JP2013231662A - Method for inspecting laminate, method for manufacturing laminate, and apparatus for inspecting laminate - Google Patents

Abstract

Provided is a method for inspecting a laminate that can detect a plurality of types of defects in a well-balanced manner and can simplify the apparatus configuration.
An inspection of a laminate in which a system having at least a light transmission layer (102, 102 ') and a light reflection surface (101a) on a light path is irradiated with light, and the reflected light is received to detect a defect. Method (S1), a step of irradiating the laminate with light using a plurality of types of light sources (110, 120) having peak values at wavelengths having different transmittances based on the light transmittance characteristics of the light transmissive layer. (S21), a step (S22) of receiving reflected light from the laminated body of the irradiated light by the detector (130), and a step of performing image processing based on the received information to detect a defect (S23). And comprising.
[Selection] Figure 1

Description

  The present invention relates to a method for inspecting a defect in a laminate in which a plurality of layers are laminated, a method for producing a laminate using the method, and an inspection apparatus for the laminate.

  An electrophotographic photosensitive member provided in an image forming apparatus such as a laser printer, an organic thin-film solar cell used for solar power generation, and the like transmit a layer that reflects light and a light that is stacked on the layer that reflects the light. A laminated body having a layer. In order to inspect the quality of such a laminated body, a method of irradiating light from a light source and receiving the reflected light by a detector and analyzing an image is employed.

  The defects to be detected in the quality inspection are not necessarily one type such as minute unevenness (roughness), film thickness unevenness, foreign matter existing between layers, and these multiple types of defects are all balanced. Need to detect well. Moreover, it is necessary to suppress a decrease in inspection accuracy due to so-called noise. However, when predetermined light is applied to the laminate, some defects have good detection sensitivity, but other defects may have poor detection sensitivity.

  For example, Patent Literature 1 discloses a technique for selecting and irradiating a wavelength at which an image that does not cause film thickness unevenness even with a subtle film thickness difference is obtained. According to this, simulation of reflection characteristics including diffraction of the laminate as the subject is performed, and the wavelength of the light source determined to be appropriate from the result is selected.

  Patent Document 2 describes that for the purpose of high-precision inspection, it is possible to eliminate the need to provide a plurality of inspection stages by sequentially irradiating a plurality of monochromatic lights.

JP 2009-85826 A JP 2012-26862 A

However, in the invention described in Patent Document 1, it is necessary to construct a relatively large system because a means for selecting a wavelength using simulation and obtaining light of a wavelength corresponding to this is required.
Also, since the appropriate wavelength is determined by simulation, the appropriate wavelength varies depending on the subject (layer composition and layer thickness), and the wavelength may differ even when the subject is similar. The wavelength had to be changed, and many types of light sources used for inspection had to be prepared.
Furthermore, since the selection of the wavelength is determined by simulation, there is a risk of errors.

  Regarding the invention described in Patent Document 2, as in Patent Document 1, it is necessary to prepare many illumination lights having different colors (wavelengths) according to the type of the subject, so the apparatus is large and It becomes complicated.

  Therefore, in view of the above problems, an object of the present invention is to provide a laminate inspection method that can detect a plurality of types of defects in a well-balanced manner and can simplify the apparatus configuration. Moreover, the manufacturing method of a laminated body including this test | inspection method and a test | inspection apparatus are provided.

As a result of intensive studies, the inventor has obtained the following knowledge by paying attention to the fact that the light transmission layer included in the laminate has a property that the transmittance varies depending on the wavelength.
Since a light source having a wavelength with a high transmittance of the light transmission layer is used, a lot of light is reflected by the light reflection surface on which the light transmission layer is laminated, and the reflected light from the light reflection layer is reflected from the surface of the light transmission layer. When it is relatively large with respect to light, the sensitivity to detect foreign matter is increased, but noise is also increased and the S / N ratio is deteriorated, so that it has been found that unevenness tends not to be detected. Therefore, according to this, the foreign object detection accuracy is high, but the size of the reflected light from the light reflecting layer changes depending on the type (due to the difference in the transmission characteristics of the light transmitting layer). When irradiated, there is a possibility that a highly reliable inspection cannot be performed.

