TWI498546B - Defect inspection device and defect inspection method - Google Patents

Description

Defect inspection device and defect inspection method

The present invention relates to an apparatus and method for inspecting an inner layer defect of an object to be inspected.

A technique for detecting a defect by irradiating light to a sheet-like article and performing image processing based on an image obtained by receiving a transmitted light or reflected light by a camera is known. Here, in the case where the object to be inspected is a polarizing film (optical film) used in a liquid crystal display or the like, it is desirable to discriminate that the defect exists on the surface or exists in the inner layer. This is because the polarizing film or the like is inspected in a state in which the surface is adhered to the protective sheet, because the protective sheet is peeled off at the end, so that even if the surface has defects, it is not a problem.

Patent Document 1 describes that a surface layer and an inner layer are shifted from a focus position, and then a surface defect and an inner layer defect are distinguished based on the plurality of images. However, it is necessary to perform a plurality of photographs at the surface position and the inner layer position, and it has a problem that the inspection takes time. Also, it is necessary to focus on the mechanism at each position, resulting in an increase in cost. Further, since the focus position is determined at the focus position, the accuracy of the focus position is important. Therefore, it is necessary to suppress the positional variation of the inspection object, thereby increasing the cost of the table for suppressing the positional change, and it is necessary to make the inspection object stationary in order to suppress the positional fluctuation. This causes the inspection cycle to become longer.

Patent Document 2 describes: according to illumination under coaxial illumination The image taken and the image taken under the illumination of the diffuse illumination distinguish the surface defect from the inner layer defect. However, since it is necessary to slide the illumination system and shoot twice, there is a problem that the inspection takes time. There is also a need for a mechanism that slides the illumination, resulting in an increase in cost. Moreover, since a large member such as illumination is to be driven, the drive unit needs to be repaired.

Leading patent literature Patent literature

Patent Document 1 Japanese Patent Laid-Open Publication No. 2005-98970

Patent Document 2 Japanese Patent Laid-Open Publication No. 2001-108639

The present invention has been made in view of the above problems, and an object thereof is to perform inspection for discriminating surface defects and inner layer defects at low cost and at high speed.

In order to solve the above problems, a defect inspection device according to an aspect of the present invention is a defect inspection device for inspecting a defect of a sheet-like object to be inspected, the device comprising: a first irradiation means for irradiating the object to be inspected with the first light; The second illuminating means irradiates the object with the second light; and the photographic means obtains photographic data corresponding to the intensity of the reflected light of the first light and the transmitted light of the second light; and the detecting means is based on Detecting the inner layer defects of the object to be inspected by the intensity of the reflected light and the transmitted light at the same position of the object to be inspected by the photographing means; The photographing means and the second irradiation means are disposed such that the second light is transmitted between the photographing means.

That is, the positional relationship between the second irradiation means and the photographing means is It is preferable that the positive transmitted light which is the light irradiated from the second irradiation means is not incident on the photographing means, and the indirect transmitted light is incident on the photographing means. The indirect transmitted light refers to transmitted light that deviates from the positive transmission direction by reflection or scattering of defects existing in the object to be inspected. Thereby, dark field photography of defects can be realized, and the dynamic range is improved. In this case, it is detected that the transmitted light passing through the inner layer defect is stronger than the transmitted light through the transmitted surface defect.

By adopting the composition as described above, it is possible to respond to reflection Photographic data of light intensity and photographic data in response to indirect transmitted light intensity are used to discriminate internal defects. That is, it is known that there is a certain defect in the portion where the reflected light or the indirectly transmitted light intensity is detected, and if the indirect transmitted light intensity is larger than the reflected light intensity for the same defect, the defect inner layer defect can be discriminated.

As mentioned above, the second light is transmitted between the second light. In other words, it is preferable to shorten the wavelength of the second light. The shorter the wavelength, the greater the scattering effect of the defect, and therefore the transmitted light intensity of the transmitted defect increases. Further, the shorter the wavelength of the second light system, the larger the scattering effect, but it is preferable to use blue light (near the wavelength of 450 nm) in consideration of the ease of obtaining the light source and the light receiving element.

Another aspect of the defect inspection device of the present invention is an inspection A defect inspection device for a defect of a sheet-like object to be inspected, the device comprising: a first irradiation means for irradiating the object with the first light; The illuminating means irradiates the object with the second light; and the photographic means obtains photographic data corresponding to the intensity of the reflected light of the first light and the transmitted light of the second light; and the detecting means The intensity of the reflected light and the transmitted light at the same position of the object to be inspected by the photographing means detects the inner layer defect of the object to be inspected; and the photographing means can capture the positive transmitted light of the second light Disposing the imaging means and the second irradiation means; and providing polarization polarization orthogonal to each other between the second irradiation means and the inspection object and between the imaging means and the second irradiation means Device.

In this way, the position of the second illumination means and the photographing means The relationship is also preferably a positive transmission light incident imaging means for producing light irradiated from the second irradiation means. In other words, it is also possible to form a configuration in which the transmitted light that does not scatter in the object to be inspected and that advances linearly can be imaged. In this case, the polarizing filters whose transmission axes are orthogonal to each other are provided between the second irradiation means and the inspection object, and between the imaging means and the inspection object. The light passing through the defect-free portion in the object to be inspected is blocked by the polarizing filter. In contrast, since the light passing through the defective portion is scattered in the polarized light when passing through the defective portion, it passes through the polarizing filter and is incident. Means of photography. According to this configuration, dark field photography of defects can also be realized. It is also detected that the positive transmitted light that has passed through the inner layer defect is stronger than the positive transmitted light that has passed through the surface defect.

