KR101198406B1 - Pattern inspection device - Google Patents

Abstract

A method and apparatus for inspecting a pattern are provided. An apparatus for inspecting a pattern formed on a light related plate element according to an aspect of the present invention includes a first light source for illuminating reflected light on an upper surface of the light related plate element, a first camera for photographing the upper surface illuminated by the reflected light, A second light source for illuminating transmitted light on a lower surface of the light-related plate element, a second camera for photographing an upper surface of the light-related plate element through which the transmitted light is transmitted, and the pattern photographed by the first camera and the second camera The pattern checking unit may include a pattern inspecting unit detecting a portion having a value higher than a predetermined reference luminance to determine whether the pattern is defective.
In addition, the present invention provides an apparatus for correcting in real time so that there is no problem in inspection when a focal length error of the camera with respect to the light-related plate element occurs due to the deflection or flatness unevenness due to the load of the light-related plate element. In addition, by providing a device capable of simultaneously detecting various defects, that is, short and open defects, with respect to the pattern of the light-related plate element, it is possible to overcome the limitations of the prior art that a plurality of inspection systems must be used.

Description

Pattern inspection device {PATTERN INSPECTION DEVICE}

The present invention relates to a pattern inspection apparatus, and more particularly, to an apparatus for inspecting a pattern formed on the light-related plate element.

In general, flat panels such as LCDs and PDPs are configured by stacking or including light-related plate elements such as glass substrates or optical patterns, and attaching dust, cracks, stamps, scratches, and edge film to the light-related plate elements. As described above, various defects such as short and open of the pattern of the light-related plate element appear.

In order to determine the pattern defects of such light-related plate elements, inspection and discrimination are usually performed by the naked eye, and thus there is a problem that the accuracy of inspection decreases, which will greatly affect the productivity of the flat panel.

Therefore, in the conventional optical automatic inspection system (hereinafter referred to as "inspection system"), defects are inspected for patterns of optical-related plate elements using a camera, an image sensor and a lighting device. However, There was a limitation in that two or more other pattern defects could not be detected continuously.

For example, in the prior art, an inspection system for inspecting a short, a shot, a scratch, an edge film jamming, and an inspection system for an open inspection were separately provided.

This is because one inspection method (algorithm) does not detect two or more different pattern defects. Thus, in order to perform both short and crack, stamping, scratch and open inspection, Inspections for shorts, imprints, scratches, etc. were first performed, and then the flat panel was separated and discharged from the inspection system, followed by an open inspection in an inspection system for open inspection.

Therefore, in performing the pattern inspection of a plurality of light-related plate elements, the conventional inspection system has the trouble of performing the inspection again after separating and discharging the flat panel, and thus the cost and inspection time for the two inspection systems. This growing problem is still unsolved.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an apparatus capable of simultaneously detecting various defects of a light-related plate element, that is, defects such as short and open, in order to solve the problems of the above-

In addition, the present invention provides an apparatus for correcting in real time so that there is no problem in inspection when a focal length error of the camera with respect to the light-related plate element occurs due to the deflection or flatness unevenness due to the load of the light-related plate element. do.

The present invention also provides a method of arranging components to shorten the defect inspection time for the pattern of light related plate elements.

The objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned can be clearly understood from the following description.

According to the present invention for achieving the above object, an apparatus for inspecting a pattern formed on a light-related plate element is a first light source for illuminating the reflected light on the upper surface of the light-related plate element, photographing the upper surface illuminated by the reflected light A first camera, a second light source for illuminating transmitted light on a lower surface of the light-related plate element, a second camera for photographing an upper surface of the light-related plate element through which the transmitted light is transmitted, and by the first camera and the second camera And a pattern inspection unit for detecting a portion having a value higher than a predetermined reference luminance in the photographed pattern to determine whether the pattern is defective or not.

The apparatus also includes a focal length automatic adjustment unit for correcting a focal length error of the camera caused by a load of the light-related plate element or a flatness unevenness. BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG.

The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. It is provided to fully inform the owner of the scope of the invention.

According to one of the problem solving means of the pattern inspection apparatus of the present invention described above, two or more different defects can be continuously inspected with respect to the pattern of the light-related plate element.

