JP2010169649A - Method and device for inspecting defect of conductive film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and device for inspecting a defect of a conductive film, capable of accurately inspecting the conductive film formed of a conductive layer in non-contact. <P>SOLUTION: This device for inspecting the defect includes a microwave radiating means for radiating microwave to the conductive film having the conductive layer, a surface temperature distribution measuring means for measuring the temperature distribution of the surface of the conductive film irradiated with the microwave, and a quality determining means for detecting a defect of the conductive layer of the conductive film based on a measurement result on the surface temperature distribution measuring means. The microwave is radiated to the conductive film having the conductive layer, the conductive layer is heated, and temperature distribution on the surface of the conductive film are measured, thereby detecting the defect on the conductive layer of the conductive film. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a defect inspection method and a defect inspection apparatus for a conductive film on which a conductive layer is formed. In particular, it is a defect inspection method and defect inspection apparatus for a conductive film suitable for defect inspection of a transparent conductive film in which a transparent conductive layer is formed on a polymer film. In addition, although the material of a polymer film is not specifically limited, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), etc. correspond.

  A conductive film with a conductive layer formed on a polymer film is widely used as an electrode for transparent touch panels, and in recent years, it has been increasingly used for film displays such as electronic paper, and its production volume is rapidly increasing. .

  The polymer film is required to have excellent transparency in the visible region and elastic strength, heat resistance and low hygroscopicity. Currently, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), etc. It is used. The thickness of the film is selected in the range of 20 μm to 250 μm depending on the application in consideration of the balance between flexibility and strength.

  In addition, as a conductive layer, from the viewpoint of achieving both transparency and conductivity, oxidation of indium tin oxide (ITO), indium zinc oxide (IZO), fluorine doped tin oxide (FTO), zinc oxide (ZnO), etc. Things are mainly used. The film thickness varies depending on the required conductivity, but is an extremely thin film in the range of several tens to several hundreds of nanometers, and is mainly formed by a vacuum process such as sputtering or vapor deposition.

  This conductive film is processed into a desired shape by coating or bonding in a so-called roll-to-roll process. Further, the conductive layer may be subjected to pattern etching as necessary.

  In such a roll-to-roll process, processing utilizing the plasticity of the polymer film is possible, while the oxide forming the conductive layer is poor in flexibility and is resistant to elongation and bending of the polymer film serving as the substrate. Insufficient followability. As a result, the conductive layer may be cracked or scratched. Since the cracks and scratches progress in the film thickness direction of the conductive layer, the conductivity in the surface direction of the conductive film is deteriorated. As a result, the function of the conductive layer as an electrode is lowered, and the performance of a product using this conductive film is hindered. For example, when a crack occurs in a conductive layer of a conductive film used for a simple matrix type display, a display defect due to a poor energization is caused.

  In order to prevent such product defects, it is desirable to detect defects such as cracks and scratches in the conductive layer during the processing of the conductive film.

  Conventionally, visual inspection is performed as a method for detecting such a defect. In visual inspection, transmitted light or reflected light is used to detect defects by observing from various angles, but even if a range of about several tens of centimeters is observed, it takes about 1 minute, Inspection of the full length of the continuum in the roll-to-roll process takes a long time, and there is a concern of inspection errors due to fatigue. Therefore, an apparatus for inspecting a defect of a conductive layer is desired. Since the polymer film is easily scratched by mechanical pressure, it is necessary to detect it without contact when detecting cracks or scratches in the conductive layer.

  As an apparatus for detecting a defect in a non-contact manner, there is an inspection apparatus for a transparent electrode film substrate as described in Patent Document 1. The inspection apparatus described in Patent Document 1 can detect defects such as pinholes generated in a thin film forming process of a transparent electrode layer formed on a glass substrate.

  Further, Patent Document 2 discloses an inspection method capable of determining whether a wiring pattern such as a transparent electrode is difficult to see. The inspection apparatus described in Patent Document 2 energizes a wiring pattern, generates infrared rays from the wiring patterns, images the infrared rays, and determines pass / fail.

JP 2004-20254 A JP 11-337454 A

  However, the defect inspection apparatus described in Patent Document 1 is based on the premise of detecting defects in the transparent conductive layer formed on the glass substrate, and cracks associated with deformation of the substrate such as the conductive layer of the conductive film. The drawbacks of are difficult to detect.

