JP2000088762A - Visual inspection apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform an inspection with good efficiency by means of a small memory capacity by providing a technique by which only image data around a region to be inspected is extracted. SOLUTION: This visual inspection apparatus which is constituted is provided with a position-data fetch part 1 in which a relative position with reference to an object to be inspected is detected as position data. It is provided with an image fetch part 2 which images the visual image of the object to be inspected. It is provided with an image-fetch control part 3 which controls an image fetch operation on te basis of inspection position data indicating a region as the object to be inspected. It is provided with a movement mechanism part 4 on which the object to be inspected is placed and which conveys the object, to be inspected, at a prescribed movement speed. It is provided with a position-data storage part 5 which stores position data corresponding to a desired region. It is provided with an image-data storage part 6 which stores image data fetched on the basis of the position data. It is provided with an inspection processing part 7 which extracts the image data on the object to be inspected and in which whether the object to inspected is good or not is evaluated and judged by applying a knwon image analyzing technique.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a visual inspection apparatus for determining the quality of a two-dimensional pattern formed on a printed wiring board or the like.

[0002]

2. Description of the Related Art In recent years, miniaturization of flexible printed wiring boards has been progressing with the development of technology for miniaturizing electronic components. This flexible printed wiring board has various shapes depending on the application, and in the manufacturing process, so-called multi-paneling, in which a plurality of products are formed on one sheet-like substrate in order to manufacture many products at the same time. Is often performed.

[0003] When multiple products are formed, the dimensions and shapes of individual products are various. Therefore, in an inspection process such as a dimension measurement inspection or an appearance inspection, the actual area to be inspected is small. The size of the inspection target differs depending on the inspection position, or the required measurement accuracy differs depending on the region. An example of a conventional flexible printed wiring board appearance inspection apparatus that performs such an inspection will be described with reference to FIG. FIG. 6 is a schematic configuration diagram of a conventional visual inspection device.

As shown in FIG. 6, a visual inspection device 20 includes a line CCD camera 21 and an image memory 22 for storing image data captured by the line CCD camera 21.
And an inspection processing unit 23 that reads out image data from the image memory 22 and determines whether the pattern is good or bad by using a well-known image analysis technique. In the appearance inspection apparatus 20 having such a configuration, the line CC is sequentially moved while the multiple substrate 25 mounted on the transfer stage 24 is moved in the direction of the arrow A in the drawing (hereinafter, referred to as a capturing direction).
The pattern image of the product on the multiple substrate 25 is captured by the D camera 21 and stored in the image memory 22. The inspection processing unit 23 takes out the image data stored in the image memory 22, performs a pattern size measurement inspection and an appearance inspection by using a comparison process with the design data and an image matching technique, and obtains a result of the pass / fail judgment. Output.

Here, for a line CCD camera,
Although the mechanism for moving the substrate side by the transfer stage has been described, there is also a method of moving the line CCD camera with respect to the substrate. As described above, by using the line CCD camera and the transport system, while extracting image data (for example, 4096 pixels) having a predetermined width in the scanning direction (the direction perpendicular to the capturing direction A), the image memory in the capturing direction A is used. There is an advantage that image data can be extracted by an amount corresponding to the capacity of, and a wide imaging area can be obtained.

In addition, since the resolution of an image in the capturing direction is determined according to the speed at which the camera or the substrate to be inspected is moved, the resolution can be arbitrarily set by increasing the moving speed in a portion where high resolution is not required. In addition, the time required for imaging can be reduced.

[0007]

In such a conventional visual inspection apparatus, as shown in FIG. 7 (a), a line CCD of a multi-panel substrate 30 on which various types of products 31a to 31c are arranged is used. An image R obtained by area division with the scanning width Ws of the camera 21 is captured. FIG. 7B shows a partial area Ra of the image R in detail. A predetermined functional area and a wiring pattern are formed in the area Ra. Generally, in the appearance inspection process, only a small area of a product, for example, FIG.
In many cases, only the wiring dimension width in the frame B in (b) is to be inspected. In such a case, only a small amount of data required in the image data stored in the image memory 22, for example, 10 Although it is less than one-half, most of the data is not used for inspection, but a large amount of memory capacity is required as image data, which causes a problem that the scale of peripheral circuits increases. Was.

