JP2017110949A - Film checkup method, and film checkup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film checkup method by which films, even including films more subject to occurrence of waviness than near-infrared filters having glass substrates, can be easily and reliably checked up.SOLUTION: A film checkup method comprises a step of imaging light transmitted by a film from the surface and a step of determining any defect in the film by using imaging data acquired by this imaging step. At the imaging step, multiple sets of imaging data differing in focus are acquired, and at the determining step, any defect is determined by using the multiple sets of imaging data differing in focus. The film to be checked up is, for instance, a vapor deposition film. It is recommendable to use the optical intensity of the multiple sets of imaging data as defect determining information at the determining step. It is recommendable to use the ratio of dark areas not higher than a prescribed level of optical intensity in each set of imaging data as defect determining information at the determining step.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a film inspection method and a film inspection apparatus.

  A plasma display panel (PDP) operates using a plasma discharge, and it is known that near infrared rays (wavelength: 800 to 1000 nm) are generated during the plasma discharge. Such near infrared rays may cause malfunction of other devices. For this reason, the near-infrared cut filter is arranged on the front surface of the PDP. Such a near-infrared cut filter is also used in a CCD or CMOS image sensor such as a video camera.

  Various types of near-infrared cut filters are known. For example, a filter obtained by laminating a vapor deposition film on the surface of a glass substrate is known. Such a near-infrared cut filter is one that polishes the surface of a glass substrate, then deposits a metal on the surface of the substrate to form a deposited film, and reflects the near-infrared by the deposited film. . Such a near-infrared cut filter has a disadvantage that it is difficult to make it thinner, the manufacturing cost is high, and a glass piece of the base material is mixed as a foreign substance during cutting.

  For this reason, it has been proposed to use a film (deposited film) obtained by vapor-depositing a metal on a resin base material as a near-infrared cut filter (see, for example, Patent Document 1).

  However, this vapor-deposited film has the inconvenience that product inspection is difficult as compared with a near-infrared filter made of a glass substrate. As a cause of this, unlike the glass substrate, the near-infrared cut filter is swelled in the vapor deposited film at the time of inspection, and inspection noise is generated due to the swell. Further, as a cause of this, unlike the glass base material, the vapor deposition film does not polish the surface of the base material. Therefore, it is considered that inspection noise is caused by the surface properties of the base material.

JP 2010-044278 A

  The present invention has been made in view of such circumstances, and a film that can be easily and reliably inspected even if it is a film in which undulation or the like is likely to occur compared to a near-infrared filter made of a glass substrate. It is an object to provide an inspection method and a film inspection apparatus.

The invention made to solve the above problems is
A method for inspecting a film having a step of imaging the transmitted light of the film from the surface, and a step of determining a defect of the film using imaging data obtained in the imaging step,
In the imaging step, a plurality of imaging data with different focal points are acquired,
In the determination step, the defect is identified using a plurality of imaging data with different focal points.

  According to the film inspection method, by using a plurality of imaging data with different focal points obtained in the imaging step, it is possible to easily and reliably recognize a film defect in the determination step, and to easily and reliably inspect the film. It can be carried out.

  The film to be inspected is, for example, a vapor deposition film. Vapor deposition film is more likely to swell compared to conventional near-infrared filters made of glass substrates, and therefore, by inspecting the vapor deposition film by the film inspection method, reliable inspection can be easily performed. it can.

  As the defect recognition information in the determination step, the light intensity of the plurality of imaging data may be used. Thus, by using the light intensity of the imaging data, the film can be inspected more easily and reliably by the digitized data (light intensity).

  As the defect recognition information in the determination step, it is preferable to use a ratio of a dark region having a predetermined light intensity or less in each imaging data. In a film where a defect has occurred, the transmitted light is often weakened. Therefore, as described above, the ratio of the dark region can be used as defect qualification information, so that the film can be inspected more easily and reliably. it can. The dark region means a region where the light intensity of the region is not more than a threshold value (predetermined light intensity). The region is a partial region of the imaging data. For example, one pixel can be a single region, and a plurality of pixels can be a single region.

