KR20140011258A - Method of detection of defects and defects detection device - Google Patents

Abstract

The detection accuracy of defects can be improved. A defect detection method comprises: an irradiating step for allowing an object to be detected to be irradiated with visible rays and non-visible rays provided by a light source; a data generating step for respectively receiving visible rays and non-visible rays reflected by the object to be detected or passing through the object to be detected, and generating imaging data corresponding to the received amount of each of the visible rays and non-visible rays; and a determination step for determining, if a result obtained by comparison between the variation of the imaging data in a visible ray area and the variation of the imaging data in a non-visible ray area belongs to a stored detection range, the result as a defect. [Reference numerals] (51) R signal processing unit; (52) G signal processing unit; (53) B signal processing unit; (54) IR/UV signal processing unit; (55) Positioning processing unit; (56) Defect detection unit; (56A) Detection threshold memory unit; (57) Determination unit; (57A) Determination threshold memory unit; (58) Output unit; (AA) Transfer direction

Description

DEFECTS DETECTION DEVICE AND DEFECT DETECTION DEVICES

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

The defect of a sheet-like article can be determined using the RGB image obtained by imaging a sheet-like article with a camera. And from the RGB image data of the sheet-like article which passed the test plate image which has several different color gamut, the composite image which synthesize | combined R component image, G component image, and B component image is acquired, and the said synthesis | combination is carried out. Description of the Related Art A technique for determining a defect type is known depending on whether the color of the discolored region of an image falls within a range of a setting parameter of a defect type stored in advance (see Patent Document 1, for example). According to this technique, a defect is not judged as a defect in defect inspection such as contamination, cracking, and defective shape in a sheet-shaped article having a width (deviation, color stain and / or fading) in color reproducibility, In addition, black pollution, non-black pollution and cracking can be discriminated.

However, since defects are determined by RGB image data in the visible light region, defects similar in color to the sheet material and transparent defects are difficult to detect. For example, it is difficult to detect metal powder adhering to dark colored paper or to detect a transparent liquid such as water or oil.

In addition, when defects are determined by RGB image data in the visible light region, it becomes difficult to classify defects having similar colors. For example, it is difficult to distinguish black metal powder such as iron and dark colored oil. In addition, it is difficult to distinguish between bright metal powder such as aluminum and light oil. In addition, it is difficult to distinguish between water and transparent oil.

On the other hand, even when the appearance is similar, the influence on the function of the inspected object may be different. For example, in the separator used for a secondary battery, even if there is some contamination, it does not become a problem, but there exists a possibility that electricity may be conducted when metal is mixed. For this reason, contamination does not need to be determined as a defect, but metal needs to be determined as a defect. Therefore, there is a need to discriminate between metal powder and contamination having similar colors. Moreover, even if water adheres to the inspected object and if it does not become a problem if it evaporates after that, it is not necessary to determine it as a defect even if water adheres. However, when oil hardly evaporates on the inspected object, it is necessary to determine it as a defect. Therefore, there is a need to discriminate between water of similar color and transparent oil.

Thus, since it may be permissible by the kind of defect of a to-be-tested object, it is preferable to determine the kind of defect. However, this determination is difficult only with RGB image data in the visible light region. Therefore, even if it is not necessary to detect it as a defect, there exists a possibility that it may be detected as a defect.

Patent Document 1: Japanese Patent Application Laid-Open No. 2008-256402

This invention is made | formed in view of the above problem, and the objective is to improve the detection precision of a defect.

In order to achieve the above object, the defect inspection method according to the present invention,

An irradiation step of irradiating visible light and invisible light to the inspection object from a light source;

A data generation step of receiving visible and invisible light that reflects from or passes through the inspected object, respectively, and generates imaging data corresponding to the received amount of light, respectively;

Determination process of judging as a defect, when the result which compared the degree to which the image data was fluctuate | varied in the area | region in which the said image data was fluctuate | varied in visible light and an invisible light falls in the range which becomes a previously stored defect. It is configured to include.

