JPH0486548A - Packaged substrate appearance inspection device - Google Patents

Abstract

PURPOSE:To enable packaging state to be judged accurately by obtaining height data corresponding to traveling position of each traveling scanning region based on scattered light which is obtained due to reflection from a packaging surface of a printed-circuit board by scanning of laser beam. CONSTITUTION:A laser beam 16 from a laser light source 15 is emitted onto a printed-circuit board 11, the packaging surface is entirely scanned, and the reflected scattered light is subjected to position detection 22 and a position signal 23 is fed to an image operation processing means 30. Then, the means 30 converts a signal 23 into height data of parts 12 which are packaged onto the printed-circuit board 11 and then outputs it to a judgment processing means 40. Then, the means 40 shifts a traveling scanning region which is stored 60 to a specified position, takes out height distribution data at a position corresponding to the position, obtains sum of height distribution data at each position, and a maximum position detection circuit detects a position with the maximum data sum and then outputs it to the judgment circuit, thus enabling the judgment circuit to compare the position information with a threshold value and accurately judges the packaging state of the parts 12 for the printed-circuit board 11.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a mounted board appearance inspection apparatus () for inspecting mounting defects by detecting the shape, mounting position, etc. of components mounted on a printed board.

2. Description of the Related Art Conventionally, devices for inspecting components mounted on printed circuit boards for defective mounting have been widely used as suitable means for detecting defective boards on a production line.

FIG. 6 is an explanatory diagram showing the configuration of a conventional mounted board appearance inspection apparatus, and FIG. 7 is an explanatory diagram showing the positional relationship between the scanning area and the printed circuit board in the conventional mounted 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 measurement unit that measures the height distribution of the mounting surface of the printed circuit board 11 with the component 12 mounted thereon. It is.

This three-dimensional coordinate measurement unit 703 includes a distance sensor 704 that measures distance using the principle of triangulation using a laser and a light receiving element, and a component 12 that is mounted based on the distance data obtained by this distance sensor 704. The height distribution calculation circuit 705 calculates the height distribution of the mounted surface of the printed circuit board 11.

706 shows the state in which the component 12 is accurately mounted.
Reference height distribution data storage memory 707 storing height distribution data regarding the mounting surface of the printed circuit board 11
is a square error for calculating the square error between the height distribution data of the mounting surface of the printed circuit board 11 detected by the three-dimensional coordinate measuring unit 703 and the reference height distribution data stored in the reference height data storage memory 706. This is an error calculation circuit, and is roughly composed of a subtraction circuit 708 and a square calculation circuit 709.

710 indicates a plurality of scanning areas 715, 716, and 717 at positions corresponding to each component 12 mounted on the printed circuit board 11 within a mask area of the same size as the printed circuit board 11.
．． 718 is a mask data storage memory storing set mask data.

These scanning areas 715, 716, 717, and 718 are set so that their outer edges are shifted inward from the outer frame of the standard mounting position of each component 12 by the positional deviation tolerance range dimension. This is for detecting a positional shift of the component 12 exceeding .

711 multiplies the square error calculated by the square error calculation circuit 707 with a mask using the mask data stored in the mask data storage memory 710 to calculate each scanning area 715.
．． 716.717.718, and the extracted squared errors are applied to each scanning area 715.716.716.
This is a cumulative addition circuit that performs cumulative addition every 717.718.

712, each scanning area 715 is
．． The cumulative addition value accumulated for every 716.717.718 is divided by the cumulative addition number, and each scanning area 715.716
．． This is a mean square error calculation circuit that calculates the mean square error for every 717.718.

713 is each scanning area 715.716.717.718
A reference threshold storage memory 714 stores a reference threshold value for each mean square error, and compares the mean square error with the reference threshold value to determine whether the mounting state of the component 12 on the printed circuit board 11 is good or not. This is a comparison/judgment circuit that determines.

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

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

To specifically explain the measurement by the three-dimensional coordinate measuring unit 703, 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 from the distance sensor 704 to the component 12 The distance to the mounting surface of the printed circuit board 11 is measured by a laser emitted from the distance sensor 704, and the height calculation circuit 7O5 calculates height distribution data regarding the mounting surface of the printed circuit board 11 based on the second measurement data.

