JP2002158500A - Method for inspecting double-sided mounting board and its equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for inspecting a double-sided mounting board and its equipment wherein a board which is prepared as specimen does not become useless, reduction of cost can be realized and inspection time can be shortened. SOLUTION: Surface specimen image data wherein components are mounted only on the surface of a board are obtained and stored, double-sided perspective image data in a board wherein components are mounted on a surface and a back are obtained and stored, the surface specimen image data are subtracted from the double-sided perspective image data, and perspective image data in the back are obtained as back specimen image data. In a practical inspection board, the surface specimen image data and the back specimen image data are subtracted from double-sided perspective image data in the inspection board, and real image data in the back and the surface of the inspection board are obtained, and quality of mounting state of components is judged from the real image data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the state of electronic components mounted on both sides of a substrate such as a printed circuit board by irradiating X-rays,
For example, the present invention relates to an inspection method and an apparatus for inspecting a soldering state and a mounting state of a component.

[0002]

2. Description of the Related Art As a conventional method for inspecting a soldering state of a board having electronic components mounted on both sides, there is a method disclosed in Japanese Patent No. 2,945,537, for example. This method irradiates X-rays to a board on which the components are soldered on the front and back sides, obtains X-ray fluoroscopic image data, and then, from the fluoroscopic image data, the components are normally soldered only to the front surface or the back surface. This is a method of judging the quality of soldering based on a comparison between image data obtained by subtracting X-ray fluoroscopic image data of a substrate and a fluoroscopic image of a substrate in which components are normally soldered only on the back or front surface.

[0003] That is, this soldering inspection method comprises, as image data, first image data of a substrate having components soldered on both sides, and second image data and a back surface normally soldered only on the front surface or the back surface. Or, three image data of the third image data normally soldered only to the surface is required, and a difference between the second image data and the third image data is obtained from the first image data, This is a method of making a pass / fail decision by comparing the fourth and fifth image data obtained by the difference with preset image data.

[0004]

By the way, in the above-mentioned conventional example, the second and third image data are differentiated from the first image data of the inspection board having parts mounted on both sides. Because it is a judgment, two boards are required for inspection of the board with components mounted on the front side only and the board with components mounted on the back side only, and the two boards are soldered properly. Since it is necessary to manufacture the two boards, it is troublesome to manufacture the two boards, and the board on which the components are mounted first on the side on which the components are mounted later mounts the components on the opposite side after the inspection. However, there is a problem that half of the substrates manufactured for a sample are wasted.

[0005] In the specification of the conventional example, it is stated that design data obtained in design may be input as numerical values instead of the two substrates for inspection. It is difficult to create data, and the actual board for inspection and the numerical data do not always match. If such numerical data is used for inspection,
There is a problem that an error occurs in the inspection result.

An object of the present invention is to solve the above-mentioned problem. The purpose of the present invention is to manufacture only a substrate having components mounted only on the surface, which is performed in a normal substrate mounting, as a sample substrate. In other cases, it is sufficient to prepare a normal double-sided mounting board.Since a board with components mounted on the front side can also have components mounted on the back side in a later process, the board prepared for the sample is It is an object of the present invention to provide a double-sided mounting board inspection method and apparatus which can reduce costs without wasting and shorten the inspection time.

[0007]

SUMMARY OF THE INVENTION A method for inspecting a double-sided board according to the present invention does not achieve the above-mentioned object. The method comprises obtaining and storing surface sample image data in which components are mounted only on the surface of a board. Then, the two-sided perspective image data on the substrate on which the components are mounted on the front and back sides are obtained and stored, and the front side sample image data is subtracted from the two-sided perspective image data to obtain the back side perspective image data to obtain the back side sample image. With the data, in the actual test board, by subtracting the front side sample image data and the back side sample image data from the double-sided perspective image data on the test board, to obtain real image data of the back and front sides of the test board, It is characterized in that the quality of the component mounting state is determined from the actual image data.

The surface sample image data is obtained by calculating an average value of the perspective image data of a plurality of substrates having components mounted on only the surface, thereby obtaining surface sample image data.
The back surface sample image data is an image data of an average value of the back surface sample substrate obtained by calculating a difference from the front surface sample image data from the double-sided perspective image data on the plurality of substrates on which components are mounted on both surfaces. And

Means of the double-sided mounting board inspection apparatus of the present invention includes:
X-ray imaging means for irradiating a substrate with X-rays to obtain a fluoroscopic image including components mounted thereon, and image conversion for AD-converting the fluoroscopic image obtained by the X-ray imaging means to obtain fluoroscopic image data Means, a memory for storing, as surface sample image data, fluoroscopic image data of a substrate having components mounted on only the surface, and a memory for storing fluoroscopic image data with components mounted on both surfaces obtained by the image conversion means. Calculating means for performing a difference between the front side sample image data stored in the memory from the perspective image data in which components are mounted on both sides stored in the memory, and the back side perspective image data obtained by the calculating means. The difference between the memory storing the backside sample image data and the front side sample image data stored in the memory from the double-sided perspective image data on the inspection board is used to calculate the backside image data. And a memory for storing the backside image data obtained by the calculating means as actual backside image data, and performing a difference between the backside sample image data stored in the memory from the double-sided perspective image data on the inspection board. Calculating means for obtaining front side image data; a memory for storing the front side image data obtained by the calculating means as front side real image data; It is provided with.

