JPH02151702A - Apparatus for inspecting mounting of part - Google Patents

Abstract

PURPOSE:To detect a mounting position regardless of the height of a mounting part by projecting slit patterns having a plurality of colors different alternately from each other on a printed circuit board and imaging the slit patterns individually through filters of respective colors. CONSTITUTION:A color multislit light source 1 is constituted so that a slit plate 1b having a plurality of slits alternately masked with red and blue filters and a shutter 1c are mounted to the light emitting port of a light source 1a and arranged at a place diagonally above a printed circuit board 3 to project red and blue lights on the substrate 3 in an X-axis direction. Then, a color filter 15 is rotationally driven by a rotary actuator 14 to take the image of the slit pattern on the substrate 3 by a camera 6 through the red filter and, next, in the same way, the image of the blue slit pattern on the substrate 3 is taken by the camera 6 through the blue filter. At this time, even in such a case that the adjacent slit patterns are overlapped on the surface of a part 4 and that of the substrate 3, since the surface colors of the part and the substrate are different, the discontinuity of the edge part of the part 4 can be easily detected. With respect to a Y-axis direction, the same operation is performed using a light source 2.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a component mounting inspection device for inspecting the mounting state of electronic components mounted on a printed circuit board.

<Prior Art> Conventionally, when chip parts such as ICs, capacitors, and resistors, and irregularly shaped parts such as volumetric parts are incorporated into various electronic devices, this is usually done by mounting them on a printed circuit board on which wiring is formed. By the way, in order for these electronic devices to operate normally, it goes without saying that each mounted component must be of good quality, but even if each mounted component is of good quality, it is difficult to place them in their designated positions on the printed circuit board. must be installed correctly. Therefore, during assembly, the mounting state of the mounted components on the printed circuit board is inspected.

In the conventional component mounting inspection method, as shown in FIG. 8, when monochromatic slit light is projected obliquely from above onto a printed circuit board 3 on which an electronic component 4 is mounted, the top surface of the mounted component 4 is raised from the surface of the printed circuit board 3. Since it is located at the height H, the slit pattern when the printed circuit board 3 is viewed from the vertical direction becomes discontinuous at the edge portion of the three-dimensional mounted component 4, as shown in FIGS. 9 and 10. This slit pattern is imaged, and the mounting position of the component is detected from the discontinuous position of the slit pattern in this ↑ most imaged image data. Then, if the detected position is within the error range, it is determined to be "good", and if it is outside the error range, it is determined to be "fail".

<Problem that the invention seeks to solve> The drawbacks of the conventional inspection method described above are as follows.

As shown in FIG. 8, if the incident angle of the slit light with respect to the printed circuit board 3 is α, and the interval between the slit patterns is S, then when the height H of the mounted component 4 satisfies H=S-tan α, As shown in FIGS. 11 and 12, the slit pattern Pl on the surface of the mounted component 4 and the surface of the printed circuit board 3 is formed by adjacent slit lights.

P2 overlaps. Therefore, the edges of the mounted component 4 cannot be detected. As described above, there has been a problem in the past in that the mounting position cannot be inspected depending on the height of the mounted component.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a component mounting inspection device that can detect the mounting position regardless of the height of the mounted component.

Means for Solving the Problems> In order to achieve the above object, a component mounting inspection device according to the present invention diagonally directs slit lights of a plurality of different colors alternately onto a printed circuit board on which electronic components are mounted. slit pattern projection means for forming a slit pattern by projecting it onto the printed circuit board; and detection means for detecting the mounting position of the component.

In the component mounting inspection device according to the present invention, slit lights of multiple colors are projected from an oblique direction to form a slit pattern on a printed circuit board in which adjacent patterns have different colors, and the slit light is passed through a filter of each color. Image the slit patterns individually. Therefore, even if adjacent slit patterns overlap on the component surface and the substrate surface depending on the height of the mounted component, the slit pattern of the captured image data becomes discontinuous at the edge portion of the mounted component.

<Embodiment> FIG. 1 shows the configuration of an embodiment of this component mounting inspection apparatus. In the figure, 1.2 is a color multi-slit light source, 3 is a printed circuit board, 4 is a chip component, 5 is an X-Y table, 6 is a camera, 7 is an A/D conversion unit, 8 is an image processing unit, and 9 is a control unit. part, 10 is an X-Y table drive circuit, 11
12 is an X-axis direction drive section, 12 is a Y-axis direction drive section, 13 is a filter switching circuit, 14 is a rotation actuator, and 15 is a color filter.