  When the imaging data is different from the non-defective product data and there is imaging data in which the dark area ratio is 0 among the plurality of imaging data, it may be recognized as an internal defect. The imaging data may differ from the non-defective product data due to the problem of the refractive index of the resin base material. Thus, when only the refractive index of a base material differs from a good product (when there is an internal defect), it may not be necessary to certify it as a defective product depending on the intended use of the film. As a result of intensive studies by the inventors, it has been found that when a plurality of pieces of imaging data are taken while changing the focus, there is imaging data having a dark area ratio of 0 in the case of only internal defects. On the other hand, in the case of a defect in which the deposited film has a defect (concave defect) or a defect in which foreign matter has adhered to the deposited film (convex defect), the dark area ratio among a plurality of imaging data with different focal points It will not be 0. For this reason, it is possible to easily and reliably identify the internal defect by determining whether or not there is imaging data in which the dark area ratio is 0 among a plurality of imaging data.

  The threshold value of the light intensity recognized as the dark region is preferably 10% or more and 40% or less of the maximum light intensity. Since the threshold value of the light intensity that is recognized as a dark region is within the above range, the determination step can be performed easily and reliably based on the appropriate dark region. In addition, it is preferable to set the said maximum intensity | strength so that the light intensity at the time of imaging the transmitted light of a non-defective film may be 50% of the maximum light intensity.

  As the defect recognition information in the determination step, it is preferable to use a ratio of a bright area that is equal to or higher than a predetermined light intensity in each imaging data. Thus, by using the ratio of the bright area as the defect certification information, the film can be inspected more easily and reliably. The bright region means a region where the light intensity of the region is equal to or greater than a threshold value (predetermined light intensity).

  As the defect recognition information in the determination step, it is preferable to use 0 or positive / negative of df (z) / dz, where z is the focal position of each image data, f (z) is the bright area ratio. Thus, by using 0 or positive / negative of df (z) / dz, the film can be inspected more easily and reliably.

  The threshold value of the light intensity recognized as the bright region is preferably 55% or more and 90% or less of the maximum light intensity. When the threshold value of the light intensity that is recognized as a bright region is within the above range, the determination step can be performed easily and reliably based on an appropriate bright region.

The film inspection method uses the ratio of dark areas below a predetermined light intensity and the ratio of light areas above a predetermined light intensity in each imaging data as defect qualification information in the determination step, and the focus of each imaging data. If the position is z, the bright area ratio is f (z), and the dark area ratio is g (z), there is z satisfying f (z ₀ ) = 0, and df (z) / dz when z <z ₀ Alternatively, if dg (z) / dz is negative, and if df (z) / dz or dg (z) / dz is positive when z> z ₀ , it may be recognized as an internal defect. As a result of intensive studies by the inventors, it has been found that f (z) and g (z) satisfy the above-described conditions when only a plurality of imaging data are taken with different focal points. For this reason, an internal defect can be recognized easily and reliably by determining whether f (z) and g (z) satisfy | fill the said conditions.

  The film inspection method uses the ratio of dark areas below a predetermined light intensity and the ratio of light areas above a predetermined light intensity in each imaging data as defect qualification information in the determination step. Among them, there is a case where there is no imaging data in which the dark area ratio is 0, the focal position of each imaging data is z, the bright area ratio is f (z), and df (z) / dz is positive. It is good to certify that it is a concave defect. As a result of intensive studies by the inventors, when a plurality of pieces of imaging data are taken with different focal points, f (z) and g (z) are the above in the case of a concave defect (in the case where a vapor deposition film is missing). It was found that the conditions were met. For this reason, it is possible to easily and reliably recognize the concave defect by determining whether f (z) and g (z) satisfy the above conditions.

  The film inspection method uses the ratio of dark areas below a predetermined light intensity and the ratio of light areas above a predetermined light intensity in each imaging data as defect qualification information in the determination step. Of these, if there is no imaging data with the dark area ratio of 0, and the focal position of each imaging data is z, the bright area ratio is f (z), and df (z) / dz is 0, the convex shape It is good to certify that it is a defect. As a result of intensive studies by the inventors, when a plurality of imaging data is obtained with different focal points, in the case of a convex defect (when a foreign substance is attached to the deposited film), f (z) and g ( It has been found that z) satisfies the above conditions. For this reason, it is possible to easily and reliably recognize the convex defect by determining whether f (z) and g (z) satisfy the above conditions.

