JPH0814855A - Inspection method for component mounting state - Google Patents

Abstract

PURPOSE:To improve work efficiency for inspecting an electronic component lead, particularly the lead of a deformed component by inspecting the mounting state of the component on the basis of the shade thereof generated due to the irradiation of light toward a printed circuit board along a specific direction. CONSTITUTION:The outlets of through-holes 5 and 6 are irradiated from a light source 7 along a slanting direction, and this light is used to project the shades (or shadows) 8 and 9 of leads 3 and 4 to the reverse side of a printed circuit board 1. Then, each of the shades 8 and 9 is detected to evaluate the proper insertion state of the leads 3 and 4. For example, if the lead 4 fails to be inserted in the through-hole 6 and the leading end thereof does not come out to the reverse side of the board 1, the shade 8 of the lead 3 is formed, but not the shade 9 of the lead 4. The shades 8 and 9 are detected by photographing the outlets of the through-holes 5 and 6 by a CCD camera 10. The photographed image is binarized with an image processing device 11, and the shades 8 and 9 of the leads 3 and 4 are detected on the basis of image data so obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to an inspection machine for inspecting the appearance of irregularly shaped parts mounted on a printed circuit board.
In particular, the present invention relates to a component mounting state inspection method for inspecting whether or not the lead wire of a deformed component is inserted into a through hole provided in a printed board.

[0002]

2. Description of the Related Art Many electric circuits in recent electronic devices are composed of printed circuit boards. The printed circuit board is one in which printed wiring is made of a metal material on the surface of a substrate body made of an insulating material such as plastic.

Generally, in order to mount a component on a printed circuit board, a through hole is provided in the printed circuit board, the component is mounted on the surface not printed, and the terminal or lead wire of the component is passed through the through hole. After it is exposed on the printed wiring side, it is connected to the printed wiring.

The work of inserting the lead wire of the component into the through hole of the printed circuit board is automatically performed by an automatic lead wire inserting machine. That is, the automatic lead wire insertion machine positions the component at a predetermined position above the printed circuit board, presses the component from above after the tip of the lead wire of the component is aligned with each through hole of the printed circuit board. All lead wires are simultaneously inserted into the corresponding through holes by.

When all the parts are standard ICs, for example, rectangular ICs, the lead wires are of pin type, so that the parts are attached by the above-described automatic lead wire inserting machine relatively accurately and easily. You can

However, in the case of a deformed part in which the lead wire is thin and the diameter of the through hole is small, if there is a slight error in the positioning of the part, the tip of the lead wire and the through hole will not match, and therefore When pressed from, the lead wire may be bent at the entrance of the through hole without being inserted into the through hole.

As described above, a component lead inspection is performed in order to find a defective product in which lead wires have failed to be inserted.
This component lead inspection was conducted visually.

[0008]

However, as in the prior art described above, after the lead wire of the component is inserted into the through hole of the printed circuit board by using the automatic lead wire inserting machine, the lead wire is The method of visually inspecting whether or not it completely reaches the back surface of the printed circuit board has the problems that the inspection takes time, the inspection efficiency is poor, and the quality of the printed circuit board deteriorates due to oversight by the inspector. It was

Therefore, there is a problem that must be solved to improve the work efficiency of the component lead inspection of electronic parts, especially odd-shaped parts, and to improve the quality of finished products.

[0010]

In order to solve the above problems, a method of inspecting a component mounting state according to the present invention irradiates a printed board on which a component is mounted with light from a predetermined direction and irradiates from the predetermined direction. That is, the mounting state of the component is inspected from the shadow of the component generated by the light.

Further, the light from the predetermined direction is emitted from an oblique direction; the light from the predetermined direction is
Irradiating the lead wire of the component protruding on the back surface of the printed circuit board; the shadow generated from the printed circuit board mounted on the component is photographed by a CCD camera to be binarized data; The mounted state of the component is inspected by comparing the converted data with a predetermined pattern; the shadow of the component photographed by the CCD camera and the predetermined pattern can be simultaneously displayed; The predetermined pattern is a method of inspecting the component mounting state that is appropriately adjustable.

