JPH07167629A - Measuring method of interval of arrangement of pin-shaped article - Google Patents

Abstract

PURPOSE:To measure intervals of the arrangement of terminals simply and accurately. CONSTITUTION:Electronic parts 1 have a plurality of mutually approximately parallel terminals 2, and the front end sections of each terminal 2 are tapered. A TV camera 3 has an optical axis approximately parallel with the direction of the projection of the terminals 2, and image-senses the terminals 2 from the front end sides of the terminals 2. Each terminal 2 is inserted into the through-holes 5 of an auxiliary jig 4, in which an opposed surface with the TV camera 3 is formed in a white diffuse reflection surface, respectively. The surface of the auxiliary jig 4 is irradiated with light from the oblique direction by a luminaire 6. Consequently, the surface of the auxiliary jig 4 lightens, and the front end sections of the terminals 2 are also irradiated with diffusive light from the surface of the auxiliary jig 2 and lighten. On the other hand, light does not reach into the through-holes 5, and the through-holes 5 lighten. Accordingly, dark regions are acquired around light regions corresponding to the terminals 2 by the TV camera 3, and density is binarized, thus easily detecting the places of the terminals 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention takes a picture of a plurality of pin-shaped objects arranged substantially parallel to each other, and obtains the pin-shaped object arrangement interval based on the brightness of each part of the picked-up image. The present invention relates to a method for measuring arrangement intervals of objects.

[0002]

2. Description of the Related Art In general, electronic parts such as FETs are provided with a plurality of terminals in the form of pins, and when these electronic parts are mounted on a printed wiring board, they are mounted on the printed wiring board. It is necessary to insert each terminal correctly in the formed hole. Therefore, it is necessary to measure the arrangement interval of the terminals in the electronic component in advance to determine whether or not it matches the interval of the holes formed in the printed wiring board.

In order to meet such a requirement, conventionally, as shown in FIG. 8, two Ts having an optical axis substantially orthogonal to the projecting direction of the terminal 2 and having different optical axis directions from each other.
The terminals 2 and the fixing pin 18 of the electronic component 1 are imaged using the V cameras 3a and 3b, and image processing is performed on the images obtained by the TV cameras 3a and 3b. A method of obtaining the arrangement interval has been proposed. In this method, planar illumination devices 6a and 6b are arranged so as to face the TV cameras 3a and 3b with the terminal 2 and the fixing pin 18 interposed therebetween, and the silhouettes of the terminal 2 and the fixing pin 18 are set to the TV camera 3a and the fixing pin 18, respectively. By imaging with 3b, the terminal 2 and the fixed pin 18 are distinguished from the background. Here, in the example shown in FIG. 8, a pair of FETs each having three terminals 2 is attached to a heat sink having two fixing pins 18 to form an electronic component 1.

On the other hand, as shown in FIG. 9, a method of measuring the distance to each terminal 2 using a laser displacement meter 20 has also been proposed. The laser displacement meter 20 includes a terminal 2 and a fixing pin 18.
The laser beam is projected onto the terminal 2 and the fixing pin 18
Of the specularly reflected light at the terminal 2, or the interference between the reference light that has passed through the known optical path and the specularly reflected light at the terminal 2 or the fixed pin 18. Is used to obtain the optical path length.

[0005]

If the TV cameras 3a and 3b are used, the TV cameras 3a and 3b are
For example, images as shown in FIGS. 10A and 10B are obtained. Now, assuming that the electronic component 1 is provided with six terminals 2 and two fixing pins 18, the four terminals 2 are aligned substantially in the optical axis direction of the TV camera 3b, and the remaining terminals are It is assumed that the two terminals 2 and the two fixing pins 18 are aligned substantially in the optical axis direction of the TV camera 3b. In this case, the TV camera 3a is shown in FIG.
Even if all the six terminals 2 and the two fixing pins 18 are imaged as shown in FIG.
As described above, the terminals 2 and the fixed pins 18 are overlapped and imaged, so that only three are visible. That is, when the terminal 2 and the fixed pin 18 are imaged in an overlapping manner, there is a problem that it is not possible to determine whether the terminal 2 and the fixed pin 18 which are closest to the TV camera 3b and the terminal 2 and the fixed pin 18 which are hidden behind the fixed pin 18 are good or bad. Will occur.

In order to solve such a problem, three or more TV cameras whose optical axes are different from each other are used and the terminal 2 is used.
And the fixed pin 18 are imaged, or the electronic component 1 and the TV camera 3 are relatively rotated using one TV camera to image the terminal 2 and the fixed pin 18 from three or more different directions. However, it is not practical because the image processing becomes complicated.

