KR20100059550A

KR20100059550A - Apparatus and method for inspecting flat panel

Info

Publication number: KR20100059550A
Application number: KR1020080118359A
Authority: KR
Inventors: 김기현; 박경자
Original assignee: 주식회사 매크론
Priority date: 2008-11-26
Filing date: 2008-11-26
Publication date: 2010-06-04

Abstract

Disclosed are a flat plate inspection apparatus and a method thereof. The light source unit is positioned laterally with respect to a plane including the surface of the inspection object to irradiate the inspection light pattern to the inspection object. The flat screen is installed at a position opposite to the light source unit with respect to the inspection object, and is positioned laterally with respect to a plane including the surface of the inspection object to form an image of the inspection light pattern reflected from the inspection object. The imaging unit is installed at a position opposite to the flat screen, and captures an image of the inspection light pattern formed on the flat screen to output an inspection image. The determination unit evaluates the degree of warpage of the inspection object based on the inspection image. According to the present invention, it is possible to evaluate the degree of warpage of the flat plate without optical distortion by converting the structure of the inspection system in which only the side of the inspection target plate can be taken sideways due to spatial constraints so as to enable front-side imaging. Defect detection is possible at an early stage.

Description

Apparatus and method for inspecting flat panel

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat panel inspection apparatus and a method thereof, and more particularly, to an inspection apparatus and method for evaluating the degree of warpage of a flat plate such as a bare glass used in a flat panel display apparatus.

Flat panel display devices such as LCDs and OLEDs basically produce products in a structure of forming a thin film on the bare glass, and thus, the quality of the bare glass determines the basic quality of various flat panel display products. The size of the bare glass of products such as LCDs continues to grow, and the width of the bare glass is expected to increase to 2880 mm in the future. As the width of the bare glass increases, the possibility of the bare glass bent during the production of the bare glass increases. If the degree of warpage of the bare glass becomes greater than the quality control standard value, not only may the glass be scratched or broken in the process step after the bare glass is formed, but also the quality of the product of the flat panel display company producing the product using the bare glass. It will also affect.

The bare glass is manufactured to have a desired width, length and thickness by processing the molten glass through the forming apparatus, the molten glass is molded in the form of a glass sheet through the forming apparatus as shown in FIG. Discharged downward. At this time, the shielding space where the forming apparatus is located is maintained at a high temperature between 700 degrees Celsius and 800 degrees Celsius, and thus the inspector makes a glass sheet made by the forming apparatus through a glass window provided in the shielding space as shown in FIG. 2. Visually check for bending. However, since there is a limit to the accuracy of the measurement that can be obtained by visual inspection, attempts to measure this automatically have been made. However, the internal temperature of the shielded space is so high that, like the current operator's viewing position, the automatic measuring device has to be placed outside the shielded space, and only the side view of the glass sheet is possible through the limited sized glass window.

Regarding the automation of such a flat plate inspection apparatus, the thin film type inspection object inspection apparatus described in Korean Patent Laid-Open Publication No. 10-2006-0108829 has been proposed. However, since the device is configured to project a specific pattern on the thin film type test object and directly image the irradiated pattern, it is difficult to obtain an image that is easy to analyze in the case of transparent bare glass having high transmittance. In addition, as shown in FIG. 3, when the illumination and the camera are installed on the side of the bare glass, the difference between the distances L1 and L2 between the both ends of the glass sheet and the imaging camera is large when the glass sheet is captured. There is a problem that it is difficult to focus the lens evenly, and as a result, the accuracy of the measurement is lowered. This problem becomes larger as the size of the bare glass increases.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a flat panel inspection apparatus and method capable of inspecting a warp state of a flat plate without optical distortion while solving a problem of defocus caused when the flat surface to be inspected is directly photographed. .

According to an aspect of the present invention, there is provided a flat plate inspection apparatus, comprising: a light source unit positioned in a lateral direction with respect to a plane including a surface of an inspection object and radiating an inspection light pattern to the inspection object; A flat screen installed at a position opposite to the light source unit with respect to the inspection object and positioned in a lateral direction with respect to a plane including the surface of the inspection object to form an image of an inspection light pattern reflected from the inspection object; An imaging unit installed at a position opposite to the flat screen and configured to photograph an image of a test light pattern formed on the flat screen to output a test image; And a determination unit for evaluating the degree of warpage of the inspection object based on the inspection image.

According to another aspect of the present invention, there is provided a flat plate inspection method according to an embodiment of the present invention, wherein the inspection object is set at a time interval set based on a moving speed of the inspection object in a state in which the inspection object is discharged below the forming apparatus. Irradiating the inspection light pattern on the; Photographing an image of an inspection light pattern formed on a flat screen provided on a side of the inspection object corresponding to an irradiation time of the inspection light pattern; And evaluating the bending degree of the inspection object based on the distortion degree of the inspection light pattern detected from the photographed inspection image.

