KR102045818B1 - Transmissive optical inspection device and method of detecting defect using the same - Google Patents

Abstract

Optical system inspection apparatus of the embodiments of the present invention is arranged between the light source for irradiating the light to the object, the object and the light source to shield the light partially and the photographing to receive the light passing through the object to receive the image Contains wealth. Therefore, the defect of a test subject can be detected with high sensitivity.

Description

Transmission optical system and defect inspection method using the same {TRANSMISSIVE OPTICAL INSPECTION DEVICE AND METHOD OF DETECTING DEFECT USING THE SAME}

The present invention relates to a transmission optical inspection device and a defect inspection method using the same. More particularly, the present invention relates to a transmission optical inspection device and a defect inspection method using the same through the collection of light transmitted through the object.

Conventional visual inspection methods are automatically performed by a mechanical device through an automated facility. As an automated inspection device, the transmission optical inspection device is used to find surface defects of a material having a flat surface.

For example, glass and various optical films included as components of an image display device are required to have smooth and flat surfaces of the glass and optical film in order to improve the image output quality of the image display device.

In particular, in the case of optical films used in image display devices such as retarders, polarizers, retardation films, etc., the surface thereof needs to be extremely flat.

However, glass and optical films often have defects such as scratches, foreign matters, bubbles, irregularities, tearing, warping or folding on their surfaces during manufacture or handling.

It is necessary to detect these defects with high sensitivity in order to improve the image quality of the image display device. For example, Korean Unexamined Patent Publication No. 10-2017-0010675 discloses an optical film inspection apparatus, but has a limit in detecting even finer defects.

Korean Patent Publication No. 10-2017-0010675

One object of the present invention is to provide an optical inspection device having excellent detection resolution.

One object of the present invention is to provide a defect inspection method capable of detecting defects with high sensitivity.

1. A light source for irradiating light to the subject; A light blocking part disposed between the test object and the light source to partially block the light; And a photographing unit configured to receive light passing through the object under test and obtain an image.

2. In the above 1, further comprising a condensing lens disposed between the light source and the light shield, transmission optical system inspection apparatus.

3. In the above 2, wherein the condenser lens is disposed so that the focus is formed on the surface of the test object, transmission optical system inspection apparatus.

4. In the above 2, wherein the light shielding portion has a bar shape partially overlapping with the light source or the light collecting lens on a plane, transmission optical system inspection apparatus.

5. The transmission optical system inspection apparatus according to the above 4, wherein light incident to the inspected object vertically is blocked among the light passing through the condensing lens by the light blocking unit.

6. In the above 5, wherein the light source, the light collecting lens, the light shielding portion and the photographing portion are arranged in a line in a direction perpendicular to the object to be inspected, transmission optical system inspection apparatus.

7. In the above 1, wherein the light shielding portion is disposed perpendicular to the conveying direction of the inspected object on a plane, transmission optical system inspection apparatus.

8. In the above 7, wherein the light shielding portion is disposed inclined at an angle of more than 45 degrees ( ^o ) or less than 90 degrees with respect to the conveying direction of the inspected object on a plane, transmission optical system inspection apparatus.

9. The apparatus of claim 1, wherein the inspected object includes a scratch therein, and light diffracted through the scratch among unblocked light by the light blocking unit is collected in the imaging unit.

10. preparing a subject including a defect; Arranging a light blocking unit under the test object; Irradiating light to filter vertical light with respect to the inspected object through the light blocking unit; And collecting light diffracted through the defect to obtain an image.

In the optical inspection apparatus according to the embodiments of the present invention, the light from the light source to the shooting unit to go straight to the shooting unit may be blocked, the overall image may appear dark.

In the defective part of the object under test, the light reaching the defect may be accommodated in the photographing unit while the path of the light is changed by diffraction, scattering, or refraction.

Therefore, an image in which a portion without a defect appears dark and only a portion with a defect appears bright can be obtained, so that a defect of a minute size can be easily detected.

Further, by condensing light using a condenser lens, the amount of light reaching the defect can be increased without being blocked by the light shielding portion, thereby improving the detection sensitivity of the defect.

In addition, by arranging the light blocking part and the light source at a specific angle with respect to the transport direction of the inspected object, defects of various sizes and shapes that may be formed in various directions on the inspected object may be detected with a substantially uniform sensitivity. have.

1 and 2 are schematic views illustrating a transmission optical inspection apparatus according to exemplary embodiments.
3 and 4 are views showing a transmission optical system inspection apparatus according to a comparative example and an image image obtained therefrom.
5 to 7 are diagrams illustrating a transmission optical inspection apparatus and an image obtained therefrom, according to some embodiments.
8 to 10 are views illustrating a transmission optical inspection apparatus and an image obtained therefrom, according to some embodiments.