Printed circuit board 1 calculated by three-dimensional coordinate measurement unit 703
The height distribution data regarding the mounting surface of No. 1 is sent to the square error calculation circuit 707, where the square error with respect to the reference height distribution data stored in the reference height data storage memory 706 is calculated.

To specifically explain the calculation of the square error by the square error calculation circuit 707, the height distribution data regarding the mounting surface of the printed circuit board 11 calculated by the three-dimensional coordinate measurement 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 a subtraction circuit 708, and the value calculated by this subtraction circuit 708 is squared by a square calculation circuit 709 to calculate a squared error.

The square error calculated by the square error calculation circuit 707 includes:
The scanning area 7 is masked by mask data stored in the mask data storage memory 710.
Only the squared error at 15.716.717.718 is extracted.

The extracted squared error is calculated for each scanning area 715.716.7
The cumulative addition circuit 711 performs cumulative addition for each scan area of 17.718, and the cumulative addition value is further divided by the cumulative addition number by the mean square error calculation circuit 712 to obtain each scanning area 715.716.717.718. The mean squared error for each time is calculated.

Further, the mean square error for each scanning area 715, 716, 717, 718 is compared with the threshold value stored in the standard threshold storage memory 713 in the comparison/judgment circuit 714. Part 1
The quality of the mounting state of No. 2 is determined.

Problems to be Solved by the Invention However, in the above-mentioned conventional mounted board exterior inspection apparatus,
When comparing the reference height data stored in the reference height distribution data storage memory 706 and the height distribution data obtained by the three-dimensional coordinate measurement unit 703, for example, the printed circuit board 1
1 is warped, there is a problem in that variations in height distribution data due to the warp cannot be corrected and inspection accuracy cannot be improved.

In addition, in the above-mentioned conventional mounted board exterior inspection device, the component 12
scan area 715.716.717.718 only on the plane of
As shown in FIG. 7, the component 12 that should originally be mounted on the standard mounting position 719 of the printed circuit board 11, indicated by the broken line in the figure, causes rotational deviation as indicated by the solid line in the figure. The position? 20, each scanning area 715, 716, 717, 718 are all the mounting positions of the component 12? 20, there was a problem in that mounting defects could not be detected.

Furthermore, if the height distribution data obtained by the three-dimensional coordinate measurement unit 703 contains noise, the height distribution data of the component 12 and the printed circuit board 11 in the mounted state as shown in FIG. As shown in Figure (b), the mean square error calculated by the mean square error calculation circuit 712 becomes large, and the problem is that an item whose mounting condition should originally be determined to be good may be determined to be defective. There was a point.

The present invention solves the above-mentioned problems, and accurately determines the quality of the mounting state of components on a printed circuit board without degrading inspection accuracy due to noise in height distribution data and without errors in determining pass/fail due to warpage of the printed circuit board. It is an object of the present invention to provide a mounted board appearance inspection device that can make judgments.

Means for Solving the Problems In order to achieve the above object, the present invention provides a moving means for moving a printed circuit board on which components are mounted, a laser light source,
A laser beam scanning means that scans the laser beam from this laser light source onto the mounting surface of the printed circuit board, and a scattered light reflection that changes the optical axis of the scattered light obtained by being reflected from the mounting surface of the printed circuit board by scanning the laser beam. a 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 an image calculation means for calculating height distribution data regarding the mounting surface of the printed circuit board based on the position signal. a processing means, a scanning range position data storage means for storing positional data of a plurality of scanning ranges set corresponding to the component mounting position on the printed circuit board, and a scanning range position data storage means for storing data of a moving scanning region that moves within each scanning range. and a determination processing means for determining whether the mounting state of the component on the mounting surface of the printed circuit board is good or bad based on the height distribution data corresponding to the moving position of each moving scanning region. .

Effect of the Invention With the above-described configuration, the present invention is capable of accurately determining the quality of the mounting state of components on the printed circuit board without degrading the inspection accuracy due to noise in the height distribution data, without making mistakes in determining pass/fail due to warping of the printed circuit board. can.

Embodiments Hereinafter, embodiments of the present invention will be described based on the drawings. 1st
FIG. 1 is a schematic perspective view of a mounted board appearance inspection apparatus according to an embodiment of the present invention.

