JPH07134019A - Method for specifying inspection position in x-ray soldering inspection - Google Patents

Abstract

PURPOSE:To find a desired inspection position for conducting a soldering inspection from an unmounted substrate, and also to keep corresponding to a double side mounted substrate. CONSTITUTION:In a fixed position of an X-ray soldering inspection device 10 in which a mounted board for conducting a soldering inspection is disposed, an unmounted board 2 of a state in which a part is not put on the mounted board is disposed, and an X-ray transmission image of the board 2 is taken. The X-ray transmission image of the board 2 is effected binarization by a land image extracting part 22 of an inspection position specifying device 1, and a soldering land is extracted. Regarding each soldering land extracted, the central coordinates are found by an arithmetic processing part 21, and also a part position to each soldering land is found from the data of a fitting position of the part for the soldering land previously prepared, the position of a soldering part is detected from the central coordinates of the soldering land and the part position, and this is outputted to the X-ray soldering inspection device 10 as the soldering inspection position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray for inspecting the quality of a soldered portion by irradiating an X-ray on a mounting board having components mounted on the board by soldering and detecting the distribution of the amount of transmitted light. The present invention relates to an inspection position specifying method for specifying a position of a soldering portion to be inspected in a soldering inspection.

[0002]

2. Description of the Related Art By irradiating a mounting board with X-rays and detecting the distribution of the X-ray dose transmitted through the mounting board with an X-ray detector, the soldered portion of the mounting board can be inspected. At this time, it is necessary to accurately specify the position of the soldering portion that irradiates the X-ray, that is, the inspection position, and teach it to the inspection device. As a conventional method of teaching the inspection position to the inspection device, a method of creating inspection position data from mounter data including data of mounting positions of components on a board, or soldering part data of each component obtained from the mounter data Like the method in which the operator manually inputs, the inspection position is specified based on the mounter data, the mounting board is irradiated with X-rays, and the position of the soldering part is detected from the transmission amount distribution. A method is known in which the inspection position is specified from the mounting board itself which is the inspection position. As a method of irradiating the mounting board with X-rays to specify the inspection position,
There is a method disclosed in JP-A-3-68845.
This method creates a projection distribution by adding images in the lead arrangement direction and the lead longitudinal direction of the soldered component from the X-ray transmission image, detects the soldering portion from this projection distribution waveform, and determines the center of the projection position. Is specified as.

[0003]

However, in the method based on the mounter data in the above-mentioned prior art, information such as the center coordinates of the parts required for the inspection and the mounting angle is extracted from the mounter data, and the extracted information is used by the inspection device. In order to make inspection position data that can be operated, there is a problem that conversion programs for various different mounters must be created. In addition, the method of manually inputting by the operator is a laborious task of inputting the position / angle data of each part one by one, which requires a lot of work time and may cause an erroneous input. Further, the method of identifying the inspection position from the mounting board has a problem that the detection position is erroneous when the component position is displaced or the soldering is defective. Therefore, the present invention is an X-ray for identifying an inspection position by obtaining an accurate position and shape of a soldering land by image processing from a state before a component is placed on a board, that is, an X-ray transmission image of an unmounted board. An object is to provide a method for specifying a soldering inspection position.

[0004]

