CZ2010740A3 - Method of inspecting polarizing film - Google Patents

Abstract

Defects in the polarizing film are detected using a defect detection device (S2). Based on the result of the defect detection, the data describing the defect position is created and stored in the storage medium (S3). The strip-like polarizing film is wound into a coil (S5). The strip-like polarizing film is then unwound from the roll (S6) and another film (S7) is laminated thereon. After the next film is non-laminated, the defect position data stored in the memory medium and, based on the read data, the defect position of the polarizing film (S8) is specified, and the next film creates a mark adjacent the defect according to the specified defect position (S9). This makes it possible to create markers adjacent to defects detected by the defect inspection device without becoming a useless part of the polarizing film that contains only tolerable defects.

Description

Method of controlling polarizing film

Field of the Invention

The present invention relates to a method of inspecting a polarizing film, comprising detecting a defect in the strip-like polarizing film, then winding the polarizing film into a roll, unwinding the polarizing film from the lamp, laminating other films to the polarizing film, and forming a mark adjacent to the defect.

Background Art [0002]

In the process of producing a polarizing film used for liquid crystal displays and the like, it is customary for various processes to be automatically performed on a polarizing film having the shape of a long strip of constant width. The polarizing film is optionally cut into prescribed shapes in accordance with the product specification.

[0003]

A conventional known method for inspecting a polarizing film is to perform a defect inspection device (automatic inspection machine) automatically detecting defects in the polarizing film in the form of a strip, and to create marks adjacent to the defects to easily detect defects in the subsequent process (e.g. JP 2001-305070 A, published October 31, 2001).

[0004]

Generally speaking, a polarizing film in which defects are detected by a defect detection device is not entirely unusable. Defects detected by the device /[11.2308-1 Q = No Faults can be tolerable if the defects are small in size. The defect inspection device is normally not able to determine if the defects are greater than the tolerable size. As such, the defect inspection device detects all defects, whether or not they are tolerable in size. Whether the defects detected by the defect inspection device are tolerable or not are, as the case may be, usually determined by visual inspection by human eye.

[0005]

The marks formed on the polarizing film are generally non-erasable. In particular, the marks formed by the marker cannot be wiped off the polarizing film.

[0006]

In a conventional inspection method, when the defect inspection device detects a defect in the polarizing film, marks are simply formed adjacent to the defects directly on the polarizing film. For the above reason, marks thus created cannot be erased after visual inspection has determined that the defects are tolerable. This raises the problem that a portion of the polarizing film which contains, as all detected defects, only at least one tolerable defect cannot be used as a product due to the mark formed on the polarizing film, although this portion is suitable for use as a product.

SUMMARY OF THE INVENTION

The present invention is directed to the above problem, and an object of the present invention is to provide a method of inspecting a polarizing film that makes it possible to create a mark adjacent to a defect detected by the defect inspection device without causing the part of the polarizing film to check for defects only

The at least one tolerable defect is the product.

To achieve the above object, not usable as a method of inspecting a polarizing film according to the present invention comprises the steps of: (a) detecting a defect inspection by means of a polarizing film defect device in the form of a strip; (b) recording the defect position by creating, based on the defect detection result, defect position data indicating the defect position, and storing the defect position data in a storage medium; (c) winding the polarizing film in the form of a strip into the roll after detecting the defect; (d) unwinding the polarizing film in the form of a strip from laminating another film to a polarizing film in the form of a strip unwound from a roll; and (f) forming the mark by (i) reading the defect position data stored in the storage medium after the next film is laminated, (ii) defining the polarizing film defect position based on the read defect position data, and (iii) creating the mark on the next film adjacent to the defect according to the specified defect position. Further, to achieve the above object, the method of inspecting a polarizing film according to the present invention comprises the steps of: (a) detecting a defect of the polarizing film in the form of a belt using a defect inspection device; (b) printing, based on the outcome of the defect, an identification code indicating the position of the defect of the polarizing film on the end portion in the transverse direction, and winding the polarizing film in the form of a strip on which the identification code is printed; (c) unwinding the polarizing film in the form of a strip from the roll; (d) laminating the additional film to a polarizing film in the form of a strip unwound from a roll; and (e) forming a mark by (i) reading the identification code printed on the polarizing film after the next film is laminated, (ii) defect position specification

And (iii) forming a mark on the next film adjacent to the defect according to the specified defect position.

[0009]

In the conventional inspection method, the step of detecting the polarizing film defect by the defect inspection device and the step of forming the mark adjacent the defect is performed simultaneously. In contrast, in the inspection method of the present invention, the step of detecting a polarizing film defect by means of the defect inspection device and the step of forming a mark adjacent to the defect are separated from each other, and a laminating step is performed between the two steps. This produces the effects described below.

[0010]

Typically, a polarizing film is laminated to other films such as a release film and the like. The release film is usually removed when the polarizing film is used for a liquid-crystal screen and the like. Marks created on other movies, such as release film, are erasable. In particular, the marks formed by the marker can generally be wiped off from other films, such as a release film and the like.

[0011]

Accordingly, in the inspection method of the present invention, no mark is simultaneously generated during the defect inspection by the defect inspection device. After another film, such as a release film or the like, is laminated to the polarizing film (e.g.

film such as release film or alike attached glue on polarization film], Yippee mark created in the neighborhood defects of the next film (jhoho upper layer). It allows Delete a tag when Yippee visual control z sure, that the defect is connected with tag has tolerable size. Part of polarization film which contains as

01-2308-10-Any defects detected by the inspection device with only at least one tolerable defect can be used as a product when the marks are deleted.