[0012]

In the inspection method of the component mounting state having the above-mentioned structure, the following operation is achieved.

(1) Since the mounting state of the component is inspected by the shade of the light emitted from the predetermined direction on the printed circuit board on which the component is mounted, the component can be mounted accurately and quickly without directly touching the printed circuit board. You will be able to inspect the condition.

(2) By irradiating the light obliquely, it becomes possible to accurately extract the mounting state of the component due to the shadow.

(3) By irradiating the lead wire of the component with light, it becomes possible to inspect the mounting state of the component with a simple shadow pattern.

(4) The shadow information of the component can be digitally processed by photographing the shadow of the component with the CCD camera and converting it into binary data.

(5) By comparing the shading of the component with a predetermined pattern to inspect the mounting state of the component, even if the component mounted on the printed circuit board is changed, it can be easily changed. It becomes easy to create a pattern corresponding to the mounting state of the attached parts.

(6) By making it possible to simultaneously display the binarized data of the shadows of the parts photographed by the CCD camera and the predetermined pattern at the same time, it is possible to perform an automated inspection and manually compare the shadow states visually. Will be able to do.

(7) By making the predetermined pattern adjustable, fine adjustment of the pattern side can be appropriately performed in the inspection process.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a component mounting state inspection method and its inspection system according to the present invention will be described below.
In addition, the inspection of the component mounting state in the embodiment will be described with respect to an inspection method by a shadow in which the lead wire of the component protruding on the back surface of the printed circuit board is irradiated with light.

The principle of the component lead inspection method according to the present invention is that, as shown in FIG. 1, the lead wires 3 and 4 of the odd-shaped component 2 mounted on the printed circuit board 1 are connected to the through holes 5 formed in the printed circuit board 1. , 6 after the work for inserting the lead wires 3, 4 into the through holes 5, 6 is automatically inspected.

Therefore, the outlets of the through holes 5 and 6 are illuminated by the light source 7 from an oblique direction, and the lead wires 5 and 6 are irradiated by this light.
The shadows (shadows) 8 and 9 of 6 are projected on the back surface of the printed circuit board. The quality of insertion of the lead wire is determined by detecting the shadows 8 and 9 of the lead wires 3 and 4, respectively.

That is, for example, the lead wire 5 is completely inserted into the through hole 3 and the tip of the lead wire 5 is exposed on the back surface of the printed circuit board 1. However, the lead wire 6 fails to be inserted into the through hole 4 and its tip is When it does not appear on the back surface of the printed circuit board 1, the shadow 8 of the lead wire 5 is formed, but the shadow 9 of the lead wire 6 is formed.
Will not be formed.

The CCD camera 10 detects the shadows 8 and 9.
By photographing the exit of the through holes 5 and 6. The image photographed by the CCD camera 10 is binarized by the image processing device 11, and based on the binarized image data (digital data), the shadow 8 of the lead wire,
9 is detected.

The criteria for judging the quality of the lead wire insertion are
The size of shadows 8 and 9 is set. In the image processing apparatus 10, a window serving as a reference for the size of the shadows 8 and 9 of the lead line is set in advance. As the window, a circular region centered on the through hole, a rectangular region extending from the through hole in the direction opposite to the light source 7, a fan-shaped region, or the like can be considered.

The size of the window is such that the length L of the tip of the lead wires 3 and 4 protruding from the surface of the printed circuit board 1 when the lead wires 3 and 4 are completely inserted into the through holes 5 and 6, and the length of light. It depends on the irradiation angle θ. That is, the length W of the shadows 8 and 9 of the lead wires 3 and 4 in the case of complete insertion is Ltan θ.

An embodiment in which the component lead inspection method based on the above principle is applied to the component lead inspection system of the odd-shaped component inspection machine will be described below.

The deformed parts inspection machine 12A according to this embodiment is
As shown in FIG. 2 is a front view of the inside viewed from the front, and FIG. 3 is a side view of the inside viewed from the right side of FIG. 2, the box 12, the loader rail 13, and the monitor camera 14 are shown.
The CCD camera 15, the light source 16, the XY robot 17, the image processing device 18, and the sequencer 19.

