KR102386369B1 - Polarizing plate inspection method and inspection apparatus - Google Patents

Abstract

[Problem] To provide a method for preferably inspecting the appearance of a long polarizing plate having non-polarizing portions arranged at predetermined intervals in the long picture direction.
[Solution means] A method of inspecting the appearance of a long polarizing plate having non-polarizing portions arranged at predetermined intervals in the long picture direction while conveying it in the long picture direction, the step of imaging the polarizing plate to acquire image data, and the image An inspection method, comprising: a step of analyzing data to extract a candidate defect portion; a step of determining whether the defect candidate portion has a size equal to or less than a reference value; and a step of detecting a defect based on the size of the defect candidate portion.

Description

Inspection method and inspection apparatus of a polarizing plate

The present invention relates to an inspection method and an inspection apparatus for a polarizing plate having a non-polarization part. Representatively, it relates to the inspection method and inspection apparatus of the polarizing plate containing the polarizer which has a non-polarization part.

DESCRIPTION OF RELATED ART Some image display apparatuses, such as a cellular phone and a notebook personal computer (PC), are equipped with internal electronic components, such as a camera. For the purpose of improving the camera performance of such an image display apparatus, etc., various examination is made|formed (for example, patent documents 1-7). However, with the rapid spread of smart phones and touch panel type information processing devices, it is desired that camera performance and the like be further improved. Moreover, in order to respond to the diversification of the shape of an image display apparatus, and high functionalization, the polarizing plate which has polarization performance partially is desired. In order to realize these demands industrially and commercially, it is desired to manufacture an image display device and/or its parts at an acceptable cost, and various considerations remain in order to establish such a technology.

Japanese Patent Laid-Open No. 2011-81315 Japanese Laid-Open Patent Publication No. 2007-241314 Specification of US Patent Application Publication No. 2004/0212555 Korean Patent Publication No. 10-2012-0118205 Korean Patent Publication No. 10-1293210 Japanese Patent Laid-Open No. 2012-137738 Specification of US Patent Application Publication No. 2014/0118826

When the present inventors partially produced a polarizing plate using a polarizer having a non-polarization part as a polarizing plate having polarization performance, and subjected the obtained polarizing plate to an appearance inspection, they encountered a problem that the non-polarization part was erroneously detected as a defect. The present invention has been made in order to solve the problem, and its main object is a method for preferably inspecting the appearance of a long polarizing plate having a non-polarizing part arranged at predetermined intervals in a long direction, including a polarizer having a non-polarizing part is to provide

ADVANTAGE OF THE INVENTION According to this invention, the method of inspecting the external appearance is provided, conveying the elongate polarizing plate which has a non-polarization part arrange|positioned at predetermined intervals in the direction of a long picture, conveying in the direction of a long picture. The inspection method includes a step of acquiring image data by imaging the polarizing plate, a step of analyzing the image data to extract a defect candidate portion, a step of determining whether the defect candidate portion has a size equal to or less than a reference value; and a step of detecting a defect based on the size of the defect candidate portion.

In one embodiment, the said polarizing plate has the non-polarization part arrange|positioned at predetermined intervals in the elongate direction and the width direction.

In one embodiment, acquisition of the said image data is performed based on continuous imaging of the said polarizing plate.

In one embodiment, extraction of the said defect candidate part is performed based on the brightness|luminance information of the said image data.

In one embodiment, further comprising the process of determining whether the said defect candidate part has periodicity in the said long direction, The process of detecting the said defect is a defect based on the size of the said defect candidate part, and the presence or absence of periodicity. is the process of detecting

In one Embodiment, it is judged whether it has periodicity in the said elongate direction only about the defect candidate part which has a size exceeding the said reference value.

In one embodiment, determination of the presence or absence of periodicity of the said defect candidate part is performed based on the positional coordinate in the long direction of the said defect candidate part.

In one embodiment, determination of the presence or absence of periodicity of the said defect candidate part is performed based on whether the distance in the long direction of the defect candidate part which is a judgment object, and the non-polarization part which exists upstream in the conveyance direction is a predetermined distance. .

According to another aspect of this invention, the manufacturing method of a polarizing plate is provided. The manufacturing method includes test|inspecting a polarizing plate by the said test|inspection method.

According to another aspect of this invention, the external appearance inspection apparatus of a long polarizing plate is provided. The appearance inspection device includes an imaging device that acquires image data by imaging a long polarizing plate having a non-polarizing portion arranged at predetermined intervals in the direction of a long picture, and an image analysis device that analyzes the image data and detects a defect in the polarizing plate. be prepared The image analysis apparatus includes a defect candidate part extraction unit that extracts a defect candidate unit based on the image data, a size determination unit that determines whether the defect candidate unit has a size equal to or less than a reference value, and a defect candidate unit in the elongate direction It has a periodicity determination unit that determines whether or not periodicity is present, and a defect detection unit that detects defects based on the size of the defect candidate portion or the size of the defect candidate portion and the presence or absence of periodicity.

According to the inspection method of the present invention, since it is possible to avoid erroneous detection of a non-polarization part as a defect, the appearance of a long polarizing plate having a non-polarization part arranged at predetermined intervals in the direction of a long picture including a polarizer having a non-polarization part Preferably, it can be inspected.

