TWI498544B - Defect inspection method and defect inspection device - Google Patents

Description

Defect inspection method and defect inspection device

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

A technique is known (for example, refer to Patent Document 1) which determines the defect of a sheet-like article using an RGB image obtained by photographing a sheet-like article with a camera. Further, the synthesized image synthesized by the R component image, the G component image, and the B component image is obtained from the RGB image data of the sheet-like article on the inspection board having a plurality of different color regions, and based on the composite image Whether the color of the color-changing area belongs to the range of the setting parameters of the defect type that is memorized in advance determines the type of the defect. According to the present technology, when the defect of color has a range (unevenness, color unevenness, and/or color fading), the defect of the sheet-like article, such as dirt, crack, shape, and the like, may not be judged as Defects, and can distinguish black dirt, non-black dirt and cracks.

However, since the defect is determined based on the RGB image data of the visible light region, the defect similar to the sheet material or the transparent defect is difficult to detect. For example, detection of metal powder adhering to a dark paper or detection of a transparent liquid such as water or oil is difficult.

Further, when the defect is determined based on the RGR image data of the visible light region, it is difficult to distinguish the defect having a similar color. For example, to discriminate iron It is difficult to wait for black metal powder and dark oil. Moreover, the discrimination between the bright metal powder such as aluminum and the light oil is also difficult. Furthermore, the discrimination between water and transparent oil is also difficult.

On the other hand, even in the case of similar appearance, there is a case where the influence of the function of the object to be inspected is different. For example, in the separator used in the secondary battery, even if there is some dirt, there is no problem, but when metal is mixed, there may be electrical conduction. Therefore, the dirt system does not have to be determined as a defect, but the metal system needs to be judged as a defect, and therefore, there is a demand for discriminating metal powder and dirt having similar colors. Further, even if water adheres to the test object, it will not be a problem if it evaporates later, and it is not necessary to determine that it is a defect even if water adheres. However, in the case where the oil which is difficult to evaporate adheres to the test object, it is necessary to determine that it is a defect. Therefore, there are also requirements for discriminating water of similar color and transparent oil.

Therefore, since the type of the defect according to the object to be inspected is also allowed, it is preferable to determine the type of the defect. However, it is difficult to perform this discrimination only by the RGB image data in the visible light region. Therefore, even if it is not detected as a defect, there may be a flaw detected as a defect.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2008-256402

The present invention has been developed in view of the above problems, and The purpose is to improve the detection accuracy of defects.

In order to achieve the problem, the defect inspection method of the present invention includes the following steps: an irradiation step of irradiating visible light and invisible light to the test object from the light source; and a data generation step of respectively receiving or reflecting the test object. The visible light and the invisible light of the object to be inspected are respectively generated with image data corresponding to the respective amounts of received light; and the determining step is to compare the degree of change of the image data in the region where the image data is changed by comparing visible light and invisible light. The result is a case in which the pre-memory is regarded as a defect, and it is judged as a defect.

Here, the absorption rate of light of each wavelength when the light of the wavelength of the visible light region and the light of the wavelength of the invisible region are irradiated to the substance differs depending on each substance. Therefore, the intensity of the reflected light or the transmitted light when the light of the wavelength of the visible light region and the light of the wavelength of the invisible region are irradiated to the substance differs depending on the wavelength of each substance and light. In other words, when the intensity of the reflected light or the transmitted light when the light of the wavelength of the visible light region and the wavelength of the invisible light are irradiated onto the test object is in the presence of the defect, the strength corresponding to the defect is obtained. Therefore, the image pickup data in the case where the inspection object defect does not exist is inferior to the image pickup data in the case where the inspection object defect exists. That is, when the object to be inspected has a defect, the image data changes. Moreover, the degree of variation of the image data varies depending on the wavelength of each substance and light. Therefore, the result of comparing the degree of fluctuation of the imaging data of the light of the wavelength of the visible light region and the degree of fluctuation of the imaging data of the light of the wavelength of the invisible light region changes depending on the presence or absence of the defect and the type of the defect. Therefore, if the memory ratio is determined in advance in response to the type of defect As a result of the degree of change in the imaging data of the light of each wavelength, it is possible to discriminate the presence or absence of the defect and the type of the defect. Further, for example, by using invisible light in combination, it is possible to discriminate the type of defect in which the color is similar to the color of the object to be inspected and which cannot be discriminated by visible light alone. Therefore, it is possible to determine that the defect does not exist even if there is a defect but it is tolerable.