Further, by arranging a plurality of cameras for inspecting defects for the pattern of the optical-related plate elements continuously in the scanning direction which is the advancing direction of the flat panel including the optical-related plate elements, the inspection time is shortened, It can also contribute to reduced time.

1 is a diagram illustrating a system for inspecting a pattern defect of a light related plate element according to an embodiment of the present invention.
2 is a block diagram illustrating an apparatus for inspecting a pattern defect of a light related plate element according to an embodiment of the present invention.
3A is a diagram illustrating a method of illuminating reflected light on an upper surface of a light-related plate element of the first light source 110 according to an embodiment of the present invention.
3B is a diagram illustrating a method of illuminating transmitted light on a bottom surface of a light-related plate element of the second light source 130 according to an embodiment of the present invention.
4 is a view illustrating a pattern defect detection method of a light-related plate element of the pattern inspection unit 150 according to an embodiment of the present invention.
5A and 5B are actual images of defects detected by the pattern inspecting unit 150 according to an embodiment of the present invention.
6 is a flowchart illustrating a process of inspecting a pattern defect of a light-related plate element according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention.

The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In order to clearly explain the present invention in the drawings, parts not related to the description are omitted, and similar parts are denoted by similar reference numerals throughout the specification.

For reference, in the entire specification, when a part is "connected" to another part, it is not only "directly connected" but also "electrically connected" with another element in between. Also includes.

Also, when an element is referred to as "comprising ", it means that it can include other elements as well, without departing from the other elements unless specifically stated otherwise.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

1 is a diagram illustrating a system for inspecting a pattern defect of a light related plate element according to an embodiment of the present invention.

The system for inspecting a pattern defect of a light related plate element according to an embodiment of the present invention includes a first light source 110, a first camera 120, a second light source 130, and a second camera 140. .

Briefly describing each component, the flat panel 200 is moved in a constant scan direction with respect to the first camera 120 and the second camera 140 by a conveyor (not shown) or a robot (not shown).

When the flat panel 200 starts to move, the first light source 110 illuminates the reflected light on the upper surface of the light associated plate element, and the first camera 120 is illuminated by the reflected light by the first light source 110. Photograph the upper surface of the light-related plate element.

In addition, the second light source 130 illuminates the transmitted light on the lower surface of the light-related plate element when the flat panel 200 moves in the scan direction by a conveyor (not shown) or a robot (not shown) to enter a predetermined area. do.

Thereafter, the second camera 140 photographs an upper surface of the light related plate element through which the transmitted light of the second light source 130 is transmitted.

Here, the "light-related plate element" includes a glass substrate and an optical pattern plate included in the flat panel 200, such as LCD, PDP.

For reference, as described above, illumination of the first light source 110 and photographing of the first camera 120 are preceded, and then illumination of the second light source 130 and photographing of the second camera 140 are performed. It is not required to be performed, and illumination of the second light source 130 and photographing of the second camera 140 may be preceded.

The system shown in FIG. 1 checks the focal distance of each camera 120, 140 with respect to the flat panel 200 through the focal length automatic adjustment unit 160 before capturing each camera 120, 140 If a predetermined focal length and error occurs, the cameras 120 and 140 may be adjusted up and down to maintain the predetermined focal length.

1 detects a portion having a value higher than a predetermined reference luminance in a pattern of an image photographed by the first camera 120 or the second camera 140, It is possible to determine whether there is a defect.

2 is a block diagram illustrating an apparatus for inspecting pattern defects of an optical-related plate element according to an embodiment of the present invention.

An apparatus for inspecting a pattern defect of a light related plate element according to an exemplary embodiment of the present invention may include a first light source 110, a first camera 120, a second light source 130, a second camera 140, and a pattern inspection unit. 150 and a focal length auto adjuster 160, the apparatus shown in FIG. 2 may be included in the system shown in FIG.

Referring to each component, the first light source 110 is a flat panel (hereinafter referred to as a 'flat panel'), such as LCD, PDP, including a light-related plate element on a conveyor (not shown) or a robot (not shown) In the scan direction, the reflected light is illuminated on the upper surface of the light-related plate element (hereinafter, referred to as a "light-related plate element") of the flat panel 200.