By adopting the composition as described above, it can be based on The photographic data of the reflected light intensity of the first irradiation means and the photographic data corresponding to the intensity of the positive transmitted light are detected. That is, it is known that there is a certain defect in the portion where the reflected light or the transmitted light intensity is detected, For the same defect, if the intensity of the specular reflected light is greater than the intensity of the reflected light, the defect of the inner layer of the defect can be discriminated.

In addition, the defects include foreign matter, pores, wrinkles, mottles, mites, and the like. The surface defect is a defect existing in the vicinity of the surface of the test object, and in the case where the test object has a multilayer structure, it is a defect existing in the outermost layer. The inner layer defect is a defect existing inside the test object, and when the test object has a multilayer structure, it is a defect existing outside the outermost layer. However, it is not necessary for the object to be inspected to have a multilayer structure. In the case where the object to be inspected does not have a multi-layered structure, the defect located within a predetermined distance from the surface belongs to the surface defect, and the defect located further inside is the inner layer defect.

In the present invention, it is possible to increase the speed of the inspection by simultaneously measuring the configuration of the reflected light reflected by the first light in the test object and the transmitted light after the second light is transmitted through the test object. In order to measure at the same time, there are two methods of using a camera and a method of using one camera. In the case of simultaneously measuring with two cameras, it is preferable to set the irradiation position of the first light and the irradiation position of the second light to different positions. In this case, it is necessary to provide means for aligning the positional alignment of the photographic material of the reflected light with the photographic material of the transmitted light at the defect inspection device. When the reflected light and the transmitted light are simultaneously measured using one camera, the colors (wavelengths) of the first light and the second light are different, and it is preferable to take a color camera. Since it is not necessary to move the irradiation means or the like in either case, high-speed inspection can be performed, and the configuration of the apparatus can be simplified, and the manufacturing cost or the maintenance cost can be suppressed.

In the case of using one camera as a means of photography, The first irradiation means irradiates light from one side of the inspection object, and the second irradiation means irradiates light from the other side of the inspection object, and the photographing means takes the reflected light of the first light and the second light from the side. Through the light. On the other hand, in the case where two cameras are used as the photographing means, the first photographing means for irradiating light from the same side of the object to be inspected by the first and second irradiation means, and for taking the reflected light of the first light, And the second imaging means for capturing the transmitted light of the second light (indirect transmitted light or positive transmitted light) is disposed on a different side of the object to be inspected. However, even in the case of using two cameras, the first and second irradiation means may be disposed on different sides, and the first and second imaging means may be disposed on the same side.

Irradiation position and borrowing of the first light by the first irradiation means The irradiation position of the second light of the two irradiation means may be the same or different.

In the case of different irradiation positions, as long as the use of shooting each Just 2 cameras in the irradiation position. In this case, a positioning means for aligning the image data of the reflected light of the first light with the position of the image data of the transmitted light of the second light is provided, and the two photographic materials after the alignment are arranged. , detection of inner defects.

On the other hand, the irradiation position of the first light and the second light When the same is true, the color (wavelength) of each light is different. For example, any one of light can be selected from red light (near wavelength 650 nm), green light (near wavelength 550 nm), and blue light (near wavelength 450 nm). Here, in the case where the configuration of the transmitted light from the second irradiation means is taken, the second irradiation means is preferably blue light as described above, and therefore the first irradiation means may be red light or green light. In addition, the first light and the second light The irradiation means may be the same. The photographing means may be a color camera having a plurality of linear light receiving elements that receive the respective lights. Further, the photographing means may be a color camera having a spectroscopic element that splits the incident light and a plurality of light receiving elements that respectively obtain the light intensity after the splitting. Further, in the case where a plurality of linear light-receiving elements are used, since the photographing positions are different, it is necessary to perform alignment, and relatively, after receiving light, the light is received. Since the photographing positions are identical, it is not necessary to perform alignment.

Furthermore, the invention is understood to have at least the means Part of the defect inspection device. Furthermore, the invention is also to be understood as a defect inspection method having at least a portion of the process, or a program for implementing the method. This means and the processing of each possible combination of each other may constitute the invention.

A defect inspection method which is one embodiment of the present invention is a A defect inspection method for inspecting defects of a sheet-like test object, the method comprising: an irradiation step of irradiating the first light and the second light to the test object; and a photographing step of obtaining a reflection corresponding to the first light The photographic data of the intensity of the light and the transmitted light of the second light; and the detecting step of detecting the intensity of the reflected light and the transmitted light at the same position of the object to be inspected by the photographing step The inner layer defect of the object to be inspected; in the photographing step, the second light is photographed to transmit the transmitted light.

A defect inspection method which is one embodiment of the present invention is a A defect inspection method for inspecting defects of a sheet-like test object, the method comprising: an irradiation step of irradiating the first light and the second light to the test object; and a photographing step of obtaining a reflection corresponding to the first light Light and the first The photographic data of the intensity of the transmitted light of the light; and the detecting step of detecting the detected object based on the intensity of the reflected light and the transmitted light at the same position of the object to be inspected at the photographing step An inner layer defect; in the photographing step, the second light is transmitted through the first light, and the second light is irradiated to the object to be inspected through the first polarizing filter and transmitted through the object to be inspected The image is captured by a second polarizing filter that is orthogonal to the first polarizing filter via the transmission axis.

