WO2011083989A2

WO2011083989A2 - Defect inspection device

Info

Publication number: WO2011083989A2
Application number: PCT/KR2011/000086
Authority: WO
Inventors: 이제선; 장기수; 최백영
Original assignee: 주식회사 쓰리비시스템
Priority date: 2010-01-07
Filing date: 2011-01-06
Publication date: 2011-07-14
Also published as: WO2011083989A3; KR101151274B1; KR20110080725A

Abstract

The defect inspection device of the present example comprises: a first light source for shining a first light onto an inspection object; a retroreflective plate which retroreflects the first light reflected from the inspection object such that the first light again falls incident on the inspection object; a second light source which shines a second light onto the inspection object; and a camera which captures an image of the inspection object from the first light, which has been retroreflected and made to again fall incident on the inspection object by means of the retroreflective plate, and the second light emitted from the second light source.

Description

Defect inspection device

An embodiment of the present invention relates to a defect inspection apparatus, which irradiates light to an object to be inspected, and is capable of detecting defects such as identification of foreign matters attached to the surface to which light is irradiated, and stamping, wrinkles, or discoloration of the irradiation surface. It relates to an inspection apparatus.

Optical films, which are mainly used in the flat panel display industry, cause defects in manufacturing and handling processes, and defects in optical films are factors that lower efficiency of LCD panels and PDP modules. In order to prevent the optical film having such defects from being used as it is in a display device, optical film manufacturers are carrying out an inspection process, and are using a device using visual inspection and vision by an operator.

The inspection of the optical film is a kind of final inspection performed after the manufacturing process of the optical film is completed. Therefore, various defects that may occur in the manufacturing process should be detected. Preventing the leakage of defective products through accurate image acquisition and automatic inspection process is an important technical task.

In order to cope with various defects, an image acquisition method should be used differently according to the defect type, and the quantity of optical system for image acquisition of defects should be set in accordance with the applied image acquisition method and installed in the inspection equipment.

When the optical film is sequentially put into the automatic inspection equipment, the optical film is transferred using a conveyor, a roll, and the like, and each optical system acquires an image suitable for its role while passing through a plurality of optical systems during the transfer.

1 is a view showing an example of a conventional defect inspection apparatus, Figure 2 is a view showing another example of a conventional defect inspection apparatus.

Referring to FIG. 1, a defect inspection apparatus is a device for inspecting a defect of an inspection object, which is mainly an opaque panel 2, wherein the light source 20 is moved to the opaque panel when the opaque panel 2 is moved by a conveyor 30. The light is irradiated at an oblique angle to (2), and the camera 10 receives light reflected from the opaque panel 2 to perform line scanning of the opaque panel 2.

And, referring to Figure 2, the defect inspection apparatus is a device for inspecting the defects on the inspection object, which is mainly a transparent panel 3, the conveyor 30 is formed in the slit 31, the slit of the conveyor 30 A transparent panel 3 is placed on the upper portion 31. In addition, a light source 20 is disposed below the slit 31, and the light emitted from the light source 20 passes through the slit 31, and the camera 10 passes through the slit 31. Line scanning is performed by receiving light.

In the conventional defect inspection apparatus, since the irradiation direction of the light irradiated from the light source is irradiated at a plurality of positions, there is a problem that it is difficult to distinguish the shape of the defect from the shadow. In addition, since the amount of light is insufficient to reach the camera efficiently, the light intensity of the light source should be increased. However, since scattering increases due to the increased light intensity, a clear image cannot be obtained. In order to prevent such a light loss phenomenon, a condensing illumination device must be constructed by installing a condenser lens on the light source, but even in the case of such a condensing illumination device, since the secondary light loss cannot be prevented, there is still a problem that the light efficiency is lowered. have.

The present embodiment is to solve such a conventional problem, and to propose a defect inspection apparatus to easily determine whether a defect is generated by acquiring a clearer image of the inspection object.

The defect inspection apparatus of the proposed embodiment includes a first light source for irradiating a first light to the inspection object; A retroreflective plate for retroreflecting the first light reflected from the inspection object, thereby allowing the first light to be reincident to the inspection object; A second light source for irradiating a second light to the inspection object; A light conversion unit collimating the second light so that the collimated second light is incident on the inspection object; And a camera which acquires an image of the inspection object from the first light recursively reflected by the retroreflective plate and re-entered into the inspection object and the second light passing through the light conversion unit.

