JPH08210820A - Method and device for recognizing part to be inspected in visual inspection device of parts-mounted board - Google Patents

Abstract

PURPOSE: To determine an IC-mounting polarity and at the same time accurately detect an IC-mounting position by detecting the brightness level of each picture element from a video signal which is obtained by picking up the image of an object to be inspected. CONSTITUTION: Light is applied from a light 1 in a multiple-stage structure (four-stage ring shape) whose light projection angle differs. Reflection light via an IC package 10 to be inspected is received by an image pick-up device 2. A plurality of sets of video signals obtained by switching lighting are stored in an image storage 5 in the form of brightness pattern of a target surface. A code generation part 7 detects the brightness level for each picture element to be inspected based on the storage contents of the image storage 5 and generates a code pattern indicating it. Further, a recognition processing part 9 recognizes the solid shape of a target and judges the conformity by utilizing it. Using this method, an electrode mark part can be extracted as an image change position or a region even in the case of a black plastic IC package with a low brightness level of a detection target and a small image.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a plurality of sets of illuminators having different irradiation characteristics of light to an inspection object, for example, irradiation angles, and displays a plurality of image information obtained by sequentially switching the irradiation light to the object. Based on the appearance inspection device that recognizes and determines the appearance state of the inspection object based on the above, for example, the mounting position of the electronic component on the printed wiring board, the appearance shape and the appearance state of the object having a glossy surface such as a soldered joint. The present invention relates to a recognition processing method in an inspection device for making a pass / fail judgment, and more specifically, to a method and device for detecting the position and direction of an inspection target component using the plurality of pieces of video information or a part thereof.

[0002]

2. Description of the Related Art There are various fields of application of appearance inspection machines, and there are various inspection methods. For example, the mounting state of electronic components on a printed circuit board, which has been increasing in density and diversification recently, and a visual inspection machine for soldered joints are examples.

That is, in the mounting process of a printed wiring board used for electronic equipment, the quality of the soldered portion for joining the electronic components mounted on the board affects the product reliability, so that the work efficiency is improved and the work is improved. The automation and mechanization of soldering visual inspection have become common for the purpose of ensuring quality. In addition to the soldering inspection, it is also important to inspect the mounting position and mounting direction of components. That is, even if there is no abnormality in the solder joint, if the polar capacitors or the ICs are mounted in opposite directions, a fatal problem occurs in the performance of the electronic device.

Conventionally, appearance inspection machines for electronic parts are divided into a soldering quality inspection machine and an inspection machine for the mounting state of the parts themselves. However, with the recent shift to high-mix low-volume production, an increasing number of multi-function inspection machines combine both functions into one inspection machine. With such an inspection machine, it has become possible to detect misalignment and missing parts of electronic components, and the mounting polarity of a polar capacitor from a grayscale image, in addition to the solder quality judgment. However, with respect to the mounting direction of the IC, since the polarity discriminating mark originally set for visual inspection is minute and difficult to detect, it is not established as an inspection function, and in general, silk printing is performed on the upper surface of the IC. The method has been adopted in which a mounting inspection machine capable of recognizing the written characters is also installed.

Therefore, it has been demanded to add such a function to the soldering appearance inspection machine itself at the same time as the development of a recognition method capable of more reliably executing the IC polarity discrimination.

Here, more specifically, an example of the IC polarity discrimination mark will be described.

FIG. 2 is a top view of the IC package 10. Actually, a lead (not shown) is provided in four directions of up, down, left and right in the figure.
Is arranged. The polar mark 10M of this part is on the lower right side of the figure (one of the four corners of the part is the mark 10M).
(Large cut as shown in, small cuts at the other three points)
At the cut part, the polarity can be discriminated and the mounting direction can be confirmed.

FIG. 3 is a top view of another type of IC package 11 in which the leads in the upper and lower two directions are omitted, and the polar mark 11M of this component is cut in a semicircular shape.

FIG. 4 shows another type of IC package 1.
2 is the upper surface, and the polarity determining mark is in the form of a press mark engraved in one corner of the upper surface of the package. The cross section of the press mark M has various cross sections as shown by the mark 12Ma and the mark 12Mb as shown in the enlarged view, but all of them are circular and have different diameters depending on the types of parts. . The sectional view is exaggerated in the vertical direction, and the actual depth is extremely small (for example, 10
(Dimple around 0 micron). 2, FIG. 3, and FIG. 4, reference numeral 13 denotes an upper surface portion of the IC package, and 14 denotes a chamfered taper portion formed around it.

