JPS62265508A - Inspecting device for package of parts - Google Patents

Abstract

PURPOSE:To inspect the package of parts at a high speed by photographing the parts mounted on a printed circuit board and comparing the number of picture elements of each step width of the image with a reference value for inspection at intervals of step width. CONSTITUTION:The image in the visual field 6a of a television camera 6 is supplied to a fast image processor 10 through a CPU 4 and divided into many picture elements. Those picture elements are sectioned by plural-step width according to density level and stored as the reference value in the CPU 4. Then, the inspected value of the number of picture elements sectioned by the step width of the image obtained by photographing the chip parts 1 mounted on the printed circuit board 2 is compared with the corresponding reference value by the CPU 4, step by step, to decide whether or not the parts 1 is arranged at a correct position.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a component mounting inspection device for determining whether components mounted on a printed circuit board are placed in correct positions.

(Prior Art) A block circuit diagram of a conventional component mounting inspection device is shown in FIG. In FIG. 5, a printed circuit board 2 on which a chip component 1 is mounted is placed on an X-Y table 3.
Table 3 is the central arithmetic processing unit (hereinafter referred to as CPU) 4
The position is controlled by the X-Y table controller 5 based on the signal. Further, above the XY table 3, there is provided a television camera 6 for photographing the chip component 1, and a pair of lamps 7.8 for illuminating the chip component 1 from different directions diagonally above.

These lamps 7 and 8 are turned on at different times by an irradiation power source 9 controlled by the CPU 4, and when each lamp is turned on, a photograph is taken by the television camera 6 and the lighting is performed. Furthermore, the image of the television camera 6 is provided to the high-speed image processing device 10 via the CPU 4 and processed appropriately, and the data is provided to the CPU 4. Further, an image is provided from the CPU 4 to the monitor television 11.

In this configuration, first, by lighting one of the lamps 7 and 8, the television camera 6 is illuminated with light from one side.
As shown in Figure 6, it is formed on the chip component 1 and the opposite side.
ls 1 a and ii. Next, the television camera 6 is illuminated by the lighting of the other lamp 7.8.
As shown in Figure 7, F formed on chip component 1 and its opposite side.
1 b and 11! shadow Then, the two images of the two layers are combined by the high-speed image processing device 10 as shown in FIG.
Shadow 1a.

The vertical dimension 11 and the horizontal dimension I1.2 of the chip component 1 are estimated from 1b to determine if there is an error in the component, and the CPU 4 determines whether the mounting position is accurate.

(Problems to be Solved by the Invention) By the way, the above-mentioned conventional component mounting inspection device is excellent in that it can automate visual component mounting inspection, but this component mounting inspection device has two
Time is required to combine the two images and perform predetermined calculations, and inspection time of 0.2 to 0.3 seconds is required to inspect one chip component 1. The problem of slow speed was solved. Also, a shadow 1a of the chip component 1.

Since the dimensions and positional deviation of chip component 1 are determined from 1b, if chip component 1 is black, chip component 1 and shadow 1a are
There was a problem that inspection was not possible because it was not possible to distinguish between , lb and lb.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the conventional component mounting inspection apparatus described above, and to provide a component mounting inspection apparatus that can perform inspections quickly.

(Means for Solving the Problems) In order to achieve the above object, the component mounting inspection device of the present invention uses an image processing device to capture an image of a component placed at a precise position on a printed circuit board using a television camera. The parts mounted on the printed circuit board are divided into a large number of pixels and divided into multiple step widths based on the gray level, and the number of pixels of each step width is stored as a reference value in the central processing unit. The image photographed is divided into the plurality of pixels and divided into the plurality of step widths based on the density level, and the number of pixels of each step width is used as an inspection value and compared with the reference value for each step width to determine the part. The central processing unit is configured to determine whether or not the image is placed in the correct position.

(Function) An image taken of a component placed at a precise position on a printed circuit board is divided into a large number of pixels, divided into multiple step widths based on gray level, and the number of pixels in each step width is used as a reference value. The number of pixels in each step width of an image taken of a component mounted on a printed circuit board is compared with the reference value for each step width as an inspection value, so if the mounted component is not placed in the correct position, the image will be The inspection value for each step width differs from the reference value due to the change, and it can be determined whether the mounted component is placed in the correct position with a single Ik shadow, and inspection can be performed faster than before. can. Furthermore, since the inspection is performed based on the shading of the image, the inspection can be performed regardless of the color of the part. Furthermore, it is possible to detect the presence of foreign parts of different colors.

(Description of Embodiments) Embodiments of the present invention will be described below with reference to FIGS. 1 to 4. FIG. 1 is a block circuit diagram of an embodiment of the component mounting inspection apparatus of the present invention, and FIG. 2 is an example of an image taken of a chip component placed at an accurate position on a printed circuit board. Figure 3 is an example of an image taken of a chip component placed with a misalignment, and Figure 4 is a diagram showing an example of the ratio of change in the number of pixels in each step width due to the misalignment of the chip component. . In FIG. 1, circuit blocks that are the same as those in FIG. 5 are given the same reference numerals and redundant explanations will be omitted.