According to the present invention, it is possible to perform defect inspection for distinguishing between surface defects and inner layer defects at high speed and at low cost.

S‧‧‧Inspected objects

101‧‧‧Light source (first light source)

102‧‧‧Light source (2nd light source)

201‧‧‧ camera

202‧‧‧ camera

300‧‧‧Signal Processing Unit

301‧‧‧Reflex Optical System Signal Processing Department

302‧‧‧Transmission through the optical system signal processing department

303‧‧‧ Position Alignment Processing Department

304‧‧‧Defect Detection Department

305‧‧‧Comparative Decision Department

306‧‧‧Output Department

401‧‧‧ polarizing filter

402‧‧‧Polarizing filter

Fig. 1 is a view showing an overall outline of a defect inspection system.

Fig. 2 is a view showing the configuration of a defect inspection device according to the first embodiment.

Fig. 3 is a view for explaining reflected light (a) and indirect transmitted light (b) of surface defects and inner layer defects in the first embodiment.

Fig. 4 is a view for explaining the luminance ratio of the reflected light (b) and the indirect transmitted light (c) which are present in the defect (a) of the test object and in the case where the test object is imaged.

Fig. 5 is a flow chart showing the flow of the defect inspection method of the first embodiment.

Fig. 6 is a view showing the configuration of a defect inspection device according to a second embodiment.

Fig. 7 is a view for explaining transmitted light passing through surface defects and inner layer defects in the second embodiment.

Fig. 8 is a view showing the configuration of a defect inspection device according to a third embodiment.

Fig. 9 is a view showing the configuration of a defect inspection device according to a fourth embodiment.

Fig. 10 is a view showing the configuration of an optical system of a defect inspection device according to a modification of the third and fourth embodiments.

Fig. 11 is a view for explaining a defect inspection method according to a fifth embodiment.

Fig. 12 is a view showing the configuration of an optical system of a defect inspection device according to a modification of the first and second embodiments.

Hereinafter, embodiments of the present invention will be described in detail by way of examples with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the constituent elements described in the examples are not intended to limit the scope of the present invention unless otherwise specified.

Fig. 1 shows a schematic configuration of the entire defect inspection system of the present invention. The defect inspection system is a system that inspects the sheet-like object S to be conveyed by the conveyance roller 400. The test object S is, for example, a polarizing film for a liquid crystal display. In the inspection stage, the polarizing film has a multilayer structure in which a sheet-like polarizing element is provided with a protective sheet. In the defect inspection system of the present embodiment, an appropriate defect inspection is performed, and the defect inspection is performed to detect a defect existing in the inner layer (polarizing element layer) of the inspection object S, thereby avoiding erroneous observation (false detection of defects). Proper defect detection.

In the defect inspection system of the present embodiment, two light sources 101 and 102 that irradiate the object S with light are provided. The light source 101 irradiates the inspection object S with light from the same side as the camera 200. Light source 102 is from The object S is irradiated with light on the opposite side of the camera 200. The camera 200 captures the reflected light on the surface of the object to be inspected by the light emitted from the light source 101, and the transmitted light that is irradiated from the light source 102 and transmitted through the object to be inspected. Further, although only one camera 200 is illustrated, two cameras that respectively detect reflected light and transmitted light may be used. The photographic data taken by the camera 200 is sent to the signal processing unit 300, and the defect in the object S is detected. At this time, the signal processing unit 300 determines whether the detected defect exists in the inner layer of the test object S or exists on the surface based on the intensity of the reflected light and the transmitted light.

Here, the outline of the defect inspection system is briefly explained. Hereinafter, each embodiment will be described in detail.

<First embodiment>

Fig. 2 is a view showing the configuration of a defect inspection device according to the first embodiment. The defect inspection device is composed of the light sources 101, 102, the cameras 201, 202, and the signal processing unit 300.

The light source 101 irradiates the object S with the light 101a from the same side as the camera 201. The wavelength of the light 101a irradiated by the light source 101 is not particularly limited, and may be visible light, ultraviolet light or infrared light. Further, the light 101a may not be light of a single wavelength. In the present embodiment, for example, green light is used as the light 101a. The light source 101 is disposed such that the light 101a can be obliquely irradiated onto the object S to be inspected. The camera 201 is a line sensor camera, whether it is a color camera or a black and white camera. The camera 201 is disposed in a direction orthogonal to the conveyance direction of the inspection object S, and is disposed so as to be capable of photographing the irradiation position of the light 101a from the vertical direction. The positional relationship between the light source 101 and the camera 201 is such that the regular reflected light of the light 101a does not enter and expands. The positional relationship in which the scattered reflected light 101b is incident on the camera 201 is preferable. Thereby, it is possible to perform dark-field photography on the defect of the object S to be inspected, and it is possible to take a defect with high contrast. Further, the positional relationship between the light source 101 and the camera 201 may be any configuration as long as it is capable of realizing dark field photography. The light source 101 and the camera 201 are referred to as reflective optical systems in this patent specification.