The box 12 is the irregular shape component inspection machine 12A.
Outer box of, for example, height about 1250 mm, front width 90
It is composed of a rectangular box having a width of 0 mm and a side width of 1000 mm, and the space therein is vertically divided into three by partition plates 12a and 12b. The loader rail 13 and the monitor camera 14 are accommodated in the upper stage, and the CC is provided in the middle stage.
A D camera 15, a light source 16 and an XY robot 17 are housed, and an image processing device 18 and a sequencer 19 are housed in the lower stage.

In FIG. 2, an automatic lead wire insertion machine (not shown) for inserting lead wires of parts into the through holes of the printed circuit board 1 is installed on the right side of the odd-shaped parts inspection machine 12A. On the left side of the machine 12A, a hopper (not shown) for accommodating the tested and accepted products is installed.

The loader rail 13 is a part of a printed circuit board carrying device which is automatically controlled by the monitor camera 14 and the sequencer 19, and is composed of two rails having an L-shaped cross section. The two rails horizontally penetrate the upper stage of the box 12 in parallel so that their corners face each other, and connect the lead wire automatic inserting machine and the hopper. The loader rail 13 is installed so as to form an endless track that moves in the direction from the automatic lead wire inserting machine to the hopper, and FIG. 2 shows only a part thereof.

The movement and stop of the loader rail 13 are controlled by the monitor camera 14 as a sensor and the sequencer 19 as a controller. When the printed circuit board 1 on which parts are attached by the automatic lead wire insertion machine is placed between the two rails of the loader rail 13 that moves, the printed circuit board 1 is transferred from the automatic lead wire insertion machine to the inside of the irregular component inspection machine 12A. Be delivered to. This variant parts inspection machine 1
The printed circuit board 1 on which the lead wire inspection at 2A is completed is carried out by the loader rail 13 from the irregular shape component inspection machine 12A to the hopper.

What is important in the loader rail 13 is that
When the printed circuit board 1 is placed on it, the lower surface of the printed circuit board 1 is transparent from the middle stage of the box 12. As a result, the lower surface of the printed circuit board 1 is CCD
It can be photographed by the camera 15.

A monitor camera 14 is installed on one side of the upper loader rail 13 of the box 12. The monitor camera 14 has a function of a sensor that detects the printed board 1 placed on the loader rail 13 and carried in, and notifies the sequencer 19 of the printed board 1.

The sequencer 19 is configured to control the printed board carrying device so as to stop the loader rail 13 in response to the printed board detection signal from the monitor camera 14.

CC installed in the middle of the box 12
The D camera 15 is arranged below the loader rail 13 so that the finder faces directly above so that the lower surface of the printed circuit board 1 placed on the loader rail 13 is photographed. The lower end of the CCD camera 15 has an XY robot 1 described later.
It is connected to the driving unit 17b of No. 7 so that it can be freely moved while standing upright and positioned at arbitrary XY coordinates.

The CCD camera 15 has a light receiving surface in which a large number of CCD elements for converting the intensity of light into an electric signal are arranged in a dot matrix. The light from the subject is each CCD
By illuminating the elements at the same time, an image of the subject is formed in the dot matrix in the form of electric signals. The pixels of this image correspond to CCD elements. Each CCD
By scanning the output of the element, a time-series image signal is obtained.

The light source 16 is installed in the middle of the box 12 so as to illuminate the lower surface of the printed circuit board 1 mounted on the loader rail 13 from an oblique direction. The function of this is as described in the principle of the present invention.

The XY robot 17 is installed on the partition plate 12b of the box 12, and has a control unit 17a, a drive unit 17b, a CCD camera holding unit 17c, and a coupling unit 17d.
Consists of The CCD camera holding portion 17c corresponds to the hand of the robot, and holds and holds the CCD camera 15 in an upright state. The CCD camera holding unit 17c is a driving unit 17b.
It is driven freely in the X and Y directions.

The drive unit 17b of the XY robot 17 is operated by X
Direction driving servo motor, Y direction driving servo motor, rotation axes of these motors, and the CCD camera holding unit 1
7c and a coupling mechanism 17d for coupling with 7c. Each motor receives a signal indicating a rotation direction and a rotation amount from the control unit 17a, and rotates according to the signals, thereby CC
The D camera holding portion 17c is moved in the X and Y directions, and as a result, the CCD camera 15 is positioned.