When the laser displacement meter 20 is used, no problem will occur if the surface of the terminal 2 is smooth, as shown in FIG. 11A, but the laser beam as shown in FIG. 11B is used. If the foreign matter 21 adheres to the area irradiated with, the laser light will not be normally reflected and the distance cannot be measured. Further, even when the laser displacement meter 20 is used, when the terminals 2 are overlapped, each terminal 2
It is impossible to measure the distance for each.

An object of the present invention is to solve the above-mentioned problems. By picking up an image of a pin-shaped object from the tip side, all pin-shaped objects can be picked up without overlapping, and each pin-shaped object can be picked up. By providing an illumination method in which objects are clearly distinguished from the background, an object of the present invention is to provide a method for measuring the spacing between pin-shaped objects, which enables the spacing between pin-shaped objects to be determined easily and accurately. It is a thing.

[0009]

According to the present invention, in order to achieve the above object, a plurality of pin-shaped objects which are arranged substantially parallel to each other and whose tip portions are tapered are formed substantially in the longitudinal direction of the pin-shaped objects. An area including the tips of a plurality of pin-shaped objects is imaged by a two-dimensional imaging device having coincident optical axes, and the position of each pin-shaped object is detected based on the brightness of each part of the captured image. In the pin-shaped object arrangement interval measuring method for determining the object-shaped object arrangement interval, a plurality of through-holes having an opening area slightly larger than the cross section orthogonal to the longitudinal direction of each pin-shaped object are made to correspond to each pin-shaped object. Using the auxiliary jig formed on the auxiliary jig, insert each pin-shaped object into each through hole of the auxiliary jig so that the tip of the pin-shaped object protrudes toward the imaging device side with respect to the auxiliary jig. The pin-shaped object from one side that is the tip side of the pin-shaped object Over the circumference and then irradiating the light diffusible.

[0010]

According to the above structure, since the pin-shaped objects are imaged from the tip side by the two-dimensional imaging device, the pin-shaped objects do not overlap each other in the visual field of the imaging device, and as a result, the arrangement interval is increased. The pin-shaped objects to be obtained are located at different parts in the image. In addition, since each pin-shaped object is inserted through the through hole provided in the auxiliary jig, a diffused light beam is emitted from one surface of the auxiliary jig over the entire circumference of the tip of the pin-shaped object. As a result, the surface of the auxiliary jig and the tip of the pin-shaped object can be made brighter than the inside of the through hole of the auxiliary jig. That is, if the pin-shaped objects are substantially parallel, the position of the pin-shaped objects can be detected only by capturing an image from one direction regardless of how they are arranged.
The arrangement interval of the pin-shaped objects can be accurately and easily obtained. In particular, in the related art, the imaging time is required from two or more directions, and the processing time is long, but the processing time is shortened because one imaging is required (for example, about 50 msec). It will be.

[0011]

【Example】

(Embodiment 1) In each of the following embodiments, an example is shown in which the pin-shaped object is a terminal of an electronic component such as an FET used in an inverter circuit for lighting a discharge lamp. That is, as shown in FIG. 1, the electronic component 1 is provided with three terminals 2 protruding, and the intervals and positions of these terminals 2 are detected by image processing technology. Here, the tip of each terminal 2 is formed to be tapered.

The terminal 2 of the electronic component 1 is imaged by the TV camera 3 as an image pickup device. The TV camera 3 has an optical axis substantially parallel to the protruding direction of the terminal 2 of the electronic component 1, and the TV The camera 3 captures an image of the tip of the terminal 2. Further, in front of the TV camera 3, an auxiliary jig 4 having a diffusing surface (matte coating) such as a white surface facing the TV camera 3 is arranged. Has a plurality of through holes 5 through which the terminals 2 are respectively inserted. That is, the optical axis direction of the TV camera 3 substantially coincides with the normal direction of the surface of the auxiliary jig 4, and each terminal 2 projects through the through hole 5 to the surface of the auxiliary jig 4 facing the TV camera 3. In the TV camera 3, only the tip of the terminal 2 is imaged. Here, each through hole 5 is formed to have a diameter slightly larger than that of the terminal 2, and the distance between the through holes 5 is set to match the desired distance between the terminals 2. That is, the diameter of the through hole 5 is set with a margin with respect to the tolerance of the diameter and the pitch of the terminal 2, and is set to, for example, 3 mm with the tolerance of the diameter of the terminal 2 being 1.4 mm. However, if the diameter of the through hole 5 is made too large, it will not be possible to make a determination as will be described later. Further, the thickness of the auxiliary jig 4 may be set smaller than the minimum allowable dimension of the terminal 2 so that the tip of the terminal 2 projects. For example, the minimum allowable dimension of terminal 2 is 4m
If m, the thickness of the auxiliary jig 4 is set to 2.5 mm or the like.

