JP2008292201A - Method and apparatus for inspecting laminated film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated film inspection method capable of accurately inspecting the whole region of a separator when inspecting a laminated film in which the separator having variations in phase differences is laminated. <P>SOLUTION: When detecting defects of the laminated film 1 in which a polarizer 14 and the separator 11 are laminated, the laminated film inspection method has the process for irradiating the laminated film 1 through the use of a light source 2 for inspection; the process for photographing transmitted light images by the light source 2 for inspection via a polarizing filter 4 for inspection and a phase difference filter 3 for inspection; the process for positioning the polarizing filter 4 for inspection and the phase difference filter 3 for inspection for every region of a plurality of small regions 1a into which an inspection region of the laminated film 1 is divided; the process for detecting a rotational position at which transmitted light is absorbed most by rotating the positioned phase difference filter 3; and the process for photographing transmitted light images of the small regions 1a at a detected rotational position. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention provides a process of irradiating a laminated film using an inspection light source when detecting defects in a laminated film in which at least a polarizer and a retardation layer are laminated, and a transmitted light image by the inspection light source The present invention relates to a method for inspecting a laminated film having a step of photographing through a polarizing filter for inspection and a phase difference filter for inspection, and a defect detection apparatus for a laminated film suitable for this method.

  As such a laminated film, there is one having a laminated structure as illustrated in FIG. The laminated film 1 includes a polarizing plate 16 composed of a protective layer 13 laminated on both sides of a polarizer 14 via an adhesive layer, and a separator laminated on one surface of the polarizing plate 16 via an adhesive layer 12. 11 (corresponding to a retardation layer). When inspecting defects such as foreign matter, scratches, and nicks present on the polarizing plate 16, the polarizing plate 16 is irradiated with light from an appropriate light source, and the reflected light image and the transmitted light image are displayed as a line sensor or a two-dimensional TV. The defect detection is performed based on the acquired image data acquired through a photographing unit such as a camera. When the polarizing plate 16 is inspected, image data is acquired in a state where an inspection polarizing filter is interposed in the optical path between the light source and the imaging means. Usually, the polarization axis (for example, the polarization absorption axis) of the polarizing filter for inspection is arranged to be in a state (crossed Nicols) orthogonal to the polarization axis (for example, the polarization absorption axis) of the polarizing plate 16 to be inspected. The By arranging in crossed Nicols, if there is no defect, a black image is input from the imaging means, but if there is a defect, that portion will not become black. Therefore, a defect can be detected by setting an appropriate threshold value.

  However, when the polarizing plate 16 is the laminated film 1 having the separator 11, the separator 11 has birefringence (phase difference). The polarizing plate 16 and the inspection polarizing filter are not in a crossed Nicols state. As a result, there has been a problem that the defect inspection of the polarizing plate 16 included in the laminated film 1 cannot be accurately performed. When the laminated film 1 is used for a liquid crystal display device or the like, the separator 11 is finally peeled off and used. However, in the inspection process of the laminated film 1, the separator 11 is present. Must be inspected.

  As an apparatus for detecting a defect of a laminated film that solves such a problem, a polarizing plate inspection apparatus disclosed in Patent Document 1 is known. This polarizing plate inspection apparatus has a light source and a polarizing filter for inspection that converts light from the light source into linearly polarized light. The linearly polarized light is input to a polarizing plate with a protective film (corresponding to a retardation layer) and transmitted therethrough. Defect detection is performed based on the optical image. Further, a phase difference plate (inspection phase difference filter) that compensates for the birefringence of light by the protective film is disposed on the optical path that passes through the polarizing plate with the protective film from the light source. By separately disposing this retardation plate, the phase change due to the protective film is canceled, and the birefringence of light due to the protective film is compensated. Furthermore, in order to compensate for birefringence caused by a slightly different protective film for each product, a configuration example is also disclosed in which a variable polarization optical element capable of adjusting the phase angle of light by voltage is arranged.

JP 2005-9919 A

  However, the above prior art also has the following problems. Although the phase difference of the separator can be canceled by using the inspection phase difference filter, the phase difference of the separator itself varies, and therefore varies depending on the region even in the same product. Therefore, even if it can be canceled in a certain area, it may not be canceled in a different area, and there is still room for improvement in terms of the certainty of the inspection result. Further, there is a problem that wavelength dispersion occurs due to the characteristics of the separator, and the transmitted light has a plurality of polarization states, so that the phase difference cannot be completely cancelled.

  The present invention has been made in view of the above circumstances, and the problem is that when inspecting a laminated film in which separators having retardation variations are inspected, it is possible to inspect the entire area of the separator with high accuracy. An object of the present invention is to provide a method for inspecting a possible laminated film and a defect detection apparatus for a laminated film suitable for this method.

In order to solve the above problems, the inspection method of the laminated film according to the present invention is as follows.
At least, when performing defect detection of a laminated film in which a polarizer and a retardation layer are laminated,
A method for inspecting a laminated film comprising: irradiating a laminated film using a light source for inspection; and photographing a transmitted light image from the light source for inspection through a polarizing filter for inspection and a phase difference filter for inspection. There,
The inspection area of the laminated film is set to be divided into a plurality of small areas, and the step of positioning the inspection polarizing filter and the inspection phase difference filter for each area;
Rotating the positioned inspection phase filter to detect the rotational position where the transmitted light is most absorbed,
And a step of photographing a transmitted light image of the small region at the detected rotational position.

  The operation and effect of the laminated film inspection method with this configuration will be described. As for the laminated | multilayer film used as a test object, the polarizer and the phase difference layer are laminated | stacked at least. An inspection light source is disposed on one side of the film surface of the laminated film, and an imaging means (for example, an area sensor camera or a line sensor camera) is disposed on the other side. In addition, an inspection polarizing filter and an inspection phase difference filter are disposed in the optical path between the inspection light source and the imaging means. If the laminated film is normal, the transmitted light that has passed through the polarizer of the laminated film passes only linearly polarized light, and the defect portion also transmits light other than linearly polarized light. Therefore, if the polarizing filter for inspection is arranged in crossed Nicols with respect to the polarizer of the laminated film, the transmitted light image in the originally non-defective area becomes black and the defective portion is displayed brightly. However, since the phase difference layer does not actually result in a crossed Nicols state, a transmitted light image is acquired in a state where the phase difference due to the phase difference layer is canceled by interposing an inspection phase difference filter. Is possible.

  In consideration of the fact that the phase difference of the retardation layer varies depending on the region, the inspection region of the laminated film is divided into a plurality of small regions. This is because it is considered that there is no large phase difference variation in the divided small regions. Then, the inspection polarizing filter and the inspection phase difference filter are positioned for each region. At this position, the phase difference filter for inspection is rotated to detect the rotational position where the transmitted light is most absorbed. By setting to this rotational position, it is possible to perform inspection in a state set to crossed Nicols. The rotation position of the inspection phase difference filter as described above is set in order for each small region. Therefore, by setting an appropriate inspection phase difference filter for each of the divided small areas, it is possible to perform an accurate defect inspection for all the inspection areas of the laminated film.