As described above, the mounting polarity of the IC must be determined by the presence or absence of a cut mark or a circular mark at a predetermined position.

[0011]

For example, the polarity determination and the attachment position determination of the IC package as described above have the following problems.

1) The image to be detected is weak: the IC package is generally made of black plastic so that the optical reflection level is low, and the mark portion is extracted as the image change position or region through the IC package. Must.

2) Various backgrounds: On the peripheral substrate on which the IC is mounted, in addition to a simple resist surface, a portion where the image level is relatively high compared to the mark image such as silk printing and wiring. Therefore, it is necessary to recognize a desired part position or mark from an image including such a background.

3) Various disturbances: The IC package portion to be detected has different reflection characteristics depending on the material and the processing method depending on the type of parts, and in some cases, the drift of the reflected luminance level due to illumination fluctuations. May occur.

The present invention, as described above, has been difficult in the past.
It is an object of the present invention to provide a recognition method capable of accurately detecting the mounting position of an IC at the same time as determining the mounting polarity of the C.

More specifically, the present invention provides a recognition method and apparatus capable of projecting illumination light onto a target surface, converting reflected light from the target into a video signal by an image pickup device, and performing the above detection from the video signal. It is an object.

Another object of the present invention is to integrate the above-mentioned recognition method into a conventional soldering quality inspection machine and combine it by adopting such a method and apparatus.

Further, according to the present invention, the image information generated for inspecting the solder joint portion can be utilized at the same time for the displacement of the IC and the determination of the mounting polarity.

[0019]

FIG. 1 shows a flowchart of the basic principle of a recognition processing method according to the present invention for solving the above problems.

In the present invention, the inspection target position is roughly divided as required. That is, 1) -1: In order to limit the inspection target range from the image pattern of the imaged target inspection target component, the case where the inspection target image level is below a certain value and the area above the certain value is outside the target range. To do. 1)-
2: Furthermore, the inspection target range is limited by the teaching information.

Here, the target position outline divisions of 1) -1 and 1) -2 are not always essential in the present invention, but reducing the inspection range by such a method shortens the inspection time. Is effective in achieving

In this way, at the stage where the inspection range is limited, 2): In order to further obtain image conversion conditions such as a threshold value from the range limited by 1), the typical reflection of the relevant portion is performed. Set the sampling area at the position showing the characteristics,
Sampling the image of the part to be inspected. 3): In this way, the sampled image pattern signal of the inspected component is converted into a simplified pattern by performing image conversion processing such as binarization for each pixel of the target portion. 4): The electrode mark is detected by recognizing the simplified pattern of the target portion.

The image detected in this way is an extraction of a detection target, and by utilizing this, detection processing according to the purpose of inspection, such as detection of the boundary position and change position of the target, is performed.

[0024]

By excluding unnecessary regions in the target position outline classification, the inspection target range is limited, and various background images can be virtually deleted. Therefore, the recognition process is relatively easy even when the target video level is low. Become. Even if the information indicating the outside of the target range is local or discrete on the screen, if the basic shape of the inspection target and the mounting conditions are specified, the target range covers a considerably large area including the local information. It can be classified as outside. Thereby, the inspection time can be shortened. On the other hand, depending on the mounting conditions of parts and the positional conditions of the inspection target, the above-mentioned target position outline classification can be omitted. However, even in such a case, limiting the processing range of the target video level makes it possible to detect an abnormal condition. Has the meaning of enabling.

By sampling the target image of a portion showing a typical reflection characteristic, it is possible to obtain information for confirming the area of the target component, that is, a threshold value, regardless of variations in illumination and changes in the reflection characteristic of the target component. Therefore, it is possible to deal with various disturbances by image conversion processing such as binarization or multi-value conversion processing. As the method of determining the conversion conditions,
Various methods can be considered according to the type and purpose of the target, such as using the concentration distribution position based on the measurement result of the brightness distribution histogram in the sampled video, using the brightness average value or representative value, and checking the roughness of brightness variation. To be The target portion thus obtained is characterized, and the simplified pattern data is used to perform detection processing according to the inspection purpose by pattern recognition, such as detection of the boundary position and change position of the inspection target.

