JPH02168105A - Inspecting method of shape of workpiece - Google Patents

Abstract

PURPOSE:To enable accurate, highly-precise and quick inspection o f the whole shape of a workpiece by a method wherein a flash light is applied to the workpiece in conveyance and an image of the peripheral edge part of the workpiece is projected on a base in a camera and collated with a reference image. CONSTITUTION:Cameras 5 are provided inside with a base 4 having a number of elements arranged longitudinally and laterally and a lens 6, and flashes 7, are disposed oppositely in a plurality above and below a conveyance system 3 respectively, constituting a shape inspecting element 8, so that they are aligned to the peripheral end face of a workpiece 2 being conveyed, at prescribed positions of the conveyance system 3 constructed of a chain conveyor having a feed pawl 1, and others. The base 4 in each camera 5 is connected to an image detecting device 10, and a partial image of the workpiece 2 projected on each base 4 is displayed and subjected to analysis and computation to prepare an image information. The image informations thus prepared are joined mutually in an arithmetic device 11 of a controller subsequently and subjected to analysis and computation therein, so as to detect the whole shape of the workpiece 2.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for inspecting the shape of a workpiece. More specifically, the present invention relates to a method for inspecting the shape of a workpiece, which allows the entire shape of the workpiece to be inspected accurately, with high precision, and quickly.

(Prior art) Conventionally, a shape inspection section for inspecting the shape of a workpiece is installed at a predetermined position in a workpiece conveyance system such as a plate, and the acceptability of the workpiece is determined based on the difference from the product standard value. Things are being done. For inspecting the shape of such workpieces, for example, as shown in Figure 8, a pair of phototubes on the left and right are installed at a predetermined position on a conveyor system (2), which is equipped with a chain conveyor (A) and a feed pawl (B). A method is known in which a shape inspection section (e) is provided in which sensors (1) such as the above are arranged facing each other, and the shape of a workpiece (force) such as a plate passing through the section is inspected.

FIG. 9 shows an inspection example of the workpiece shape inspection method shown in FIG. 8.

When the workpiece (force) with one end in contact with the feed claw (a) is conveyed to the shape inspection section (e), each sensor (workpiece) detects the end of the workpiece (force). Calculate the time difference (s) in which each sensor (1) detects the end of the workpiece (force),
Determine whether the shape of the workpiece (force) is a predetermined shape.

Further, as a method for inspecting the shape of a workpiece of a minute product such as a semiconductor chip with a degree of opening of 1, attempts have been made to use a group of devices as shown in FIG. 10, for example.

In other words, a shape inspection section (e) is provided with a camera (ri) having a substrate (i) having a large number of elements therein and a flash (ge) facing it, respectively, installed above and below the conveyance system (i).
When the workpiece (force) is sent to this shape inspection section (O), the workpiece (force) is irradiated with a flash of light from the flash (ge), and this irradiated light is passed through the lens (c) in the camera (ri) to the substrate (cute). ) to form a projected image of the workpiece (force) on the substrate (g). This board (x) is connected to an image detecting device (su), and the image detecting device (su) displays an image (xi) as shown in the dotted circle. At this time, the horizontal and vertical lines displayed on the image (C) are the lines that cross the board (
G) is the element line (S), and what is displayed as a shadow is the projected image (C) of the workpiece (force). Image detection detects the number of element lines (S) in this projected image (C). Measurements and calculations are made using the analysis and calculation equipment installed in the equipment. This measurement result is checked and compared with the product standard value to determine whether the workpiece (force) is acceptable or not. In this case, defective holes are also detected.

(Problems to be Solved by the Invention) However, in reality, there are still many problems to be solved in such conventional workpiece shape inspection methods.

In the methods illustrated in FIGS. 8 and 9, depending on the conveyance state, the workpiece (force) may be conveyed separated from the feed claw (A), as shown in FIG. 11, for example. . In such a state, even if the workpiece (force) passes the product standard value, the values detected by each sensor (workpiece) will be significantly different, and the workpiece will be recognized as a defective product. For this reason, it becomes impossible to accurately inspect the shape of the workpiece (force). In order to perform accurate inspection, it is necessary to temporarily stop the conveyance system and bring one end of the workpiece (force) into contact with the feed claw (a) again, making this maintenance work extremely troublesome. The work efficiency of shape inspection is also significantly reduced. In addition, the detection accuracy of sensor (1) is
In reality, it is impossible to inspect the shape of the workpiece (force) with high precision because it is not constant with respect to the conveyance speed.Furthermore, in this conventional example, the shape inspection section (E) Since the sensor (1) faces left and right to the workpiece (force), it can only measure and inspect the shape of the front end surface with respect to the horizontal end surface of the workpiece (force), that is, the surface angle of the workpiece (force). There was also the problem that it was not possible to grasp the overall shape of (force).

