KR102610300B1 - Defect detection device - Google Patents

Abstract

The present invention relates to a defect detection device, and according to one aspect of the present invention, there is provided: a first light source that irradiates light with a predetermined wavelength; a second light source that radiates light having a different wavelength from the first light source; an optical camera that captures light emitted from the first light source and the second light source reflected on an object to detect defects; and a controller that detects defects on the surface of the object by processing the image captured by the optical camera.

Description

Defect detection device {DEFECT DETECTION DEVICE}

The present invention relates to a defect detection device, and more specifically, to a defect detection device that captures reflected light using an optical camera and processes the captured image to detect defects.

It is necessary to detect defects on the surface of objects with smooth and reflective materials, such as glass, thin films, semiconductor wafers, plastic plates, or steel plates. However, due to the reflective characteristics of the surface of such an object, it is not easy to obtain an image of the surface using a general defect detection device.

Therefore, conventionally, defects on the surface are detected by acquiring images by shooting several to dozens of imaging devices from various angles. However, as the number of imaging devices increases, there is a problem that more costs are required to detect defects. .

In particular, in the case of products that are transparent, thin, and highly reflective of light, such as ultra-thin glass, polyimide film, and smartphone cover glass, there is a lot of detection error when inspecting with conventional technology, and it is impossible to distinguish between true defects and false defects. . Therefore, there is a problem with the operator directly visually inspecting the product.

Republic of Korea Patent No. 10-1150755 (May 22, 2012) Republic of Korea Patent No. 10-1203210 (2012.11.14.) Japanese Patent Publication No. 2008-164324 (2008.07.17.)

Embodiments of the present invention were invented against the above background, and are intended to provide a defect detection device capable of detecting defects on the surface of an object with reflective characteristics.

According to one aspect of the present invention, a first light source that radiates light having a predetermined wavelength; a second light source that radiates light having a different wavelength from the first light source; an optical camera that captures light emitted from the first light source and the second light source reflected on an object to detect defects; and a controller that detects defects on the surface of the object by processing the image captured by the optical camera.

The controller may control the first light source and the second light source to adjust the time difference in which light is emitted from the first light source and the second light source, respectively.

The optical camera includes a first lens that focuses light reflected from each object; a second lens that condenses the light transmitted through the first lens; a light blocking plate disposed between the first lens and the second lens and blocking a portion of light passing through the first lens; And it may include an image sensor that receives light passing through the second lens and outputs an electrical image signal from the incident light.

At least one of the first light source and the second light source may include a plurality of lamps.

At least one of the first light source and the second light source includes one lamp, and the one lamp may have a predetermined length.

The first light source and the second light source may be included in one module.

The first light source and the second light source may be formed integrally.

The first light source and the second light source may radiate light to the object at the same angle.

The first light source and the second light source may be disposed at positions spaced apart from each other.

According to embodiments of the present invention, light sources with different wavelengths are irradiated to the same shooting point using a single defect detection device, and images for the irradiated light sources are acquired and processed respectively, thereby providing information on the surface of the object. Reliability in detecting defects can be increased.

In addition, since the existing total reflection mirror, concave mirror, and retroreflector are not used, scattered or transmitted light can be removed, which has the effect of improving the performance of the defect detection device and reducing manufacturing costs.