The light source 102 is from the opposite side of the camera 202 to the object to be inspected S illuminates light 102a. The wavelength of the light 102a irradiated by the light source 102 may be arbitrary as in the case of the light source 101. However, in the present embodiment, it is preferable to use blue light. The reason for the better Blu-ray will be described later. The light source 102 is arranged such that the light 102a can be obliquely irradiated onto the object S to be inspected. In the present embodiment, the irradiation positions of the light 101a and the light 102a are shifted in the conveyance direction. The camera 202 is a line sensor camera, whether it is a color camera or a black and white camera. The camera 202 is disposed in a direction orthogonal to the conveyance direction of the inspection object S, and is disposed so as to be capable of photographing the irradiation position of the light 102a from the vertical direction. The positional relationship between the light source 102 and the camera 202 is preferably such that the positive transmitted light of the light 102a is not incident and the indirect transmitted light 102b is incident on the camera 202. Thereby, dark-field photography can be performed on the defects of the object S to be inspected, and defects can be photographed with high contrast. Further, the positional relationship between the light source 102 and the camera 202 may be any configuration as long as it is capable of realizing dark field photography. Light source 102 and camera 202 are referred to as indirect transmission optical systems in this patent specification.

The signal processing unit 300 includes a CPU (Central Processing Processing) Main memory device such as device), RAM (random access memory), auxiliary memory device such as HDD (hard disk) or SSD (solid state hard disk), mouse, keyboard, A computer such as an input/output device such as a display. The computer program of the computer executes the computer program, and functions as the reflection optical system signal processing unit 301, the transmission optical system signal processing unit 302, the alignment processing unit 303, the defect detection unit 304, the comparison determination unit 305, and the output unit 306. .

The reflection optical system signal processing unit 301 acquires the slave camera 201 photographic data output, and the brightness ratio is obtained from the photographic data. In the present embodiment, since the green light source is used as the light source 101, only the luminance ratio of the G signal is required when the camera 201 is a color camera. In addition, the luminance ratio is a value obtained by dividing the charge (photographic data) of each light-receiving element by the charge (photographic data) of each light-receiving element when the object to be inspected is not intended. In other words, the photographic data of the object S to be inspected without defects is obtained in advance, and the ratio of the photographic data at the time of the inspection to the value is set as the luminance ratio. The "charge of each light-receiving element in the case of no defect" can also be used as an average value of charges of the respective light-receiving elements at the time of performing plural imaging. The luminance ratio is a value close to 1 in the case of no defect, and in the case of a defect, the diffused reflected light is incident on the defect, and becomes a value larger than 1. In this patent specification, the luminance ratio calculated by the reflection optical system signal processing unit 301 is referred to as a reflected light luminance ratio.

The optical system signal processing unit 302 acquires the slave camera The photographic data outputted by 202 is obtained from the photographic data in the same manner as described above. In the present embodiment, since the blue light source is used as the light source 102, when the camera 202 is a color camera, only the luminance ratio of the B signal is required. The luminance ratio obtained here is also a value close to 1 in the case of no defect, and a value larger than 1 in the case of a defect. In this In the patent specification, the luminance ratio calculated by the optical system signal processing unit 302 is referred to as a transmitted light luminance ratio.

The position alignment processing unit 303 performs the brightness ratio of the reflected light The light is transmitted through the positional alignment of the data. Since the camera 201 is different from the photographing position of the camera 202, it takes time for the portion photographed by the camera 201 to reach the position to be photographed by the camera 202. In order to compare the luminance ratios of the same position obtained from the camera 201 and the camera 202, the alignment processing unit 303 performs the alignment processing based on the conveyance speed of the inspection object and the acquisition timing of the photograph data.

The defect detecting unit 304 is configured to reflect the brightness ratio of the reflected light. Defects were detected by various data of the brightness ratio data. The defect detecting unit 304 detects all the defects without distinguishing whether the defect is an inner layer defect or a surface defect. Specifically, the defect detecting unit 304 determines that a defect exists when the luminance ratio is equal to or greater than a predetermined threshold. This threshold is used as a detection parameter and can be set externally.

The comparison determination unit 305 detects the defect detection unit 304. The defect is determined as an inner layer defect or a surface defect based on the ratio of the reflected light luminance to the transmitted light luminance in the defective portion. The comparison determination unit 305 determines that the defect having the transmitted light luminance ratio greater than the reflected light luminance ratio is the inner layer defect, and the defect having the reflected light luminance ratio larger than the transmitted light luminance ratio as the surface defect.

Referring to Figures 3 and 4, the method according to the above is explained. Reasons for identifying inner defects and surface defects.

Fig. 3(a) is a view for explaining reflected light of the light 101a irradiated from the light source 101 in the defect. The light 101a irradiated from the light source 101 is diffused and reflected by the surface defect D _S and the inner layer defect D _I , and the diffused reflected light R _S , R _{I is} captured by the camera 201. Here, there is a feature that a strong diffusion reflection occurs on the surface defect, and a weak diffusion reflection occurs in the inner layer defect D _I . Accordingly, the surface defects detected intensity of the reflected light R _S D _S of the intensity stronger than the inner defect of the reflected light R D _{I I,.}

Fig. 3(b) is a view for explaining that the light 102a irradiated from the light source 102 transmits light between the defects. The light 102a irradiated from the light source 102 is scattered by the surface defect D _S and the inner layer defect D _I and deviates from the forward transmission direction. The indirect transmitted light T _S , T _{I is} captured by the camera 202. Here, there is a feature that the inner layer defect D _{I is} strongly scattered, and the surface defect D _S is relatively weakly scattered. Therefore, it is detected that the intensity of the transmitted light T _I between the inner layer defects D _I is stronger than the intensity of the transmitted light T _S between the surface defects D _S .