An object of the present invention is to solve the above-mentioned problem and propose a technique for extracting only image data around an inspection target area, thereby providing an appearance inspection apparatus capable of performing efficient inspection with a small memory capacity. To provide.

[0009]

According to one aspect of the present invention, there is provided an image reading unit which captures an external appearance image of an inspection object and takes in the image as a series of image information. A moving mechanism unit that relatively changes a positional relationship with the image reading unit; a position information reading unit that detects position information of the image reading unit with respect to the inspection target in the moving mechanism unit; An image capturing control unit that controls capturing of the image information based on inspection position information indicating the position information corresponding to the area, and a position information storage unit that stores the position information corresponding to the desired area. An image information storage unit that stores the image information in association with the position information, and extracts and analyzes only the image information of the desired area based on the position information. And having a checking unit for evaluating the test object.

According to a second aspect of the present invention, in the appearance inspection apparatus of the first aspect, the image capturing control unit captures only the image information corresponding to the desired area and stores the image information in the image information storage unit. It is stored. According to a third aspect of the present invention, in the visual inspection device according to the first or second aspect, the moving mechanism unit is configured to position the inspection object and the image reading unit in the desired area and outside the area. Is configured to be able to change the speed at which is changed.

[0011] The invention described in claim 4 is based on claim 1,
4. The visual inspection device according to item 2 or 3, wherein the inspection position information is set based on the design information of the inspection target. According to such an appearance inspection device, the image capture control unit stores the image information of the desired area in the image information storage unit in association with the position information of the desired area, and the inspection processing unit stores the image information of the area corresponding to the position information. Only the image information of the inspection target can be extracted and analyzed, so that the image information of the inspection target area can be easily extracted even when the arrangement of the pattern to be inspected is not uniform, thereby improving the efficiency of the inspection processing. Can be planned.

Also, since only the image information of the inspection target area can be stored in the image information storage section, the memory capacity can be reduced and the scale of the peripheral circuit can be reduced. In addition, even when the inspection target exists on the same product and the resolution required for the inspection processing is different, by changing the reading speed based on the position information,
Since the image information can be read by changing the resolution, only the image information to be inspected can be efficiently read and used for the inspection.

Further, by using design information used in a pattern manufacturing process such as CAD as position information, a region to be inspected is easily specified, and only image information of a corresponding region is taken in. Since the data can be captured at a desired resolution, an efficient inspection process can be realized.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The basic structure of a visual inspection apparatus according to the present invention will be described with reference to FIG. As shown in FIG. 1, the visual inspection apparatus according to the present embodiment includes a position data capturing unit 1 that configures a position information reading unit, an image capturing unit 2 that configures an image reading unit, an image capturing control unit 3, It has a moving mechanism section 4, a position data storage section 5 constituting a position information storage section, an image data storage section 6 constituting an image information storage section, and an inspection processing section 7.

The image capturing unit 2 is, for example, a line CCD.
And has a function of capturing an external appearance image of an inspection target such as a printed wiring board and taking in a series of image data. For example, the moving mechanism unit 4 places the inspection target on the transport stage that transports the inspection target at a predetermined moving speed, or the line C with respect to the inspection target fixed on the stage.
A linear motion mechanism for moving the CD at a predetermined speed. In short, any device can be used as long as it can move the line CCD at a predetermined speed relative to the inspection target and capture the image of the inspection target in the moving direction (capture direction).

The position data take-in section 1 comprises, for example, a detector (scaler) for detecting the amount of movement of the transfer stage, and has a function of detecting the relative position of the line CCD with respect to the inspection target as position data. The image capturing control unit 3 controls to capture only the image data of the corresponding area based on inspection position data indicating an area to be inspected (position data indicating an inspection area set based on design information such as CAD data). Alternatively, control is performed to capture only the image data of the corresponding area at a desired resolution.

The position data storage unit 5 comprises, for example, a position data memory, and stores position data corresponding to a desired area (an area in which image data is fetched). The image data storage unit 6 includes, for example, an image data memory, and stores the image data acquired based on the position data in association with each other. The inspection processing unit 7 extracts the image data of the inspection target stored based on the position data, and evaluates / determines the quality of the inspection target by applying a known image analysis technique.