On the other hand, in the shape inspection method shown in FIG.
The disadvantage is that unless the force is in the field of view of the camera, its shape cannot be inspected. In order to solve this problem, it is possible to expand the field of view of the camera (ri), but
Since it is extremely difficult to miniaturize a camera, a conventional substrate with a certain range of element wires is used.
When the field of view is expanded, the precision of one element of the image (b) decreases. For this reason, for example, a workpiece such as a plate can be
It was impossible to test using the method illustrated in Figure 0.

This invention was made in view of the above circumstances,
The present invention aims to eliminate the drawbacks of conventional workpiece shape inspection methods and to provide a workpiece shape inspection method that can accurately, highly accurately, and quickly inspect the entire shape of a workpiece.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a camera and a flash, which are equipped with a board having a large number of elements in the vertical and horizontal directions at the top and bottom of predetermined positions on the peripheral edge of the workpiece. A method for inspecting the shape of a workpiece, which comprises arranging a plurality of the workpieces facing each other, irradiating the workpiece with a flash of light during transport, and projecting an image of the circumferential edge of the workpiece onto a substrate in a camera, which is then compared with a reference image. provide.

In this shape inspection method, at least one camera and a flash are arranged facing each other at corresponding positions on the right and left and/or front and rear ends of the workpiece in the direction of workpiece conveyance to determine the length of the workpiece and/or measure the width,
Can be inspected.

Furthermore, at least two or more cameras and flashes are placed facing each other at corresponding positions on the vertical and horizontal ends of the workpiece to inspect the surface angle of the workpiece.

Furthermore, the straightness of the workpiece is inspected by disposing at least three or more cameras and flashes facing each other at corresponding positions on one or both of the vertical and horizontal ends of the workpiece.

In any of the above-described workpiece shape inspection methods of the present invention, a camera and a flash are arranged facing each other at the peripheral edge of the workpiece, and a separate camera and a half-mirror optical system and a separate camera By installing this, the shape of the workpiece can be inspected with higher precision.

(Function) In the present invention, a plurality of cameras each having a substrate having a large number of elements in the vertical and horizontal directions and a plurality of flashes facing the cameras are arranged vertically at corresponding positions on the circumferential edge of the workpiece. The image is projected onto the board inside each camera and compared with the reference image, making it possible to accurately measure and inspect the overall shape of the workpiece. By combining the image information of partial images of the workpiece with each other in the controller calculation unit, converting the state, analyzing and calculating, the shape of the entire workpiece can be accurately detected without being affected by the transport state of the workpiece. can do.

Furthermore, by using a half-mirror and full-mirror optical system, inspection can be performed with higher precision.

(Example) Hereinafter, an example will be shown along with the drawings, and the workpiece shape inspection method of the present invention will be explained in more detail.

FIG. 1 is a cross-sectional view showing a second example of the method for inspecting the shape of a workpiece according to the present invention.

At a predetermined position in the conveyance system (3) for the workpiece (2) consisting of a chain conveyor or the like having a feed claw (1), on the circumferential end surface of the workpiece (2) to be conveyed (in the case of Fig. 1, on the front and rear end surfaces). ,
A plurality of cameras (5) each having a substrate (4) having a large number of elements in the vertical and horizontal directions, a camera (5) equipped with a lens (6) inside, and a plurality of flashes (7) are arranged facing each other above and below the transport system (3). ing. This constitutes a shape inspection section (8). In the shape inspection section (8) shown in FIG.
) and at the same time enter the field of view of the start sensor (9).
The flash (7) is caused to emit light by the signal.

The board (4) in each camera (5) is connected to the image detection device (1).
0) and this image detection device! In (10), the partial image of the workpiece (2) projected onto each substrate (4) is displayed, and the image information is analyzed and calculated to create image information.
), and analyze and calculate the workpiece (
2) Detect the overall shape. Information on the overall shape of the workpiece (2) is further sent to the terminal (12), and the information on the overall shape of the workpiece (2) is sent to the terminal (12).
) is used for production control.