  In the present invention, it is preferable that a rotation angle range of the inspection phase difference filter is set in advance, and the rotation position is detected while being moved by a predetermined angle pitch within the angle range.

  Since the range of retardation variation of the retardation layer of the laminated film is considered to be limited to some extent, it is expected that the appropriate rotational position of the phase difference filter for inspection is also within a certain range. Is possible. Thus, the inspection efficiency can be improved by setting the rotation angle range of the phase difference filter for inspection not to 360 ° but to an angle range narrower than that. The phase difference filter for inspection can detect the position where the transmitted light is absorbed most efficiently by moving the phase difference filter by a predetermined angle pitch within this angular range.

  In the present invention, the irradiation light from the inspection light source preferably has a center wavelength of 600 to 700 nm and a half width of 50 nm or less.

  By setting to such a range, when a transmitted light image photographed by the photographing means is displayed on a monitor or the like, the contrast between the defective part and the other normal part is increased, and it is easy to make a visual judgment. Further, as the center wavelength of the irradiation light becomes longer or the wavelength band is narrowed, chromatic dispersion is less likely to occur, and the accuracy of inspection can be increased.

In order to solve the above problems, a laminated film inspection apparatus according to the present invention comprises:
At least, when performing defect detection of a laminated film in which a polarizer and a retardation layer are laminated,
A laminated film inspection apparatus comprising: an inspection light source that irradiates a laminated film; and an imaging unit that photographs a transmitted light image from the inspection light source through an inspection polarizing filter and an inspection phase difference filter,
The inspection area of the laminated film is divided and set into a plurality of small areas, and filter position setting means for positioning the inspection polarizing filter and the inspection phase difference filter for each area,
And a filter position detecting means for detecting the rotational position where the transmitted light is most absorbed by rotating the inspection phase difference filter positioned,
The transmitted light image of the small area is photographed by the photographing means at the detected rotational position.

  The operation and effect of the laminated film inspection apparatus having such a configuration is as described above, and by setting an appropriate inspection retardation filter for each divided small area of the laminated film, An accurate defect inspection can be performed on the inspection region.

In order to solve the above problems, another laminated film inspection method according to the present invention is as follows.
At least, when performing defect detection of a laminated film in which a polarizer and a retardation layer are laminated,
Irradiating the laminated film using the first inspection light source, and photographing the transmitted light image from the first inspection light source through the first inspection polarizing filter and the first inspection phase difference filter; And having
Furthermore, the step of irradiating the laminated film using the second inspection light source, and the step of receiving the transmitted light from the second inspection light source through the second inspection polarizing filter and the second inspection phase difference filter, A method for inspecting a laminated film comprising:
The inspection area of the laminated film is divided and set into a plurality of small areas, and the second inspection polarizing filter and the second inspection retardation filter are positioned for each area;
Rotating the positioned second inspection phase difference filter to detect a rotational position where transmitted light is most absorbed;
Storing the detected rotational position for each small region;
Positioning the first inspection polarizing filter and the first inspection phase difference filter for each region;
Setting the rotational position of the first inspection phase difference filter based on the stored rotational position;
And a step of taking a transmitted light image of the small area after setting the first inspection phase difference filter.

  The operation and effect of the inspection method of the laminated film having such a configuration will be described. According to the inspection method described above, the inspection area of the laminated film is divided into a plurality of small areas, and each of the small areas is moved in order to find the appropriate rotation position of the phase difference filter for inspection while transmitting the transmitted light image. It was to take a picture and inspect. On the other hand, in this inspection method, first, an appropriate rotation position of the inspection phase difference filter is detected for all the small regions, and then each small region is sequentially moved to detect the phase difference for inspection. The inspection is performed by photographing the transmitted light image while setting the filter at the rotation position that has been detected in advance. For this purpose, a second inspection light source, a second inspection polarizing filter, and a second inspection phase difference filter are prepared, and the rotation position of the appropriate inspection phase difference filter is found and stored using these. Let me. When the defect inspection is actually performed, the stored rotational position data is read, and the first inspection phase difference filter used for the defect inspection is set at the rotational position. The transmitted light image is taken at the set position. With this configuration, accurate defect inspection can be performed for all inspection regions of the laminated film.

  In the present invention, the irradiation light from the first inspection light source preferably has a center wavelength of 600 to 700 nm and a half width of 50 nm or less.

  By setting to such a range, when a transmitted light image photographed by the photographing means is displayed on a monitor or the like, the contrast between the defective part and the other normal part is increased, and it is easy to make a visual judgment. Further, as the center wavelength of the irradiation light becomes longer or the wavelength band is narrowed, chromatic dispersion is less likely to occur, and the accuracy of inspection can be increased.

  In the present invention, the rotation angle of the second inspection phase difference filter is at least 360 °, and it is preferable that the transmitted light is received by the photodiode.

  According to this configuration, it is possible to find an appropriate rotation position of the inspection phase difference filter while continuously rotating the second inspection phase difference filter at a high speed. In addition, by receiving the transmitted light with a photodiode, the processing time can be shortened, and a highly accurate defect inspection can be performed while suppressing the inspection time.

In order to solve the above-mentioned problem, another laminated film inspection apparatus according to the present invention comprises:
At least, when performing defect detection of a laminated film in which a polarizer and a retardation layer are laminated,
A first inspection light source that irradiates the laminated film, and an imaging unit that captures a transmitted light image from the first inspection light source through the first inspection polarization filter and the first inspection phase difference filter. ,
And a second inspection light source for irradiating the laminated film, and a light receiving means for receiving the transmitted light from the second inspection light source through the second inspection polarization filter and the second inspection phase difference filter. An inspection device for laminated film,
Sub-filter position setting means for setting the inspection area of the laminated film to be divided into a plurality of small areas, and positioning the second inspection polarizing filter and the second inspection phase difference filter for each area;
A filter position detecting means for rotating the positioned second inspection phase difference filter to detect a rotational position where the transmitted light is most absorbed;
Storage means for storing the detected rotational position for each small region;
Main filter position setting means for positioning the first inspection polarizing filter and the first inspection phase difference filter for each region;
Filter rotation position control means for setting the rotation position of the first inspection phase difference filter based on the stored rotation position,
After the first inspection phase difference filter is set, the transmitted light image of the small area is photographed by the photographing means.

  The inspection device for the laminated film with such a configuration is as described above, and for each of the divided areas of the laminated film, by setting an appropriate inspection phase difference filter, for all the inspection areas of the laminated film, Accurate defect inspection can be performed.