The concept of the inspection process in the visual inspection apparatus having such a configuration will be described with reference to FIG. First,
In the inspection processing unit 7, an area to be inspected is determined based on the design information (CAD data), and position data corresponding to the area is calculated from the design information (S1). The calculated position data is set as inspection position data in the image capturing control unit 3 (S2).

Next, while moving the multiple substrate on the stage by the moving mechanism section 4, the position data is taken in by the position data take-in section 1 and stored in the position data storage section 5; Referring to the data, the image data is controlled to be fetched from the image fetch unit 2 and stored in the image data storage unit 6 (S3).

Here, the stored position data and image data are, for example, the image data is continuously stored in the image data storage unit 6, and the position data storage unit 5 and the head of the corresponding one-line image data together with the position data. The address is set, and the image data is associated with the position data (S4). Next, based on the inspection position data by the inspection processing unit 7,
Referring to the position data stored in the position data storage unit 5,
The necessary image data is extracted from the image data storage unit 6,
A dimension measurement and a pass / fail judgment inspection are performed (S5).

Since the image data and the position data are stored in association with each other by such inspection processing, the image data of the inspection target area can be easily extracted, and the inspection time can be reduced. Further, since only the inspection target area is stored, the memory usage can be reduced, and the scale of the peripheral circuit can be reduced.

[0022]

Next, an embodiment of a visual inspection apparatus having the above-described basic configuration will be described with reference to FIG. FIG.
As shown in FIG. 1, the appearance inspection apparatus according to the present embodiment includes a position data input circuit 11 constituting a position data acquisition unit, a line CCD camera 17 constituting an image acquisition unit, and a capture instruction circuit 16 constituting an image acquisition control unit. An image input circuit 12, a mechanism system 18 constituting a moving mechanism section, a position data memory circuit 13 constituting a position data storage section,
It has an image memory circuit 14 constituting an image data storage unit and a processing CPU 15 constituting an inspection processing unit.

Here, the line CCD camera 17 is fixed, the object to be inspected is placed on the mechanism system 18, and the mechanism system 18 is moved, so that the positional relationship between the line CCD camera 17 and the object to be inspected is relatively changed. In addition, CAD data is used as information for setting an inspection target area. Next, an example of a pattern of a multi-panel substrate to be subjected to an appearance inspection will be described with reference to FIG. FIG. 4 is an enlarged view of a pattern formed on the multiple substrate.

As shown in FIG. 4, a line C is formed on the hole 32 and the wirings 33a and 33b formed on the multiple substrate.
The image is captured by scanning the CD camera 17 in the X direction and the line CCD camera 17 is moved in the Y direction. Can be captured.

Here, for example, the hole 32 is used as a dimension inspection.
When inspecting the hole diameter, the width W1 of the wiring 33a, and the interval W2 between the wirings 33a and 33b, the inspection can be performed with the resolution in the X direction (resolution of the line CCD camera). Only the image data at the position of the line LL 'in the figure need be captured, and it is not necessary to capture the image data of the other portions. Therefore, even if the image data of a predetermined area on the multi-plane substrate is captured, The image data used in the actual inspection is very small, and most of the other data is not used even if it is captured.

A specific example in which the appearance inspection apparatus of this embodiment shown in FIG. 3 is applied to the appearance inspection having such features will be described with reference to FIG. Here, a case in which only image data to be inspected is captured will be described. FIG. 5 is a diagram viewed from a surface (inspection surface) for capturing an image of the product 31 formed on the multiple substrate 30.

First, the processing CPU 15 sets the multiple board 30
An area to be inspected is determined based on the design information, and position data (for example, a distance from an image capturing start point (point 0 in the drawing)) corresponding to the area is calculated from the design information. The calculated inspection position data (for example, 50 to 15
0, 200 to 300,...
Is set to

Next, as shown in FIG. 5, the line CCD camera 17 having the scanning width Ws is set at the position of 0,
The mechanism system 18 for moving the stage on which the multi-chip substrate 30 is mounted takes the multi-chip substrate 30 in the direction of taking in (Y direction).
And the line CCD camera 17 can capture an image in the capturing direction on the multiple substrate 30.