  On the other hand, if a light source having a wavelength with a low transmittance of the light transmission layer is used, if the light reflected on the surface of the light transmission layer is relatively larger than the light reflected on the light reflection surface, the detection sensitivity of unevenness is reversed. Increases and noise is reduced, but it is difficult to detect foreign matter. Therefore, according to this, although the detection sensitivity of unevenness is high, the size of the surface reflected light of the light transmission layer changes depending on the type (due to the difference in the transmission characteristics of the light transmission layer), and the same light source is used for different types. When irradiated, a reliable test cannot be performed.

  However, if two light sources are separately provided and an inspection system is constructed for each, the inspection system becomes large. Furthermore, since the positions where the two inspection systems irradiate light are different, for example, it is difficult to grasp the relative positional relationship between the unevenness detection location and the foreign matter detection location, and it is difficult to find the cause of the defect. There is.

  Based on the above knowledge, the inventor has further developed this, and simultaneously irradiates light having a plurality of wavelengths, that is, a light having a high light transmittance and a light having a low light transmittance. Thus, the present invention has been completed by obtaining the knowledge that a plurality of types of defects can be detected in a balanced manner. The present invention will be described below. For ease of understanding, reference numerals in the drawings are described in parentheses, but the present invention is not limited to this.

  According to the first aspect of the present invention, light is irradiated onto a system having at least a light transmission layer (102, 102 ') and a light reflection surface (101a) on the optical path, and the reflected light is received to detect a defect. In the method for inspecting a laminate (S1), a plurality of types of light sources (110, 120) having peak values at wavelengths with different transmittances are used on the laminate based on the light transmittance characteristics of the light transmissive layer. A step of irradiating light (S21), a step of receiving reflected light from the laminated body of irradiated light by a detector (130), and performing image processing based on the received information to detect defects. And a step (S23) of performing a laminated body inspection method.

  The invention according to claim 2 is the method for inspecting a laminate (S1) according to claim 1, wherein before the step (S21) of irradiating the laminate (100, 100 ′) with light, the light transmission layer ( 102, 102 ′), and a step (S12) of selecting a plurality of types of light sources (110, 120) having peak values at wavelengths having different transmittances.

  The invention according to claim 3 is the method for inspecting a laminate according to claim 2 (S1), after the step of selecting a light source (S12) and before the step of irradiating the laminate with light (S21). In addition, there is a step (S13) of determining a mixing ratio of irradiation of the selected plural types of light sources (110, 120).

  According to a fourth aspect of the present invention, in the laminate inspection method (S1) according to any one of the first to third aspects, the detector (130) is a monochrome sensor.

  A fifth aspect of the present invention is the method for inspecting a laminate according to any one of the first to fourth aspects (S1), wherein the peak values of wavelengths of the plurality of types of light sources (110, 120) are detected by a detector (130). Is selected from the detectable wavelength region.

  A sixth aspect of the present invention is the laminate inspection method (S1) according to any one of the first to fifth aspects, wherein the light sources (110, 120) are LEDs.

  A seventh aspect of the present invention is the method for inspecting a laminate according to any one of the first to sixth aspects (S1), wherein the light source (110, 120) can change the output intensity for each of a plurality of types. is there.

  The invention according to claim 8 is the laminate inspection method (S1) according to any one of claims 1 to 7, wherein the laminate (100, 100 ') is an electrophotographic photosensitive member.

  Invention of Claim 9 has a process which laminates | stacks a light transmissive layer on the member used as a light reflection surface, produces laminated body (100,100 '), and it is intended for the produced laminated body. It is a manufacturing method of a laminated body including the process of detecting a defect with the inspection method (S1) of the laminated body in any one of 1-8.

  The invention according to claim 10 is an inspection apparatus for a laminate, and based on the light transmittance characteristics of the light transmission layer of the laminate, a plurality of types of light sources (110, 120) having peak values at wavelengths having different transmittances. ), A detector (130) that receives the reflected light from the stack of light emitted from the light source, and an image processing device (140) that performs image processing based on the received information and detects defects It is the inspection apparatus of a laminated body provided.

