JPH05332746A - Recognizing device of solder paste form - Google Patents

Abstract

PURPOSE:To precisely recognize the form of a solder paste by providing a means for color-photographing a base surface; a means for separating the image to each hue component; a digital converting means; a memory means; a specified image extracting means for extracting from the memory means; and image information showing the paste form. CONSTITUTION:The image on a printed board lighted by a light source is picked up by a color camera, and the color video signal is inputted to an image processing device 5. The input signal is separated into respective hue components of red, green and blue. Thereafter, the color video signal is converted into multi-value digital image information every picture element by A/D converters 12a, b, c, and then stored in the corresponding R-buffer memory 13a, G-buffer memory 13b, and B-buffer memory 13c, respectively. The image information of a specified value corresponding to the image of a solder paste 1 is extracted in picture element unit from the memories 13a, b, c by a specified image extracting part 14. This is stored in a memory 15 and displayed. Thus, the form of the solder paste can be precisely recognized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solder paste shape recognition device for recognizing the shape of a solder paste printed on a printed circuit board.

[0002]

2. Description of the Related Art Conventionally, inspection of a solder paste printed on a printed circuit board has been conducted by visual inspection. recent years,
Various inspection devices and solder paste shape recognition devices have been developed in order to eliminate such manual work. At present, as an inspection device, a device for performing a planar inspection by diffused light from a solder paste obtained by uniformly irradiating a printed circuit board surface with light from an oblique direction, or measuring an amount of solder by X-rays Devices are being developed.

However, in the case of the former inspection apparatus, since the diffusion surface other than the solder paste is extracted, the image becomes unclear throughout and it is difficult to obtain a stable inspection result. In addition, this inspection device merely checks whether or not the solder paste is printed, and cannot perform a detailed inspection up to the printing position, thickness and dimensions of the solder paste.

On the other hand, in the case of the latter inspection device, the device itself becomes expensive because X-rays are used.

[0005]

SUMMARY OF THE INVENTION The present invention is intended to solve such a problem, and is a solder paste shape recognizing device having a low-cost structure and capable of accurately recognizing the shape of a solder paste on a printed circuit board. Is intended to be provided.

Another object of the present invention is to solve such a problem, and an object thereof is to provide a solder paste shape recognizing device having an inexpensive structure and capable of detecting the thickness of the solder paste on the printed circuit board. ..

A further object of the present invention is to solve such problems, and it is an object of the present invention to provide a solder paste shape recognizing device which can more accurately judge the quality of a solder paste printed on a printed circuit board.

[0008]

In order to achieve the above-mentioned object, a solder paste shape recognizing device according to a first aspect of the invention has a light source for illuminating the surface of a printed board on which a solder paste is printed, and the illuminated printed board. Image pickup means for color-picking up the surface portion including the solder paste, separation means for separating the color video signal output from the image pickup means into each hue component for each of red, green, and blue, and the separation means And a conversion means for converting each of the red, green, and blue color video signals into multivalued digital image information,
A plurality of storage means for respectively storing the digital image information for each of red, green and blue converted by the conversion means, and the solder from the storage means of at least one of the plurality of storage means according to a preset condition. Image information indicating the shape of the solder paste, the specific image extraction means for extracting pixel-by-pixel digital image information within a specific value or value range corresponding to the paste image, and the digital image information extracted by the specific image extraction means. And a means for outputting as.

In order to achieve the above-mentioned object, the solder paste shape recognizing device of the second invention emits light so that the light applied to the end face of the solder paste printed on the printed board is reflected above the printed board. A ring-shaped light source for irradiating, an image pickup means for picking up an image of a surface portion including the solder paste on the printed board from directly above the printed board, and a shape of the solder paste is recognized from an image picked up by the image pickup means. And means for doing so.

In order to achieve the above-mentioned object, the solder paste shape recognizing device of the third invention is provided with a light source for irradiating the printed portion of the solder paste on the printed board with slit light in an oblique direction with respect to the surface of the solder paste. An image pickup means for picking up an image of a surface portion including the solder paste on the printed board from directly above the printed board; and the slit light on the printed board and the solder paste from an image picked up by the image pickup means. And a means for determining the thickness of the solder paste based on the length of the deviation.