In FIG. 1, 11 is a printed circuit board, 12 is a component mounted on the printed circuit board 11, and 13 is a printed circuit board 11.
15 is a laser light source, and 16 is a laser beam from the laser light source 15.

17 is a polygon mirror; 18 is a reflecting mirror for guiding the laser beam 16 to the polygon mirror 17; 19 is a mechanical θ lens;
Reference numeral 0 designates a reflecting mirror, and laser beam scanning means P uses the polygon mirror 17, the reflecting mirror 18, and the fθ lens 19 to irradiate a laser beam 16 from a laser light source 15 onto the printed circuit board 11 to scan the mounting surface thereof. It consists of

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

21 is a condenser lens that condenses the scattered light whose optical axis direction has been changed by the scattered light reflection means R; 22 is a condenser lens 21
It is a position detection element that receives scattered light focused by the T and outputs a position signal 23 based on the incident light.
It consists of

30 is an image calculation processing means for calculating height distribution data of the component 12 from the position signal 23, and 4° is a determination processing means for determining whether the mounting state of the component 12 on the printed circuit board 11 is good or bad.

Further, as shown in FIGS. 3(a) and 3(b), 5o is a scanning range position in which position data of scanning ranges 301, 302, and 303 set in advance at the mounting position of the component 12 on the printed circuit board 11 is stored. The data storage means 60 is a moving scanning area data storing means for storing data regarding the sizes of the moving scanning areas 307, 308, and 309 that are each movably set within the scanning ranges 301, 302, and 303. .

As shown in FIG. 2, the image calculation processing means 30 is an analog converter that performs analog/digital conversion of the position signal 23 outputted from the position detecting element 22 at the timing of the synchronization signal.
/' A digital converter 31 (hereinafter referred to as A/D converter), a position calculation circuit 32 that calculates height distribution data regarding the mounting surface of the printed circuit board 11 based on the position signal 23 converted to a digital signal, and The height distribution data storage memory 33 stores height distribution data and outputs it to the determination processing means 40.

Further, as shown in FIG. 2, the determination processing means 40 converts the moving scanning area 307, 308, 309 into the scanning range 301.
302, 303, and 307, 308, 3.
The adding circuit 42 extracts the height distribution data in the movement range of 09 from among the manually inputted data from the height distribution data storage memory 33 and adds the data.

Further, the determination processing means 40 includes a maximum position detection circuit 43 that detects the position where the height distribution data is maximum in the movement range of the movement scanning area 307, 308, 309 based on the addition result of the addition circuit 42; Position detection circuit 43
It has a determination circuit 44 that determines whether the mounting state is good or bad based on the detection result of , and threshold storage means 45 that stores a threshold value that is a reference for determination by this determination circuit 44 .

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

The printed circuit board ll is scanned in the vertical direction by the laser beam 16.
The scattered light reflected from above is transferred to the printed circuit board 11 and f.
The light is reflected by a reflection mirror 20 provided between the θ lens 19 and is focused on the position detection element 22 via the fθ lens 19 and the polygon mirror 17, and then through the condenser lens 21. Position signal 2 output from position detection element 22
3 is manually input to the image calculation processing means 30.

The image calculation processing means 30 performs calculations to convert the position signal 23 input at the timing of the synchronization signal into height distribution data of the printed circuit board 11 and the components 12 mounted on the printed circuit board 11, and converts the measured height distribution data into actual height distribution data. is output to the determination processing means 40, and such an operation is performed on the entire surface of the printed circuit board 11.

Next, the operations of the image calculation processing means 30 and the determination processing means 40 will be explained in detail using FIG. 2.

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

In this embodiment, the position detection element 22 is a PSD (Po5
ition-8ensitive Detectors
; semiconductor device detection element), 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 each electrode.

In the position calculation circuit 32, the PS converted into a digital signal is
Currents I] and I2 from the picture electrode of D are calculated using the following equation ('I) to obtain height data.

Height data = K・(II-12)/(11+12) (where K is a coefficient for normalization)... (I) The height distribution data obtained in this way is The data is stored in the data storage memory 33 and output to the determination processing means 40.