  According to the present invention, it is possible to detect a plurality of types of defects in a balanced manner. At that time, it is not necessary to perform a simulation to set the examination conditions, and even if the subject type is changed, the necessity of changing the light source can be reduced and the output intensity of each light source can be adjusted. Since only setting is possible, the configuration of the apparatus can be simplified and the inspection setting can be facilitated.

It is a figure which shows the flow of inspection method S1 of the laminated body concerning one Embodiment. It is a figure which shows the flow of condition setting process S10 among the inspection methods S1 of a laminated body. It is a figure which shows the flow of inspection process S20 among the inspection methods S1 of a laminated body. It is a figure which represents typically the structure of the inspection apparatus of a laminated body. It is a figure explaining the other example of a laminated body. It is a figure explaining the transmittance | permeability characteristic of a light transmissive layer. FIG. 6A shows the light transmission layer 102, and FIG. 6B shows the light transmission layer 102 '. It is a figure explaining reflection of light. FIG. 7A shows an example of this embodiment, and FIG. 7B shows a comparative example. It is a figure explaining reflection of light. FIG. 7A shows an example of this embodiment, and FIG. 7B shows a comparative example.

  The above-described operation and gain of the present invention will be clarified from embodiments for carrying out the invention described below. Hereinafter, the present invention will be described based on embodiments shown in the drawings. However, the present invention is not limited to these embodiments. In the drawings used for explanation, exaggeration and conceptual description are included for easy understanding.

  FIG. 1 is a diagram for explaining one embodiment, and is a diagram showing the flow of a laminate inspection method S1. FIG. 4 is a view conceptually showing the arrangement of the laminate inspection apparatus used in the laminate inspection method S1 and the electrophotographic photosensitive member which is a laminate as a subject. In this embodiment, a method for inspecting a laminated body formed on the outer peripheral portion of an electrophotographic photosensitive member will be described as an example. However, the present invention is not limited to the subject having a tubular shape, and can be applied to a strip or a single wafer. The subject of the present invention is not limited to an electrophotographic photosensitive member, and may be any system as long as it has a system having a light reflecting surface disposed on an optical path and a light transmitting layer laminated thereon. For example, an organic thin film solar cell, organic EL, etc. are mentioned.

The laminated body inspection method S1 includes a condition setting step S10 and an inspection step S20. FIG. 1 shows the flow of the laminate inspection method S1.
The condition setting step S10 is a step of determining the type of light source (type of wavelength) and the intensity of each light source in advance when performing the inspection step S20. Accordingly, once the condition setting step S10 is determined, it is not always necessary to perform the condition setting step S10 every time the inspection step S20 is performed, and can be omitted. FIG. 2 shows the flow of the condition setting step S10. The condition setting step S10 includes a transmittance characteristic acquisition step S11, a light source selection (wavelength selection) step S12, and a mixing ratio determination step S13 for each wavelength.
On the other hand, the inspection step S20 is a step of actually inspecting the subject based on the conditions obtained in the condition setting step S10. FIG. 3 shows the flow of the inspection step S20. The inspection step S20 includes a light irradiation step S21, a reflected light receiving step S22, and an image analysis step S23.
Each step will be described below.

The transmittance characteristic acquisition step S11 is a step of acquiring the characteristics of the light transmission layer, which is a layer that transmits light, of the laminate 100 (see FIG. 4) that is the subject in the present embodiment. Details are as follows. The laminate 100 that is the subject of the present embodiment transmits at least a light reflection layer 101 (see FIG. 7) including a light reflection surface 101a that is a layer that reflects light, and light stacked on the light reflection surface 101a. The light-transmitting layer 102 is a layer.
The light reflecting layer 101 is a layer made of a metal such as aluminum, for example, and has a property that the light reflecting surface 101a which is the surface thereof reflects light.
On the other hand, the light transmission layer 102 is a layer that is laminated on the light reflection surface 101a and has a property of transmitting light. Furthermore, as shown in the graph of FIG. 6A, the light transmission layer 102 has the property that the light transmittance varies depending on the wavelength of the irradiated light. The graph of FIG. 6A is a graph in which the wavelength (nm) of light irradiated on the horizontal axis and the transmittance on the vertical axis. In this embodiment, light having a short wavelength is easily transmitted, and light having a long wavelength is difficult to transmit.