Further, in the present invention, at least one of the invisible light may be infrared light or ultraviolet light. When light of these wavelengths is used, since the image data changes more remarkably depending on the type of the substance, it is possible to more accurately detect a defect that cannot be judged by the appearance.

Further, in the present invention, the division value may be obtained by the visible light and the invisible light, respectively, and the division value is the division of the image data generated in the data generation step by the pre-shooting defect-free one. The value of the image data of the inspection object; in the determination step, the type of the defect is determined by comparing the difference between the division value of the visible light and the division value of the invisible light and the value of the type of each of the defects memorized in advance.

By comparing the ratios (division values) obtained by using the non-defective imaging data as a reference, the variation in the amount of light of the light source, the difference in transmittance or reflectance of each defect, the transmittance of the object to be inspected, or The error caused by the difference in reflectivity. Therefore, since it is not easily affected by the disturbance or the influence of the defect or the change of the object to be inspected, the accuracy of the determination of the defect can be improved.

Further, in the present invention, when the infrared light is irradiated in the irradiation step, visible light on the short-wavelength side shorter than the wavelength on the long wavelength side may be irradiated.

Moreover, in the present invention, the purple light may be irradiated in the irradiation step. In the case of external light, visible light on the long wavelength side longer than the short wavelength side is irradiated.

In other words, if the light having a larger difference in wavelength is more prominently displayed due to the difference in the degree of change in the defect of the image data, the accuracy of the determination of the defect can be improved. Further, the visible light system on the short-wavelength side shorter than the long-wavelength side wavelength may be visible light having a wavelength shorter than the wavelength of the center of the visible light region, or a B component in visible light. Further, the visible light of the long-wavelength side longer than the short-wavelength side wavelength may be visible light of a wavelength longer than the wavelength of the center of the visible light region, or may be an R component of visible light.

Further, in the present invention, it is also possible to determine that the metal is a defect when the difference between the division value of visible light and the division value of invisible light is equal to or less than the threshold value.

Here, regardless of whether the light to be irradiated is a wavelength of a visible light region or an invisible light region, the image pickup data fluctuates as long as it is a metal. That is, the degree of change in the image data is small. Therefore, when the difference in the degree of change in the image data is equal to or less than the threshold value, it can be determined that the metal contains a defect. The threshold value is a limit value above the difference in the degree of change in the image data when the defect contains metal. Further, since the degree of fluctuation of the image data varies depending on the type of the metal, the type of the metal can be determined in accordance with the degree of change in the image data.

Moreover, in the present invention, visible light and invisible light can be respectively received by the Si-based semiconductor light-receiving elements. According to the Si-based semiconductor light-receiving element, infrared light, visible light, and ultraviolet light can be received. Moreover, since multi-pixelization can be performed at a low price, measurement over a wide range or at a high speed can be performed.

Further, in the present invention, it is also possible to provide an element for receiving visible light and invisible light in one camera. In this way, the device can be miniaturized.

Further, in the present invention, the visible light and the invisible light may be split by the spectral element, and the visible light and the invisible light may be respectively received. According to this configuration, since the alignment for correcting the difference in the imaging positions of the lights of the respective wavelengths is not required, the processing can be simplified.

Further, in the present invention, the light source may be a light source that is limited in the wavelength region.

Further, in the present invention, the light irradiated from the light source may be passed through the wavelength filter to restrict the wavelength region.

In this way, by limiting the wavelength region, since the light of a wavelength more prominent in interaction with the substance can be used, the accuracy of the determination of the defect can be improved.

Moreover, in order to achieve the problem, the defect inspection apparatus of the present invention includes an illuminating unit that illuminates the object to be inspected with visible light and invisible light from a light source, and the data generating unit receives the object to be inspected or transmitted through the object to be inspected. The visible light and the invisible light respectively generate image data corresponding to the respective amounts of received light; and the determination unit is a result of the degree of change of the image data in the region where the image data is changed by comparing visible light and invisible light. In the case where the pre-memory is within the range of the defect, it is determined to be a defect.