In the method for inspecting the shape of the workpiece (2) having such a configuration, the shape inspection section (8) irradiates the irradiation light of the workpiece (2) onto the substrate (4) in the camera (5) through the lens (6). ) to form a partial image of the workpiece (2) on the substrate (4). An example of the partial image is the diagonal line in the 0 image (13) within the dotted line circle in Figure 1. The part indicated by is the workpiece (
The arrow (A), which is the partial image (14) of 2), indicates the direction of movement of the workpiece. Further, a reference line (15) is displayed on the image (13) as a reference for inspection. The reference line (15) indicates the position of the end of the standard product of the work (2). Of course, image (13) also includes
Although not shown, element lines similar to those in the conventional example shown in FIG. 10 are also displayed. This element line is, for example, 128
256 elements are drawn horizontally.

Assuming that image (13) is 1112Iw11 and 10 cities wide, the unit length per element is 2
ram/12g element=0.016m+, width 10m
+/256 elements=0.04mo. In this example within the dotted circle, the difference between the reference line (15) and the partial image (14) of the workpiece (2) is indicated by a vertical arrow. Assuming that this difference is 10 elements on average, workpiece (2)
is 0.016 +u+ X from this reference line (15)
It is confirmed that there is a deviation of 10 elements=0.16+m+.

Measurement of the average number of elements and conversion of the deviation of the portion (JA (14)) from the reference line (15) to an actual length are all automatically performed by the image detection device (10).

Note that the vertical and horizontal lengths of the image 1fi (13) are not particularly limited and can be set to appropriate lengths by adjusting the distance between the substrate (4) in the camera (5) and the lens (6). .

FIG. 2 shows an example of measuring and inspecting the width of a workpiece using the workpiece shape inspection method of the present invention.

In this example, cameras (5a>(
5b) are arranged facing each other. Camera (5a) board (4
FIG. 2(b) shows a partial image of the workpiece (2) projected onto the image of the camera (5b).
FIG. 2(c) shows a partial image of the workpiece (2) projected onto the workpiece 4b).

As shown in FIG. 2(b), the image (13a) includes a reference line (15a) and a partial image (14) of the workpiece (2).
a> is displayed. In this example, the partial image (1
4a) is the image <13a) by α from the reference line (15a)
It is shifted downward. Further, as shown in FIG. 2(C), a reference line (15b) and a partial image (14b) of the workpiece (2) are displayed in the image (13b).

In this example, the partial image (14b) is based on the reference line (15
It is shifted downward from picture a (13b) by β from b).

As described above, after this deviation is analyzed and calculated by the image detection device, the width (X) of the workpiece (2) is measured by the controller calculation device.

In this controller calculation device, the reference line (15a) (1
5b) Even if the mutual length (W) is input as the product standard value, and x=W-(α-β) is input as the formula for calculating the width (x) of workpiece (2), The width (x) of the workpiece (2) is automatically calculated using the information about α and β from the 0-image detection device and this formula. In this way, the width (x) of the workpiece (2) can be accurately measured, and a pass/fail judgment can be made by comparing it with the reference line. In addition, as shown in FIG.
By arranging the workpiece (2) in a positional relationship that faces the workpiece (2) back and forth, the length of the workpiece (2) can be measured and inspected.

In this way, the length or width of the workpiece (2) is determined in the transport direction (
For A), by arranging at least 61 cameras in opposing positions on the left and right or front and back, it becomes possible to measure and inspect the camera. Also, work (2)
Even if it is separated and conveyed by the feed claw, it can be corrected using the above calculation formula, and the accuracy of measurement and inspection is significantly improved.

FIG. 3 shows an example of inspecting the squareness of a workpiece by the method of the present invention.

In this example, as shown in FIG. 3(a), two cameras (5
3a> (53b), two cameras (53c) (53d) are placed at corresponding positions on the lateral end, and a board (43a) is installed inside each camera.
) (43b) and the reference lines of the substrates (43c) and (43d) are orthogonal to each other.

FIG. 3(b) shows the state when the workpiece (2) is separated from the feed claw of the transport system (3) and is transported, and the state is shown by each camera (53a>(53b)(53c)(53d). ) captured by (i (133a) (133b) (133c
) (133d).