A solder paste shape recognizing device according to a fourth aspect of the present invention is arranged above a pad of a printed circuit board, and has an image pickup means for picking up an image of the solder paste printed on the pad, and a surface of the solder paste on the printed circuit board. On the printed circuit board, a light source is arranged so that the light reflected from the end surface of the solder paste by irradiating light from an oblique direction is received by the image pickup means with emphasis on at least other portions. In the storage unit in which the reference data indicating the position and size of the pad in, and a contour image of the imaging unit obtained by the light emitted from the light source, a unit for calculating the print size of the solder paste, The print size of the solder paste calculated by the calculation means is compared with the reference data of the pad taken out from the storage unit, and The solder paste on the pads is equipped with means for determining whether or not print properly, and means for notifying the result determined by the determining means.

[0012]

In the solder paste shape recognizing device of the first invention, the brightness distribution (histogram) for each of red, green and blue of the image of the printed board, the solder paste and other objects existing on the printed board is checked in advance. Then, it is determined which color luminance distribution correctly represents the luminance concentrated portion of the image of the solder paste without being affected by the luminance distribution of the image of the other portion, and based on this determination result, the specific image extracting means is determined. Specify the extraction destination of the image information. Along with this, the width of the signal value corresponding to the brightness width of the image of the solder paste is set as a condition for extracting the image information from the storage means of the extraction destination.

In the actual processing, first, the image pickup means images the state of the solder paste printed portion on the printed circuit board in color, and the separating means separates this color video signal into each hue component of red, green and blue. To do. The separated red, green, and blue color image signals are converted into multivalued digital image information, and then stored in corresponding storage means. After that, the specific image extraction means extracts the digital image information within a specific value or value range corresponding to the image of the solder paste from the storage means of the corresponding color according to the set conditions, and extracts the extracted digital image information. It is output as image information showing the shape of the solder paste.

Therefore, according to the present invention, it is possible to accurately extract and recognize the image of the solder paste from the captured whole image on the printed circuit board.

In the solder paste shape recognizing device of the second invention, by capturing strong reflected light from the end portion of the solder paste printed on the printed circuit board by the image pickup means, only the outline of the solder paste can be detected in other portions. It is possible to obtain a shape recognition result that is brighter and more prominent.

In the solder paste shape recognition device of the third invention, the slit light obliquely applied to the printed portion of the solder paste on the printed circuit board is captured by the image pickup means. And from this image, find the length of the deviation of the slit light irradiation line between the printed board and the solder paste,
The thickness of the solder paste can be calculated based on the length of this deviation.

In the solder paste shape recognizing device of the fourth invention, the solder paste printing portion on the printed circuit board is irradiated with light from an oblique direction, and the outline image of the solder paste is captured by the image pickup means. Then, from the contour image captured by this imaging means, calculate the print size of the solder paste, compare the reference data of the pad from the storage unit, and determine whether the solder paste is properly printed, This determination result is notified.

That is, by comparing each standard size of the pad whose position is determined on the printed circuit board with the size of the printed solder paste (printing size), it is possible to finely judge the quality of the printed state of the solder paste. As a result, the quality of the solder paste printed state can be determined more accurately than before.

[0019]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a view showing the arrangement of a solder paste shape recognition apparatus according to an embodiment of the present invention.

As shown in the figure, this solder paste shape recognizing device has a ring-shaped light source 3 for uniformly irradiating the surface of a printed board 2 on which a solder paste 1 is printed with light.
A color camera 4 that captures a color image of a portion where the solder paste 1 is printed from directly above the printed circuit board 2, and an image processing device 5 that processes the color image captured by the color camera 4 to recognize and display the planar shape of the solder paste 1. It consists of

FIG. 2 is a block diagram showing the arrangement of the image processing section in the image processing apparatus 5.