The image processing device 18 subjects the time-series digital image signal generated by scanning the output signal of each CCD element of the CCD camera 15 to predetermined image processing to analyze the required data of the subject. That is,
An analysis is performed to judge whether the lead wire of the component is inserted or not according to the size of the shadow of the lead wire and the window stored in advance.

The output signal of the image processing device 18 is connected to another monitor 20, and the image of the back surface of the printed circuit board 1 taken by the CCD camera 15 is directly displayed on the screen of this monitor 20 as shown in FIG. As shown, a normal screen can be displayed, and an image in which the shadow of the lead wire of the printed circuit board 1 is binarized can be displayed as a binarized screen as shown in FIG.

In FIG. 4 and FIG. 5, an annular one is a printed wiring around the through hole of the printed board 1, and a cut of the ring shows a shadow of the lead wire.

The sequencer 19 is composed of a general personal computer, and has a CPU, a memory, a multi-display, an input device such as a keyboard and a mouse, and a component lead inspection program. By executing the component lead inspection program, the respective operations of the printed circuit board transport device (loader rail 13, monitor camera 14, etc.), the XY robot 17, and the image processing device 18 are controlled to comprehensively control the component lead inspection. To do.

The constituent parts of the irregular-shape component inspection machine 12A, which have been individually described above, are electrically connected as shown in FIG.

The sequencer 19 is an XY robot 17
The control unit 17a is connected to the control unit 17a by connection lines 22 and 23. Sequencer 19 to C via connection line 22
The positioning signal designating the shooting position of the CD camera 15 is X.
-Sent to the control unit 17a of the Y robot 17.

This positioning signal assumes plane coordinates corresponding to the Cartesian coordinates assumed on the printed circuit board 1 on the XY robot 17, and the coordinates of the position which the CCD camera 15 should take on this plane coordinates ( (X, Y). CCD camera 15 at this coordinate (X, Y)
When is positioned, the CCD camera 15 can photograph an area centered on a point (X, Y) on the coordinates of the printed circuit board 1.

Also, a status signal indicating the current status of the XY robot 17 is fed back to the sequencer 19 from the control section 17a of the XY robot 17 via the connection line 23 and used for controlling the sequencer 19. It

The control section 17a and the drive section 17b of the XY robot 17 are connected by a connection line 24.

The controller 17a controls the X motor of the driver 17b based on the positioning signal input from the sequencer 19.
The required rotation direction and rotation amount of the Y motor are calculated and output to the drive unit 17b via the connection line 24.

The driving unit 17b of the XY robot 17 is connected to the CCD camera supporting unit 1 by the connecting unit 17d as described above.
7c mechanically coupled to the CCD camera 15
Are driven in the X and Y directions.

Due to the connection relationship between the sequencer 19 and the XY robot 17 as described above, each time the positioning signal output from the sequencer 19 is input to the controller 17a of the XY robot 17, the rotation direction of each motor is changed. Is converted into an X signal and a Y signal indicating the rotation amount and sent to the driving unit 17b.

Each time the drive unit 17b inputs a new X signal or Y signal, the drive unit 17b starts each motor to move the CCD camera 15 to a new photographing position. That is, CC
The D camera 15 positions the plurality of imaging regions in the order instructed by the sequencer 19.

The output of the CCD camera 15 is connected to the input of the image processing device 18 by a connection line 25. A digital image signal obtained by scanning each CCD element of the CCD camera 15 through the connection line 25 is an image processing device 1.
8 is supplied.

The image processing device 18 and the sequencer 19 are connected by connecting lines 26 and 27. When the sequencer 19 is informed by the status signal from the control unit 17a of the XY robot 17 that the positioning of the CCD camera 15 is completed, the sequencer 19 issues an image processing start command to the image processing device 18 through the connection line 26. send.

The image processing device 18 performs the following image processing. When inputting a program, window data representing a window size W, which is a criterion for determining the size of a shadow of a lead wire of a component, is input to the sequencer 19. The image processing device 18 is supplied with this window data from the sequencer 19 and stores it in the memory.