1 is a diagram showing an example of a defect detection device.
Figure 2 is a diagram showing a lighting unit for an example of a defect detection device.
Figure 3 is a diagram showing another example of a defect detection device.
Figure 4 is a diagram showing another example of a defect detection device.
Figure 5 is a diagram for explaining an optical path for another example of a defect detection device.
Figure 6 is a diagram showing another example of a defect detection device.
Figure 7 is a diagram schematically showing a defect detection device according to a first embodiment of the present invention.
Figure 8 is a diagram for explaining the optical camera of the defect detection device according to the first embodiment of the present invention.
Figure 9 is a diagram schematically showing a defect detection device according to a second embodiment of the present invention.
Figure 10 is a diagram schematically showing a defect detection device according to a third embodiment of the present invention.
Figure 11 is a diagram showing a first example of an illuminator used in a defect detection device according to an embodiment of the present invention.
Figure 12 is a diagram showing a second example of an illuminator used in a defect detection device according to an embodiment of the present invention.
Figure 13 is a diagram showing a third example of an illuminator used in a defect detection device according to an embodiment of the present invention.
Figure 14 is a diagram showing a fourth example of an illuminator used in a defect detection device according to an embodiment of the present invention.
Figure 15 is a diagram showing a fifth example of an illuminator used in a defect detection device according to an embodiment of the present invention.
Figure 16 is a diagram showing a sixth example of an illuminator used in a defect detection device according to an embodiment of the present invention.
Figure 17 is a diagram showing a seventh example of an illuminator used in a defect detection device according to an embodiment of the present invention.

Hereinafter, specific embodiments for implementing the present invention will be described in detail with reference to the drawings.

In addition, when describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description will be omitted.

In addition, when a component is mentioned as being 'connected', 'supported', 'connected', 'supplied', 'delivered', or 'contacted' with another component, it is directly connected, supported, connected, or connected to that other component. It may be supplied, delivered, or contacted, but it should be understood that other components may exist in the middle.

The terms used in this specification are merely used to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise.

In addition, it should be noted in advance that expressions such as upper, lower, and side in this specification are explained based on the drawings, and may be expressed differently if the direction of the object in question changes. For the same reason, in the accompanying drawings, some components are exaggerated, omitted, or schematically shown, and the size of each component does not entirely reflect the actual size.

Additionally, terms including ordinal numbers, such as first, second, etc., may be used to describe various components, but the components are not limited by these terms. These terms are used only to distinguish one component from another.

As used in the specification, the meaning of "comprising" is to specify a specific characteristic, area, integer, step, operation, element and/or component, and to specify another specific property, area, integer, step, operation, element, component and/or group. It does not exclude the existence or addition of .

1 to 17, the defect detection device 10 according to the present invention will be described. The defect detection device 10 detects defects occurring on the surface of an object OT having reflective characteristics. The defect detection device 10 for this purpose irradiates light to the object (OT) using a light source, photographs the light reflected from the object (OT), and analyzes the captured image to detect defects on the surface of the object (OT). Detect if there is.

Referring to FIG. 1, light is irradiated to the object OT using the first lighting unit LA1 and the second lighting unit LA2, respectively, and is reflected back in the first retroreflecting plate RR1 and the second retroreflecting plate RR2. It is reflected and re-entered into the first lighting unit (LA1) and the second lighting unit (LA2). And the light reflected again from the first lighting unit (LA1) and the second lighting unit (LA2) is irradiated to the object (OT), reflected, and then incident on the first camera unit (CA1).

Accordingly, the first camera unit CA1 captures the light reflected from the first lighting unit LA1 and the second lighting unit LA2 as an image. At this time, the first lighting unit LA1 irradiates green light to the object OT, and the second lighting unit LA2 radiates red light to the object OT.

The image captured by the first camera unit CA1 can be supplemented using light indirectly emitted by the first retroreflector RR1 and the second retroreflector RR2.

At this time, the first lighting unit (LA1) and the second lighting unit (LA2) have a structure as shown in FIG. 2 to reflect back the light reflected from the first retroreflector (RR1) and the second retroreflector (RR2). may have, and each may be an imaging illuminator 200.

That is, the first lighting unit (LA1) and the second lighting unit (LA2) include a light source for irradiating light and an image sensor (IS) for photographing light, respectively. In addition, the first lighting unit (LA1) and the second lighting unit (LA2) each have a light source unit (LS), a condenser lens (FL), a first lens (L1), a second lens (L2), a light blocking plate (BP), and a half light source (LS) therein. Includes mirror (HM).