According to the present invention, the detection accuracy of defects can be improved.

1‧‧‧ Defect inspection device

2‧‧‧Inspected objects

5‧‧‧Processing device

31‧‧‧ Visible light source

32‧‧‧IR/UV light source

41‧‧‧ Visible light camera

42‧‧‧IR/UV light camera

43‧‧‧Spectral components

51‧‧‧R Signal Processing Department

52‧‧‧G Signal Processing Department

53‧‧‧B Signal Processing Department

54‧‧‧IR/UV Signal Processing Department

55‧‧‧ Position Alignment Processing Department

56‧‧‧Defect Detection Department

56A‧‧‧Detection threshold memory

57‧‧‧Decision Department

57A‧‧‧Determined Threshold Memory

58‧‧‧Output Department

Fig. 1 is a block diagram of a defect inspection device of the first embodiment.

Fig. 2 is a view showing the relationship between the pixel and the reflectance after processing by each signal processing unit.

Fig. 3 is a diagram in which the signals shown in Fig. 2 are superimposed.

Fig. 4 is a view showing the relationship between the pixel and the reflectance in the case where the defect is water.

Fig. 5 is a view showing the relationship between the pixel and the reflectance in the case where the defect is a metal.

Fig. 6 is a flow chart showing the flow of determining the type of the defect of the first embodiment.

Fig. 7 is a block diagram of the defect inspection device of the second embodiment.

Figure 8 is a block diagram of a defect inspection device of the third embodiment.

Fig. 9 is a view showing the configuration of the sensor of the third embodiment.

Figure 10 is a block diagram of a defect inspection device of the fourth embodiment.

Fig. 11 is a view showing the internal structure of the camera of the fourth embodiment.

[Formation of the Invention]

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 invention unless otherwise specified.

(First embodiment)

Fig. 1 is a block diagram of the defect inspection apparatus 1 of the present embodiment. The defect inspection device 1 includes a visible light source 31 and a visible light source. The IR/UV light source 32 emits at least one of ultraviolet light or infrared light to the test object 2; the visible light camera 41 receives visible light reflected by the test object 2; and the IR/UV light camera 42. The ultraviolet light or the infrared light reflected by the test object 2 is received; and the processing device 5 processes the light received by the visible light camera 41 and the IR/UV light camera 42, and detects the defect and the type of the defect.

The test object 2 is formed, for example, in a sheet shape, and is conveyed in the direction of the arrow in the first drawing. Further, the object 2 to be inspected does not have to be in the form of a sheet. For example, the inspection object 2 may also be paper, film, resin, cellulose, or the like. Further, the test object 2 may be a separator used for a secondary battery, an optical sheet used for a liquid crystal, or the like. Further, in the present embodiment, the light source 3 and the camera 4 are fixed and the object 2 is moved, but the object 2 to be inspected can be fixed, and the light source 3 and the camera 4 can be moved instead of the above.

The defect inspection device 1 extracts a defect by receiving an image of the reflected light of the light of the object 2 to be inspected from the visible light source 31 and the IR/UV light source 32 by the visible light camera 41 and the IR/UV light camera 42. Further, the type of the defect is determined. The defect inspection device 1 can detect foreign matter, holes, wrinkles, mottles, and the like as defects.

Further, in the case where the visible light source 31 and the IR/UV light source 32 are not distinguished, it is simply referred to as "light source 3". Further, the case where the visible light camera 41 and the IR/UV light camera 42 are not distinguished is referred to simply as "camera 4". The light source 3 can be limited to a wavelength region using an LED or the like, or a wavelength filter can be used to limit the wavelength region. Moreover, by using a wavelength that is more remarkable in interaction with the substance, the accuracy of the detection of the defect or the type of the defect is improved. Further, in the present embodiment, the visible light source 31 is equivalent to the IR/UV light source 32. In the irradiation unit of the present invention. Further, in the present embodiment, light is irradiated onto the test object 2 by the visible light source 31 and the IR/UV light source 32, which corresponds to the irradiation step of the present invention.