Here, the absorption rate of the light of each wavelength at the time of irradiating the material with the light of the wavelength of a visible region and the light of the wavelength of an invisible region is different for every substance. For this reason, the intensity | strength of the reflected light or transmitted light at the time of irradiating the material with the light of the wavelength of a visible light region, and the light of the wavelength of an invisible light region differs for every material and for every wavelength of light. That is, the intensity of the reflected light or transmitted light when the light of the wavelength of the visible light region and the light of the wavelength of the non-visible light region is irradiated to the inspection object is the intensity corresponding to the defect when the defect is present. For this reason, a difference arises in the imaging data when a defect does not exist in an inspected object and the imaging data when a defect exists in an inspected object. In other words, if a defect exists in the inspected object, the imaging data fluctuates. The degree of variation of the captured image data differs for each material and for each wavelength of light. For this reason, the result of comparing the degree of variation of the imaging data of the light of the wavelength of the visible light region with the degree of the variation of the imaging data of the light of the wavelength of the invisible light region varies depending on the presence or absence of a defect and the type of the defect. Therefore, if the result of comparing the degree of fluctuation of the imaging data of the light of each wavelength is memorize | stored in advance according to the kind of defect, the presence or absence of a defect and the kind of defect can be discriminated. For example, the kind of defect which cannot be discriminated only by visible light by the defect of the color similar to the color of a to-be-tested object can be discriminated by using invisible light together. Therefore, in the case of a defect which is permitted even if there exists a defect, it can also be determined that a defect does not exist.

In the present invention, the invisible light may be at least one of infrared light or ultraviolet light. When the light having these wavelengths is used, the imaging data is more remarkably changed depending on the kind of the substance, so that defects that cannot be judged externally can be detected more accurately.

Moreover, in this invention, the division value which is the value which divided | segmented the imaging data produced | generated by the said data generation process into the imaging data of the to-be-tested object which image | photographed before the defect does not have visible light and a ratio to the extent which the said imaging data changed. Each from visible light,

In the determination step, the kind of defect may be determined by comparing the difference between the dividing value of visible light and the dividing value of invisible light with a value for each kind of defect stored in advance.

By comparing the respective ratios (division values) calculated based on the imaging data without defects as described above, the variation in the amount of light of the light source, the difference in transmittance or reflectance for each defect, the transmittance of the inspected object or The error due to the difference in reflectance can be reduced. Thereby, since it may be hard to be influenced by the influence of disturbance, a defect, or the change of an inspection object, the determination precision of a defect can be improved.

Moreover, in this invention, when irradiating the said infrared light in the said irradiation process, you may irradiate the visible light of a short wavelength side rather than a long wavelength side.

Moreover, in this invention, when irradiating the said ultraviolet light in the said irradiation process, you may irradiate the visible light of a long wavelength side rather than a short wavelength side.

That is, when light with a larger difference in wavelength is shown, the difference in the degree of variation of the imaging data with respect to the defect is more remarkable, so that the accuracy of determining the defect can be improved. The visible light on the shorter wavelength side than the long wavelength side may be visible light having a wavelength shorter than the wavelength serving as the center of the visible light region or may be a B component in the visible light. The visible light on the longer wavelength side than the short wavelength side may be visible light having a wavelength longer than the wavelength serving as the center of the visible light region, or may be an R component in the visible light.

Moreover, in this invention, when the difference between the said dividing value of visible light and the said dividing value of invisible light is below a threshold value, you may judge as a defect containing a metal.

Here, even if the irradiated light is light having a wavelength in the visible light region or in the invisible light region, the imaging data fluctuates equally if it is a metal. In other words, the difference in the degree of fluctuation of the imaging data is small. For this reason, when the difference of the degree of the fluctuation | variation of the imaging data is below a threshold, it can determine with the defect containing a metal. This threshold is an upper limit of the difference of the degree of the fluctuation | variation of the imaging data when a metal is contained in a defect. In addition, since the degree of variation in the imaging data changes depending on the type of metal, the type of metal can be determined in accordance with the degree of variation in the imaging data.

In the present invention, the visible light and the invisible light can be received by the Si-based semiconductor light receiving element, respectively. According to the Si type semiconductor light receiving element, infrared light, visible light, and ultraviolet light can be received. In addition, since the pixel can be made inexpensively, a wide range of measurements and a high speed measurement are possible.

In the present invention, one camera may be provided with elements that receive visible light and invisible light, respectively. In this way, the size of the apparatus can be reduced.

In the present invention, the visible light and the invisible light may be spectroscopically analyzed with a spectroscopic element to receive the visible light and the invisible light, respectively. By doing in this way, the alignment for correcting the difference of the imaging position of the light of each wavelength becomes unnecessary, and the process can be simplified.