Embodiments of the present invention include a light source, a light shielding unit and a photographing unit, and the light shielding unit is disposed between the inspected object and the light source to provide a transmission optical system inspection apparatus that partially blocks the light. In addition, embodiments of the present invention provide an inspection method that can detect defects such as scratches (scratches) using the transmission optical inspection device.

Hereinafter, exemplary embodiments of the present invention will be described in more detail with reference to the accompanying drawings. However, the following drawings attached to the present specification are intended to illustrate preferred embodiments of the present invention, and together with the contents of the present invention serves to further understand the technical spirit of the present invention, the present invention described in such drawings It should not be construed as limited to matters.

As used herein, the term 'transfer direction of the subject' refers to the longitudinal direction of the subject on the plane of the subject.

1 and 2 are schematic views illustrating a transmission optical inspection apparatus according to exemplary embodiments.

1 and 2, the transmission optical system inspection apparatus 100 (hereinafter, abbreviated as inspection apparatus) may include a light source 110, a light blocking unit 150, and a photographing unit 190. According to example embodiments, the object 170 may be located between the imaging unit 190 and the light blocking unit 150.

The light source 110 may irradiate light onto the object 170. Non-limiting examples of the light source 110 include LEDs, metal halides, fluorescent, halogen, and the like. For example, the light source 110 may be rod-shaped or rod-shaped.

The object 170 may be disposed between the light source 110 and the photographing unit 190, and light may be irradiated from the light source 110. In addition, light that is not blocked by the light blocking unit 150 among the light emitted from the light source 110 may pass through the object 170 to be accommodated in the photographing unit 190.

The inspected object 170 may be, for example, a plate, film, or sheet-like material. For example, the inspected object 170 may be conveyed while being placed on a transparent conveyor belt or conveyed while the inspected object 170 is wound by a roller.

The inspected object 170 may include glass or an optical film. The optical film or the glass may be inserted into an OLED device, an LCD device, or the like. The optical film may include, for example, a polarizing plate, a retarder, an encapsulation film, a window film, a protective film, and a touch sensor film.

The inspected object 170 may include a defect, and the defect may include, for example, scratches, scratches, tears, chips, foreign matters, or folds, and is uneven and uneven on the surface of the inspected object 170. It may mean that there is a part. When a defect (for example, a scratch) exists in the inspected object 170, the path of the light reaching the defect may be changed by, for example, refraction, diffraction, or scattering.

The test object 170 may be a material having transparency or transparency, and may be a material having at least semitransparency. In addition, since the light propagation path may be changed by the diffraction or scattering, the light may travel to the photographing unit 190, and thus may be an opaque material.

The light blocking unit 150 may be disposed between the object 170 and the light source 110 to partially block the light. For example, the light blocking unit 150 may be disposed in parallel with the object 170. For example, light emitted from the light source 110 by the light blocking unit 150 may block light traveling substantially straight toward the photographing unit 190.

The light blocking unit 150 may be formed of a material that blocks light, and blocking light means that the light does not substantially pass through. For example, the light blocking unit 150 may be formed of a material having a light transmittance of less than 10%.

In addition, the light blocking unit 150 may be formed of, for example, a material that absorbs or reflects light. Non-limiting examples of the light shielding portion 150 may include a metal plate and an opaque plastic.

Partially blocking the light does not block all of the light, for example, may mean blocking 50% to 90% of the light.

When the blocking rate is within the above range, the amount of light is not excessively high, so that the background of the image acquired by the photographing unit 190 can be kept dark, and the amount of light is not too small so that the defect is brightly detected so that the inspection apparatus 100 can be detected. The detection force of can be secured.

The photographing unit 190 may acquire the image by receiving the light passing through the object 170. For example, an image may be acquired from light passing through the object 170 without being blocked by the light blocking unit 150. The photographing unit 190 may include, for example, a CCD camera, and may include, for example, a line-scan camera and an area camera.

For example, when light is received by the photographing unit 190, an image acquired through the photographing unit 190 may appear bright, and when no light is input, an image obtained through the photographing unit 190 may appear dark. have.

More specifically, FIG. 1 is a schematic view illustrating a case in which light is irradiated to a defect-free portion of the inspected object 170 in some embodiments, and FIG. 2 is a schematic view of the inspected object 170 in some embodiments. It is a schematic drawing which shows the case where light was irradiated to the defective part.

As shown in FIG. 1, when light is irradiated to a defect-free portion of the inspected object 170, light that is substantially straight toward the photographing unit 190 is blocked by the light blocking unit 150. Light propagating away from the light blocking unit 150 may reach the test object 170. The light may pass straight through the object 170. The straight line means that the propagation path of the light remains substantially unchanged, and may include, for example, a case where the light is refracted within a range of about 10 degrees.