  The film inspection method obtains primary data obtained by calculating the light intensity of each region based on the original data imaged in the imaging step, and corrects the primary data using the light intensity of the adjacent region to obtain the secondary data. It is preferable to obtain data and use this secondary data as defect recognition information in the determination step. Thereby, the defect can be easily and reliably identified using the corrected secondary data.

  The film inspection method further includes a step of supporting the film to be inspected on the imaging table, and a step of detecting the undulation of the film supported on the imaging table. In the imaging step, the swell detection The plurality of imaging data may be obtained by adjusting the focal position based on the swell detected by the process. As a result, a plurality of pieces of imaging data having different focal points can be obtained in response to the swell as the inspection target, thereby improving inspection accuracy.

Yet another invention made to solve the above problems is as follows:
An inspection device for a film comprising an imaging unit that images the transmitted light of the film from the surface, and a determination unit that certifies film defects using imaging data captured by the imaging unit,
The imaging unit acquires a plurality of imaging data with different focal points,
The determination unit performs defect recognition using a plurality of pieces of imaging data having different focal points.

  According to the film inspection apparatus, by using a plurality of imaging data with different focal points imaged by the imaging unit, the determination unit can easily and reliably recognize a film defect and easily and reliably inspect the film. It can be carried out.

  In addition, that a focus differs in several imaging data means that a focus position differs in the film thickness direction in the imaging data which images the same location of a film. The focal position is the position of the focal point in the film thickness direction when imaging. This focal position can be expressed as a numerical value by the distance from the center position (virtual center position) of the film when the film to be inspected is accurately positioned, for example.

  As described above, the present invention can easily and reliably inspect a film by using a plurality of imaging data with different focal points.

It is a schematic principal part expanded sectional view of the film which is the test object of the test | inspection method which is one Embodiment of this invention. It is a figure for demonstrating the defect of the film which is the test object of the test | inspection method which is one Embodiment of this invention, Comprising: (A) is an internal defect, (B) is a concave defect, (C) is a convex defect, respectively. It is a schematic principal part expanded sectional view for demonstrating. It is a schematic perspective view of the film inspection apparatus of one embodiment of the present invention. It is a figure for demonstrating the state at the time of the test | inspection of the film of FIG. 1, (A) is a schematic principal part expanded sectional view for demonstrating the film supported by the imaging table, (B) is imaging. It is a schematic principal part expanded sectional view for demonstrating the focus changed with a part. FIG. 3 is a graph obtained based on a plurality of imaging data of the film of FIG. 2, in which the horizontal axis is a focal position and the vertical axis is the number of pixels in a bright region or a dark region, and (A) is an internal defect As a result of the film, (B) shows the result of the film having a concave defect, and (C) shows the result of the film having a convex defect.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings as appropriate. First, an outline of a metal vapor deposition film which is a film to be inspected according to the present embodiment will be described.

[Deposited film]
The vapor deposition film 1 to be inspected in this embodiment has a resin base film 2 and a vapor deposition film 3 laminated on the base film 2 by metal vapor deposition, as shown in FIG. Yes. In addition, although it is also possible to laminate | stack the vapor deposition film 3 over the whole surface of the base film 2, in this embodiment, without performing vapor deposition to the peripheral part of the base film 2 surface, the base film 2 It is preferable to perform vapor deposition only on the central portion of the surface, thereby improving the undulation suppressing effect of the vapor deposition film 1 described later. In the present embodiment, the base film 2 has a square shape in plan view, and may be vapor-deposited on the entire surface of the base film 2, or may be partially vapor-deposited on the entire surface (deposition). It is also possible to arrange a region to be deposited and a region not to be deposited).

  The base film 2 is a multilayer structure including a plurality of resin layers 4 and 5 to be laminated. The vapor deposition film 1 in this embodiment is used as a near-infrared cut filter, and the base film 2 includes a first resin layer 4 containing a pigment and a second resin layer laminated on the first resin layer 4. And 5. Although it does not specifically limit as a main component of this 1st resin layer 4, Cyclic olefin resin is used suitably. Moreover, as a main component of the 2nd resin layer 5, although it does not specifically limit, an acrylic resin is used suitably.