  The light reflecting layer 101 and the light transmitting layer 102 can be appropriately set depending on the type of the laminated body. In this embodiment, the electrophotographic photosensitive member is used as the specimen as the laminated body 100. The electrophotographic photoreceptor is constituted by laminating UCL (blocking layer), CGL (charge generation layer), and CTL (charge transport layer) in this order on the surface of an aluminum substrate. Therefore, in this embodiment, the light reflection layer 101 is an aluminum base, and the light transmission layer 102 is at least one of UCL, CGL, and CTL. In the present invention, when the light transmission layer is formed of a plurality of layers, light from a light source described later reaches the layer to be inspected among the plurality of layers, and the inspection is performed. It goes without saying that the conditions of the light from the light source described later should be satisfied for all the layers to be subjected to the above.

  In the present embodiment, an example in which the light reflection layer and the light transmission layer are integrally formed will be described. However, the light reflection layer and the light transmission layer are separate from each other without being limited thereto, and at least a part thereof. If a system in which a light transmission layer is laminated on the light reflection surface is formed, a laminate can be obtained. FIG. 5 shows a laminate 200 as another example. According to this, the laminated body 200 can be formed by placing a sheet-like workpiece including the light transmission layer 202 on a roll having a high light reflectance that forms the light reflection layer 201 including the light reflection surface 201a. it can. Such a laminate may be used.

  In FIG. 6B, the light transmission characteristics (indicated by a one-dot chain line) of the light transmission layer 102 ′ according to another type of example are shown together with the light transmission characteristics (indicated by a solid line) of the light transmission layer 102. . The light transmissive layer 102 ′ has a property that light having a short wavelength is difficult to transmit and light having a long wavelength is easily transmitted.

  In the method for inspecting a laminate according to the present invention, the light transmission layer has the property that the transmittance varies depending on the wavelength.

  In such transmittance characteristics, it is only necessary to clarify a wavelength with a high transmittance and a wavelength with a transmittance lower than this, and an absolute value of the transmittance is not necessarily required. Therefore, when obtaining the transmittance characteristics, it is not necessary to measure the transmittance by making the film thickness the same as that of the light transmissive layer of the laminate, and simply measure the transmittance for each wavelength with a specimen having an arbitrary thickness. It is possible. A specific method for measuring the transmittance is not particularly limited, and examples thereof include the following two methods.

One method is a method of measuring a coating solution, and the coating solution is measured using a generally known spectrophotometer (absorption spectrophotometer, for example, UV-visible spectrophotometer, UV-1650PC manufactured by Shimadzu Corporation).
Conditions such as cell size and sample concentration when measuring light transmittance vary depending on physical properties such as refractive index. Therefore, the measurement limit of the detector is usually limited in the wavelength region to be measured (for example, 400 nm to 1000 nm). Adjust the sample concentration appropriately so that it does not exceed. The solvent used to adjust the sample concentration is usually the solvent used as the solvent for the light-transmitting layer forming coating solution, but is compatible with the solvent for the light-transmitting layer forming coating solution and the binder resin. Any mixture can be used as long as it does not cause turbidity when mixed and does not have large light absorption in the wavelength region of 400 nm to 1000 nm.
Moreover, it is preferable that the cell size (optical path length) at the time of measurement is 10 mm. Any cell may be used as long as it is substantially transparent in the wavelength region of 400 nm to 1000 nm. However, it is preferable to use a quartz cell, in particular, a sample cell and a standard cell. It is preferable to use a matched cell that has a difference in transmittance characteristics within a specific range.

  The other method is a method in which the applied material is peeled off and measured, and the light transmission layer (for example, the charge generation layer) is dispersed in a solvent capable of dissolving the binder resin binding the light transmission layer. When the dispersion liquid is obtained, the light transmittance of the dispersion liquid exhibits specific physical properties. The light transmittance in this case can also be measured in the same manner as in the case of measuring the light transmittance of the coating liquid for forming a light transmissive layer of the electrophotographic photosensitive member. When the light transmissive layer is dispersed to form a dispersion, the binder resin that binds the light transmissive layer is not substantially dissolved, and is formed on the light transmissive layer (for example, a charge transport layer). It is possible to obtain a dispersion by dissolving and removing the layer on the light transmission layer with a solvent capable of dissolving the resin, and then dissolving the binder resin binding the light transmission layer in the solvent. As a solvent in this case, a solvent that does not have large light absorption in the wavelength region of 400 nm to 1000 nm may be used.