1 is a schematic cross-sectional view of a polarizing plate that can be provided in the inspection method of the present invention.
It is a schematic plan view explaining an example of the arrangement pattern of a non-polarization part.
It is a schematic plan view explaining the other example of the arrangement pattern of a non-polarization part.
2C is a schematic plan view illustrating another example of an arrangement pattern of a non-polarization part.
3 is a schematic diagram illustrating an inspection apparatus that can be used in the inspection method of the present invention.
It is a flowchart explaining the specific procedure of defect detection in one Embodiment of this invention.
It is a flowchart explaining the specific procedure of defect detection in another embodiment of this invention.
FIG. 6 is a schematic diagram illustrating a specific procedure of defect detection in the embodiment shown in FIG. 5 .

[A. Inspection method and inspection device]

This invention provides the method of inspecting the external appearance, conveying the elongate polarizing plate which has a non-polarization part arrange|positioned at predetermined intervals in the direction of a long picture, conveying in the direction of a long picture. The inspection method of the present invention includes a step of acquiring image data by imaging a polarizing plate having a non-polarizing portion, a step of analyzing the image data to extract a defect candidate portion, and determining whether the defect candidate portion has a size less than or equal to a reference value and a step of detecting a defect based on the size of the defect candidate portion. In the process of detecting a defect, the defect candidate part which has a size exceeding a reference value is recognized and distinguished as a non-polarization part, for example, and the defect candidate part which has a size less than a reference value can be detected as a defect.

The inspection method of the present invention may further include a step of determining whether the defect candidate portion has periodicity in the long direction. In this case, in the said defect detection process, a defect is detected based on the size of a defect candidate part, and the presence or absence of periodicity. More specifically, a defect candidate portion having a size equal to or less than a reference value is detected as a defect, and a defect candidate portion having no periodicity is also detected as a defect. By evaluating the defect candidate part from two aspects of size and periodicity, inspection precision can be improved. From the viewpoint of inspection efficiency, it is preferable to determine the presence or absence of periodicity only for the defect candidate portions having a size exceeding the reference value. In this case, all the defect candidate parts having a size equal to or less than the reference value are detected as defects, and only those that do not have periodicity are detected as defects in the defect candidate parts having a size exceeding the reference value.

A-1. Polarizer

The polarizing plate provided for the inspection method of this invention is elongate, and has the non-polarization part arrange|positioned at predetermined intervals in the direction of a long picture. The non-polarization part originates in the non-polarization part formed in the polarizer typically. In addition, in this specification, "long shape" means an elongate shape with a length sufficiently long compared to the width, for example, 10 times or more in length compared to the width, preferably 20 times or more elongate shape. include

1 is a schematic cross-sectional view of a polarizing plate that can be provided in the inspection method of the present invention. The polarizing plate 30 has the polarizer 10 which has a non-polarization part, and the protective films 11 and 12 arrange|positioned on the both sides of the polarizer 10. In the example of illustration, although the protective film is arrange|positioned on both sides of a polarizer, the protective film may be arrange|positioned only on one side. Alternatively, the polarizing plate may be composed of only a polarizer (that is, the polarizing plate may be a polarizer).

The polarizer 10 is typically comprised from the resin film containing a dichroic substance. Since the polarizing plate 30 is a long picture, the polarizer 10 is also a long picture. The polarizer 10 has a non-polarization part arrange|positioned at predetermined intervals in the direction of a long picture. In one embodiment, the polarizer 10 has a non-polarization part arrange|positioned at predetermined intervals in the long direction and the width direction. The arrangement pattern of a non-polarization part can be set suitably according to the objective. Typically, when the said non-polarization part cuts to a predetermined size in order to mount a polarizer to the image display apparatus of a predetermined size (for example, cut|disconnection in the long direction and/or the width direction, and punching), It may be disposed at a position corresponding to the camera unit of the image display device. In one Embodiment, a non-polarization part is arrange|positioned at substantially equal intervals also in any direction of a long direction and a width direction. In addition, "substantially equally spaced in either the direction of the long picture and the width direction" means that the intervals in the long direction are equally spaced, and that the intervals in the width direction are equally spaced, and that the intervals in the long direction and the width direction The spacing need not be equal. In another embodiment, a non-polarization part is arrange|positioned at equal intervals substantially in the direction of a long picture, and may be arrange|positioned at the space|interval different in the width direction. When a non-polarization part is arrange|positioned by the space|interval from which a non-polarization part differs in the width direction, all may differ from the space|interval of an adjacent non-polarization part, and only one part (space|interval of a specific adjacent non-polarization part) may differ. Moreover, a some area|region may be prescribed|regulated by the long direction of a polarizer, and the space|interval of the non-polarization part in a long direction and/or the width direction may be set for every area|region.

2A-2C are schematic plan views explaining an example of the arrangement pattern of the non-polarization part in the polarizer 10, respectively. In one embodiment, as for the non-polarization part 10a, as shown to FIG. 2A, the straight line which connects the non-polarization part adjacent in a long direction is substantially parallel with respect to a long direction, And adjacent in the width direction It is arrange|positioned so that the straight line which connects a non-polarization part may be substantially parallel with respect to the width direction.