The image processing device 18 compares the size of the shadow of each lead wire of the component with the window data, and when the shadow is larger than the window, determines that the lead wire is completely inserted into the through hole. An OK signal is output to the sequencer 19 as a pass, and when the shadow is smaller than the window, it is determined that the lead wire is not inserted into the through hole, and a failure is output to the sequencer 19. Incidentally, this window can be appropriately adjusted by software.

The image processing device 18 also causes the monitor 20 to display a normal image or a binarized image. Which image is to be displayed is instructed to the image processing device 18 from the sequencer 19 based on the selection by the user.

Hereinafter, the overall operation of the odd-shaped component inspection machine which embodies the component mounting state inspection method according to the present invention will be described.
This will be described with reference to the flowchart shown in FIG.

(1) First, when the automatic operation of the odd-shaped component inspection machine is started, the printed circuit board conveying device starts to operate, the loader rail 13 moves, and the printed circuit board on which the parts are attached from the automatic lead wire insertion machine is completed. 1 is placed on the loader rail 13 and carried in. The monitor camera 14 sends a detection signal to the sequencer 19 when the printed circuit board 1 mounted on the loader rail 13 reaches a predetermined position. As a result, the sequencer 19 controls the printed circuit board transfer device to stop the loader rail 13, and as a result, the printed circuit board 1 stops at a predetermined position (step ST1,
ST2).

(2) Next, the insertion state of the lead wire of the component of the printed board 1 is inspected by the shadow of the lead wire (step ST3). In this inspection, the CCD camera 15 is positioned directly below the inspection region, the inspection region is photographed by the CCD camera 15, the photographed image is binarized, and the binarized image data is compared with the window. It is automatically performed by a series of operations. When there are a plurality of inspection parts, the inspection is repeated for each inspection part in the order designated by the sequencer 19.

(3) If the size of the shadow of the lead wire in the inspection region is larger than the window, it is set to OK, and if it is small, it is set to NG (step ST4).

(4) When all the inspection parts are OK, the sequencer 19 controls the printed circuit board transfer device to move the loader rail 13, and as a result, the printed circuit board which has passed the inspection is deformed by the loader rail 13. It is carried out (step ST5).

At the same time, a new printed circuit board is carried in. Steps ST1 to ST5 are repeated while there is no rejected printed circuit board.

(5) When the printed circuit board fails in step ST4, "NG" is displayed on the screen of the multi-display 21 and a warning is given by a buzzer or the like (step ST6).

(6) With respect to the printed circuit board 1 which has become NG, the inspector confirms the insertion state of the lead wire of the component (step ST7), and the required treatment, for example, the lead wire in the automatic insertion machine is performed. After being reinserted, etc., it is remounted on the loader rail 13 and the procedure from step ST1 is repeated.

In the above-mentioned embodiment, the structure is such that the components mounted on the printed circuit board are irradiated with light from an oblique direction. However, even if the components are irradiated with light from directly above. Good. In this case, the inspection method may be based on the assumption that there is no shadow of the light applied to the component.

For example, light is radiated vertically to the components and wirings mounted on the printed circuit board in advance, and the shadow state is patterned (window). Since the patterned data illuminates the component in the vertical direction, it becomes a very simple shadow pattern.

Then, the shaded state is collected in the light radiated from the vertical direction at the predetermined position where the printed circuit board is conveyed, and the shaded state is compared with the patterned data. This comparison is based on a small amount of data, and it becomes possible to speed up the determination of suitability for component mounting.

[0070]

The component mounting state inspection method according to the present invention having the above-described structure has the following effects.

(1) The printed board on which the component is mounted is irradiated with light, and the mounted state of the component is inspected by the shade of light, so that the mounted state can be visually inspected without directly touching the printed board. Even if it is not necessary, there is an extremely excellent effect that the mounting state of components can be inspected accurately and quickly.

(2) By irradiating light obliquely, appropriate light corresponding to the mounting state of the component can be applied to accurately extract the mounting state of the component due to shading. It has an extremely excellent effect that the wearing state can be inspected accurately and quickly.