In addition, this scattering effect is based on the use of blue light in the light source 102. The reason for the source is better. The shorter the wavelength of the light 102a, the stronger the scattering effect of the inner layer defects, and therefore the stronger the transmitted light entering the camera 202. Therefore, the wavelength of the light irradiated from the light source 102 is preferably short. In consideration of the availability or cost of the light source or the light receiving element, it is preferable to use blue light from the light 102a irradiated from the light source 102.

Figure 4 illustrates the brightness ratio of inner and surface defects The map of the difference. Fig. 4(a) is a view showing the object to be inspected from the vertical direction, and shows that surface flaws (surface defects) 41 and inner layer foreign matter (inner layer defects) 42 are present at the photographing positions 43 of the cameras 201 and 202. Fig. 4(b) is a diagram showing the ratio of the reflected light luminance (the luminance ratio calculated by the reflection optical system signal processing unit 301) captured by the camera 201 at each pixel position. As described above, because the intensity of reflected light at the surface 瑕疵41 is higher than that of the inner layer of foreign matter 42 Since the intensity of the reflected light is larger, the luminance ratio at the position of the surface 瑕疵 41 is large, and the luminance ratio at the position of the inner layer foreign matter 42 is small. On the other hand, Fig. 4(c) is a diagram showing the ratio of the transmitted light luminance (the luminance ratio calculated by the transmission optical system signal processing unit 302) between the images captured by the camera 202 at each pixel position. As described above, since the transmitted light intensity between the inner layer foreign objects 42 is greater than the transmitted light intensity between the inner surface turns 41, the luminance ratio at the position of the inner layer foreign matter 42 is large, and at the position of the surface flaw 41. The brightness ratio is small.

Thus, the brightness ratio at the position of the inner layer foreign matter 42 is The over-light brightness ratio is larger than the reflected light brightness ratio. On the other hand, the brightness at the position of the surface 瑕疵41 is larger than the brightness ratio of the reflected light. Therefore, the comparison determination unit 305 can determine that the defect having the transmitted light luminance ratio larger than the reflected light luminance ratio is the inner layer defect.

In addition, in the description of Figures 3 and 4, In the case where the surface defect is a surface located on the front side (the side of the light source 101), the same phenomenon may be satisfied in the case where the surface on the back side has a defect. Further, even in the case where the inner layer defect and the surface defect exist at the same position, by appropriately adjusting the amount of light of the light source 102 or the threshold required for defect detection, it is possible to make a difference with respect to the detected defect, transmitted light. The ratio is greater than the brightness ratio of the reflected light. Therefore, even if the inner layer defect and the surface defect exist at the same position, the presence or absence of the inner layer defect can be determined based on the above principle.

The output unit 306 is in the case where a defect is detected, and the defect is Information on the location and the defect of the inner layer defect and the surface defect of the defect are output to the display device or the like, or the other device is transmitted material. Further, the output unit 306 may be configured to notify that there is a defect only when the inner layer defect exists.

Referring to the flowchart of FIG. 5, the use of this embodiment will be described. The defect inspection method of the defect inspection device. In step S51, the reflected light of the light irradiated from the light source 101 to the object S to be inspected is imaged by the camera 201, and the transmitted light of the light irradiated from the light source 102 to the object S to be inspected is captured by the camera 202. Further, the reflection optical system signal processing unit 301 and the transmission optical system signal processing unit 302 calculate the luminance ratios of the reflected light and the transmitted light. Since the object to be inspected S is transported, a two-dimensional distribution of luminance ratios can be obtained by photographing. In step S52, the alignment processing unit 303 performs a positional alignment process of the ratio of the reflected light luminance to the transmitted light luminance, thereby obtaining a ratio of the reflected light luminance ratio to the transmitted light luminance at the same position. In step S53, the defect detecting unit 304 detects a defect from the data of the ratio of the reflected light luminance at the same photographing position and the transmitted light luminance ratio. The defect detecting unit 304 determines that there is a defect in the portion when the luminance ratio is larger than the threshold value as the imaging parameter. Further, here, defect detection is performed after performing the alignment process, but the alignment process may be performed after the defect detection.

In step S54, the comparison determination section 305 detects the defect. The defect detected by the portion 304 determines whether the transmitted light luminance ratio is larger than the reflected light luminance ratio. When the transmitted light luminance ratio is large, the process proceeds to step S55, and the comparison determining unit 305 determines that the defect is an inner layer defect. On the other hand, when the reflected light luminance ratio is large, the process proceeds to step S56, and the comparison determining unit 305 determines that the defect is a surface defect. Then, in step S57, the output unit 306 outputs the position or the defect type for the detected defect. Classes, etc. However, it is also possible to output information about the defect only in the case where the defect is an inner layer defect, and not to output the data for the surface defect.

According to the defect inspection device of the embodiment, since At the same time, two kinds of reflected light and indirect transmitted light are photographed, so that high-speed inspection can be realized. Moreover, since the drive unit for moving the optical system is not required, the manufacturing cost or the maintenance cost can be suppressed. Further, by discriminating the defect based on the difference between the intensity of the reflected light and the intensity of the indirectly transmitted light, it is possible to achieve accurate discrimination. In particular, by using light of a short wavelength such as blue light having a high scattering effect in a defect as transmitted light, since the indirect transmitted light becomes stronger, the accuracy of the type discrimination is further improved.