In the present invention, the light source may be a light source with a limited wavelength range.

In the present invention, the wavelength region may be limited by the wavelength filter for the light irradiated from the light source.

In this way, by limiting the wavelength range, light having a wavelength of more significant interaction with the substance can be used, so that the accuracy of determination of defects can be improved.

Moreover, in order to achieve the said subject, the defect inspection apparatus by this invention is

An irradiation section for irradiating visible light and invisible light to the inspection object from the light source,

A data generation unit for receiving visible and invisible light that reflects from or passes through the object to be inspected, and generates imaging data corresponding to the amount of received light, respectively;

When the result of comparing the degree of fluctuation of the image data in the region where the image data has changed with visible light and invisible light is within the range of the previously stored defect, a determination unit for judging it as a defect. Equipped.

According to this invention, the detection precision of a defect can be improved.

1 is a block diagram of a defect inspection apparatus according to a first embodiment.
2 is a diagram illustrating a relationship between a pixel and a reflection ratio after processing in each signal processing unit.
3 is a diagram in which each of the signals shown in FIG. 2 is overlapped with each other;
4 is a diagram showing a relationship between a pixel and a reflection ratio when the defect is water;
5 is a diagram showing a relationship between a pixel and a reflection ratio when the defect is a metal;
Fig. 6 is a flowchart showing a flow for determining the type of defects according to the first embodiment.
7 is a block diagram of a defect inspection apparatus according to a second embodiment.
8 is a block diagram of a defect inspection apparatus according to the third embodiment.
9 is a diagram showing an arrangement of sensors according to Example 3. FIG.
10 is a block diagram of a defect inspection apparatus according to a fourth embodiment.
11 is a diagram showing an internal structure of a camera according to the fourth embodiment.

EMBODIMENT OF THE INVENTION Hereinafter, with reference to drawings, the form for implementing this invention is demonstrated in detail based on an Example. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this example are not intended to limit the scope of the present invention only to them unless otherwise specified.

(Example 1)

1 is a block diagram of a defect inspection apparatus 1 according to the present embodiment. The defect inspection apparatus 1 includes a visible light source 31 for irradiating visible light to the inspected object 2, an IR / UV light source 32 for irradiating at least one of ultraviolet light or infrared light to the inspected object 2; And a visible light camera 41 for receiving visible light reflected from the inspected object 2, an IR / UV light camera 42 for receiving ultraviolet light or infrared light reflected from the inspected object 2, and a visible light camera 41 And the processing apparatus 5 which processes the light received by the IR / UV optical camera 42 to detect the defect and determine the type of the defect.

The inspected object 2 is formed in a sheet shape, for example, and is conveyed in the arrow direction of FIG. In addition, the to-be-tested object 2 does not need to be a sheet form. As the inspection object 2, paper, a film, resin, cellulose, etc. can be illustrated. The test object 2 may be a separator used for a secondary battery, an optical sheet used for liquid crystal, or the like. In addition, in this embodiment, although the light source 3 and the camera 4 are fixed and the to-be-tested object 2 is moved, instead, the to-be-tested object 2 is fixed and the light source 3 and the camera ( 4) may be moved.

The defect inspection apparatus 1 receives the reflected light of the light irradiated from the visible light source 31 and the IR / UV light source 32 to the test object 2 by the visible light camera 41 and the IR / UV light camera 42. A defect is extracted based on the image obtained by this. Also, the type of defect is determined. The defect inspection apparatus 1 can detect a foreign material, a hole, a wrinkle, a stain, etc. as a defect.

In addition, when the visible light source 31 and the IR / UV light source 32 are not distinguished, it is only called "light source 3." In the case where the visible light camera 41 and the IR / UV light camera 42 are not distinguished, only the "camera 4" is called. The light source 3 may be one in which a wavelength range such as an LED is limited, or one in which the wavelength range is limited using a wavelength filter. Further, by using the wavelength with which the interaction with the substance is more significant, the accuracy of detection of defects and determination of defect types is improved. In the present embodiment, the visible light source 31 and the IR / UV light source 32 correspond to the irradiation section in the present invention. In addition, in this embodiment, irradiating light to the inspected object 2 by the visible light source 31 and the IR / UV light source 32 corresponds to the irradiation process in the present invention.