  Next, the defect which may arise in the said vapor deposition film 1 is demonstrated, referring FIG. Defects that can occur in the deposited film 1 include internal defects, concave defects, convex defects, and the like.

  The internal defect is a case where an abnormality occurs in the refractive index of the base film 2. Specifically, as shown in FIG. 2 (A), there is a concave portion 1a (or convex portion) on the surface of the first resin layer 4, and a convex portion (or on the back surface of the second resin layer 5 corresponding to this. In some cases, the refractive index of the base film 2 may be abnormal due to the presence of the recesses. When such transmitted light of the vapor deposition film 1 is imaged, the imaging data differs from the non-defective product data due to the presence of internal defects. However, when used for applications such as an infrared cut filter, this internal defect does not cause a problem in terms of product. For this reason, when the defect is an internal defect, it is not always necessary to determine that the deposited film 1 is a defective product.

  The concave defect is a defect in which the concave portion 1b is present on the surface of the vapor deposition film 3 as shown in FIG. 2B, and specifically occurs when the vapor deposition film 3 is missing. The convex defect is a defect in which the convex portion 1c exists on the surface of the vapor deposition film 3 or the back surface of the base film 2 as shown in FIG. 2 (C), specifically, on the surface of the vapor deposition film 3 or the back surface of the base film 2. Occurs when foreign matter is attached.

[Inspection equipment]
As shown in FIG. 3, the vapor deposition film inspection apparatus according to one embodiment of the present invention uses an imaging unit 10 that images the transmitted light of the vapor deposition film 1 from the surface, and imaging data captured by the imaging unit 10. The determination part 20 which authenticates the defect of the metal vapor deposition film 1 is provided. The imaging unit 10 acquires a plurality of imaging data with different focal points. The determination unit 20 identifies a defect using the plurality of pieces of imaging data having different focal points.

(Imaging part)
The imaging unit 10 can change the focal point, and can acquire a plurality of imaging data with different focal points. The imaging unit 10 can be configured from various known imaging devices, for example, a CCD line sensor.

(Judgment part)
The determination unit 20 can be configured by a computer including an arithmetic processing unit such as an MPU, a ROM, a RAM, a hard disk, a monitor, an operation unit, and the like, and is based on a computer program stored in the ROM and the hard disk. The arithmetic processing unit controls each unit to perform desired authorization described later.

(Lighting part)
Moreover, the said vapor deposition film test | inspection apparatus has the illumination part (illustration omitted) facing the imaging part 10 on both sides of the vapor deposition film 1 supported by the imaging table. That is, the specific configuration of the illumination unit is not limited, but preferably includes a light source and an optical lens that emits light from the light source toward the imaging unit 10, and the Fresnel lens is used as the optical system lens. It is good to have.

(Imaging table and swell detector)
The vapor deposition film inspection apparatus includes an imaging table (not shown) that can support the vapor deposition film 1 so that the imaging unit 10 can capture an image, and a wave detection unit that detects the wave of the vapor deposition film 1 supported by the imaging table ( (Not shown).

  A conventionally known imaging table can be used as the imaging table. In the present embodiment, the imaging table has a mechanism for holding the vapor deposition film 1 in order to suppress the undulation of the vapor deposition film 1. This holding mechanism can sandwich the opposing sides or four corners of the vapor deposition film 1 and apply tension in directions away from each other, thereby improving the effect of suppressing the swell.

  As the swell detector, a conventionally known one can be adopted as long as it can detect the height of each part of the surface of the vapor deposition film 1 supported by the imaging table (relative height with other parts). For example, a laser displacement system can be used.

[Inspection method]
Next, the inspection method of the vapor deposition film of this embodiment is demonstrated.

  The said vapor deposition film test | inspection method has the process of determining the defect of the vapor deposition film 1 using the process which images the transmitted light of the vapor deposition film 1 from the surface, and the imaging data obtained by this imaging process.

(pre-process)
Moreover, the said vapor deposition film test | inspection method has the pre-process for reducing the waviness of the vapor deposition film 1 imaged before the said imaging process.