  In addition, in the defect inspection apparatus described in Patent Document 2, mechanical contact for voltage application cannot be completely avoided, so that it is unsuitable for a polymer film such as a conductive film as a substrate. It is.

  Therefore, an object of the present invention is to provide a defect inspection method and a defect inspection apparatus for a conductive film, which can accurately perform a non-contact inspection of a conductive film formed with a conductive layer.

In order to solve the above problems, the invention described in claim 1
Irradiating a conductive film having a conductive layer with microwaves,
Heating the conductive layer,
By measuring the temperature distribution on the surface of the conductive film,
A defect inspection method for a conductive film, characterized by detecting a defect in a conductive layer of a conductive film.

  According to invention of Claim 1, when a microwave is irradiated to the conductive layer of a conductive film, a conductive layer will be heated by an eddy current loss. At this time, since the state of heat generation varies depending on the surface resistance of the conductive layer, the heat generation is changed in the defective part of the crack or scratch that affects the resistance value of the conductive layer. By measuring such a change in heat generation in a non-contact manner, the defect of the conductive layer can be detected without damaging the conductive film.

The invention described in claim 2
In the invention of claim 1,
Irradiate a good conductive film with microwaves,
By measuring the temperature distribution on the surface of the conductive film, the reference temperature distribution is obtained,
A defect inspection method for a conductive film, wherein the defect of the conductive layer of the conductive film is detected by comparing the reference temperature distribution and the temperature distribution measured for each conductive film.

  According to the second aspect of the present invention, since the reference temperature distribution is a non-defective product, the temperature distribution between the inspection object and the non-defective product can be relatively compared, and the reliability of the inspection can be obtained.

  For example, even if the microwave could not uniformly irradiate the surface of the conductive film with the intensity distribution, it was obtained from the non-defective product by repeating the microwave irradiation similar to that for measuring the temperature distribution of the non-defective product. The conductive film to be inspected can be inspected by relative comparison with the reference temperature distribution. Therefore, it is possible to detect the defect of the conductive layer satisfactorily without depending on the variation in the microwave irradiation.

The invention according to claim 3
In the invention of claim 1,
After the conductive layer of the conductive film running continuously at a constant speed is irradiated with microwaves to heat the conductive layer, the conductive film surface temperature distribution is measured on the downstream side of the conductive film running direction,
A method for inspecting a defect in a conductive film, comprising: obtaining trend data indicating a change over time in a measured value of a surface temperature distribution, and detecting the defect by comparing the surface temperature distribution data of the conductive film for each measurement with the trend data. It is.

  According to the third aspect of the present invention, the conductive film temperature and apparatus temperature before microwave irradiation gradually change due to the influence of the external environment and the like, the surface resistance of the conductive film is the same, and the temperature distribution after irradiation is Even in the case of gradual changes, by comparing the conductive film surface temperature distribution data of each measurement with the trend data, it is possible to avoid recognizing the above temperature distribution change over time as a defect, and to improve the defect of the conductive layer. Can be detected.

The invention according to claim 4
Microwave irradiation means for irradiating a conductive film having a conductive layer with microwaves;
Surface temperature distribution measuring means for measuring the temperature distribution of the surface of the conductive film irradiated with microwaves;
An apparatus for inspecting a defect of a conductive film, comprising: a quality determination unit that detects a defect of the conductive layer of the conductive film based on a measurement result of the surface temperature distribution measuring unit.

According to invention of Claim 4,
By detecting the eddy current loss generated in the conductive layer of the conductive film by microwave irradiation using the surface temperature distribution measuring means, it is possible to detect defects due to cracks and scratches generated in the conductive layer. Can be measured in a non-contact manner.

The invention described in claim 5
In the invention of claim 4,
The pass / fail judgment means obtains a reference temperature distribution by measuring the temperature distribution of the surface of a good conductive film with the surface temperature distribution measuring means,
An apparatus for inspecting a defect of a conductive film, characterized in that it is a quality determination output means for detecting a defect of a conductive film by comparing the reference temperature distribution with a temperature distribution measured for each conductive film.

According to the invention of claim 5,
Since the pass / fail judgment means sets the temperature distribution of the non-defective conductive film to the reference temperature distribution, the temperature distribution between the inspection object and the non-defective product can be relatively compared, and the reliability of the inspection can be obtained.