In order to achieve the above object, the first method adopted by the present invention is that an X-ray is mounted on a mounting board on which a component is attached by soldering to a soldering land formed on the board. In the method of identifying the inspection position in the X-ray soldering inspection, the soldering inspection is performed by irradiating the soldering land and determining the quality of the soldering portion from the transmission amount distribution of the X-rays transmitted through the soldering portion on the soldering land. The board in a state where no component is placed on the mounting board is set at a predetermined position of the X-ray soldering inspection device for performing the X-ray transmission image capturing by irradiating the board with the X-ray. The transmission image is binarized at a predetermined binarization level to create a binarized image in which soldering lands are extracted, a required soldering land is designated in the binarized image image, and the inspection target soldering is performed. Find the center coordinates of the land, It is a specific method of inspecting position in the X-ray soldering inspection and obtaining the mounting position and mounting direction of the part to be soldered on 査 target soldering land. A second method adopted by the present invention is to irradiate a mounting board, on which a component is attached by soldering, to a soldering land formed on one side or both sides of the board, and to irradiate the mounting land on the soldering land. In a method of identifying an inspection position in an X-ray soldering inspection for determining the quality of the soldering portion based on an X-ray transmission amount distribution transmitted through the soldering portion, the method is set at a predetermined position of an X-ray soldering inspection device for performing the soldering inspection. An image including a required soldering land in the X-ray transmission image is set by setting a substrate on which no component is placed on the mounting board, irradiating the substrate with X-rays, and capturing an X-ray transmission image. An area is designated, and the image data of the designated image area is input to an inspection position detection neural network in which the desired inspection position on the soldering land is learned in advance as teacher data, and the image area is input. It is a specific method of inspecting position in the X-ray soldering inspection and detecting the definitive the desired inspection position. In the above method, when the soldering lands on both sides of the board are overlapped in the image area, the image data of the image area is input to a separate neural network in which the shape of the soldering land is learned in advance as teacher data. Then, only the required soldering land can be extracted.

[0005]

According to the first method of the present invention, the component is placed on the mounting board at a predetermined position of the X-ray soldering inspection apparatus on which the mounting board to be subjected to the X-ray soldering inspection is arranged prior to the inspection. An unmounted board is placed and an X-ray transmission image of the soldering land formed on the board is captured. Since the unmounted board is in a state where the circuit pattern including the soldering land is formed on the board only, when the X-ray transmission image is binarized at a predetermined binarization level, only the circuit pattern is extracted. You can Therefore, the soldering lands are extracted from the binarized image, the soldering lands to be inspected are designated, the center coordinates of the soldering lands are obtained, and the mounting position of the component to the previously prepared soldering lands is determined. The position of the component to be attached to the specified soldering land is obtained from the data. The inspection position is specified from the detected position of the soldering land and the position of the component. According to the second method of the present invention, when the density image of the soldering land is low in the X-ray transmission image of the unmounted board and the outline is unclear and it is difficult to accurately detect the shape of the soldering land, each soldering is performed in advance. By inputting the image data of the image area including the specified soldering land to the neural network that learned the center coordinates on the soldering land, the center coordinates can be detected from the soldering land image with an unclear contour. . Also, when the board is for double-sided mounting,
There may be a case where the soldering land on the opposite surface overlaps the designated soldering land. In this case, the image data of the image area in which the soldering land has overlapped is separated neural network in which the shape of the soldering land is learned in advance. By inputting to, the required soldering land can be separated from the image in which the overlap occurs.

[0006]

Embodiments of the present invention will be described below with reference to the accompanying drawings for the understanding of the present invention. still,
The following example is an example embodying the present invention and does not limit the technical scope of the present invention. Figure 1
2 is a block diagram showing the configuration of an embodiment to which the inspection position specifying method according to the first embodiment of the present invention is applied, and FIG. 2 is a flowchart showing the procedure of the first embodiment method. In Figure 1, X
The wire soldering inspection device 10 is an XY for positioning the mounting substrate 2a, which is placed to perform a soldering inspection, at a predetermined position.
The table 11 is provided with an X-ray source 12 and an X-ray detector 13 which are arranged with the XY table 11 interposed therebetween. X
The X-rays emitted from the radiation source 12 pass through the mounting substrate 2a, and the amount of transmission is detected by the X-ray detector 13. The X-ray transmission amount data is sent to the image processing unit 16 and the X-ray transmission amount distribution data is calculated. This transmission amount distribution data is calculated by computer 1.
Then, the quality of the detected shape of the soldered portion is judged. The computer 19 performs the above processing,
The X-ray controller 14 is operated to control the X-ray source 12, and the XY table controller 15 is operated to control the positioning of the XY table 11. In the X-ray soldering inspection device 10, accurate positioning of the XY table 11 is required to irradiate the soldering portion to be inspected with X-rays, and especially for the recent downsized and high-density boards. On the other hand, high-precision positioning is important. An inspection position specifying device 1 is connected to the X-ray soldering inspection device 10 in order to accurately specify the position of the soldering portion to be inspected.