In this case, first, the controller calculation bag! In the image (133a) (133b), the reference line (153a) (
153b) and the partial image (143a
0
Reference line (153c) of image (133c) (133d)
) (153d) and the extension line (16).
) are in a perpendicular relationship, so by shifting the angle (θ1) from the extension line (18), the straight line (19) in a positional relationship perpendicular to the extension line (17) is imaged as shown in Figure 3(c). Draw a line on the display of the detection device.

Next, in this image detection device, the workpiece (2) of the straight line (19) and the partial images (143c) (143d)
The element line between the region (21) and the extension line (20) connecting the end line corresponding to the end face of is measured, and the squareness of the workpiece (2) is calculated.

In this way, even when the workpiece (2) is detached from the feed claw and transported, the squareness of the workpiece (2), which cannot be inspected using conventional methods, can be accurately inspected. As in the past, the conveyance system (3) is stopped and the workpiece (2) is
) Since there is no need to perform maintenance work to correct the condition, the work efficiency of shape inspection is significantly improved.

Also, for the perpendicularity of the workpiece (2), it is sufficient to install at least four cameras, two at corresponding positions on the vertical edge of the workpiece and two at corresponding positions on the horizontal edge. , the number can be increased depending on the shape and size of the workpiece.

FIG. 4 shows an example of testing linearity using the method of the present invention.

In this example, three cameras (54a) (54b) (54c) are placed above the JA line end of the workpiece (2). Each of these cameras (54a) (54b) (
Image (134a) (134bH13) captured by
4c) and workpiece (2) together are shown in FIG. 4(b), which is a partial molecule of workpiece (2) in the 0 image inspection apparatus! (144a) and (144C) are subjected to image analysis and calculations similar to those shown in FIG. 22). This straight line (22) is displayed on the image (134b) and the partial image (14
4b), the end line and straight line (2) corresponding to the end face of the workpiece (2)
The linearity of the workpiece (2) is calculated by measuring the number of element lines existing in the area between the workpiece (2) and the workpiece (2). The straightness of not only the lateral end surface but also the M end portion can be inspected using a method similar to the method described above. Straightness can be measured using at least three cameras.

FIG. 5 shows an example of the configuration of a camera arranged to inspect the length, width, squareness, and straightness of a workpiece according to the workpiece shape inspection method of the present invention.

As in this example, by arranging at least three cameras (5) at corresponding upper positions of each end of the workpiece (2), that is, 12 cameras in total, the cameras (5) can be used to measure the length and width of the workpiece (2). , squareness and straightness can be inspected. In addition, in this case, cameras (
5) board <45a) and the boards located on the left and right (45b)
are arranged so that the reference lines within the substrate are perpendicular to each other.

Furthermore, in order to inspect the corner part (B) of the workpiece (2) illustrated in FIG.
Cameras can also be placed.

However, as explained with reference to Fig. 1, the number of elements drawn on the board inside the camera is different depending on the length and breadth of the board, and the length and breadth of the board itself are also different, so the unit length per element is It is common for the height and width to rise. A camera equipped with such a board is used as a workpiece (
When placed at the corner part CB) of 2), the partial image of the fine workpiece (2) in the direction of the element line, where the unit length per element is short, is displayed accurately on the image detection device, but the unit length per element is The detection accuracy of a partial image of the workpiece (2) in the rough element line direction where the unit length is longer than this is lower than this.Due to this difference in accuracy, it is possible to detect a partial image of the workpiece (2) with high precision.
It becomes impossible to inspect the shape of a part of the corner (B). Therefore, so that the number of elements on the corner part (B) next to the fir tree is the same,
It is possible to arrange two cameras with the board directions perpendicular to each other, but in reality the two cameras are placed in a part of the corner (B
) is impossible due to the physical constraint that the cameras overlap each other.

In order to overcome these drawbacks, in this invention,
As illustrated in Fig. 6, a part of the corner of the workpiece (2)
In B), one camera (56a) and a flash (7) facing it are placed above and below the conveyance system of the workpiece (2), and at the same time, a half mirror (23) and a full mirror (24) are placed. Then, a camera <56b) is placed at a position where the reflected light from all the mirrors (24) is incident. Moreover, in this case,
Boards (46a) (46) inside cameras (56a) (56b)
b) are arranged so that the directions are perpendicular to each other so that the corner part (B) of the workpiece (2) can be detected with the same accuracy from two directions.

