KR20100079258A - Method for removing defects of polarizing plate and system - Google Patents

Abstract

PURPOSE: A method for removing defects of a polarizing plate and a system thereof are provided to remarkably improve the yield rate and productivity of a defect avoidance cutting unit. CONSTITUTION: A withdrawal unit(10) enables the movement of a polarizing plate(11) to a detection unit(30), and a division width is inputted to a data input unit(20) before detecting the defect of the polarized plate. A location information control unit(40) recognizes the division including the defect, and the location information of an end portion of division of which orientation direction coordinates are identical to the defect coordinates. A marking unit(50) performs marking operation by receiving the location information of the end portion.

Description

Fault elimination method of polarizer and system embodying it {METHOD FOR REMOVING DEFECTS OF POLARIZING PLATE AND SYSTEM}

The present invention relates to a method for removing defects of a polarizing plate and a system in which the method is implemented, which can improve the workability and stability of defect detection of a partitioned sheet-shaped polarizing plate and greatly improve the yield and productivity of defect avoidance cutting.

Polarizers are applied to optical devices such as liquid crystal display devices (LCDs).

The polarizing plate is a polarizer protective film represented by a triacetyl cellulose (TAC) on one side or both sides of a polyvinyl alcohol-based polarizer (or 'polarizing film'), laminated on the polarizer protective film It has a multi-layer structure in which an adhesive layer, a release film, a surface protective film or a functional coating layer is laminated.

This multi-layered polarizing plate is manufactured as a sheet-shaped product wound on a roll, and used to be cut into a single polarizing plate depending on the use, the process is as follows.

First, the defect which exists in a sheet-like polarizing plate is detected. In general, sheet-shaped polarizers include minute scratches caused by frictional force by an application device such as rollers, minute deformations such as bending or warping, foreign matters generated or generated during bubble formation, transportation, or processing. Defects exist, which degrade the optical quality of the liquid crystal display. Therefore, the defect of a sheet-shaped polarizing plate is detected, it marks on the defect site, and it winds up again on a roll, and stores. The sheet-shaped polarizing plate marked according to the use and the user's request is cut or punched into a sheet.

As a method of inspecting a defect of a polarizing plate, Japanese Laid-Open Patent Publication No. 2002-303580 (October 18, 2002) discloses a method of detecting a defect in a sheet-like product and scratching and marking a portion where the defect is detected. . However, the workability is not good because the marked sheet-like product must be completely inspected again in order to read the flaw marked defect position, and it is not economical in terms of cost because the reading device must be provided throughout the width direction of the sheet-like product.

In order to solve this problem, Japanese Patent Laid-Open Nos. 2008-200788 and 2005-062165 disclose a method of marking a defect position at a widthwise end portion of a sheet-like product. However, the sheet-shaped polarizing plate may be divided into two or more in the stretching direction according to the use and size of the final product, and if a defect location is marked at the end of the polarizing plate without considering each compartment, a defect is included in a certain compartment. It is difficult to read clearly. Therefore, only the marked defect information is read, the polarizing plate is cut and then inspected again to remove the sheet containing the defect, and the polarizing plate of the defect free compartment may be cut unnecessarily.

In particular, in recent years, LCD panels have become larger in size, and accordingly, the use of extended-length polarizing plates has increased. When the sheet-like polarizing plate is manufactured using such a long polarizing plate, the sheet-like polarizing plate may be partitioned into a plurality of planes in the stretching direction, thereby making it possible to manufacture more single polarizing plates without defects in one process.

Therefore, there is a further need for a technique capable of efficiently manufacturing a plurality of sheets of polarizing plates in which sheet-shaped polarizing plates are partitioned and defects are removed therefrom.

The present invention improves the workability and stability of defect detection of a polarizing plate without re-inspecting the sheet-shaped polarizing plate marked with defects, and greatly improves the production yield and productivity of a plurality of single-sheet polarizing plates without defects. An object of the present invention is to provide a method for removing a defect.

In addition, another object of the present invention is to provide a system in which the defect removal method of the polarizing plate is implemented.