[0012]

Consequently, the present invention may provide a method of inspecting a polarizing film that makes it possible to create a mark adjacent to a defect detected by the defect inspection device without causing the portion of the polarizing film to contain at least one tolerable defect detected by the defect inspection device. defect is unusable.

[0013]

The conventional inspection method also contemplates simultaneous execution after all other films are laminated to the polarizing film, the step of detecting the polarizing film defect by the defect inspection device and the step of forming a mark adjacent the defect. In this method, it is not possible to distinguish whether a defect detected by the defect inspection device exists on the polarizing film or on one of the other films laminated on the polarizing film. In contrast, in the inspection method of the present invention, a defect in the polarizing film can be detected with certainty because the defect inspection device detects the defect before the next film is laminated.

[0014]

In the conventional method described in JP 2001-305070 A, a mark is formed adjacent to a defect upon detection of the defect during the inspection of the polarizing film defects.

[0015]

In contrast, according to the method of the present invention, the step of winding the polarizing film in the form of a strip into the coil and the step of unwinding the polarizing film from the coil between the step of performing a defect inspection on the polarizing film in the form of a coil

01-2308-10-Eng

-6 a strip and a step of laminating another film to a polarizing film in the form of a strip. This is because the steps of producing the polarizing film and performing defect inspection on the polarizing film in the form of a strip are carried out at a factory other than the factory where the step of laminating another film to the polarizing film in the form of a strip is performed. This means that it is necessary to transport the polarizing film in the form of a strip from one factory to another. In addition, a polarizing film in the form of a generally long strip is difficult to transport if it is not wound into a roll.

[0016]

In the conventional inspection method, defect inspection and tagging are performed simultaneously. It is not necessary in itself to record the defect information, and it is sufficient to transmit the signal from the defect inspection device to the marking device. In the inspection method according to the present invention, as described above, the defect inspection steps and the mark creation step are separated from each other. In addition, between the defect inspection step and the mark forming step, a step of winding the polarizing film into the roll and the step of unwinding the polarizing film from the roll is performed. Thus, the result of the inspection needs to be somehow recorded during the defect inspection so that the recording can be used later in the mark creation step. [0017]

Therefore, in the inspection method of the present invention, based on the defect detection result, the defect position data is generated indicating the defect position and stored in the storage medium in the defect position recording step. In the tagging step, after the next film is laminated, the defect position data stored in the storage medium is read, and the defect position of the polarizing film is specified based on the read defect position data. In accordance with the specified defect position, a mark is formed on the next film so that it is

01-2308-10-Eng

-Ί created in the vicinity of defects. This allows the mark to be formed adjacent to the defect even if the defect inspection step and the mark creation step are separated from each other and the step of winding the polarizing film into the roll and the step of unwinding the polarizing film from the roll is performed between the defect inspection step and the marking step.

[0018]

In the inspection method of the present invention, the step of recording the position of the defects (b) comprises: printing an identification code on the polarizing film on the end portion of the polarizing film in the transverse direction, based on the defect detection result; the entire polarizing film in the form of a strip segmented according to dividing lines parallel to the transverse direction of the polarizing film; generating the defect position data as defect position data in the defect-containing area; and storing the defect position data in a storage medium associated with the defect-containing area, and the step of creating marks (f) comprising: reading an identification code on the polarizing film; and specifying the defect position of the polarizing film based on the defect position data associated with the area identified by the read identification code. [0019]

According to the present invention, the specification of the position of the polarizing film defect is considered based only on the defect position data indicating the position of the defect by position coordinates relative to the position of the front of the polarizing film in the longitudinal direction. However, the polarizing film may extend in the longitudinal direction after inspection of the defects and before forming the mark. The actual specification of the position of the polarizing film defect based on only the defect position data indicating the position of the defect by position coordinates relative to the position of the front of the polarizing film in its longitudinal

01-2308-10-Eng

-8 ♦ · «*

The position of this connection, the polarizing film defects described above, the method specifies, based on both the identification code (bar code) and the position data of the defect defect. Thus, in comparison to the polarization with the case where the defect position data of the film is specified only, the defect position can be accurately specified.

Further, according to the method described above, the position of the polarizing film defect is specified on the basis of a greater amount of information than when the position of the polarizing film defect is specified only on the basis of the identification code. Thus, the position of the polarizing film defect can be identified more precisely and the mark can be formed with higher accuracy.

[0021]

The inspection method of the present invention, wherein the identification code is printed, preferably further comprises the step of performing a corona discharge treatment of the polarizing film in the transverse portion before the identification code is printed.

The polarizing film is generally difficult to accept printing ink and is therefore relatively poorly printable. According to the method described above, the corona treatment (treatment by applying a root charge to a polarizing film) is carried out on the polarizing film at the end portion of its surface in the transverse direction. This treatment roughens the end portion of the surface of the polarizing film in the transverse direction, making the polarizing film more adhesive for easier acceptance of the printing ink (for the printing ink), thus avoiding wiping the printed identification code (removal)

-2308-10-Eng printing ink). This method described above is certainly applicable also to a polarizing film having low adhesion.

[0023]

Further, in the inspection method of the present invention, in the step of forming the mark (f), the mark is preferably formed using a plurality of markers arranged along the transverse direction of the polarizing film.

[0024]

The marking may be performed, for example, by moving one marker in the transverse direction of the polarizing film such that the marking is performed by only one marker. However, this may fail to create tags in the vicinity of some defects if a large number of defects occur simultaneously.

