JPH0399250A - Mounting state recognizing apparatus - Google Patents

Abstract

PURPOSE:To enable recognition of a mounted state of a chip part at a high speed by recognizing a mounted state of parts from a shadow image data containing shadow data of the parts to set a recognition area for the shadow data of a part not recognized for re-recognition. CONSTITUTION:A lighting device 25 is lighted with a lighting switching circuit 27 and a camera 28 takes a circuit substrate 23 containing a chip part 22 to output an image signal. The image signal is stored into image memories 31 and 32 via an A/D conversion circuit 29. Then, by a command of a control circuit 38, a lighting circuit 26 is put off with the circuit 27 and a lighting device 26 is lighted. The device 28 takes the substrate 23 again and an image signal is stored into the memories 31 and 32 via the A/D converter 29. A subtraction circuit 34 reads out a shade image data to subtract and the results are stored into an image memory 36 via a binary coding processing circuit 35. A projecting circuit 37 reads out an image data of the memory 36 to recognize a center coordinate, inclination and the like of the part 22 by a projection processing. A window is set for a shadow of a part not recognized to perform an operation for re-recognition.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a mounting state recognition device that recognizes a mounting state such as dropping or misalignment of a chip component mounted on a circuit board, for example.

(Prior Art) Electronic devices such as home appliances and office automation (OA) devices are becoming smaller and smaller, and along with this, the circuit boards used in each electronic device are also becoming smaller. For example, instead of a circuit board with lead wires, a circuit board on which small chipped resistors, capacitors, etc. can be mounted is used. Nowadays, due to the miniaturization of such mounted components, there is a demand for high-density mounting on circuit boards.

When mounting chip components on a circuit board, the chip components are first automatically temporarily mounted on a circuit board on which a predetermined wiring pattern has been formed using a mounting device, and then soldered using a soldering device. do. However, in such mounting, chip components often fall off or become misaligned, and if this is detected after soldering is completed,
You have to spend a lot of effort to fix it. Therefore, inspections are conducted to check for chip components falling off, misalignment, etc.

This inspection is performed visually by a worker, which requires a large number of personnel.Furthermore, since a plurality of chip components are mounted on a complex circuit board, there are many inspection errors. Furthermore, the detailed examination work is done all day long, which causes eye fatigue and poses health management problems.

For this reason, a method using image processing technology is being used to inspect the mounting state. This method includes the light cutting method, the pattern comparison method, and the oblique light shadow method. Among these methods, the light cutting method scans the cutting light obliquely with respect to the circuit board, and at this time, when viewed from above the circuit board, This technology takes advantage of the fact that there are steps in the cutting light depending on the height of the chip component. The pattern comparison method is a technique in which a pre-stored image of a good circuit board is prepared and image information of the circuit board to be inspected, such as gradation level and color, is compared for each pixel with this image. Furthermore, in the oblique light shading method, light is irradiated diagonally above the circuit board from opposing directions through the circuit board, and shadow information of the chip components is extracted from the difference in image data when these lights are irradiated. This is a technology for inspecting the condition of chip components. For example, FIG. 5 shows shadow image data when the circuit board is irradiated with light from the A direction and the B direction, respectively, and in this shadow image data, la and lb are relative to the chip component 2 in the A direction and the B direction. This is an image of the shadow that appears when light is irradiated from each direction. Similarly, 3a and 3b are the shadows of the chip component 4, 5a,
5b is the shadow of the chip component 6, and so on.

However, among the above methods, the optical cutting method requires the cutting light to scan the entire surface or part of the circuit board, so in order to detect rotational deviation of a square chip component, for example, it is necessary to irradiate each component two or more times. The inspection takes time because the direction has to be changed. Furthermore, in the pattern comparison method, each pixel must be compared many times, and inspection takes time. Furthermore, in this comparative method, the inspection accuracy and reliability are affected by the wiring pattern on the circuit board, the coating state of the resist, and the surface state of the chip component. Furthermore, although the oblique light shading method enables high-speed inspection by using the shadow information of chip components, it is difficult to inspect chip components when they are mounted adjacent to each other or due to the surface condition of the circuit board, as shown in Figure 5. Shadow information 5a and 9b of numbers 6 and 10 may be missing.