According to the flat panel inspection apparatus and method according to the present invention, the installation position of the automatic inspection apparatus according to the characteristics of the sealed chamber in which the flat plate such as bare glass is made (that is, the high temperature inside the sealed chamber and the narrowness of the space) By placing the flat screen between the flat plate and the camera in the presence of spatial constraints (i.e., the flat plate inspection device must be located on the side of the plate being the inspection object and outside of the sealed chamber), without distortion of the optical system. The degree of warpage of the plate can be accurately assessed, enabling defect detection at an early stage of plate production. In addition, by placing the light source and the camera emitting the inspection light in the same space outside the sealed room, there is an advantage that can be prevented from damaging the materials constituting the flat plate inspection apparatus.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the flat plate inspection apparatus and method according to the present invention.

4 and 5 are views showing the configuration of a preferred embodiment of a flat plate inspection apparatus according to the present invention.

4 and 5, the flat panel inspection apparatus according to the present invention includes a light source unit 410, a flat screen 420, an imaging unit 430, and a determination unit 440.

The light source unit 410 is positioned laterally with respect to a plane including the surface of the inspection object (eg, bare glass) 400 to irradiate the ray light source to the inspection object 400. Since the flat panel inspection apparatus according to the present invention evaluates the degree of warpage of the inspection target object 400 based on the degree of distortion of the pattern photographed by the imaging unit 430, the light irradiated from the light source unit 410 to the inspection object 400. It is preferable to have the form of a linear light source. In addition, the line light source is preferably formed by laser light to obtain a clearer and more accurate image, and further, in order to measure the overall bending degree and the partial bending degree of the inspection object 400 by a single shot, the light source unit 410. It is preferable to irradiate the inspection object 400 with a plurality of linear light sources that are constantly spaced apart from each other. At this time, the line light source is irradiated to the inspection object 400 to be perpendicular to the moving direction of the inspection object 400, the length of the line light source is set equal to or longer than the width of the inspection object 400.

If the bare glass manufactured by being discharged downward from the forming apparatus is the inspection object 400, the light source unit 410 may fix one line light source according to the moving speed of the inspection object 400, rather than irradiating a plurality of line light sources. Irradiation at intervals is preferable. 5 illustrates various types of light patterns irradiated from the light source unit 410 to the inspection object 400. The rectangular light pattern of the light pattern shown in FIG. 6 has the advantage of inspecting both the degree of warp in the vertical and horizontal directions of the inspection object 400. The light source unit 410 may be located inside a sealed room where the bare glass, which is the inspection object 400, is manufactured. However, the light source unit 410 may be installed outside the sealed room to facilitate maintenance and management of the light source unit 410. It is preferable to configure so that light is irradiated to the inspection object 400 located inside the closed chamber through the window.

The flat screen 420 is installed at a position opposite to the light source unit 410 with respect to the inspection object 400 and is positioned laterally with respect to a plane including the surface of the inspection object 400. At this time, the flat screen 420 is installed so that the plane including the surface perpendicular to the plane including the surface of the inspection object 400, at the same angle as the incident angle of the light irradiated from the light source unit 410 to the inspection object 400 It is installed on the path of the reflected light reflected. In addition, the flat screen 420 is controlled to be separated from the inspection object 400 so that the entire image of the reflected light reflected from the inspection object 400 is formed. The flat screen 420 is preferably a white surface in order to make the image of the reflected light more clearly, and is preferably installed inside the sealed chamber to minimize distortion of the image formed. Therefore, the flat screen 420 should be made of an opaque material that can be guaranteed durability even at a high temperature of about 700 ~ 800 ℃. In addition, the surface roughness of the flat screen 420 should be small to prevent distortion of the image, more specifically, it is preferable to have a surface roughness better than the surface roughness of the inspection object 400.

The imaging unit 430 is installed at a position opposite to the flat screen 420. The imaging unit 430 is preferably formed of an area camera for faster inspection, and in order to minimize distortion of the photographed inspection image, the focus of the imaging unit 430 may be adjusted to be formed at the center of the flat screen 420. There is a need. The imaging unit 430 may also be located inside the sealed room where the bare glass, which is the inspection object 400, is manufactured. However, in order to facilitate maintenance and management, the imaging unit 430 may be installed outside the sealed room and the flat screen may be installed through a window installed in the sealed room. It is preferable to photograph the image formed at 420. On the other hand, if the bare glass manufactured by being discharged downward from the forming apparatus is the inspection object 400, the imaging unit 430 synchronizes the imaging cycle with the line light source irradiation period of the light source unit 410 to display an image formed on the flat screen 420. Shoot. The control signal for matching the light irradiation period of the light source unit 410 with the imaging period of the imaging unit 430 may be provided by the light source unit 410 to the imaging unit 430 or a separate control device (not shown) may be used as the light source unit 410. And the imaging unit 430.