<Second embodiment>

Fig. 6 shows the configuration of the defect inspection device of the second embodiment. The defect inspection apparatus of this embodiment is basically the same as that of the first embodiment, but the configuration of the optical system for transmitting light is different. In the first embodiment, the indirect transmitted light is captured, and in the present embodiment, the forward transmitted light is relatively photographed.

In the present embodiment, since the forward light is captured, the light source 102 and the camera 202 are arranged such that the irradiation direction of the light source 102 coincides with the imaging direction of the camera 202. For example, the light source 102 directly irradiates the inspection object S with light from below, and the camera 202 preferably images the inspection object S vertically from above.

In the present embodiment, in order to perform dark-field imaging, the polarizing filter 401 is disposed between the light source 102 and the inspection object S, and the polarizing filter 402 is disposed between the camera 202 and the inspection object S. Here, the polarizing filter 401 and the polarizing filter 402 are configured to transmit a shaft. Orthogonal to each other [nico-cross-nicol] configuration. Therefore, the light irradiated from the light source 102 is blocked by the polarizing filter 402 when the polarized light is not scattered in the object S, and does not reach the camera 202.

Fig. 7 is a view for explaining the transmitted light intensity in the case where the light irradiated from the light source 102 passes through the object S to be inspected. The transmitted light T ₀ passing through the defect-free portion is blocked by the polarizing filter 402 because the polarized light in the test object S does not scatter. On the other hand, the transmitted light T _I or T _S transmitted through the inner layer defect D _I or the surface defect D _S passes through the polarizing filter 402 because the polarized light is scattered when the defect is transmitted. Here, the scattering of the polarized light when the inner layer defect is transmitted is larger than the scattering of the polarized light when the surface defect is transmitted. Therefore, in the camera 202, it is detected that the intensity of the transmitted light T _I that has passed through the inner layer defect D _I is stronger than the transmitted light T _S that has passed through the surface defect D _S . Further, since the degree of scattering of the polarized light due to the defect does not depend on the wavelength of the light, the wavelength (color) of the light irradiated from the light source 102 may be arbitrary.

This embodiment is also the same as the first embodiment. The defect is determined to be an inner layer defect or a surface defect based on the intensity of the reflected light taken by the camera 201 and the transmitted light intensity captured by the camera 202. Since the configuration of the signal processing unit 300 is the same as that of the first embodiment, the description thereof is omitted.

The effect of the embodiment is the same as the effect of the first embodiment. same.

<Third embodiment>

In the first and second embodiments described above, two cameras are used for imaging. However, in the present embodiment, one camera is used for imaging.

Fig. 8 shows the defect inspection device of the embodiment. Composition. The configuration of Fig. 8 is modified according to the configuration of the first embodiment. As shown in Fig. 8, the defect inspection device is photographed by only one camera 200. Therefore, the irradiation position of the light source 101 and the irradiation position of the light source 102 are made the same, and the light emitted from the light source 101 is different from the wavelength (color) of the light irradiated from the light source 102. As described in the first embodiment, in the case of photographing indirect transmitted light, it is preferable to use a blue light source as the light source 102. Therefore, the light source 102 is a blue light source, and the light source 101 is a red light source or A green light source is all right.

Also shown in Fig. 8 is the detail of the camera 200 of the present embodiment. Department composition. The camera 200 includes a color camera that receives linear light receiving elements 200R, 200G, and 200B of light of different wavelengths. Each of the linear light receiving elements is disposed in a direction orthogonal to the conveyance direction of the inspection object S. In the eighth drawing, three light receiving elements that respectively receive light of R, G, and B are shown. However, it suffices to have two types of optical elements corresponding to the light source 101 and the light source 102.

Fig. 8 is a diagram showing a modified configuration according to the first embodiment. However, the second embodiment can be modified in the same manner. The configuration of this case is shown in Fig. 10. In this case as well, the light source 101 and the light source 102 illuminate the same position with light having different wavelengths, and are taken by one camera 200. Further, a polarizing filter 401 is provided between the light source 102 and the test object S, and a polarizing filter 402 is provided between the camera 200 and the test object S. Further, the configuration of the camera 200 or the light system emitted from the light source is the same as described above.

According to the defect inspection apparatus of the present embodiment, since the number of cameras can be set to one, space can be saved.

<Fourth embodiment>

This embodiment is a configuration that is imaged using one camera as in the third embodiment.

Fig. 9 shows the configuration of the defect inspection device of the present embodiment. The configuration of the ninth embodiment is the same as that of the third embodiment, and the configuration of the first embodiment is modified in the same manner as in the third embodiment, except that the configuration of the camera 200 is different. The camera 200 of the present embodiment includes the dichroic beamsplitters 211 and 212, and the R, G, and B target light receiving elements 210R, 210G, and 210B. In the configuration of Fig. 9, the dichroic beam splitter 211 reflects only blue light and transmits other light. The dichroic mirror 212 reflects only green light and transmits other light. The pair of red (R), green (G), and blue (B) beams split by the dichroic mirrors 211 and 212 are received by the light receiving elements 210R, 210G, and 210B, respectively.

In addition, although it is a structure which shows the light of the three colors of light, it is set as the structure which can isolate|separate the light of the light- Further, a dichroic beam splitter or a grating or the like may be employed as the spectroscopic element instead of the dichroic beam splitter.