  The light source selection (wavelength selection) step S12 is a step of selecting at least two types of light sources based on the transmittance characteristics of the light transmission layer 102 acquired in the transmittance characteristic acquisition step S11. These two types of light sources are the first light source 110 and the second light source 120 shown in FIGS. In other words, in the present embodiment, the first light source 110 is a light source that emits light having a peak value of a short wavelength wavelength that is a high transmittance among the light transmission characteristics of the light transmission layer 102. On the other hand, in the present embodiment, the second light source 120 is a light source that emits light having a peak wavelength of a wavelength on the long wavelength side, which is a transmittance lower than the high transmittance, among the light transmission characteristics of the light transmission layer 102. is there.

  Thus, the first light source and the second light source select each of at least two wavelengths having different transmittances based on the light transmittance characteristics of the light transmissive layer of the laminate that is the subject, and each of the selected light sources. Any light source can be used as long as it can emit with the wavelength as a peak wavelength. Therefore, it is not always necessary that the first light source has a wavelength with a high transmittance, and the second light source has a wavelength with a low transmittance. For example, for the light transmissive layer 102 ′ shown in FIG. 6B, the first light source 110 is a light source that can emit a wavelength having a low transmittance as a peak wavelength, and the second light source 120 has a high transmittance. It functions as a light source that can emit a wavelength as a peak wavelength, and may be in such a mode.

  The selection of the first light source and the second light source only needs to be based on the light transmission characteristics as described above, and particularly how far the peak wavelength of the first light source and the peak wavelength of the second light source are different. There is no limit. Therefore, for example, as shown in FIG. 6B, the wavelength is selected so as to be an appropriate light source for any of the two types (first type and second type) having two different light characteristics. You can also. According to this, since the light source is not changed even if the type is changed, the convenience is high.

The wavelength to be selected is not particularly limited as long as the above relationship is satisfied, and may be selected from a region that can be detected by the detector 130 described later. Among these, it is preferable to be between the ultraviolet region on the short wavelength side and the infrared region on the long wavelength side. Furthermore, it is preferable to select the wavelength within the visible light range.
The type of the light source is not limited, but is preferably a light emitting diode (LED) from the viewpoint of power consumption and the life of the light source.

  The mixing ratio determining step S13 of each wavelength is a step of determining at what mixing ratio each wavelength should be irradiated when the wavelength selected in the light source selection (wavelength selection) step S12 is irradiated. is there. This is because the sample of the smallest defect that is difficult to detect (defect limit sample) is prepared, and the intensity of each wavelength (ie, the defect of the limit sample of the defect can be detected) This can be done by adjusting the mixing ratio of each wavelength. It is preferable to prepare all the defects to be detected (foreign matter, unevenness,...) As the types of defects in the defect limit sample.

  The light irradiating step S21 to the laminate is a step of irradiating the laminate 100, which is the subject, with light using the light sources 110 and 120 according to the conditions set in the condition setting step S10. That is, it is a step of irradiating light to a system having at least the light transmission layer 102 and the light reflection surface 101a on the optical path. When the laminated body 100 is irradiated with light, as shown in FIG. 4, the laminated body inspection apparatus and the laminated body 100 are arranged. The laminated body inspection apparatus includes a first light source 110, a second light source 120, a detector 130, and an image processing apparatus 140. In such a laminate inspection apparatus, the first light source 110 and the second light source 120 are arranged at a position where the laminate 100 can be irradiated with light obliquely. In FIG. 4, the first light source 110 and the second light source 120 are schematically illustrated as being arranged one by one, but actually, the plurality of first light sources 110 and the plurality of second light sources 120 are arranged on a plane. It is preferable that they are arranged in a line. More preferably, the first light source 110 and the second light source 120 can independently change the output intensity of each light source. This makes it possible to easily set the result of the above-described mixing ratio determination step S13 for each wavelength.

