated beam path behind the beam splitter. 21. The device according to claims 1 and 20, characterized in that the imaging optics and the receiver of the width signals are located in its plane in the scattered light inside the path of the rays in the lighting system, 22. The device according to claims 19-21, characterized in that the width signal receiver consists of imaging optics for the width signal element and a receiving element located in its image plane with a slight expansion coefficient. 23. The device according to claims 1 to 22, characterized in that the scanning beam of the lighting device is directed perpendicular to the surface of the test sample. 24. The device according to claims 1 to 23, characterized in that as a lighting device. a light source for point radiation and a deflecting unit are used to deflect the light beam in rows along the scan line of the test sample.