The camera 4 is configured to include, for example, a CCD image sensor in which 4096 light receiving elements are arranged in series. In each of the light receiving elements, light is converted into electric charges in accordance with the amount of received light. Therefore, the light receiving element at the position where the light reflected by the defect is imaged has a smaller amount of charge than the other light receiving elements. Further, in the present embodiment, the visible light camera 41 includes three CCD image sensors for each of the components R, G, and B. Further, the IR/UV optical camera 42 includes a CCD image sensor that detects at least one of ultraviolet light and infrared light. The electric charge output from each light receiving element is input to the processing device 5 as imaging data. Further, in the present embodiment, the visible light camera 41 and the IR/UV optical camera 42 correspond to the data generating unit of the present invention. Further, in the present embodiment, the image data is generated by the visible light camera 41 and the IR/UV light camera 42, which corresponds to the data generating step of the present invention.

Further, in the present embodiment, in order to capture the entire width of the inspection object 2 by the camera 4, a plurality of cameras 4 can be provided in the width direction of the inspection object 2 in accordance with the width of the inspection object 2. Further, the visible light camera 41 and the IR/UV optical camera 42 are arranged to be shifted in the conveyance direction.

Further, the processing device 5 includes an R signal processing unit 51, a G signal processing unit 52, a B signal processing unit 53, and processing for processing the imaging data output from the visible light camera 41 for each of the components R, G, and B. The IR/UV signal processing unit 54 of the imaging data output from the IR/UV optical camera 42. The R signal processing unit 51 processes the signal (R signal) of the R component, and the G signal processing unit 52 processes the signal (G signal) of the G component, and the B signal processing unit 53 The signal of the component B (B signal) is processed, and the IR/UV signal processing unit 54 processes a signal (IR/UV light signal) of ultraviolet light or infrared light. By this processing, the reflectance of each light receiving element (pixel) is obtained.

Here, the reflectance is a value obtained by dividing the electric charge (imaging material) of each of the light receiving elements by the electric charge (imaging material) of each of the light receiving elements when the defect is obtained in advance. In other words, the image data of the object 2 to be inspected without defects is obtained in advance, and the ratio of the image data at the time of the defect determination to the value is set as the reflectance. The "charge of each light-receiving element when there is no defect in advance" may be an average value of charges of the respective light-receiving elements when performing plural imaging. The larger the degree of decrease in the amount of received light, the smaller the value becomes, and the correlation with the degree of change in the image data. Moreover, in the case of no defect, the reflectance becomes a value close to 1. The respective reflectances were calculated for the R signal, the G signal, the B signal, and the IR/UV optical signal. Further, in the present embodiment, the reflectance corresponds to the division value of the present invention.

Here, Fig. 2 is a view showing the relationship between the pixel and the reflectance after the processing by each of the signal processing units 51, 52, 53, and 54. The horizontal axis is a pixel, and the vertical axis is a reflection ratio. At the pixel where the defect is imaged, the reflectance is reduced. Moreover, the degree of reduction is different for each of the R signal, the G signal, the B signal, and the IR/UV optical signal. Further, even in the case where there is no defect in the test object 2, the reflection plate is slightly different in each pixel due to the influence of the unevenness or the like on the surface of the test object 2.

Further, the processing device 5 includes a position alignment processing unit 55 that aligns the reflectance obtained from the visible light camera 41 with the reflectance obtained from the IR/UV optical camera 42. Here, since the visible light camera 41 and the IR/UV light camera 42 are configured to be in the object 2 to be inspected Since the conveyance direction is shifted, it takes time to reach the position photographed by the IR/UV light camera 42 at the position where the visible light camera 41 is photographed. In order to compare the reflectances from the same position obtained by the visible light camera 41 and the IR/UV light camera 42, the alignment processing unit 55 performs the alignment of the reflectance of the visible light camera 41 with the reflectance of the IR/UV light camera 42.

Here, since the conveyance speed of the inspection 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 position captured by the visible light camera 41 can be calculated to be IR/UV light. The time taken by the camera 42 is delayed. That is, the alignment can be performed by shifting the data only by the amount of time delay. Similarly, when the other positions are taken by the R signal, the G signal, and the B signal, or when the other positions are captured by the ultraviolet light and the infrared light, the alignment is performed.

Further, the processing device 5 includes a defect detecting unit 56 that detects a defect, and a detection threshold memory unit 56A that is a threshold value for the size of the memory defect. The threshold value is previously memorized as a lower limit value that needs to be detected as the size of the defect, and is memorized in advance. The threshold value is determined according to the type of the object 2 to be inspected, the needs of the user, and the like.

