JPH0765967B2 - Mounted board visual inspection device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting board appearance inspection device that detects a mounting defect by detecting the shape, mounting position, etc. of a component mounted on a printed board.

2. Description of the Related Art Conventionally, a device for inspecting a mounting failure of a component mounted on a printed circuit board has been widely used as a suitable detection means for a mounting failure board on a line.

FIG. 6 is an explanatory view showing the configuration of a conventional mounting board appearance inspection apparatus, and FIG. 7 is an explanatory view showing the positional relationship between a scanning area and a printed board in the conventional mounting board appearance inspection apparatus. In the figure, 11 is a printed circuit board, 12 is a component mounted on the printed circuit board 11, and 703 is a three-dimensional coordinate measuring unit that measures the height distribution of the mounting surface of the printed circuit board 11 with the component 12 mounted thereon. Is.

The three-dimensional coordinate measuring unit 703 mounts the component 12 on the basis of a distance sensor 704 that measures a distance according to the principle of triangulation using a laser and a light receiving element, and the distance data obtained by the distance sensor 704. And a height distribution calculation circuit 705 for calculating the height distribution of the mounting surface of the printed circuit board 11 thus formed.

Reference numeral 706 denotes a reference height distribution data storage memory in which data of height distribution regarding the mounting surface of the printed circuit board 11 in a state where the component 12 is accurately mounted is stored, and 707 is detected by the three-dimensional coordinate measuring unit 703. The height distribution data of the mounted surface of the printed circuit board 11 and the reference height data storage memory 70
A square error calculation circuit that calculates a squared error from the reference height distribution data stored in 6, and is roughly configured by a subtraction circuit 708 and a square calculation circuit 709.

710 is mask data in which a plurality of scanning areas 715, 716, 717, 718 are set at positions corresponding to respective components 12 mounted on the printed board 11 in a mask area having the same size as the printed board 11. Is a mask data storage memory that stores

The scanning areas 715, 716, 717, and 718 have the outer edges of the respective parts.
It is set so as to be displaced inward from the outer frame of the standard mounting position of 12 by the displacement allowable range dimension, and is for detecting the displacement of the component 12 exceeding the allowable dimension.

711, the squared error calculated by the squared error calculation circuit 707 is masked by the mask data stored in the mask data storage memory 710, and each scanning area 715, 716, 71
This is a cumulative addition circuit that extracts a squared error for each 7 and 718 and cumulatively adds the extracted squared error for each of the scanning regions 715, 716, 717, and 718.

712 is a cumulative addition circuit 711 for each scanning area 715, 716, 71
This is a mean square error calculation circuit that calculates the mean square error for each scanning area 715, 716, 717, 718 by dividing the cumulative addition value cumulatively added for each 7, 718 by the number of clear additions.

Reference numeral 713 is a reference threshold value storage memory that stores reference threshold values for the mean square error for each scanning area 715, 716, 717, 718, and 714 is a comparison between the mean square error and the reference threshold value. A comparison / determination circuit that determines the quality of the mounting state of the component 12 on the printed circuit board 11.

Next, the operation of the above conventional example will be described.

First, the three-dimensional coordinate measuring unit 703 measures the height distribution of the mounting surface of the printed circuit board 11 on which the component 12 is mounted.

The measurement by the three-dimensional coordinate measuring unit 703 will be specifically described. The distance from the distance sensor 704 to the mounting surface of the printed circuit board 11, that is, the distance from the distance sensor 704 to the printed circuit board 11, or the distance sensor 704 to the component 12. The distance to is measured by the laser emitted from the distance sensor 704,
Based on this measurement data, the height calculation circuit 705 calculates height distribution data regarding the mounting surface of the printed board 11.

The height distribution data regarding the mounting surface of the printed circuit board 11 calculated by the three-dimensional coordinate measuring unit 703 is a square error calculation circuit.
It is sent to 707, and the squared error with the reference height distribution data stored in the reference height data storage memory 706 is calculated here.