The camera 4 is comprised, for example with the CCD image sensor which arrange | positioned 4096 light receiving elements in series. In each light receiving element, light is converted into electric charge in response to the amount of light received. For this reason, in the light receiving element where the light reflected by the defect forms an image, the amount of electric charge is small with respect to the other light receiving element. In addition, in this embodiment, the visible light camera 41 is provided with three CCD image sensors for each component of R, G, and B. As shown in FIG. Moreover, the IR / UV optical camera 42 is equipped with the CCD image sensor which detects at least one of an infrared light or an ultraviolet light. Electric charges output from each light receiving element are input to the processing apparatus 5 as image pickup data. In the present embodiment, the visible light camera 41 and the IR / UV light camera 42 correspond to the data generating unit in the present invention. In this embodiment, the generation of the imaging data by the visible light camera 41 and the IR / UV light camera 42 corresponds to the data generation step in the present invention.

In addition, in this embodiment, a plurality of cameras 4 are arranged in the width direction of the inspected object 2 in accordance with the width of the inspected object 2 so that the entire width of the inspected object 2 can be captured by the camera 4. It may be provided. In addition, the visible light camera 41 and the IR / UV light camera 42 are arranged shifted in the conveyance direction.

In addition, the processing device 5 includes an R signal processing unit 51, a G signal processing unit 52, and a B signal processing unit 53 for processing the imaging data output from the visible light camera 41 for each of the RGB components, An IR / UV signal processor 54 for processing the imaging data output from the IR / UV optical camera 42 is provided. The R signal processor 51 processes the R component signal (R signal), the G signal processor 52 processes the G component signal (G signal), and the B signal processor 53 processes the B component signal ( B signal), and the IR / UV signal processing section 54 processes infrared or ultraviolet light signals (IR / UV light signals). By this process, the reflection ratio for each light receiving element (pixel) is obtained.

Here, the reflection ratio is a value obtained by dividing the electric charges (imaging data) of each light receiving element by the electric charges (imaging data) of each light receiving element when there is no defect obtained in advance. That is, the imaging data of the to-be-tested object 2 without a defect is calculated | required previously, and let ratio of the imaging data at the time of defect determination with respect to this value be a reflection ratio. The "charge of each light receiving element when there is no defect previously calculated | required" may be made into the average value of the charge of each light receiving element at the time of image pick-up multiple times. This reflection ratio becomes smaller as the reduction degree of light reception amount is larger, and is correlated with the degree to which the image pickup data has fluctuated. And when there is no defect, a reflection ratio becomes a value near one. The reflection ratio is calculated for each of the R signal, the G signal, the B signal, and the IR / UV optical signal. In addition, in this Example, a reflection ratio corresponds to the division value in this invention.

Here, FIG. 2 is a diagram showing the relationship between the pixel and the reflection ratio after being processed by each signal processing unit 51, 52, 53, 54. The horizontal axis is pixels, and the vertical axis is reflection ratio. In the pixel of the part where the defect imaged, the reflection ratio falls. The degree of degradation is different for the R signal, the G signal, the B signal, and the IR / UV optical signal. In addition, even when a defect does not exist in the inspected object 2, the reflection ratio is slightly different in each pixel under the influence of unevenness on the surface of the inspected object 2 or the like.

Moreover, the processing apparatus 5 is equipped with the alignment processing part 55 which performs alignment of the reflection ratio obtained from the visible light camera 41, and the reflection ratio obtained from the IR / UV optical camera 42. As shown in FIG. Here, since the visible light camera 41 and the IR / UV light camera 42 are arranged to be shifted in the conveyance direction of the inspected object 2, the point picked up by the visible light camera 41 is the IR / UV light. It takes time to reach the position picked up by the camera 42. In order to compare the reflection ratio of the same place obtained from the visible light camera 41 and the IR / UV light camera 42, the alignment processing unit 55 includes the reflection ratio of the visible light camera 41 and the IR / UV light camera ( Alignment with the reflection ratio of 42) is performed.

Here, since the conveyance speed of the inspected object 2 and the distance from the visible light camera 41 to the IR / UV light camera 42 are set in advance, based on these values, the image captured by the visible light camera 41 is captured. The time delay until the point is picked up by the IR / UV optical camera 42 can be calculated. In other words, by aligning the data by this time delay, the alignment can be performed. Similarly, in the case where imaging different locations are respectively taken from the R signal, the G signal, and the B signal, or when imaging different locations from the ultraviolet light and the infrared light, they are aligned.