In the determination processing means 40, the scanning range position data storage means 5
Within the scanning ranges 301, 302, and 303 stored in 0, the moving scanning areas 307, 308, and 309 stored in the moving scanning area data storage means 60 are moved to the position determined by the moving scanning area position determining means 41. let

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

Along with this, in the maximum position detection circuit 43, the addition circuit 4
Based on the height distribution information signal from 2, the position where the sum of the height distribution data is maximum is detected and the position information signal is output to the determination circuit 44.
Compare the position information signal from 3 with a threshold value stored in the threshold storage means 45 to determine whether the input position information signal is within the range of the threshold value, The mounting state of the component 12 on the printed circuit board 11 is determined.

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

In FIGS. 3(a) and 3(a), 304 indicates the normal mounting position of the component 12 when the printed circuit board 11 is viewed in plan, and the vertical direction in the figure is 304 with respect to the printed circuit board 11. One scanning range 301 in the horizontal direction in the figure, and two scanning ranges 302 and 303 in the horizontal direction in the figure, taking into account the mounting position deviation of the component 12, respectively, the normal mounting position 304 of the component 12.
The height and width are set to be longer than the width.

Furthermore, 305.306 in Figure 3 (]) and (b)
indicate the position of the component 12 actually mounted on the printed circuit board 11, and the mounting position 305 indicates the state where the mounting position is shifted to the upper left in the figure, and the mounting position 306 indicates the state where the rotational shift has occurred. It shows.

In the scanning range position data storage means 50 in this embodiment, the unique value of each scanning range 301, 302, 303 is A 1
, A 2, A3, and each eigenvalue A1, A2, A 3
Fig. 3 (
a), (b) Stores scanning range position data in which the XY coordinates of the upper and lower right corners of the medium pressure correspond to each other.

On the other hand, the moving scanning area data storage means 6 in this embodiment
0, the size of the moving scanning area 307, 308, 309, that is, the length of the moving scanning area 307 in the Y direction in the figure, and the length of the moving scanning area 308, 309 in the X direction in the figure are stored, respectively. has been done.

When the moving scanning area 307.308.309 according to the above settings is moved within the scanning range 301.302.303, the adding circuit 42 uses the height distribution data input from the measured height distribution data storage memory 33. The height distribution data of the corresponding position is extracted from among and added.

For example, if the moving scanning area 308 is moved to the left from the inner cloth in FIGS. 3(a) and 3(b) within the scanning range 302, and the values calculated by the adding circuit 42 are shown in a graph. , as shown in Figure 4.

That is, when the movable scanning area 308 is located away from the component 12, the sum of the data added by the adding circuit 42 becomes the sum of the heights of the printed circuit board 11, and the movable scanning area 308 moves to face the component 12. The sum of the data added by the adder circuit 42 increases.

For example, if the size of the moving scanning area 308 is the same as the width of the component 12 in FIG. 3(a), then the moving scanning area 308
When the position is directly above the component 12, the sum of the data added by the adding circuit 42 becomes maximum, and the maximum position detection circuit 43 detects this position.

Therefore, as shown in FIG. 4, when the component 12 is mounted at the regular mounting position 304, the position where the sum of the data added by the adding circuit 42 is maximum is B1, as shown in FIG.
) if the component 12 is mounted at the actual mounting position 305, B2, and the actual mounting position 3 shown in FIG. 3(b).
If component 12 is mounted on 06, it is detected as B3. In the threshold value storage means 45, 1 in FIG.
A threshold value indicating the permissible range of mounting position deviation of the component 12 indicated by K2 is stored, and based on this, the determining means 44 determines whether the positions B1, B2, and B3 detected as described above are 1 or 1. It is determined whether the value is within the range of 2 and .

By performing the same operation for the scanning ranges 301 and 303, positional deviation and rotational deviation of the component 12 can be detected. In this case, even if the position signal 23 contains noise or the printed circuit board 11 is warped, the position where the sum of data added by the adding circuit 42 is maximum will not be affected. Therefore, part 1
2, the mounting position and the quality of the mounting state can be accurately detected.

In addition, in the above embodiment, the individual scanning ranges 301.30
The quality of the mounting state of the component 12 was determined every 2.303 seconds. For example, as shown in FIG.
If 02.303 is grouped, the regular mounting position 30
The rotation angle θ] of the actual mounting position with respect to 4 can be determined.

In this case, the X coordinate values X],
03 can be determined from the distance y from the following formula, tan θ1 = (xl - xl ly) The mounted component 1
2, and based on this, it is possible to determine whether the mounting state of the component 12 is good or bad.