Any suitable shape can be employ|adopted as for the shape at the time of planar view of a non-polarization part according to the objective. For example, as long as the shape of a non-polarization part in planar view does not adversely affect the camera performance of the image display apparatus in which a polarizer is used, any suitable shape can be employ|adopted. Although the non-polarization part of the example of illustration is circular, you may form, for example in an ellipse, a square, a quadrangle, a rhombus, etc.

The transmittance|permeability (for example, the transmittance|permeability measured with the light of wavelength 550nm in 23 degreeC) of a non-polarization part becomes like this. Preferably it is 50 % or more, More preferably, it is 60 % or more, More preferably, it is 75 % or more. and particularly preferably 90% or more. If it is such a transmittance|permeability, for example, when a polarizer is arrange|positioned so that a non-polarization part may correspond to the camera part of an image display apparatus, the bad influence to the imaging|photography performance of a camera can be prevented.

The non-polarizing portion may be of any suitable shape. In one embodiment, the non-polarization part is the partially decolorized part. The discolored portion is formed by, for example, laser irradiation or chemical treatment. In another embodiment, a non-polarization part is a through-hole. The through hole is formed, for example, by mechanical punching (eg punching, Thomson blade punching, plotter, water jet) or removal of a predetermined portion (eg laser ablation or chemical dissolution).

As a forming material of the protective films 11 and 12, For example, cellulose resins, such as diacetyl cellulose and triacetyl cellulose, (meth)acrylic-type resin, cycloolefin resin, olefin resin, such as polypropylene, polyethylene Ester-type resins, such as a terephthalate-type resin, polyamide-type resin, polycarbonate-type resin, these copolymer resin, etc. are mentioned. One of the protective films 11 and 12 may be abbreviate|omitted according to the objective or desired structure.

The thickness of a protective film is 10 micrometers - 100 micrometers typically. A protective film is typically laminated|stacked on a polarizer via a contact bonding layer (specifically, an adhesive bond layer, an adhesive layer). The adhesive layer is typically formed of a PVA-based adhesive or an active energy ray-curable adhesive. The pressure-sensitive adhesive layer is typically formed of an acrylic pressure-sensitive adhesive.

Practically, the polarizing plate 30 has the adhesive layer 13 as an outermost layer. The pressure-sensitive adhesive layer 13 is typically an outermost layer on the side of the image display device. The separator 14 is temporarily affixed to the adhesive layer 13 so that peeling is possible, and while protecting an adhesive layer until actual use, roll formation is enabled.

The polarizing plate 30 may further have arbitrary appropriate optical function layers according to the objective. As a typical example of an optical function layer, retardation film (optical compensation film) and a surface treatment layer are mentioned. For example, a retardation film may be disposed between the protective film 12 and the pressure-sensitive adhesive layer 13 (not shown). The optical properties of the retardation film (eg, refractive index ellipsoid, in-plane retardation, thickness-direction retardation) can be appropriately set according to the purpose, characteristics of an image display device, and the like.

The surface treatment layer may be disposed on the outside of the protective film 11 (not shown). Representative examples of the surface treatment layer include a hard coat layer, an antireflection layer, and an antiglare layer. It is preferable that a surface treatment layer is a layer with low water vapor transmission rate for the purpose of improving the humidification durability of a polarizer, for example. Instead of forming the surface treatment layer, the surface of the protective film 11 may be subjected to the same surface treatment.

A-2. inspection device

3 is a schematic diagram illustrating an inspection apparatus that can be used in the inspection method of the present invention. In illustrated embodiment, the elongate polarizing plate 30 is conveyed to the inspection apparatus 100, and an external appearance inspection is performed. The inspection apparatus 100 is equipped with the imaging apparatus 50 which acquires image data by imaging the polarizing plate 30, and the image analysis apparatus 80 which analyzes the obtained image data and detects the defect of the polarizing plate 30 do. The image analysis apparatus 80 includes a defect candidate part extraction unit 82 for extracting a defect candidate part based on the obtained image data, and a size judgment part 84 for judging whether the defect candidate part has a size equal to or less than a reference value; , a periodicity determination unit 86 for judging whether the defect candidate portion has periodicity in the long direction, and a defect detection unit 88 for detecting defects based on the size of the defect candidate portion or the size of the defect candidate portion and the presence or absence of periodicity has

A-3. Process of acquiring image data (1)

Process (1) can be performed by imaging the polarizing plate which has the said non-polarization part using the imaging device 50, and obtaining image data. The imaging device 50 typically includes an illumination unit 52 and an imaging unit 54 .

The lighting unit 52 may be constructed using any suitable light source. A white light source may be sufficient as a light source, and a monochromatic light source may be sufficient as it. A fluorescent lamp, a halogen lamp, a metal halide lamp, LED etc. are mentioned as a specific example of a light source.

The imaging unit 54 is typically a camera configured using a lens and an image sensor. One or more imaging units are preferably formed so that the entire width of the polarizing plate can be imaged. Further, the imaging unit is preferably capable of imaging continuous images in the direction of a long picture. In one embodiment, the imaging unit is a line sensor camera.