The inspection position specifying device 1 image-processes an X-ray transmission image stored in the board image storage unit 3 for storing the image data input from the image processing unit 16. A land image extraction unit 22 for extracting an image of a soldering land, a display 17 for displaying an image of the extracted soldering land, and an input device 18 such as a mouse for designating a soldering land to be inspected from the display image. An inspection position designating unit 5 provided, an arithmetic processing unit 21 for performing an arithmetic process for identifying a soldering inspection position on the soldering land designated by the inspection position designating unit 5, and storing the identified inspection position data. The inspection position data storage unit 9 is provided. FIG. 2 shows a procedure of a method for specifying a soldering inspection position using the inspection position specifying device 1 described above.
It will be described based on the flowchart shown in FIG. In the figure, T1, T2 ... Are step numbers indicating the procedure.

First, the board 2 (unmounted board) in a state where no components before being manufactured are mounted on the mounting board 2a to be inspected is placed on the XY table 11 of the X-ray soldering inspection apparatus 10. The X-ray source 12 irradiates X-rays, and the X-ray transmission amount data detected by the X-ray detector 13 is transferred to the image processing unit 16
By inputting to, an X-ray transmission image of the substrate 2 based on the X-ray transmission amount distribution data can be obtained. (T1). This image is input from the image processing unit 16 to the board image storage unit 3 and stored therein, so that the following inspection position specifying operation is executed using this image. The X-ray transmission image of the substrate 2 is read from the substrate image storage unit 3 and the land image extraction unit 22 binarizes the image at a predetermined binarization level to convert the X-ray transmission image into a binary image. (T
2). This binarization process is performed only on the circuit pattern due to the difference in the X-ray transmission amount between the portion of the substrate material forming the substrate 2 and the portion of the circuit pattern including the soldering lands formed on the surface of the substrate material. And a circuit pattern having a smaller amount of X-ray transmission than that of only the substrate material, that is, a soldering land is extracted by setting a predetermined binarization level to obtain a binarized image.

Next, the binarized image obtained by extracting the soldering lands is displayed on the display 17, and the soldering lands to which the components are attached are designated by the input device 18 (T3). The binarized image is input to the arithmetic processing unit 21, and the center coordinates of the designated soldering land are calculated by designating the soldering land (T4). The arithmetic processing unit 21 stores in advance the layout data of the parts for each soldering land, and based on the calculated position data of the soldering land, the position (center coordinate) of the part to be mounted at the predetermined position of the soldering land. And mounting angle)
Is calculated (T5) and compared with the stored arrangement data (T6). When the calculated position data of the parts is different from the stored placement data, the placement data is corrected (T7). By the above processing, the position of the soldering land for inspecting the soldering portion is measured from the X-ray transmission image and the position of the component attached thereto is determined. Therefore, the position of the soldering land and the position of the component are determined. The position of the soldering portion, that is, the soldering inspection position is specified from the. The above process is repeated until the designated soldering lands run out (T8), and the obtained inspection position data is sequentially stored in the inspection position data storage unit 9. The data stored in the inspection position data storage unit 9 is sent to the computer 17 of the X-ray soldering inspection apparatus 10, and the mounting board 2a placed on the XY table 11 moves to the inspection position based on this data. Then, the soldered portion is inspected.