The calculation of the squared error by the squared error calculation circuit 707 will be specifically described. The height distribution data regarding the mounting surface of the printed circuit board 11 calculated by the three-dimensional coordinate measuring unit 703 and the reference height data storage memory 706 are stored. A numerical difference from the stored reference height distribution data is calculated by the subtraction circuit 708, and the square calculation circuit 709 squares the value calculated by the subtraction circuit 708 to calculate a squared error.

The squared error calculated by the squared error calculation circuit 707 is masked by the mask data stored in the mask data storage memory 710, whereby the scanning areas 715, 7
Only the squared error at 16,717,718 is extracted.

The extracted squared error is in each scanning area 715, 716, 717, 718.
Each of them is cumulatively added by the cumulative addition circuit 711, and the cumulative addition value is further added to the mean square error calculation circuit 71.
Divided by the cumulative addition number by 2 to obtain each scan area 715, 71
The mean square error for every 6, 717, 718 is calculated.

Further, the mean square error for each of the scanning areas 715, 716, 717, 718 is compared with the threshold value stored in the standard threshold value storage memory 713 in the comparison and determination circuit 714, whereby the printed circuit board 11 is processed. The quality of the mounting state of the component 12 is determined.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the conventional mounting board exterior inspection device,
When comparing the reference height data stored in the reference height distribution data storage memory 706 with the height distribution data obtained by the three-dimensional coordinate measuring unit 703, for example, if the printed circuit board 11 is warped, this warpage There is a problem in that it is not possible to correct the variation of the height distribution data due to, and it is not possible to improve the inspection accuracy.

Further, in the conventional mounting board exterior inspection apparatus described above, since the scanning areas 715, 716, 717, 718 are set only on the surface of the component 12, as shown in FIG. Parts to be mounted at the standard mounting position 719 indicated by
2 is the position where the rotation shift occurs as shown by the solid line in the figure 7
When mounted on 20, the scanning areas 715, 716, 717, 718 all face the mounting position 720 of the component 12, so that there is a problem that a mounting failure cannot be detected.

Furthermore, when the height distribution data obtained by the three-dimensional coordinate measuring unit 703 contains noise, the height distribution data of the mounted component 12 and the printed circuit board 11 as shown in FIG. As shown in FIG. 6B, the mean squared error calculated by the mean squared error calculation circuit 712 becomes large, and there may be cases where the originally mounted state should be determined to be good. There was a point.

The present invention is to solve the above problems, there is no deterioration in inspection accuracy due to noise in the height distribution data, there is no mistake in the quality judgment due to the warp of the printed circuit board, and the quality of the mounted state of the component on the printed circuit board can be accurately determined. An object of the present invention is to provide a mounted board appearance inspection device capable of making a determination.

Means for Solving the Problems In order to achieve the above object, the present invention has a moving means for moving a printed circuit board on which components are mounted, a laser light source,
Laser light scanning means for scanning the laser light from the laser light source onto the mounting surface of the printed circuit board, and scattered light reflection for changing the optical axis of the scattered light reflected from the mounting surface of the printed circuit board by scanning the laser light. Means, position detecting means for outputting a position signal regarding the mounting surface of the printed circuit board based on the scattered light from the scattered light reflecting means, and image calculation for calculating height distribution data regarding the mounting surface of the printed circuit board by the position signal. Processing means, scanning range position data storage means for storing position data of a plurality of scanning ranges set corresponding to component mounting positions on the printed circuit board, and data for a moving scanning area that moves within each scanning range. Moving scanning area data storage means and parts for the mounting surface of the printed circuit board based on the height distribution data corresponding to the moving position of each moving scanning area The quality of mounted state has a configuration and a determination processing section.

Effect With the above-described configuration, the present invention can accurately determine the quality of the mounting state of the component on the printed circuit board without the deterioration of the inspection accuracy due to the noise of the height distribution data and the error of the quality determination due to the warp of the printed circuit board. .