The reflection light illumination method of the first light source 110 will be described later with reference to FIG.

Meanwhile, the first camera 120 photographs an upper surface of the light related plate element illuminated by the reflected light by the first light source 110.

Here, the first camera may be a line scan camera, and the flat panel 200 moves in a constant scan direction with respect to the first camera 120.

The first camera 120 photographs the pattern of the light-related plate elements existing in the photographing area and has a linear photographing area perpendicular to the scan direction which is the moving direction of the flat panel 200, To send).

As will be described later, the pattern inspection unit 150 is a short (short), edge (edge) film cracking, cracking and scratches with respect to the pattern of the light-related plate element through the image taken by the first camera 120 It is possible to determine whether or not such a defect.

For reference, the resolution of the image photographed by the first camera 120 may be determined by the moving speed of the flat panel 200 and the exposure time of the first camera 120.

The first camera 120 may be spaced apart from the upper surface of the flat panel 200 by a predetermined distance so that a certain distance between the flat panel 200 and the first camera 120 is a flat distance It may be a predetermined focal length for capturing the panel 200.

In addition, the first camera 120 may be continuously disposed in a scan direction which is a moving direction between the second camera 140 and the flat panel 200.

On the other hand, the second light source 130 illuminates the transmitted light on the lower surface of the light-related plate element when the flat panel 200 proceeds.

The transmission light illumination method of the second light source 130 will be described later with reference to FIG. 3B.

When illuminating the transmitted light on the lower surface of the flat panel 200, since the 'light' appearing as a dark portion in the pattern of the light-related plate element and the bright portion between the 'lead' and the 'lead' appear clearly distinguished, It is possible to efficiently detect openness of a defect with respect to a pattern of a plate element.

Meanwhile, the second camera 140 photographs an upper surface of the light related plate element through which the transmitted light of the second light source 130 is transmitted.

The second camera 140 may also be a line scan camera and may be arranged in parallel with the first camera 120, that is, in a scanning direction that is the moving direction of the flat panel 200. [

Therefore, after inspecting for defects such as short, edge filming, stamping and scratching, the flat panel 200 can be separated and discharged from the inspection system to check for open defects. There is no need to shorten the inspection time for defects, which may also contribute to shortening the process time of the flat panel 200.

In addition, the flat panel 200 moves in a predetermined scanning direction with respect to the second camera 140, and the second camera 140 has a linear imaging region perpendicular to the scanning direction, which is the moving direction of the flat panel 200 The pattern of light-related plate elements present in the photographing area is photographed, and the photographed image is transmitted to the pattern inspecting unit 150.

As will be described later, the pattern inspector 150 may determine whether the defect is open with respect to the pattern of the light-related plate element through the image photographed by the second camera 140.

Meanwhile, the pattern inspecting unit 150 detects a pattern defect of the light-related plate element based on the images photographed by the first camera 120 and the second camera 140.

The pattern inspecting unit 150 changes the shape of the pattern such as short, edge filming, stamping, and scratch on the pattern of the light-related plate element based on the image photographed by the first camera 120. Based on the image photographed by the second camera 140, it is possible to determine whether a defect of the pattern of the optical-related plate element is open, that is, whether a part of the pattern is broken or not have.

In this case, the pattern inspecting unit 150 detects a portion having a value higher than a predetermined reference luminance in the pattern of the image photographed by the first camera 120 or the second camera 140, and applies the pattern to the pattern of the light-related plate element. Determine whether there is a defect.

Therefore, two or more different pattern defects can be detected by one inspection method (algorithm).

Detailed description thereof will be described later with reference to FIG. 5.

On the other hand, the focal length automatic adjustment unit 160 is applied to the focal length of the first camera 120 or the second camera 140 by falling down due to the load of the flat panel 200 or unevenness of the flat panel 200. If an error occurs for each camera, this is corrected for each camera so that the focal length of the first camera 120 or the second camera 140 can be maintained accurately.

To this end, the focal length automatic controller 160 stores the focal length of the first camera 120 or the second camera 140 in a memory, and when the flat panel 200 moves in the scanning direction by the conveyor, An optical signal such as a laser is irradiated onto the flat panel 200 before the first camera 120 is photographed and before the second camera 140 is photographed.