In the figure, reference numeral 11 is a separation circuit for separating the color video signal transferred from the color camera 4 into hue components for each of red, green and blue. 12a, 12b, 12c
Is an A / D converter for converting each of the red, green, and blue color video signals separated by the separation circuit 11 into multivalued digital image information. Reference numerals 13a, 13b, and 13c are an R buffer memory, a G buffer memory, and a B buffer memory, respectively, which store the image information digitally multivalued by the A / D converters 12a, 12b, and 12c. 14
Is a specific image extraction unit that extracts digital image information within a specific value or within a specific value corresponding to the image of the solder paste 1 in pixel units from any of the three buffer memories 13a, 13b, 13c according to preset conditions. Is.
Reference numeral 15 is a memory for storing the digital image information extracted by the specific image extracting unit 14 as a plane image of the solder paste 1 on the printed board 2.

Next, the principle of this device will be described.

FIG. 3 shows a printed circuit board a and a solder paste b.
9 is a graph showing a luminance distribution (histogram) for each of red, green, and blue of the pad portion c. In the graph, the horizontal axis represents luminance and the vertical axis represents the frequency of appearance of luminance. For reference, the brightness distribution of a monochrome image is also shown in FIG. As described above, in the brightness distribution of the black and white image, there is not much difference between the printed board a, the solder paste b, and the pad portion c in the areas where the brightness of each image is concentrated. On the other hand, in the case of the luminance distribution of each image of red, green, and blue, in the case of this example, the respective luminances are concentrated among the printed board a, the solder paste b, and the pad portion c particularly in the luminance distribution of the red image. It can be seen that there is a clear difference in the part.

Therefore, in this embodiment, paying attention to such a point, the brightness distribution of which color accurately represents the brightness concentrated portion of the image of the solder paste b without being influenced by the brightness distribution of the image of the other portion. It is determined whether the image information is extracted from which buffer memory based on this determination result as a setting condition to the specific image extraction unit 14.
Along with this, as a condition for extracting the image information from the buffer memory, the width of the signal value corresponding to the width where the brightness of the image of the solder paste b is concentrated is set. In the actual recognition process, the specific image extraction unit 14 selectively extracts the digital image information from the buffer memory according to the above setting conditions. Thereby, the image generation of only the solder paste b is realized.

Next, the operation of the solder paste shape recognition apparatus of this embodiment will be described with reference to FIGS. 1 and 2.

When the surface image on the printed circuit board 2 illuminated by the light of the light source 3 is captured by the color camera 4, the color image signal is input to the image processing device 5. The color video signal input to the image processing device 5 is first separated into each hue component for each of red, green and blue by the separation circuit 11.
Thereafter, the red, green, and blue color image signals are converted into multi-valued digital image information for each pixel by the A / D converters 12a, 12b, and 12c, and then the corresponding R buffer memories 13a and G, respectively. It is stored in the buffer memory 13b and the B buffer memory 13c. After that, the specific image extraction unit 1
4 extracts digital image information within a specific value or value range corresponding to the image of the solder paste 1 in pixel units from the corresponding buffer memory according to the above-mentioned setting conditions. The extracted digital image information is stored in the memory 15 and displayed as a plane image of the solder paste 1.

Thus, according to the solder paste shape recognition apparatus of this embodiment, only the image of the solder paste 1 is extracted from the color images captured by the color camera 4, and this is obtained as the shape recognition result of the solder paste 1. You can

Next, another embodiment of the present invention will be described.

FIG. 5 is a diagram showing the structure of the solder paste shape recognition apparatus of this embodiment.

As shown in the figure, this solder paste shape recognizing device has a ring-shaped light source 23 which uniformly irradiates the surface of the printed board 22 on which the solder paste 21 is printed with light from the surroundings, and a true shape of the printed board 22. It comprises a camera 24 for picking up an image of the portion printed with the solder paste 21 from above, and an image processing device 25 for processing the image picked up by the camera 24 to recognize and display the outline of the solder paste 21.