Embodiment An embodiment of the present invention will be described below with reference to the drawings. First
FIG. 1 is a schematic perspective view of a mounting board appearance inspection device according to an embodiment of the present invention.

In FIG. 1, 11 is a printed circuit board and 12 is a printed circuit board.
Reference numeral 13 is a component mounted on the substrate, 13 is a conveying means for moving the printed circuit board 11 in the direction of an arrow 14 in the figure, 15 is a laser light source, and 16 is a laser light from the laser light source 15.

17 is a polygon mirror, 18 is a laser beam 16 polygon mirror
A reflecting mirror for guiding to 17, a f.theta. Lens 19 and a reflecting mirror 20. The polygon mirror 17, the reflecting mirror 18, and f.theta.
The lens 19 constitutes laser light scanning means P for irradiating the laser light 16 from the laser light source 15 onto the printed board 11 to scan the mounting surface thereof.

Further, the polygon mirror 17, the fθ lens 19, and the reflection mirror 20 constitute a scattered light reflection means R for changing the optical axis of the scattered light of the laser light 16 which is irradiated and reflected on the mounting surface of the printed circuit board 11. There is.

Reference numeral 21 is a condenser lens for condensing the scattered light whose optical axis direction has been changed by the scattered light reflecting means R, and reference numeral 22 is the position where the scattered light condensed by the condenser lens 21 is incident.
These are the position detection elements that output 23, and these condenser lenses 21
And the position detecting element 22 constitute a position detecting means T.

Reference numeral 30 is an image calculation processing means for calculating the height distribution data of the component 12 from the position signal 23, and 40 is a determination processing means for determining the quality of the mounting state of the component 12 on the printed circuit board 11.

Further, as shown in FIGS. 3 (a) and 3 (b), reference numeral 50 denotes a scanning range position for storing position data of scanning ranges 301, 302, 303 preset at the mounting position of the component 12 on the printed circuit board 11. The data storage means 60 is the scanning range 301, 302,
Moving scan area 3 set to be movable within the range of 303
It is a moving scanning area data storage means for storing data regarding the sizes of 07, 308 and 309.

As shown in FIG. 2, the image calculation processing means 30 includes an analog / digital converter 31 (hereinafter, referred to as an A / D converter) for analog / digital converting the position signal 23 output from the position detection element 22 at the timing of the synchronization signal. The position calculation circuit 32 calculates the height distribution data regarding the mounting surface of the printed circuit board 11 based on the position signal 23 converted into a digital signal, and the height distribution data is stored in the determination processing means 40. It is composed of an output height distribution data storage memory 33.

As shown in FIG. 2, the determination processing means 40 includes moving scanning area position determining means 41 for moving the moving scanning areas 307, 308, 309 within the scanning ranges 301, 302, 303, and moving scanning. The height distribution data in the moving ranges of the areas 307, 308, and 309 are added from the data input from the height distribution data storage memory 33 and the addition circuit 42 is added.

Further, the determination processing means 40, the maximum position detection circuit 43 for detecting the position where the height distribution data is maximum in the movement range of the movement scanning regions 307, 308, 309 based on the addition result of the addition circuit 42, It has a judgment circuit 44 for judging the quality of the mounting state based on the detection result of the position detection circuit 43, and a threshold value storage means 45 for storing a threshold value as a reference for judgment by the judgment circuit 44. .

Next, the operation of the above embodiment will be described. The printed circuit board 11 on which the component 12 is mounted is fixed on the transfer means 13 and moved in the direction of arrow 14. Then, the laser light 16 from the laser light source 15 is guided to the rotating polygon mirror 17 via the three reflecting mirrors, and further the polygon mirror 17 and fθ are guided.
The printed circuit board 11 is illuminated by the lens 19. As a result, the printed circuit board 11 is two-dimensionally scanned in the vertical direction by the laser beam 16.