The two color multi-slit light sources 1 and 2 are arranged diagonally above the printed circuit board 3 on the XY table 5, and project red and blue slit lights onto the printed circuit board 3. The color multi-slit light source 1 projects slit light in the X-axis direction, and the color multi-slit light source 2 projects slit light in the Y-axis direction. A color multi-slit light source 1 includes a slit plate 1b and a shutter IC attached to a light irradiation port of a light source 1a. The color multi-slit light source 2 has a slit plate 2b and a shutter 2c attached to the light irradiation port of the light source 2a. Each of the slit plates 1b and 2b has a plurality of slits, and each slit is masked alternately with red and blue filters. Shutter lc, 2c
are alternately opened and closed in order to individually project the slit lights in the X-axis direction and the Y-axis direction onto the printed circuit board 3.

A large number of chip components 4 are mounted on the printed circuit board 3, and the mounting positions of these chip components 4 are to be inspected. X-
The Y table 5 has the printed circuit board 3 placed thereon in the X-axis direction and the Y-axis direction.
Move in the axial direction. The camera 6 images the color multi-slit pattern formed on the printed circuit board 3 through the color filter 15. This camera 6 is a black and white CCD
It's a camera.

The A/D converter 7 converts an image signal output from the camera 6 that captures an image of the slit pattern on the printed circuit board 3 into digital data. The image processing unit 8 detects discontinuity in the slit pattern in the captured image, detects the mounting position of the chip component 4 on the printed circuit board 3, and determines whether the mounting position of the chip component 4 is within the error range. do.

The control unit 9 sends a command signal to move the X-Y table 5 so that the next inspection range of the printed circuit board 3 falls within the imaging range of the camera 6 upon completion of the detection and determination processing in the image processing unit 8. is applied to the XY table drive circuit 10.

The X-Y table drive circuit 10 provides drive signals to the X-axis direction drive section 11 and the Y-axis direction drive section 12 according to the moving distances in the X-axis direction and the Y-axis direction. The X-axis direction drive section 11 and the Y-axis direction drive section 12 drive the X-Y table 5 in the X-axis direction and the Y-axis direction according to drive signals given to each of them.

The filter switching circuit 13 outputs a signal for selecting a color filter of a predetermined color from among the color filters 15 in response to a control signal from the control section 9 .

The rotation actuator 14 rotates a plurality of color filters 1.
The color filters 15 are rotated so that a desired color filter from among the color filters 5 is placed in front of the lens of the camera 6. The color filter 15 is composed of a color filter having the same characteristics as the color filter attached to the slit plates 1b, 2b of the color multi-slit light source 1.2.

The operation of this component mounting inspection device will be explained below.

First, the XY table 5 is driven so that the first inspection range of the printed circuit board 3 falls within the imaging range of the camera 6, and the printed circuit board 3 is positioned. Then, (1) the shutter IC is opened and red and blue slit lights are projected onto the printed circuit board 3 in the X-axis direction;

■ The rotary actuator 14 rotates the color filter 15 in response to a signal from the filter switching circuit 13,
Position the red color filter in front of the lens of the camera 6.

(2) The slit pattern on the printed circuit board 3 is imaged by the camera 6 through a red filter. In this case, since the image is captured through a red filter, the slit pattern imaged by the camera 6 is only the red pattern, and the blue pattern is not imaged.

(2) The image data captured by the camera 6 is converted into digital data by the A/D converter 7 and stored in the red (X) image memory in the image processor 8.

(2) Position the blue filter of the color filter 15 in front of the lens of the camera 6 in the same manner as (2).

■ Image the blue slit pattern in the same manner as in ■.

■ The blue image data is transferred to the image processing unit 8 in the same manner as in ■.
The image is stored in the blue (X) image memory within the blue (X) image memory.

(2) Next, the shutter IC is closed, the shutter 2C is opened, and the slit light in the Y-axis direction is projected onto the printed circuit board 3.

(2) The slit pattern image in the Y-axis direction is stored in the red (Y) image memory and the blue (Y) image memory in the image processing section 8 using the same procedure as (2) to (2).

The image signal input through the above procedure is based on the shape of the chip component 4 because the chip component 4 has a three-dimensional shape on the printed circuit board 3 and the linear slit light is projected from an oblique direction. The slit pattern changes accordingly, and becomes discontinuous with the slit pattern on the surface of the printed circuit board 3, especially at the outer edge of the chip component 4. Therefore, the image processing unit 8 can detect the mounting position of the chip component 4 by detecting the discontinuous portion of the slit pattern, and can determine whether the position is within the permissible range.