Moreover, the processing apparatus 5 is provided with the defect detection part 56 which detects a defect, and the detection threshold value storage part 56A which stores the threshold of the magnitude | size of a defect. This threshold value is stored in advance as a lower limit of the magnitude that needs to be detected as a defect. This threshold value is determined by the type of the inspected object 2, the user's request, or the like.

Here, even if there is a defect, when the defect is small, it may be allowed. The size of a defect when exceeding this allowed range is set as a threshold. That is, the defect detection part 56 determines that a defect exists when the magnitude | size of a defect is more than a threshold value, and determines that there is no defect, when the magnitude | size of a defect is less than a threshold value. The size of the defect is represented by the decrease in the reflection ratio and the number of pixels in which the reflection ratio is reduced. For example, the magnitude of a defect can be calculated | required based on the waveform shown in FIG. In addition, when any reflection ratio becomes below a threshold, you may detect as a defect. In addition, when the pixel whose reflection ratio falls below the threshold is above the threshold, it may be detected as a defect.

Moreover, the processing apparatus 5 is equipped with the determination part 57 which determines the kind of defect, and the determination threshold value storage part 57A which stores the threshold value for determining the kind of defect, when a defect is detected. The determination unit 57 determines the kind of the defect based on the relationship between the pixel processed by each signal processing unit 51, 52, 53, 54 and the reflection ratio. Then, the presence or absence of a defect and the kind of the defect are output from the output unit 58. In addition, in this embodiment, determining the kind of defect by the determination part 57 is corresponded to the determination process in this invention.

3 is a diagram in which the signals shown in FIG. 2 are superimposed on each other. Thus, the degree of fall of the reflection ratio of each signal differs, respectively. The degree of decrease in the reflection ratio of each signal is a value unique to each substance. Here, for example, since the wavelength of ultraviolet light is close to the binding energy of a molecule and an atom, it is easy to be absorbed by a substance. In addition, since the wavelength of ultraviolet light is relatively short, it is easy to scatter. On the other hand, since the wavelength of infrared light is close to the vibration energy of a molecule, it is easy to be absorbed by a substance. Moreover, since the wavelength of infrared light is comparatively long, it is hard to scatter. By using the interaction between the light of each wavelength and the substance, the kind of defect can be determined.

For example, FIG. 4 is a diagram showing the relationship between the pixel and the reflection ratio when the defect is water. Although the reflection ratio of the pixel in which a defect forms an image becomes low compared with the reflection ratio of another pixel, this fall amount (it may be set as a reduction rate) is visible light, an infrared light, or an ultraviolet light (hereinafter, IR / Also called UV light). Therefore, in the pixel where water is formed, a difference occurs between the reflection ratio of visible light and the reflection ratio of infrared light (IR light).

The difference between the reflectance ratio of visible light and the reflectance ratio of IR / UV light is unique to the material. In other words, when irradiated visible light and IR / UV light to a material, the absorption rate of each light is different for each material, so that the ratio of each light reflected from the material and the rate at which each light transmits the material are different for each material. . For this reason, in the pixel in which a defect forms an image, the reflection ratio of visible light and IR / UV light becomes a value corresponding to the substance which forms a defect.

Therefore, if the difference between the reflectance ratio of visible light and the reflectance ratio of IR / UV light is obtained beforehand by experiment or calculation for each substance that may be mixed, the kind of defect can be determined based on the difference of the reflectance ratio. have.

5 is a diagram showing the relationship between the pixel and the reflection ratio when the defect is a metal. In the case where the defect is a metal, the difference between the two reflectance ratios is small because the reflectance ratio of visible light and the reflectance ratio of IR / UV light are almost the same. For this reason, when the difference between the reflection ratio of visible light and the reflection ratio of IR / UV light (which may be the absolute value of the difference) is less than or equal to the threshold value, it can be determined that the defect is a metal. This threshold value can be obtained by experiment or the like in advance. In addition, since the reflection ratio changes depending on the type of metal, it is possible to determine the type of metal based on the reflection ratio. For example, in the case where the inspected object 2 is a sheet which insulates electricity, there is no problem if the conduction of electricity can be interrupted even if there is contamination, but there is a problem because electricity is conducted when metal is mixed in the sheet. Therefore, if it is possible to determine whether the defect is a metal, contamination can be allowed and only the metal can be detected as the defect.

