KR102329518B1 - Linear multi image obtaining method for high-speed inspection of large area substrate using area scan camera - Google Patents

Abstract

The present invention relates to a technology which is capable of continuously photographing images of different colors in line units with respect to a large-area substrate by using an area scan camera and quickly obtaining inspection images of various colors by using the photographed images. The linear multi image obtaining method for high-speed inspection of a large-area substrate using an area scan camera in accordance with the present invention comprises: a first step in which a lighting means projects light sources of different colors to a scan section of a stage, wherein the plurality of color light sources are projected to different divided areas of the scan section; a second step of transferring a large-area substrate located on an upper surface of the stage to the scan section; a third step in which the area scan camera continuously photographs the large-area substrate transferred to the scan section of the stage to obtain a plurality of image frames in which the large-area substrate is made of different colors for each divided area position, wherein the image frames consist of photographed images at a time when the large-area substrate moves as much as the divided area of the scan section; and a fourth step in which an image analysis unit extracts and synthesizes the same color images with respect to different divided areas from the plurality of image frames acquired by the area scan camera such that different inspection images for each color can be generated for a single large-area substrate.

Description

Linear multi image obtaining method for high-speed inspection of large area substrate using area scan camera}

The present invention relates to a technology for continuously capturing images of different colors on a large-area substrate in line units using an area scan camera, and using them to quickly acquire inspection images of various colors.

With the rapid development of information and communication technologies, technologies for making electronic devices such as mobile phones, laptops, smart phones, and tablet PCs smaller, lighter and more functional are required. In order to realize the demands of these technologies, not only the miniaturization and high integration of electronic components mounted on electronic devices, but also the establishment of an overall infrastructure for high integration that can produce high-quality products such as mounting equipment, operation technology, inspection technology, and defect repair technology, and Mounting element technology became necessary.

In particular, the production of displays and semiconductors increases as the process time is shortened. Accordingly, process systems are efficiently designed using large-area substrates, and vision inspection is a method of inspecting large-area substrates. method is mainly used.

Vision inspection determines whether there is a defect in the product by analyzing the image taken by the camera of the chip moving at high speed. In general, vision inspection acquires and analyzes images within a short period of tens to hundreds of m/sec. If the vision inspection time is delayed, the overall part production time is delayed and productivity is reduced. Therefore, there is a demand for a vision inspection technology that accurately determines whether the appearance of a product is defective within a short time.

Such a vision inspection device generally includes a lighting device for illuminating light toward an inspection object, a camera for photographing the illuminated inspection object, and a manufacturing defect or good condition of the inspection object by comparing the screen photographed through the camera with a standard surface. It is provided with a discrimination means for discriminating.

In the case of a lighting device and a camera, it is usually disposed on the opposite side of the inspection object to irradiate light toward the inspection object and photograph the illuminated inspection object. It is determined whether the object to be inspected is manufactured in the correct state by comparing it with .

In this case, the vision inspection mainly acquires an inspection image of the inspection object using an area camera.

When an inspection image is acquired using such an area camera, inspection images for multiple colors of illumination can be secured because the image is taken while stopped on the inspection object, and inspection reliability of the inspection object is improved through inspection images of various colors There is an advantage to

However, since the width, length, and width of the photographing area of the area camera are determined, in the case of inspecting a large-area substrate over a certain area, photographing is performed while moving the position several times with respect to one large-area substrate. That is, it takes a lot of time according to the positional movement of the area camera in order to acquire the entire photographed image of the large-area substrate.

In addition, through an area camera, multiple images of a single large-area substrate are captured in a size that overlaps a certain portion, and in the vision inspection system, the overlapping portion is removed from the images captured by the area camera and combined through a stitching process. Complete the image for inspection. However, since errors may occur during such a stitching process, when an inspection is performed using an inspection image generated through this, there is a problem in that inspection accuracy is deteriorated.

Accordingly, there may be a method of acquiring an inspection image of an inspection object using a line scan camera.

However, the line scan camera has a disadvantage in that it cannot take inspection images of multiple colors because it shoots while passing by. That is, there is a problem in that the inspection object must be photographed three times in the same manner through the linescan camera in order to obtain an inspection image of three colors through the linescan camera.

1. Korea Patent No. 10-1731029 (Title of Invention: High-speed image measuring device) 2. Korea Patent No. 10-1566129 (Title of the invention: Line scan method moiré 3D shape measuring device and method)

Accordingly, the present invention was created in consideration of the above circumstances, by using an area scan camera to continuously shoot images of different colors on a large-area substrate in line units, and use them to quickly take inspection images of various colors. It has a technical purpose to provide a linear multi-image acquisition method for high-speed inspection of large-area substrates by using an area scan camera that allows to inspect whether defects on large-area substrates are more quickly and reliably by acquiring them.

