JPH0619257B2 - Mounted board inspection device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting board inspection device for inspecting a mounting defect such as a positional deviation of a component mounted on a printed board.

2. Description of the Related Art Conventionally, visual inspections by humans have been used to inspect for defects such as displacement of parts mounted on a printed circuit board, missing parts, and floating. However, as products become smaller and lighter,
The miniaturization and high-density mounting of components on the printed circuit board are progressing even further. In such a situation, it is becoming difficult for a person to keep a very fine component mounting state for a long time while maintaining high inspection accuracy.

Therefore, recently, while automation of inspection is strongly desired, a device for inspecting a positional deviation of parts from a grayscale image from a video camera has been proposed.

The conventional general inspection apparatus is shown in FIG. In FIG. 4, 401 is a printed circuit board, 402 is a component mounted on the printed circuit board 401, 403 is a video camera, 404 is an internal image memory (not shown) by A / D converting a video signal from the video camera 403. Image capturing circuit to store the image in the image), 405 is an edge detecting circuit that detects the edge of the component from the captured image, 40
6 is a corner detection circuit for detecting the corner of the part from the edge information, 407 is a reference data storage memory in which the reference coordinate value of the corner of each part is stored, 408 is a part of the part based on the detected corner coordinates and the reference coordinates. A deviation amount calculation circuit for calculating the deviation amount, 409 is an allowable deviation amount storage memory in which the allowable deviation amount of the component is stored, and 410 is a comparison between the calculated deviation amount and the allowable deviation amount to determine whether the mounting state of the component is good or bad. This is a comparison / judgment circuit for judgment.

The operation will be described below. The video camera 403 captures an image of the component 402 mounted on the printed circuit board 401, and the video signal is A / D converted by the image capturing circuit 404 and captured in the image memory. An edge of the component 402 is detected by the edge detection circuit 405 using the image, and the corner detection circuit 406 is detected from the edge information.
The coordinate value of the corner of the component 402 is detected by. The detected coordinate value of the corner is compared with the reference coordinate value of the component stored in the reference data storage memory 407, and the shift amount calculation circuit 408 calculates the shift amount between the two. Then, the calculated deviation amount from the reference value of the component and the allowable deviation value stored in the allowable deviation amount storage memory 409 are compared by the comparison / determination circuit 410, and the deviation of the component, the missing item, or the like is detected. The quality of the mounting state is determined.

However, in the inspection method as shown in the conventional example, the component is picked up by the video camera 403 and two-dimensional information is used. However, there is a problem in that it is not possible to detect a defect in which the IC is entirely lifted up and mounted, or a foot of the IC is partially lifted up.

Further, in the case of such an inspection, the reference coordinate value of the component is designated in advance, and only the target component is determined, but it may be erroneously mounted at a position other than the mounting position of the component. There is also a problem that it is not possible to inspect for mounting defects.

The present invention has been made in view of the above-mentioned problems, and in addition to inspecting a two-dimensional (plan view) positional deviation on a printed circuit board, it is possible to easily inspect a defect such as a three-dimensional floating of a component. . Furthermore, it is possible to inspect extra components that are erroneously mounted at positions other than the mounting position.

Means for Solving the Problems In order to solve the above problems, a technical solution of the present invention is, firstly, a laser from a laser light source in a mounting inspection apparatus for visually inspecting a mounted state of a printed circuit board on which components are mounted. Laser light scanning means for scanning light on the printed circuit board by a polygon mirror and an fθ lens, and scattered light obtained by reflecting the light from the printed circuit board by the scanning of the laser light are provided between the printed circuit board and the fθ lens. And a scattered light reflecting means for reflecting the light through a polygon mirror of the fθ lens, and a scattered light from the scattered light reflecting means is condensed by a condenser lens on a position detecting element to output a position signal. The height data of the printed circuit board and the components mounted on the printed circuit board are calculated based on the output position detecting means and the position signal from the position detecting means. Image calculation means, a mask storage means for storing mask data for performing a plurality of mask processing of a predetermined arbitrary size on the mounting position of the component and other than the mounting position of the component, and the image calculating means The height data and predetermined reference height data are compared only within the mask data from the mask storage means, and the determination means determines the quality of the mounting state of the component on the printed circuit board.

Secondly, in addition to the first configuration means, in the case of setting a mask other than the mounting position of the component, it is constituted by a mask storage means for setting a mask shape of a grid or stripe of arbitrary size m × n. It was done.