  In addition to the arrangement of the light sources 110 and 120 arranged in a plane as described above, a light source box is prepared, and the light from the two types of light sources output inside is provided with a light guide (optical fiber). May be used for irradiation.

  Further, the type of light source is not limited as long as it can output light having a necessary wavelength. In addition to the LED, a method in which a necessary wavelength is extracted from a fluorescent lamp, a halogen lamp, or a metal halide lamp using an optical filter is guided by a light guide or the like. Further, a sodium lamp or a laser may be used.

  In addition, the detector 130 is disposed in an optical path in which light emitted from the first light source 110 and the second light source 120 is reflected by the stacked body 100 and travels. The detector 130 is a device that receives the reflected light from the laminate 100 and converts it into an electrical signal. Therefore, the detector 130 has a lens system for collecting the received light and a photoelectric conversion element for converting the light received through the lens system into an electric signal. An example of this is a CCD camera. In addition to the CCD, the detector such as a photomultiplier tube or a CMOS sensor is not particularly limited as long as it is as described above, but is preferably a monochrome sensor. By being a monochrome sensor, an inspection image can be obtained as a monochrome luminance distribution.

  An image processing device 140 is connected to the detector 130. The image processing apparatus 140 is an apparatus that receives the electrical signal generated by the detector 130 and determines the presence or absence of a defect by performing image processing with the CPU based on a stored predetermined program. A known image processing apparatus can be applied to such an apparatus.

  With the apparatus configuration and the arrangement of the stacked body 100 as described above, light is irradiated from the first light source 110 and the second light source 120 toward the stacked body 100 in the light irradiation step S21 to the stacked body.

  The reflected light receiving step S <b> 22 is a step in which the above-described detector 130 receives reflected light with respect to the light emitted from the first light source 110 and the second light source 120 to the stacked body 100. Here, the received light is as follows. FIG. 4 shows an explanatory diagram. FIG. 7A illustrates an example of an optical path in which light (L110, L120) from the first light source 110 and the second light source 120 is reflected by the stacked body 100 (light reflection layer 101, light transmission layer 102). FIG. 7B illustrates an example of an optical path when only the first light source 110 is irradiated.

In the laminate 100 to which the light transmission layer 102 is applied, light is reflected as shown in FIG. The light L110 from the first light source 110 reaches the surface of the light transmission layer 102, and a part of the light is reflected on the surface to become the light L110b. The reflectivity (ratio of the light L110b to the light L110) at this time is determined by the incident angle and the refractive index of the layer regardless of the type, and is constant when these are the same (the same applies hereinafter).
The other part of the light L110 is incident on the inside of the light transmission layer 102. Here, as can be seen from FIG. 6A, the light transmission layer 102 easily transmits the light from the first light source 110, so that the incident light reaches the light reflection layer 101 while maintaining the intensity generally, Is reflected to become light L110a.
On the other hand, the light L120 from the second light source 120 reaches the surface of the light transmission layer 102, and a part thereof is reflected by the surface to become the light L120b. Further, another part of the light L120 enters the light transmission layer 102. Here, as can be seen from FIG. 6A, the light transmission layer 102 is difficult to transmit the light from the second light source 120, so that the incident light is weakened by absorption or the like and reaches the light reflection layer 101. Here, the light is reflected to become light L120a.

Thereby, the light reflection layer reflected light that is reflected by the light reflection layer 101 and reaches the detector 130 includes the light L110a and the light L120a. On the other hand, the light transmissive layer reflected light that is reflected by the light transmissive layer 102 and reaches the detector 130 includes light L110b and light L120b.
If only the light L110 from the first light source 110 is irradiated as shown in FIG. 7B, the intensity of the light reflection layer reflected light is relatively stronger than the light transmission layer reflection light. If the reflected light of the light reflecting layer is relatively large, there is an advantage that the detection sensitivity to the entry of foreign matters is improved. However, if the reflected light of the light reflecting layer is too large relative to the reflected light of the light transmitting layer, the light reflecting layer causes Noise increases, resulting in a reduction in sensitivity to film thickness unevenness.
On the other hand, according to the present invention, as shown in FIG. 7A, when the light is appropriately adjusted from the second light source 120 and irradiated with light, the light from the second light source 120 is transmitted through the light transmission layer 102. Therefore, it is possible to effectively increase the intensity of the reflected light of the light transmitting layer, and to make the intensity of the reflected light of the light transmitting layer relatively close to the intensity of the reflected light of the light reflecting layer. Therefore, while maintaining the intensity of the light reflected from the light reflecting layer, it is possible to balance with the light reflected from the light transmitting layer, the detection accuracy of various defects is high, and the noise caused by the light reflecting layer is reduced. Is possible.