In embodiment shown in FIG. 3, light is irradiated to the polarizing plate 30 from the illumination part 52 arrange|positioned on one side of the said polarizing plate, so that the other side of the polarizing plate 30 may face the illumination part 52 The light transmitted through the polarizing plate 30 is imaged by the arranged imaging unit 54 . By imaging the transmitted light, an image in which the luminance of the region corresponding to the non-polarization portion is higher than that of the region corresponding to the other part can be obtained.

In another embodiment (not shown), an illumination part and an imaging part are arrange|positioned on one side of the said polarizing plate, light is irradiated with respect to a polarizing plate from the illumination part from the oblique direction, and a polarizing plate by the imaging part arrange|positioned on the same side as the illumination part. The reflected light is imaged.

In another embodiment (not shown), an illumination unit and an imaging unit are arranged on one side of the polarizing plate, and light is irradiated perpendicularly to the polarizing plate so that the optical axis of the camera of the imaging unit and the optical axis of the irradiated light coincide, Reflected light is captured.

By imaging the polarizing plate by selecting an appropriate imaging method according to the shape of the non-polarizing part (discoloration part, through hole, etc.), the configuration of the polarizing plate, etc., the difference between the luminance of the region corresponding to the non-polarizing part and the luminance of the region corresponding to other parts is large (As a result, an image with a large contrast ratio) can be obtained. Imaging of a polarizing plate may be performed according to any one of the said embodiment, and may be performed combining two or more embodiments.

Preferably, imaging is performed, conveying a long polarizing plate in a long direction. By performing imaging while conveying, stoppage of a manufacturing line can be avoided and manufacturing efficiency can be maintained.

A-4. Step (2) for extracting the defect candidate part

The image data obtained by the imaging device 50 is transmitted to the image analysis device 80 as an electric signal. The transmitted image data is analyzed by the defect candidate part extraction unit 82, whereby the defect candidate part is extracted.

In one embodiment, a defect candidate part is extracted based on the luminance information of image data. Specifically, a normal polarizing plate is imaged in advance, a luminance standard determined to be normal is set, and a defect candidate part is extracted based on the reference|standard. For example, a high luminance portion exceeding the upper limit of luminance determined to be normal, a low luminance portion exceeding the lower limit of luminance determined to be normal, or the like can be determined as a defect candidate portion. Defect parts that cause poor appearance, such as foreign substances, bubbles, and pinholes, are usually extracted as defect candidate parts according to the luminance criteria as described above because transmittance, reflectance, etc. are different from the normal region of the polarizing plate. On the other hand, in the obtained image data, the area|region corresponding to a non-polarization part can also be extracted as a defect candidate part at the point which differs from the area|region corresponding to the other part in transmittance|permeability, a reflectance, etc..

The defect candidate extraction unit 82 preferably stores the positional information of the defect candidate unit (for example, positional coordinates (X, Y) in the long direction and the width direction in images continuous in the long direction), and periodicity transmitted to the determination unit 86 .

A-5. Step (3) of judging whether the defect candidate portion has a size equal to or less than a reference value

When a candidate defect part is extracted by the defect candidate part extraction part 82, for each extracted defect candidate part, the size determination part 84 determines the size, and furthermore, whether the size is below a reference value. to judge

Determination of the size of the defect candidate portion may be performed by any suitable method. For example, a size can be determined based on the pixel number, diameter, area, etc. of the defect candidate part in image data. As for the diameter of the defect candidate part, typically, in image data, the length of the longest among straight lines connecting two arbitrary points on the outer periphery of a defect candidate part can be determined as a diameter. The area may be calculated based on the number of pixels or the diameter.

The reference value may be determined by any suitable method. For example, the reference value may be determined based on the size of the non-polarization part. For example, when judging a size by a diameter, the said reference value (standard value of a diameter) can be determined as follows. That is, the diameter (theoretical value) of the non-polarization part is calculated based on the shape and size of the non-polarization part in design, or the diameter (actual value) of the non-polarization part actually formed in the polarizer is measured, and the diameter of the non-polarization part obtained is an example 90 %, Preferably 95 % can be made into the reference value. Further, for example, when the average size of the defects is sufficiently small compared to the size of the non-polarization part (for example, when the average diameter of the defects is 1/8 or less of the diameter of the non-polarization part), the reference value is the diameter of the non-polarization part It can be set to a value of 1/4 to 1/2 of As a specific example, when the diameter of a non-polarization part is about 2800 micrometers and the average diameter of a defect is 150 micrometers - 300 micrometers, the said reference value can be made into about 1000 micrometers.

A-6. Step (4) of judging whether the defect candidate portion has periodicity in the long direction

The periodicity determination unit 86 may use the whole extracted defect candidate portions as the object of determination of periodicity, or may only determine the defect candidate portions confirmed to have a size exceeding the reference value in the size determination portion 84 as the determination object. . Preferably, only the defect candidate part confirmed to have a size exceeding the reference value in the size judgment part 84 is made into judgment object.

In one embodiment, when three or more defect candidate portions exist at equal intervals on a straight line extending in an arbitrary direction, it can be determined that these defect candidate portions have periodicity.