  DESCRIPTION OF EMBODIMENTS Preferred embodiments of a laminated film inspection apparatus and inspection method according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram illustrating a configuration of an inspection apparatus and an inspection method. Examples of the laminated film to be inspected include those having a laminated structure as shown in FIGS. In FIG. 2A, protective layers 13 are provided on both surfaces of a polarizer 14, and a separator 11 (corresponding to a retardation layer) is laminated on one protective layer 13 via an adhesive layer 12. . A protective film 11 ′ is laminated on the other protective layer 13 side. The laminated film 1 shown in FIG. 2B is a configuration example in which a retardation film 15 is further laminated between the protective layer 13 and the pressure-sensitive adhesive layer 12.

<Inspection Method and Apparatus According to First Embodiment>
In FIG. 1, the inspection area of the laminated film 1 is divided into a plurality of small areas 1a. Although it is divided into 32 small regions 1a in the figure, the number of divisions can be set as appropriate and is not limited to this. An inspection light source 2 is disposed below the laminated film 1, and an inspection retardation filter 3, an inspection polarizing filter 4, and a photographing camera 5 (corresponding to photographing means) are disposed above the laminated film 1. Has been. The photographing camera 5 is not limited to a specific type. In order to reduce the influence of the phase difference variation of the separator 11 as much as possible, a method of narrowing the field of view by using an area sensor camera is preferable. However, since the inspection time becomes longer if the field of view is set narrow, a line sensor camera is used. May be.

  The inspection polarizing filter 4 is arranged so that the angle of the absorption axis is perpendicular to the absorption axis of the polarizer 14 of the laminated film 1 (crossed Nicols). With such an arrangement, if there is no defect in the laminated film 1, the linearly polarized light obtained by the polarizer 14 cannot pass through the inspection polarizing filter 4, and thus becomes a black image. If there is a defect, the defect portion transmits light other than linearly polarized light, so that the defect portion (hereinafter referred to as “bright spot”) is displayed brightly. By detecting the presence of this bright spot, it is possible to determine whether or not there is a defect in the laminated film 1.

  Actually, since the crossed Nicols state does not occur due to the presence of the separator 11 (retardation layer), the phase difference due to the separator 11 is canceled by interposing the inspection retardation filter 3. The inspection retardation filter 3 is preferably selected in accordance with the laminated structure of the retardation film 15 so that the transmitted light becomes the weakest in combination with the inspection polarizing filter 4.

  The type of the inspection light source 2 is not particularly limited, but preferably has a wavelength band limited to avoid the influence of chromatic dispersion. Specifically, it is preferable that the wavelength of irradiation light is 600 to 700 nm and the full width at half maximum is 50 nm or less. In order to limit the wavelength band, there are a method of using an LED or a helium neon laser as a light source, a method of narrowing the band by combining an appropriate light source and a color filter, and the like.

  FIG. 3 is a conceptual diagram showing the configuration of the laminated film inspection apparatus according to the first embodiment. On the gantry 20, a first stage 21 and a second stage 22 (corresponding to filter position setting means) for mounting the laminated film 1 to be inspected are provided. The first stage 21 can be moved in the Y direction by a first slider 23 provided on the second stage 22, and the second stage 22 can be moved in the X direction by a second slider 24 provided on the gantry 20. Is possible. Therefore, the first stage 21 can move in the XY plane with respect to the gantry 20, and the laminated film 1 mounted on the first stage 21 can also move in the XY plane.

  The inspection light source 2 is provided below the first and second stages 21 and 22, and light passage holes are formed in the stages 21 and 22 so that the irradiation light can pass therethrough.

  An inspection phase difference filter 3 and an inspection polarizing filter 4 are arranged in this order above the first and second stages 21 and 22, and a photographing camera 5 is further provided above them.

  The inspection phase difference filter 3 is supported so as to be rotatable about an optical axis L (a line connecting the center of the inspection light source 2 and the photographing camera 5). A driving gear is provided on the outer peripheral portion of the holding body that holds the inspection phase difference filter 3, and an intermediate gear 26 that is rotationally driven by the motor 25 is disposed in mesh with the driving gear, whereby the inspection phase difference filter 3 is provided. Can be rotated.

  The computer 30 controls the operation of the motor 25 and the photographing camera 5 and takes in image data photographed by the photographing camera 5.

<Control function>
FIG. 4 is a block diagram showing the control function of the inspection apparatus shown in FIG. The computer 30 is provided with a controller 31 that comprehensively controls the entire apparatus. The camera control unit 32 controls the operation of the photographing camera 5 and can perform control of capturing a transmitted light image of the laminated film 1. The phase difference filter control unit 33 (corresponding to the filter position detecting means) has a function of giving a command to the motor 25 and controlling the rotation of the inspection phase difference filter 3. The stage control unit 34 performs drive control on the first and second stages 21 and 22.

  The control program 35 stores a program for controlling the inspection apparatus shown in FIG. Specifically, the rotation control of the inspection phase difference filter 3 and the driving of the first and second stages 21 and 22 are performed based on a program stored in advance. The image processing unit 36 appropriately processes the transmitted light image of the laminated film 1 captured by the photographing camera 5 and displays the processed light image on the monitor 37. The operator can determine the presence / absence or non-defectiveness of the laminated film 1 while looking at the image displayed on the monitor 37.

  The brightness determination unit 38 has a function of determining the most appropriate rotation position of the inspection phase difference filter 3 based on the light amount data of the transmitted light image acquired while rotating the inspection phase difference filter 3. Specifically, it has a function of finding the rotation position where the transmitted light is absorbed most, that is, the rotation position where the transmitted light amount is determined to be the smallest, while rotating the inspection phase difference filter 3.

  The storage means 39 stores a transmitted light image (image data) captured by the photographing camera 5. The storage means 39 can be constituted by a large-capacity hard disk or the like.

<Inspection procedure>
Next, the inspection procedure by the inspection apparatus according to the first embodiment will be described with reference to the flowcharts of FIGS. FIG. 5 is a diagram showing the divided small areas 1 a of the laminated film 1. In this example, the small area 1a is divided into a total of 32 small areas 1a of 4 × 8. Each small area 1a is provided with a reference numeral, and the inspection order is indicated by A → B → C →... EE → FF as indicated by arrows.

  As shown in the flowchart of FIG. 6, first, the laminated film 1 to be inspected is mounted on the first stage 21 (S1). Next, the stages 21 and 22 are driven so that the optical axis L is positioned at the center of the small area A of the laminated film 1 (S2). Next, the inspection polarizing filter 4 is arranged so as to be in a crossed Nicols state (S3). Next, the inspection phase difference filter 3 is set to a predetermined angular position (S4). The position of the inspection polarizing filter 4 is fixed until the inspection of one laminated film 1 is completed.

  Next, the inspection phase difference filter 3 is rotated by 1 °, and the transmitted light image of the small area A is acquired by the photographing camera 5 at this rotational position (S5, S6). This operation is repeated 40 times in total, and a transmitted light image in the range of 40 ° (corresponding to the set angle range) is acquired in 1 ° steps. Among the obtained transmitted light images, the transmitted light image having the weakest transmitted light is selected, and the transmitted light image at the rotational position is determined to be image data to be used for the determination of the defect inspection (S7, S8). It is determined whether or not there is a bright spot in the transmitted light image data (S9).