By using the principle of the present invention described above, it is possible to surely determine the mounting position deviation and mounting polarity of various ICs. In particular, the principles of the present invention work most effectively when using imaging means with multi-tiered annular illumination.

The concept of the present invention can also be used as a general means in various inspections other than IC inspection on a printed circuit board.

[0028]

EXAMPLES Examples of the present invention will be described below in the case of an IC as an example of an electronic component mounted on a printed circuit board.

In the case of the IC as the object of the embodiment, the mark indicating the electrode to be detected is a part of the package cut or pressed. Therefore, in the case of a cut mark, the end boundary position of the upper surface of the package is detected. In the case of a press mark, the circular boundary positions on the upper surface of the package may be detected. These boundary positions are formed as chamfers from the upper surface of the package or taper portions.

When the package having such a structure is closed up and the mark shape is extracted, in addition to the illumination for irradiating the target IC from the upper surface, an illumination device for irradiating from the tilt direction is installed. However, a multi-stage illumination type inspection device capable of utilizing a plurality of images by these irradiation devices is advantageous.

In particular, like ICs, the boundary positions of parts and marks
In the case where the component is composed of a taper portion having a slope with respect to the upper surface of the component, an image by inclined illumination is effective for extracting the boundary portion.

That is, when the image pickup device is installed in the upper direction and directly above, the illumination light from the upper stage mainly receives the reflected light on the upper surface of the component (the plane intersecting the optical axis of the image pickup device at right angles) and the lower stage light. This is because the illumination light from the tilt direction causes the image pickup device to mainly receive the reflected light of the chamfered taper portion (a plane that obliquely intersects the optical axis of the image pickup device).

Considering that the press marker is circular and the cut portion is also installed in 4 to 8 directions on the printed circuit board plane depending on the component mounting conditions, the illumination is centered on the optical axis of the image pickup device. The ring-shaped one set to is suitable.

The present invention does not necessarily need to use such a step illumination type inspection apparatus, but since it is an apparatus which can most effectively carry out the present invention, an example using this apparatus will be described below.

Regarding the step illumination type inspection apparatus itself, for example, the basic principle is shown in JP-B-5-21403.

FIG. 5 is a view showing a basic system configuration of a step illumination type inspection apparatus, 1 is a ring-shaped illuminator, 1-1 is an upper stage illumination, 1-2 is a middle upper stage illumination, 1-3 is a middle lower stage illumination. , 1-
Reference numeral 4 is a lower illuminating device. Reference numeral 2 is an image pickup device such as a television camera, 3 is a moving table for moving a substrate on which the IC package 10 to be inspected is mounted, 4 is a video signal of the image pickup device 2, 5 is a storage device including an AD converter, and 6 is a lighting switch. apparatus,
Reference numeral 7 is a code generation unit, 8 is a moving table control device, and 9 is a recognition processing unit.

Next, this operation will be described. Illuminator 1 with a multi-stage structure with different light projection angles (in the figure, 4 stages are ring-shaped)
Light is emitted from. IC package to be inspected 1
The reflected light passing through 0 is received by the image pickup device 2, and a plurality of sets of video signals obtained by switching the illumination are stored in the image storage device 5 in the form of a luminance distribution pattern on the target surface. Remembered. Based on the contents stored in the image storage device 5, the code generator 7 generates a code pattern indicating the brightness level for each pixel to be inspected. Further, by utilizing this, the recognition processing unit 9 executes recognition of the three-dimensional shape of the target and determination of quality. The operation flowchart of this recognition processing is as shown in FIG. The code generation unit 7 uses a ring-shaped illumination in a practical machine for soldering inspection.
From the brightness levels of a plurality of images obtained by switching the upper, middle upper, middle lower, and lower stages, an angle code, which is described in 8 to 10 steps, from the flat portion to the steep angle portion of the object is generated in pixel units. To do. The shape of the inspection target is determined from the distribution state of the angle codes by the recognition device in the subsequent stage. However, I
In principle, it is not necessary to obtain the angle code in the detection of the mark of the C package. Therefore, in this embodiment, the inspection by the code indicating the brightness level is performed as described above.

In the inspection apparatus having such a configuration, the image signal obtained for each illumination naturally includes the information suitable for the above-mentioned IC positional deviation and polarity discrimination, so that the positional deviation and polarity can be recognized. Become.