In the polarizing plate of an inspection object, since the non-polarization part is arrange|positioned at least at predetermined intervals in a long picture direction, periodicity can be judged based on the space|interval between the non-polarization parts in a long picture direction. Therefore, the presence or absence of periodicity can be efficiently judged by determining the position of the defect candidate part which is a judgment object in the polarizing plate surface, and screening what exists at the said predetermined space|interval.

In one embodiment, determination of the presence or absence of periodicity of a defect candidate part is performed based on the positional coordinate (for example, the positional coordinate in a long direction) of a defect candidate part. For example, the positional coordinates of the defect candidate units transmitted from the defect candidate unit extraction unit (for example, two or more, preferably three or more adjacent defect candidate units in the long picture direction) are calculated (theoretically) as a non-part by design. When the position coordinates coincide with the position coordinates of the miner, it can be determined that the defect candidate part has periodicity. In addition, for example, based on the positional coordinates in the long direction of the defect candidate part transmitted from the defect candidate part extraction part, the defect candidate part to be judged and the non-polarization part existing on the upstream side in the conveyance direction (defect determined not to be a defect) It may be a candidate part), and it is performed based on whether the distance is a predetermined distance or not. The distance may be, for example, an arrangement interval of the non-polarization part in the long direction (that is, a predetermined interval in the long picture direction) or a distance obtained by multiplying the predetermined interval by an integer.

A-7. Process of detecting defects (5)

The defect detection part 88 detects a defect based on the size of a defect candidate part, or the size of a defect candidate part, and the presence or absence of periodicity. Specifically, the defect detection part 88 detects the defect candidate part judged by the size judgment part 84 as having a size equal to or less than a reference value as a defect. The defect detection unit 88 can also recognize the defect candidate portion judged to have periodicity in the periodicity determination unit 86 as a non-polarization portion, distinguish it from the defect candidate portion, and detect the remaining defect candidate portions as defects. In other words, the defect detection part 88 can detect the defect candidate part judged to have a size below a reference value, and the defect candidate part judged not to have periodicity as a defect.

It is a flowchart explaining the specific procedure of defect detection in one Embodiment of this invention. In embodiment shown in FIG. 4, image data of a polarizing plate is acquired first (the said process (1)). Next, a defect candidate part is extracted based on the image data (the said process (2)). Next, it is determined whether or not the candidate defect portion has a size equal to or less than the reference value (step (3) above), and the defect candidate portion having a size exceeding the reference value is determined as a non-polarization portion, while the defect candidate portion having a size less than or equal to the reference value is determined. Detect as a defect (step (5) above).

It is a flowchart explaining the specific procedure of defect detection in another embodiment of this invention. In embodiment shown in FIG. 5, image data of a polarizing plate is acquired first (the said process (1)). Next, a defect candidate part is extracted based on the image data (the said process (2)). Next, it is judged whether or not the defect candidate portion has a size equal to or less than the reference value (step (3) above), and the presence or absence of periodicity is determined for the defect candidate portion having a size exceeding the reference value (step (4) above) . Based on the obtained result, a defect candidate portion having a size equal to or less than the reference value and a defect candidate portion having a size exceeding the reference value but not having periodicity are detected as defects (step (5) above). In addition, the white circle in Fig.6 (a) shows all the defect candidate parts extracted in the process (2) by the said embodiment, and the white circle in Fig.6(b) has a size exceeding a reference value, and periodicity Defect candidate portions to be judged of presence or absence are indicated, black circles in Fig. 6(c) indicate defect candidate portions judged to have periodicity (non-polarization portions), and white circles indicate defect candidate portions determined not to have periodicity (defects). ), and white circles in Fig. 6(d) indicate defects that are finally detected.

A-8. Marking Process (6)

The inspection apparatus 100 may further be equipped with a marking apparatus (not shown). The marking apparatus is connected to the image processing apparatus, and when an image processing apparatus (substantially a defect detection part) detects a defect, it transmits the positional information of the defect to a marking apparatus. A marking apparatus marks a defect part based on the positional information. The marked area can be easily excluded as a bad polarizer after cutting. As a marking, the marking using a marker pen and laser marking are mentioned.

[B. Manufacturing method of polarizing plate]

The manufacturing method of the elongate polarizing plate containing the polarizer which has a non-polarization part of this invention is forming a non-polarization part in a long polarizer, manufacturing a polarizing plate using the long polarizer which has the non-polarization part, and said It includes inspecting the appearance of the polarizing plate by the inspection method.

B-1. polarizer

A polarizer is comprised from the resin film containing a dichroic substance typically. As a dichroic substance, an iodine, an organic dye, etc. are mentioned, for example. These may be used individually or in combination of 2 or more types. Preferably iodine is used.

Any suitable resin may be used as the resin for forming the resin film. Preferably, a polyvinyl alcohol-type resin is used. As polyvinyl alcohol-type resin, polyvinyl alcohol and an ethylene-vinyl alcohol copolymer are mentioned, for example. Polyvinyl alcohol is obtained by saponifying polyvinyl acetate. The ethylene-vinyl alcohol copolymer is obtained by saponifying the ethylene-vinyl acetate copolymer.