[0025]

On the other hand, according to the method described above, the marking is performed using a plurality of markers arranged along the transverse direction of the polarizing film. This allows marking in the neighborhood of all defects even when a large number of defects occur simultaneously. As a result, it is possible to prevent the polarizing film containing the defects from being wrongly classified as a perfect product.

[0026]

Other objects, features and advantages of the present invention will become apparent from the following description. The benefits of the present invention will be apparent from the following explanation with reference to the accompanying drawings.

Brief Description of the Drawings [0027]

Giant. 1 is a flowchart showing an overview of a method of inspecting a polarizing film according to an embodiment of the present invention.

01-2308-10-Eng

- 10Fig. 2 is a block diagram illustrating a diagram of a polarizing film production line used for defect inspection and the like in a polarizing film defect inspection method according to an embodiment of the present invention.

Giant. 3 is a drawing showing how polarizing films are sorted after the initial polarizing film strip is cut.

Giant. 4 is a block diagram schematically illustrating an automatic inspection apparatus used in a polarizing film inspection method according to an embodiment of the present invention.

Giant. 5 is a diagram schematically illustrating the coding of image data of a starting strip of polarizing film in the above-mentioned automatic inspection apparatus.

Giant. 6 is a block diagram schematically illustrating a marking apparatus used in a method of inspecting a polarizing film according to an embodiment of the present invention.

Giant. Ί is a diagram schematically illustrating how the position for creating a mark based on the bar code and the defect position data is determined in the above-mentioned automatic monitoring device.

Giant. 8 is another block diagram illustrating a diagram of a marking device used in a method of inspecting a polarizing film according to an embodiment of the present invention.

Exemplary Embodiment

An embodiment of the method of controlling a polarizing film according to the present invention is schematically described with reference to Fig. 1.

[0029]

01-2308-10-Eng

First, the initial strip of the polarizing film (a long strip polarizing film from which a plurality of polarizing films of different sizes can be cut by corona discharge at the end portion of the initial strip in the transverse direction (S1) is treated. Step Ξ1 is designed to roughen the end portion of the surface of the polarizing film in the transverse direction to increase the adhesion of the initial strip of the polarizing film for the printing ink to prevent the identification code printed on it. high adhesion, step S1 can for example be omitted.

[0030]

Then, the defect inspection device checks for defects (cracks, foreign material contamination, bubbles, and the like) present on and / or within the initial polarizing film web. The presence of defects is checked on the basis of each of the many areas on which the entire polarizing film in the form of a strip is segmented according to dividing lines parallel to the transverse direction of the polarizing film. The inspection thus determines the position of the defects in the area containing the defect (S2).

[0031]

The controlled polarizing film may be a monolayer polarizing film or a monolayer polarizing film laminated with one or more layers. These, one or more layers, may be a protective film; an optical film such as a reflective film, a semipermeable film, a retardation film, a viewing angle compensating film, or a brightness enhancing film; etc. As a single-layer polarizing film, a film of, for example, polyvinyl alcohol dyed with a dichroic dye material (eg, iodine, a dichroic dye, etc.) may be used. The thickness of the single-layer polarizing film is without

01-2308-10-Eng

It would be particularly limited, for example, about 1 pm to 150 pm. With respect to ease of stretching and the like, the film thickness is preferably 10 µm or more. The controlled polarizing film is preferably formed from a single-layer polarizing film and protective films laminated to both surfaces of the single-layer polarizing film. In the case where the monolayer polarizing film is laminated with a protective film, it is preferred that the present invention is not so limited if the protective film is laminated to the monolayer polarizing film with an adhesive such as an adhesive made of vinyl alcohol resin . Examples of the protective film include acetylcellulose resin (such as triacetylcellulose (TAC)), norbornene resin, polycarbonate resin, acrylic resin and the like.

In terms of polarizing properties, shelf life, etc., triacetylcellulose is particularly preferred. Typically, the protective film used has a thickness of 100 µm or less, preferably 60 µm or less, more preferably 50 µm or less. Optionally, a surface treatment such as a gloss treatment, a hardened coating treatment, an antireflective treatment and an antistatic treatment can be applied to the surface (outer surface) of the protective film on the opposite side to the adhesive surface of the protective film. Since the acetylcellulose resin does not necessarily have sufficient adhesion for the polyvinyl alcohol resin, it is preferred that a saponification process is performed on the bonded surface.

[0032]

Based on the defect detection result in step S2, the defect position data is coded to produce a defect position data that indicates the defect position in the defect-containing area. The defect position data is stored in a storage medium associated with the defect containing area (S3). In this step, there is a region

01-2308-10-Eng

13 comprising a defect, for example, divided into a plurality of sections arranged in a grid pattern. The image data of the defect-containing area is captured by the image capturing device and converted to binary data representing information about each section in a binary manner (the defect-containing section information is represented in black, and the defect-free section information is represented in white). The binary data is further converted to a defect position data consisting of binary code strings in which the defect-containing section (black section) is represented by "1" and the defect-free section (white section) is represented by "0". The defect position data is stored in the storage medium.

[0033]

Of the plurality of regions on the polarizing film in the form of a strip, which regions are segmented according to dividing lines parallel to the transverse direction of the polarizing film, a (one-dimensional) barcode is printed based on the defect inspection result in step S2 so that the barcode is printed in an end portion of the region in the transverse direction of the polarizing film (S4). The bar code must be identified with the defect-containing areas, and each defect-containing area is provided with a barcode and uniquely identified with it. Barcodes are printed in the areas containing the defects, which serve as identification codes for area identification (S4). For example, the bar code indicates the sequence number of the area associated with the bar code in the order of the areas containing the defects detected in the polarizing film.