(3) Since the light is directed to the lead wires of the component, the mounting state of the component can be inspected by a simple shaded pattern, for example, the lead wire of the electronic component mounted on the printed circuit board can be printed. Since it is possible to automatically determine whether or not it has been completely inserted into the through hole of the board, there is no need to perform a visual component lead inspection as in the conventional case, and the inspection time is shortened and the inspection efficiency is improved. It has an extremely excellent effect.

Further, since the quality of the lead wire is judged automatically by comparing the size of the shadow of the lead wire with a predetermined window, there is no artificial drop in the inspection, and the skilled inspection is possible. It also has an extremely excellent effect that the need for personnel is eliminated and the quality of the printed circuit board is improved.

(4) Since the shadows of the parts are photographed by the CCD camera to be binarized data, the shadow information of the parts can be easily digitalized and the pattern can be easily identified. It has an excellent effect.

(5) By comparing the shadow of the component with a predetermined pattern to inspect the mounting state of the component, even if the component mounted on the printed circuit board is changed, it can be easily changed. It becomes easy to create a pattern corresponding to the mounted state of the parts, and it is possible to easily inspect many kinds of printed circuit boards with a small amount, which is an extremely excellent effect.

(6) By comparing the shadow of the part with binarized data and comparing it with a predetermined pattern,
This has an extremely excellent effect that the identification based on the pattern can be performed accurately and quickly.

(7) Binarized data of the shadows of the parts photographed by the CCD camera and a predetermined pattern can be displayed at the same time, so that the inspection can be performed automatically and the shadows can be visually compared with each other. It is possible to perform the above, and there is an extremely excellent effect that the inspection accuracy can be improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing the principle of a component mounting state inspection method according to the present invention.

FIG. 2 is a schematic explanatory view showing an internal front surface of the embodiment of the inspection system for the component mounting state.

FIG. 3 is a schematic explanatory view showing an inner side surface of the embodiment.

FIG. 4 is an explanatory diagram showing a normal image displayed on a monitor on the back surface of a printed circuit board taken by a CCD camera in the embodiment.

FIG. 5 is an explanatory diagram showing a binarized image displayed on a monitor as an image binarized by the image processing apparatus in the embodiment.

FIG. 6 is a block diagram showing an electrical configuration of the embodiment.

FIG. 7 is a flowchart showing the overall operation of the embodiment.

[Explanation of symbols]

 1 Printed Circuit Board 2 Parts 3, 4 Lead Wires 5, 6 Through Hole 7 Light Source 8, 9 Lead Shadow 10 CCD Camera 11 Image Processing Device 12 Boxes 12a, 12b Partition Plate 13 Loader Rail 14 Monitor Camera 15 CCD Camera 16 Light Source 17 XY robot 17a XY robot 17 control unit 17b Same drive unit 17c Same CCD camera support unit 17d Same connection unit 18 Image processing device 19 Sequencer 20 Monitor 21 Multi-display and input / output device 22-27 Connection line

Claims (7)

[Claims] 1. A component mounted on a printed circuit board, which is irradiated with light from a predetermined direction, and a mounting state of the component is inspected from a shadow of the component generated by the light irradiated from the predetermined direction. How to check the wearing condition. 2. The method for inspecting a component mounting state according to claim 1, wherein the light from the predetermined direction is emitted from an oblique direction. 3. The method for inspecting a component mounting state according to claim 1, wherein the lead wire of the component projecting on the back surface of the printed circuit board is irradiated with light from the predetermined direction. . 4. The component mounting state inspection according to claim 1, 2 or 3, wherein the shadow generated from the printed circuit board mounted on the component is imaged by a CCD camera and is binarized. Method. 5. The method for inspecting a component mounting state according to claim 4, wherein the binarized data is compared with a predetermined pattern to inspect a component mounting state. 6. The method for inspecting a component mounting state according to claim 4, wherein the shadow of the component photographed by the CCD camera and the predetermined pattern can be displayed at the same time. 7. The method for inspecting a component mounting state according to claim 5, wherein the predetermined pattern is appropriately adjustable.