According to one aspect of the present invention for achieving the above object, a light source is projected from a lighting means to a large-area substrate disposed on the upper surface of the stage, and an area scan camera disposed on the upper side of the stage is located in the scan section of the upper surface of the stage. In the linear multi-image acquisition method for high-speed inspection of large-area substrates by using an area scan camera that captures large-area substrates and acquires inspection images for determining whether the large-area substrates are defective, the scanning section of the stage in the lighting means The method of projecting light sources of different colors to each other, but the number of divided areas in the scan section is set to be larger than the number of color light sources in the lighting means, so that light sources of different colors are projected on different divided areas only to a certain divided area of the scan section. The first step, the second step of transferring the large-area substrate located on the upper surface of the stage to the scan section by the transfer means, the area scan camera continuously photographing the large-area substrate that transports the scan section of the stage to project the color light source A third step of acquiring a plurality of image frames composed of a captured image at the time point moved to the area, but setting only a divided area to which a color light source is projected to photograph only the corresponding portion; The same color images for different segmented regions are extracted from the image frame and synthesized to generate different inspection images for each color on one large-area substrate, but only the segmented regions to which the color light source is projected in multiple image frames are rearranged To provide a linear multi-image acquisition method for high-speed inspection of large-area substrates using an area scan camera, characterized in that it comprises a fourth step of generating inspection images for each color on one large-area substrate.

In addition, in the second step, the transfer means moves the large-area substrate disposed on the upper surface at a constant speed and transmits a pulse signal having a pulse width corresponding to the moving distance of the large-area substrate corresponding to the divided region of the scan section. generated and provided to the line scan camera, and in the third step, the area scan camera acquires an image frame in units of divided regions in synchronization with the moving distance of a large-area substrate based on a pulse signal. A linear multi-image acquisition method for high-speed inspection of large-area substrates is provided.

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In addition, in the fourth step, the image analysis unit sequentially rearranges a plurality of image frames, extracting each image frame in units of divided images and sequentially rearranging them in a line; Using an area scan camera, characterized in that it comprises the step of extracting divided images of the same color for different divided regions of the substrate to obtain a plurality of inspection images of different colors for the corresponding large-area substrate A linear multi-image acquisition method for high-speed inspection of area substrates is provided.

According to the present invention, it is possible to acquire inspection images of various colors through a single photographing process using an area scan camera, so that it is possible to more quickly inspect whether a large-area substrate is defective.

In addition, according to the present invention, inspection reliability for a large-area substrate can be improved by generating inspection images of various colors without going through a stitching process on an image captured by an area scan camera.

1 is a view showing a schematic configuration of a large-area board high-speed inspection system using an area scan camera to which the present invention is applied.
2 is a view for explaining a linear multi-image acquisition method for high-speed inspection of a large area substrate using an area scan camera according to the first embodiment of the present invention.
3 is a view for explaining the arrangement structure of the lighting means 100, the transport means 200, and the area scan camera 400 shown in FIG. 1 .
FIG. 4 is a diagram illustrating an image frame structure obtained by the area scan camera 400 shown in FIG. 3 and an image table in units of image frames.
FIG. 5 is a view showing a state in which the acquired images of FIG. 4 are rearranged in a continuous line form;
6 is a view for explaining a linear multi-image acquisition method for high-speed inspection of a large-area substrate using an area scan camera according to another embodiment of the present invention.

The configuration shown in the embodiments and drawings described in the present invention is only a preferred embodiment of the present invention, and does not express all the technical ideas of the present invention, so the scope of the present invention is the embodiment and drawings described in the text should not be construed as being limited by That is, since the embodiment may have various changes and may have various forms, it should be understood that the scope of the present invention includes equivalents capable of realizing the technical idea. In addition, since the object or effect presented in the present invention does not mean that a specific embodiment should include all of them or only such effects, it should not be understood that the scope of the present invention is limited thereby.

All terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. Terms defined in the dictionary should be interpreted as being consistent with the meaning of the context of the related art, and cannot be interpreted as having an ideal or excessively formal meaning not explicitly defined in the present invention.

1 is a diagram showing a schematic configuration of a large-area high-speed inspection system for a substrate using an area scan camera to which the present invention is applied.