The barcode is printed on the front end portion of the area (defect area) containing the defect.

Barcodes are printed by a printer, such as an inkjet printer.

[0034]

01-2308-10-Nr

The position in which the barcode is printed in step S4 is located in the part of the polarizing film that is ultimately not used as a product. For example, the bar code printing position is located in the knurled portion having a prescribed width (e.g. 10 mm) and located on the polarizing film in the end portion in the transverse direction. The bar code is printed on the polarizing film so that it has a width of 7 mm in the transverse direction in the end portion. Corona discharge treatment at Ξ1 should be performed at least on the part where the bar code is to be printed, i.e. the knurled part of the polarizing film. It is preferred that the corona discharge treatment is performed on a region outside the effective region of the polarizing film that is used as the product.

[0035]

Upon detection of the defect in step S2, the polarizing film in the form of a strip is wound into a roll (S5). The polarizing film in the form of a strip is then stored and transported in the form of a roll.

[0036]

Then, the polarizing film in the form of a strip is unwound from a roll (S6). One, two, or more layers of other films (S7) are laminated onto a polarizing film in the form of a strip unwound from a roll.

[0037]

Examples of other films include a release film (separator); an optical film such as a reflective film, a semipermeable film, a retardation film, a viewing angle compensating film, and a brightness enhancing film; protective film and the like. The release film is intended to protect the adhesive layer disposed on the surface of the polarizing film against contamination until use. The adhesive layer is arranged to attach the polarizing film to another element such as a liquid-crystal cell. The release film may be any film having such suitable adhesion that it can

01-2308-10-Eng

the release film can be easily removed before using the polarizing film. In particular, as a release film, for example, a film made of polyethylene resin and a film made of polyester resin are generally used. To suitably adjust the adhesion and releasability of the release film, a surface treatment, such as plasma and corona treatment, ultraviolet treatment, and frame treatment, may be performed on the release film surface to be adhered to the polarizing film. Alternatively, an adhesive layer, a silicone-type or fluorine-type release agent layer, a surface-active layer, or the like may be provided on the same surface. Preferably, the release film thickness is, for example, 30 µπι or more.

[0038]

After further films are laminated in step S7, in step (S8) the bar code printed on the polarizing film at the end portion in the transverse direction is read. In the case where the bar code contains the sequence number of the area associated with the bar code in the order of the areas containing the defects detected in the polarizing film, the sequence number is read.

[0039]

In addition, the defect position data stored in the storage medium (S8) is read. In the manufacturing method of Fig. 1, steps S1 to 55 are typically performed at a factory producing the polarizing film, while steps S6 to 510 are performed at a processing factory other than the factory producing the polarizing film as shown in Fig. 1. it is necessary that the data stored in the storage medium at the polarizing film factory be transferred from the storage medium at the polarizing film factory to the processing factory in advance of using the defect position data at 38. The data can be converted, for example, as follows: (1) defect location data is

01-2308-10-Eng

6 stored in removable storage media such as USB (Universal Serial Bus) and CD-R (CD Recordable). The removable storage medium is then separated from the defect position data generating device and forwarded to the processing plant. At the processing factory, the defect position data is read from a removable storage medium, (2) The defect position data is stored in a storage medium such as a hard disk, and the defect position data is transferred from the storage medium to the processing factory via a communication network such as LAN Area Network).

[0040]

Further, the data read from the bar code is verified using the position information data for specifying (calculating) the defect position of the polarizing film based on the defect position data associated with the area identified by the bar code (S8). The calculation can be performed in an inverse manner to the coding in step Ξ3. That is, in this step, the sequence number of the area containing the defect based on the bar code can be verified using the defect position data read from the storage medium. The position of the polarizing film defect can be calculated by the conversion process inverse to the encoding in step S3.

[0041]

Then, based on the position of the defect specified in step S8, a mark adjacent to the specified defect (S9) is formed on the next film. In this case, it is advantageous if the mark consists of two

linear marks with a defect between them. It not only allows that was a defect easily recognizable, but also ensure that that there is no fault outside area clamped between two lines signs. [0042] Finally, polarizing film in belt form, on which is

a mark is wound into a roll (S10).

0b230840-č

-17

The polarizing film thus wound into the coil is then cut into a plurality of polarizing films having sizes depending on the application. Polarizing films are categorized into flawless products and defective products, for example based on whether or not they are labeled, and flawless products are classified as end products. Polarizing films as end products can be used, for example, for liquid crystal displays, organic EL displays, plasma displays and the like. Note that step S10 can be omitted, and cutting and sorting can be performed directly after step S9.

[0044]

In step S7, another film (s) may be laminated to one or both surfaces of the polarizing film. If the other film (s) is laminated on one side of the polarizing film, a marking may be made on the side of the polarizing film on which the other film (s) are laminated to the surface in step S8. In the event that the other film or films are laminated on both sides of the polarizing film, the mark may be formed on either side of the polarizing film after the other films are laminated. [0045]

Steps S2 to S5 in Fig. 1 can be performed using, for example, the polarizing film production line shown in Fig. 2.

[0046]

In the polarizing film production line, the initial polarizing film strip 1 is conveyed by means of transport rollers (not shown) or the like. As shown in Fig. 2, the protective film 3 formed from TAC or the like is laminated on both surfaces of the initial polarizing film web 1 for

01-2308-10 forming a starting strip 4 of a polarizing film. The starting strip 4 of the polarizing film is then wound into a roll 13.