Scattered light reflected from the printed circuit board 11 by scanning the laser beam 16 in the vertical direction is reflected by the reflection mirror 20 provided between the printed circuit board 11 and the fθ lens 19, and fθ
The light is condensed on the position detection element 22 through the lens 19 and the polygon mirror 17 and further through the condenser lens 21. The position signal 23 output from the position detection element 22 is an image calculation processing means.
Entered in 30.

In the image calculation processing means 30, the position signal 23 input at the timing of the synchronizing signal is used for the printed circuit board 11 and the printed circuit board 11.
A calculation for converting the height distribution data of the component 12 mounted on the printed circuit board is performed, the measured height distribution data is output to the determination processing unit 40, and such an operation is performed on the entire surface of the printed board 11.

Next, the operations of the image calculation processing means 30 and the determination processing means 40 will be described in detail with reference to FIG.

The image calculation processing means 30 uses the position signal from the position detection element 22.
The A / D converter 31 converts 23 into a digital signal, and the digital signal is input to the position calculation circuit 32.

In this embodiment, a PSD (Position-Se
Semiconductor position detectors) are used, and the incident position of the reflected light incident on the PSD is such that the current flowing through the electrodes at both ends of the PSD is inversely proportional to the distance between the electrodes.

In the position calculation circuit 32, the currents I ₁ and I ₂ from both electrodes of the PSD, which are converted into digital signals, are calculated using the following formula (I) to obtain height data.

Height data = K · (I ₁ −I ₂ ) / (I ₁ + I ₂ ) (where K is a coefficient for normalization) (I) The height distribution data thus obtained is once It is stored in the measurement height data storage memory 33 and output to the determination processing means 40.

In the determination processing means 40, within the scanning ranges 301, 302, 303 stored in the scanning range position data storage means 50, the moving scanning area 30 stored in the moving scanning area data storing means 60
The 7, 308 and 309 are moved to the positions determined by the moving scanning area position determining means 41.

Then, the adder circuit 42 takes out the height distribution data of the position corresponding to the moving position from the data input from the measurement data storage memory 33, obtains the sum of the height distribution data for each position, and The result is output to the maximum position detection circuit 43 as a height distribution information signal.

Along with this, the maximum position detection circuit 43 detects the position where the sum of the height distribution data is maximum based on the height distribution information signal from the addition circuit 42 and outputs the position information signal to the determination circuit 44. In the determination circuit 44, the position information signal from the maximum position detection circuit 43 is compared with the threshold value stored in the threshold value storage means 45, and the input position information signal is within the threshold value range. It is determined whether or not there is, and the mounting state of the component 12 on the printed board 11 is determined.

Here, the relationship between the positions of the scanning ranges 301, 302, 303 and the component 12 is specifically shown in FIGS. 3 (a) and 3 (b). FIG. 3A shows a good mounting state, and FIG. 3B shows a defective mounting state.

In FIGS. 3A and 3A, 304 is the printed circuit board 11.
2 shows a regular mounting position of the component 12 when seen in a plan view. For this printed circuit board 11, one scanning range 301 in the vertical direction in the drawing and 2 in the horizontal direction in the drawing are shown. Book scanning range 3
02 and 303 are set to be longer than the vertical width and the horizontal width of the regular mounting position 304 of the component 12, respectively, in consideration of the mounting position deviation of the component 12.

Further, 305 and 306 in FIGS. 3A and 3B respectively indicate the positions of the components 12 actually mounted on the printed circuit board 11, and the mounting position 305 is displaced to the upper left in the drawing. And the mounting position 306 shows a state in which a rotation deviation occurs.

In the scanning range position data storage means 50 in this embodiment,
The eigenvalues of each scanning range 301, 302, 303 are A1, A2, A3,
Scanning range 301, 302, 303 for each eigenvalue A1, A2, A3
Of the upper left and lower right corners in FIGS. 3 (a) and 3 (b).
The scanning range position data corresponding to the XY coordinates is stored.