In the ninth embodiment, the configuration is changed according to the first embodiment. However, the second embodiment can be modified in the same manner, and the configuration of the optical system shown in Fig. 10 can be employed.

According to the present embodiment, as in the third embodiment, since it can be imaged by one camera, there is an advantage that space can be saved. Furthermore, because the reflected light and the transmitted light are taken at exactly the same position, The signal processing unit 300 does not require the alignment processing unit 303. Further, since the positional deviation does not occur, even when the conveyance speed of the inspection object S changes, the defect detection with high accuracy without positional deviation can be performed.

<Fifth Embodiment>

The processing for detecting a defect in the signal processing unit 300 in this embodiment is different from the other embodiments, and the other components are the same. Specifically, the processing contents of the reflection optical system signal processing unit 301, the transmission optical system signal processing unit 302, the defect detection unit 304, and the comparison determination unit 305 are different.

In the first to fourth embodiments, the defect is detected based on whether or not the luminance ratio is larger than the threshold value. In the present embodiment, the defect is detected based on the histogram of the luminance ratio. When a histogram of a luminance ratio is calculated for a pixel of a line amount taken by a line camera, in the case where a defect exists, a portion other than the luminance ratio 1 (non-defective portion) also peaks. Therefore, defects can be detected based on the peaks appearing in the histogram.

The reflection optical system signal processing unit 301 and the transmission optical system signal processing unit 302 of the present embodiment calculate a luminance ratio histogram from the photographic data of the reflected light and the transmitted light. An example of the calculated histogram is shown in Fig. 11 .

Fig. 11 (a) and (b) are histograms obtained from photographing data of light irradiated from the light source 101. Fig. 11(a) is a histogram in the case of a surface defect, and Fig. 11(b) is a histogram in the case where an inner layer defect exists. Further, the peak of the luminance ratio 1 in Fig. 11 is omitted. As shown in Fig. 11, the width W of the peak is a case where the surface defect is wider than the case of the inner layer defect.

Fig. 11 (c) and (d) are histograms obtained from photographing data of light irradiated from the light source 102. Fig. 11(c) is a histogram in the case where there is a surface defect, and Fig. 11(d) is a histogram in the case where an inner layer defect exists. The width W of the peak of this case is wider for the case of the inner layer defect than for the surface defect.

In the defect detecting unit 304 of the present embodiment, when the width of the peak of the histogram obtained from the photographic data is equal to or greater than the predetermined threshold value, it is determined that the object S is defective. This threshold is used as a detection parameter and can be set externally.

The comparison determination unit 305 compares the width of the histogram of the reflected light and the width of the histogram of the transmitted light with respect to the defect detected by the defect detecting unit 304. As described above, if the width of the peak of the histogram of transmitted light is relatively wide, it can be judged that it is an inner layer defect, and if it is reversed, it can be judged to be a surface defect.

Further, in this case, defect detection and type discrimination are performed based on the width of the peak appearing in the histogram, but the defect can be detected in the same manner according to the area of the peak. In other words, the defect detecting unit 304 determines that there is a defect when there is a peak having an area equal to or greater than a predetermined threshold, and the comparison determining unit 305 determines that the area is large when the peak of the histogram of the transmitted light is large. Layer defects.

The defect detection and the type discrimination based on the histogram used in the present embodiment can be used instead of the defect detection and the type determination based on the luminance ratios in the first to fourth embodiments, but the two methods can be combined. By using both methods at the same time, it is possible to achieve better defect detection and type discrimination.

<Other>

In the above description, a polarizing film used as a test object in a liquid crystal display or the like is exemplified, but since it is only required to be processed according to the intensity of reflected light or the intensity of transmitted light, it is not based on the brightness ratio but on the brightness value itself. The same processing can be performed.

Further, in the above description, the detection of the defect or the determination of the type of the defect is performed based on the luminance ratio of the reflected light or the transmitted light. However, since the processing is performed based on the reflected light or the transmitted light intensity, the brightness value itself is not the brightness. The same can be done.

Further, the optical system configuration described above is merely an example, and various modifications can be made without departing from the scope of the technical idea of the present invention. For example, in the first and second embodiments in which two cameras are used, the respective objects are placed on the same side with respect to the object to be inspected, but this is not necessarily the case. Any configuration is acceptable as long as it can take both reflected and transmitted light. For example, as a modification of the first embodiment, as shown in Fig. 12(a), the light source 101 and the light source 102 may be disposed on the same side of the object S, and the camera 201 and the camera 202 may be placed in the same. Check the different sides of the object S. Similarly, as a modification of the second embodiment, a configuration as shown in Fig. 12(b) may be employed.

300‧‧‧Signal Processing Unit

301‧‧‧Reflex Optical System Signal Processing Department

302‧‧‧Transmission through the optical system signal processing department

303‧‧‧ Position Alignment Processing Department

304‧‧‧Defect Detection Department

305‧‧‧Comparative Decision Department

306‧‧‧Output Department

201‧‧‧ camera

202‧‧‧ camera

102‧‧‧Light source

101a‧‧‧Light

102a‧‧‧Light

101b‧‧‧Diffuse reflected light

102b‧‧‧Indirect transmission of light

101‧‧‧Light source

S‧‧‧Inspected objects

Claims (12)