Depending on the height of the chip component 4 from the surface of the printed circuit board 3, the slit pattern on the surface of the chip component 4 and the slit pattern on the surface of the printed circuit board 30 may overlap in adjacent slit patterns. However, as described above, adjacent slit patterns have different colors, so although the positions of the slit patterns overlap, the colors on the surface of the chip component 4 and the surface of the printed circuit board 3 are different. Figure 2 shows this state, where adjacent slit patterns P
Although the positions of I and P2 match, the red color of slit pattern P1 (indicated by a white background in the figure) and the blue color of slit pattern P2 (indicated by diagonal lines in the figure) are discontinuous at the edge part of the chip component 4. ing.

FIG. 3 shows an example of a slit pattern in the Y-axis direction.

If the slit patterns shown in Figs. 2 and 3 are imaged with a black and white camera without passing through a filter, the color change cannot be captured, and the slit patterns Pi and P2 on the chip component 4 and the printed substrate Fig are It becomes continuous,
The position of the chip component 4 cannot be detected.

However, if a red color filter is placed in front of the lens of the camera 6 to take an image as described above, only the red slit pattern will be imaged, so the imaged slit pattern will be at the edge of the chip component 4 as shown in FIG. becomes discontinuous. Furthermore, if a blue color filter is placed in front of the lens of the camera 6 and an image is taken, only the blue slit pattern is imaged, so the imaged slit pattern is discontinuous at the edge part of the chip component 4, as shown in FIG. Become.

6 and 7 show slit pattern data in the Y-axis direction.

The image memory in the image processing section 8 stores slit pattern data shown in FIGS. 4 to 7. Therefore, the image processing unit 8 can detect the mounting position of the chip component 4 from the discontinuous portion of this slit pattern, and can determine whether the position is within the permissible range. The slit pattern data processed in this image processing section 8 is the same as the pattern created by conventional monochromatic slit light. Therefore, the conventional processing algorithm can be used as is.

By repeating the above-described steps of moving the X-Y table 5, projecting the slit pattern, taking an image, and processing the image, the mounting positions of the chip components 4 can be inspected over the entire printed circuit board 3.

In addition, in the case of a tall deep component in which two or more slit patterns on the surface of the chip component 4 and the surface of the printed circuit board 3 are shifted and overlap, a slit plate with filters of three or more colors is used to By changing the color filter to correspond to the filter of this slit plate,
The position of chip components can be detected using a similar principle.

In addition, in the above embodiment, a shutter is used to project the slit lines in the X-axis direction and the Y-axis direction separately, but instead of this shutter, a strobe or switch is used in the light source section only when necessary. A method of emitting light may also be used. Furthermore, in the above embodiment, the imaging camera was placed at one location, but by forming a slit pattern on the entire surface of the printed circuit board at once, dividing it into a plurality of sections, and providing a camera for each section, the X- It is also possible to perform the inspection with the Y table fixed.

<Effects of the Invention> As described above, according to the present invention, slit patterns in which adjacent patterns have different colors are projected, and the slit patterns are individually imaged through filters of each color. Even for electronic components whose height is such that the patterns overlap, the imaged patterns are discontinuous at the edges of the electronic components, making it possible to detect the mounting position. Further, since the image processing algorithm for detecting the mounting position of the electronic component from the discontinuity of the pattern is the same as that for the conventional monochromatic slit pattern, the system construction is easy.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention, FIGS. 2 and 3 are diagrams showing a slit pattern of an embodiment of the present invention, and FIGS. A diagram showing an imaged slit pattern of an embodiment of the invention, FIG. 8 is a diagram explaining a method of projecting slit light, and FIGS. 9, 10, 11, and 12 show slit patterns of conventional examples. It is a diagram. 1.2... Color multi-slit light source 3... Printed circuit board 4... Chip component 6... Camera 8... Image processing unit 15... Color filter patent applicant Sharp Corporation Agent Patent attorney Nishi 1) New diagram 1

Claims (1)

[Claims] A slit pattern projection means for forming a slit pattern by alternately projecting slit lights of a plurality of different colors from an oblique direction onto a printed circuit board on which electronic components are mounted; A component mounting inspection device comprising: an imaging means for individually capturing images through the plurality of color filters; and a detection means for detecting a mounting position of an electronic component from discontinuity of the captured slit pattern.