  This determination may be made by visual judgment by the operator, or may be determined using an image processing technique. As a determination method, a method of counting the number of bright spots or obtaining an area (individual area, total area, etc.) of bright spots can be considered. When all the collection of bright spot information in the small area A is acquired (S10), the first and second stages 21 and 22 are moved, and the same operation for the small area B is repeated (S11). When the information collection for the small area B is completed, the bright spot information for all the small areas is collected in the order of the arrows shown in FIG. 5 (S12).

<Inspection Method and Apparatus According to Second Embodiment>
Next, the configuration of the inspection apparatus according to the second embodiment will be described with reference to FIG. The description will focus on the differences from the first embodiment described in FIG. In this inspection apparatus, a mechanism for detecting an appropriate rotational position of the inspection phase difference filter 3 (hereinafter, this mechanism is referred to as a sub optical system, and the same mechanism as that in the first embodiment is referred to as a main optical system). It is prepared separately. That is, a second inspection light source 2A, a second inspection phase difference filter 3A, and a second inspection polarization filter 4A are provided. These include the first inspection light source 2, the first inspection phase difference filter 3, and the first inspection phase difference filter 3. Exactly the same one as the polarizing filter 4 for inspection is used. Further, the motor 25A for rotationally driving the second inspection phase difference filter 3A and the intermediate gear 26A are exactly the same as the motor 25 for driving the first inspection phase difference filter 3 and the intermediate gear 26. is there.

  Unlike the main optical system, the sub optical system does not include the photographing camera 5, but is provided with a photodiode 5A (corresponding to a light receiving means) instead. Since the sub optical system is for detecting the rotational position of the inspection phase difference filter 3A, it is not necessary to capture image data, and it is sufficient that only brightness data can be acquired.

  The first and second stages 21 and 22 are controlled so as to be movable to the main optical system side and the sub optical system side. Therefore, the laminated film 1 to be inspected is also the main optical system side and the sub optical system side. Is controlled to be movable.

<Control function>
FIG. 8 is a block diagram illustrating a control function of the inspection apparatus according to the second embodiment. A description will be given centering on differences from those described in FIG. The FD control unit 40 controls the operation of the photodiode 5A. The phase difference filter control unit 33 (corresponding to the filter position detection means) also has a function of giving a command to the motor 25A and controlling the rotation of the second inspection phase difference filter 3A.

  The brightness determination unit 38 has a function of determining the most appropriate rotation position of the inspection phase difference filter 3 based on the light amount data of the transmitted light acquired while rotating the second inspection phase difference filter 3. Specifically, it has a function of finding the rotational position where the transmitted light is absorbed most, that is, the rotational position where the transmitted light amount is determined to be the smallest, while rotating the second inspection phase difference filter 3.

  The storage means 39 stores the rotational position found as described above and the corresponding small area in association with each other. The phase difference filter control unit 33 (corresponding to the filter rotation position control means) can control the rotation position of the first inspection phase difference filter 3 based on the stored rotation position data.

  The stages 21 and 22 and the stage controller 34 function as main filter position setting means and sub filter position setting means.

<Inspection procedure>
Next, the inspection procedure by the inspection apparatus according to the second embodiment will be described with reference to the flowcharts of FIGS. The divided small area 1a of the laminated film 1 is the same as that shown in FIG. The order of inspection is indicated by A → B → C →... EE → FF as indicated by arrows.

  As shown in the flowchart of FIG. 9, first, the laminated film 1 to be inspected is mounted on the first stage 21, and the stages 21 and 22 are set to the sub optical system (S21). Thereby, the laminated film 1 is set at a predetermined position of the sub optical system.

  Next, the stages 21 and 22 are driven so that the optical axis L is positioned at the center of the small area A of the laminated film 1 (S22). Next, the second inspection polarizing filter 4A is arranged so as to be in a crossed Nicols state (S23). The position of the second inspection polarizing filter 4A is fixed until the inspection of one laminated film 1 is completed.

  Next, the second inspection phase difference filter 3A is rotated 360 °, and the transmitted light amount data of the small region A is acquired by the photodiode 5A (S24). The second inspection phase difference filter 3A may be rotated at least 360 °, and can be continuously rotated. A signal representing the rotational position is also taken in conjunction with the rotational operation of the second inspection phase difference filter 3A. Thereby, data can be acquired in a state where the rotation position and the transmitted light amount are associated with each other.

  From the obtained transmitted light amount data, the rotation position where the transmitted light is weakest is determined by the function of the brightness determination unit 38 (S25). The obtained rotational position is stored in the storage means 39 in association with data (identification information) for specifying the small area A. Next, the first and second stages 21 and 22 are moved to repeat the same operation for the small region B (S26). Thereafter, the rotational position data for each small area is acquired in the order of A → B → C →... EE → FF, and stored in the storage means 39 (S27).

  Next, the first and second stages 21 and 22 are moved and set so that the optical axis L of the main optical system is located at the center of the small area A of the laminated film 1 (S28, S29). Next, the first inspection polarizing filter 4 is set to be in a crossed Nicols state (S30). The position of the first inspection polarizing filter 4 is fixed until the inspection of one laminated film 1 is completed.

  Next, the rotation position data for the small region A is read out of the data already acquired in S27, and the first inspection phase difference filter 3 is set at the rotation position (S31). When the setting is completed, the transmitted light image of the small area A of the laminated film 1 is captured by the photographing camera 5 (S32). Then, the presence / absence of a bright spot in the transmitted light image data is determined, and bright spot information in the small area A is acquired (S33, S34). This is the same as in the first embodiment.

  When all the collection of bright spot information in the small area A is acquired, the first and second stages 21 and 22 are moved, and the same operation for the small area B is repeated (S35). When the information collection for the small area B is completed, the bright spot information for all the small areas is collected in the order of the arrows shown in FIG. 5 (S36).

<Experimental result>
Next, an inspection method according to the present invention (a method in which the phase difference filter is divided into small regions and the phase difference filter is rotated to a position where transmitted light is most absorbed) and a comparative example (a method in which the phase difference filter is not rotated) are tested. The effect was confirmed. The inspection apparatus used in the experiment is that of the second embodiment shown in FIG.

  First, a sample laminated film will be described. As the laminated film, 90 sheets of PFILV0012TPZZ (6.5 inches) manufactured by Nitto Denko Corporation were used. The separator used was Toray's therapy (product number MDA (PR) thickness 38 μm). As the photographing camera 5, an area sensor camera (model number XC-75 (768 × 494 pixels)) manufactured by SONY was used. A photodiode (model number S2281) manufactured by Hamamatsu Photonics was used as the photodiode 5A. As the inspection light sources 2 and 2A, LED lighting (HLV24RD-NR) manufactured by CCS was used. The measurement wavelength range of this light source was peak wavelength: 640 nm, half width: 25 nm.