By the way, chip part 2 can be determined from such shadow image data.
, 4, 6, . . . , the window 13 is set to a size that allows for the misalignment of the chip components.
When recognizing, for example, the chip component 6 using this window 13, in addition to the shadow of the chip component 6, the shadows of the adjacent chip components 8 and 12 also enter the window 13. For this reason,
Even if an attempt is made to recognize the chip component 6, since the shadow 5a is missing, the shadow 7b of the chip component 8 will be mistakenly recognized.

(Problems to be Solved by the Invention) As described above, the light cutting method and the pattern comparison method take a long time to inspect, and the oblique light and shadow method requires chip parts to be mounted adjacent to each other, or the surface condition of the circuit board. Shadow information of chip components is missing, resulting in erroneous recognition of shadows of adjacent chip components.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a mounting state recognition device that can recognize the mounting state of chip components at high speed without being affected by the fact that chip components are mounted adjacent to each other or the surface condition of a circuit board. .

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a mounting state recognition device that recognizes the mounting state of components mounted on a board, which is disposed diagonally above the board to create shadows of the components. an imaging device that is placed above the board to capture images of multiple components mounted on the board within the same field of view, and a shadow of each component obtained by imaging with this imaging device. The above object is achieved by providing a recognition means that recognizes the mounting state of each component from the shadow image data, sets a recognition area for the shadow of the unrecognized component based on the position of the shadow of the recognized component, and performs re-recognition. It is a mounting status recognition device that attempts to

(Function) By providing such a means, light is irradiated onto the board from the illumination device disposed diagonally above the board to create shadows on each component, and these components and their shadows are imaged by the imaging device. The recognition means recognizes the mounting state of each component from shadow image data including shadow data of each component obtained by imaging with this imaging device. If there is a component that is not recognized by this recognition means, a recognition area for the shadow data of the unrecognized component is set based on the position of the shadow data of the recognized component, and the recognition is re-recognized.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram of a mounting state recognition device.

A circuit board 23 on which a wiring pattern 21 is formed and chip components 22 are mounted is placed on the XY table 20. This XY table 20 is configured to move on the XY plane in response to a drive signal from an xY table drive circuit 24.

On the other hand, a first illumination device 25 and a second illumination device 26 for oblique light shadow images are arranged diagonally above the circuit board 23 and facing each other with the circuit board 23 interposed therebetween. These first and second lighting devices 25 and 26 are adapted to be turned on separately in response to switching signals from the lighting switching circuit 27.

Further, an imaging device 28 is arranged almost directly above the circuit board 23 to take an image of the circuit board 23 and output an image signal thereof. The output terminal of this imaging device 28 has an A/
The image memories 31 and 32 of the image processing device 30 are commonly connected via the D conversion circuit 29. These image memories 31 and 32 receive timing signals from the timing circuit 33 and store digital image signals from the A/D conversion circuit 29.
The image memory 32 receives the digital image signal when 5 is lit and stores it as oblique light and shadow image data.
A digital image signal when the illumination device 26 is turned on is received and stored as oblique light and shadow image data.