The invention described in claim 6
In the invention of claim 4,
Film transport means for continuously running the conductive film at a constant speed;
The pass / fail judgment means obtains trend data indicating the change over time of the measured value of the surface temperature distribution of the conductive film, and detects pass / fail by detecting the fault by comparing the conductive film surface temperature distribution data for each measurement with the trend data. An apparatus for inspecting a defect of a conductive film, which is a means.

According to the invention of claim 6,
The defect detection means can detect the temperature distribution of the running conductive film and judge whether it is good or bad.

  ADVANTAGE OF THE INVENTION According to this invention, the defect inspection method and defect inspection apparatus of a conductive film which can perform the defect detection which becomes the electroconductive defect which arises in the conductive film which forms a conductive layer accurately without contact can be provided.

It is the structure schematic of the defect inspection apparatus of the electrically conductive film which concerns on this invention. It is sectional drawing of a conductive film basic composition. It is sectional drawing of the electrically conductive film structure which added the additional function. It is a figure explaining the fault which affects the electroconductivity of a conductive film. It is the figure which simulated the structure of the light-receiving surface of an infrared sensor. It is a block diagram explaining the fault inspection method of a conductive film. It is the surface temperature distribution data of the conductive film measured in Example 1. It is the surface temperature distribution data of the conductive film measured in Example 2. It is the surface temperature distribution data of the conductive film measured in Example 2. It is a figure which shows the surface temperature distribution measurement range in Example 2. FIG.

  Next, the present invention will be described in more detail with reference to the drawings. FIG. 1 is a schematic diagram of a defect inspection apparatus for a conductive film of the present invention, and shows a state in which a conductive film 10 is inspected as an inspection object. FIG. 2 shows a cross section of the conductive film 10.

  First, the conductive film 10 shown in FIG. 2 will be described. The conductive film 10 includes a polymer film substrate 11 having a predetermined thickness. The polymer film substrate 11 is excellent in transparency in the visible region, and is required to have elastic strength, heat resistance and low hygroscopicity. Polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), etc. It is used. Further, the thickness of the polymer film substrate 11 is selected in the range of 20 μm to 250 μm depending on the application in consideration of the balance between flexibility and strength. A conductive layer 12 is formed on the polymer film substrate 11, and the material of the conductive layer 12 is indium tin oxide (ITO), indium oxide zinc (IZO) from the viewpoint of achieving both transparency and conductivity. ), Oxides such as fluorine-doped tin oxide (FTO) and zinc oxide (ZnO) are mainly used. The thickness of the conductive layer 12 varies depending on the required conductivity, but is an extremely thin film in the range of several tens to several hundreds of nanometers, and is mainly formed by a vacuum process such as sputtering or vapor deposition.

  The conductive film 10 of the present invention is preferably a transparent conductive film having a light transmittance of 50% or more for visible light having a wavelength of 550 nm.

  Moreover, as a structure of the conductive film 10, in addition to the polymer film 11 substrate and the conductive layer 12, a base treatment layer 13, a surface treatment layer 14, and a back treatment layer 15 shown in FIG. Although the role of each layer varies depending on the use of the conductive film 10, the base treatment layer 13 improves the bonding strength between the polymer film substrate 11 and the conductive layer 12, the surface treatment layer 14 protects the conductive layer 12, and the back treatment layer 15 has a high strength. For example, the mechanical strength of the molecular film surface is improved.

The conductivity of the conductive layer 12 varies depending on the application, and the surface resistance is several tens Ω / □ or less for display applications, several hundred Ω / □ or less for touch panel applications, and higher than 10 ⁶ Ω / □ for antistatic applications. . The influence of the conductive layer 12 due to the microwave irradiation varies depending on the surface resistance of the conductive layer 12, and a spark is generated when the resistance is less than 1 Ω / □, and when the surface resistance exceeds 10 ⁴ Ω / □, the conductive layer 12 is affected by the microwave irradiation. The heating efficiency is lowered, and it takes time to increase the temperature, and the influence of heat diffusion into the surface of the conductive film 10 cannot be ignored. Therefore, the conductive film 10 of the present invention desirably has a surface resistance of the conductive layer 12 in the range of 1 to 10 ⁴ Ω / □.

  Note that the defect 16 of the conductive layer 12 to be inspected in the present invention includes a scratch 161, a crack 162, a pinhole 163, and a partially thin wall 164 shown in FIG. Both of these adversely affect the conductivity of the conductive layer 12 and lead to a failure of a product (touch panel or film display) using the conductive film 10.