As a result, when a difference with a predetermined focal length of the first camera 120 or the second camera 140 occurs, the focal length automatic controller 160 adjusts the first camera 120 or the first as much as the generated difference value. 2 Camera 140 is adjusted up and down so that a predetermined focal distance can be accurately maintained.

For reference, the focal length automatic adjusting unit 160 may be configured in consideration of not only the focal length but also the focal position, the aperture value, and the moving speed of the flat panel 200 in the photographing areas of the cameras 120 and 140. One focal length can be adjusted.

For reference, the pattern inspection unit 150 and the focal length automatic control unit 160 according to the embodiment of the present invention refer to hardware components such as software, a field programmable gate array (FPGA), or an application specific integrated circuit (ASIC) , Play a role.

However, 'components' are not meant to be limited to software or hardware, and each component may be configured to reside on an addressable storage medium and configured to play one or more processors.

Thus, by way of example, an element may comprise components such as software components, object-oriented software components, class components and task components, processes, functions, attributes, procedures, Routines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables.

Components and the functionality provided within those components may be combined into a smaller number of components or further separated into additional components.

3A is a diagram illustrating a method of illuminating reflected light on an upper surface of a light-related plate element of the first light source 110 according to an embodiment of the present invention.

The first light source 110 may be located on one side of the first camera 120, and a half mirror 310 or a prism may be positioned on the front surface of the first light source 110.

Therefore, the light irradiated from the first light source 110 may be on the same line as the first camera 120 to illuminate light having strong straightness.

3B is a diagram illustrating a method of illuminating transmitted light on a bottom surface of a light-related plate element of the second light source 130 according to an embodiment of the present invention.

The second light source 130 may be positioned in a symmetrical position with the second camera 140 with the flat panel interposed therebetween, so that the lead 410 portion is dark and the portion 420 between the lead and the lead can obtain a bright image. It can be clearly distinguished.

4 is a view illustrating a pattern defect detection method of a light-related plate element of the pattern inspection unit 150 according to an embodiment of the present invention.

The pattern inspecting unit 150, for the lead 410 appearing as a dark portion in the pattern of the light-related plate element in the images taken by the cameras 120 and 140, and the bright portion 420 between the lead and the lead, respectively, Compare the brightness (luminance) with the surrounding pixels.

As shown in FIG. 4, the pattern inspecting unit 150 may display a result of comparing brightness of surrounding pixels with respect to the bright portion 420 between the leads 410 and the leads with the graph 430. When a defect occurs, it can be seen that the luminance 440 of the lead is very high compared to the predetermined luminance of the other leads.

Thereafter, the pattern inspecting unit 150 analyzes the defect generated through the binarization. At this time, the result data is the size of the generated defect (Dx, Dy), the number of defective pixels constituting the defect, the position of the defect in the pattern of the light-related plate element (centroid (X, Y)), the lead 410 Whether it is in the lead, whether it is in the lead, whether it is in the lead or not, and so on.

Therefore, the above-described inspection method (algorithm) can detect two or more different pattern defects such as short, edge filming, stamping, scratch and open in succession, It is possible to overcome the limitations of the prior art which had to use two inspection systems.

5A and 5B are actual images of defects detected by the pattern inspection unit 150 according to an embodiment of the present invention.

FIG. 5A is an image photographed by the first camera 120, and defects such as short, edge filming, stamping, and scratching were detected.

FIG. 5B is an example of detection of an open, which is an image photographed by the second camera 140. FIG.

6 is a flowchart illustrating a process of inspecting a pattern defect of a light-related plate element according to an embodiment of the present invention.

Hereinafter, the flowchart of FIG. 6 will be described with reference to the components of the apparatus shown in FIG. 2.

When the flat panel 200 starts to move in a predetermined scan direction with respect to the first camera 120 and the second camera 140 by a conveyor (not shown) or a robot (not shown), first, an automatic focal length adjusting unit ( 160 checks the focal length of the first camera and adjusts the first camera 120 up and down to maintain a predetermined focal distance when a predetermined focal length and error occur (S601).