In FIG. 1, lamps 7.8 provided above the X-Y table 3 for illuminating the chip component 1 are simultaneously turned on by the illumination power source 12. Kowara's X-Y Table 3
A television camera 6, lamps 7, 8, etc. are installed in the dark room +3. The image within the field of view 6a of the television camera 6 is then provided to the high-speed image processing device IO via the CPU 4, where it is divided into a large number of pixels, and these pixels are divided into a plurality of step widths according to the gray level. For example, as shown in FIG. 2, an image taken of the correctly placed chip component 1 shows the brown color of the main body IC of the chip component 1, and the terminal portion 1d.
The pattern 2a of the printed circuit board 2 has a copper color, the resist portion 2b has a green color, and the like.

Then, one image is divided into a large number of pixels, and multiple step widths are determined depending on the gray level (for example, gray level 0 to 255 is divided into 1
The number of pixels divided into steps (divided into step widths of 0) is configured at a certain rate. Therefore, the number of pixels divided into each step width is stored in the CPU 4 as a reference value.

Then, the chip component 1 mounted on the printed circuit board 2 is photographed with a television camera 6. Here, chip component 1 is
If they are arranged in a shifted position as shown in FIG. 3, the area ratio of the constituent colors of the image within the visual field 6a will be different from the area ratio in FIG. 2. The number of pixels divided into a large number of pixels and divided into a plurality of step widths depending on the gray level is also different from the ratio shown in FIG. 2. It should be noted that the proportions also differ for different types of chip components with different colors.

Therefore, the CPU 4 compares and calculates the inspection value of the number of pixels in which the image of the chip component 1 mounted on the printed circuit board 2 is divided into each step width with the stored reference value.

As this comparison operation, for example, for each step width,
Find the ratio of the difference between the standard value and the test value to the standard value.

Then, as shown in FIG. 4, if there is a step width that exceeds a threshold value of, for example, ±10% in the ratio of each step width, it is determined that the chip component 1 is not placed at the correct position. Note that different types of parts with different colors are also determined to be not placed in the correct position.

Here, even if the chip component 1 is placed at the correct position within the allowable range, there may be uneven color or difference in reflectance of the chip component 1.
Furthermore, due to color unevenness of the printed circuit board 2, etc., the number of pixels divided into each step width tends to shift slightly. In response to such a deviation, if the step width of the reference value is small, (i) due to a change in the inspection value, the ratio of the difference between the reference value and the inspection value to the reference value increases, and the chip component 1
It will be determined that the is not placed in the correct position.

Therefore, if the difference between the reference value and the test value is less than a certain number of pixels, for example less than the discrimination threshold of the number of pixels in the entire image divided by the number of step widths, the ratio will exceed the threshold. Even if it exceeds the threshold, the CPU 4 ignores this and determines the positional deviation of the chip component 1 by comparing the number of pixels for each step width of the gradation distribution only for those above the determination threshold. in this way,
By setting the discrimination threshold, it is possible to improve the judgment ability and improve the stability of the judgment results.

Note that the component to be inspected is not limited to the chip component 1, and may be applied to electronic components such as transistors and ICs. Further, in the above embodiment, the chip component 1 is photographed with the television camera 6 in the dark room 13, but the invention is not limited to this, and by appropriately adjusting the aperture of the television camera 6, the chip component 1 can be photographed in a place other than the dark room 13. Of course, the part 1 may also be photographed.

(Effects of the Invention) As explained above, according to the component mounting inspection device of the present invention, components placed at accurate positions on a printed circuit board can be
The L-shaded image is divided into a large number of pixels and divided into multiple step widths depending on the gray level, and the number of pixels in each step width is used as a reference value, and the components mounted on the printed circuit board are divided into w1.
The number of pixels in each step width of the shaded image is used as an inspection value and compared with the reference value for each step width, so if the mounted component is not placed in the correct position, the inspection value for each step width may change due to a change in the image. Unlike the reference value, it is possible to determine whether a mounted component is placed in the correct position with a single photograph, and inspection can be performed faster than in the past. Furthermore, since the inspection is performed based on the -J5 light of the image, inspection can be performed regardless of the color of the component. moreover,
It has the excellent effect of being able to detect the mixing of different types of parts with different colors.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram of an embodiment of the component mounting inspection apparatus of the present invention, and FIG. 2 is an example of an image taken of a chip component placed at an accurate position X on a printed circuit board. , FIG. 3 is an example of an image taken of a chip component placed with a misalignment, and FIG. 4 is a diagram showing an example of the ratio of change in the number of pixels of each step width due to the misalignment of the chip component. 5 is a block circuit diagram of a conventional component mounting inspection apparatus, FIGS. 6 and 7 are explanatory views of two images taken in FIG. 5, and FIG. 8 is a block circuit diagram of a conventional component mounting inspection apparatus. 7 is an explanatory diagram of an image obtained by combining the two images of FIG. 6 and FIG. 7. 1: Chip parts, 2 Niblint board, 4: CPU, 6: TV camera, 6a: Field of view, 1
0: High-speed image processing device. Patent applicant: Alps Electric Co., Ltd. Representative: Patent attorney: Tetsuo Moriyama

Claims (1)

[Claims] An image of a component placed in a precise position on a printed circuit board is taken by a television camera, and an image processing device divides it into many pixels, divides it into multiple step widths based on the gray level, and calculates the number of pixels in each step width. storing it in a central processing unit as a reference value, and further dividing an image taken by a television camera of the component mounted on the printed circuit board into the plurality of pixels and dividing it into the plurality of step widths depending on the gray level, Component mounting characterized in that the central processing unit determines whether or not the component is placed in the correct position by comparing the number of pixels of each step width as a test value with the reference value for each step width. Inspection equipment.