In the figure, A indicates the light emitted from the light source 23 to the edge portion of the solder paste 21, and B indicates the reflected light of the light applied to the edge portion. Light source 2
3 is arranged by selecting its height and position so that the light A applied from the light source 23 to the edge portion of the solder paste 21 is reflected in the direction of the camera 24 arranged right above the printed circuit board 22.

Therefore, at this time, the reflected light from the edge portion of the solder paste 21 is captured by the camera 24 as light stronger than the reflected light from other portions. Therefore, by sending the video signal at this time to the image processing device 25, the image processing device 25 can obtain a black-and-white image in which the contour of the solder paste 21 stands out brighter than other portions.

Thus, according to the solder paste shape recognizing apparatus of this embodiment, the camera 24 captures the strong reflected light from the edge portion of the solder paste 21, so that the outline of the solder paste 21 is made brighter than the other portions. You can get a black and white image. Therefore, the shape of the solder paste 21 can be accurately recognized from this black and white image.

Next, still another embodiment of this embodiment will be described.

FIG. 6 is a diagram showing the structure of the solder paste shape recognition apparatus of this embodiment.

As shown in the figure, this solder paste shape recognizing device has a ring-shaped light source 33 for uniformly irradiating the surface of the printed board 32 on which the solder paste 31 is printed with light from the surroundings, and the printed board 32. Solder paste 3
Two slit light sources 34 and 35 which irradiate the slit light A and B obliquely to 1 and a camera 3 which captures an image of a portion where the solder paste 31 is printed from directly above the printed circuit board 32.
6 and an image processing device 37 for recognizing the outline and thickness of the solder paste 31 by processing the image captured by the camera 36.
It consists of The two slit light sources 34, 3
5 is the solder paste 3 for each slit light A, B
They are arranged in such a position that they intersect each other at a right angle.

In the figure, 38 is the image processing apparatus 3.
7 is a display screen displaying the image processing result of No. 7. In the display contents of the display screen 38, C is the solder paste 31.
Shows the outline of. That is, this reflects the strong reflected light from the edge portion of the solder paste 31, as described in the previous embodiment. Further, La and Lb are irradiation lines of the slit lights A and B, respectively. Since each slit light A, B is applied to the surface of the solder paste 31 from an oblique direction, each slit light A, B
B irradiation lines La and Lb are solder paste 3 respectively.
1 and the printed circuit board 32 are displaced by the length of d.

In this embodiment, the image processing device 37 determines the displacement length d of the irradiation lines La and Lb of the slit lights A and B generated between the solder paste 31 and the printed board 32. , Based on this length d, the solder paste 31
Measure the thickness of. That is, the thickness H of the solder paste 31 is H when the irradiation angle of the slit lights A and B is θ.
= D × tan θ. further,
In this embodiment, since two slit lights A and B are used, the height H of the solder paste 31 is determined in two ways, and the average value of these is obtained as the final measurement result.

Measured thickness H of solder paste 31
Is numerically displayed on the display screen 38 on the spot. Alternatively, a pass / fail judgment is made on the obtained thickness H of the solder paste 31, and the result is displayed on the display screen 38.

Next, another embodiment of this embodiment will be described.

FIG. 7 is a block diagram showing the structure of a solder paste shape recognition apparatus according to an embodiment of the present invention.

As shown in the figure, this solder paste shape recognizing device has a camera 44 for picking up an image of the surface of the pad 43 on which the solder paste 42 is printed on the printed circuit board 41, and the solder paste 42 and the pad 43. A ring-shaped light source 45 that uniformly irradiates the surroundings with light
And the solder paste 42 printed on the pad 43 based on the image captured by the camera 44 with the light from the light source 45.
And an image processing device 46 that performs the inspection. The camera 44 has, for example, a CCD element or the like arranged in a light receiving section (image pickup section), and can transfer a picked-up image as an image signal to the image processing apparatus 46.

In the figure, A indicates the light emitted from the light source 45 to the solder paste 42 and the pad 43, and B indicates the reflected light which is reflected by the edge portion of the solder paste 42 and enters the camera 44. As described above, the light source 45 irradiates light from a low angle so that light is not reflected by a portion (surface) other than the edge portion, hits each edge portion of the solder paste 42 and the pad 43, and is disposed directly above the pad 43. The height and the position are selected so that the light is received by 44.