The contents of the present invention will be described in further detail below with reference to an embodiment in which the mounting position and mounting polarity of an IC component are used as a model.

As described above, in the exemplary embodiment of the present invention described below, it is not always necessary to use all the image information obtained by switching the step illumination.
It is only necessary to use the stage illumination (only one stage) that most accurately represents the state of the surface to be detected by the reflected light from the inspection surface. Therefore, the image information obtained from the image pickup device is not the angle code data for each pixel as in the case of the above-described solder inspection but data representing the brightness.

In the following, in the present embodiment, as an example, there are seven types of brightness levels of code: A, B, a, b, c, d, e. Note that, in a practical machine, for example, 256 multi-gradation luminance levels are used.

6 and 7 are explanatory views of an embodiment for recognizing the presence / absence of the polarity mark 10M in the IC package shown in FIG.

First, in order to distinguish the approximate detection target position, since the correct mounting position and polarity on the printed circuit board are given in advance as teaching information to the inspection machine, mounting is performed at the position based on this information. Set the inspection window.

The image of the relevant portion picked up by the image pickup device 2 passes through the storage device 5 and is generated in the code generator 7 as a pattern of code distribution according to the brightness level. The coded video in this window is shown in Figure 6 (i).
Shown in In the figure, 13 is the upper surface of the IC package, 14 is the chamfered taper portion around the package, and 15 is the IC lead. As described above, the codes A, B, a, b,
c, d, and e indicate the brightness level corresponding to each pixel. In the case of this example of FIG. 5, the image illuminated by the lower stage illumination 1-3 or 1-4 of FIG. 5 is shown, and the taper portion which has the same slope as the upper surface of the package even if the same material is used. However, the brightness level is high on average.

The relationship between high and low brightness level codes is as follows.

B >>e>d>c>b> a << A First, when the image in the window is surveyed, the lead 15
It can be seen that the portion of (1) has an extremely high luminance level as compared with the package to be inspected. It is known from the teaching information that the IC package in the window is installed in the lower right corner of the window (that is, the upper left portion of the IC package in the window). Area with high brightness level, that is, left of window (arrow XX
Is shown), and the upper side (shown by an arrow YY) is determined not to be an inspection target. In this way, the non-inspection target is separated as shown by the dotted symbols in FIG. 6 (iii).

This is the 1) target position schematic division of FIG. 1 described above.

This rough division of the target position is performed as necessary, and reducing the inspection range by such a method is effective in shortening the inspection time.

Note that this information indirectly gives the existence of the IC and its approximate position.

Next, 2) detection target image sampling in FIG. 1 is performed. This is to sample a portion showing a characteristic and typical reflection characteristic of the detection target portion. That is, a video sampling area 102 having a certain area (that is, a specific range) is set on the IC package,
Check the frequency distribution of the brightness levels in this area. In this case, the frequency distribution within the sampling area 102 is shown in FIG.
As indicated by the solid line in (ii), the characteristic is concentrated with the brightness level b as the center.

Therefore, the lower limit value Sb is centered around the brightness level b.
1, the upper limit value Sb2 is determined as the threshold value. By using the threshold value, the lower limit value Sb1 and the upper limit value Sb2, the image in the window is binarized in order to divide the image for each pixel by state,
An image of the 1/0 code pattern of FIG. 6 (iii) is obtained.
This is the video conversion process such as the 3) binarization process in FIG. 1 described above.

The position and shape of the package can be detected when such an image is obtained.

The representative value of the brightness level which is the reference for determining the threshold value is, as shown in FIG. 14, the most frequently occurring value: a, or the average value: b, or the median value: c, etc. Select according to the situation. In the figure, the vertical axis represents the frequency of occurrence and the horizontal axis represents the brightness level.