The first lighting unit (LA1) and the second lighting unit (LA2) may be an optical camera 100 of the schlieren technique using the first retroreflective plate (RR1) and the second retroreflective plate (RR2), and the object (OT) The light reflected from can be incident on the image sensor (IS) through the half mirror (HM). In the first lighting unit LA1 and the second lighting unit LA2, light emitted from a light source of a single wavelength is incident on the internal image sensor IS.

Referring to FIG. 3, another example of the defect detection device 10 includes a first light source unit (LS1) and a second light source unit (LS2), a condenser lens (FL), a dichroic mirror (DM), and a first camera unit ( CA1), a second camera unit (CA2), and an image processor (IP).

The light irradiated from the first light source unit LS1 is reflected from the object OT and then enters the first camera unit CA1 through the condenser lens FL and the dichroic mirror DM, and is transmitted to the second light source unit ( The light irradiated from LS2) is reflected from the object OT and then enters the second camera unit CA2 through the condenser lens FL and the dichroic mirror DM. At this time, the light emitted from the first light source unit LS1 may not be reflected from the dichroic mirror DM, and the light emitted from the second light source unit LS2 may have the characteristic of being reflected from the dichroic mirror DM. there is.

Therefore, the image processor (IP) can detect whether there is a defect in the object (OT) by processing the images acquired from the first camera and the second camera.

That is, the defect detection device 10 shown in FIG. 3 uses two light sources and two cameras.

Referring to FIG. 4, as another example of a defect detection device, light incident on the first camera unit (CA1) includes an object (OT), a first dichroic mirror (DM1), and a second dichroic mirror (DM2). ), is incident through the first retroreflector (RR1) and the second retroreflector (RR2).

At this time, referring to FIG. 5, looking at the movement path of light, ① the light irradiated from the first light source unit LS1 is ② reflected from the object OT, and ③ is reflected from the second dichroic mirror DM2. And, it is reflected from ④ the second retroreflector (RR2) and then again from ⑤ the second dichroic mirror (DM2). And ⑥ it is reflected again from the object (OT) and enters the first camera unit (CA1). At this time, the light emitted from the first light source unit LS1 is transmitted as is without being reflected by the first dichroic mirror DM1.

Additionally, the light emitted from the second light source unit LS2 is reflected from the object OT symmetrically with the light emitted from the first light source unit LS1 and is reflected from the first dichroic mirror DM1. Then, it is reflected from the first retroreflector (RR1) and then reflected again from the first dichroic mirror (DM1). Then, it is reflected again from the object OT and enters the first camera unit CA1. At this time, the light emitted from the second light source unit LS2 is transmitted as is without being reflected by the second dichroic mirror DM2.

Therefore, the light irradiated from the first light source unit (LS1) and the second light source unit (LS2) is transmitted through the first dichroic mirror (DM1), the second dichroic mirror (DM2), the first retroreflector (RR1), and the second retroreflector. Loss occurs while passing through the reflector RR2, and due to the complex structure, uniformity of illumination may be reduced. Therefore, the image obtained from the first camera unit CA1 has limitations in image quality.

Referring to FIG. 6, as another example of the defect detection device 10, the light emitted from the light source unit LS, which irradiates light of a single wavelength, is reflected by the half mirror HM and is irradiated to the object OT. You can. And the light reflected from the object (OT) may be incident on the image sensor (IS). At this time, the light blocking plate (BP) can be adjusted in the X-Y direction. This defect detection device 10 uses light of a single wavelength, and as a half mirror (HM) is used, light loss may occur.

Referring to FIG. 7, the defect detection device 10 according to an embodiment of the present invention includes an optical camera 100, an illuminator 200, and a controller 300.

As shown in FIG. 8, the optical camera 100 does not have a total reflection mirror, a half mirror (HM), a concave mirror for reflection, a retroreflector, or a polarizing filter installed inside. The optical camera 100 includes a first lens (L1), a second lens (L2), a light blocking plate (BP), and an image sensor (IS).