Next, a second embodiment of the present invention will be described. The same elements as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. This embodiment is a double-sided mounting in which a circuit pattern is formed on both surfaces of the target board 2 when only the soldering lands formed on the board 2 by the binarization process are extracted in the first embodiment. In the case where the difference is in the amount of X-ray transmission between the soldering land portion and the portion of only the substrate material cannot be clearly detected due to the state of the substrate 2 or the state of the X-ray soldering inspection device 10. The method employs a means for detecting the center coordinates of the soldering land by the pattern recognition function of the neural network. That is, when the board 2 is for double-sided mounting, if the soldering lands on the front and back sides overlap,
The shape of the soldering land at the overlapping portion cannot be extracted by the method of the first embodiment. Further, since the X-ray transmission image is a grayscale image, when the X-ray transmission cannot be clearly obtained, the density of the soldering land is not constant and the shape of the soldering land cannot be accurately extracted. When the shape of the land becomes ambiguous, it can be dealt with by adopting the method of this embodiment.

FIG. 3 is a block diagram showing the construction of an embodiment to which the inspection position specifying method according to the second embodiment of the present invention is applied, FIG. 4 is a flow chart showing the procedure of the embodiment method, and FIG. 5 is an embodiment. 6 is a schematic diagram showing an example of an X-ray transmission image of a substrate according to the present invention, FIG. 6 is a schematic diagram showing a schematic configuration of a separation neural network according to an embodiment, and FIG. 7 is a schematic diagram showing a schematic configuration of a position detection neural network according to the embodiment. FIG. 8 is a schematic diagram showing setting of a desired inspection position to be learned by the position detection neural network. In FIG. 3, the X-ray soldering inspection device 10 has the same configuration as that of the first embodiment, and the inspection position specifying device 20 is connected thereto. The inspection position identifying device 20 displays the board image storage unit 3 that stores the image data input from the image processing unit 16 and the X-ray transmission image stored in the board image storage unit 3 on the display 17 to display the inspection target. For position identification and front / back separation by controlling the inspection position designating unit 5 having an input device 18 such as a mouse for designating a soldering land, and controlling each neural network described later based on the designation information of the inspection position designating unit 5. In order to detect a desired inspection position on the soldering land, an arithmetic processing unit 4 for performing the above-mentioned arithmetic processing, a separation neural network 6 for separating the front and back soldering lands from a board having soldering lands formed on both sides. X direction position detection neural network 7 and Y direction position detection neural network 8 and the inspection position data for storing the specified inspection position data. Is constructed and a storage unit 9.

The procedure of the method for specifying the soldering inspection position using the inspection position specifying device 1 will be described below with reference to the flowchart of FIG. S1 and S2 in FIG.
... is a step number indicating a procedure. First, the board 25 in which no components before being manufactured on the mounting board 25a to be inspected are placed is placed at a predetermined position on the XY table 11 of the X-ray soldering inspection apparatus, and the X-ray is inspected. Source 12
The X-ray transmission image of the substrate 25 is obtained in the image processing unit 16 by irradiating the X-rays from (S1). The X-ray transmission image is sent to and stored in the board image storage unit 3, and the following inspection position specifying operation is executed based on the stored image. When the board 25 is a board for double-sided mounting, the X-ray transmission image stored in the board image storage unit 3 is an image of a circuit pattern including soldering lands as shown in FIG. Display of wiring patterns etc. is omitted). In FIG. 5, the portion hatched by the solid line is the front side soldering land, and the portion hatched by the dotted line is the back side soldering land. The X-ray transmission image stored in the board image storage unit 3 is input to the arithmetic processing unit 4 and displayed on the display 17 of the inspection position designating unit 5. Therefore, the input device 18 such as a mouse is used to display the display 1.
Designate the soldering land to be inspected on 7 (S
2).