In addition, there are cases where the defect is small even if there is a defect. The size of the defect when the allowable range is exceeded is set as the threshold. In other words, the defect detecting unit 56 determines that the defect exists when the size of the defect is equal to or greater than the threshold value, and determines that there is no defect when the size of the defect is less than the threshold value. The size of the defect is represented by the amount of decrease in reflectance or the number of pixels in which the reflectance is reduced. For example, the size of the defect can be found from the waveform shown in Fig. 2. In addition, it may be detected as a defect when some of the reflectance is below the threshold. Also It can be detected as a defect when some of the pixels whose reflectance is below the threshold are above the threshold.

Further, the processing device 5 includes a determination unit 57 that discriminates the type of the defect when the defect is detected, and a determination threshold storage unit 57A that stores the threshold value for determining the type of the defect. The determination unit 57 determines the type of the defect based on the relationship between the pixel processed by each of the signal processing units 51, 52, 53, and 54 and the reflectance. Then, the type of presence or absence of defects and defects is output from the output unit 58. Further, in the present embodiment, the determination unit 57 determines the type of the defect, which corresponds to the determination step of the present invention.

Here, Fig. 3 is a view in which the signals shown in Fig. 2 are superimposed. In this way, the degree to which the reflectance of each signal decreases is different. Further, the degree to which the reflectance of each signal is lowered is a value unique to each substance. Here, for example, the wavelength of the ultraviolet light is easily absorbed by the substance because it is close to the bond energy of the molecule or the atom. Moreover, since the wavelength of the ultraviolet light is relatively short, it is easy to scatter. On the other hand, the wavelength of infrared light is easily absorbed by the substance because it is close to the vibrational energy of the molecule. Moreover, since the wavelength of the infrared light is relatively long, it is difficult to scatter. By using the interaction of light and matter at these wavelengths, the type of defect can be discriminated.

For example, Figure 4 is a graph showing the relationship between the pixel and the reflectance when the defect is water. The reflectance of the pixel imaged by the defect is lower than that of other pixels, but the amount of reduction (which can also be regarded as the rate of decrease) is due to visible light and infrared light or ultraviolet light (hereinafter also referred to as IR/UV light). different. Therefore, in the pixel imaged by water, the reflectance in visible light is inferior to the reflectance of infrared light (IR light).

This visible light reflectance is unique to the difference between the reflectance of IR/UV light. In other words, when the visible light and the IR/UV light are respectively irradiated to the substance, since the absorption rate of each light varies depending on each substance, the ratio of each light to be reflected by the substance and the ratio of each light-transmitting substance vary depending on the respective substances. Therefore, the value of the reflectance of visible light and IR/UV light in the pixel imaged by the defect is due to the substance forming the defect.

Therefore, if the difference between the reflectance of the visible light and the reflectance of the IR/UV light is obtained for each of the substances that may be mixed by an experiment or calculation, the type of the defect can be determined based on the difference in the reflectance.

Further, Fig. 5 is a view showing the relationship between the pixel and the reflectance when the defect is metal. In the case where the defect is a metal, since the reflectance of visible light is almost the same as the reflectance of IR/UV light, the difference between the two reflectances is small. Therefore, in the case where the difference between the reflectance of visible light and the reflectance of IR/UV light (which may also be the absolute value of the difference) is equal to or less than the threshold value, it is possible to discriminate that the defect is a metal. The threshold can be obtained by experiments or the like in advance. Further, since the reflectance changes depending on the type of the metal, the type of the metal can be determined based on the reflectance. For example, in the case where the test object 2 is an electrically insulating sheet, even if there is dirt, there is no problem as long as the electrical conduction can be blocked. However, when the metal is mixed into the sheet, it is electrically conductive, which is problematic. Therefore, as long as it is possible to discriminate whether or not the defect is a metal, dirt can be allowed, and only the metal can be detected as a defect.