  The distance between the inspection light source 2A and the sample in the sub optical system was set to 55 mm. The distance between the sample and the photodiode in the sub optical system was set to 360 mm. The distance between the inspection light source 2 and the sample in the main optical system was set to 55 mm. The distance between the sample and the camera in the main optical system was set to 65 mm. The lens used for the photographing camera 5 of the main optical system was a product manufactured by MORITEX (MML1-65D).

Have an appearance inspector visually inspect the 90 samples with the separator peeled off in the dark room with transmitted light, and calculate the detection rate by the inspection method of the present invention and the comparative example with the result as a true value (100%) did. That is,
Detection rate = number of defects detected / number of defects detected by inspector x 100%
Missed rate = number of misses / number of defects detected by inspectors x 100%
It was.

  As a result, the detection rate in the comparative example was 64.0% and the miss rate was 36.0%, whereas the detection rate according to the present invention was 95.6% and the miss rate was 4.4%. . Therefore, according to the inspection method of the present invention, it was confirmed experimentally that the detection rate was greatly improved.

<Specific examples of laminated film>
Although the example which has the polarizing plate 16 was mentioned as an example of the laminated | multilayer film 1 handled in this invention, the more specific structural example is demonstrated. The polarizing plate is formed in a long strip shape, and individual size polarizing plates are obtained by punching from a film-shaped polarizing plate original. The original polarizing plate can be obtained, for example, by pasting, for example, a TAC film (protective film) on both the front and back surfaces of a PVA film (polarizer) manufactured in advance. It is necessary to detect defects (scratches, foreign matter, etc.) present on the surface or inside of the polarizing plate original fabric N having a multilayer structure.

  The original polarizing plate N is (A) a step of drying a polyvinyl alcohol film subjected to dyeing, crosslinking and stretching treatment to obtain a polarizer, and (B) a step of attaching a protective layer to one side or both sides of the polarizer. (C) The process which heat-processes after bonding, and is manufactured by the manufacturing method containing.

  Each treatment of dyeing, crosslinking and stretching of the polyvinyl alcohol film need not be performed separately and may be performed simultaneously, and the order of the treatments may be arbitrary. In addition, you may use the polyvinyl alcohol-type film which gave the swelling process as a polyvinyl-alcohol-type film. Generally, a polyvinyl alcohol film is immersed in a solution containing iodine or a dichroic dye, dyed by adsorbing iodine or a dichroic dye, washed, and stretched in a solution containing boric acid or borax. After uniaxial stretching at a magnification of 3 to 7 times, it is dried. After stretching in a solution containing iodine or dichroic dye, further stretching (two-stage stretching) in a solution containing boric acid or borax, etc., and then drying, the orientation of iodine increases, and the degree of polarization This is particularly preferable because the characteristics are improved.

  Examples of the polyvinyl alcohol polymer include those obtained by polymerizing vinyl acetate and then saponifying vinyl acetate and a small amount of a copolymerizable monomer such as unsaturated carboxylic acid, unsaturated sulfonic acid, and cationic monomer. Polymerized products and the like can be mentioned. The average degree of polymerization of the polyvinyl alcohol polymer is not particularly limited, and any one can be used, but 1000 or more is preferable, and 2000-5000 is more preferable. Moreover, 85 mol% or more is preferable and, as for the saponification degree of a polyvinyl alcohol-type polymer, More preferably, it is 98-100 mol%.

  The thickness of the manufactured polarizer is generally 5 to 80 μm, but is not limited thereto, and the method for adjusting the thickness of the polarizer is not particularly limited. Ordinary methods such as roll stretching and rolling can be used.

  The adhesion treatment between the polarizer and the polarizer protective film as the protective layer is not particularly limited, for example, an adhesive made of vinyl alcohol polymer, or boric acid or borax, glutaraldehyde or melamine, It can be carried out through an adhesive comprising at least a water-soluble crosslinking agent of a vinyl alcohol polymer such as oxalic acid. Such an adhesive layer is formed as a coating / drying layer or the like of an aqueous solution. When preparing the aqueous solution, other additives and a catalyst such as an acid can be blended as necessary.

  An appropriate transparent film can be used for the polarizer protective film provided on one side or both sides of the polarizer. Among them, a film made of a polymer excellent in transparency, mechanical strength, thermal stability, moisture shielding property, etc. is preferably used. Examples of the polymer include acetate resins such as triacetyl cellulose, polycarbonate resins, polyarylate, polyester resins such as polyethylene terephthalate, polyimide resins, polysulfone resins, polyethersulfone resins, polystyrene resins, polyethylene, polypropylene. And other polyolefin resins, polyvinyl alcohol resins, polyvinyl chloride resins, polynorbornene resins, polymethyl methacrylate resins, liquid crystal polymers, and the like. The film may be produced by any of the casting method, calendar method, and extrusion method.

  Moreover, the polymer film described in JP-A-2001-343529 (WO01 / 37007), for example, (A) a thermoplastic resin having a substituted and / or unsubstituted imide group in the side chain, and (B) a substitution in the side chain And / or a resin composition containing an unsubstituted phenyl and a thermoplastic resin having a nitrile group. A specific example is a film of a resin composition containing an alternating copolymer composed of isobutylene and N-methylmaleimide and an acrylonitrile / styrene copolymer. As the film, a film made of a mixed extruded product of the resin composition or the like can be used. Since these films have a small phase difference and a small photoelastic coefficient, problems such as unevenness due to the distortion of the polarizing plate can be eliminated, and since the moisture permeability is small, the humidification durability is excellent.

  Moreover, it is preferable that a polarizer protective film has as little color as possible. Therefore, Rth = [(nx + ny) / 2−nz] · d (where nx and ny are the main refractive index in the plane of the film, nz is the refractive index in the film thickness direction, and d is the film thickness). A protective film having a retardation value in the film thickness direction of −90 nm to +90 nm is preferably used. By using a film having a thickness direction retardation value (Rth) of −90 nm to +90 nm, the coloring (optical coloring) of the polarizing plate caused by the polarizer protective film can be almost eliminated. The thickness direction retardation value (Rth) is more preferably −80 nm to +80 nm, and particularly preferably −70 nm to +70 nm.

  From the viewpoints of polarization characteristics and durability, an acetate resin such as triacetyl cellulose is preferable, and a triacetyl cellulose film whose surface is saponified with an alkali or the like is particularly preferable. In addition, when providing a polarizer protective film on both sides of a polarizer, you may use the polarizer protective film which consists of a polymer which is different in the front and back. The thickness of the polarizer protective film is arbitrary, but is generally 500 μm or less, preferably 1 to 300 μm, particularly preferably 5 to 200 μm for the purpose of thinning the polarizing plate.

