JPH0399251A - Mounted state recognizing apparatus - Google Patents

Abstract

PURPOSE:To recognize chip parts mounted on a board at a high speed by producing an image signal of a shaded image of parts obtained with one pair of lighting devices arranged askew above and an image signal of a transmission image given by a lighting from below a substrate. CONSTITUTION:A lighting device 14 is lighted with a switching circuit 17 to take a circuit substrate 12 with a camera 18 and the resulting image signal is stored into image memories 21-23 via an A/D conversion circuit 19. Then, by a command of a control circuit 30, the device 14 is put off with the circuit 17 and a lighting device 15 is lighted to take the substrate 12 with the device 18 and the resulting image signal is stored into memories 21-23 via the circuit 19. Then, the device 15 is put off with the circuit 17 and a lighting device 16 is lighted to take the substrate with the device 18 and the resulting image signal is stored into the memories 21-23 via the circuit 19. A subtraction circuit 25 reads out image data from the memories 21 and 22 to subtract and a subtraction data is sent to an addition circuit 26 to be added to an transmission image data of the memory 26 to be stored into the image memory 28 via a binary coding processing circuit 27. A projection processing of the results is performed with a projection circuit 29 to recognize a mounted state of a chip part 11 with the circuit 30.

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. finish. However, in such mounting, chip components often fall off or become misaligned, and if this is detected after soldering is completed,
That repair. You really have to put in a lot of effort. 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 each direction facing each other through the circuit board, and shadow information of the chip components is obtained from the difference in image data when these lights are irradiated. This is a technology that extracts and inspects the condition of chip components. For example, Fig. 8 shows image data when the circuit board is irradiated with light from direction A, and in this image data, the gray level of the section x-x'' is as shown in Fig. 9. The part with no shadow on the knob part is the brightest, followed by the part with a shadow on the circuit board, and the part with a shadow on the wiring pattern is the darkest.Also, although not shown, the light from direction B is the brightest. Image data is obtained when the light is irradiated onto the circuit board, and data on the shadow of the chip component is extracted from the difference between these image data.

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 shading method enables high-speed inspection by using the shadow information of chip components, the shadow information of the chip components may be missing due to the chip components being mounted adjacent to each other or the surface condition of the circuit board. There is.

For example, when the chip components 2 and 3 are mounted adjacent to each other on the circuit board 1 as shown in FIG.
When light is irradiated from D, shadow information between each chip component 2 and 3 is lost as shown in FIG. In addition, as shown in Figures 8 and 9 above, when there is only a slight difference in brightness between areas with and without shadows on the circuit board, shadow information may not be extracted and may be missing. be.

(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 parts may be missing.

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 parts to be inspected mounted on a board. a third lighting device located below the board; a lighting switching means for separately lighting the first to third lighting devices; and a lighting switch located above the board. An imaging device disposed in the chip component 1 to take an image of this board, image signals of oblique light and shadow images from the imaging device when the first and second lighting devices are respectively turned on by the lighting switching means, and a third lighting device are also connected to the chip component 1.
The implementation status of 1 can be recognized. That is, in the oblique light shadow image data D+ and DI, the shadow portion on the wiring pattern clearly appears, and in the transparent image data D, light does not pass through the chip component 11 and the wiring pattern portion, but light does not pass through the circuit board 12 portion. is transmitted. Therefore, these oblique light and shadow image data D
.
It is possible to reliably extract the outline image of the chip component 1 and to extract the outline image of the chip component 1 without being affected by the surface condition of the wiring pattern of the circuit board 12.
The implementation status of 1 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 embodiment described above, subtraction processing is performed after image data is stored in each of the image memories 21 and 22, but while image data is stored in one image memory and sequentially read out, the image data is Subtraction processing may be performed on the digital image signal, or the oblique light and shadow image data and the transmission image data are added and then binarized, but the oblique light and shadow image data and the transmission image data are each binarized. The addition process may be performed after processing. Furthermore, an image memory may be connected to the output terminal of the subtraction circuit 25 to temporarily store the subtraction image data, and then the subtraction image data may be sent to the addition circuit 26.

Further, although the image data sent to the projection circuit is subjected to binarization processing, this image data may remain multivalued.

[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 7 are diagrams for explaining an embodiment of the mounting state recognition device according to the present invention, in which FIG. 1 is a composition diagram, and FIGS. 2 and 3 are oblique light and shadow image data. 4 is a schematic diagram of transparent image data, FIG. 5 is a schematic diagram of subtraction image data, FIG. 6 is a schematic diagram of addition image data, and FIG. 7 is a diagram for explaining projection processing. FIG. 8 to FIG. 11 are diagrams for explaining the prior art. 10...XY table, 11...chip parts, 12
...Circuit board, 13...XY table drive circuit, 1
4... First lighting device, 15... Second lighting device, 16
...Third lighting device, 17...Lighting switching circuit, 18
...Imaging device, 19...A/D conversion circuit, 20...
・Recognition unit, 21, 22. 23... Image memory, 24.
...Timing circuit, 25...Subtraction circuit, 26...
Addition circuit, 27... Binarization circuit, 28... Image memory, two... Projection circuit, 30... Arithmetic control circuit, 3
1...Display circuit.

Claims (1)

[Claims] A mounting state recognition device that recognizes a mounting state of a component to be inspected mounted on a board, comprising: first and second lighting devices disposed diagonally above the board and facing each other with the board interposed therebetween; a third lighting device disposed below the substrate; a lighting switching device for turning on each of the first to third lighting devices separately; an imaging device disposed above the substrate for capturing an image of the substrate; Each image signal of an oblique light shadow image from the imaging device when the first and second lighting devices are each turned on by the lighting switching means, and a transmitted image from the imaging device when the third lighting device is turned on. 1. A mounting state recognition apparatus, comprising: recognition means for receiving the image signals of the oblique light and shadow image data and the transmission image and performing image processing to recognize the mounting state of the component to be inspected.