  As shown in FIG. 1, the conductive film 10 is normally handled as a continuous body, and is continuously connected between the film unwinding portion 21 and the film winding portion 22 in the present embodiment as well. The conductive film 10 is conveyed from the film unwinding unit 21 to the film winding unit 22 by controlling the film conveying mechanism 20 including the film unwinding unit 21 and the film winding unit 22 by the control unit 50. In FIG. 1, only the film unwinding unit 21 and the film winding unit 22, which are the minimum configuration, are shown as the film transporting mechanism 20. A speed control mechanism may be included as needed.

  The microwave irradiation device 30 is configured to guide the microwave generated by the microwave oscillator 31 such as a magnetron to the microwave irradiation region 300 through the waveguide 32, and the output and irradiation time of the microwave are controlled by the control unit 50. Be controlled. As a microwave frequency, in principle, heating is possible in a wide frequency range, but it is necessary to select from a so-called ISM frequency in order to avoid adverse effects on communication equipment, and either 2.45 GHz or 5.8 GHz is required. It is reasonable.

  The microwave irradiation device 30 corresponds to the microwave irradiation means of the present invention.

  As the surface temperature distribution measuring device 40, an infrared thermography is suitable, and an infrared sensor 41 used in the infrared thermograph has a large number of light receiving elements 411 on its light receiving surface as schematically shown in FIG. They are arranged in a matrix. As shown in FIG. 6, the surface temperature distribution data imaged by the infrared sensor 41 is input to the quality determination means 42 and is compared with reference temperature distribution data described later by the quality determination means 42. . Here, reference temperature distribution data used as a criterion for pass / fail judgment is stored in the storage unit 43. Further, the determination result is displayed on the display unit 44, but preferably has a function of being stored in the storage unit 43 together with the position information of the conductive film 10.

  Further, after the surface temperature distribution data is stored in the storage unit 43, the storage is accumulated as the surface temperature distribution trend data indicating the temporal change of the surface temperature distribution. The pass / fail judgment means 42 has a function of making a pass / fail judgment by relatively comparing the surface temperature distribution measurement data and the surface temperature distribution trend data at each position of the conductive film 10.

  In addition, as the region of the conductive film 10 for measuring the surface temperature distribution in the surface temperature distribution measuring device 40, the region under microwave irradiation is preferable for measurement, but the electromagnetic noise to the electronic circuit of the infrared sensor 41 due to the microwave is preferably measured. In order to avoid influence, in this Embodiment, it is set as the system which measures the surface temperature distribution of the conductive film 10 after the microwave irradiation ends.

  The surface temperature distribution measuring device 40 corresponds to the surface temperature distribution measuring means of the present invention.

  A defect inspection method 1 using the conductive film defect inspection apparatus of the present invention will be described below.

<Defect inspection method 1>
First, the non-defective conductive film 10 is transported to the microwave irradiation region 300 of the microwave irradiation device 30 by the film transport mechanism 20. The non-defective conductive film 10 is determined by observing the stationary conductive film 10 by visual inspection in advance. In this case, the presence or absence of a defect is determined by irradiating the conductive layer 12 of the conductive film 10 with visible light and observing the conductive layer 12 from various angles.

Next, the microwave output from the microwave oscillator 31 is irradiated to the conductive film 10. Thereby, an eddy current is generated in the conductive layer 12 of the conductive film 10 and the surface temperature of the conductive film 10 is increased. Here, the positional relationship between the microwave irradiation direction and the conductive layer 12 can be inspected even if the nonconductive surface of the conductive film 10 is on the microwave irradiation side, but the conductive layer 12 is on the microwave irradiation side. It is preferable that it exists in. Note that the power and irradiation time of the microwaves irradiated here need to be such that the temperature of the conductive film 10 does not exceed the glass transition point of the polymer film substrate 11 serving as the substrate by heating due to the irradiation. On the other hand, the effect when irradiated with microwaves depends on the surface resistance of the conductive layer 12, and sparking occurs when the resistance is less than 1 Ω / □, and heating efficiency decreases when the resistance exceeds 10 ⁴ Ω / □, and the temperature rise takes time. In short, the influence of heat diffusion into the surface of the conductive film 10 cannot be ignored.