FIG. 8 is a block diagram showing the internal structure of the image processing apparatus 46.

In the figure, reference numeral 51 denotes a storage unit which stores so-called reference data such as preset center coordinates of the pad 43 on the substrate 41 and dimension data such as the width of the pad 43. An image processing unit 52 A / D converts the image signal transferred from the camera 44 to obtain a contour image of the solder paste 42. Reference numeral 53 denotes an arithmetic unit, which measures the actual size of the solder paste 42 printed from each pixel of the contour image obtained by the image processing unit 52.
Calculate position etc. Reference numeral 54 denotes a comparison / determination unit that compares the calculated actual size of the solder paste 42 with the reference size of the pad 43 stored in the storage unit to determine whether the printing state of the solder paste 42 is good or bad. Reference numeral 55 is a display unit as a notification means, and the determination result is displayed.

In this solder paste shape recognizing device, since light is emitted from the light source 45 at a low angle, the reflected light from the respective edge portions of the solder paste 42 and the pad 43 is reflected by other portions of the camera 44. The image captured as stronger light and captured by the camera 44 is sent to the image processing device 46 as an analog image signal.

The image signal is input to the image processing unit 52 of the image processing apparatus 46, and the image processing unit 52 obtains a contour image of the solder paste 42 as shown in FIG.

As shown in the figure, in the case of this image, the surface of the solder paste 42 and the surface of the pad 43 are not drawn, and only the contour 61 of the solder paste 42 is brightly emphasized (hereinafter referred to as a contour image). )become.

The data of the contour image is fetched by the arithmetic unit 53. The calculation unit 53 calculates 1 based on the acquired data.
With the pixel size being, for example, 20 μm, the print range of the solder paste 42 (the size of the area surrounded by the outline 61), for example, the horizontal width SX and the vertical width SY of the solder paste 42, are calculated, and the pad 43 on Area (SX × SY) of solder paste 42 and solder paste 42 in
The distance (SX / 2, SY / 2) from the center to the contour 61 is calculated.

As shown in the figure, the comparison / determination unit 54 uses the storage unit 51 as reference data for the pad 43, for example, the distance DX in the horizontal (X) direction from the center of the pad 43 on the substrate 41 and the vertical direction from the center. Distance DY in the (Y) direction and area (PX ×
Each data such as PY) is taken out and calculated by the calculation unit 53 (distance from the center of the solder paste 42 (SX /
2, SY / 2) and area (SX x SY), etc.}.

As a result of this comparison, in the comparison / determination section 54, the respective dimensions of the solder paste 42 are
If it is within the allowable range, for example, 80% or more, the printing state of the solder paste is determined to be appropriate, and if it is less than that, it is determined to be defective, and these determination results are displayed on the display unit 55.

As described above, according to the solder paste shape recognizing device of the present embodiment, by irradiating the solder paste 42 with light from a low angle, the outline of the solder paste 42 is emphasized by the camera 44 to be imaged. , The dimensions of the solder paste 42 (DX, D
Y), (SX, SY), etc. are calculated and compared with the respective standard dimensions of the pad 43. You can inspect the details such as the presence of bridges between them.

That is, on the substrate 41, the reference dimension of the pad 43 whose position is determined in advance is compared with the print dimension calculated from the outline image of the solder paste 42. The quality can be determined more accurately.

[0056]

As described above, according to the solder paste shape recognition apparatus of the present invention, the shape of the solder paste on the printed circuit board can be accurately recognized with an inexpensive structure. Further, the thickness of the solder paste on the printed board can be easily detected. Further, the print state of the solder paste on the printed circuit board can be determined more accurately than before.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a solder paste shape recognition device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of an image processing unit in the image processing apparatus in FIG.

FIG. 3 is a graph showing a luminance distribution for each of red, green and blue of a printed circuit board, a solder paste and a pad portion in a color image.