In this way, the type of defect can be determined in response to the difference between the reflectance of visible light and the reflectance of IR/UV light. Here, by using the difference in reflectance, the influence of the state of the object 2 or the defect or the influence of the variation in the amount of light can be made small. For example, the amount of light received by the light-receiving element may be The color of the object 2 or the color of the defect changes. Further, as long as the amount of light varies, the amount of light received by the light-receiving element also changes, so that the reflectance does not change even if there is no defect. In this way, the reflectance of visible light and IR/UV light changes even without defects. In contrast, by taking the difference between the reflectance of visible light and the reflectance of IR/UV light, the amount of change in the amount of light received by each light-receiving element due to fluctuations in the amount of light or the like can be eliminated. In other words, since the influence of the state of the color or surface of the test object 2 and the influence of the fluctuation of the light amount can be reduced, the accuracy of detecting the defect and the accuracy of determining the type of the defect can be improved.

Further, the difference between the reflectance of visible light and the reflectance of IR/UV light may be used instead of the difference between the two to determine the type of the defect.

Further, in the visible light system, only one of the R component, the G component, and the B component may be used to determine the type of the defect. Further, one or both of infrared light or ultraviolet light may be used to determine the type of the defect. Further, when one of the R component, the G component, and the B component is selected and one of infrared light or ultraviolet light is selected, a combination in which the difference in wavelength is large may be selected. For example, when combined with ultraviolet light having a short wavelength, an R component having a long wavelength in visible light is used, and when combined with a long-wavelength infrared light, a B component having a short wavelength in visible light is used. Thereby, since the difference in the reflectance of the defect is more prominent, the determination accuracy can be improved.

Further, a Si (tantalum)-based semiconductor can be used as the light receiving element of the camera 4. When a Si-based semiconductor light-receiving element is used, ultraviolet light, visible light, and infrared light can be detected. Moreover, it can be multi-pixelized, and can perform measurement in a wide range or high speed, and can also be low in cost.

Next, Fig. 6 is a flow chart showing the flow of discriminating the kind of the defect of the embodiment.

In step S101, the object 2 is photographed by the camera 4, and the data is taken into the processing device 5.

In step S102, the signals output from the camera 4 are processed by 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, respectively. Further, each signal processing unit calculates a reflection ratio for each pixel.

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

In step S104, the defect detection unit 56 performs detection of the defect. For example, when the size of the defect is equal to or greater than the threshold value stored in the detection threshold storage unit 56A, the defect detecting unit 56 detects the defect as a defect. Further, for example, when some of the reflectances are below the threshold value stored by the detection threshold storage unit 56A, it may be detected as a defect.

In step S105, it is determined whether or not a defect is detected in step S104. If the result of the determination in step S105 is affirmative, the process proceeds to step S106. On the other hand, if the result of the determination in step S105 is negative, it is regarded as no defect, and the flow is ended.

In step S106, the borrowing unit 57 determines the type of the defect. The determination unit 57 distinguishes the type of the defect by comparing the difference between the reflectance of the visible light and the reflectance of the IR/UV light and the threshold value stored in the determination threshold storage unit 57A. For example, when the difference between the reflectance of visible light and the reflectance of IR/UV light is equal to or less than the threshold value, it is determined that the defect is a metal. Then, based on the reflectance of each metal that is memorized in advance, the type of the metal is discriminated, and, for example, since water absorbs infrared light more easily than oil, visible light is utilized. The difference between the reflectance of the component B and the reflectance of the infrared light is relatively large, and oil and water can be discriminated. Further, the determination threshold storage unit 57A may store the difference between the reflectance of the visible light and the IR/UV light and the substance in advance, and lock the substance based on the relationship.

In step S107, the type of the defect and the defect detected is output from the output unit 58. At this time, for example, a defective image can also be output. Further, it is also possible to memorize the location of the defect and the type of the defect, or to add a mark to the position where the defect exists. Further, an alarm may be issued when the defect is present, or the presence of the defect or the type of the defect may be displayed on the display. Further, if the type of the defect determined in step S106 is acceptable, the output is free from defects.

As described above, according to the present embodiment, the defect of the inspection object 2 can be detected, and the type of the defect can be discriminated. Moreover, the interaction with the substance caused by infrared light or ultraviolet light can be utilized to detect defects that cannot be detected by visible light alone. Further, by using the invisible light in combination, it is possible to discriminate the type of defect in which the color is similar to that of the light projecting element 2 and is determined only by visible light. Further, by using a Si-based semiconductor light-receiving element, ultraviolet light, visible light, and infrared light can be detected. Moreover, it can be multi-pixelized, and can perform measurement in a wide range or high speed, and can also be low in cost. Further, by calculating the reflectance based on the normal position, by comparing the reflectance with visible light and IR/UV light, it is possible to reduce the error caused by the variation in the amount of light or the difference in the reflectance of each defect. Therefore, it is not susceptible to the state of disturbance or defects.