  Thereafter, the conductive film 10 that has been subjected to microwave irradiation is advanced to the measurement region 400 of the surface temperature distribution measuring device 40 by the film transport mechanism 20, and the surface temperature of the conductive film 10 after microwave irradiation is measured by the surface temperature distribution measuring device 40. Measure the distribution. The surface temperature distribution data is stored in the storage unit 43 as reference temperature distribution data. This is the process of obtaining the reference temperature distribution data.

  Note that the time from the completion of microwave irradiation to the conductive film 10 in the microwave irradiation region 300 to the start of surface temperature distribution measurement in the measurement region 400 is within 5 seconds. When this time exceeds 5 seconds, the original surface temperature distribution becomes different due to heat conduction in the plane of the conductive film 10 and heat radiation from the surface of the conductive film 10. In the above description, the conductive film 10 is intermittently operated so as to stop the conductive film 10 in the microwave irradiation region 300 and the measurement region 400. However, the conductive film 10 receives microwave irradiation in the microwave irradiation region 300, and the measurement region. If the surface temperature distribution can be measured at 400, the conductive film 10 can be continuously run.

  After obtaining this reference temperature distribution data, the defect inspection of the conductive film 10 can be performed. In the defect inspection step, first, the conductive film 10 whose presence or absence of the defect 16 is unknown is conveyed to the microwave irradiation region 300 of the microwave irradiation device 30. Here, it is a premise that the conductive film 10 has the same specifications as the above-described non-defective conductive film 10. That is, the material and thickness of the polymer film 11 of the conductive film 10 and the material, thickness, and surface resistance of the conductive layer 12 are the same standard (when the base treatment layer 13, the surface treatment layer 14, and the back treatment layer 15 are present, respectively. Must be of the same standard).

  Next, the microwave output from the microwave oscillator 31 is irradiated under the same conditions (output, time, distribution and positional relationship between the microwave irradiation direction and the conductive layer 12) as the non-defective conductive film 10 is irradiated. Thereafter, the conductive film 10 that has been subjected to microwave irradiation is advanced to the measurement region 400 of the surface temperature distribution measuring device 40 by the film transport mechanism 20, and the surface temperature of the conductive film 10 after microwave irradiation is measured by the surface temperature distribution measuring device 40. Measure distribution data. At this time, the time until the measurement of the surface temperature distribution of the conductive film 10 after microwave irradiation is the same as when the non-defective conductive film 10 was measured.

  The surface temperature distribution data obtained here is determined by the pass / fail judgment means 42 if the previously obtained reference temperature distribution data matches or is within a certain difference (set from the measurement error level). It is determined as “good”. On the other hand, in the region having the defect 16 in the conductive layer 12, the temperature around the defect portion is different from the reference temperature distribution data in the non-defective product due to the defective conductivity of the defect portion. In this way, it is possible to detect a defect of the conductive layer 12 of the conductive film 10 that is transparent to visible light, which is difficult to detect with ordinary optical equipment. If the comparison with the reference temperature distribution data is not performed, the surface temperature distribution of the conductive film 10 due to the variation in the irradiation intensity of the microwave is recognized as a defect of the conductive layer 12.

  In the present embodiment, the pass / fail judgment means 42 performs pass / fail judgment by relatively comparing the surface temperature distribution data, but the average value of the surface temperature of the non-defective conductive film 10 is obtained, and You may perform relative comparison of. Further, the pass / fail judgment may be made by measuring a temporal change of the surface temperature and relatively comparing the temperature profile (change of the surface temperature of the conductive film 10 after the microwave irradiation). Further, the defect detection of the conductive film 10 may be performed by integrating or differentiating the temperature profile on the time axis.

  Next, a defect inspection method 2 using the conductive film defect inspection apparatus of the present invention will be described.

<Defect inspection method 2>
First, the film transport mechanism 20 starts transporting the conductive film 10 and gradually increases the transport speed and operates the microwave irradiation device 30. Then, the inspection is started when the transport speed of the conductive film 10 and the output of the microwave oscillator 31 of the microwave irradiation device 30 are stabilized at a predetermined value. At this time, the position in the length direction of the conductive film 10 entering the upstream side of the microwave irradiation region 300 is defined as L1.