The first lens (L1) and the second lens (L2) are provided to collect incident light. The first lens (L1) and the second lens (L2) may include one or more of a convex lens, a concave lens, and an aspherical lens.

The light blocking plate (BP) serves to block unnecessary light. The light blocking plate (BP) can cut off a certain amount of light.

The image sensor (IS) receives light that has passed through the first lens (L1), the second lens (L2), and the light blocking plate (BP), and converts the image generated through the input light into an electrical signal and outputs it.

This optical camera 100 uses the direct irradiation schlieren technique.

The illuminator 200 includes two or more light source units therein. That is, the illuminator 200 includes a first light source unit LS1 and a second light source unit LS2, and the wavelength of light emitted from the first light source unit LS1 and the wavelength of light emitted from the second light source unit LS2 may be different.

Additionally, the illuminator 200 may irradiate light sequentially to the object OT instead of emitting light from the first light source unit LS1 and the second light source unit LS2 simultaneously.

Accordingly, the light emitted from the first light source unit LS1 and the second light source unit LS2 may have different reflection characteristics on the object OT depending on the wavelength. Accordingly, the characteristics of the light incident on the optical camera 100 may be different between the light emitted from the first light source unit LS1 and the light emitted from the second light source unit LS2. For example, the amount of light emitted from the first light source unit LS1 reflected from the object OT may be different from the amount of light emitted from the second light source unit LS2 reflected from the object OT. .

The light irradiated from the first light source unit LS1 and the second light source unit LS2 may be sequentially irradiated to the same position of the object OT, and the light reflected from the same position of the object OT may be transmitted to the optical camera 100. ) can be hired sequentially.

The controller 300 is electrically connected to the optical camera 100 and processes two images with different characteristics captured by the optical camera 100. At this time, when processing two images with different characteristics, the controller 300 can improve discrimination of the images by comparing them with each other, and can also minimize errors between true and false components. Here, the two images with different characteristics are the light irradiated from the first light source unit LS1 and reflected from the object OT and the light irradiated from the second light source unit LS2 and reflected from the object OT using the optical camera 100. ) is an image generated by incident light.

This controller 300 can control the illuminator 200 so that light is emitted from the first light source unit LS1 and the second light source unit LS2, respectively. That is, the controller 300 can control the first light source unit LS1 and the second light source unit LS2 to sequentially emit light. This controller 300 may be implemented by an arithmetic device including a microprocessor, a memory, etc., and since the implementation method is obvious to those skilled in the art, further detailed description will be omitted.

Referring to FIG. 9, the defect detection device 10 according to the second embodiment of the present invention includes an optical camera 100, a light source unit LS, and a controller 300. While explaining the defect detection device 10 according to this embodiment, the same description as in the first embodiment will be omitted.

The light source unit LS may integrate two light sources capable of irradiating light of different wavelengths. Additionally, the light source unit LS can be controlled by the controller 300 to emit light from each of the two light sources.

Therefore, the light irradiated from the light source unit LS may be reflected from the object OT and enter the optical camera 100.

Referring to FIG. 10, the defect detection device 10 according to the third embodiment of the present invention includes an optical camera 100, a first light source unit LS1, a second light source unit LS2, and a controller 300. . While explaining the defect detection device 10 according to this embodiment, the same description as in the first embodiment will be omitted.

The first light source unit LS1 and the second light source unit LS2 may be disposed at different positions and may irradiate light to the object OT from different positions. At this time, the first light source unit LS1 and the second light source unit LS2 may be placed in a position where the light irradiated to the object OT is irradiated at the same angle from the horizontal plane, but this is not limited to this, regardless of the angle irradiated. It is sufficient that light reflected from the object OT can be incident on the optical camera 100.