The memory for storing the front side sample image data stores perspective image data obtained by averaging a plurality of pieces of perspective image data, and the memory for storing the back side sample image data includes a component on both sides. And averaged perspective image data obtained by obtaining a difference from the surface sample image data from the double-sided perspective image data on a plurality of substrates on which is mounted.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a double-sided board inspection apparatus according to the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes an X-ray irradiator, 2 denotes an X-ray imaging device that captures an image transmitted through a printed circuit board P (hereinafter, simply referred to as a substrate), and 3 denotes an AD converter that converts an image from the X-ray imaging device 2. Image conversion means for converting into a digital image signal via
2 is a control means described in detail in FIG. 2, 5 is a pass / fail determination means for performing a pass / fail judgment of a soldering state or a mounting state of a mounted component using image data of the front and back surfaces of the inspection board obtained by the control means, Reference numeral 6 denotes a display means such as a CRT for displaying which part is defective when the pass / fail determination means determines that the part is defective.

Next, the control means 4 will be described in detail.
A memory for storing perspective image data captured by the line irradiation device 1 and converted by the image conversion unit 3;
Calculating means for calculating an average value of a plurality of perspective image data; calculating means for calculating a difference between the sample image data on the front and back surfaces averaged by the calculating means and the perspective image data on the inspection board having components mounted on both sides; (Not shown).

Next, the operation based on the above configuration will be described with reference to FIG.
This will be described with reference to a flowchart of First, in order to manufacture a substrate P which is a substrate to be inspected having components mounted on both sides, the components are mounted on the front surface by a component mounting apparatus and soldered through a furnace, and then, similarly, the components are mounted on the back surface and passed through the furnace. Solder.

Here, when the component mounting apparatus is set such that the components are soldered to the front surface and then to the rear surface (in a general component mounting device, the components are mounted in the order of the front surface and the rear surface). In the case of a board on which components are mounted and soldered only on the back side, it is impossible to mount components on the front side using a component mounting apparatus.

First, a substrate P on which components are mounted only on the front surface side of a plurality of substrates P is arranged between the X-ray irradiator 1 and the X-ray imaging device 2, and the X-ray irradiator 1 is activated. When the substrate P is irradiated with X-rays, a fluoroscopic image of the substrate P is obtained by the X-ray imaging device 2.

The fluoroscopic image from the X-ray imaging apparatus 2 is converted into a digital signal by the image conversion means 3 and stored in the memory as front-side fluoroscopic image data. The fluoroscopic image data is stored in the memory.

Next, a plurality of surface perspective image data are averaged by the calculating means, and the averaged surface perspective image data is stored in a memory as surface sample image data a (see the photograph of FIG. 3) (step). S1).

Next, a plurality of actual inspection boards having components mounted on both front and back sides are prepared, and the perspective image data b of each actual inspection board is compared with the X-ray irradiator 1 and X-ray imaging apparatus 2 described above. The perspective image data b (see the photograph in FIG. 4) of the double-sided mounting board is stored in the memory (step S2).

Next, in the calculating means, from the perspective image data of the substrate P having the components mounted on both sides stored in the memory, the surface sample image data having the components mounted only on the surface stored in the memory is obtained. Calculate the difference,
The fluoroscopic image data on the back side of the substrate P as the inspection substrate is obtained and stored in the memory.

The back side perspective image data is repeatedly obtained by the number of the prepared double-sided mounting boards, and after all the operations are completed, the back side perspective image data is averaged by the calculating means. Then, the averaged image data is stored in the memory as the back surface sample image data c (see the photograph in FIG. 5) (step S3). In the photograph of FIG. 5, there is a part that is not completely extracted in the lower part of the image, because a part that blocks X-rays is mounted on the surface.

Next, a substrate having components mounted on both sides to be inspected is disposed between the X-ray irradiator 1 and the X-ray imaging device 2, and the fluoroscopic image data d is temporarily stored in a memory (step S4). ), The perspective image data d stored in this memory
Then, the difference from the back side sample image data a is calculated by the calculating means, and the resulting image data e is stored in the memory (step S5).

Next, in the same manner as described above, the difference between the surface sample data c and the fluoroscopic image data d is calculated by the calculation means, and the resulting image data f is stored in the memory (step S6).

Then, the quality determination means determines whether the soldering state or the mounting state of the component in the image data on the front side and the back side of the board P, which is the inspection board obtained by such a procedure, is normal or defective. 5 (step S7), and if it is determined that a defect has occurred, the CR
It is displayed on the display means 6 such as T.