(Second embodiment)

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

In the present embodiment, the detection of defects and the determination of the type of defects are performed based on the transmittance of visible light, infrared light, or ultraviolet light in the test object 2. Here, the charge ratio (imaging material) of each light-receiving element is divided by the value of the electric charge (imaging material) of each light-receiving element when the defect is obtained in advance. In other words, the image data of the inspection object 2 without defects is obtained in advance, and the ratio of the image data at the time of defect determination to the value is used as the transmission ratio. The "charge of each light-receiving element when there is no defect in advance" may be an average value of the charges of the respective light-receiving elements when the image is taken a plurality of times. The greater the degree of decrease in the amount of received light, the smaller the transmission ratio is, and the correlation with the degree of change in the image data. Moreover, in the case of no defect, the transmission ratio becomes a value close to 1. The respective transmittances were calculated for the R signal, the G signal, the B signal, and the IR/UV optical signal. Further, in the present embodiment, the transmission ratio corresponds to the division value of the present invention.

The transmittance of visible light, ultraviolet light, and infrared light is the same as the reflectance described in the first embodiment, and varies depending on each substance. Therefore, the pixel at the position where the defect is imaged is inferior in the transmittance ratio due to visible light and IR/UV light. This difference is a value unique to the substance. That is, when the visible light and the IR/UV light are irradiated to the substance, since the light absorption rate of each of the substances varies depending on each substance, the ratio of each light-transmitting substance varies depending on each substance.

Therefore, if the difference between the transmittance of visible light and the transmittance of IR/UV light is obtained by experiments or calculations for each substance that may be mixed in advance, The type of the defect can be determined based on the difference in the transmittance.

Further, depending on the type of the object to be inspected 2 or the type of the substance to be mixed, it is also possible to determine which type of defect is to be determined depending on which of the transmittance ratio or the reflection ratio. For example, it is also possible to find out which one is more suitable by experiment or the like. Further, for example, a transmission ratio may be used when the inspection object 2 is thin, and a reflection ratio may be used when the inspection object 2 is thick, depending on the thickness of the inspection object 2, and translucent light may be used. And both sides of the reflected light.

(Third embodiment)

Fig. 8 is a block diagram of the defect inspection apparatus 1 of the third embodiment. In the present embodiment, only one camera 4 is provided. The one camera 4 has both the visible light camera 41 and the IR/UV light camera 42 of the first embodiment. That is, the camera 4 of the present embodiment includes a light receiving element that measures at least one of R, G, and B, and a light receiving element that measures at least one of infrared light and ultraviolet light. Further, the visible light source 31 and the IR/UV light source 32 illuminate the same position. Since other devices and the like are the same as those of the first embodiment, the description thereof is omitted.

Here, Fig. 9 is a view showing the configuration of the sensor. R is a sensor that detects the R component in visible light, G is a sensor that detects the G component in visible light, B is a sensor that detects the B component in visible light, and IR/UV detects infrared. Light or ultraviolet sensor. Each of the R, G, B, and IR/UV sensors is configured to be staggered in the direction of transport. Therefore, as in the first embodiment, it is necessary to align the positions of the output signals of the respective sensors. By using such a camera 4, the device can be miniaturized.

(Fourth embodiment)

Fig. 10 is a block diagram of the defect inspection apparatus 1 of the present embodiment. also, Fig. 11 is a view showing the internal structure of the camera 4. R is a sensor that detects the R component in visible light, G is a sensor that detects the G component in visible light, B is a sensor that detects the B component in visible light, and IR/UV detects infrared. Light or ultraviolet sensor. This embodiment is the same as the third embodiment except that one camera 4 is provided. However, the spectroscopic element 43 is used to separate visible light and IR/UV light, and is measured by each light-receiving element. This is in contrast to the third embodiment. different.