[0047]

In the above polarizing film production line, there is an automatic in-line inspection device for automatically checking for defects in the polarizing film starting strips 1 and 4, which consists of an image capturing device 2 and an image processing device (not shown). The initial polarizing film strip 1 is used, for example, as a polarizing plate in a liquid-crystal display. Liquid crystal displays and the like achieve high resolution. Desirably, there is no minor defect in the polarizing film on the initial strip of the polarizing film that is visually barely discernible as it would impair the quality of the high-resolution screen display. In some cases, it may be difficult to visually detect even a defect covering a relatively large area, konfiguraci the above-described configuration performs various imaging processes of the appearance of the initial polarizing film strip 1, which is imaged by the image capturing devices 2 and 7. This makes it possible to detect as defects that are visually barely discernible.

[0048]

In the image capturing device 2, the light source 2b illuminates the starting band. of the polarizing film from the back surface of the polarizing film starting strip 1 so that the camera 2a positioned above the front surface of the polarizing film starting strip 1 can capture the image of the polarizing film starting strip 1 in normal light transmission and can transmit image data to an image processing device (not shown) . The image processing apparatus (not shown) detects a defect of the initial polarizing film strip 1 based on the image data supplied by the camera 2a. It allows

01-2308-] O-Ce

detect foreign material and flaws on the polarizing film as defects. In addition, it is possible with high sensitivity to detect a defect of the polarizing film starting strip 1 by a combination of methods such as: a method of illuminating the polarizing film starting strip 1 from above using a light source above the polarizing film starting strip 1; above the starting band ý of the polarizing film; a method of illuminating the starting polarizing film strip 1 from below by a light source below the starting polarizing film strip 1 and capturing the reflected polarizing film strip 1 in a reflected light by a camera located below the polarizing film starting strip 1; and a method of illuminating the starting polarizing film web 1 from below by a light source below the starting polarizing film web 1 and capturing an image of the starting polarizing film web 1 by a camera positioned above the polarizing film starting web 1 via a polarizing plate arranged in crossed nickels with the polarizing film starting web 1.

[0049]

In the image capturing device 7, the light source 7b illuminates the polarizing film starting strip 4 from the back of the surface of the polarizing film starting strip 4 so that a camera 7a located above the front surface of the polarizing film starting strip 1 can capture light and may transmit image data to an image processing device (not shown). The image processing apparatus (not shown) detects a defect of the initial polarizing film strip 1 based on the image data supplied by the camera 7a. By means of these devices, foam bubbles and foreign materials (germs) existing between the polarizing film starting band 1 and the protective films 3 as

01-2308-10-Eng

In addition, it is possible with high sensitivity to detect a defect of the initial polarizing film strip 4 by a combination of methods such as: a method of illuminating the polarizing film 4 from above by means of a light source above the polarizing film initial strip 4 and a polarizing film in reflected light by a camera positioned above the starting band 4 of the polarizing film; a method for illuminating the starting polarizing film strip 4 from below by a light source below the starting polarizing film strip 4 and capturing the reflected polarizing film strip 4 in the reflected light by a camera located below the polarizing film starting strip 4; and a method of illuminating the starting polarizing film web 4 from below by a light source below the starting polarizing film web 4 and acquiring an image of the starting polarizing film web 4 by a camera positioned above the starting polarizing film web 4 via a polarizing plate arranged in crossed nickels with the starting polarizing film web.

[0050]

The cameras 2a and 7a are preferably CCD cameras, although they may be other types of cameras.

[0051]

Preferably, the light sources 2b and 7b are capable of uniformly illuminating the starting strip 11 of the polarizing film over the entire width. Tubular radiators such as fluorescent lamps of a light source such as tubular lamps can be used as light sources 2b and 7b.

and linear

The tubular luminaire consists of a rod-shaped light guide and an intense light source such as a halogen lamp located on the surface of the end portion in the axial direction of the rod-shaped light guide. The light incident on both surfaces of the end portion of the rod-shaped light guide is guided by the side surfaces between the two surfaces of the end portions of the rod-shaped

01-2308-10-Eng

• * 4 4 4 • ·· ·· «· β · · « ·· · • · · • • • · • • · · ♦ • 4 · • · • * · • • * « • «« « ··· 44 · ··· • 4

the light guide so that the light guide and the intense light source can function as a rod-shaped light source. Alternatively, light sources 2b and 7b may be formed by diffuse illumination with laser beams. The light emitted to the initial polarizing film bands 1 and 4 from the light sources 2b and 7b is adjusted to certain wavelengths and polarizing characteristics so that the defects can be easily detected.

[0052]

Thus, the automatic inspection device shown in FIG. 2 performs a defect inspection using a plurality of image capture devices 2 and 7 arranged along the transport direction of the initial polarizing film web. Defect checks are performed before and after the lamination step of the protective film 3 using image capturing devices 2 and 7 which capture images of the initial polarizing film web in normal light transmittance. If a defect is detected using any type of image capturing device 7 and the image capturing device 7, the image processing device (not shown) determines that the initial polarizing film strip (1 or 6) contains a defect.

[0053]

According to the above configuration, defects of various kinds can be detected by using the most suitable optical system (image capture device 2 or 7) for defect detection. Thus, the sensitivity for detecting a number of types of defects can be improved. In addition, the above-described configuration performs an inspection on the upper side of the production line shown in FIG. As a result, the number of erroneous detection (error checking) defects can be reduced.