  This pre-process includes a step of supporting the vapor deposition film 1 on the imaging table and a step of detecting the undulation of the vapor deposition film 1 supported on the imaging table.

  The step of supporting the vapor deposition film 1 on the imaging table is a step of holding the vapor deposition film 1 on the holding mechanism of the imaging table. In this step, the entire pair of opposing sides (two sides) of the vapor deposition film 1 is held by the holding mechanism, and tension is applied in the direction in which the two sides are separated from each other (the orthogonal direction of the two sides).

  The waviness detection step is a step of detecting the height of each portion of the surface of the vapor deposition film 1 held by the holding mechanism of the imaging table as described above (relative height with other portions). And the said determination part 20 calculates the quantity (W1 in FIG. 4 (A)) of the waviness of the vapor deposition film 1. FIG. In addition, the amount of waviness can be the difference in height between the relatively lowest portion and the highest portion in the vapor deposition film 1. Note that FIG. 4A is only a schematic illustration for explanation, and exaggerates the swell.

(Imaging process)
In the imaging step, imaging is performed with different focal points, and a plurality of imaging data with different focal points are acquired. Specifically, as shown in FIG. 4B, the imaging unit 10 performs imaging while changing the focal point F within a predetermined range (W2).

  Here, the focal range W2 to be changed for imaging (the range in the thickness direction of the deposited film in which the focal point is changed when imaging the same portion (the distance between the focal point on the top surface side and the focal point on the back side of the film in the figure)) ) Is determined by the determination unit 20 based on the swell amount W1 detected in the swell detection step. This focal range W2 is preferably larger than the swell amount W1. The ratio of the focal range W2 to the waviness amount W1 is preferably 1.1 or more, more preferably 1.2 or more, and more preferably 1.3 or more. If the ratio is less than the lower limit, there is a possibility that a suitable inspection based on imaging data of a plurality of focal points cannot be performed on the entire surface of the deposited film 1. In addition, although the upper limit of the said ratio is not specifically limited, The said ratio is good in it being 3 or less (or 2 or less), for example. If the ratio exceeds the upper limit, the number of times of imaging may be excessively increased, or the focus pitch of each imaging data described later may be excessively widened.

  In the above description, the focus range W2 is determined based on the amount of swell W1, but the focus range W2 is set in advance, and imaging data with different focus in the set range W2 is obtained. It is also possible to obtain.

  Further, the focal range W2 is preferably 1 mm or more, more preferably 1.4 mm or more, and further preferably 1.8 mm or more. If the focal range W2 is less than the lower limit, there is a possibility that a suitable inspection based on the imaging data of a plurality of focal points cannot be performed on the entire surface of the vapor deposition film 1. The focal range W2 is preferably 3 mm or less, more preferably 2.6 mm or less, and even more preferably 2.2 mm or less. If the focal range W2 exceeds the above upper limit, the number of times of imaging may be excessively increased, or the focal pitch of each imaging data described later may be excessively widened.

  In the imaging step, as described above, imaging is performed a plurality of times by changing the focal point for each predetermined pitch in the focal range W2. Note that the focus can be changed by changing the position of the imaging unit 10 in the film thickness direction, or by changing the optical system (focus) of the imaging unit 10.

  Here, the focus pitch of each imaging data (the distance in the thickness direction of the deposited film between one focus and a focus adjacent to this focus) is not particularly limited, but is, for example, 250 μm. The pitch is preferably 50 μm or more, more preferably 200 μm or more, and further preferably 230 μm or more. The pitch is preferably 500 μm or less, more preferably 300 μm or less, and even more preferably 270 μm or less. When the pitch is within the above range, a highly accurate inspection can be easily performed with a suitable number of imaging data within a suitable focus range W2. If the pitch is less than the lower limit, there is a risk that the number of times of imaging will increase too much. Conversely, if the pitch exceeds the upper limit, the accuracy of inspection may be reduced.