After step S601, the first light source 110 illuminates the reflected light on the upper surface of the light related plate element, and the first camera 120 illuminates the upper surface of the light related plate element illuminated by the reflected light by the first light source 110. Shooting, and transmits the photographed image to the pattern inspection unit 150 (S602).

After step S602, the focal length automatic controller 160 checks the focal length of the second camera 140, and when a predetermined focal length and error occur, adjusts the second camera 140 up and down to determine the predetermined focus. To maintain the distance (S603).

After step S603, the second light source 130 illuminates the transmitted light on the lower surface of the light related plate element, and the second camera 140 photographs the upper surface of the light related plate element through which the transmitted light of the second light source 130 is transmitted. In operation S604, the captured image is transmitted to the pattern inspecting unit 150.

7, the focal length automatic adjustment unit 160 of the first camera and the illumination of the first light source 110 and the photographing of the first camera 120 are preceded, and thereafter the second The illumination of the focal length automatic adjustment unit 160 and the second light source 130 of the camera 140 and the photographing of the second camera 140 are performed. However, the process is not necessarily performed in this order, The illumination of the focal length automatic controller 160 of the second camera 140 and the second light source 130 and the photographing of the second camera 140 may be preceded.

After the step S604, the pattern inspecting unit 150 detects a portion having a value higher than a predetermined reference luminance in the pattern of the image photographed by the first camera 120 or the second camera 140, and determines the light-related plate element. It is determined whether the pattern is defective (S605).

Thereafter, the pattern inspecting unit 150 may transmit the data about the detected defect, that is, the size of the defect, the number of defective pixels constituting the defect, the position of the defect, etc. together with the captured image to the operator's terminal (S606). .

The foregoing description of the present invention is intended for illustration, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features of the present invention. will be.

It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is shown by the following claims rather than the above description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

110: first light source
120: the first camera
130: second light source
140: second camera
150: pattern inspection unit
160: focal length automatic adjustment unit
200: flat panel
310: half mirror
410: lead
420: bright part between lead and lead
430: brightness graph
440: luminance of the lead

Claims (7)

An apparatus for inspecting a pattern formed on a light-related plate element,
A first light source illuminating reflected light on an upper surface of the light-related plate element,
A first camera for photographing the upper surface illuminated by the reflected light,
A second light source illuminating the transmitted light on the lower surface of the light-related plate element,
A second camera for photographing an upper surface of the light related plate element through which the transmitted light is transmitted;
A pattern inspecting unit for detecting a portion having a value higher than a predetermined reference luminance in the pattern photographed by the first camera and the second camera to determine whether the pattern is defective;
A focal length automatic adjustment unit configured to automatically adjust at least one or more focal lengths of the first camera and the second camera,
The first camera and the second camera are disposed in succession with each other in the direction of movement of the flat panel comprising the light associated plate element,
The focal length automatic adjustment unit may be configured such that the first camera and the second camera are based on a distance between the first camera and the light related plate element, a distance between the second camera and the light related plate element, and a moving speed of the flat panel. Automatically adjust at least one of the focal lengths,
The pattern inspecting unit determines a first defect based on a pattern photographed by the first camera, and determines a second defect different from the first defect based on the pattern photographed by the second camera,
The photographing of the first camera and the photographing of the second camera are performed either in the photographing order of the second camera or in the reverse order after the photographing of the first camera.
Comprising a, pattern inspection apparatus.
The method of claim 1,
The pattern inspecting unit determines whether one or more of short, edge filming, stamping, and scratching are defective in the pattern photographed by the first camera.
The method of claim 2,
The pattern inspecting unit determines whether the defect due to the open (open) in the pattern photographed by the second camera.
The method of claim 3, wherein
And the pattern inspection unit simultaneously detects two or more different pattern defects with respect to the pattern of the light-related plate element photographed by the first camera and the second camera.
delete The method of claim 1,
The focal length automatic adjustment unit measures a distance between the first camera and the light-related plate element and distances between the second camera and the light-related plate element using a laser, wherein the values of the measured distances and a predetermined reference focal point are measured. Comparing the distance value, and moving the at least one of the first camera and the second camera up and down to correspond to the difference value, the pattern inspection apparatus. delete

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