[0054]

01-2308-10-Eng

- 23 • · «

Μ V • · •>

* * ·

The structure of the automatic inspection device is not limited to the structure shown in FIG. 2. The automatic inspection device may be configured to use only part of the image capture devices 2 and 7. In terms of production efficiency, it is preferred that the automatic inspection device performs on-line inspection as shown in Figure 2. However, the inspection may also be performed off-line.

[0055]

A barcode 17 representing defect information (defective spots, defective coordinates, defective content and the like) is printed on the starting strip 4 of the polarizing film. The starting band 6 of the polarizing film is then wound into a roll 13.

[0056]

An example of steps S1 to S5 in Fig. 1 is now described with reference to Figs. 4 and 5.

[0057]

As shown in Fig. 4, the automatic inspection device that performs steps S1 to S5 in Fig. 1 includes an image capture device for detecting defects in the initial polarizing film web 1, an image viewing device 14, a barcode control, and a printer barcode.

Although in FIG.

2, the conveyor rollers of the conveyor path of the initial strip 1 of the polarizing film towards the roller 13 shown in FIG. 2 are arranged in the automatic monitoring device. of a polarizing film into a roll.

The image capturing device 2 takes pictures of the entire polarizing film starting band L and passes the image data to the image processing device 14.

[0058]

01-2308-10-Eng

♦ 44 4 4 4 44 and· « * 44 • 4 44 · * • • B • 4 • 4 4 • • 4 4 4 • 4 4 4 4 • and 4 4 4 • 4 4 «4» 44 * 4 « 444 444 44

The image capturing device 2 comprises light sources (not shown) corresponding to the light sources 2b shown in FIG. 2 and three cameras 2a arranged along the transverse direction of the initial polarizing film strip 1. In Fig. 4, the cameras are arranged in a single row. However, this is not the only option, cameras can be arranged in two or more rows. Similarly, the number of cameras 2a arranged along the transverse direction is not particularly limited. The camera may be one, or it may be two, three, four or more. The camera 2a includes, as an image sensing element, a one-dimensional CCD sensor in which 5000 pixels are arranged in a very dense state. In one example, the width of the initial polarizing film web 1 to be inspected is approximately 1300 mm, and the size of the inspection area of the image capturing device 2 is approximately 1300 mm in the transverse direction of the initial polarizing film web 1.

[0059]

The image processing device 14 processes the image data captured by the camera 2a and detects whether or not there is a defect within the initial polarizing film strip 7. The entire polarizing film initial web 1 is segmented into a plurality of regions along the dividing lines parallel to the transverse direction of the polarizing film initial web 1. Of these areas (in Figure 5 each of 100mm in the longitudinal direction of the initial polarizing film web), the area in which the presence of defect is detected is divided into a plurality of sections (in the example of Figure 5 each section is square with side 20 mm) arranged in a grid pattern. The image data of the defect-containing area is converted to binary data indicating whether or not the defect-containing section comprises a defect in a binary manner (the defect-containing section information is represented in black, and the defect-free section information is represented in white). In one

01-2308-I0-Eng

As an example, the image processing apparatus 14 converts the image data shown in Fig. 5 (a) relating to the defective block 002 (defect area) on the initial polarizing film strip 1 shown in Fig. 4 to binary data relating to the defective block 002 shown in Fig. FIG. 5 (b). The obtained binary data is passed to the barcode control device 15 via the data processing device 14. The image processing device 14 may be formed by an image processing program and a computer executing the image processing program. The image processing program may include customized various known algorithms, such as a defect detection algorithm. Alternatively, the image processing device 14 may be formed by hardware.

[0060]

The barcode control device 15 converts the binary data supplied by the image processing device 14 to defect position data in which the defect-containing section (black section) is represented by "1" and the defect-free section (white section) is represented by "0". The plurality of sections on which the defect-containing region is segmented into a grid pattern is arranged in a matrix m times n, where m is the number of sections arranged along the longitudinal direction of the polarizing film initial web 1 and n is the number of sections arranged along the transverse direction of the polarizing film initial web 1; (in the example shown in Fig. 5jem = 5an = 9). As shown in Fig. 5 (c), the binary code string related to defective block 002 is formed by binary code strings corresponding to respective small blocks (in the example shown in Fig. 5 small blocks 01 to 05), each of which is formed by sections arranged in the matrix one time n, where one (1) is the number of sections located in the longitudinal direction of the initial strip 1 of the polarizing film and n is the number of sections arranged along the transverse direction of the initial strip 1

01-2308-10-Eng

-25 • ·

• ·· polarizing film. The binary code string of each small block includes, from the most significant bit position: a data string indicating the number of the defective block that represents the sequence number of the region containing the defect assigned to that region in the order of regions detected in the polarization film starting band 1 (in the example shown in FIG. 3 bits); a data string indicating the number of the small block (2 bits in the example shown in FIG. 5); and a binary code string indicating whether or not the section contains a defect (the presence of the defect is represented by "1 and the absence of the defect is represented by" 0) (in the example shown in Fig. 5 it is 9 bits). The barcode control device 15 stores the position data in a data CD (CD-R) 16 which serves as a storage medium. The barcode control device 15 is implemented, for example, as a personal computer or the like. Data indicating whether or not a section contains a defect is not limited to binary code. A hexadecimal number or the like may be used to write data about a plurality of image processing devices. For example, data indicating whether or not a section contains a defect may represent: if a defect is detected by the first image processing device, it is represented by "1; in the case where a defect is detected by the second image processing device, it is represented by "2; in the case where a defect is detected by a third image processing device, it is represented by "4; and in the case where the defect is detected simultaneously by the plurality of image processing devices, it is represented by the sum of the numbers representing the cases where the defect is detected by the respective image processing device. If the defect is detected simultaneously by the first image processing device and the third image processing device, the data indicating whether or not the defect is present is represented by “5. By assigning individual values to the inspection results

01-2308-10-Eng

-26v - The device enabled by the image processing equipment is distinguished by the marking device when the marking performs the following defect position calculation which the image processing device has detected defect. This allows only a defect detected by a particular image processing device to be marked.