  The number of times of imaging in the focus range W2 (number of times of imaging with different focal points) is not particularly limited, but is nine times, for example. The number of times of imaging is preferably 5 times or more, more preferably 7 times or more, and further preferably 8 times or more. The number of times of imaging is preferably 20 times or less, more preferably 15 times or less, and even more preferably 10 times or less. When the number of times of imaging is within the above range, it is possible to easily perform highly accurate inspection with imaging data obtained at a suitable pitch within a suitable focus range W2. If the number of times of imaging is less than the lower limit, the accuracy of inspection may be reduced. On the other hand, if the number of times of imaging exceeds the upper limit, the number of times of imaging is excessively increased and the inspection processing speed may be reduced.

(Judgment process)
In the determination step, the determination unit 20 identifies the defect using a plurality of pieces of imaging data having different focal points. The light intensity of the plurality of imaging data is used as defect recognition information in this determination step.

  The determination step includes a step of calculating the ratio of the dark region and the bright region for each imaging data, and a step of identifying a defect based on the ratio of the dark region and the bright region of each imaging data. The dark region is a region having a light intensity equal to or lower than a first threshold value in each image data. The bright area is an area having a light intensity equal to or higher than a second threshold value in each image data.

  In the step of calculating the ratio of the dark region and the bright region, the light intensity for each pixel (position information) of each imaging data is compared with the first and second threshold values, and pixels that are equal to or less than the first threshold value are dark regions. The pixels that are equal to or greater than the second threshold are recognized as bright regions, and the number of pixels in each of the dark region and the bright region is defined as the ratio of the dark region and the bright region.

  Specifically, for example, when there are 10 pixels below the first threshold and 20 pixels above the second threshold in one imaging data, the ratio of the dark area is 10 and the ratio of the bright area Is certified as 20 pieces. Note that pixels that are greater than or equal to the first threshold and less than or equal to the second threshold are not used as data. The ratio of the dark area and the bright area is recognized for each imaging data with different focus.

  The first threshold value and the second threshold value can be appropriately changed depending on the inspection target, the optical system to be used, etc., but the lower limit of the first threshold value is preferably 10% of the maximum light intensity, more preferably 20%. 30% is more preferable. On the other hand, the upper limit of the first threshold is preferably 40% of the maximum light intensity, more preferably 37%, and even more preferably 35%. When the first threshold value is within the above range, the determination step can be performed easily and reliably based on an appropriate dark region. If the first threshold value is less than the lower limit, it may not be possible to identify an originally defective one. When the first threshold value exceeds the upper limit, a portion that is not originally defective may be recognized as a defect. The maximum light intensity is set so that the light intensity when the transmitted light of the non-defective vapor deposition film 1 is imaged is 50% of the maximum light intensity.

  The lower limit of the second threshold is preferably 55% of the maximum light intensity, more preferably 58%, and even more preferably 60%. On the other hand, the upper limit of the second threshold is preferably 90% of the maximum light intensity, more preferably 70%, and even more preferably 65%. When the second threshold value is within the above range, the determination step can be performed easily and reliably based on an appropriate bright region. If the second threshold value is less than the lower limit, a portion that is not originally defective may be recognized as a defect. If the first threshold value exceeds the upper limit, it may not be possible to identify what is originally a defect.

  FIG. 5 shows the result of certifying the ratio of the dark area and the bright area for each imaging data with different focal points as described above. 5A shows the result of the vapor deposition film 1 having internal defects, FIG. 5B shows the result of the vapor deposition film 1 having concave defects, and FIG. 5C shows the result of the vapor deposition film 1 having convex defects. is there. In FIG. 5, the horizontal axis represents the focal position of the imaging data, and the vertical axis represents the number of pixels in the bright region or dark region of the imaging data at the focal point. In FIG. 5, the focal position 0 means that the center position (virtual center position) of the vapor deposition film and the focal point coincide with each other when the vapor deposition film is accurately held by the holding mechanism of the imaging table. The numerical value on the horizontal axis in FIG. 5 means the distance from the virtual center position to the focal point. When the numerical value is positive, it means that the focal point is closer to the imaging unit than the virtual central position.

  In the determination step, when the image data is different from the non-defective product data and there is image data having a dark area ratio of 0 among the plurality of image data, the determination unit 20 determines that the internal defect is present.