Next, 4) target position detection in FIG. 1 is performed.
This will be described with reference to FIG. 1/0 code pattern
FIG. 7 shows an IC mounting position and a mounting polarity determining method at the step of mounting. First, in the image of FIG. 7 (i), when the number of code 1 in each row in the y direction of the figure is examined, the characteristic of (ii) is obtained, and the position where the number rapidly increases is determined in the y direction of the package. It is detected as the boundary position. Similarly, as shown in (iii), the x-direction boundary position is detected. Based on the position detected in this way, a triangular area having the same area as the virtual cut portion is set, and images in both areas or 1/0 code information are compared. If it is a cut screen, there is a large difference in the images in both areas or in the 1/0 code distribution. If there is no cut part, there is no significant difference in the images in both areas or the code distribution. The presence or absence of can be determined. This method corresponds to a simple template matching method, but is extremely effective when the inspection purpose is limited. It is often the case that the discrimination performance is improved by providing a dead zone between the two areas. Further, the region may have a shape other than a square, and is not necessarily the same size.
Note that a method of comparing the package position shape detection result with the teaching length of the cut portion can also be used to determine whether or not there is a cut.

If necessary, the image of the taper portion can be further extracted. Returning to FIG. 6 described above, using the position detection result, the sampling area 104 is set in the taper portion 14 as shown by the dashed line in FIG. 6 (i), and the dashed line in FIG. 6 (ii) obtained from this is set. From the characteristics of Fig. 6, when the lower limit value Sd1 and the upper limit value Sd2 are set as threshold values centering on the brightness level d and the image of the target area in the window is binarized, the image of the pattern of code 2 in Fig. 6 (iii) is obtained. Is obtained.
The detection of the cut portion is as described above.

Next, an embodiment of the recognition system of the circular press mark 12 shown in FIG. 4 will be described with reference to FIGS. 8, 9 and 10.

FIG. 8 shows a model of the luminance level distribution around the press mark on the IC package surface. FIG. 8 (i) shows, for example, the mark 12Ma in FIG.
Similarly, (i) is an image corresponding to the mark 12Mb in FIG. 4, and the circle shown by the broken line corresponds to the press mark. In all cases, it is assumed that the non-inspection area has already been removed, or the non-inspection area does not exist in the inspection window due to the positional relationship between the package boundary and the mark.

First, FIG. 8 (ii) is obtained by measuring the luminance distribution of the image of FIG. 8 (i). The clearly separated amphoteric histogram shows the existence of two regions having different average luminances. Therefore, the respective central values, b and d
Based on the threshold values St1 to St2 and St3 to St4
Is set to obtain the ternary image of FIG. 8 (iii).

On the other hand, the luminance distribution of the image of FIG. 9 (i) is shown in FIG.
(Ii). In this case, since the bilaterality is weak, the threshold values St1 to St are set based on the brightness b having a high degree of concentration.
2 and the lower limit threshold value St3 based on the luminance at a fixed position from the distribution end of the histogram; St3 is set to obtain the ternary image of FIG. 9 (iii) in order to distinguish the states. Such setting of the threshold value St3 is effective in the target extraction when the target signal component in the background is biased to one of high and low, and is set from the end of the distribution range according to the size and shape of the target. Determine the position. If it is unknown whether the distribution range is in the upper limit direction or the lower limit direction, the recognition results of both sides must be compared and evaluated.

Next, FIG. 10 shows an embodiment of a circular mark recognition system based on the image of FIG. 8 (iii). However, in order to simplify the explanation, the code 1 portion is converted into 0. Image correlation is generally used as a method of recognizing a circle from such a binarized image, but in the case of this embodiment, this is simplified and used. First, the image is subjected to number integration in the x and y directions in the figure. As a result, the integral characteristics shown in FIG. 10 (ii) and FIG. 10 (iii) are obtained, so that the center position of the mark to be inspected is detected with reference to the diameter of the circle given in advance. That is, Hx and Hy, which correspond to the diameter of the circle and have the highest integrated value cumulative density, are determined, and the intersection of the center positions Px and Py of these ranges is set as the center position of the mark.

Next, referring to the mark center as shown in FIG.
As shown by the broken line in (i), four symmetrical regions are set, and the number of code 2 in each region is examined. The ratio of the number of codes in these four areas to the total number of codes in the window is used as an index for determining whether or not the object is circular, and the symmetry of the number of codes in each of the four areas is used. As the area setting method used for image correlation, various methods such as a more circular shape or an annular shape can be used.

Although the embodiments of the cut and circular mark recognition have been described above, the semicircular cut mark 11M shown in FIG.
As for the recognition of the above, it is needless to say that it can be sufficiently recognized by applying the above-described method or the modified method, if the opposite side of the mark is on a straight line.

FIG. 11 is a flowchart showing an embodiment of a recognition method for the case where the IC position shift or polarity determination is performed.