The image processing device 30 performs image processing on each shade image data stored in each image memory 31 and 32 to form a chip component 22.
It has the function of recognizing the wearing state of the device, and has the following structure. A subtraction circuit 34 is connected to each image memory 31, 32, and a binarization circuit 35 is connected to its output terminal. A projection circuit 37 is connected to this binarization circuit 35 via an image memory 36. This projection circuit 37 sets a window in the portion of the shading data of the chip component for the binarized image data stored in the image memory 36, and performs a projection process on the binarized image data in the X direction and the y direction. It has a function of obtaining each projection data by integrating each level. An arithmetic control circuit 38 is connected to this projection circuit 37, and this arithmetic control circuit 38 determines the edge position of the chip component 11 from each projection data obtained by the projection circuit and determines the mounting state of the chip component 11, that is, the chip component. It has a function of determining the center coordinates of 22 and storing them in the coordinate storage circuit 39. Further, this arithmetic control circuit 38 deletes the shadow data of the recognized chip components to create image data containing only the shadow data of the unrecognized chip components, and sends this image data again to the projection circuit 37 for projection processing. It has a function to perform re-recognition operation. In addition to the above-mentioned functions, the arithmetic control circuit 38 also has a function of issuing operation commands to the XY table drive circuit 24, illumination switching circuit 27, and timing circuit 33 to control recognition operations, and also controls the mounting of the chip component 22. It has a function of displaying the status recognition result on the display circuit 40. Note that the subtraction circuit 34 and the binarization circuit 35 operate upon receiving a timing signal from the timing circuit 33.

Next, the operation of the apparatus configured as described above will be explained.

Only the first lighting device 25 is turned on by the switching operation of the lighting switching circuit 27. In this state, the imaging device 28 images the circuit board 23 with an imaging field including a plurality of chip components 22 and outputs the image signal. This image signal is A-
It is converted into a digital image signal by two D conversion circuits and sent to each image memory 31, 32. At this time, since the first lighting device 25 is turned on, the digital image signal is stored in the image memory 31 as oblique light and shadow image data in response to a timing signal from the timing circuit 33.

Next, the lighting switching circuit 2
7, the first lighting device 25 is turned off and the second lighting device 26 is turned on. The imaging device 28 images the circuit board 23 again and outputs the image signal, and this image signal is sent to the A-D conversion circuit 2.
Each image memory 31 is converted into a digital image signal by
．． Sent to 32. At this time, the digital image signal is
Since the second lighting device 26 is lit, the timing circuit 3
3 is stored in the image memory 32 as oblique light and shadow image data.

In this way, each oblique light and shadow image data is stored in each image memory 31.
32, the subtraction circuit 34 reads out the oblique light and shadow image data from the image memories 31 and 32, respectively, and performs subtraction processing. The results of this subtraction processing are sequentially binarized in the binarization processing circuit 35 and stored in the image memory 36.
It is stored as digitized image data. The m2 diagram is a schematic diagram of binarized image data, and in the same figure, 41a, 4lb
are images of the shadow of the chip component 22-1 caused by light irradiation from the first lighting device 25 and the second lighting device 26, respectively. Similarly, 42a and 42b are the shadows of the chip component 22-2,
43a and 43b are the shadows of the chip component 22-3, .=4
6a and 46b are in the shadow of the chip component 22-6. In this case, each chip component 22-3 and 22-3
-5 shadows 43a and 45b are missing.

Next, the arithmetic control circuit 38 issues an operation command to the projection circuit 37. Upon receiving this operation command, the projection circuit 37 moves the image memory 3
The binarized image data stored in 6 is read out and projection processing is performed in each axis direction of the X axis and the y axis. In this projection process, a window 13 as shown in FIG. 3 is set, and within this window 13, the binarization levels of each pixel are added in each direction of the X-axis and the Y-axis. However, the arithmetic control circuit 38 detects each edge position of each chip component 22-1, 22-2, 22-4, and 22-6 from the result of the projection process, and from these edge positions, the chip component 22-1
, 22-2, 22-4, 22-6 center coordinates 01, 02
, 04, 06, inclination, etc. are recognized and stored in the coordinate storage circuit 39.

Next, the arithmetic control circuit 38 issues a command to the lighting switching circuit 27 again to turn on the first lighting device 25 and the second lighting device 26 separately. Then, the imaging device 28 images the circuit board 23 when each of the first and second lighting devices 25 and 26 is turned on, and outputs the image signal. Thereafter, in the same way as the above operation, each oblique light and shadow image data when each illumination device 25.26 is turned on is stored in the image memory 31.32 and subjected to subtraction processing,
Thereafter, the data is binarized and stored in the image memory 36 as binarized image data.