Referring to FIG. 1 , a large-area board high-speed inspection system using an area scan camera to which the present invention is applied includes a lighting means 100 , a transfer means 200 , an imaging lens 300 and an area scan camera 400 and , and an image analysis 500 .

While the lighting means 100 is disposed on the transport means 200 , light sources of different colors are projected to different positions of the transport means 200 . In this case, each light source has a line structure having a predetermined length and a predetermined thickness. That is, a light source in the form of a line having a predetermined length and thickness is projected to the transfer means 200 .

1 illustrates a lighting means 100 provided with first to third light sources 110, 120, and 130 of three different colors. may be set differently depending on For example, the color "Red" is projected from the first light source 110 to the first divided area R1 of the transport unit 200 through one lighting means 100 and "Green" from the second light source 120 . The color may be projected to the second divided area R2 of the conveying means 200 , and the "Blue" color from the third light source 130 may be projected to the third divided area R3 of the conveying means 200 .

Here, as shown in FIG. 3 , the lighting means 100 may be configured in the form of a plurality of lighting means arranged at different positions and projecting different colors to the scan section of the transport means 200 .

In addition, the lighting means 100 may have a structure in which an angle and a wavelength band can be selected, and a line-shaped light source is transferred to the transport means 200 to prevent interference with a light source projected close using an optical means such as a lens. can be configured to project.

The transfer means 200 includes, for example, a conveyor for moving the large-area substrate 10 along the xy plane in a state where the large-area substrate 10 is disposed on the upper surface. At this time, the transfer means 200 may generate a pulse signal corresponding to the moving distance of the large-area substrate 10 by counting the signal generated from the encoder coupled to the conveyor at a preset period using a counter.

The imaging lens 300 is disposed under the area scan camera 400 to display divided images of different colors corresponding to each of the divided areas R1, R2, and R3 reflected by the surface of the large-area substrate 10. The area scan camera 400 forms an image.

The area scan camera 400 is disposed on the upper portion perpendicular to the transfer means 200 , and takes and scans the image projected on the large-area substrate 10 . In this case, the area scan camera 400 acquires an image frame in which portions corresponding to a plurality of divided regions have different colors in the large-area substrate 10 by one photographing. In addition, the area scan camera 400 may be scanned while floating using a grabber having a high CXP fps, or may be a flying camera.

That is, the area scan camera 400 acquires a plurality of image frames by continuously shooting at a shifted point in time for each division section of the large-area substrate 10 based on the pulse signal provided from the transfer means 200 . do.

The image analysis unit 500 extracts and synthesizes the same color images for different divided regions from a plurality of image frames acquired from the area scan camera 400, and thereby inspects images for each different color for one large-area substrate. It is configured to include an image analysis module 510 that generates

At this time, the image analysis module 510 compares a plurality of inspection images of different colors for one large-area substrate with a pre-registered standard large-area substrate image to determine whether the corresponding large-area substrate 10 is defective.

Next, a linear multi-image acquisition method for high-speed inspection of large-area substrates using the area scan camera according to the first embodiment of the present invention will be described with reference to FIGS. 2 to 5 .

First, the first to third lighting means 100-1, 100-2, and 100-3 project light sources of different colors to different divided areas of a preset scan section of the transport means 200 (ST100).

That is, as shown in FIG. 3 , the first lighting means 110-1 projects the first light source of the first color to the first divided area R1 of the scan section, and the second lighting means 110-2 projects the second light source of the second color to the second divided area R2 of the scan section, and the third lighting means 110-3 applies the third light source of the third color to the third divided area R3 of the scan section ) is projected.

At this time, the first to third lighting means 100-1, 100-2, 100-3 project the light source of the corresponding color to different divided areas of the scan section set in the transport means 200, and scan set in the transport means 200 The positions of the first to third lighting means 100 - 1 , 100 - 2 and 100 - 3 and the area scan camera 400 are appropriately set so that the section becomes a photographing area of the area scan camera 400 .

In the above state, the transfer means 200 operates the conveyor to move the large-area substrate 10 located on the upper surface of the conveyor at a constant speed (ST200).

At this time, the transfer means 200 generates a pulse signal in the form of a square wave in synchronization with the moving distance of the large-area substrate 10 as much as the divided area in the scan section, and transmits it to the area scan camera 400 . That is, a pulse signal having a pulse width corresponding to the moving distance of the large-area substrate 10 corresponding to the divided region size of the scan section set in the transfer means 200 and the conveyor moving speed is generated.