In addition, in the above embodiment, the scanning range 301.302.303
Moving scanning area 30 within the range of ? , 308, 309 are moved and the position where the sum of the height distribution data at the moving position is maximum is compared with the threshold value to make the determination.As shown in FIG. 4, each scanning range 301. Maximum value S1 and minimum value S2 regarding the sum of height distribution data in 302.303
It is also possible to determine the difference between the parts 12 and the parts 12, and thereby detect double stacking of parts 12 or missing parts.

In this case, when two parts 12 are stacked, the difference between the maximum value S] and the minimum value S2 becomes large, and when the part 12 is out of stock, the difference between the maximum value S1 and the minimum value S2 becomes large. becomes smaller.

Effects of the Invention As described above, according to the present invention, there is provided a moving means for moving a printed circuit board on which components are mounted, a laser light source, and a laser beam scanning system 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 the scattered light obtained by being reflected from the mounting surface of the printed circuit board by scanning a laser beam, and a scattering 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 by scanning the laser beam; a position detecting means for outputting a position signal regarding the printed circuit board, an image calculation 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 position of the printed circuit board. scanning range position data storage means for storing positional data of the range; moving scanning area data storage means for storing data of moving scanning areas that move within each scanning range; and a 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 density distribution data.

Therefore, there is no deterioration in inspection accuracy due to noise in the height distribution data, there is no error in quality determination due to warping of the printed circuit board, and it is possible to accurately determine the quality of the mounting state of components on the printed circuit board.

[Brief explanation of the drawing]

1 is a schematic perspective view of a mounted board appearance inspection apparatus according to an embodiment of the present invention, FIG. 2 is a detailed block diagram of the main parts of FIG. 1, and FIGS. 3(a) and 3(b) are FIG. 1 is an explanatory diagram showing the relationship between the scanning range and the component mounting position in the mounted board appearance inspection apparatus; FIG. 4 is an explanatory diagram showing the change in the sum of height distribution data when the movable scanning area is moved; FIG. 5 is an explanatory diagram illustrating a positional deviation detection operation in another embodiment of the present invention, FIG. 6 is a schematic perspective view of a conventional mounted board appearance inspection apparatus, and FIG. 7 is a mounting board shown in FIG. 6. FIG. 8(a) is an explanatory diagram showing the relationship between the mask area, the scanning area, and the component mounting position in the board appearance inspection apparatus, and FIG. 8(b) is an explanatory diagram showing the mounting state of components mounted on the printed circuit board. is shown in Figure 8 (
Obtained by scanning the mounting surface of the printed circuit board shown in a),
FIG. 2 is an explanatory diagram showing height distribution data including noise. DESCRIPTION OF SYMBOLS 11... Printed circuit board, 12... Parts, 13... Transport means, 15... Laser light source, 16... Laser light,
23... Position signal, 30... Image calculation processing means, 4
0... Determination processing means, 50... Scanning range position data storage means, 60... Moving scanning area data storage means, 3
゜1.302.303...Scanning range, 307.3゜8
．． 309...Moving scanning area, P/laser beam scanning means,
R: Scattered light reflecting means, T: Position detecting means. 1 Prut Water Board - 1000 Lights 1 Thousand 1 Means Scattered Light Reflective Means Name of Attorney Patent Attorney Shige Awano Takaha 1 Figure Figure Figure Submask J Shi Eve! Fig. Fig. Fig. Fig. θ3 Three-return nine-point measuring section

Claims (1)

[Claims] A moving means for moving a printed circuit board on which components are mounted, a laser light source, a laser beam scanning means for scanning a mounting surface of the printed circuit board with laser light from the laser light source, and mounting of the printed circuit board by scanning the laser light. a scattered light reflecting means for changing the optical axis of the scattered light obtained by reflection from the surface; a 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; Image calculation processing means that calculates height distribution data on the mounting surface of the printed circuit board based on position signals, and scanning range position data storage that stores position data of a plurality of scanning ranges set corresponding to component mounting positions on the printed circuit board. a moving scanning area data storage means for storing data of a moving scanning area that moves within each scanning range; A mounted board appearance inspection device comprising a determination processing means for determining whether the mounting state of components is good or bad.