Specifically, there exists z satisfying f (z ₀ ) = 0, and z <is assumed when the focal position of each imaging data is z, the bright area ratio is f (z), and the dark area ratio is g (z). when z ₀ df (z) / dz or dg (z) / dz is negative, yet z> If when df (z) / dz or dg (z) / dz of _{z 0} is positive (FIG. 5 (See (A)), and the determination unit 20 recognizes that it is an internal defect.

  Further, in the determination step, if there is no image data having a dark area ratio of 0 among a plurality of image data and df (z) / dz is positive (see FIG. 5B), determination is made. Part 20 is identified as a concave defect.

  Further, in the determination step, there is no imaging data in which the dark area ratio is 0 among a plurality of imaging data, the focal position of each imaging data is z, and the bright area ratio is f (z). When (z) / dz is 0, the determination unit 20 determines that the defect is a convex defect.

[advantage]
According to the vapor deposition film inspection apparatus and inspection method, by using a plurality of imaging data with different focal points as described above, defects of the vapor deposition film 1 can be easily and reliably recognized, and the vapor deposition film can be easily and reliably inspected. Can be done. In particular, the vapor deposition film can be more easily and reliably inspected with the digitized data (light intensity) as the defect recognition information.

  In particular, the vapor deposition film inspection apparatus and the inspection method are not polished on the surface of the base film 2 unlike a glass base material, and are prone to waviness, although the inspection data has a lot of noise, As described above, highly accurate inspection can be easily performed.

  In addition, since the vapor deposition film inspection apparatus and inspection method can discriminate between other defects and internal defects as described above, in the case of a product that is not defective only with internal defects, it has only internal defects. The product can be distinguished from other defective products.

  Moreover, since a convex defect and a concave defect can also be discriminate | determined as mentioned above, the subsequent process can be performed smoothly with respect to each product.

  Furthermore, since the said vapor deposition film test | inspection method reduces a wave | undulation by giving tension | tensile_strength to a vapor deposition film before an imaging process, it can test | inspect with higher precision.

  Moreover, it has the process of detecting the wave | undulation of the vapor deposition film 1 supported by the imaging table, and by determining the focus range (focal change range) based on the wave | undulation detected by this process, it is more accurate. High inspection can be performed easily and reliably.

[Other Embodiments]
The present invention is not limited to the above-described embodiment, and can be appropriately modified within the scope intended by the present invention.

  In other words, in the above embodiment, the data captured in the imaging process is used as it is, and the determination process is performed. However, it is also possible to correct the captured original data and perform various determinations based on the correction data. It is. Specifically, primary data obtained by calculating the light intensity of each region based on the original data imaged in the imaging process is obtained, and this primary data is corrected using the light intensity of the adjacent region to obtain secondary data. Thus, this secondary data can be used as defect certification information in the determination step. Thereby, the defect can be easily and reliably identified using the corrected secondary data.

  Specifically, after performing desired image processing on each imaging data sent from the imaging unit, numerical values are obtained for position information (for example, X coordinate and Y coordinate) and light intensity (for example, data of 256 gradations). The primary data can be obtained by converting the data. Then, secondary data can be obtained by integrating with the light intensity of the adjacent position information (adjacent region).

  Moreover, although the said embodiment demonstrated what recognized an internal defect, a concave defect, and a convex defect, this invention is not limited to this, Defect identification using several imaging data from which a focus differs The design can be changed as appropriate as long as the operation is performed. For example, only one of an internal defect, a concave defect, and a convex defect, or one that certifies other defects is within the scope of the present invention.

  Furthermore, in the said embodiment, what had the process of detecting the wave | undulation of the vapor deposition film supported by this imaging table and the process of supporting a vapor deposition film on the imaging table as a pre-process of the process of imaging was demonstrated. However, in the present invention, the pre-process is not an essential component. Further, even when the pre-process is performed as in the above-described embodiment, it is not limited to the one that performs only the support process and the swell detection process. Before the support process, one of the deposited films is to suppress swell. It is also possible to perform a step of excising the part. Specifically, for example, in a pair of opposite sides (two sides) of a square-shaped deposited film, the central portion of each side is cut out while leaving the four corner portions (two sides other than the two sides to be cut are the same as the four corner portions) By holding the two sides that are not cut by the holding mechanism, biaxial warpage can be suppressed uniaxially, and undulation can be easily suppressed as a whole.