  Thus, according to the present invention, it is possible to arbitrarily adjust the ratio of the light reflection layer reflection light and the light transmission layer reflection light, thereby balancing foreign matter detection, unevenness detection, and noise reduction. Is possible.

  FIG. 8 shows a diagram for explaining an example of an optical path in the case of the laminated body 100 ′ (light reflection layer 101, light transmission layer 102 ′). FIG. 8A illustrates an example of an optical path in which light (L110, L120) from the first light source 110 and the second light source 120 is reflected by the stacked body 100 ′, and FIG. It is a figure explaining the example of an optical path at the time of irradiating only 110. FIG.

In the laminate 100 ′ to which the light transmission layer 102 ′ is applied, light is reflected as shown in FIG. The light L110 from the first light source 110 reaches the surface of the light transmission layer 102 ′, and a part thereof is reflected by the surface to become light L110′b. Further, another part of the light L110 is incident on the inside of the light transmission layer 102 ′. Here, as can be seen from FIG. 6B, the light transmission layer 102 ′ is difficult to transmit the light from the first light source 110, so that the intensity of the incident light is weakened by absorption or the like and is reflected on the light reflection layer 101. It is reflected here and becomes light L110′a.
On the other hand, the light L120 from the second light source 120 reaches the surface of the light transmission layer 102 ′, and a part thereof is reflected by the surface to become light L120′b. The other part of the light L120 enters the light transmitting layer 102 ′. Here, as can be seen from FIG. 6B, the light transmissive layer 102 ′ easily transmits the light from the second light source 120, so that the incident light reaches the light reflecting layer 101 while the intensity is generally maintained. Here, the light is reflected to become light L120′a.

Thereby, the light reflected by the light reflecting layer 101 and reaching the detector 130 is reflected by the light L110′a and the light L120′a. On the other hand, the light transmissive layer reflected light that is reflected by the light transmissive layer 102 ′ and reaches the detector 130 includes light L110′b and light L120′b.
As shown in FIG. 8B, when only the light L110 from the first light source 110 is irradiated, the light transmission layer 102 ′ is difficult to transmit the light from the first light source 110. The intensity of the light reflected by becomes weaker. If the light reflection layer reflected light is relatively small with respect to the light transmission layer reflection light, noise due to the light reflection layer is reduced, and the sensitivity to film thickness unevenness is increased. If the light transmission layer is too small relative to the reflected light, the detection sensitivity with respect to the contamination of foreign matter is lowered.
On the other hand, according to the present invention, as shown in FIG. 8A, when light is irradiated with light intensity adjusted appropriately from the second light source 120, the light from the second light source 120 is transmitted through the light transmission layer 102. Can easily increase the intensity of the light reflected from the light reflecting layer, and the intensity of the light reflected from the light reflecting layer can be relatively close to the intensity of the light reflected from the light transmitting layer. It is possible to increase the reflected light of the light reflecting layer while removing the light. Therefore, the intensity of the light reflection layer reflected light can be increased while balancing the light reflection layer reflection light and the light transmission layer reflection light, the detection accuracy of various defects is high, and noise caused by the light reflection layer is reduced. It becomes possible to reduce.

  Thus, according to the present invention, it is possible to arbitrarily adjust the ratio of the light reflection layer reflection light and the light transmission layer reflection light, thereby balancing foreign matter detection, unevenness detection, and noise reduction. Is possible.