Thus, the kind of defect can be discriminated according to the difference between the reflection ratio of visible light and the reflection ratio of IR / UV light. Here, by using the difference of the reflection ratio, the influence of the state of the to-be-tested object 2 and a defect, and the influence of the fluctuation | variation of light quantity can be made small. For example, the light receiving amount of the light receiving element changes depending on the color of the inspected object 2 or the color of the defect. In addition, when the amount of light varies, the amount of light received by the light receiving element changes, so that the reflection ratio changes even without a defect. In this way, the reflection ratio of visible light and IR / UV light can change even without a defect. On the other hand, by taking the difference between the reflection ratio of visible light and the reflection ratio of IR / UV light, it is possible to erase the change in the light reception amount of each light receiving element due to the variation in the light amount. That is, since the influence of the color of the inspected object 2, the influence of the state of a surface, and the fluctuation | variation of a light quantity can be made small, the detection precision of a defect and the determination precision of the classification of a defect can be improved.

In addition, instead of the difference between the reflectance ratio of visible light and the reflectance ratio of IR / UV light, the kind of defect may be determined using ratio.

In addition, visible light may discriminate | determine the kind of defect using only one or two of R component, G component, and B component. In addition, one or both of infrared light or ultraviolet light may be used to determine the type of defect. In addition, when selecting any one of R component, G component, and B component and an infrared light or an ultraviolet light, what is necessary is just to select the combination which becomes large in a difference of a wavelength. For example, the combination with ultraviolet light having a short wavelength is an R component having a long wavelength even in the visible light, and the combination with an infrared light having a long wavelength is a B component having a short wavelength even in the visible light. Thereby, since the difference of the reflection ratio of a defect appears more remarkably, determination precision can be improved.

In addition, a Si (silicon) -based semiconductor may be used for the light receiving element of the camera 4. By using a Si-based semiconductor light receiving element, any of ultraviolet light, visible light and infrared light can be detected. In addition, multiple pixels can be made, a wide range or high speed measurement can be performed, and cost can also be suppressed low.

Next, FIG. 6 is a flowchart showing a flow for determining the kind of defects according to the present embodiment.

In step S101, the inspection object 2 is imaged by the camera 4, and this data is received by the processing device 5.

In step S102, the signal output from the camera 4 is processed by each of the R signal processing unit 51, the G signal processing unit 52, the B signal processing unit 53, and the IR / UV signal processing unit 54. Each signal processor calculates a reflection ratio for each pixel.

In step S103, alignment of the data processed by each signal processing unit is performed. The alignment processing unit 55 performs alignment based on the conveyance speed of the inspected object 2 and the distance of each camera 4.

In step S104, the defect is detected by the defect detector 56. For example, the defect detection part 56 detects as a defect, when the magnitude | size of a defect is more than the threshold stored by the detection threshold value storage part 56A. For example, when any one reflection ratio is below the threshold stored by the detection threshold value storage part 56A, you may detect as a defect.

In step S105, it is determined whether or not a defect is detected in step S104. If affirmative determination is made in step S105, the flow proceeds to step S106. On the other hand, when a negative determination is made in step S105, this routine is ended as if there is no defect.

In step S106, the type of the defect is determined by the determination unit 57. The determination unit 57 classifies the defect by comparing the difference between the reflection ratio of the visible light and the reflection ratio of the IR / UV light and the threshold stored in the determination threshold storage unit 57A. For example, when the difference between the reflection ratio of visible light and the reflection ratio of IR / UV light is less than or equal to the threshold, it is determined that the defect is a metal. Then, the type of metal is determined based on the reflection ratio for each metal stored in advance. For example, since water easily absorbs infrared light with respect to oil, oil and water can be discriminated by using a relatively large difference between the reflection ratio of B component of visible light and the reflection ratio of infrared light. . In addition, the determination threshold storage unit 57A may store a difference between the reflection ratio between visible light and IR / UV light and a relationship with a substance, and may specify a substance according to this relationship.