When the board 25 is a double-sided board as shown in FIG. 5, it is judged whether or not the soldering lands on the front and back sides overlap each other (S3). When the soldering lands on the front and back sides overlap, a separation designation area centered on the designated soldering land to be inspected is set as shown in FIG. 5, and the size corresponding to the input layer of the separation neural network 6 is set. Cut out the image data of. The shape of each soldering land and its forming location (front or back) are known in advance. The arithmetic processing unit 4 to which the X-ray transmission image data and the designated data are input performs front-back separation processing using the separation neural network 6 when the front-back soldering lands overlap each other. If the substrate 25 is a single-sided mounting substrate or if the front and back soldering lands do not overlap, the process proceeds to step S5. As shown in FIG. 6, the separation neural network 6 has an input layer 1 layer and an intermediate layer 2
It has a four-layer structure consisting of one layer and one output layer, and has a pattern recognition function. In FIG. 6, each circle represents a neuron, and the line between the neurons represents a synaptic connection.
The number of neurons in the input layer is equal to the number of sampling points of the input signal, that is, the number of pixels, and the number of neurons in the output layer is equal to the number of items to be classified. In FIG. 6, a rectangle and a square are shown to be output in accordance with the two types of shapes shown in FIG.
Actually, the required soldering land shape is learned as teacher data. In the above configuration, the image data of the soldering lands required in advance in the output layer is given as a classification item, and the synaptic weight is changed from the initial value given by a random number or the like by the back propagation, and the corresponding image data is obtained. Train the output layer neurons so that they will respond correctly. If the image data of the specified area cut out after that is input, the output layer neuron of the shape approximated from the multiple shapes learned as the inspection target solder land from the image data partially deformed by the solder land on the opposite surface reacts. Therefore, an image of the soldering land on the front surface side where the overlap is separated is obtained (S4). In the example shown in FIG. 5, a rectangle on the front side and a square on the back side are output. Similarly, the soldering lands on the back surface side are recognized separately from the soldering lands on the front surface side.

Next, the center coordinates of the designated soldering land are obtained. An X-direction position detection neural network 7 and a Y-direction position detection neural network 8 are used to detect the center coordinates. The image data of the soldering land to be inspected is input to the input layer of each of the neural networks 7 and 8 in which the central coordinates of one shape are learned in advance as teacher data to obtain the central coordinates (S5, S).
6). As shown in FIG. 7, each of the position detection neural networks 7 and 8 has a four-layer structure of an input layer 1 layer, an intermediate layer 2 layer, and an output layer 1 layer, and the input is 16 × 16 image data. , Outputs are positions 0 to 15 indicating the center coordinates of the soldering land in the X or Y direction. The center of the soldering land is 0 in the teacher data as shown in FIG.
The image data is moved in the X direction or the Y direction so as to change one by one in the range from 15 to 15. By performing the processing using the neural network for separating the front and back sides of the soldering land and detecting the center coordinates, accurate processing is possible even from an image of the soldering land having an ambiguous shape in which the contour of the grayscale image is not clear. Become. Since the center coordinates of the soldering land are detected by the above processing (S7),
The following processing of S8 to S11 is the same as T5 in the first embodiment.
It is executed in the same manner as the steps from ~ T8.

In the method of specifying the inspection position, when the inspection target is the single-sided mounting board having the soldering lands formed on only one side, the processing procedure of steps S3 and S4 is not necessary. Therefore, the inspection position specifying device 1 can also be configured by omitting the separation neural network 6. Further, in the above-mentioned inspection position specifying device, when the desired inspection position of the soldering land can be detected by other means, the X direction center detection neural network 7 and the Y direction center detection neural network 8 are provided. It can be configured by changing to other means.

[0016]

As described above, according to the first method of the present invention, the soldering land is extracted by binarizing the X-ray transmission image of the unmounted board, and the soldering to be inspected is performed. By designating a land, the center coordinates of the land are determined, and the position of the component to be mounted on the designated soldering land is determined from the mounting position data of the component prepared in advance. The position of the soldering portion, that is, the inspection position is specified from the detected center coordinates of the soldering land and the position of the component. According to the second method of the present invention, the neural network pattern is used when the board is a double-sided board or when the outline of the soldering land of the X-ray transmission image of the unmounted board cannot be clearly obtained. By detecting the position of the soldering land from the X-ray transmission image on the unmounted board by the recognition function and designating the soldering land to be inspected, the position of the component attached to the specified soldering land is soldered. Calculated from the position of the attachment land. The inspection position is specified from the detected position of the soldering land and the position of the component. Therefore, in the method of the present invention, since the inspection position by the X-ray soldering inspection device is specified in advance by the unmounted board, the specified inspection position of the mounted board manufactured based on this unmounted board is the position of the component. Accurate inspection can be performed without being affected by misalignment or defective soldering.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment to which an inspection position specifying method according to a first embodiment of the present invention is applied.