The area scan camera 400 photographs a scan section including the first to third divided regions R1, R2, and R3 according to a pulse signal provided from the transport means 200, and the scan section is different for each preset divided region. Image frames having color are continuously acquired (ST300). At this time, the area scan camera 400 continuously performs a photographing operation in units of divided areas of the scan section, and as shown in FIG. A first divided image I1 photographed in color, a second divided image I2 obtained by photographing the second divided area R2 in a second color, and a third divided area R3 photographed in a third color It consists of a third divided image I3.

That is, the area scan camera 400 initially acquires an image frame in which the first to third divided images I1, I2, and I3 are "x, x, A1" like the first frame of FIG. 4B. . Here, "x" represents a meaningless value, and "A1" is a state in which only area A of the large-area substrate 10 is moved to the scan section in FIG. It represents a divided image of the first color photographed by the light source 110 .

On the other hand, the conveyor 200 continuously performs a movement operation, and the area scan camera 400 continuously performs photographing for the scan section in synchronization with the movement distance corresponding to the division area unit of the large-area substrate 10 . The process of obtaining the image frame ( ST200 to ST300 ) is performed for the entire area of the large-area substrate 10 .

For example, as shown in FIG. 4B , the third to first divided images I3, I2, and I1 for the first to third divided regions R1, R2, and R3 are “x,x,A1” a first image frame, a second image frame corresponding to “x,A2,B1”, a third image frame corresponding to “A3,B2,C1”, ... These are obtained sequentially.

That is, in the present invention, since each image frame is composed of a plurality of divided images of different colors, images of the same color for different divided regions are located in different frames. For example, in the first image frame with respect to the entire area of the large-area substrate 10 of FIG. 3 , a divided image A1 of the first color for the first divided area R1 is obtained in the second frame, and the second divided area is obtained in the second frame. A divided image A2 of the first color for (R2) is obtained, and a divided image A3 of the first color for the third divided region R3 is obtained in the third image frame.

The area scan camera 400 provides the captured frame image to the image analysis unit 500 .

The image analysis unit 500 extracts the same color division images at different positions from a plurality of image frames corresponding to the scan section, and generates inspection images for each color of the large-area substrate 10 by using them (ST400). ).

That is, the image analysis unit 500 rearranges a plurality of image frames in a line, and extracts images of different positions for the same color of the measurement object 10 from the rearranged image frames to obtain the large-area substrate 10 . Create multiple inspection images of different colors for the whole. In this case, the image analysis unit 500 divides the image frame of the scan section into divided images in units of divided regions, and then sequentially rearranges each image frame in a line in units of divided images.

That is, the shape measuring unit 500 sequentially arranges a plurality of image frames in units of divided images in units of image frames, and N corresponding to different positions of the same color with respect to the large-area substrate 10 . Acquire a dog segmented image. In this case, “N” is a natural number corresponding to the number of divided regions in the scan section or the number of different colors of the lighting means 100 .

For example, the image analysis unit 500 rearranges the frame images shown in FIG. 4 in a form in which divided images are continuously and sequentially arranged as shown in FIG. 5 . In FIG. 5 , the first color inspection image of the large-area substrate 10 is generated by extracting three segmented images at N=3, that is, LINE3, LINE6, and LINE9, and combining the segmented images in the order of segmentation. In this case, the LINE3 image is the first color image A1 of the first divided region R1, LINE6 is the first color image B1 of the second divided region R2, and LINE7 is the third divided region ( The first color image C1 for R3). In addition, the second color inspection image consists of three segmented images at positions LINE4, LINE8, and LINE11.

That is, in the present invention, through the operation of continuously photographing the large-area substrate 10 transferred through the transfer means 200 in different colors, it can be used for defect inspection of the large-area substrate 100 through a single transfer process. Inspection images of various colors can be acquired at once.

The image analyzer 500 determines whether the large-area substrate 10 is defective by using the inspection images for each color of the large-area substrate 10 (ST500).

The image analysis unit 500 compares the inspection image for each color of the large-area substrate 10 with the previously registered standard image of the large-area substrate 10, and compares the inspection value corresponding to the similarity with each color inspection image. , and if the average value of the inspection values for each color inspection image is less than a preset inspection reference value, it may be determined as defective. In this case, the image analyzer 500 may determine whether or not there is a defect by assigning a weight to each color according to the type and height characteristics of the large-area substrate 10 . For example, when the height range of the large-area substrate 10 corresponds to the highest level, a maximum weight is given to the inspection value of the first color inspection image, and the large-area substrate 10 has a height range corresponding to an intermediate level. In this case, the maximum weight is given to the inspection value of the second color inspection image, and when the height range of the large-area substrate 10 corresponds to the lowest level, the maximum weight is given to the inspection value of the third color inspection image and the average value thereof Based on this, it can be judged whether it is defective or not.