Referring to FIG. 11, as a first example of the illuminator 200, the first light source unit LS1 may have a plurality of first lamps LP1 disposed therein, and the plurality of first lamps LP1 may be the same as each other. Can emit waves. At this time, the first lamps LP1 may be arranged to be spaced a predetermined distance apart from each other. Accordingly, the amount of light emitted from the first light source unit LS1 may be greater than when one first lamp LP1 is disposed. Additionally, the number of first lamps LP1 included in the first light source unit LS1 may vary as needed.

Referring to FIG. 12, as a second example of the illuminator 200, one first lamp (LP1) may be disposed inside the first light source unit (LS1), and one first lamp (LP1) is shown as shown in FIG. As described above, it may have a predetermined length. Light emitted from the first lamp LP1 having a predetermined length may be emitted in an approximately rectangular shape, like the shape of the first lamp LP1.

Additionally, light can be condensed using a cylindrical lens to correspond to the first lamp LP1 having a predetermined length.

Referring to FIG. 13, as a third example of the illuminator 200, the second light source unit LS2 may have a plurality of second lamps LP2 disposed therein, and the plurality of second lamps LP2 may be identical to each other. Can emit waves. At this time, the second lamps LP2 may be arranged to be spaced a predetermined distance apart from each other. Accordingly, the amount of light emitted from the second light source unit LS2 may be greater than when one second lamp LP2 is disposed. Additionally, the number of second lamps LP2 included in the second light source unit LS2 may vary as needed.

Here, the light emitted from the second lamp LP2 included in the second light source unit LS2 shown in FIG. 13 is the light emitted from the first lamp LP1 included in the first light source unit LS1 shown in FIG. 11. It may be light of a different wavelength than light.

Referring to FIG. 14, as a fourth example of the illuminator 200, one second lamp (LP2) may be disposed inside the second light source unit (LS2), and one second lamp (LP2) is shown. As described above, it may have a predetermined length. Light emitted from the second lamp LP2 having a predetermined length may be emitted in an approximately rectangular shape, like the shape of the second lamp LP2.

Additionally, light can be condensed using a cylindrical lens to correspond to the second lamp LP2 having a predetermined length.

As described above, the first light source unit LS1 and the second light source unit LS2 shown in FIGS. 11 to 14 can be applied to the defect defect device according to the third embodiment shown in FIG. 10.

Referring to FIG. 15 , as a fifth example of the illuminator 200, the light source unit LS may include a plurality of first lamps LP1 and a plurality of second lamps LP2. A plurality of first lamps LP1 may be disposed on one substrate at predetermined intervals, and a plurality of second lamps LP2 may be disposed on one substrate at predetermined intervals.

At this time, the plurality of first lamps (LP1) and the plurality of second lamps (LP2) may have the same number, but are not limited to this, and the area or reflection characteristics of the surface of the object (OT) may be adjusted as necessary. For this reason, they can have different numbers.

Referring to FIG. 16 , as a sixth example of the illuminator 200, the light source unit LS may include one first lamp LP1 and one second lamp LP2. The first lamp LP1 and the second lamp LP2 may each have a predetermined length. The light emitted from the first lamp (LP1) and the second lamp (LP2) having a predetermined length may be emitted in an approximately rectangular shape, like the shapes of the first lamp (LP1) and the second lamp (LP2), respectively. .

Additionally, light can be condensed using a cylindrical lens to correspond to the first lamp (LP1) and the second lamp (LP2) having a predetermined length. Additionally, the number of first lamps LP1 and second lamps LP2 may vary depending on the surface area and reflection characteristics of the object OT.

Referring to FIG. 17 , as a seventh example of the illuminator 200, the light source unit LS may include a plurality of first lamps LP1 and a plurality of second lamps LP2 disposed on one substrate. The plurality of first lamps LP1 and the plurality of second lamps LP2 may be arranged to alternate with each other.

The light source unit LS shown in FIGS. 14 to 17 may be used as the illuminator 200 or the light source unit LS of the defect detection device 10 described in the first and second embodiments of the present invention.