The surface of the auxiliary jig 4 facing the TV camera 3 is in the direction crossing the optical axis of the TV camera 3 (the auxiliary jig 4).
Illumination light is emitted by the illuminating device 6 from a direction intersecting the normal direction of the surface of the. The illuminating device 6 is formed in an annular shape and illuminates the TV camera 3 with illumination light so as to surround the optical axis of the TV camera 3 so that the shadow of the terminal 2 is not formed on the surface of the auxiliary jig 4. Further, the illumination light enters the auxiliary jig 4 from an oblique direction, so that the illumination light does not reach the inside of the through hole 5.

However, the illumination light from the illumination device 6 is diffused and reflected on the surface of the auxiliary jig 4, as shown in FIG.
As shown in, the light emitted to the tip of the terminal 2 is reflected in the direction toward the TV camera 3. Therefore, when viewed from the TV camera 3, the tip of the terminal 2 is bright,
The area around the terminal 2 corresponding to the through hole 5 is dark, and the surface of the auxiliary jig 4 around the through hole 5 is bright.

Therefore, by setting an appropriate threshold value for density with respect to the grayscale image captured by the TV camera 3, and binarizing the grayscale image using this threshold value, the terminal 2 and the periphery are clearly distinguished. It will be possible. Moreover, since the TV camera 3 images the tip end side of the terminal 2, all the terminals 2 can be brought into the field of view, and it is not necessary to image the terminal 2 from a plurality of directions as in the conventional case. When the binary image of the terminal 2 is obtained as described above, each terminal 2
The position of each terminal 2 can be determined by obtaining the position of the representative point such as the position of the center of gravity, and the interval between the terminals 2 can be obtained.

By the way, in order to measure the position of the terminal 2 with good reproducibility, it is necessary to accurately position the electronic component 1 with respect to the auxiliary jig 4. Therefore, FIG. 2 and FIG.
, The auxiliary jig 4 is integrally fixed to the fixed base 11 fixed at a fixed position, the electronic component 1 is placed on the fixed base 11, and the electronic component 1 is slid on the fixed base 11. The electronic component 1 is thereby positioned at a fixed position. Here, the electronic component 1 includes two FETs.
Is attached to the heat sink 17 as an example,
Each FET has three terminals 2 and the heat sink 17 is provided with two fixing pins 18.

A mark 12 formed by being embedded in the fixed base 11 is provided on the front end surface of the fixed base 11 so that a reference point can be shown, and the mark is passed through the sight window 7 formed in the auxiliary jig 4. So that you can see 12. The mark 12 is formed of a white synthetic resin so that the TV camera 3 can pick up an image as a bright area, and a material that is less likely to be deteriorated by light, mechanical shock, or the like is selected. The portion of the front surface of the fixed base 11 that can be imaged by the TV camera 3 through the viewing window 7 except the mark 12 is darkened in the image taken by the TV camera 3. Further, on the upper surface of the fixed base 11, slide grooves 14 having stepped mounting bases 13 on both sides are formed, and both side parts of the electronic component 1 are mounted on the mounting base 13 of the slide groove 14 as shown in FIG. The electronic component 1 is pushed forward from the rear by a pushing device such as an air cylinder. The width of the slide groove 14 is set to a width including the tolerance of the electronic component 1. In addition, one mounting table 13
And the side wall of the slide groove 14 adjacent to the upper surface function as a reference surface, and the electronic component 1 is placed by the downward pusher 15 and the lateral pusher 16 so that the electronic component 1 is pressed against the reference plane. It is pressed against the table 13.

With the above configuration, the electronic component 1 is imaged by the TV camera 3 while being positioned at a fixed position with respect to the auxiliary jig 4, and the electronic component 1 has a fixed reference position. The measurement can be performed under the same conditions, and the reproducibility of the measurement result is improved. Here, the illumination device 6 has, for example, a diameter D of about 20 as shown in FIG.
A 0 mm annular fluorescent lamp can be used. Further, the lighting device 6 is located between the TV camera 3 and the auxiliary jig 4, and the distance L ₁ from the TV camera 3 is about 300 mm and the distance L ₂ from the front surface of the fixed base 11 is about 50 mm. In addition, the optical axis of the TV camera 3 is a lighting device (fluorescent lamp)
It is arranged so as to substantially coincide with the center line of 6. By arranging the illuminating device 6 in this way, the angle θ of looking at the surface of the auxiliary treatment section 4 from the illuminating device 6 becomes smaller than about 45 °, and as a result, the illumination light enters the surface of the auxiliary jig 4. The angle is greater than about 45 ° with respect to the optical axis of the TV camera 3. Although not shown here, a reflector is also provided so that the surface of the auxiliary jig 4 is brightly illuminated. The irradiation angle of the light from the illuminating device 6 to the surface of the auxiliary jig 4 is selected such that the light does not enter the inside of the through hole 5 and the amount of light reflected on the surface of the auxiliary jig 4 is large. Therefore, the lighting device 6 can be moved back and forth with respect to the auxiliary jig 4 so as to obtain a desired lighting condition. Therefore, the lighting device 6 is adjusted and fixed at the optimum position.