  The retardation layer to be laminated on the polarizing plate may be an optical layer having a retardation. Examples of the retardation layer include a polymer coating / drying layer, a liquid crystal molecule orientation fixing layer, and a binder layer. And a polymer film such as a phase difference plate or a temporary attachment film attached through the film. The present invention is particularly preferably applied to the inspection of a laminated film in which a retardation layer having a large retardation variation is laminated in the film plane. As a retardation layer having a large retardation variation, an adhesive is provided to the polarizing plate. An example is a polarizing plate protective film that is laminated with a temporarily attached separator or an adhesive and is temporarily attached to protect the surface of the polarizing plate. Films temporarily attached to these polarizing plates are generally used at the time of transportation, and are films that are peeled off when mounting the polarizing plates. Therefore, the retardation variation in the film plane is not so strictly controlled. . Therefore, it is relatively difficult to inspect defects of the polarizing plate on which such a temporary film is laminated.

  The phase difference variation can be represented by molecular orientation angle variation. The variation in the orientation angle is an index representing how far the desired orientation angle of the molecule controlling the phase difference of the retardation layer is deviated, but the present invention has a retardation layer having an orientation angle variation of 6 ° or more. The present invention can be preferably applied also to a laminated film, and enables a highly accurate inspection. The variation in the orientation angle may be obtained by, for example, measuring the orientation angle of about 3 to 6 points evenly in the width direction of the film and obtaining the difference between the maximum value and the minimum value. For example, it can be measured using KOBRA-21ADH manufactured by Oji Scientific Instruments.

  The polarizer protective film may be subjected to a treatment for the purpose of hard coat treatment, antireflection treatment, sticking prevention, diffusion or antiglare, etc., as long as the object of the present invention is not impaired. The hard coat treatment is performed for the purpose of preventing scratches on the surface of the polarizing plate. For example, a hard coating with an appropriate UV curable resin such as a silicone type is applied to the surface of the transparent protective film. It can be formed by a method to be added to.

  On the other hand, the antireflection treatment is performed for the purpose of preventing reflection of external light on the surface of the polarizing plate, and can be achieved by forming an antireflection film or the like according to the prior art. Anti-sticking is used for the purpose of preventing adhesion to the adjacent layer, and anti-glare treatment is performed for the purpose of preventing external light from being reflected on the surface of the polarizing plate and obstructing the visibility of the light transmitted through the polarizing plate. For example, it can be formed by imparting a fine concavo-convex structure to the surface of the transparent protective film by an appropriate method such as a roughening method by a sandblasting method or an embossing method, or a blending method of transparent fine particles.

  The laminated film according to the present invention can be used as an optical film by laminating various optical layers in practical use. The optical layer is not particularly limited, for example, on the surface of the transparent protective film that does not adhere the polarizer (the surface on which the adhesive coating layer is not provided), hard coat treatment or antireflection treatment, Examples thereof include a method of applying a surface treatment for the purpose of preventing sticking, diffusion or antiglare, and laminating an alignment liquid crystal layer for the purpose of viewing angle compensation or the like. Further, an optical film used for forming a liquid crystal display device such as a reflection plate, a semi-transmission plate, a phase difference plate (including a wave plate (λ plate) such as 1/2 or 1/4), a viewing angle compensation film, etc. A layer or a laminate of two or more layers is also included. In particular, if the sheet-like product is a polarizing plate, a reflective polarizing plate or a semi-transmissive polarizing plate in which a reflecting plate or a semi-transmissive reflecting plate is laminated, an elliptical polarizing plate or a circular polarizing plate in which a retardation plate is laminated, It is preferably applied as a wide viewing angle polarizing plate in which a viewing angle compensation layer or a viewing angle compensation film is laminated, or a polarizing plate in which a brightness enhancement film is laminated.

  A reflective polarizing plate is a polarizing plate provided with a reflective layer, and is used to form a liquid crystal display device or the like that reflects incident light from the viewing side (display side). Such a light source can be omitted, and the liquid crystal display device can be easily thinned. The reflective polarizing plate can be formed by an appropriate method such as a method in which a reflective layer made of metal or the like is attached to one surface of the polarizing plate via a transparent protective layer or the like as necessary.

  The semi-transmissive polarizing plate can be obtained by using a semi-transmissive reflective layer such as a half mirror that reflects and transmits light with the reflective layer. A transflective polarizing plate is usually provided on the back side of a liquid crystal cell, and displays an image by reflecting incident light from the viewing side (display side) when a liquid crystal display device is used in a relatively bright atmosphere. In a relatively dark atmosphere, a liquid crystal display device or the like that displays an image using a built-in light source such as a backlight built in the back side of the transflective polarizing plate can be formed. In other words, the transflective polarizing plate is useful for forming a liquid crystal display device of a type that can save energy of using a light source such as a backlight in a bright atmosphere and can be used with a built-in light source even in a relatively dark atmosphere. It is.

  An elliptically polarizing plate or a circularly polarizing plate in which a retardation plate is further laminated on a polarizing plate will be described. A phase difference plate or the like is used when changing linearly polarized light to elliptically polarized light or circularly polarized light, changing elliptically polarized light or circularly polarized light to linearly polarized light, or changing the polarization direction of linearly polarized light. In particular, a so-called quarter-wave plate (also referred to as a λ / 4 plate) is used as a retardation plate that changes linearly polarized light into circularly polarized light or changes circularly polarized light into linearly polarized light. A half-wave plate (also referred to as a λ / 2 plate) is usually used when changing the polarization direction of linearly polarized light.

  The elliptically polarizing plate is effectively used for black and white display without the above color by compensating (preventing) the coloration (blue or yellow) generated by the birefringence of the liquid crystal layer of the super twist nematic (STN) type liquid crystal display device. It is done. Further, the one in which the three-dimensional refractive index is controlled is preferable because it can compensate (prevent) coloring that occurs when the screen of the liquid crystal display device is viewed from an oblique direction. The circularly polarizing plate is effectively used, for example, when adjusting the color tone of an image of a reflective liquid crystal display device in which an image is displayed in color, and also has an antireflection function.

  Examples of the retardation plate include a refracting film formed by uniaxially or biaxially stretching a polymer material, a liquid crystal polymer alignment film, and a liquid crystal polymer alignment layer supported by a film. The stretching treatment can be performed by, for example, a roll stretching method, a long gap stretching method, a tenter stretching method, a tubular stretching method, or the like. In the case of uniaxial stretching, the stretching ratio is generally about 1.1 to 3 times. The thickness of the retardation plate is not particularly limited, but is generally 10 to 200 μm, preferably 20 to 100 μm.

  Examples of the polymer material include polyvinyl alcohol, polyvinyl butyral, polymethyl vinyl ether, polyhydroxyethyl acrylate, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, polycarbonate, polyarylate, polysulfone, polyethylene terephthalate, polyethylene naphthalate, and polyethersulfone. , Polyphenylene sulfide, polyphenylene oxide, polyallylsulfone, polyvinyl alcohol, polyamide, polyimide, polyolefin, polyvinyl chloride, cellulosic polymers, or binary, ternary various copolymers, graft copolymers, Examples include blends. These polymer materials become oriented products (stretched films) by stretching or the like.