In this case, the light may not be accommodated in the photographing unit 190. Therefore, the image acquired by the photographing unit 190 may appear dark.

On the other hand, as shown in FIG. 2, when light is irradiated to a defective part of the object 170, the light reaches the defect (for example, scratch) and is diffracted, scattered, or refracted. The path of travel of the light can be changed.

In this case, a part of the diffracted, scattered or refracted light may be accommodated in the image capturing unit 190, and an image obtained by the image capturing unit 190 may appear bright.

Therefore, when there is no defect in the object 170, the image may appear dark, and when there is a defect, the image may appear bright. Therefore, even if the defect part appears brightly on a dark background, the inspection apparatus 100 may easily detect even a minute defect of the inspected object 170.

3 and 4 are views showing a transmission optical system inspection apparatus according to a comparative example and an image image obtained therefrom.

Referring to FIG. 3, the transmission optical system inspecting apparatus 200 according to a comparative example includes a light source 210 and a photographing unit 290, and includes a light shielding film 150 included in the inspecting apparatus 100 according to embodiments. It does not have. Detailed descriptions of components and / or structures substantially the same as those described with reference to FIGS. 1 and 2 will be omitted.

When the light shielding unit 150 is omitted, light that travels substantially straight from the light source 210 toward the imaging unit 290 is received by the imaging unit 290 without being blocked. In this case, unlike the inspection apparatus 100 according to the exemplary embodiment, an excessively large amount of light accommodated in the photographing unit 290 may cause the image to be obtained to appear bright overall.

In the defective part of the inspected object 270, refraction, diffraction or scattering of light reaching the defect may occur. In this case, the light may travel away from the photographing unit 290 while the path of the light is changed. Thus, the defective portion may appear darker in the image.

A dark portion crossing the center of FIG. 4 in the vertical direction corresponds to the defect present in the inspected object 270, and appears darker than the portion without the defect.

Therefore, when the light blocking unit 150 is not provided, as shown in FIG. 4, the difference between the color and the brightness of the portion without the defect and the portion with the defect is not large, and thus the detection power of the defect may be low.

In some embodiments, the inspection apparatus 100 may further include a light collecting lens 130 disposed between the light source 110 and the light blocking unit 150. The condenser lens 130 has a function of condensing while passing straight light, for example, and may include a concave lens or the like.

The condenser lens 130 may be integrally formed with the light source 110 and included in the light source 110 as one member, and the light shield 150 may be integrated with the condenser lens and the light source 110 as one member. 110).

According to an embodiment, the condenser lens 130 may be disposed to form a focal point on the surface of the object 170.

When the focus is formed on the surface of the object 170, the amount of light reaching the defective portion may increase. Therefore, the amount of light whose path is changed by diffraction, scattering, or refraction in the defect may increase, and the amount of light received in the photographing unit 190 may also increase, thereby increasing the detection power of the defect.

In some embodiments, the light blocking part 150 may have a bar shape partially overlapping the light source 110 or the light collecting lens 130 on a plane.

For example, the light source 110 or the condenser lens 130 may also have the bar shape, and the light blocking part 150 having the bar shape is emitted from the light source 110 to condense through the condenser lens 130. The light can be evenly blocked in the longitudinal direction of the bar shape. Therefore, the detection power of the defect can be improved by reducing the amount of light accommodated in the photographing unit 190 to maintain the dark background.

In one embodiment, the light incident to the inspection object 170 of the light passing through the light collecting lens 130 by the light blocking unit 150 may be blocked.

The vertically incident light refers to light that is substantially vertically incident, and may include, for example, light that is refracted by the condensing lens 130 and is incident within a range of about 60 degrees to 90 degrees.

By blocking the vertically incident light, the background of the image obtained by adjusting the amount of light accommodated in the photographing unit 190 may not be excessive.

According to an exemplary embodiment, the light sources 110, the light collecting lenses 130, the light blocking units 150, and the photographing units 190 may be arranged in a line perpendicular to the object to be examined 170.

As shown in FIGS. 1 and 2, when the light source 110, the condenser lens 130, the light shielding unit 150, and the photographing unit 190 are arranged in this manner, a focal point is formed on the surface of the object 170. It is easy to, and as the light is incident symmetrically to the focal point, the detection power of defects formed in various directions can be increased.

5 to 7 are diagrams illustrating a transmission optical inspection apparatus and an image obtained therefrom, according to some embodiments.

In some embodiments, as shown in FIG. 5, the light blocking part 150 may be disposed perpendicularly to the transfer direction of the object 170 on a plane. The vertical means an angle that can be substantially recognized as an angle of 90 degrees, and may include, for example, an angle of 80 degrees to 100 degrees.