By the way, the TV camera 3 picks up an image in response to a start signal from the sequencer 8 and inputs the image to the image processing device 9 which is a computer device. The image captured by the TV camera 3 is as shown in FIG. 4 (this image is upside down from the actual object due to the positional relationship between the TV camera 3 and how the coordinate axes of the image are taken). The shaded area in FIG. 4 is a darker area than other areas, and if the density is appropriately set to a threshold value and binarized so that the shaded area and the other area can be separated, 2,
The mark 12 and the fixing pin 18 can be easily separated from other parts. That is, the grayscale image captured by the TV camera 3 is binarized by the image processing device 9, and the position of the center of gravity of the tip of each terminal 2 is obtained. Here, since the two marks 12 are also captured by the TV camera 3, the reference line and the reference point in the image can be defined by the images of both the marks 12, and each of the reference lines and the reference points can be defined. The position of the image of the terminal 2 can be obtained. That is, as described above, since the electronic component 1 is positioned at the fixed position with respect to the mounting base 13 by the downward pressing device 15 and the lateral pressing device 16, the reference surface set on the mounting base 13 and the positions of the marks 12 are set. By calculating the relative difference of 1 by software, the reference point of the electronic component 1 can be obtained from the mark 12, and the positions of the terminal 2 and the fixing pin 18 can be obtained with good reproducibility. Further, it is desirable to fix the two so that the coordinate axes of the TV camera 3 and the reference surface of the mounting table 13 are parallel to each other, but in reality, as shown in FIG.
Since the TV camera 3 and the mounting table 13 have a mounting error of about several tens of microns and the reference plane is tilted with respect to the coordinate system (x'-y ') of the apparatus, both ends of the reference line determined by the two marks 12 are attached. Coordinate conversion (rotation) is performed so that the y-coordinates of the marks 12 are equal (that is, converted into the coordinate system (xy) with the mounting table 13 as a reference) to correct the coordinate values.

The result thus obtained is compared with the desired position of the terminal 2, and if the comparison result exceeds the tolerance, the electronic component 1 is determined to be a defective product, and the result of the quality determination is sequencer. Return to 8. Further, the area corresponding to the through hole 5 is not formed around the area corresponding to the terminal 2,
When the terminal 2 and the peripheral edge of the through hole 5 are in contact with each other, the product is determined to be defective. Further, the operation time of the pushing device for pushing the electronic component 1 forward is limited by the timer so that the defective product can be determined even when the terminal 2 is not inserted into the through hole 5. When the electronic component 1 is not pushed to the fixed position (when it is a cylinder, it does not extend to a predetermined length), it is determined as a defective product without imaging the terminal 2. Here, if there is no problem in the characteristics of the electronic component 1 even if it is a defective product, the terminal 2 is corrected and manual mounting work is performed. Further, the fixing pin 18 of the heat sink 17 is generally made of copper plated with solder, and in most cases, since it is within the tolerance, no correction is performed. In this way, the position of the terminal 2 can be accurately obtained, which leads to ensuring the quality and improving the insertion rate when the electronic component 1 is automatically inserted.