In step S107, the defect is detected and the type of the defect is output from the output unit 58. At this time, for example, an image of a defect may be output. In addition, the position where the defect exists and the kind of the defect may be stored, or the mark may be displayed on the position where the defect exists. In addition, an alarm may be issued when there is a defect, or a defect may be present or the type of the defect may be displayed on the display. In addition, if the kind of defect determined in step S106 is acceptable, it is output that there is no defect.

As explained above, according to this embodiment, the defect of the to-be-tested object 2 can be detected and the kind of defect can be discriminated. And the defect which cannot be detected only by visible light can be detected using interaction with the substance by ultraviolet light or infrared light. Moreover, the kind of defect which cannot be discriminated only by visible light as a defect of the color similar to the to-be-tested object 2 can be discriminated by using invisible light together. In addition, any of ultraviolet light, visible light, and infrared light can be detected by using a Si-based semiconductor light receiving element. In addition, multiple pixels can be made, a wide range or high speed measurement can be performed, and cost can also be suppressed low. In addition, by reflecting the reflection ratio on the basis of the normal part and comparing the reflection ratio with visible light and IR / UV light, errors due to variations in the amount of light and differences in the reflection ratio for each defect can be reduced. have. Therefore, it is hard to be affected by the change of the disturbance or the state of the defect.

(Practical example 2)

7 is a block diagram of the defect inspection apparatus 1 according to the present embodiment. This embodiment differs from Example 1 in that the light source 3 is provided on the side opposite to the inspection object 2 with respect to the camera 4. Since other devices and the like are the same as those in the first embodiment, description thereof is omitted.

In this embodiment, the defect is detected and the defect type is determined based on the transmission ratio between the visible light in the inspected object 2 and the ultraviolet light or the infrared light. Here, the transmission ratio is a value obtained by dividing the electric charge (imaging data) of each light receiving element by the electric charge (imaging data) of each light receiving element when there is no defect previously obtained. That is, the imaging data of the to-be-tested object 2 without a defect is calculated | required previously, and let ratio of the imaging data at the time of defect determination with respect to this value be a transmission ratio. The "charge of each light receiving element when there is no defect previously calculated | required" may be made into the average value of the charge of each light receiving element at the time of image pick-up multiple times. This transmission ratio becomes smaller as the reduction degree of light reception amount is larger, and is correlated with the degree to which the image pickup data has fluctuated. In the absence of a defect, the transmission ratio is a value close to one. The transmission ratio is calculated for each of the R signal, the G signal, the B signal, and the IR / UV optical signal. In addition, in a present Example, a transmission ratio corresponds to the division value in this invention.

The transmission ratios of visible light, ultraviolet light and infrared light are different for each material as in the reflection ratio described in Example 1. For this reason, a difference occurs in the transmission ratio between visible light and IR / UV light in the pixel where the defect is formed. This difference is a value unique to the substance. That is, when visible light and IR / UV light are irradiated to a material, since the absorption rate of each light in the material is different for each material, the rate at which each light exits the material is different for each material.

Therefore, if the difference between the transmission ratio of visible light and the transmission ratio of IR / UV light is obtained beforehand by experiment or calculation for each substance that may be mixed, the kind of defect can be determined based on the difference of the transmission ratio. have.

In addition, depending on the kind of the inspection object 2 or the kind of substance which may be mixed, it may be determined whether the type of the defect is determined by the transmission ratio or the reflection ratio. For example, it may be determined by experiment or the like which one is more suitable. Further, for example, when the inspected object 2 is thin, the transmittance ratio is used, and when the inspected object 2 is thick, it may be selected depending on the thickness of the inspected object 2. In addition, you may use both transmitted light and reflected light.

(Example 3)

8 is a block diagram of the defect inspection apparatus 1 according to the present embodiment. In this embodiment, only one camera 4 is provided. This single camera 4 serves as a visible light camera 41 and an IR / UV light camera 42 according to the first embodiment. That is, the camera 4 which concerns on a present Example is equipped with the light receiving element which measures at least 1 component of R, G, and B, and the light receiving element which measures at least one of infrared light or an ultraviolet light. The visible light source 31 and the IR / UV light source 32 emit light at the same place. Since other devices and the like are the same as those in the first embodiment, description thereof is omitted.

9 is a diagram showing the arrangement of the sensors. R detects R component in visible light, G detects G component in visible light, B detects B component in visible light, and IR / UV detects infrared light or ultraviolet light to be. Each sensor of R, G, B, and IR / UV is arrange | positioned shifting in the conveyance direction. For this reason, similarly to Example 1, alignment of the output signal of each sensor is needed. By using such a camera 4, the apparatus can be miniaturized.