After the operation of the microwave irradiation device 30, the conductive film 10 is irradiated with the microwave output from the microwave oscillator 31. Thereby, an eddy current is generated in the conductive layer 12 of the conductive film 10 and the surface temperature of the conductive film 10 is increased. Here, the positional relationship between the microwave irradiation direction and the conductive layer 12 can be inspected even if the nonconductive surface of the conductive film 10 is on the microwave irradiation side, but the conductive layer 12 is on the microwave irradiation side. It is preferable that it exists in. Note that the power of the microwaves irradiated here needs to be such that the temperature of the conductive film 10 does not exceed the glass transition point of the polymer film substrate 11 serving as the substrate by heating due to the irradiation. On the other hand, the effect when irradiated with microwaves depends on the surface resistance of the conductive layer 12, and sparking occurs when the resistance is less than 1 Ω / □, and heating efficiency decreases when the resistance exceeds 10 ⁴ Ω / □, and the temperature rise takes time. In short, the influence of heat diffusion into the surface of the conductive film 10 cannot be ignored.

  After that, the film transport mechanism 20 advances the microwave-irradiated conductive film 10 to the surface temperature distribution measuring device 40 side, and the length direction position L1 of the conductive film 10 is the maximum in the measurement region 400 of the surface temperature distribution measuring device 40. When reaching the downstream part, the surface temperature distribution measuring device 40 measures the surface temperature distribution of the conductive film 10 after microwave irradiation. The surface temperature distribution measurement data DL1 is stored in the storage unit 43.

  Note that the time from when the length direction position L1 of the conductive film passes through the most downstream portion of the microwave irradiation region 300 to the most downstream portion of the measurement region 400 to perform the surface temperature distribution measurement is 5 seconds. Within. When this time exceeds 5 seconds, the original surface temperature distribution becomes different due to heat conduction in the plane of the conductive film 10 and heat radiation from the surface of the conductive film 10.

  Thereafter, the surface temperature distribution measuring device 40 measures the surface temperature distribution at a stage where L2 reaches the position of the most downstream portion of the measurement region 400 of the surface temperature distribution measuring device 40 through a predetermined time interval T. The surface temperature distribution measurement data DL2 is stored in the storage unit 43.

  Furthermore, the surface temperature distribution measuring device 40 measures the surface temperature distribution when the position L3 of the most downstream portion of the measurement region 400 of the surface temperature measuring device 40 has reached a predetermined time interval T. The surface temperature distribution measurement data DL3 is stored in the storage unit 43.

  Similarly, the surface temperature distribution is measured at a stage where L4, L5, L6,..., Ln reach the most downstream portion of the surface temperature distribution measuring device 40 at predetermined time intervals T, and the surface temperature distribution is measured. The measurement data DL4, DL5, DL6,..., DLn are stored in the storage unit 43.

  In addition, since the conveyance speed V of the conductive film 10 is constant and the time interval T is also constant, the intervals ΔL between the length direction positions L1, L2,..., Ln−1, Ln of the conductive film 10 are ΔL. = V × T and constant. Therefore, if ΔL is equal to or shorter than the length Y0 of the measurement region 400 of the surface temperature measuring device 40 in the conductive film running direction, measurement without omission over the length direction of the conductive film 10 is possible.

  The pass / fail judgment means 42 includes surface temperature distribution measurement data DL1, DL2,..., DLn-1 at the length direction positions L1, L2,..., Ln-1, Ln of the conductive film 10 stored in the storage unit 43. , DLn is accumulated, an approximate expression of the surface temperature distribution trend with respect to the position in the length direction of the conductive film 10 is obtained, and the length direction position L1, L2,. 1, surface temperature distribution trend data DTL1, DTL2,..., DTLn-1, DTLn are obtained, and these surface temperature distribution trend data are stored in the storage unit 43.

  Then, the pass / fail judgment means 42 compares the surface temperature distribution measurement data DL1 and the surface temperature distribution trend data DTL1 at the position L1 in the length direction of the conductive film 10, and they match or are constant (set from the measurement error level). If it is within the difference, the area is determined to be “good”. On the other hand, when the difference exceeds a certain value, it is determined that the probability that the defect 16 exists in the conductive layer 12 in the region is high. Thereafter, it is possible to determine whether or not there is a defect in each region by performing the same comparison at the length direction positions L2, L3,..., Ln-1 and Ln of the conductive film.

  Examples inspected using the defect inspection method 1 described in the embodiment will be described.