Although an annular fluorescent lamp is used as the illumination device 6 in the above embodiment, the type of light source is not limited to the fluorescent lamp, and the shape of the auxiliary lamp is not limited to the annular shape. If the tool 4 can be irradiated with light from an oblique direction and the shadow of the terminal 2 is not formed,
It may have a horseshoe shape or the like. Further, although the TV camera 3 is used as the image pickup device in the above-described embodiment, another image sensor or photoelectric sensor may be used as long as it can image a two-dimensional shape, and an electronic device using a one-dimensional image sensor is used. Two-dimensional information may be captured by scanning one of the component 1 and the image sensor. The opening shape of the through hole 5 may be circular, but may be set so as to match the cross-sectional shape of the terminal 2, for example, as shown in FIG.
If the cross-sectional shape of the terminal 2 is rectangular as in (a), the opening shape of the through hole 5 is also rectangular, and if the cross-sectional shape of the terminal 2 is triangular as in FIG. The opening shape may also be triangular. In this way, if the auxiliary jig 4 is changed according to the position and shape of the terminal 2, it is possible to cope with various types and the cost performance is improved. Furthermore, the illumination device 6 does not necessarily have to irradiate the surface of the auxiliary jig 4 with light.
Light from the rear surface of the auxiliary jig 4 as shown in FIG.
7 to irradiate the light and diffuse and transmit the light with the auxiliary jig 4.
As shown in (b), the light source 10 is provided on the side of the auxiliary jig 4, and the auxiliary jig 4 is formed of a transparent material such as glass or acrylic, and is optically coupled to the light source 10 directly or by an optical fiber. A part of the light that travels while being repeatedly reflected inside the tool 4 may be extracted from the diffuse transmission surface of the surface of the auxiliary jig 4. In the case of the configuration shown in FIG. 7B, it is desirable that a reflective surface is formed on the rear surface of the auxiliary jig 4 and a white or yellow diffuse transmission surface is formed on the front surface of the auxiliary jig 4. In any case, any structure may be used as long as the diffused light is emitted from the surface of the auxiliary jig 4 to the tip of the terminal 2.

In the above embodiment, the FET is used as the electronic component 1.
However, the electronic component 1 may be another one such as a capacitor, a bipolar transistor, or an integrated circuit. Any electronic component other than the electronic component 1 may be used as long as a pin-shaped object is provided so as to project. The technical idea of the present invention can be applied.

[0023]

As described above, according to the present invention, since the pin-shaped object is imaged from the tip end side by the two-dimensional imaging device, the pin-shaped objects do not overlap in the visual field of the imaging device, and the pin-shaped object can be viewed from one direction. Since only the pin-shaped object needs to be imaged, the process for determining the pin-shaped object arrangement interval is simplified, and as a result, the pin-shaped object arrangement interval can be accurately and easily obtained. In addition, each pin-shaped object is inserted through the through hole provided in the auxiliary jig so that the tip of the pin-shaped object protrudes from the auxiliary jig, and the pin-shaped object is entirely covered from one surface of the auxiliary jig. By irradiating a diffused light beam, the surface of the auxiliary jig and the tip of the pin-shaped object can be made brighter than the inside of the through hole of the auxiliary jig. As a result, the pin-shaped material can be clearly extracted by a simple process such as binarization depending on the concentration.

[Brief description of drawings]

FIG. 1 shows an embodiment, (a) is a schematic configuration diagram, and (b) is an operation explanatory diagram.

FIG. 2 is an exploded perspective view of a main part of the embodiment.

FIG. 3 is a diagram showing an overall configuration of an embodiment.

FIG. 4 is a diagram showing an example of an image obtained by an example.

FIG. 5 is a diagram showing an example of an image obtained by the embodiment.

FIG. 6 is a diagram showing an example of an image using an auxiliary jig having another shape in the example.

FIG. 7 is a cross-sectional view showing another example of the lighting device used in the embodiment.

FIG. 8 is a schematic configuration diagram showing a conventional example.

FIG. 9 is a configuration diagram of a main part showing another conventional example.

FIG. 10 is a diagram showing an example of an image according to the conventional example of FIG.

FIG. 11 is a diagram illustrating a problem in the conventional example of FIG.

[Explanation of symbols]

 1 electronic component 2 terminal 3 TV camera 4 auxiliary jig 5 through hole 6 lighting device

Claims (1)

[Claims] 1. A plurality of pin-shaped objects, which are arranged substantially parallel to each other and whose tip portions are tapered, are formed by a two-dimensional imaging device having an optical axis substantially aligned with the longitudinal direction of the pin-shaped objects. In a pin-shaped object arrangement interval measuring method, which captures an area including the tip of the object and detects the position of the pin-shaped objects based on the brightness of each part of the captured image to determine the arrangement interval of the pin-shaped objects. , Each auxiliary hole of the auxiliary jig is formed by using an auxiliary jig in which a plurality of through holes having an opening area slightly larger than the cross section orthogonal to the longitudinal direction of the respective pin objects are formed so as to correspond to the respective pin objects. Each of the pin-shaped objects is inserted into each of the auxiliary jigs so that the tip of the pin-shaped objects protrudes toward the imaging device side with respect to the auxiliary jig. A pin characterized by irradiating a diffusive light beam around the circumference Method for measuring the arrangement interval of objects.