At the same time, the position data is sent from the mechanism system 18 to the position data input circuit 11,
Sends the position data to the instruction circuit 16. The capture instruction circuit 16 determines whether or not the position of the area to be inspected is designated by the inspection position data from the processing CPU 15 based on the position data from the position data input circuit 11, and the position of the image until the position of the inspection object is reached. Since the capture is not performed, the image input circuit 12 is instructed to stop the capture.

Next, the stage is moved at a constant speed in the direction opposite to the Y direction by the mechanism system 18, and the position data is sequentially sent from the mechanism system 18 to the position data input circuit 11.
The fetch instruction circuit 16 monitors whether the position data from the position data input circuit 11 is the position of a region to be inspected specified by the inspection position data from the processing CPU 15.

When the position data reaches the position 50, which is the start point of the area to be inspected, the fetch instruction circuit 16 sends the image data to the image input circuit 12 and the image memory circuit 1
4 is stored. The line CCD camera 17 scans the width Ws in the scanning direction (X direction) and sends the image data to the image input circuit 12. At the same time, the position data is stored together with the start address of the storage position of the image data corresponding to the position data memory circuit 13, and the stored image data is associated with the position data.

Subsequently, when the position data and the image data are fetched at a resolution of, for example, once every 10 μm, and come to the position 150 which is the end point of the area to be inspected, the fetch instruction circuit 16 sets the image input circuit 12 Is instructed to stop capturing image data. Thereafter, the image data is not captured until the position 200 of the start point of the next area to be inspected is reached, and the capturing instruction circuit 16 monitors the position data.

When the position data arrives at 200, the fetch instruction circuit 16 instructs the image input circuit 12 to store the image data in the image memory circuit 14, and the image data and the position data are stored. As described above,
Only the image data of the area to be inspected on the multiple substrate is taken in, stored in the image memory circuit 14, and the corresponding position data is stored in the position data memory circuit 13.

Next, another specific example will be described with reference to FIGS.
This will be described with reference to FIG. Here, a case in which an image is captured while changing the resolution in the capturing direction will be described. First, the processing CPU 15 determines an area to be inspected based on the design information of the multiple substrate 30, and determines position data (for example, an image capturing start point (point 0 in the figure) corresponding to the area).
Is calculated from the design information. The calculated inspection position data (for example, 50 to 150, 200 to 300,
..) Are set in the loading instruction circuit 16 and the mechanism system 18.

Next, as shown in FIG. 5, the line CCD camera 17 having the scanning width Ws is set to the position of 0,
The mechanism system 18 for moving the stage on which the multi-chip substrate 30 is mounted takes the multi-chip substrate 30 in the direction of taking in (Y direction).
And the line CCD camera 17 can capture an image in the capturing direction on the multiple substrate 30.

At this time, the processing system 1
Since the position data of the area to be inspected is designated as the inspection position data from 5, the moving speed of the stage in the capturing direction is moved at a speed of capturing an image at a resolution of once every 20 μm. It instructs the image input circuit 12 to store the image in the image memory circuit 14.

The line CCD camera 17 sequentially scans the width Ws in the scanning direction (X direction) and outputs the image to the image input circuit 1.
Send to 2. At the same time, the position data is stored together with the start address of the storage position of the image data corresponding to the position data memory circuit 13, and the stored image is associated with the position data. Then, when the position data reaches the position of the start point 50 of the region to be inspected, the mechanism system 18 sets the moving speed of the stage in the capturing direction to the speed of capturing an image at a resolution of once every 10 μm (1/2). At the end point 150 of the area whose position data is to be inspected, the moving speed of the stage in the capturing direction is again set to 20 μm.
Change the speed to capture an image at a resolution of once per m.

During this time, image capture by the line CCD camera 17, storage of the image by the image input circuit 12, and storage of the position data and the start address of the image data by the position data input circuit 11 are continued. As described above, high-resolution image data is obtained only in the area to be inspected on the multi-chip substrate, and low-resolution (half resolution) is used in other areas.
Are stored in the image memory circuit 14.