  The conductive film 10 having a thickness of 125 μm and a width of 200 mm wound in a roll shape was used (the conductive surface was the inside of the roll). The configuration of the conductive film 10 is a PET film as the polymer film substrate 11, the conductive layer 12 is ITO formed by sputtering, the surface resistance is 180Ω / □, and the light transmittance for visible light with a wavelength of 550 nm is 84%. there were.

  The conductive film 10 is set between the film unwinding unit 21 to the film winding unit 22 in FIG. 1, and the conductive film 10 is transported and stopped so that the portion determined to be non-defective by visual observation enters the microwave irradiation region 300. The region was irradiated with microwaves.

  At that time, the microwave frequency was 2.45 GHz, the oscillator output was 30 W, and the irradiation time was 30 seconds.

  Then, the part which received microwave irradiation by the film conveyance mechanism 20 was conveyed / stopped to the measurement area 400 of the surface temperature distribution, and the surface temperature distribution data was measured by infrared thermography.

  Here, the time from the end of microwave irradiation to the start of measurement of the surface temperature distribution data of the conductive film 10 was set to 2 seconds.

  The result of showing the surface temperature distribution data of the conductive film 10 in this measurement in the width direction of the conductive film 10 is as shown in FIG.

  Next, microwave irradiation to surface temperature distribution measurement was performed under the same conditions as the above-mentioned non-defective part for a part where an intentional ITO crack was generated near the center in the width direction of the conductive film 10. The result of showing the surface temperature distribution data of the conductive film 10 in this measurement in the width direction of the conductive film 10 is as shown in FIG. By comparing FIG. 7A and FIG. 7B, the influence of the conductive failure due to the ITO crack is reflected in the surface temperature distribution data by the microwave irradiation.

  Therefore, by comparing FIG. 7 (a) and FIG. 7 (b), it was possible to detect a defect generated in the conductive layer 12 of the conductive film 10.

  An example inspected using the defect inspection method 2 described in the embodiment will be described.

  The conductive film 10 having a thickness of 100 μm and a width of 160 mm wound in a roll shape was used (the conductive surface was the inside of the roll). The conductive film 10 is composed of a PET film as a polymer film serving as a substrate, the conductive layer 12 is ITO formed by sputtering, the surface resistance is 180Ω / □, and the light transmittance for visible light with a wavelength of 550 nm is 84%. Met.

  The conductive film 10 is set between the film unwinding unit 21 to the film winding unit 22 in FIG. 1, the conveyance speed V is set to 10 cm / sec by the film conveyance mechanism, and conveyance is started. Was activated and microwave irradiation was started. The frequency of the microwave at that time was 2.45 GHz, and the set output of the oscillator was 100 W. Further, since the length of the microwave irradiation region 300 in the traveling direction of the conductive film 10 is 20 cm, it takes 2 seconds for the conductive film 10 to be irradiated with the microwave irradiation.

  Thereafter, the surface temperature distribution data of the conductive film 100 conveyed by the film conveyance mechanism 20 is measured by infrared thermography in the surface temperature distribution measurement region 400 further downstream of the microwave irradiation region 300. The distance from the most downstream portion of the microwave irradiation region 300 to the most upstream portion of the surface temperature distribution measurement region 400 was set to 15 cm. Further, the length Y0 in the running direction of the conductive film in the surface temperature measurement region is 15 cm. Therefore, the distance from the most downstream portion of the microwave irradiation region 300 to the most downstream portion of the surface temperature measurement region 400 is 30 cm, and the traveling speed V of the conductive film 10 is 10 cm / sec. The time from leaving 300 to measuring the temperature distribution is 3 seconds.

  In this apparatus, the time when the power of the microwave oscillator 31 and the traveling speed of the conductive film 10 are stabilized at the set values is the start of the measurement. At this time, the length of the conductive film in the most upstream part of the microwave irradiation region 300 is increased. When the vertical direction position L1 reaches the most downstream portion of the surface temperature measurement area 400, the surface temperature distribution is measured to obtain surface temperature distribution measurement data DL1. Thereafter, surface temperature measurement data is obtained with a measurement period T of 1 second. Here, since this measurement cycle T is 1 second, the running speed V of the conductive film is 10 cm / sec, and the surface temperature measurement range Y0 in the running direction of the conductive film is 15 cm, T ≦ Y0 / V is established. is doing.