  As described above, according to the present invention, by using a plurality of light sources having different wavelengths, it is possible to obtain the light reflection layer reflection light and the light transmission layer reflection light in a balanced manner while maintaining the intensity of the reflection light. A plurality of types of defects can be detected in a balanced manner. Further, the configuration of the apparatus that enables such detection is not required to be complicated and is simple. Therefore, the reliability of the apparatus can be improved.

  In addition, even if the film thickness and characteristics (variety) of the light transmission layer change, the apparatus configured as described above is common as long as a plurality of light sources having appropriate wavelengths described so far are applied. Therefore, stable defect detection becomes possible.

  The reflected light as described above is received by the detector 130 and the information is converted into an electrical signal.

The image analysis step S23 is a step of calculating the electrical signal from the detector 130 by the above-described image processing device 140 and determining the presence or absence of a defect. Specifically, luminance (for example, 256 gradations) is obtained for each pixel of the detector 130, and an upper threshold value and a lower threshold value are provided for most of the normal luminance values. A part lower than the side threshold is recognized as a defect.
In the image analysis step, correction processing such as shading correction, moving average, and luminance correction may be performed to improve output stability. Further, in order to improve the detection sensitivity, a filtering process such as a directional filter, a primary differential filter, and a secondary differential filter can be performed.

  By incorporating the laminate inspection method described above into the laminate manufacturing process, it is possible to provide a laminate manufacturing method with high inspection accuracy and high yield. Here, among specific manufacturing methods of the laminate, a conventionally known method can be used for the process of forming the light reflecting layer and the light transmitting layer. For example, in the case of an electrophotographic photoreceptor, a cylindrical aluminum substrate, which is a member that becomes a light reflecting layer, is immersed in a storage liquid of a composition filled with a material that becomes a photosensitive layer that functions as a light transmission layer, It is possible to form a laminated body by drying.

  A high-quality laminate can be produced by applying the laminate inspection method described above in the middle of the production line to the laminate thus produced.

DESCRIPTION OF SYMBOLS 100 Laminated body 100 'Laminated body 101 Light reflection layer 101a Light reflection surface 102 Light transmission layer 102' Light transmission layer 110 First light source 120 Second light source 130 Detector 140 Image processing apparatus

Claims (10)

A method for inspecting a laminate, wherein a system having at least a light transmission layer and a light reflection surface on a light path is irradiated with light, and the reflected light is received to detect a defect.
Based on the light transmittance characteristics of the light transmissive layer, using a plurality of types of light sources having peak values at wavelengths with different transmittances, irradiating the laminate with light; and
Receiving a reflected light from the laminated body of the irradiated light with a detector;
Performing image processing based on the received information and detecting defects,
Inspection method for laminates.   The method according to claim 1, further comprising a step of selecting a plurality of types of light sources having peak values at wavelengths having different transmittances based on the light transmittance characteristics of the light transmissive layer before the step of irradiating the laminated body with light. Inspection method of the laminated body of description.   The laminate according to claim 2, further comprising a step of determining a mixing ratio of irradiation of the plurality of types of selected light sources after the step of selecting the light source and before the step of irradiating the laminate with light. Inspection method.   The laminated body inspection method according to claim 1, wherein the detector is a monochrome sensor.   The method for inspecting a laminate according to any one of claims 1 to 4, wherein peak values of wavelengths of the plurality of types of light sources are selected from wavelength regions that can be detected by the detector.   The laminated body inspection method according to claim 1, wherein the light source is an LED.   The said light source is a test | inspection method of the laminated body in any one of Claims 1-6 which can change output intensity for every kind of said multiple types.   The method for inspecting a laminate according to claim 1, wherein the laminate is an electrophotographic photoreceptor. The member to be the light reflecting surface has a step of laminating the light transmission layer, and the laminate is produced.
The manufacturing method of a laminated body including the process of detecting a defect with the inspection method of the laminated body in any one of Claims 1-8 for the produced said laminated body. A laminate inspection apparatus,
Based on the light transmittance characteristics of the light transmissive layer of the laminate, a plurality of types of light sources having peak values at wavelengths with different transmittances;
A detector that receives reflected light from the laminate of light emitted from the light source;
An image processing device that performs image processing based on the received information and detects defects;
Laminate inspection equipment.

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