Operation The first aspect of the present invention is to inspect a printed circuit board on which components are mounted on a whole surface with a laser beam and guide scattered light obtained by reflecting the printed circuit board to a position detecting means by a reflection mirror to determine the height on the printed circuit board. The position where the scattered light is condensed on the position detecting element, which changes according to the unevenness of the, is detected, and the height data of the component mounted on the printed board is calculated by the image calculation processing means from the position signal, and the measured height data is calculated. By comparing with the reference height data, it is possible to easily inspect for a two-dimensional (plan view) positional deviation on the printed circuit board and also for a three-dimensional defect such as floating of a component.

Further, by setting a mask on the mounted component and on the substrate other than the mounted component and comparing it with the reference data, it is possible to inspect the unnecessary component other than the mounting position that is erroneously mounted.

Secondly, when the mask is set on the substrate other than the mounted parts, the mask can be easily set by forming an m × n lattice or tripe.

Example Hereinafter, a first example of the present invention will be described with reference to FIG.

FIG. 1 is a block connection diagram showing an embodiment of the mounting board inspection apparatus of the present invention. In FIG. 1, 101 is a printed circuit board, 102 is a component mounted on the printed circuit board 101, 103 is a conveying means for moving the printed circuit board 101, and 104.
Is an arrow indicating the moving direction. 105 is a laser light source, 1
Reference numeral 06 is a laser beam from the laser light source 105, 107 is a polygon mirror, 108 is a reflecting mirror for guiding the laser beam to the polygon mirror 107, 109 is an fθ lens, and 110 is a reflecting mirror. 111
Is a condenser lens, 112 is a position detecting element, 113 is a position detecting element
A position signal from 112, 114 is an image processing means for converting the position signal 113 into height data of a component, 115 is a determination processing means for determining whether or not the mounting state of the component 102 on the printed circuit board 101 is good, 116 Is on the mounting position of the component 102 and the component
The mask storage means stores a plurality of predetermined mask data other than the mounting position of 102.

The operation will be described below.

The printed circuit board 101 on which the component 102 is mounted is provided with a conveying means 10
While moving in the moving direction 104 by 3
The laser beam 106 from 105 is guided to the rotating polygon mirror 107 by using three reflecting mirrors 108, and the polygon mirror 107
And the fθ lens 109 causes the laser light 106 to emit the laser light 106
Irradiate vertically on top. As a result, the laser light 106 is two-dimensionally scanned over the printed circuit board 101.

Scattered light reflected from the printed circuit board 101 by scanning the laser beam 106 is reflected by a reflection mirror 110 provided between the printed circuit board 101, which is an inspection object, and the fθ lens 109, and the fθ lens 109 and the polygon mirror are reflected. The light is condensed on the position detecting element 112 through 107 and further through the condenser lens 111. The position signal 113 from the position detection element 112 is input to the image calculation processing means 114.

The image calculation processing means 114 performs calculation to convert the position signal 113 input at the timing of the synchronization signal into height data of the printed circuit board 101 and the component 102 mounted on the printed circuit board 101, and determines the actually measured height data. Output to the processing means 115. In the determination processing means 115, the measured height data calculated by the image calculation processing means 114 and the predetermined reference height data are compared only within the mask data from the mask storage means 116, and the components on the printed circuit board 101 are compared. The presence / absence of a component other than the mounting state of the component 102 and the mounting position of the component 102 is determined.

By repeating the above operation and sequentially performing it, the entire surface of the printed circuit board 101 can be inspected. It is necessary to perform this series of operations in synchronism with an appropriate signal, but in the case of this embodiment, synchronism is achieved using a synchronism signal that matches the rotation of the polygon mirror 107.

Next, the image calculation processing means 114, the determination processing means 115, and the mask storage means 116 will be described in more detail with reference to FIGS. 2 and 3.

As shown in FIG. 2, the image calculation processing means 114 converts the position signal 113 from the position detection element 112 into a digital signal by the A / D converter 201 and inputs the digital signal to the position calculation circuit 202. In this embodiment, PSDs (position-sensitive detectors; semiconductor position detecting elements) are used as the position detecting elements, and the incident position at which the PSD is incident is that the current flowing through the electrodes at both ends of the element is between the electrodes. It is inversely proportional to the distance between and. The position calculation circuit 202 calculates the height data of the currents I ₁ and I ₂ from both electrodes, which are converted into digital signals, by using the equation (1).
(However, K is a coefficient for normalization.) Height data = K · (I ₁ −I ₂ ) / (I ₁ + I ₂ ) ... (1) Height obtained by the position calculation circuit 202 The height data is temporarily stored in the measured height data storage memory 203 and output to the determination processing means 115.