  Examples of the liquid crystal polymer include various main chain types and side chain types in which a conjugated linear atomic group (mesogen) imparting liquid crystal alignment is introduced into the main chain or side chain of the polymer. It is done. Specific examples of the main chain type liquid crystalline polymer include, for example, a nematic alignment polyester liquid crystalline polymer, a discotic polymer, and a cholesteric polymer having a structure in which a mesogen group is bonded to a spacer portion that imparts flexibility. . Specific examples of the side chain type liquid crystalline polymer include polysiloxane, polyacrylate, polymethacrylate, or polymalonate as a main chain skeleton, and a nematic alignment imparting paraffin through a spacer portion composed of a conjugated atomic group as a side chain. Examples thereof include those having a mesogen moiety composed of a substituted cyclic compound unit. These liquid crystalline polymers are prepared by, for example, applying a solution of a liquid crystalline polymer on an alignment-treated surface such as a surface of a thin film such as polyimide or polyvinyl alcohol formed on a glass plate, or an oblique deposition of silicon oxide. This is done by developing and heat treatment.

  The retardation plate may have an appropriate retardation according to the purpose of use, such as those for the purpose of compensating for various wavelength plates or birefringence of the liquid crystal layer, viewing angle, and the like. What laminated | stacked the phase difference plate and controlled optical characteristics, such as phase difference, etc. may be used.

  A polarizing plate obtained by bonding a polarizing plate and a brightness enhancement film is usually provided on the back side of a liquid crystal cell. The brightness enhancement film reflects a linearly polarized light with a predetermined polarization axis or a circularly polarized light in a predetermined direction when natural light is incident due to a backlight such as a liquid crystal display device or reflection from the back side, and transmits other light. In addition, a polarizing plate in which a brightness enhancement film is laminated with a polarizing plate allows light from a light source such as a backlight to enter to obtain transmitted light in a predetermined polarization state, and reflects light without transmitting the light other than the predetermined polarization state. The The light reflected on the surface of the brightness enhancement film is further inverted through a reflective layer or the like provided behind the brightness enhancement film and re-incident on the brightness enhancement film, and part or all of the light is transmitted as light having a predetermined polarization state. Luminance can be improved by increasing the amount of light transmitted through the enhancement film and increasing the amount of light that can be used for liquid crystal display image display or the like by supplying polarized light that is difficult to be absorbed by the polarizer.

  Further, the laminated film of the present invention may be composed of a laminate of a polarizing plate and two or more optical layers, such as the above-described polarization separation type polarizing plate. Therefore, a reflective elliptical polarizing plate or a semi-transmissive elliptical polarizing plate in which the above-mentioned reflective polarizing plate or transflective polarizing plate and a retardation plate are combined may be used.

  An optical film in which the optical layer is laminated on a polarizing plate can be formed by a method of sequentially laminating separately in the manufacturing process of a liquid crystal display device or the like. There is an advantage that the manufacturing process of a liquid crystal display device or the like can be improved because of excellent stability and assembly work. For the lamination, an appropriate adhesive means such as a pressure-sensitive adhesive layer can be used. When adhering the polarizing plate and the other optical layer, their optical axes can be set at an appropriate arrangement angle in accordance with the target phase difference characteristic.

  The polarizing plate according to the present invention and the laminated optical member may be provided with an adhesive layer for bonding with other members such as a liquid crystal cell. The pressure-sensitive adhesive layer is not particularly limited, but can be formed with a suitable pressure-sensitive adhesive according to the conventional type such as acrylic. Low moisture absorption and heat resistance due to prevention of foaming and peeling phenomenon due to moisture absorption, deterioration of optical characteristics due to thermal expansion difference, prevention of liquid crystal cell warpage, and formation of a high-quality and durable image display device. It is preferable that it is an adhesive layer excellent in property. Moreover, it can be set as the adhesion layer etc. which contain microparticles | fine-particles and show light diffusivity. The adhesive layer may be provided on a necessary surface as necessary. For example, when referring to a polarizing plate comprising a polarizer and a protective film, an adhesive layer may be provided on one or both sides of the protective film as necessary. That's fine.

  The exposed surface of the adhesive layer is temporarily covered with a separator for the purpose of preventing contamination until it is put into practical use. Thereby, it can prevent contacting an adhesion layer in the usual handling state. As the separator, easy-peeling performance and translucency, such as those obtained by coating a translucent plastic film such as polyester or polyethylene terephthalate with an appropriate release agent such as silicone-based, long-chain alkyl-based, fluorine-based or molybdenum sulfide, etc. Any suitable one according to the prior art having performance can be used. In addition, on the surface of the laminated film that does not have an adhesive layer, an easy-peelable protective film in which the adhesive layer is laminated on the translucent plastic film as described above is temporarily attached to protect the laminated film. Also good.

  In the present invention, the polarizer, transparent protective film, optical film, and the like that form the polarizing plate described above, and each layer such as an adhesive layer include, for example, salicylic acid ester compounds, benzophenol compounds, benzotriazole compounds, and cyanoacrylates. It may be a compound having an ultraviolet absorbing ability by a method such as a method of treating with an ultraviolet absorber such as a compound based on nickel or a nickel complex salt compound.

The laminated film according to the present invention can be preferably used for forming an image display device such as a liquid crystal display device, an organic EL display device, and a PDP.
The polarizing plate or the optical film of the present invention can be preferably used for forming various devices such as a liquid crystal display device. The liquid crystal display device can be formed according to the conventional method. In other words, a liquid crystal display device is generally formed by appropriately assembling components such as a liquid crystal cell, a polarizing plate or an optical film, and an illumination system as necessary, and incorporating a drive circuit. There is no limitation in particular except the point which uses the polarizing plate or optical film by invention, and it can apply according to the former. As the liquid crystal cell, any type such as a TN type, an STN type, or a π type can be used.

  An appropriate liquid crystal display device such as a liquid crystal display device in which a polarizing plate or an optical film is disposed on one side or both sides of a liquid crystal cell, or a backlight or a reflector used in an illumination system can be formed. In that case, the polarizing plate or optical film by this invention can be installed in the one side or both sides of a liquid crystal cell. When providing a polarizing plate or an optical film on both sides, they may be the same or different. Further, when forming a liquid crystal display device, for example, a single layer or a suitable part such as a diffusing plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusing plate, a backlight, etc. Two or more layers can be arranged.

  Next, an organic electroluminescence device (organic EL display device) will be described. Generally, in an organic EL display device, a transparent electrode, an organic light emitting layer, and a metal electrode are sequentially laminated on a transparent substrate to form a light emitter (organic electroluminescent light emitter). Here, the organic light emitting layer is a laminate of various organic thin films, for example, a laminate of a hole injection layer made of a triphenylamine derivative and the like and a light emitting layer made of a fluorescent organic solid such as anthracene, Alternatively, a structure having various combinations such as a laminate of such a light-emitting layer and an electron injection layer composed of a perylene derivative or the like, or a laminate of these hole injection layer, light-emitting layer, and electron injection layer is known. It has been.