In the specific example described above, the inspection position data for changing the resolution is sent to the mechanism system 18 and the mechanism system 18 autonomously controls the speed. However, the present invention is not limited to this. Instead, for example, the capturing instruction circuit 16 may control the mechanism system 18 to change the speed. The image data stored in the image memory circuit 14 as in each of the specific examples described above is processed by the processing CPU 1.
5 refers to the contents of the position data memory circuit 13,
A required image in the image memory circuit 14 is read,
Further, the resolution in the image capturing direction is specified by the increment of each position data in the position data memory circuit 13 (10 μm and 20 μm in the above specific example), and inspection and dimension measurement are performed.

In each of the specific examples described above, the case where the distance from the capturing start position is used as the position data is shown, but the present invention is not limited to this. In short, it suffices if the position on the multiple substrate can be specified, the resolution can be specified, and the inspection and the dimension measurement can be performed.

[0041]

As described above, according to the appearance inspection apparatus of the present invention, the image capturing control section stores the image information of the desired area in the image information storage section in association with the position information of the desired area, Since the inspection processing unit can extract and analyze only the image information of the area corresponding to the position information, even when the arrangement of the pattern to be inspected is not uniform,
Image information of the inspection target area can be easily extracted,
Inspection processing can be made more efficient.

Further, since only the image information of the inspection target area can be stored in the image information storage section, the memory capacity can be reduced and the scale of the peripheral circuit can be reduced. In addition, even when the inspection target exists on the same product and the resolution required for the inspection processing is different, by changing the reading speed based on the position information,
Since the image information can be read by changing the resolution, only the image information to be inspected can be efficiently read and used for the inspection.

Further, by using design information used in a pattern manufacturing process such as CAD as position information, a region to be inspected is easily specified, and only image information of the corresponding region is taken in, or only the corresponding region is read. Since the data can be captured at a desired resolution, an efficient inspection process can be realized.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram of a visual inspection device according to the present invention.

FIG. 2 is a conceptual diagram of a process performed by the visual inspection device according to the present invention.

FIG. 3 is a view showing one embodiment of a visual inspection device according to the present invention.

FIG. 4 is a diagram showing an example of a pattern of a multi-panel substrate.

FIG. 5 is a diagram of an inspection surface of a multi-surface board.

FIG. 6 is a schematic configuration diagram of a conventional visual inspection device.

FIG. 7 is an inspection surface view of a multi-surface substrate and an enlarged view thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Position data acquisition part 2 Image acquisition part 3 Image acquisition control part 4 Moving mechanism part 5 Position data storage part 6 Image data storage part 7 Inspection processing part 11 Position data input circuit 12 Image input circuit 13 Position data memory circuit 14 Image memory circuit Reference Signs List 15 processing CPU 16 capture instruction circuit 17 line CCD camera 18 mechanism system 20 visual inspection device 21 line CCD camera 22 image memory 23 inspection processing unit 24 transfer stage 25 multi-surface substrate 30 multi-surface substrate 31a to 31c products 32 holes 33a, 33b wiring

Claims (4)

[Claims] An image reading unit that captures an appearance image of an inspection target and captures the image as a series of image information; a moving mechanism unit that relatively changes a positional relationship between the inspection target and the image reading unit; A mechanism unit configured to detect position information of the image reading unit with respect to the inspection target; and a position information reading unit configured to detect the position information corresponding to a desired area of the inspection target. An image capture control unit that controls capture of the image, a position information storage unit that stores the position information corresponding to the desired area, an image information storage unit that stores the image information in association with the position information, An inspection processing unit that extracts and analyzes only the image information of the desired area based on the position information and evaluates the inspection target. Visual inspection apparatus. 2. An appearance inspection apparatus according to claim 1, wherein said image capture control section captures only said image information corresponding to said desired area and stores said image information in said image information storage section. 3. The apparatus according to claim 1, wherein the moving mechanism is configured to be able to change a speed of changing a positional relationship between the inspection object and the image reading unit inside and outside the desired area. An appearance inspection apparatus according to claim 1. 4. The inspection position information is set based on design information of the inspection object.
The visual inspection device according to 2 or 3.