On the other hand, the moving scanning area data storage means 60 in this embodiment
Then, the sizes of the moving scanning regions 307, 308, 309, that is, the length in the Y direction in the drawing for the moving scanning region 307 and the length in the X direction for the moving scanning regions 308, 309 are stored. ing.

When the moving scanning areas 307, 308, 309 having the above settings are moved within the scanning ranges 301, 302, 303, the adding circuit 4
In 2, the height distribution data at the corresponding position is extracted from the height distribution data input from the measured height distribution data storage memory 33 and added.

For example, when the moving scanning region 308 is moved from the right to the left in FIGS. 3A and 3B within the scanning range 302, the values calculated by the adding circuit 42 are shown in the graph. , 4th
It becomes like the figure.

That is, when the moving scanning area 308 is located outside the component 12, the sum of the data added by the adding circuit 42 becomes the sum of the heights of the printed circuit boards 11, and the moving scanning area 308 moves to face the component 12. And the sum of the data added by the adder circuit 42 increases.

For example, assuming that the size of the moving scanning area 308 is the same as the width of the component 12 in FIG.
When the position immediately above 2 is reached, the sum of the data added by the adder circuit 42 becomes maximum, and the maximum position detection circuit 43 detects this position.

Therefore, as shown in FIG. 4, the component 12 is mounted at the proper mounting position.
When mounted on 304, the position where the sum of the data added by the adder circuit 42 is maximum is B1, and when the component 12 is mounted on the actual mounting position 305 shown in FIG. B
2. If the component 12 is mounted at the actual mounting position 306 shown in FIG. 3 (b), it is detected as B3. The threshold value storage means 45 stores a threshold value indicating an allowable range of the mounting position deviation of the component 12 shown by K1 and K2 in FIG. Position detected as
It is determined whether B1, B2 and B3 are within the range between K1 and K2.

By performing the same operation as above for the scanning ranges 301 and 303, it is possible to detect the positional deviation and the rotational deviation of the component 12. In this case, even if the position signal 23 contains noise or the printed circuit board 11 is warped,
There is no influence on the position where the sum of the data added by the adder circuit 42 is the maximum, and therefore, the mounting position of the component 12 and the quality of the mounting state can be accurately detected.

In the above embodiment, the individual scanning ranges 301, 302, 30
Whether the mounting state of the component 12 is good or bad is determined for every 3 units. For example, as shown in FIG. 5, the component 12 mounted with a rotation deviation is grouped by the horizontal scanning ranges 302 and 303 in the figure. If converted, the rotation angle θ ₁ of the actual mounting position with respect to the regular mounting position 304 can be obtained.

In this case, the X coordinate values X ₁ and x ₂ indicating the position of the component 12 in the lateral direction in the drawing within the respective scanning ranges 302 and 303, which are obtained by the operation shown in the above embodiment, and the scanning ranges 302 and 303 Distance y
Can be obtained by the following formulas _{and, tanθ 1 = (x 1 -x} 2) / y by the rotation angle theta ₁ of a magnitude determined, component 12 mounted
It is possible to determine the quality of the mounting state of the component 12 based on the degree of positional deviation of the component 12 obtained.

In the above embodiment, the moving scanning areas 307, 308, 309 are moved within the scanning ranges 301, 302, 303, and the position where the sum of the height distribution data at the moving position becomes maximum is compared with the threshold value. Although the judgment was made by using, as shown in FIG.
The difference between the maximum value S ₁ and the minimum value S ₂ related to the sum of the height distribution data in each scanning range 301, 302, 303 is calculated, and by doing so, it is possible to detect the double stacking of the component 12 and the missing component. Good.