(Example 4)

10 is a block diagram of the defect inspection apparatus 1 according to the present embodiment. 11 is a diagram showing the internal structure of the camera 4. R detects an R component in visible light, G detects a G component in visible light, B detects a B component in visible light, and IR / UV detects infrared light or ultraviolet light. to be. This embodiment is the same as the third embodiment in that one camera 4 is provided, but after measuring the visible light and the IR / UV light using the spectroscopic element 43, the respective light receiving elements are measured. It differs from Example 3.

That is, in this embodiment, since the light propagated in the same direction is spectroscopically detected by the spectroscopic element 43 and received by each sensor, the visible light and the IR / UV light reflected from the same position of the inspected object 2 are collected by one camera ( 4) can be taken. And since the data of the same position can be obtained simultaneously, alignment is unnecessary. For this reason, the alignment processing part 55 required by the said Embodiments 1-3 is unnecessary. Since other apparatuses etc. are the same as Example 3, description is abbreviate | omitted.

By using such a camera 4, the need for alignment is eliminated, so that the processing can be simplified. In addition, the accuracy of alignment is not affected.

1: defect inspection device
2: test object
5: Processing device
31: visible light source
32: IR / UV light source
41: visible light camera
42: IR / UV light camera
43: spectral element
51: R signal processing unit
52: G signal processing unit
53: B signal processing unit
54: IR / UV signal processing unit
55: alignment processing unit
56: defect detection unit
56A: detection threshold memory
57: judgment unit
57A: Decision threshold storage
58: output unit

Claims (12)

An irradiation step of irradiating visible light and invisible light to the inspection object from a light source;
A data generation step of receiving visible and invisible light that reflects from or passes through the inspected object, respectively, and generates imaging data corresponding to the received amount of light, respectively;
Determination process of judging as a defect, when the result which compared the degree to which the image data was fluctuate | varied in the area | region in which the said image data was fluctuate | varied in visible light and an invisible light falls in the range which becomes a previously stored defect. Defect inspection method comprising a. The method of claim 1,
The invisible light is at least one of infrared light or ultraviolet light. 3. The method according to claim 1 or 2,
The dividing value, which is a value obtained by dividing the image pickup data generated in the data generation step by the image pickup data of an inspection-free object to be picked up in advance, is obtained from visible light and invisible light, respectively, as the degree of variation of the image pickup data,
In the determination step, the type of defect is determined by comparing the difference between the dividing value of visible light and the dividing value of invisible light with a value for each kind of defect stored in advance. . 3. The method of claim 2,
When irradiating the said infrared light in the said irradiation process, the visible light of a short wavelength side is irradiated rather than a long wavelength side, The defect inspection method characterized by the above-mentioned. 3. The method of claim 2,
When irradiating the said ultraviolet light in the said irradiation process, the visible light of long wavelength side is irradiated rather than a short wavelength side, The defect inspection method characterized by the above-mentioned. The method of claim 3,
And when the difference between the dividing value of visible light and the dividing value of invisible light is equal to or less than a threshold, a defect including a metal is determined. 3. The method of claim 2,
A defect inspection method comprising receiving visible light and invisible light with a Si-based semiconductor light receiving element, respectively. 3. The method of claim 2,
The one camera is equipped with the element which receives visible light and an invisible light, respectively, The defect inspection method characterized by the above-mentioned. 3. The method of claim 2,
A visible light and an invisible light are spectroscopically analyzed to receive visible and invisible light, respectively. 3. The method of claim 2,
And the light source is a light source having a limited wavelength range. 3. The method of claim 2,
The wavelength inspection ranges the light irradiated from the said light source through a wavelength filter, The defect inspection method characterized by the above-mentioned. An irradiation section for irradiating visible light and invisible light to the inspection object from the light source,
A data generation unit for receiving visible and invisible light that reflects from or passes through the object to be inspected, and generates imaging data corresponding to the amount of received light, respectively;
When the result of comparing the degree of fluctuation of the image data in the region where the image data has changed with visible light and invisible light is within the range of the previously stored defect, a determination unit for judging it as a defect. The defect inspection apparatus characterized by the above-mentioned.

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