The determination processing means 115 compares the measured height data from the measured height data storage memory 203 with the reference height data from the reference height data storage memory 206 in the comparison circuit 204 according to the mask data from the mask storage means 116. Then, the difference is output to the determination circuit 205 as comparison data. In the judgment circuit 205,
Based on the comparison data from the comparison circuit 204, the mounting state of the component is determined by the magnitude of the difference.

In the determination of extra components other than mounted components by the determination processing unit 115, the measured height data is compared with the reference height data, and the measured height data in the mask has a large number of pixels or large data. The method of determining by the area of is also one method.

FIG. 3 shows the mask shape of the mask storage means 116, and a concrete example thereof will be described.

FIG. 3 (a) shows an m × n grid-shaped mask set in a place other than the mounted parts, and FIG. 3 (b) shows an m × n striped mask in a place other than the mounted parts. It shows what has been set. That is, FIG. 3 shows the component mask 303 set on the planned mounting position of the component 302 on the printed circuit board 301 and the m × n lattice-shaped mask 305 or the stripe-shaped mask 305 set on a position other than the planned mounting position. .

EFFECTS OF THE INVENTION As described above, the effects of the present invention are that the height data of the component on the printed circuit board is measured and the reference height is set only in the mask set on the mounting position of the component and other than the mounting position of the component. By comparing with the data and determining the mounting state of the component, it is possible to inspect defects such as three-dimensional component floating that could not be inspected with two-dimensional position information without relying on human visual inspection. As a result, the automation of the inspection can be promoted and the effect is great. By setting a mask at a place other than the position of the mounted component and inspecting it, it is possible to inspect the extra components that are mistakenly attached due to a mounting error.

Also, when setting the mask other than the mounting component position, m ×
It can be easily set by using an n-shaped lattice or stripe mask.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block connection diagram of a mounting board inspection apparatus according to a first embodiment of the present invention, FIG. 2 is a detailed block connection diagram of essential parts of FIG. 1, and FIG. A plan view showing the mask shape in the figure,
FIG. 4 is a block connection diagram of a conventional board inspection apparatus. 101 ... Printed circuit board, 102 ... Parts, 103 ... Conveying means, 105 ... Laser light source, 107 ... Polygon mirror, 109
...... fθ lens, 110 …… reflection mirror, 111 …… condensing lens, 112 …… position detection element, 114 …… image calculation processing means,
115 ... Judgment processing means, 116 ... Mask storage means.

 ─────────────────────────────────────────────────── ─── Continued front page (72) Yufumi Tsuda Inventor Yukifumi Tsuda 3-10-1 Higashisanda, Tama-ku, Kawasaki City, Kanagawa Matsushita Giken Co., Ltd. No. 3 No. 1 Matsushita Communication Industrial Co., Ltd.

Claims (2)

[Claims] 1. A conveyance means for moving a printed circuit board on which components are mounted, a laser light scanning means for scanning the laser light from a laser light source on the printed circuit board by a polygon mirror and an fθ lens, and scanning of the laser light. Scattered light reflecting means for reflecting scattered light obtained by being reflected from the printed circuit board by means of a reflection mirror provided between the printed circuit board and the fθ lens, and reflected through the fθ lens and a polygon mirror. Position detecting means for collecting the scattered light from the scattered light reflecting means on a position detecting element by a condenser lens and outputting a position signal, and the printed circuit board and the printed circuit board mounted by the position signal from the position detecting means. Image calculation means for calculating the height data of the component, and a plurality of predetermined sizes on the component mounting position and other than the component mounting position. Mask storage means for storing mask data to be processed, and height data calculated by the image calculation means and predetermined reference height data are compared only within the mask data from the mask storage means, and the print is performed. A mounting board inspection device, comprising: a judgment processing means for judging whether or not the mounting state of a component on the board is good. 2. The mask storage means, when setting a mask other than the mounting position of a component, sets the mask shape in a grid or stripe shape with an arbitrary size of m × n. Mounted board inspection device.