As described above, the above embodiment can be implemented by using any one of the step illuminations shown in FIG.

On the other hand, the advantage of the multistage illumination is that a plurality of images for recognizing the object can be prepared. Therefore, by utilizing this, it is possible to further strengthen the inspection function and improve the performance. If the mark cannot be recognized in the image by the illuminator of one stage shown in FIG. 5, for example, the illumination of 1-4, the illuminator of the other stage, for example, 1-3, for confirmation.
It is also possible to adopt a method of performing recognition using an image by the illumination. This operation flowchart is shown in FIG.

Although not shown in the figure, when the target extracted image S / N of the image by one stage of illumination is poor, S is obtained by comparing or adding the target extracted image of the image by the other stage of illumination.
It is possible to improve / N.

Further, regarding the 1) target position schematic division of FIG. 1, when the step illumination type inspection machine of FIG. 5 is used, it has excellent characteristics as described below with reference to FIG.

FIG. 12 shows the distribution of the brightness levels of the special lighting 1-1, 1-2, 1-3, 1-4 when the IC on the printed circuit board is inspected. In this figure, there are four stages of ring-shaped illumination, that is, the irradiation angles with respect to the inspection object are different.
3 shows a relative comparison of the brightness levels around the target in the case of using 3 and the lower stage illuminations 1-4. As shown in the figure, I
The image of the area to be inspected, such as the top surface of the package of C, the taper surface, and the press mark, shows a relatively low level (package portion P) under any illumination, whereas the image of the background substrate. The silk-printed part (silk-printed part S) has a higher brightness level. Further, the lead portion (lead portion L) of the IC has a considerably high brightness level.

Therefore, in the luminance level of each step illumination image, the portion above the threshold value St shown by the broken line can be effectively used for partitioning the region showing the non-inspection object. That is,
In addition to the classification based on the teaching information and the classification based on the two threshold values described in the previous embodiment, the general classification of the target position based on one threshold value is also possible.

The advantage of multi-stage illumination is that a plurality of images for recognizing an object can be prepared. Therefore, by utilizing this, it is possible to further strengthen the inspection function and improve the performance. For example, as shown in FIG.
Illuminators of two of the four lightings, such as 1-1,
When the brightness level due to the illumination of 1-2 overlaps the silk print section S and the package section P, the mark cannot be recognized, but even in such a case, the illuminator of another stage, for example, the lead section L, It is also possible to adopt a method of performing recognition using an image by the illumination of the illuminator 1-3 in which the difference between the silk portion S and the package portion P is largest. This operation flowchart is shown in FIG.

As in the above-described embodiment, the inspection device for inspecting the soldering state using the image information obtained by switching the step illumination which has been put into practical use (for example, Japanese Patent Laid-Open No. 4-301549, If the principle of the present invention is combined with a soldering inspection device of a multi-stage ring illumination system among those disclosed in Kaihei 4-346011, JP-A-5-301549, JP-A-6-66528, etc. This is convenient because there is no need to add a new mechanism section for determining the polarity.

In the above description of the embodiment, the embodiment was described in which the position shift and the polarity discrimination of the IC mounted on the printed circuit board were used as a model, but the invention can also be used for parts other than the IC, such as a polar capacitor. It goes without saying that the basic idea of the present invention can be applied to other inspection targets.

[0073]

As can be seen from the above description, according to the present invention, even if a black plastic IC package having a low luminance level to be detected and a weak image is detected, an electrode marker is used as an image changing position or area. -The black part can be extracted.

In addition to the resist surface, there are various backgrounds such as silk printing and wiring on the peripheral substrate on which the IC is mounted, and these have a relatively high luminance level compared to the mark image. In both cases, it is possible to recognize the target component position or mark from the image including such a background.

It can be applied to the inspection of various IC packages having different reflection characteristics depending on the material and the processing method depending on the type of parts. Further, since the detection is based on the relative value of the brightness level, it is possible to avoid the influence of the drift of the reflected brightness level due to the fluctuation of the illumination.

As described above, according to the present invention, the mounting state of the IC mounted on the printed circuit board, particularly the mounting polarity which has been difficult to inspect in the past, can be easily determined, and the effect from an industrial viewpoint is great. . In particular, the conventional solder inspection device lighting device,
Since the image pickup device is used as it is and the obtained image data can be commonly used, it can be integrated with the solder inspection device. Therefore, the effect is great in terms of price and usability.