In this case, the difference between the maximum values S ₁ and the minimum value S ₂ is increased when the 2-ply part 12 has occurred, the maximum values S ₁ and the minimum value S ₂ when the shortage of the component 12 occurs The difference between

EFFECTS OF THE INVENTION As described above, according to the present invention, moving means for moving a printed circuit board on which components are mounted, a laser light source, and laser light scanning for scanning the laser light from the laser light source on the mounting surface of the printed circuit board. Means, a scattered light reflecting means for changing the optical axis of scattered light obtained by reflecting from the mounting surface of the printed circuit board by scanning laser light, and a mounting surface of the printed circuit board based on the scattered light from this scattered light reflecting means. Position detecting means for outputting a position signal relating to the mounting surface of the printed circuit board, image processing means for calculating height distribution data regarding the mounting surface of the printed circuit board based on the position signal, and a plurality of scans set corresponding to the component mounting positions of the printed circuit board Scanning range position data storage means for storing the position data of the range, and moving scanning region data for storing the data of the moving scanning region that moves within each scanning range. The storage means and the determination processing means for determining the quality of the mounting state of the component on the mounting surface of the printed circuit board based on the height distribution data corresponding to the movement position of each movement scanning area are provided.

Therefore, it is possible to accurately determine the quality of the mounting state of the component on the printed circuit board without the deterioration of the inspection accuracy due to the noise of the height distribution data and the error of the quality determination caused by the warp of the printed circuit board.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a mounting board appearance inspection apparatus according to an embodiment of the present invention, FIG. 2 is a detailed block diagram of a main part of FIG. 1, and FIGS. 3 (a) and 3 (b) are 1 is an explanatory view showing a relationship between a scanning range and a component mounting position in the mounting board appearance inspection device of FIG. 1, and FIG. 4 is an explanatory view showing a change of a sum of height distribution data when a moving scanning region is moved, FIG. 5 is an explanatory view for explaining a positional deviation detecting operation in another embodiment of the present invention, FIG. 6 is a schematic perspective view of a conventional mounting board appearance inspection device, and FIG. 7 is a mounting of FIG. Explanatory drawing which shows the relationship between the mask area | region and scanning area | region in a board | substrate visual inspection apparatus, and component mounting position, FIG. 8 (a) is explanatory drawing which shows the mounting state of the component mounted on the printed circuit board, FIG. 8 (b). Is a high level including noise, which is obtained by scanning the mounting surface of the printed circuit board shown in FIG. Is an explanatory view showing the distribution data. 11 …… Printed circuit board, 12 …… Parts, 13 …… Transportation means, 15
...... Laser light source, 16 …… Laser light, 23 …… Position signal, 30
... image calculation processing means, 40 ... determination processing means, 50 ... scanning range position data storage means, 60 ... moving scanning area data storage means, 301, 302, 303 ... scanning range, 307, 308, 309
...... Movement scanning area, P ...... Laser light scanning means, R ...... scattered light reflecting means, T ...... position detecting means.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-2-10252 (JP, A) JP-A-2-114156 (JP, A) JP-A-49-83470 (JP, A) JP-A-3- 261850 (JP, A) JP-A-2-82367 (JP, A)

Claims (1)

[Claims] 1. A moving means for moving a printed circuit board on which components are mounted, a laser light source, a laser light scanning means for scanning a laser light from the laser light source on a mounting surface of the printed circuit board, and a laser light scanning. The scattered light reflecting means for changing the optical axis of the scattered light obtained by being reflected from the mounting surface of the printed circuit board, and the position for outputting the position signal related to the mounting surface of the printed circuit board based on the scattered light from the scattered light reflecting means. Detecting means, image calculation processing means for calculating height distribution data on the mounting surface of the printed circuit board based on this position signal, and position data of a plurality of scanning ranges set corresponding to component mounting positions of the printed circuit board are stored. Scanning range position data storage means, moving scanning area data storage means for storing data of a moving scanning area that moves within each scanning range, and each moving scanning area. Mounting board inspection system that includes a determination processing means the quality of mounting state of the component with respect to the mounting surface of the printed circuit board based on the height distribution data corresponding to the moving position of the.