  As mentioned above, since this invention can test | inspect a film easily and reliably, it can be used suitably for the test | inspection of the vapor deposition film used for a near-infrared cut filter, for example.

1 Film (deposition film)
1a, 1b, 1c Defect 2 Base film 3 Deposition film 4 First resin layer 5 Second resin layer 10 Imaging unit 20 Determination unit

Claims (15)

A method for inspecting a film having a step of imaging the transmitted light of the film from the surface, and a step of determining a defect of the film using imaging data obtained in the imaging step,
In the imaging step, a plurality of imaging data with different focal points are acquired,
In the determination step, the defect is identified using a plurality of imaging data with different focal points.   The inspection method according to claim 1, wherein the film is a vapor deposition film.   The method for inspecting a film according to claim 1 or 2, wherein the light intensity of the plurality of imaging data is used as defect recognition information in the determination step.   The film inspection method according to claim 3, wherein a ratio of a dark region having a predetermined light intensity or less in each imaging data is used as the defect recognition information in the determination step.   The film inspection method according to claim 4, wherein the imaging data is recognized as an internal defect when the imaging data is different from non-defective product data and there is imaging data in which the dark area ratio is 0 among the plurality of imaging data.   The method for inspecting a film according to claim 4 or 5, wherein a threshold value of light intensity recognized as the dark region is 10% or more and 40% or less of the maximum light intensity.   The film inspection method according to any one of claims 2 to 6, wherein a ratio of a bright region having a predetermined light intensity or more in each imaging data is used as defect recognition information in the determination step.   The film inspection method according to claim 7, wherein as the defect qualification information in the determination step, the focal position of each imaging data is z, the bright area ratio is f (z), and 0 or positive / negative of df (z) / dz is used. .   The method for inspecting a film according to claim 7 or 8, wherein a threshold value of the light intensity recognized as the bright region is 55% or more and 90% or less of the maximum light intensity. As the defect qualification information in the determination process, the ratio of the dark area below the predetermined light intensity and the ratio of the bright area above the predetermined light intensity in each imaging data are used.
When z is the focal position of each of the imaging data, f (z) is the bright area ratio, and g (z) is the dark area ratio, there is z satisfying f (z ₀ ) = 0, and z <z ₀ If df (z) / dz or dg (z) / dz is negative, and if df (z) / dz or dg (z) / dz is positive when z> z ₀ , it is recognized as an internal defect. The method for inspecting a film according to claim 3. As the defect qualification information in the determination process, the ratio of the dark area below the predetermined light intensity and the ratio of the bright area above the predetermined light intensity in each imaging data are used.
There is no imaging data in which the dark area ratio is 0 among the plurality of imaging data, and the focal position of each imaging data is z, the bright area ratio is f (z), and df (z) / dz is positive. The method for inspecting a film according to claim 3, wherein the defect is recognized as a concave defect. As the defect qualification information in the determination process, the ratio of the dark area below the predetermined light intensity and the ratio of the bright area above the predetermined light intensity in each imaging data are used.
There is no imaging data in which the dark area ratio is 0 among the plurality of imaging data, and the focal position of each imaging data is z, the bright area ratio is f (z), and df (z) / dz is 0. If it becomes, it will be recognized as a convex defect, The inspection method of the film of Claim 3.   Primary data obtained by calculating the light intensity of each region based on the original data imaged in the imaging step is obtained, and this primary data is corrected using the light intensity of the adjacent region to obtain secondary data. The film inspection method according to claim 3, wherein the next data is used as defect certification information in the determination step. A step of supporting the film to be inspected on the imaging table, and a step of detecting the undulation of the film supported on the imaging table;
The film inspection method according to any one of claims 1 to 13, wherein in the imaging step, the plurality of imaging data is obtained by adjusting a focal point based on the undulation detected by the undulation detection step. An inspection apparatus for a film comprising an imaging unit that images the transmitted light of the film from the surface, and a determination unit that detects film defects using imaging data captured by the imaging unit,
The imaging unit acquires a plurality of imaging data with different focal points,
The film inspecting apparatus, wherein the determination unit performs defect recognition using the plurality of imaging data having different focal points.

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