  In an organic EL display device comprising an organic electroluminescent light emitting device comprising a transparent electrode on the surface side of an organic light emitting layer that emits light upon application of a voltage and a metal electrode on the back side of the organic light emitting layer, the surface of the transparent electrode While providing a polarizing plate on the side, a retardation plate can be provided between the transparent electrode and the polarizing plate.

  Since the retardation plate and the polarizing plate have a function of polarizing light incident from the outside and reflected by the metal electrode, there is an effect that the mirror surface of the metal electrode is not visually recognized by the polarization action. In particular, the mirror surface of the metal electrode can be completely shielded by configuring the retardation plate with a quarter-wave plate and adjusting the angle formed by the polarization direction of the polarizing plate and the retardation plate to π / 4. .

  The laminated film according to the present invention can be preferably used for forming various devices such as a liquid crystal display device. The liquid crystal display device has an appropriate structure according to the conventional transmission type, reflection type, or transmission / reflection type in which the laminated film (for example, polarizing plate) according to the present invention is disposed on one side or both sides of the liquid crystal cell. Can be formed as Accordingly, the liquid crystal cell forming the liquid crystal display device is arbitrary, and for example, a liquid crystal cell of an appropriate type such as a simple matrix driving type typified by a thin film transistor type may be used.

<Another embodiment>
In the present embodiment, the laminated film 1 is configured to move in the XY plane by the stages 21 and 22, but the main optical system and the non-optical system are moved without moving the laminated film 1. You may comprise. Either case is included in the present invention.

  The order in which the inspection area of the laminated film is divided into small areas and the small areas are inspected is not limited to the order shown in FIG. 5, and various modifications are possible.

It is the schematic which shows the structure of an inspection apparatus and an inspection method. Diagram showing the structure of laminated film The conceptual diagram which shows the structure of the inspection apparatus of the laminated | multilayer film concerning 1st Embodiment. The block diagram which shows the control function of the inspection apparatus shown in FIG. The figure which shows the divided | segmented small area | region of a laminated | multilayer film The flowchart which shows the procedure of the inspection method which concerns on 1st Embodiment. The conceptual diagram which shows the structure of the test | inspection apparatus of the laminated film concerning 2nd Embodiment. The block diagram which shows the control function of the inspection apparatus shown in FIG. The flowchart which shows the procedure of the inspection method which concerns on 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laminated film 1a Small area | region 2,2A Inspection light source 3,3A Inspection phase difference filter 4,4A Inspection polarizing filter 5 Photographing camera 5A Photodiode 11 Separator 12 Adhesive layer 13 Protective layer 14 Polarizer 15 Phase difference film 21 First stage 22 Second stage 30 Computer 31 Controller 32 Camera control unit 33 Phase difference filter control unit 34 Stage control unit 38 Brightness determination unit 39 Storage means L Optical axis

Claims (8)

At least, when performing defect detection of a laminated film in which a polarizer and a retardation layer are laminated,
A method for inspecting a laminated film comprising: irradiating a laminated film using a light source for inspection; and photographing a transmitted light image from the light source for inspection through a polarizing filter for inspection and a phase difference filter for inspection. There,
The inspection area of the laminated film is set to be divided into a plurality of small areas, and the step of positioning the inspection polarizing filter and the inspection phase difference filter for each area;
Rotating the positioned inspection phase filter to detect the rotational position where the transmitted light is most absorbed,
A method for inspecting a laminated film at a detected rotational position, and taking a transmitted light image of the small region.   The rotation angle range of the phase difference filter for inspection is set in advance, and the rotation position is detected while being moved by a predetermined angle pitch within the angle range. Film inspection method.   The method for inspecting a laminated film according to claim 1 or 2, wherein the irradiation light from the inspection light source has a center wavelength of 600 to 700 nm and a half width of 50 nm or less. At least, when performing defect detection of a laminated film in which a polarizer and a retardation layer are laminated,
A laminated film inspection apparatus comprising: an inspection light source that irradiates a laminated film; and an imaging unit that photographs a transmitted light image from the inspection light source through an inspection polarizing filter and an inspection phase difference filter,
The inspection area of the laminated film is divided and set into a plurality of small areas, and filter position setting means for positioning the inspection polarizing filter and the inspection phase difference filter for each area,
And a filter position detecting means for detecting the rotational position where the transmitted light is most absorbed by rotating the inspection phase difference filter positioned,
An apparatus for inspecting a laminated film, wherein the transmitted light image of the small area is photographed by the photographing means at the detected rotational position. At least, when performing defect detection of a laminated film in which a polarizer and a retardation layer are laminated,
Irradiating the laminated film using the first inspection light source, and photographing the transmitted light image from the first inspection light source through the first inspection polarizing filter and the first inspection phase difference filter; And having
Furthermore, the step of irradiating the laminated film using the second inspection light source, and the step of receiving the transmitted light from the second inspection light source through the second inspection polarizing filter and the second inspection phase difference filter, A method for inspecting a laminated film comprising:
The inspection area of the laminated film is divided and set into a plurality of small areas, and the second inspection polarizing filter and the second inspection retardation filter are positioned for each area;
Rotating the positioned second inspection phase difference filter to detect a rotational position where transmitted light is most absorbed;
Storing the detected rotational position for each small region;
Positioning the first inspection polarizing filter and the first inspection phase difference filter for each region;
Setting the rotational position of the first inspection phase difference filter based on the stored rotational position;
After setting the first inspection phase difference filter, a step of photographing the transmitted light image of the small region.   6. The method for inspecting a laminated film according to claim 5, wherein the irradiation light from the first inspection light source has a center wavelength of 600 to 700 nm and a half width of 50 nm or less.   The method for inspecting a laminated film according to claim 5 or 6, wherein the rotation angle of the second inspection phase difference filter is at least 360 °, and the received light is received by a photodiode. At least, when performing defect detection of a laminated film in which a polarizer and a retardation layer are laminated,
A first inspection light source that irradiates the laminated film, and an imaging unit that captures a transmitted light image from the first inspection light source through the first inspection polarization filter and the first inspection phase difference filter. ,
And a second inspection light source for irradiating the laminated film, and a light receiving means for receiving the transmitted light from the second inspection light source through the second inspection polarization filter and the second inspection phase difference filter. An inspection device for laminated film,
Sub-filter position setting means for setting the inspection area of the laminated film to be divided into a plurality of small areas, and positioning the second inspection polarizing filter and the second inspection phase difference filter for each area;
A filter position detecting means for rotating the positioned second inspection phase difference filter to detect a rotational position where the transmitted light is most absorbed;
Storage means for storing the detected rotational position for each small region;
Main filter position setting means for positioning the first inspection polarizing filter and the first inspection phase difference filter for each region;
Filter rotation position control means for setting the rotation position of the first inspection phase difference filter based on the stored rotation position,
An inspection apparatus for a laminated film, wherein after setting the first inspection phase difference filter, the transmitted light image of the small area is imaged by the imaging means.

Images