In this case, when the workpiece (2) is irradiated with flash light from the flash (7), a part of the irradiated light is transmitted to the half mirror (23).
) to the camera <56a. Further, a part of the irradiated light is reflected on the surface of the half mirror (23), reaches the full mirror (24), and is reflected there again to enter another camera (56b). This allows the work (
A part of the corner (B) of 2) is covered with two cameras (56a) (5
6b), and the partial images of the workpiece (2nd) have the same accuracy.

These image information are mutually combined in the image detection device and the controller detection device, and are analyzed and calculated to inspect the shape of the corner part (B) of the workpiece (2).

Furthermore, by using this half-mirror and full-mirror optical system, the camera (5) can be
can be arranged at a high density near the circumferential end surface of the workpiece (2), which allows for even higher precision workpieces (
2) shape inspection becomes possible.

Of course, this invention is not limited to the above examples;
Number of camera and board elements, camera 1. half mirror
It goes without saying that various aspects are possible with respect to details such as the arrangement positions of all the mirrors.

(Effects of the Invention) According to the workpiece shape inspection method of the present invention, the entire shape of the workpiece can be accurately inspected.

Further, the shape of a workpiece that is transported away from the feed claw can also be accurately inspected. Therefore, the shape of the workpiece can be continuously inspected without stopping the conveyance system, and a highly efficient shape inspection method can be realized.

By using an image processing device and a controller arithmetic device, the accuracy of the shape inspection is significantly improved, and it is possible to accurately determine whether or not the workpiece is acceptable or not.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing an example of the workpiece shape inspection method of the present invention. FIG. 2 is a plan view showing an example of width and length inspection by the workpiece shape inspection method of the present invention. FIG. 3 is a plan view showing an example of squareness inspection by the workpiece shape inspection method of the present invention. FIG. 4 is a plan view showing an example of straightness inspection by the workpiece shape inspection method of the present invention. FIG. 5 shows the width according to the workpiece shape inspection method of the present invention.
FIG. 3 is a plan view showing the position of a camera for inspecting length, squareness, and straightness. FIG. 6 is a side view showing an example of inspection of a part of a corner by the workpiece shape inspection method of the present invention. FIG. 7 is a partial plan view showing another example of the arrangement position of the camera in the workpiece shape inspection method of the present invention. FIG. 8 and FIG. 9 are plan views each showing a conventional workpiece shape inspection method. FIG. 10 is a side sectional view showing another conventional method of inspecting the shape of a workpiece. FIG. 11 is a plan view showing one state in a conventional shape inspection method. 1...Feeding claw 2...Word 3...Transport system 4...Substrate 5...Camera 6...Sensor 7...Flash 8...Shape Inspection section 9...Start sensor 10...Image detection device 11...Controller calculation device 12...Terminal 13...Image 14...Workpiece partial image 15...Reference line 16.17, 18.20... Extension line 19.22... Straight line 21... Area 23... Half mirror - 24... Full mirror -

Claims (5)

[Claims] (1) A plurality of cameras and flashes each equipped with a substrate having a large number of elements vertically and horizontally are arranged facing each other at the top and bottom of a predetermined position on the peripheral edge of the workpiece, and when the workpiece is transported, the flashlight is irradiated onto the workpiece. A workpiece shape inspection method characterized by projecting a circumferential edge image onto a substrate within a camera and comparing it with a reference image. (2) A claim in which the length and/or width of the workpiece is inspected by arranging at least one camera and a flash facing each other at corresponding positions on the left and right and/or front and back ends of the workpiece in the workpiece transport direction. (1) Inspection method for workpiece shape as described. (3) The method for inspecting the shape of a workpiece according to claim (1), wherein the squareness of the workpiece is inspected by arranging at least two or more cameras and flashes facing each other at corresponding positions in the vertical and horizontal ends of the workpiece. (4) The workpiece shape according to claim (1), wherein the straightness of the workpiece is inspected by disposing at least three or more cameras and flashes facing each other at corresponding positions on one or both of the vertical and horizontal ends of the workpiece. Inspection method. (5) The workpiece according to claim (1), wherein a camera and a flash are disposed facing each other at the peripheral edge of the workpiece, and a half-mirror and full-mirror optical system and another camera are installed to inspect the shape of the workpiece with high precision. Shape inspection method.