In other words, in the present embodiment, since the light beams traveling in the same direction are split by the spectroscopic element 43 and then received by the respective sensors, the visible light reflected from the same position of the object 2 can be imaged by one camera 4. And IR/UV light. Moreover, since the same position of the data can be obtained at the same time, no alignment is required. Therefore, the alignment processing unit 55 required in the first to third embodiments is not required. Since other devices and the like are the same as those of the third embodiment, the description thereof is omitted.

By using such a camera 4, since the alignment is not required, the processing can be simplified. Moreover, it is not affected by the accuracy of the positional alignment.

1‧‧‧ Defect inspection device

2‧‧‧Inspected objects

5‧‧‧Processing device

31‧‧‧ Visible light source

32‧‧‧IR/UV light source

41‧‧‧ Visible light camera

42‧‧‧IR/UV light camera

51‧‧‧R Signal Processing Department

52‧‧‧G Signal Processing Department

53‧‧‧B Signal Processing Department

54‧‧‧IR/UV Signal Processing Department

55‧‧‧ Position Alignment Processing Department

56‧‧‧Defect Detection Department

56A‧‧‧Detection threshold memory

57‧‧‧Decision Department

57A‧‧‧Determined Threshold Memory

58‧‧‧Output Department

Claims (12)

A defect inspection method is a defect inspection method for inspecting a defect of an inspection object by using the conveyed sheet-like article as an inspection object, comprising: an irradiation step of irradiating the inspection object with visible light and infrared light from a light source; a step of respectively receiving visible light and infrared light reflected by the object to be inspected, and respectively generating image data corresponding to each light receiving amount; and a defect detecting step of at least any of the image data of visible light and the image data of infrared light Compared with the defect-free state, the region in which the change is detected is regarded as a defect; and the determination step is related to the defect detected in the defect detecting step, when the degree of change in the image data of the visible light is the same as the degree of variation of the image data of the infrared light. The type of the defect is determined to be a defect in which metal adheres or metal is mixed. The defect inspection method according to the first aspect of the invention, wherein in the determining step, the difference between the degree of change in the image data of visible light and the degree of fluctuation of the image data of the infrared light is less than a threshold value, and is determined as The degree of variation of the image data of the visible light is the same as the degree of variation of the image data of the infrared light. The defect inspection method of claim 1 or 2, wherein in the defect detection step, when the magnitude of the change in the image data is greater than or equal to a predetermined value, it is determined that the image data is compared to the defect-free state. changing. For example, in the defect inspection method of claim 1 or 2, in the determining step, based on the degree of change of the image data, The type of metal that is not attached or mixed. For example, in the defect inspection method of claim 1 or 2, wherein the division value is used in the degree of variation of the image data, the division value is the image data generated in the data generation step divided by the pre-image-free defect The value obtained by the camera data of the object to be inspected. The defect inspection method according to claim 1 or 2, wherein the object to be inspected is a paper, a film, a resin, a cellulose, a separator used for a secondary battery, or an optical sheet. The defect inspection method according to claim 1 or 2, wherein the Si-based semiconductor light-receiving element receives visible light and infrared light, respectively. For example, in the defect inspection method of claim 1 or 2, wherein one camera separately has components for receiving visible light and infrared light. The defect inspection method according to claim 1 or 2, wherein the visible light and the infrared light are split by the light splitting element, and the visible light and the infrared light are respectively received. A defect inspection method according to claim 1 or 2, wherein the light source is a light source having a wavelength-limited region. The defect inspection method of claim 1 or 2, wherein the light irradiated from the light source is passed through a wavelength filter to limit the wavelength region. A defect inspection device is a defect inspection device that inspects a defect of an inspection object by using the conveyed sheet-like article as an inspection object, and includes an irradiation portion that irradiates the inspection object with visible light and infrared light from a light source; The data generating unit receives the visible light and the infrared light reflected by the inspection object, and generates imaging data corresponding to each of the received light amounts; and the defect detecting unit is at least one of the image data of the visible light and the image data of the infrared light. The detection region is detected as a defect as compared with the defect-free state, and the determination unit detects the defect detected by the defect detection unit, and the degree of fluctuation of the image data in visible light is the same as the degree of variation of the image data of the infrared light. At the time, the type of the defect was judged to be a defect in which metal was adhered or mixed.