The light conversion unit may include a collimator for collimating the second light, and a diffuser for dispersing the second light collimated by the collimator.

The retroreflective plate retroreflects the first light in the same direction as the incidence path of the first light to the first light reflected by the test object, thereby allowing the first light to be reincident to the test object. .

The angle at which the first light emitted from the first light source forms the light irradiation surface of the inspection object is different from the angle at which the second light emitted from the second light source forms the light irradiation surface of the inspection object. Is formed.

The apparatus may further include an image processor configured to receive at least one image captured by the camera and perform image processing of the inspection object, wherein the image processor comprises a first image captured by the first light from the camera. And a second image captured by the second light, and synthesizes the first image and the second image.

A defect inspection apparatus according to another embodiment of the present invention, the first light source for irradiating the first light to the inspection object; A retroreflective plate for re-reflecting the first light passing through the inspection object, thereby allowing the first light to be reincident to the inspection object; A second light source for irradiating a second light to the inspection object; And a camera for acquiring an image of the inspection object from a first light that is re-entered into the inspection object by the retroreflective plate and passes through the inspection object, and a second light emitted from the second light source and passing through the inspection object. It includes;

According to the defect inspection apparatus of this embodiment, the defects on the inspection object are summed by adding up the background part of the image acquired by the light retroreflected by the retroreflective plate and the defect part of the image acquired by the collimated and diffused light. It is possible to obtain a clear image for.

In addition, according to the drawback inspection apparatus of the present invention, by using a slit portion for reducing the interference of light of various paths, it is possible to increase the light efficiency.

In addition, according to the defect inspection apparatus of the present invention, by providing a light conversion unit for collimating and dispersing the light irradiated from the second light source, it is possible to minimize the change in the position of the illumination with respect to vibration to maintain a uniform brightness.

1 is a view showing an example of a conventional defect inspection apparatus.

2 is a view showing another example of a conventional defect inspection apparatus.

3 is a view showing a defect inspection apparatus according to an embodiment of the present invention.

4 is a view showing in detail the light conversion unit of the defect inspection apparatus of FIG.

FIG. 5 is a diagram showing an example of defects picked up by the defect inspection apparatus of FIG. 3; FIG.

6 is a view showing a defect inspection apparatus according to another embodiment of the present invention.

Hereinafter, a defect inspection apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

Figure 3 is a view showing a defect inspection apparatus according to an embodiment of the present invention, Figure 4 is a view showing in detail the light conversion unit of the defect inspection apparatus of Figure 3, Figure 5 is taken by the defect inspection apparatus of Figure 3 It is a figure which shows an example of a fault.

First, the configuration of the defect inspection apparatus 100 according to the present embodiment is shown in Figure 3, the defect inspection apparatus 100 by irradiating two different light to the inspection object, to provide a clear image of the defect Can be obtained.

3 to 5, the defect inspection apparatus 100 includes a first light source 110 that emits first light, a retroreflective plate 120, and a second light source 130 that emits second light. And a light converter 140, a camera 150, a slit 160, and an image processor 170. In the following description, the case where the said test target object is the optical film 1 is demonstrated as an example.

The first light source 110 irradiates the first light to the optical film 1, and the first light source 110 may be coaxially installed at an inlet side of the camera 150 to be described later. The first light source 110 may be configured as a high power LED lighting unit.

The retroreflective plate 120 is a member that retroreflects incident light in the same direction as the incident direction. The light emitted from the first light source 110 is reflected by the optical film 1 and is incident on the retroreflective plate 120, and the light incident on the retroreflective plate 120 is an inspection object in the same direction as the incident direction. It retroreflects to the optical film 1 side.

The second light source 130 also emits light toward the optical film 1 side, and may be configured as a high power LED lighting unit. The angle between the optical axis of the first light source 110 and the light irradiation surface of the optical film 1 is different from the angle between the optical axis of the second light source 130 and the light irradiation surface of the optical film 1. . For example, the path L1 (optical axis) of the light emitted from the first light source 110 is formed to be inclined approximately 45 degrees to 50 degrees with respect to the light irradiation surface of the optical film 1 (α), and the second light source The path L2 (optical axis) of the light emitted from 130 is formed to be inclined at about 10 to 20 degrees with the optical film 1 (β).