A polarizer (except a non-polarization part), Preferably it shows absorption dichroism at any wavelength of wavelength 380nm - 780nm. The single transmittance of a polarizer (except a non-polarization part) becomes like this. Preferably it is 39 % or more, More preferably, it is 39.5 % or more, More preferably, it is 40 % or more, Especially preferably, it is 40.5 % or more. In addition, the theoretical upper limit of single transmittance is 50 %, and a practical upper limit is 46 %. In addition, the single transmittance|permeability is a Y value which measured with the 2 degree field of view (C light source) of JIS Z8701, and performed visibility correction|amendment, For example, it can measure using a microscopic spectroscopy system (LVmicro by Lambda Vision). The degree of polarization of the polarizer (excluding the non-polarization portion) is preferably 99.9% or more, more preferably 99.93% or more, still more preferably 99.95% or more.

The thickness of the polarizer can be set to any appropriate value. The thickness is preferably 30 µm or less, more preferably 25 µm or less, still more preferably 20 µm or less, particularly preferably 10 µm or less. On the other hand, thickness becomes like this. Preferably it is 0.5 micrometer or more, More preferably, it is 1 micrometer or more.

The absorption axis of the polarizer can be set in any suitable direction according to the purpose. The direction of the absorption axis may be, for example, a long direction or a width direction. The polarizer which has an absorption axis in a long direction has the advantage that it is excellent in manufacturing efficiency, for example. The polarizer which has an absorption axis in the width direction has the advantage that it can laminate|stack by roll-to-roll and the retardation film which has a slow axis in a long direction, for example. In one embodiment, the absorption axis is substantially parallel to the direction of a long picture or the width direction, and the width direction both ends of a polarizer are slit-processed parallel to the direction of a long picture. According to such a structure, it can cut on the basis of the short side of a polarizer, has a non-polarization part at a desired position, and can manufacture easily the some polarizer which has an absorption axis in an appropriate direction. In addition, the absorption axis of a polarizer can respond to the extending|stretching direction in the extending|stretching process mentioned later.

A polarizer is typically obtained by performing various processes, such as a swelling process, an extending|stretching process, the dyeing process by the said dichroic substance, a crosslinking process, a washing process, a drying process, to the said resin film. When performing various processes, the resin layer formed on the base material may be sufficient as a resin film. Formation of the said non-polarization part can be performed also in the middle of the manufacturing process of a polarizer.

B-2. Formation of non-polarization part

Preferably, a non-polarization part is a discoloration part. According to this configuration, compared to the case in which the through hole is formed mechanically (for example, by a method of mechanically extracting using a Thomson blade punch, a floater, a water jet, etc.), cracks, delamination (delamination), Quality problems such as sticking out of the adhesive material are avoided. A discoloration part is preferably formed by making a basic solution contact the desired position of a polarizer (resin film containing a dichroic substance). The non-polarization part formed by such a method can become a low concentration part with a lower content of a dichroic substance than another site|part (non-contact part). Since content of the dichroic substance itself is low in a low concentration part, compared with the case where the decolorization part is formed by decomposing|disassembling a dichroic substance with a laser beam etc., transparency of a non-polarization part is maintained favorably.

Content of the dichroic substance in the said low concentration part becomes like this. Preferably it is 1.0 weight% or less, More preferably, it is 0.5 weight% or less, More preferably, it is 0.2 weight% or less. The lower limit of content of a dichroic substance in a low concentration part is below a detection limit normally. The difference between content of the dichroic substance in the said other site|part and content of the dichroic substance in a low concentration part becomes like this. Preferably it is 0.5 weight% or more, More preferably, it is 1 weight% or more. When using an iodine as a dichroic substance, iodine content is calculated|required from the X-ray intensity measured by fluorescence X-ray analysis with the analytical curve previously prepared using the standard sample, for example.

Any suitable compound may be used as the basic compound contained in the basic solution. Examples of the basic compound include hydroxides of alkali metals such as sodium hydroxide, potassium hydroxide and lithium hydroxide, hydroxides of alkaline earth metals such as calcium hydroxide, inorganic alkali metal salts such as sodium carbonate, organic alkali metal salts such as sodium acetate, aqueous ammonia, etc. can be heard Among these, hydroxides of alkali metals and/or alkaline earth metals are preferably used, and sodium hydroxide, potassium hydroxide and lithium hydroxide are more preferably used. It is possible to efficiently ionize the dichroic material, and it is possible to form a discolored part more conveniently. These basic compounds may be used independently and may be used in combination of 2 or more type.

As a solvent of a basic solution, water and alcohol are used preferably. The concentration of the basic solution is, for example, 0.01 N to 5 N, preferably 0.05 N to 3 N, and more preferably 0.1 N to 2.5 N. The liquid temperature of the basic solution is, for example, 20°C to 50°C. The contact time of a basic solution can be set according to the thickness of a polarizer, and the kind and concentration of the basic compound contained in a basic solution. The contact time is, for example, 5 seconds to 30 minutes, and preferably 5 seconds to 5 minutes.

As a method of contacting the basic solution, any suitable method may be employed. For example, about a polarizer, the method of dripping, coating, and spraying a basic solution, and the method of immersing a polarizer in a basic solution are mentioned. At the time of contact of a basic solution, you may protect a polarizer with arbitrary suitable protective materials so that a basic solution may not contact other than a desired site|part. As such a protective material, a protective film and a surface protective film are used, for example. A protective film can be used as it is as a protective film of a polarizer. A surface protection film is temporarily used at the time of manufacture of a polarizer. Since a surface protection film is removed from a polarizer at arbitrary appropriate timings, it is typically bonded to a polarizer through an adhesive layer. As another specific example of a protective material, a photoresist etc. are mentioned. Moreover, the base material used in the manufacturing process of the said polarizer can also be used as a protective material.