[0061]

The barcode control device 15 further drives the barcode printer 18 in accordance with the binary data acquired by the image processing device 14. Upon receiving the binary data relating to the defect area from the image processing device 14, the bar code control device 15 generates bar code data indicating the number of defective blocks. The number of defective blocks is the number that represents the number of times the barcode control device 15 has received binary data relating to a region containing a defect in the same polarizing film starting band 1. After the prescribed time has elapsed from receiving the binary data from the image processing device 14 relating to the defect area, the barcode control device 15 sends the print command and the barcode data to the barcode printer 18. The predetermined time is set such that the timing of printing of the barcode 17 by the barcode printer 18 is synchronized with the timing of the front portion of the barcode 17-associated region passing through the print position of the barcode printer 18 during transport of the initial polarizing film strip.

[0062]

The barcode printer 18 is not particularly limited. It can be an inkjet printer. Upon receipt of the print command and the bar code printing data from the bar code control device 15, the bar code printer 18 prints the bar codes 17 representing the defective block number to the default

01-2308-10-Eng

-2Ίstrip 4 of the polarizing film on the end portion in the transverse direction. Thus, the barcode printer 18 can print, on the initial strip of polarizing film at the end portion in the transverse direction, a barcode 17 representing the defective block number at the front of the area corresponding to the defective block number.

[0063] Further ίθ in detail described example steps Ξ6 to Ξ10 on FIG Fig. 6 to 8. [0064] How Yippee shown in Fig. 8, the polarizing film 4 is unwound that scroll 13 with the help of transport rollers

(not shown) and the like, and a release film 21 is laminated to the initial polarizing film web 4 to form the initial polarizing film web 22.

The obtained polarizing film precursor strip 22 is conveyed to the marking apparatus and then wound onto a roll 29.

[0065]

The release film marking device 21 produces markers 32 (see c arranged on the polarizing film starting band 22. As shown in FIG. 8, the marking device includes a sensor 23, a barcode scanner 24, a drive 26, a marker 27 and a disc. HDD drive device (Rag Disc Markers [0066]

A sensor 23 and a coding device (not shown), which is located near the markers 27, measure the conveying speed of the initial signal to the polarizing film strip 22 and transmit the PCs 25 (Personal Computer).

timers [0067]

The barcode reader 24 reads the barcodes 17 printed on the starting strip 22 of the polarizing film in the transverse direction, and passes the defective block number represented by the barcode

Ol-2308-10-Ce

-28 by code 17 to the PC 25 via transmission, for example, RS232C.

[0068]

The PC 25 passes the command to the barcode reader 24, receives the defective block number from the barcode reader 24, and reads the defect position data stored on the data CD 16. The PC 25 then verifies the defective block number with position information data to specify (calculate) the polarization film defect position based on the defect location data associated with the defective block number. As a result of this calculation, for example, PC 25 obtains binary data from the defect position data shown in Fig. 7 (a). The binary data indicates, as shown in Fig. 7 (b), whether or not the defect area comprises a defect in a binary manner (the defect-containing section information is represented in black, and the defect-free section information is represented in white) ). Based on the binary data, the PC 25 transmits the command of the marker control device 28 (see FIG. 6), which controls the markers 27 positioned so as to grip the sections between each other in the transverse direction (for example black in FIG. 5 (b)) sections) containing a defect.

[0069]

The PC 25 receives a start / stop command to create a mark from the marker control device 28 (see FIG. 6). In response to the start / stop command, the marker control device 28 (see FIG. 6) acknowledges the response to the start / stop command and response, and then passes the tagging command to the marker control device 28 (see FIG. 6) at the appropriate timing. Here, the PC 25 controls the timing of the handover of the tagging command in accordance with the outputs of the sensor 23 and the encoder (not shown) so as to synchronize the timing of the barcode reading by the barcode reader 24

01-2308-10-Eng

-29s the timing of tagging by markers 27. The program that controls the operation of the PC 25 is stored in the HDD 26.

[0070]

The markers 27 are markers (commercially available, for example, as "magic ink (registered trade mark)") and are arranged with respect to the barcode reader 24 further downstream of the initial polarizing film strip 22. A plurality of markers 27 are spaced apart along the transverse direction of the initial polarizing film web 1. The distance is equal to the size of the section (20 mm in FIG. 6) used to obtain the defect position data. The number of markers 27 is large enough to operate over the entire width of the initial polarizing film web 22. This number is preferably, for example, seventy-five. The markers 27 may form linear marks 32 on the surface of the initial strip 22 of the polarizing film parallel to the conveying direction of the surface of the initial strip 22.