The light converting unit 140 collimates and disperses the light emitted from the second light source 130, and includes a collimator 141 and a diffuser 142. The light emitted from the second light source 130 is collimated while passing through the collimator 141, and the light is diffused in the left and right directions while passing through the diffuser 142.

In place of the light conversion unit 140 that collimates and disperses the light emitted from the second light source 130, when a general condensing lens is used, the position of the illumination is severely changed due to vibration and uniformity. It is difficult to maintain strength. Therefore, since the size of the defect on the optical film 1 may be distorted, it is necessary to configure the light conversion unit 140.

The camera 150 detects a defect on the optical film 1 by acquiring an image of the optical film 1. The light retroreflected by the retroreflective plate 120 is incident to the optical film 1 side, and the light is reflected by the optical film 1 to be incident to the camera 150.

The light emitted from the second light source 130 is also incident on the optical film 1, and the light is reflected by the optical film 1 and is incident on the camera 150. The camera 150 may acquire an image of the optical film 1 by using the light retroreflected by the retroreflective plate 120 and the light of the second light source 130.

The camera 150 may be a line camera, an area camera, or the like, and various image capturing means may be used in the optical film inspection apparatus.

The slit 160 is to reduce interference of light of various paths and is disposed above the optical film 1. The light emitted from the first light source 110, the light retro-reflected by the retroreflective plate 120, and the light emitted from the second light source 130 pass through the slit part 160 to pass through the optical film 1. ) Is incident. In addition, the light reflected from the optical film 1 also passes through the slit 160 and then enters the retroreflective plate 120 or the camera 150.

The image processor 170 synthesizes an image captured by the light retroreflected by the retroreflective plate 120 and an image captured by the light emitted from the second light source 130 and reflected by the optical film 1. do. The image captured by the light retroreflected by the retroreflective plate 120 and the image emitted by the second light source 130 and reflected by the optical film 1 are captured by the first light source 110 and The second light source 130 may be simultaneously driven and obtained, or the first light source 110 and the second light source 130 may be alternately driven as necessary.

Images having the first light source 110 and the second light source 130 as sources are transferred from the camera 150 to the image processor 170, and the defect image processed by the image processor 170 is illustrated in FIG. 5. Is shown.

In FIG. 5, three images are shown. In the image I10 on the uppermost side, light emitted from the first light source 110 passes through the optical film 1, the retroreflective plate 120, and the optical film 1. The image obtained by being incident to 150, the first image I10 by the first light source 110 includes an image I11 of a defect portion and an image I12 of a background portion, and includes an image of the defect portion ( I11) is simply dark in its entirety, making it difficult to distinguish whether it is a depressed image or a contaminant.

The second image I20 in the center of FIG. 5 is obtained by the light emitted from the second light source 130 entering the camera 150 through the light conversion unit 140 and the optical film 1. It is a video. The second image I20 also includes an image I21 of a defect portion and an image I22 of a background portion, wherein the image I22 of the background portion is displayed in overall darkness, and the image I21 of the defect portion is a second image. The area irradiated with light emitted from the light source 130 is brightly displayed.

Therefore, when the image I12 of the background portion of the image I10 by the first light source 110 and the image I21 of the defect portion of the image I20 by the second light source 130 are synthesized, As the three-dimensional effect of the image is clearly revealed, it is possible to clearly distinguish whether it is recessed or pollutant.

In FIG. 5, the lower third image I30 is an image obtained by combining the background area I12 of the first image I10 and the defect area I21 of the second image I20. I30 includes a bright background region I32 as a whole and a defect region I31 that appears more clearly.

The defect inspection apparatus according to the present embodiment configured as described above is configured by summing a defect portion of an image acquired by collimated and diffused light and a background portion of an image acquired by light retroreflected by a retroreflective plate. In addition, the effect of obtaining a clear image of the defect on the inspection object can be obtained.

In addition, the defect inspection apparatus according to the present embodiment configured as described above, by using the slit portion for reducing the interference of light of various paths, it is possible to obtain the effect of increasing the light efficiency.

In addition, the defect inspection apparatus according to the present embodiment configured as described above has a light conversion unit for collimating and dispersing the light irradiated from the second light source, thereby minimizing the change in the position of the illumination with respect to the vibration to achieve a uniform brightness A sustainable effect can be obtained.