[Brief description of drawings]

FIG. 1 is a flowchart of an object recognition basic process according to the present invention.

FIG. 2 is a plan view showing marks on an IC package.

FIG. 3 is a plan view showing marks on an IC package.

FIG. 4 is a plan view showing marks on an IC package.

FIG. 5 is a configuration diagram of a step illumination inspection apparatus showing an embodiment of the present invention.

FIG. 6 is an explanatory view showing a process of an embodiment of the present invention.

FIG. 7 is an explanatory view showing a process of an embodiment of the present invention.

FIG. 8 is an explanatory view showing a process of an example of the present invention.

FIG. 9 is an explanatory view showing the steps of the embodiment of the present invention.

FIG. 10 is an explanatory diagram showing a process of an example of the present invention.

FIG. 11 is a flowchart of an embodiment of the present invention.

FIG. 12 is a level illumination brightness level diagram for explaining an embodiment of the present invention.

FIG. 13 is a level illumination brightness level diagram for explaining an embodiment of the present invention.

FIG. 14 is a luminance level distribution diagram illustrating an embodiment of the present invention.

[Explanation of symbols]

1 ring-shaped illuminator, 2 imaging device, 5 storage device, 6
Lighting switching device, 7 code generation unit, 8 moving table control unit, 9 recognition processing unit, 10 IC package, 10M
Electrode mark, 11 IC package, 11M electrode mark, 12IC package, 12M electrode mark,

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G06T 5/00 H05K 13/08 Q 7128-4E

Claims (4)

[Claims] 1. A method of inspecting an attachment state such as an attachment position and an orientation of a component mounted on a board, in which a luminance level of each pixel is detected from a video signal of an image of an object to be inspected and the luminance level information is inspected. Sampling the luminance level in a specific range showing typical characteristics in the target range, obtaining a threshold value from the sampled luminance level, classifying each pixel in the inspection range by the state by the threshold value, A method of recognizing a portion to be inspected in a visual inspection apparatus, which recognizes a component mounting state of the portion to be inspected from the classified pixel pattern. 2. A method of inspecting an attachment state such as an attachment position and an orientation of a component mounted on a board, detecting a luminance level of each pixel from a video signal of an image of an object to be inspected and inspecting from the luminance level information. The target range is limited, the luminance level in a specific range showing typical characteristics within the limited range is sampled, a threshold value is obtained from the sampled luminance level, and each pixel in the inspection range is determined by the threshold value. Method for recognizing a part to be inspected in an appearance inspection device, characterized in that the parts mounting state of the part to be inspected is recognized from the classified pixel patterns. 3. A method of inspecting a mounting state such as a mounting position and a direction of a component mounted on a board, in which a luminance level of each pixel is detected from a video signal of an image of an object to be inspected and the inspection is performed from the luminance level information. A target range is limited, a sampling range of a limited range that shows typical reflection characteristics of the inspection target part is set from the limited inspection range, an image of the limited range is sampled, and the sampled limited range Of the brightness level of the inspection range is binarized based on the two thresholds, that is, an upper limit value and a lower limit value based on the brightness level. To the position and the direction of the inspection target within the inspection target range are recognized. 4. An imaging device is provided in an upper space of an object to be inspected, and a plurality of light sources arranged in a ring shape around the optical axis of the imaging device are arranged in a plurality of stages, and the object to be inspected is illuminated by the light sources. A step illuminating device that receives reflected light from an inspection target by the image pickup device and converts it into an electric signal, and a storage device that stores an image corresponding to the luminance level of the inspection target converted into the electric signal by the image pickup device, A limited range that limits an inspection target range from the brightness level information based on the luminance level code of the inspection target stored in the storage device, and indicates a typical reflection characteristic of the inspection target portion from the limited inspection target range. The sampling area of the limited area is set, the image of the inspection object component of the limited area is sampled, the representative luminance level of the sampled limited area is obtained, and the luminance level is used as a reference. Two thresholds, a limit value and a lower limit value, are provided, and each pixel in the inspection range is classified according to its state by the threshold value, and the position and direction of the inspection target are detected from the pattern of the classified pixels. Device for recognizing a portion to be inspected in a visual inspection apparatus, characterized in that