When the binarized image data is stored in the image memory 36 in this way, the arithmetic control circuit 38 stores each chip component 22-1, 22-2, 22-4,
By reading out the center coordinates 01, 02, 04, 06 of 22-6, each chip component 22-1 that has already been recognized as shown in FIG.
, 22-2, 22-4, and 22-6 are deleted. Fourth
The figure shows these chip parts 22-1, 22-2, 22-4,
22-6 shows the binarized image data after removing the shadow. The projection circuit 37 sets a window 13 for the chip components 22-3 and 22-5 that were not recognized in the above-mentioned recognition operation in this binary image data, and executes a projection process. However, the arithmetic control circuit 38 detects each edge position of each chip component 22-3, 22-5 from the result of the projection process, and detects the edge position of each chip component 22-3, 22-5 from these edge positions.
22-5 center coordinates 03, o, and inclination are recognized.

In this way, in the above embodiment, light is irradiated from diagonally above the circuit board 23 to create a shadow on each chip component 22, and the shadow of each chip component 22 is imaged by the imaging device 28. The mounting state of each chip component 22 is recognized from the image data, and if there is a chip component that is not recognized at this time, the shadow of the recognized chip component is deleted, a window 13 is set for the shadow of the unrecognized chip component, and the process is performed again. Since the recognition operation has been made, each chip component 22
Even if the chip components 22 are adjacent to each other, the outline image of each chip component 22 can be reliably extracted without being affected by the shadows of these chip components 22, and the outline image of each chip component 22 can be extracted without being affected by the surface condition of the wiring pattern 21 of the circuit board 23. The implementation status can be recognized.

Note that the present invention is not limited to the above-mentioned embodiment, and may be modified without departing from the spirit thereof. For example, in the above embodiment, the subtraction process is performed after image data is stored in each of the image memories 31 and 32, but image data is stored in one image memory and this image data is sequentially read out while the image data is stored in the other image memory. Subtraction processing may be performed on the digital image signal. Furthermore, although the image data sent to the projection circuit 37 is subjected to binarization processing, this image data may remain multivalued. Furthermore, the shadow of the recognized chip component is deleted and re-recognized, but the shadow of the chip component is not deleted, but is changed to the shadow of the unrecognized chip component by considering the coordinate position of the recognized chip component. Alternatively, a window 13 may be set for this purpose.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to recognize the mounting state of chip components at high speed without being affected by the surface condition of a circuit board or when chip components are mounted adjacent to each other. A mounting state recognition device can be provided.

[Brief explanation of drawings]

1 to 4 are diagrams for explaining an embodiment of the mounting state recognition device according to the present invention, in which FIG. 1 is a configuration diagram and FIG. 2 is a schematic diagram of binarized image data. , FIG. 3 is a schematic diagram for explaining the effect of removing the shadow of the recognized chip component,
FIG. 4 is a schematic diagram for explaining the effect of re-recognition, and FIG. 5 is a diagram for explaining the prior art. 20...XY table, 22...chip parts, 23
...Circuit board, 24...XY table drive circuit, 2
5... First lighting device, 26... Second lighting device, 27
...Lighting switching circuit, 28...Imaging device, 29...
・A/D conversion circuit, 30... image processing device, 31.3
2... Image memory, 33... Timing circuit, 34
... Subtraction circuit, 35 ... Binarization circuit, 36 ... Image memory, 37 ... Projection circuit, 38 ... Arithmetic control circuit, three ... Coordinate storage circuit, 40 ... display circuit.

Claims (1)

[Claims] A mounting state recognition device that recognizes the mounting state of a component mounted on a board includes: a lighting device disposed diagonally above the board to create a shadow on the component; an imaging device that images a plurality of the components mounted in the same field of view; and recognition of the mounting state of each component from shadow image data including the shadow of each component obtained by imaging with this imaging device. A mounting state recognition device comprising: a recognition means for setting a recognition area for the unrecognized shadow of the component based on the position of the recognized shadow of the component, and re-recognizing the shadow.