On the other hand, Figure 6 is a view showing a defect inspection apparatus according to another embodiment of the present invention. In FIG. 6, members referred to by the same reference numerals as the members illustrated in FIGS. 3 to 5 have the same configuration and function, and detailed descriptions thereof will be omitted.

Referring to FIG. 6, the defect inspection apparatus 200 according to the present embodiment includes a first light source 110, a retroreflective plate 220, a second light source 130, a light conversion unit 140, and a camera ( 250, a slit 160, and an image processor 270.

The retroreflective plate 220 is a member that retroreflects incident light in the same direction as the incident direction. The light emitted from the first light source 110 passes through the optical film 1 and is incident on the retroreflective plate 220. The light incident on the retroreflective plate 220 is directed toward the optical film 1 in the same direction as the incident direction. Retroreflective.

The camera 250 detects a defect on the optical film 1 by acquiring an image of the optical film 1. Light retroreflected by the retroreflective plate 220 passes through the optical film 1 and is incident on the camera 250.

The light emitted from the second light source 130 is incident to the optical film 1 through the light conversion unit 140, and the light is transmitted to the camera 250 through the optical film 1. An image of the optical film 1 may be obtained by using the light retroreflected by the retroreflective plate 220 and the light of the second light source 130.

The image processor 270 captures an image of a background portion of the image captured by the light retroreflected by the retroreflective plate 220 and light transmitted from the second light source 130 to pass through the optical film 1. The images of defects are summed up among the images.

The embodiment of the present invention is applicable to an apparatus capable of confirming whether a defect of an object to be inspected by acquiring an image of the surface of the object to be inspected, and thus has industrial applicability.

Claims

A first light source for irradiating the first light to the inspection object;

A retroreflective plate for retroreflecting the first light reflected from the inspection object, thereby allowing the first light to be reincident to the inspection object;

A second light source for irradiating a second light to the inspection object; And

And a camera acquiring an image of the object to be inspected from the first light recursively reflected by the retroreflective plate and re-entered into the object to be inspected and the second light emitted from the second light source.
The method of claim 1,

Further comprising a light conversion unit for collimating the second light,

And the light conversion unit includes a collimator for collimating the second light, and a diffuser for dispersing the second light collimated by the collimator.
The method of claim 1,

The retroreflective plate retrospectively reflects the first light in the same direction as the incident path of the first light to the first light reflected from the inspection object, thereby allowing the first light to be reincident to the inspection object. Device.
The method of claim 1,

The angle at which the first light emitted from the first light source forms the light irradiation surface of the inspection object,

And a second light emitted from the second light source is different from an angle formed by the light irradiation surface of the inspection object.
The method of claim 1,

The defect inspection apparatus is provided with the first light source in an area facing the inspection object in the camera.
The method of claim 1,

And a video processor configured to receive at least one image captured by the camera and perform image processing of the test object.
The method of claim 6,

And the image processor receives a first image captured by the first light and a second image captured by the second light from the camera, and synthesizes the first image and the second image.
The method of claim 7, wherein

The image processor divides the first image and the second image into a defect region and a background region, extracts a background region from the first image, and extracts and synthesizes a defect region from the second image, thereby performing the synthesis. The defect inspection apparatus which acquires the defect image of a defect.
A first light source for irradiating the first light to the inspection object;

A retroreflective plate for re-reflecting the first light passing through the inspection object, thereby allowing the first light to be reincident to the inspection object;

A second light source for irradiating a second light to the inspection object; And

A camera which acquires an image of the inspection object from the first light which is re-entered into the inspection object by the retroreflective plate and passes through the inspection object and the second light emitted from the second light source and passes through the inspection object; Defect inspection apparatus comprising a.
The method of claim 9,

And a light converting unit collimating the second light before the light emitted from the second light source enters the inspection object.
The method of claim 9,

And an image processor which receives at least one image captured by the camera and performs image processing of the inspection object.

And the image processor receives a first image captured by the first light and a second image captured by the second light from the camera, and synthesizes the first image and the second image.
The method of claim 11,

The image processor divides the first image and the second image into a defect region and a background region, extracts a background region from the first image, and extracts and synthesizes a defect region from the second image, thereby performing the synthesis. The defect inspection apparatus which acquires the defect image of a defect.
The method according to claim 1 or 9,

The defect inspection apparatus disposed on the inspection object, further comprising a slit portion through which the first light and the second light pass.