FIG. 2 is a flowchart showing a procedure of an inspection position specifying method according to the first embodiment.

FIG. 3 is a block diagram showing the configuration of an embodiment to which the inspection position specifying method according to the second embodiment of the present invention is applied.

FIG. 4 is a flowchart showing a procedure of an inspection position specifying method according to a second embodiment.

FIG. 5 is a schematic diagram showing an example of an X-ray transmission image according to the second embodiment.

FIG. 6 is a schematic diagram showing a schematic configuration of a separation neural network according to a second embodiment.

FIG. 7 is a schematic diagram showing a schematic configuration of a position detection neural network according to a second embodiment.

FIG. 8 is a schematic diagram showing setting of center coordinate detection to be learned by the position detection neural network according to the second embodiment.

[Explanation of symbols]

 1, 20 ... Inspection position specifying device 2, 25 ... Board 2a, 25a ... Mounting board 3 ... Board image storage unit 4, 21 ... Arithmetic processing unit 5 ... Inspection position designation unit 6 ... Separation neural network 7 ... X direction inspection position detection Neural network 8 ... Y direction inspection position detection neural network 9 ... Inspection position data storage unit 10 ... X-ray soldering inspection device 22 ... Land image extraction unit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G06T 7/60 H05K 3/34 512 B 7128-4E 9061-5L G06F 15/70 465 A

Claims (3)

[Claims] 1. A soldering land of a substrate is irradiated with X-rays on a mounting substrate on which components are mounted by soldering, and the soldering is performed from an X-ray transmission amount distribution transmitted through a soldering portion on the soldering land. In a method of specifying an inspection position in an X-ray soldering inspection for determining quality of a part, a board in a state where no component is placed on the mounting board is placed at a predetermined position of an X-ray soldering inspection device that performs the soldering inspection. Set,
The substrate is irradiated with X-rays to capture an X-ray transmission image,
The line transmission image is binarized at a predetermined binarization level to create a binarized image in which soldering lands are extracted, the required soldering lands are designated in the binarized image, and the inspection target soldering is performed. A method for specifying an inspection position in an X-ray soldering inspection, which comprises obtaining a center coordinate of a land and then obtaining an attaching position and an attaching direction of a component to be soldered on the inspection target solder land. 2. An X-ray transmitted through a soldering portion on the soldering land by irradiating a mounting substrate on which a component is attached by soldering to a soldering land formed on one side or both sides of the substrate and transmitting through a soldering portion on the soldering land. In a method of specifying an inspection position in an X-ray soldering inspection for determining the quality of the soldered portion from a transmission amount distribution, a component is placed on the mounting board at a predetermined position of an X-ray soldering inspection device that performs the soldering inspection. A board in an unbroken state is set, the board is irradiated with X-rays to capture an X-ray transmission image, and an image area including a required soldering land is designated in the X-ray transmission image. The image data of the image area is input to an inspection position detection neural network in which the desired inspection position on the soldering land is learned in advance as teacher data, and the desired inspection position in the image area is input. A method for specifying an inspection position in an X-ray soldering inspection, which is characterized by detecting a position. 3. When the soldering lands on both sides of the board overlap in the image area, the image data of the image area is input to a separate neural network in which the shape of the soldering land is learned in advance as teacher data. The method for identifying an inspection position in an X-ray soldering inspection according to claim 2, wherein only the required soldering land is extracted.