For example, the light source 110 may also be disposed in the same direction as the light blocking unit 150. Therefore, the amount of light irradiated with respect to the defect formed in the width direction of the inspected object 170 may increase, and thus, the detection force of the defect may be improved.

Thus, as shown in FIGS. 6 and 7, defects such as scratches formed in a thin linear shape can be easily identified on the obtained image, thereby improving the detection resolution of the defects.

8 to 10 are views illustrating a transmission optical inspection apparatus and an image obtained therefrom, according to some embodiments.

In some embodiments, as shown in FIG. 8, the light blocking part 150 may be disposed to be inclined at an angle of 45 degrees or more and less than 90 degrees with respect to the conveyance direction of the object 170 on a plane. In FIG. 8, an angle formed between the light blocking portion 150 and the conveyance direction of the inspected object 170 is represented by θ.

Defects may be formed in the object 170 in various directions and shapes. For example, when the defects are formed and the direction in which the light blocking film 150 and the light source 110 are disposed is substantially perpendicular, the defects may be reached. Since the amount of light is small, the detection power of a defect can be reduced.

For example, when the placement angle of the light blocking part 150 is an angle within the above range, both the defect formed in the conveying direction of the object 170 and the defect formed perpendicular to the conveying direction can be detected with high sensitivity. Therefore, defects formed in various directions and shapes can be detected universally (with substantially uniform sensitivity).

9 is an image obtained from the same part of the subject as shown in FIG. 6 and FIG. 10 is an image obtained from the same part of the subject as shown in FIG. 10 and 7 are images obtained from scratches formed in a direction parallel to the transfer direction of the inspected object.

Therefore, in the case of the scratch formed at a specific angle with respect to the conveying direction of the inspected object 170, as shown in FIG. 9 (compared to FIG. 6), the detection sensitivity may be further improved.

In addition, in the case of a scratch formed in parallel with the conveying direction of the inspected object 170, as illustrated in FIG. 10, the detection sensitivity may be more improved than in the image illustrated in FIG. 7.

According to some embodiments, the inspected object 170 may include a scratch therein, and light diffracted through the scratch among unblocked light by the light blocking unit 150 may be collected in the photographing unit 190. Accordingly, even a thin scratch may be detected by the inspection apparatus 100 by the diffraction, and thus the detection resolution may be improved.

In some embodiments, after preparing an inspected object including a defect and arranging a light shield under the inspected object, light may be irradiated to filter vertical light with respect to the inspected object through the light shield. In addition, the defect of the inspected object may be inspected by collecting the light diffracted through the defect to acquire an image.

100: optical system inspection device 110, 210: light source
130 and 230: condensing lens 150: light blocking part
170, 270: Subjects 190, 290: Shooting unit

Claims (10)

A light source for irradiating light onto the subject;
A condensing lens disposed between the light source and the inspected object so that the focus of the light is formed on the surface of the inspected object;
A light blocking part disposed between the light collecting lens and the test object and partially blocking the light; And
It includes a photographing unit for receiving the light passing through the test object to obtain an image,
The light source, the condenser lens, the light shielding portion and the photographing portion are arranged in a line, the transmission optical system inspection device.
delete delete The transmission optical system inspection device according to claim 1, wherein the light shielding portion has a bar shape partially overlapping with the light source or the condensing lens on a plane.
The transmission optical system inspection device according to claim 4, wherein light incident to the inspection object vertically is blocked among the light passing through the condensing lens by the light blocking portion.
The transmission optical system inspection device according to claim 5, wherein the light source, the condenser lens, the light shielding portion, and the photographing portion are arranged in a line in a direction perpendicular to the inspection object.
The said optical shielding part is a transmission optical system inspection apparatus of Claim 1 arrange | positioned on the plane perpendicular | vertical with respect to the conveyance direction of the to-be-tested object.
The system according to claim 7, wherein the light-shielding portion for a plane in the transport direction of the object to be inspected 45 ^(o) above 90 are arranged obliquely at an angle of less than, the transmission optical inspection apparatus.
The transmission optical system inspection apparatus according to claim 1, wherein the inspected object includes a scratch therein, and the light diffracted through the scratch among unblocked light by the light shielding portion is collected in the imaging unit.
Preparing a test subject including a defect;
Arranging a light blocking unit under the test object;
Arranging the light source, the condenser lens, the light blocking part, and the photographing part in a line in order;
Irradiating light to filter vertical light with respect to the inspected object through the light blocking part while forming a focus of the light on the surface of the inspected object through the condenser lens; And
And collecting the light diffracted by passing the defect through the photographing unit to obtain an image.

Images