A defect inspection device for inspecting a defect of a sheet-like object to be inspected includes: a first irradiation means for irradiating the object with the first light; and a second irradiation means for the object to be inspected Irradiating the second light; the first and second imaging means obtain imaging data corresponding to the intensity of the reflected light of the first light and the transmitted light of the second light; and detecting means are based on the first and the second (2) The intensity of the reflected light and the transmitted light at the same position of the object to be inspected by the photographing means detects an inner layer defect of the test object, and the first irradiation means is from one side of the object to be inspected The first light is irradiated onto the inspection object, and the second irradiation means irradiates the inspection object with the second light from the other side different from the one side, and the first and second imaging means are disposed on the second light. On the one side of the object to be inspected, the first imaging means is disposed to reflect the reflected light of the first light, and the positional relationship between the second irradiation means and the second imaging means is set to be the second light. The positional relationship of the second imaging means is transmitted through the light indirectly through the light. The defect inspection device of claim 1, wherein the second light is blue light. A defect inspection device is a defect inspection device for inspecting a defect of a sheet-like object to be inspected, comprising: The first irradiation means irradiates the first light with the first light, and the second irradiation means irradiates the second light with the second light, and the first and second imaging means obtain the reflection corresponding to the first light. The photographic data of the intensity of the light and the transmitted light of the second light; and the detecting means are the reflected light and the transmitted light at the same position of the object to be inspected obtained by the first and second imaging means Intensity is detected in the inner layer defect of the test object, and the first irradiation means irradiates the test object with the first light from one side of the test object, and the second irradiation means is from the one side The other side of the object is irradiated with the second light, and the first and second imaging means are disposed on the side of the object to be inspected, and the first imaging means is configured to inject the first light. In a manner of reflecting light, a positional relationship between the second irradiation means and the second imaging means is set such that a position of the second light passing through the second imaging means is incident on the second imaging means, and the second irradiation means and the A first polarizing filter is disposed between the inspection objects, and a second bias is disposed between the second imaging means and the inspection object. Filter, and the first and the second polarization filter in a manner orthogonal to the transmission axis of another configuration. The defect inspection device according to any one of claims 1 to 3, wherein The first light irradiation position and the second light irradiation position are different, and the imaging means is composed of two cameras that capture the irradiation position of the first light and the camera that captures the irradiation position of the second light. . The defect inspection device according to any one of claims 1 to 3, wherein the first light irradiation position and the second light irradiation position are the same, and the first light and the second light are different in wavelength from each other; The photographing means is a color camera having a plurality of linear light receiving elements that respectively receive light of different wavelengths. The defect inspection device according to any one of claims 1 to 3, wherein the first light irradiation position and the second light irradiation position are the same, and the first light and the second light are different in wavelength from each other; The photographing means is a color camera having a spectroscopic element that splits light incident on the photographing means and a plurality of light receiving elements that respectively obtain light intensity after splitting. The defect inspection device according to any one of claims 1 to 3, wherein the second light is blue light; the first light is red light or green light. The defect inspection device of claim 4, further comprising a position aligning means for performing aligning with the photographic material of the reflected light and the photographic material relating to the transmitted light; The detecting means detects the inner layer defect of the object to be inspected based on the photographic data after the alignment. The defect inspection device according to any one of claims 1 to 3, wherein the detection means has: a defect detecting means for detecting a defect based on the intensity of the reflected light, and detecting a defect based on the intensity of the transmitted light; and discriminating The means is that the defect that the intensity of the transmitted light is greater than the intensity of the reflected light is an inner layer defect. A defect inspection method for inspecting a defect of a sheet-like object to be inspected, comprising: an irradiation step of irradiating the object with the first light and the second light; and a photographing step of obtaining the first The photographic data of the intensity of the reflected light of the light and the transmitted light of the second light; and the detecting step of the reflected light and the intensity of the transmitted light at the same position of the object to be inspected obtained in the photographing step Detecting an inner layer defect of the inspection object; in the photographing step, the second light is photographed to transmit the transmitted light, and the first light is irradiated to the inspection object from one side of the inspection object; The other side of the side is irradiated with the second light, and the first and second imaging units are disposed on the side of the test object, and are arranged to enter the reflected light of the first light. In the first imaging means, the positive transmitted light of the second light is not incident but indirectly transmitted through the light. The second photographing means is arranged in the manner of entering. A defect inspection method for inspecting a defect of a sheet-like object to be inspected, comprising: an irradiation step of irradiating the object with the first light and the second light; and a photographing step of obtaining the first The photographic data of the intensity of the reflected light of the light and the transmitted light of the second light; and the detecting step of the reflected light and the intensity of the transmitted light at the same position of the object to be inspected obtained in the photographing step Detecting an inner layer defect of the object to be inspected, and capturing the positive light transmitted by the second light in the photographing step, and irradiating the object with the first light from one side of the object to be inspected; The other side of the object is irradiated with the second light; the first and second imaging units are disposed on the side of the object to be inspected, and the reflected light of the first light is incident on the object. In the first imaging means, the second imaging means is disposed such that the positive transmitted light of the second light is incident on the second imaging means, and the second light is applied to the second light via the first polarizing filter. After the object to be inspected is irradiated and transmitted through the object to be inspected, the first polarizing filter is passed through the transmission axis. The second quadrature polarization filters that have been taken. The defect inspection method of claim 10 or 11, wherein the defect detection step is constituted by a step of detecting a defect according to the intensity of the reflected light of the first light; The detecting step detects a defect based on the transmitted light intensity of the second light, and the determining step determines that the defect having the transmitted light intensity of the second light greater than the reflected light intensity of the first light is an inner layer defect.