  Surface temperature distribution trend data was obtained from an approximate expression using the surface temperature distribution measurement data obtained at 10 cm intervals. In this embodiment, the quadratic approximation is used as the approximation formula, but there is no significant difference even when another polynomial approximation formula such as the cubic approximation is used.

  Next, comparison between surface temperature distribution measurement data and surface temperature distribution trend data will be shown. 8A and 8B show the surface temperature distribution measurement data and the surface temperature distribution trend data at the 10.0 m point after the start of measurement. In the measurement, a two-dimensional temperature distribution is measured. In FIGS. 8A and 8B, a straight line in the width direction of the conductive film passing through the center point O in the surface temperature measurement region 400 shown in FIG. The surface temperature distribution at the top XO is shown. 9A and 9B show surface temperature distribution measurement data and surface temperature distribution trend data at a point of 112.0 m after the start of measurement. Both FIG. 9A and FIG. 9B show the surface temperature distribution in the width direction of the conductive film, as in FIG. 8A and FIG. 8B.

  When comparing FIG. 8 (a) and FIG. 8 (b), there is no significant difference between the surface temperature distribution measurement data and the surface temperature distribution trend data, and the conductive film 10 near 10.0 m is visually observed after the measurement is started. But I couldn't find any defects. On the other hand, in the comparison between FIG. 9A and FIG. 9B, the surface temperature distribution measurement data in FIG. 9A is greatly different from the surface temperature distribution trend data in FIG. 9B. Actually, when the conductive film 10 near 112.0 m was visually observed after the start of measurement, it was found that a crack was generated in a part of the conductive layer.

DESCRIPTION OF SYMBOLS 10 Conductive film 11 Polymer film board | substrate 12 Conductive layer 13 Ground treatment layer 14 Surface treatment layer 15 Back surface treatment layer 16 Defect of conductive layer 20 Film conveyance mechanism 21 Film unwinding part 22 Film winding-up part 30 Microwave irradiation apparatus 31 Microwave Oscillator 32 Waveguide
300 Microwave Irradiation Area 40 Surface Temperature Distribution Measurement Device 41 Infrared Sensor 42 Pass / Fail Judgment Unit 43 Storage Unit 44 Display Unit 400 Measurement Area

Claims (6)

Irradiating a conductive film having a conductive layer with microwaves,
Heating the conductive layer,
By measuring the temperature distribution on the surface of the conductive film,
A method for inspecting a defect of a conductive film, comprising detecting a defect of a conductive layer of a conductive film. In the invention of claim 1,
Irradiate a good conductive film with microwaves,
By measuring the temperature distribution on the surface of the conductive film, the reference temperature distribution is obtained,
A method for inspecting a defect of a conductive film, wherein the defect of the conductive layer of the conductive film is detected by comparing the reference temperature distribution with a temperature distribution measured for each conductive film. In the invention of claim 1,
After the conductive layer of the conductive film running continuously at a constant speed is irradiated with microwaves to heat the conductive layer, the conductive film surface temperature distribution is measured on the downstream side of the conductive film running direction,
A method for inspecting a defect in a conductive film, comprising: obtaining trend data indicating a change over time in a measured value of a surface temperature distribution, and detecting the defect by comparing the surface temperature distribution data of the conductive film for each measurement with the trend data. . Microwave irradiation means for irradiating a conductive film having a conductive layer with microwaves;
Surface temperature distribution measuring means for measuring the temperature distribution of the surface of the conductive film irradiated with microwaves;
A defect inspection apparatus for a conductive film, comprising: a quality determination unit that detects a defect of the conductive layer of the conductive film based on a measurement result of the surface temperature distribution measuring unit. In the invention of claim 4,
The pass / fail judgment means obtains a reference temperature distribution by measuring the temperature distribution of the surface of a good conductive film with the surface temperature distribution measuring means,
An apparatus for inspecting a defect of a conductive film, comprising means for determining whether or not a defect of the conductive film is detected by comparing the reference temperature distribution with a temperature distribution measured for each conductive film. In the invention of claim 4,
Film transport means for continuously running the conductive film at a constant speed;
The pass / fail judgment means obtains trend data indicating the change over time of the measured value of the surface temperature distribution of the conductive film, and detects pass / fail by detecting the fault by comparing the conductive film surface temperature distribution data for each measurement with the trend data. A defect inspection apparatus for a conductive film, characterized in that the apparatus is a means.

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