Although embodiments of the present invention have been described above as specific embodiments, this is merely an example, and the present invention is not limited thereto, and should be construed as having the widest scope according to the embodiments disclosed herein. A person skilled in the art may implement a pattern of a shape not specified by combining/substituting the disclosed embodiments, but this also does not depart from the scope of the present invention. In addition, a person skilled in the art can easily change or modify the embodiments disclosed based on the present specification, and it is clear that such changes or modifications also fall within the scope of the present invention.

10: Defect detection device
100: optical camera 200: illuminator
300: controller
LA1: 1st lighting section LA2: 2nd lighting section
LS: light source
LS1: first light source LP1: first lamp
LS2: Second light source LP2: Second lamp
FL: condenser lens
L1: 1st lens L2: 2nd lens
BP: light shield
RR1: 1st retroreflector RR2: 2nd retroreflector
HM: Half mirror
DM: dichroic mirror
DM1: First dichroic mirror DM2: Second dichroic mirror
IS: Image sensor
CA1: First camera unit CA2: Second camera unit
OT: Object IP: Image processor

Claims (3)

a first lighting unit including a first light source unit that irradiates light with a predetermined wavelength to an object;
a second lighting unit including a second light source unit that radiates light having a different wavelength from that of the first light source unit to the object;
The light irradiated to the object is reflected from any one of the first light source unit and the second light source unit and then becomes incident, and the incident light is again incident on one of the first light source unit and the second light source unit. A retroreflector that reflects back to the object;
an optical camera that photographs the light emitted from the first light source unit and the second light source unit via the retroreflector and is reflected on the object to detect defects; and
It includes a controller that processes images captured by the optical camera to detect defects on the surface of the object,
The retroreflector is,
A first retroreflector that reflects the light irradiated to the object from the first lighting unit and then enters the object, and reflects the incident light so that it is incident again to the first lighting unit, and the light irradiated to the object from the second lighting unit is reflected. and a second retroreflector that is incident and reflects the incident light so that it is incident again on the second lighting unit,
The first lighting unit,
a first condenser lens that condenses the light emitted from the first light source unit;
a first lighting unit lens through which light reflected from the first retroreflector is transmitted;
a second lighting unit lens through which the light collected by the first condenser lens is transmitted in one direction and the light reflected and incident from the first retroreflector is transmitted in the other direction;
A first half mirror disposed between the first lighting unit lens and the second lighting unit lens to reflect the light collected by the first condenser lens and irradiate it to the object, and to transmit the light reflected from the first retroreflector. ; and
It further includes a first lighting unit image sensor that photographs light transmitted through the first lighting unit lens and the second lighting unit lens,
The second lighting unit,
a second condenser lens that condenses the light emitted from the second light source;
a third illumination unit lens through which light reflected from the second retroreflector is transmitted;
a fourth lighting unit lens through which the light collected by the second condenser lens is transmitted in one direction and the light reflected and incident from the second retroreflector is transmitted in the other direction;
A second half mirror disposed between the third lighting unit lens and the fourth lighting unit lens to reflect light collected by the second condenser lens to irradiate the object and transmit the light reflected from the second retroreflector. ; and
It further includes a second lighting unit image sensor that photographs light transmitted through the third lighting unit lens and the fourth lighting unit lens,
The angle of light traveling between the first lighting unit and the first retroreflecting plate by reflecting from the object is smaller than the angle of light traveling between the second lighting unit and the second retroreflecting plate by reflecting from the object,
Defect detection device. According to claim 1,
The controller controls the first light source unit and the second light source unit to adjust the time difference in which light is irradiated from the first light source unit and the second light source unit, respectively.
Defect detection device. According to claim 1,
The optical camera is,
a first lens that focuses light reflected from each of the objects;
a second lens that condenses the light transmitted through the first lens;
a light blocking plate disposed between the first lens and the second lens and blocking a portion of light passing through the first lens; and
Comprising an image sensor that receives light passing through the second lens and outputs an electrical image signal from the incident light,
Defect detection device.

Images