Preferably, at the time of contact of a basic solution, the polarizer surface is coat|covered with the surface protection film so that the at least one part may be exposed. The polarizer having an arrangement pattern of a non-polarization part like the example of illustration bonds the surface protection film in which the small circular through-hole corresponding to the desired non-polarization part size was formed in the position corresponding to the said arrangement pattern on one side of a polarizer, and a polarizing film laminated body It is prepared by preparing and contacting it with a basic solution. In that case, it is preferable that the other side (the side on which the surface protection film (1st protective film) in which the through-hole was formed) is also not arrange|positioned of the polarizer is also protected. It is preferable that bonding of a protective film or a surface protection film is performed with a roll-to-roll. In this specification, a "roll-to-roll" means aligning and laminating|stacking a mutual elongate direction, conveying a roll-shaped film.

Examples of the material for forming the surface protection film include ester-based resins such as polyethylene terephthalate-based resins, cycloolefin-based resins such as norbornene-based resins, olefin-based resins such as polyethylene and polypropylene, polyamide-based resins, and polycarbonate-based resins Resin, these copolymer resins, etc. are mentioned. Preferably, it is an ester-type resin (especially polyethylene terephthalate-type resin). This is because the elastic modulus is sufficiently high and, for example, deformation of the through hole is less likely to occur even if tension is applied at the time of conveyance and/or bonding. The thickness of a surface protection film is typically 20 micrometers - 250 micrometers, Preferably they are 30 micrometers - 150 micrometers.

A 1st surface protection film has the through-hole arrange|positioned in a predetermined pattern. The position of the through hole corresponds to the position where the non-polarization part is formed. The shape of a through hole corresponds to the shape of a desired non-polarization part. The through hole is formed, for example, by mechanical punching (eg punching, Thomson blade punching, plotter, water jet) or removal of a portion of the film (eg laser ablation or chemical dissolution).

In one embodiment, the said basic solution is removed from a light polarizer by arbitrary appropriate means after contacting with a light polarizer. According to such embodiment, for example, the fall of the transmittance|permeability of the non-polarization part accompanying use of a polarizer can be prevented more reliably. As a specific example of the removal method of a basic solution, washing|cleaning, wiping removal by a wet etc., suction removal, natural drying, heat drying, ventilation drying, reduced pressure drying, etc. are mentioned. Preferably, the basic solution is washed. As a washing|cleaning liquid used for washing|cleaning, alcohol, such as water (pure water), methanol, and ethanol, and these mixed solvents, etc. are mentioned, for example. Preferably, water is used. The number of times of washing|cleaning is not specifically limited, You may carry out in multiple times. When removing a basic solution by drying, the drying temperature is 20 degreeC - 100 degreeC, for example.

Preferably, the alkali metal and/or alkaline-earth metal contained in the resin film are reduced in the contact part which made the basic solution contact after the contact with the said basic solution. By reducing an alkali metal and/or an alkaline-earth metal, the non-polarization part excellent in dimensional stability can be obtained. Specifically, even in a humidified environment, the shape of the non-polarization part formed by contact with a basic solution can be maintained as it is.

By contacting the basic solution, hydroxides of alkali metals and/or alkaline earth metals may remain in the contact portion. Moreover, by making a basic solution contact, the metal salt (for example, borate) of an alkali metal and/or alkaline-earth metal can be produced|generated in a contact part. These can generate hydroxide ions, and the generated hydroxide ions can act (decompose/reduce) on a dichroic substance (for example, an iodine complex) existing around the contact portion to widen the non-polarization region. Therefore, by reducing the alkali metal and/or alkaline earth metal salt, it is considered that the non-polarization region can be suppressed from spreading over time, and the desired non-polarization portion shape can be maintained.

It is preferable that content of the said non-polarization part is 3.6 weight% or less of an alkali metal and/or alkaline-earth metal, More preferably, it is 2.5 weight% or less, More preferably, it is 1.0 weight% or less, Especially preferably, it is 0.5 weight%. is below. Content of an alkali metal and/or alkaline-earth metal can be calculated|required with the analytical curve previously prepared using the standard sample from the X-ray intensity measured by fluorescence X-ray analysis, for example.

As a method for the said reduction, Preferably, the method of making an acidic solution contact the contact part with a basic solution is used. According to such a method, an alkali metal and/or alkaline-earth metal can be efficiently transferred to an acidic solution, and the content can be reduced. Contact with an acidic solution may be performed after removal of the said basic solution, and may be performed without removing a basic solution.

Any suitable acidic compound can be used as the acidic compound contained in the acidic solution. Examples of the acidic compound include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid and hydrogen fluoride, and organic acids such as formic acid, oxalic acid, citric acid, acetic acid and benzoic acid. Among these, the acidic compound contained in the acidic solution is preferably an inorganic acid, and more preferably hydrochloric acid, sulfuric acid or nitric acid. These acidic compounds may be used independently and may be used in combination of 2 or more type.