As the fluoroscopic image data on the front side as a sample, an average value of a plurality of substrates in which components are mounted only on the surface of the substrate has been described.
As the front side perspective image data, data obtained by inputting design data as numerical values may be stored in a memory.

Further, in the above-described embodiment, in order to obtain back-side sample image data, components mounted on both sides are used.
After the difference between the image data of the substrate for each sheet and the image data of the front surface sample is performed, the back surface sample image data is obtained from the average value of the difference. After obtaining the average value of the data, the difference between the average value and the surface sample image data may be calculated to obtain the back surface sample image data.

[0026]

As described above, the present invention obtains perspective image data of a substrate having components mounted only on the front surface and converts it into surface sample image data. Obtaining and storing image data, subtracting the front surface sample image data from the double-sided perspective image data to obtain the rear surface perspective image data and forming the back surface sample image data,
In an actual inspection substrate, the front surface sample image data and the back surface sample image data are subtracted from the double-sided perspective image data of the inspection substrate to obtain actual image data of the back surface and the front surface of the inspection substrate. Since the quality of the mounted state of the components is determined from the above, the board with the components mounted on the back side as in the conventional example is not wasted, and the soldering state and the mounting state of the components of the double-sided mounted board are not changed. The inspection can be performed with high accuracy, and the inspection time can be reduced.

The surface sample image data is obtained as an image data of a surface sample substrate by calculating an average value of perspective image data of a plurality of substrates having components mounted only on the surface.
Also, since the back sample image data is the image data of the average value of the back sample substrate obtained by calculating the difference from the front sample image data from the double-sided perspective image data on the plurality of substrates on which the components are mounted on both surfaces. Further, the present invention has the effect that the inspection of the soldering state and the mounting state of the components of the double-sided mounting board can be performed with higher accuracy.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing a double-sided board inspection apparatus according to the present invention.

FIG. 2 is a flowchart showing an operation.

FIG. 3 is an X-ray photograph of a substrate on which components are mounted only on the surface.

FIG. 4 is an X-ray photograph of a substrate having components mounted on both sides.

FIG. 5 is an X-ray photograph obtained by subtracting the photograph of FIG. 3 from the photograph of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 X-ray irradiation apparatus 2 X-ray imaging apparatus 3 Image conversion means 4 Control means 5 Pass / fail judgment means 6 Display means

Claims (4)

[Claims] 1. Obtaining and storing surface sample image data in which components are mounted only on the front surface of a substrate, and then obtaining and storing double-sided perspective image data of a substrate having components mounted on the front and back surfaces, The front side sample image data is subtracted from the data to obtain the back side perspective image data to make the back side sample image data.In an actual inspection board, the front side sample image data and the back side are obtained from the double side perspective image data on the inspection board. A method of inspecting a double-sided mounting board, characterized by obtaining actual image data of the back and front surfaces of an inspection board by differentiating sample image data, and judging the quality of a component mounting state from the actual image data. 2. The front surface sample image data is obtained by calculating an average value of fluoroscopic image data of a plurality of substrates on which components are mounted only on the front surface to obtain front surface sample image data. 2. The double-sided image data according to claim 1, wherein a difference between the image data of the front surface sample and the image data of the front surface sample is obtained from double-sided perspective image data of a plurality of substrates having components mounted on both surfaces. Mounting board inspection method. 3. An X-ray imaging means for irradiating a substrate with X-rays to obtain a perspective image including parts mounted thereon, and a perspective image obtained by AD-converting the perspective image obtained by the X-ray imaging means. Image conversion means for obtaining data; memory for storing, as surface sample image data, perspective image data of a substrate having components mounted only on the surface; and perspective image data having components mounted on both sides obtained by the image conversion means. A memory for storing the surface sample image data stored in the memory from the perspective image data in which the components are mounted on both sides stored in the memory; and a back surface obtained by the arithmetic unit And the difference between the front side sample image data stored in the memory from the double side perspective image data on the inspection board Calculating means for obtaining backside image data, a memory for storing the backside image data obtained by the calculating means as actual backside image data, and a backside sample image data stored in the memory from the double-sided perspective image data on the inspection board. Calculating means for obtaining the front surface image data by performing the difference of the above, a memory for storing the front surface image data obtained by the calculating means as real front surface image data, and judging whether the component mounting state is good or bad from the front and back real image data. A double-sided mounting board inspection apparatus, comprising: a pass / fail determination unit. 4. The memory for storing the front side sample image data stores perspective image data obtained by averaging a plurality of pieces of perspective image data, and the memory for storing the back side sample image data includes components on both sides. 4. The double-sided board inspection according to claim 3, further comprising: storing an averaged perspective image data obtained by calculating a difference between the two-sided perspective image data and the surface sample image data on the plurality of substrates on which is mounted. apparatus.