The marks 32 come into contact

Advantageously, they may be formed by bringing the surface of the starting web 22 out of use when the markers 27 are obstructed so that the ability to write markers by evaporation of solvent, diluent and size of marks 32 formed may be limited, if visually, for example linear marks, min. In the tip of the polarizing film markers 27.

for example and the like.

markers 27

Shapes recognized. Markers 32 each having the length of the present embodiment are used as markers. As markers 27, known markers of various types, such as ink markers 27, can be generally used markers, markers which make cuts and the like as marks 32 on the initial strip 22 of the polarizing film.

[0071]

In accordance with the tagging command from the PC 25 indicating the section (in the example in Fig. 7 (b) the black section) containing the defect, the marker control device 28 selectively controlled the marker

01-2308-10-Eng

-3027 positioned so as to grip the section from both sides in a transverse direction. The controlled markers 27 form marks 32 in such a way that the defect marking section is clamped between marks 32 on both sides in the transverse direction. As a result, on the surface of the initial polarizing film web 22, the defect-containing portion is clamped between two linear marks 32, as shown in Fig. 7 (c).

[0072]

Depending on the direction in which the polarizing film precursor strip 22 is fed from the roll 13, a plurality of areas containing a defect on the initial polarizing film precursor strip 22 may be fed to the marking apparatus in descending order of the numbers of defective blocks of these areas. The marking device itself automatically detects the direction in which the polarizing film starting strip 22 is fed based on the defective block numbers, by reversing the order of the defect position data in accordance with the direction in which the polarizing film starting strip 22 is fed.

[0073]

The initial strip 22 of the polarizing film, indicated by the marking device 32, is then cut into a plurality of defined areas (areas defined by the dashed lines in Fig. 3) having prescribed shapes (in this example rectangles) as shown in Fig. 3. the defined surfaces serve as polarizing films having shapes and sizes depending on the application. The polarizing films 31 are inspected to determine whether or not they contain the marks 32 and are manually or by a sorting device categorized into polarizing films 31 with the marks 32 and polarizing films without the marks 32. When checking whether the polarizing films 31 contain the marks 32 or not, The marks 32 that grip the defect from both sides allow easy detection even of defects that are visually

01-2308-10-Eng

-31 difficult to recognize. On the polarized film films 31, the defects in step S11 are visually verified.

The visual inspection in step S11 is used to determine whether or not the polarization defects are tolerable.

If the defects of the polarizing films 31 are determined to be tolerable, a visual inspection of the polarizing film is performed in a short check time in a step S12, and the polarizing films are shipped as a product.

On the other hand, if the polarizing film defects are determined to be intolerable, the polarizing films are in the mark step

S14 discarded. Meanwhile, the polarizing films 31 of step Ξ12 are visually in

uncontrolled and shipped as a product.

In the embodiment described above, a one-dimensional barcode representing the defective block number is printed as an identification code. However, if the defect can be recognized on a region (defective block) containing a unique identification base, the identification code of the present invention is not limited to a one-dimensional barcode.

It may be in the form of a two-dimensional bar code, a symbol (for example, a numeric character indicating the number of the defective block) and the like.

Furthermore, in the embodiment described above, the defect position of the polarizing film is identified based on both the identification code (barcode) and the defect position data. However, in the inspection method of the present invention, the defect position on the polarizing film may alternatively be specified based only on the defect position data. In addition, when an identification code is used in specifying the defect position of the polarizing film, the identification code may represent, in addition to the area number containing the defects, the defect content, the defect position coordinates and the like.

-2308-10-Nr

As described above, the method of inspecting the polarizing film of the present invention provides the effect that the mark may be formed adjacent to the detected defect by the defect inspection device without causing the portion of the polarizing film to contain, as all defects detected by the inspection device. defects, at least one tolerable defect was unusable as a product.

[0077]

The specific embodiments and examples discussed in the aforementioned best embodiment of the invention serve exclusively to illustrate the technical details of the present invention, which are not to be construed narrowly within the scope of these specific embodiments and examples, but may be applied in a number of variations within of the claims below.

Industrial Applicability

The present invention can be used in the production of various polarizing films.

Claims (4)

01-2308-10-Eng PATENT CLAIMS A method of controlling a polarizing film comprising the steps of: detecting a defect in the strip-like polarizing film by means of a defect inspection device; recording the defect position by creating, based on the result of the defect detection, defect position data indicating the defect position, and storing the defect position data in a storage medium; winding the polarizing film in the form of a strip into the roll after detecting the defect; unwinding the polarizing film in the form of a strip from a roll; laminating another film to a polarizing film in the form of a strip unwound from a roll; and forming a mark by (i) reading the defect position data stored in the storage medium after the next film is laminated, (ii) defining the polarizing film defect position based on the read defect position data, and (iii) creating the mark on the next film adjacent the defect according to the specified defect position. The method of claim 1, wherein the step of recording the position of the defects comprises: printing an identification code on the polarizing film at the end portion of the polarizing film in the transverse direction, based on the result of the defect detection, wherein the identification code identifies the area containing the defect between the regions to which the entire polarizing film is segmented according to dividing lines parallel to the transverse direction ilmu; generating the defect position data as defect position data in the defect-containing area; and -34 storing the defect location data in a storage medium associated with the defect-containing area, and the step of generating the marks comprises: reading the identification code on the polarizing film; and specifying the defect position of the polarizing film based on the defect position data associated with the area identified by the read identification code. The method of claim 2, further comprising the step of performing a treatment of the polarizing film in the end portion in the transverse direction by means of a corona discharge before the identification code is printed. The method of controlling a polarizing film according to any one of claims 1 to 3, wherein in the step of forming the mark, the mark is formed using a plurality of markers arranged along the transverse direction of the polarizing film.