As a solvent of an acidic solution, water and alcohol are used preferably. The concentration of the acidic solution is, for example, 0.01 N to 5 N, preferably 0.05 N to 3 N, and more preferably 0.1 N to 2.5 N. The liquid temperature of the acidic solution is, for example, 20°C to 50°C. The contact time of an acidic solution is 5 second - 5 minutes, for example. In addition, as the method of contacting the acidic solution, the same method as the method of contacting the basic solution may be employed. In addition, the acidic solution can be removed from the polarizer. As the method for removing the acidic solution, the same method as the method for removing the basic solution may be employed.

Typically, after the non-polarization portion is formed as described above (preferably after reduction of alkali metal and/or alkaline earth metal), the surface protection film can be peeled off.

B-3. manufacture of polarizer

The elongate polarizer which has a non-polarization part obtained by making it above typically comprises the laminated body of a polarizer/protective film. While the laminate can be used as it is as a polarizing plate, a polarizing plate having any suitable configuration as a final product can be obtained by laminating other structural members such as a protective film on the laminate according to the purpose or the like. Similarly, when a polarizer composed of a single resin film is obtained, a polarizing plate having any appropriate configuration as a final product can be obtained by laminating other structural members such as a protective film on one or both sides thereof depending on the use or the like. About the other structural members to be laminated|stacked, it is as described in Section A-1.

The lamination|stacking of the said other structural member can be performed by what is called a roll-to-roll.

B-4. Visual inspection of polarizer

The polarizing plate obtained by making it above is used for the test|inspection method of A term. By inspecting the external appearance of the polarizing plate having the non-polarization part by the inspection method according to the item A, the target defect (foreign substance, bubble, pinhole, etc.) can be detected without erroneously detecting the non-polarization part as a defect, so inspection efficiency It becomes possible to achieve high degree of compatibility with inspection precision. As a result, a high-quality polarizing plate can be obtained with excellent manufacturing efficiency.

B-5. Cutting of the polarizer

The manufacturing method of the polarizing plate of this invention may further include the process of cutting a long polarizing plate to a desired size. Cutting may be performed by cutting, punching, or the like. The elongate polarizing plate is preferably cut so as to have a non-polarizing part at a position corresponding to the camera part while having a size corresponding to the mounted image display device and mounted on the image display device.

Since the polarizing plate to be cut is preferably marked on the defective portion, the polarizing plate, which is a defective product, can be easily excluded based on the marking after cutting.

When manufacturing the polarizing plate provided in camera-equipped image display apparatuses (liquid crystal display apparatus, organic electroluminescent device), such as mobile phones, such as a smart phone, notebook PCs, tablet PCs, for example, the inspection method of this invention is preferable, for example used

10: polarizer
10a: non-polarization part
30: polarizer
50: imaging device
80: image analysis device
82: defect candidate part extraction unit
84: size determination unit
86: periodicity judgment unit
88: defect detection unit
100: inspection device

Claims (10)

Forming a non-polarizing part arranged at a predetermined interval in a long polarizer in a long picture direction, manufacturing a long polarizing plate using a long polarizer having the non-polarizing part, and conveying the long polarizing plate in a long picture direction As a manufacturing method of a polarizing plate comprising inspecting the appearance while
Inspecting the appearance of the long polarizing plate,
A process of acquiring image data by imaging the polarizing plate;
analyzing the image data to extract a defect candidate part;
a step of determining whether the defect candidate portion has a size equal to or less than a reference value;
a step of judging whether or not the defect candidate portion has periodicity in the elongate direction only for the defect candidate portion having a size exceeding the reference value;
a process for detecting defects;
The process of detecting the defect has a defect candidate part which has a size below a reference value, and a size exceeding a reference value, and includes detecting as a defect the defect candidate part which does not have periodicity. The method of claim 1,
The manufacturing method of the polarizing plate which forms the non-polarization part arrange|positioned at predetermined intervals in the elongate direction and the width direction in the said elongate polarizer. 3. The method of claim 1 or 2,
The manufacturing method of the polarizing plate in which acquisition of the said image data is performed based on continuous imaging of the said polarizing plate. 3. The method of claim 1 or 2,
The manufacturing method of the polarizing plate in which extraction of the said defect candidate part is performed based on the luminance information of the said image data. 3. The method of claim 1 or 2,
The manufacturing method of the polarizing plate in which judgment of the periodicity of the said defect candidate part is performed based on the positional coordinate in the long direction of the said defect candidate part. 3. The method of claim 1 or 2,
The distance in the long direction of the defect candidate part to which the judgment of the periodicity of the defect candidate part is determined and the non-polarization part existing upstream in the conveyance direction is an integer multiple of the arrangement interval of the non-polarization part in the long direction or the interval The manufacturing method of a polarizing plate which is performed based on whether it is one distance. 3. The method of claim 1 or 2,
After inspecting the appearance, the method for producing a polarizing plate, further comprising cutting the long polarizing plate to a desired size. 3. The method of claim 1 or 2,
The manufacturing method of a polarizing plate which forms the said non-polarization part in the said elongate light polarizer by contact with a basic solution. delete delete

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