The determination unit 440 evaluates the degree of warpage of the inspection object 400 based on the inspection image acquired by the imaging unit 430. 7A and 7B illustrate examples of inspection images acquired by the imaging unit 430, respectively. The evaluation of the bending degree is made through the image processing technology such as the line detection through the edge detection from the inspection image, the curvature evaluation of the detected line, such image processing technology if one of ordinary skill in the art Detailed description is omitted since it is well understood. In addition, the determination unit 440 may determine the curvature obtained through the image processing process based on the reference value (for example, the range of the curvature value set corresponding to the size of the inspection object and the inspection object) set for each inspection object 400. Outputs the inspection result for the inspection object in comparison with the range of curvature values set for the purpose of use.

8 is a flowchart illustrating a process of performing a preferred embodiment of the plate inspection method according to the present invention.

Referring to FIG. 8, in the state where the bare glass 400 is discharged below the forming apparatus, the light source unit 410 installed outside the sealed chamber in which the forming apparatus is located irradiates the linear light source with the bare glass 400 ( S700). Next, the image capturing unit 430 installed at the outside of the sealed chamber is reflected by the bare glass in accordance with the irradiation period of the line light source by the light source unit 410, and photographs an image formed on the flat screen 420 to output an inspection image. (S710). Finally, the determination unit 440 calculates the curvature of the line detected from the inspection image input from the imaging unit 430 to evaluate the degree of bending of the bare glass 400 (S720). Steps S700 to S720 are repeatedly performed a plurality of times at regular time intervals to inspect the entire area of one bare glass 400 by a single linear light pattern. Unlike this, steps S700 and S710 may be repeated a plurality of times at regular time intervals, and step S720 may be performed once.

Although the preferred embodiments of the present invention have been shown and described above, the present invention is not limited to the specific preferred embodiments described above, and the present invention belongs to the present invention without departing from the gist of the present invention as claimed in the claims. Various modifications can be made by those skilled in the art, and such changes are within the scope of the claims.

1 is a view showing a state in which a molten glass is molded in the form of a glass sheet and discharged downward of a forming apparatus through a forming apparatus in a manufacturing process of a bare glass;

2 is a view showing an example of performing a conventional visual inspection,

FIG. 3 is a view showing an example of a conventional flat inspection apparatus having a configuration in which a camera installed at a position opposed to illumination based on a bare glass directly photographs a bare glass;

4 and 5 are views showing a preferred embodiment of the flat plate inspection apparatus according to the present invention,

6 is a view showing the form of the inspection light pattern used in the flat inspection apparatus according to the present invention,

7A and 7B are views illustrating inspection images of bare glass with almost no warpage and inspection images of bare glass having a high degree of warpage, respectively, photographed by the flat plate inspection device according to the present invention; and

Claims

A light source unit positioned in a lateral direction with respect to a plane including a surface of an inspection object and radiating an inspection light pattern to the inspection object;

A flat screen installed at a position opposite to the light source unit with respect to the inspection object and positioned in a lateral direction with respect to a plane including the surface of the inspection object to form an image of an inspection light pattern reflected from the inspection object;

An imaging unit installed at a position opposite to the flat screen and configured to photograph an image of a test light pattern formed on the flat screen to output a test image; And

And a determination unit for evaluating the bending degree of the inspection object based on the inspection image.

The method of claim 1,

And the inspection object is a bare glass which is molded by a molding apparatus located in an airtight chamber and discharged below the molding apparatus.

The method according to claim 1 or 2,

The light source unit irradiates a single linear inspection light pattern to the inspection object perpendicular to the moving direction of the inspection object at a time interval set based on the movement speed of the inspection object.

And the imaging unit captures an image of the inspection light pattern formed on the flat screen in response to the irradiation time of the linear inspection light pattern by the light source unit.

The method according to claim 1 or 2,

And the light source unit and the imaging unit are installed outside the sealed chamber in which the molding apparatus for molding the test object is located, and the flat screen is installed inside the sealed chamber.

Irradiating an inspection light pattern on the inspection object at a time interval set based on a moving speed of the inspection object in a state where the inspection object is discharged downwardly from the forming apparatus;

Photographing an image of an inspection light pattern formed on a flat screen provided on a side of the inspection object corresponding to an irradiation time of the inspection light pattern; And

And evaluating the bending degree of the inspection object based on the distortion degree of the inspection light pattern detected from the photographed inspection image.

The method of claim 5,

The inspection light pattern is a line light source irradiated to the inspection object perpendicular to the moving direction of the inspection object,

The distortion degree of the inspection light pattern is calculated by the curvature of the line detected from the photographed inspection image.