On the other hand, in the above embodiment, as shown in Fig. 4 (A), the inspection image for each color is obtained by using an image frame in a state in which different color light sources are continuously projected onto the divided area at equal intervals from the lighting means 100. However, as shown in Fig. 6, the number of scan section division areas (R1 ~ R5) is set to be larger than the number of color light sources (3) of the lighting means 100, so that the first to third lighting means ( 100-1,100-2,100-3), by projecting light sources of different colors to the predetermined divided areas R1, R3, and R5 of the scan section, that is, each non-continuous divided area, the scan camera 400 is It is possible to obtain an image frame in which only the color images I3, I2, and I1 exist. That is, as shown in FIG. 6 , the color lights projected from the first to third lighting means 100-1, 100-2, and 100-3 may be set to be spaced apart from each other in units of divided areas.

In this case, the area scan camera 400 acquires a plurality of image frames corresponding to the captured images at the point in time when the color light source is moved to the divided area on which the color light source is projected onto the large-area substrate 10 . In addition, the area scan camera 400 may be configured to set only a divided area to which a color light source is projected to photograph only the corresponding portion.

In addition, the image analysis unit 500 rearranges only the divided area to which the color light source is projected in the image frame including the divided area to which the color light source is projected, obtained through the area scan camera 400, as shown in FIG. 5 to form one large area. Inspection images for each color of the substrate can be generated.

In addition, the image analysis unit 500 extracts color images from a plurality of image frames obtained from the area scan camera 400 in different divided regions, and superimposes them on the standard image of the large-area substrate registered in advance. , it is also possible to generate different inspection images for each color for one large-area substrate.

100, 100-1,100-2,100-3: means of lighting;
110, 120, 130: light source, 200: transport means,
300: focusing lens, 400: area scan camera;
500: image analysis unit, 510: image analysis module. One

Claims (4)

The lighting means projects a light source to a large-area substrate placed on the upper surface of the stage, and an area scan camera placed on the upper side of the stage takes pictures of the large-area substrate located in the scan section of the upper surface of the stage to determine whether the large-area substrate is defective. In the linear multi-image acquisition method for high-speed inspection of large-area substrates using an area scan camera that acquires inspection images for judgment,
Light sources of different colors are projected from the lighting means to the scan section of the stage, but the number of divided areas in the scan section is set to be larger than the number of color light sources in the lighting means, so that light sources of different colors are applied to each other only in a certain divided area of the scan section. A first step of projecting to another divided area;
A second step of transferring the large-area substrate located on the upper surface of the stage in the transfer means to the scan section;
The area scan camera continuously shoots a large-area substrate that transports the scan section of the stage to acquire a number of image frames consisting of the captured images at the point in time when the color light source is moved to the divided area to be projected, but only the divided area to which the color light source is projected A third step of setting and shooting only the corresponding part; and
The image analyzer extracts the same color images for different segmented regions from multiple image frames acquired from the area scan camera and synthesizes them to generate different inspection images for each color on one large-area substrate, but multiple images High-speed large-area substrate using an area scan camera, characterized in that it comprises a fourth step of generating inspection images for each color on one large-area substrate by rearranging only the divided regions on which the corresponding color light source is projected in the frame Linear multi-image acquisition method for inspection.
delete According to claim 1,
In the second step, the transfer means moves the large-area substrate disposed on the upper surface at a constant speed and generates a pulse signal having a pulse width corresponding to the moving distance of the large-area substrate corresponding to the divided region of the scan section. provided by the area scan camera,
In the third step, the area scan camera is a linear for high-speed inspection of large-area substrates using an area-scan camera, characterized in that it acquires an image frame in units of divided regions in synchronization with the moving distance of a large-area substrate based on a pulse signal. How to acquire multiple images.
According to claim 1,
In the fourth step, the image analysis unit sequentially rearranges a plurality of image frames, extracting each image frame in units of divided images and sequentially rearranging them in a line;
Extracting divided images of the same color for different divided regions of a large-area substrate from the divided images that are sequentially rearranged in a line to obtain a plurality of inspection images of different colors for the large-area substrate Linear multi-image acquisition method for high-speed inspection of large-area boards using an area scan camera, characterized in that.

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