FIG. 4 is a graph showing a luminance distribution of a printed circuit board, a solder paste and a pad portion in a monochrome image.

FIG. 5 is a diagram showing a configuration of a solder paste shape recognition device according to another embodiment of the present invention.

FIG. 6 is a diagram showing a configuration of a solder paste shape recognition device according to still another embodiment of the present invention.

FIG. 7 is a diagram showing a configuration of a solder paste shape recognition device according to another embodiment of the present invention.

8 is a block diagram showing an internal configuration of the solder paste shape recognition device in FIG. 7. FIG.

9 is a diagram showing an image of a solder paste imaged by the solder paste shape recognition device of FIG. 7.

[Explanation of symbols]

1 ... Solder paste, 2 ... Printed circuit board, 3 ... Ring-shaped light source, 4 ... Color camera, 5 ... Image processing device, 11 ...
Separation circuit, 12a, 12b, 12c ... A / D converter, 1
3a ... R buffer memory, 13b ... G buffer memory,
13c ... B buffer memory, 14 ... specific image extraction unit, 1
5 ... Memory.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinji Saito 2-9 Suehiro-cho, Ome-shi, Tokyo Inside the Ome Plant of Toshiba Corporation (72) Inventor Kazuharu Shimoda 1381 Shinmachi, Ome-shi, Tokyo 1 Toshiba Comp In Computer Engineering Co., Ltd. (72) Inventor, Kazue Migamoto 1381 Shinmachi, Ome City, Tokyo 1st, Toshiba Computer Engineering Co., Ltd.

Claims (4)

[Claims] 1. A light source for illuminating a surface of a printed circuit board on which a solder paste is printed, an image pickup unit for color-imaged a surface portion including the solder paste on the illuminated printed circuit board, and output from the image pickup unit. Color video signals are red, green,
Separation means for separating each hue component for each blue, conversion means for converting each of the red, green, and blue color video signals separated by the separation means into multivalued digital image information, and conversion by the conversion means A plurality of storage means for respectively storing the digital image information for each of the red, green, and blue, and at least one storage means of the plurality of storage means corresponds to the image of the solder paste according to a preset condition. Specific image extraction means for extracting digital image information within a specific value or value range on a pixel-by-pixel basis, and means for outputting the digital image information extracted by the specific image extraction means as image information indicating the shape of the solder paste. A solder paste shape recognizing device comprising: 2. A ring-shaped light source that emits light so that light applied to an end face of a solder paste printed on a printed circuit board is reflected above the printed circuit board, and the printed circuit board from directly above the printed circuit board. A solder paste shape recognition device comprising: an image pickup means for picking up an image of a surface portion including the above solder paste; and a means for recognizing the shape of the solder paste from an image picked up by the image pickup means. 3. A light source for irradiating a printed portion of the solder paste on the printed circuit board with slit light oblique to the surface of the solder paste, and the solder paste on the printed circuit board from directly above the printed circuit board. An image pickup means for picking up an image of the surface portion, and a length of deviation of the slit light between the printed board and the solder paste is obtained from an image picked up by the image pickup means, and the solder is based on the length of the deviation. A solder paste shape recognizing device, comprising: means for determining a paste thickness. 4. The printed circuit board is disposed above the pad,
An image pickup means for picking up an image of the solder paste printed on the pad, and the light reflected on the end face of the solder paste by irradiating the solder paste on the printed board with light from an oblique direction with respect to the surface of the solder paste is at least other part. A light source arranged so as to be emphasized by the image pickup means so as to be received by the image pickup means, a storage section in which reference data indicating the position and size of the pad on the printed circuit board are stored in advance, and the light source is irradiated. A means for calculating the print size of the solder paste from the contour image of the image pickup means obtained by light, the print size of the solder paste calculated by the calculating means, and the reference of the pad taken out from the storage section. Means for comparing the data with the pad to determine whether or not the solder paste is properly printed on the pad; Solder paste shape recognition apparatus characterized by comprising a means for notifying the result determined by.