In order to achieve the above object, the present invention provides a defect elimination method of a sheet-shaped polarizing plate partitioned in the stretching direction, recognizing the partition containing the defect, and at the end of the partition in which the coordinates of the defect and the stretching direction coincide. It provides a defect removal method of the polarizing plate comprising the step of marking.

In addition, the present invention provides a defect elimination system of a sheet-shaped polarizing plate in which a partition is defined in the stretching direction, comprising: detection means for detecting a defect of a sheet-shaped polarizing plate; Position information control means for recognizing a section containing the detected defect and generating coordinates of an end of the section in which the coordinates of the defect and the coordinates in the stretching direction coincide; And it provides a defect removal system of the polarizing plate is provided with marking means for displaying the position information of the generated end.

According to the present invention, it is possible to improve the workability and stability of defect detection, and to greatly improve the yield and productivity of defect avoidance in removing defects from a polarizing plate that is partitioned on two or more surfaces, and different defect determination conditions and marking methods. Not only can it be adjusted to meet the needs of each user, but also the manufacturing cost can be lowered by simplifying the defect reading means.

In addition, defect inspection, partitioning (slit cutting), and defect avoidance cutting process of sheet-shaped polarizing plates can be easily performed on an in-line, and a plurality of sheets of polarizing plates without defects are gradually increasing in size. In particular, the effect is anticipated further at the time of manufacture of a top plate polarizing plate.

The present invention relates to a method for removing defects of a polarizing plate and a system in which the method is implemented, which can improve the workability and stability of defect detection of a partitioned sheet-shaped polarizing plate and greatly improve the yield and productivity of defect avoidance cutting.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The polarizing plate includes a polarizer, one side of the polarizer is a polarizer protective film for protecting the polarizer, a pressure-sensitive adhesive layer and a release film to be affixed with the liquid crystal cell is laminated in order, the other side of the polarizer protective film It has a multilayer structure provided.

As a polarizer, the thing in which the dichroic dye was adsorption-oriented to the film which consists of PVA resin can be used. As PVA resin which comprises a polarizer, the copolymer of polyvinyl acetate which is a homopolymer of vinyl acetate, and vinyl acetate and the other monomer copolymerizable with this can be used. In this case, examples of the other monomer copolymerizable with vinyl acetate include unsaturated carboxylic acids, unsaturated sulfonic acids, olefins, vinyl ethers, and acrylamides having an ammonium group.

The polarizer protective film is preferably excellent in transparency, mechanical strength, thermal stability, moisture shielding, isotropy, etc., for example, polyester-based films such as polyethylene terephthalate, polyethylene isophthalate, polybutylene terephthalate; Cellulose films such as diacetyl cellulose and triacetyl cellulose; Polycarbonate film; Acrylic films such as polymethyl (meth) acrylate and polyethyl (meth) acrylate; Styrene films such as polystyrene and acrylonitrile-styrene copolymers; Polyolefin-based films such as polyethylene, polypropylene, cyclo- or polyolefin-based films having a norbornene structure, and ethylene propylene copolymers; Polyimide film; Polyether sulfone-based film; Sulfone type films and the like can be used.

The pressure-sensitive adhesive layer is acrylic copolymer, natural rubber, styrene-isoprene-styrene (SIS) block copolymer, styrene-butadiene-styrene (SBS) block copolymer, styrene-ethylenebutylene-styrene (SEBS) block copolymer, styrene- It may be formed using conventional polymers such as butadiene rubber, polybutadiene, polyisoprene, polyisobutylene, butyl rubber, chloroprene rubber, silicone rubber and the like.

The release film is not particularly limited as long as it is a film commonly used in the art, and specific examples thereof include polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, and ethylene-propylene copolymer. Polyolefin-based films such as ethylene-1-butene copolymer, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer and ethylene-vinyl alcohol copolymer; Polyester-based films such as polyethylene terephthalate, polyethylene naphthalate and polybutylene terephthalate; Polyamide films such as polyacrylate, polystyrene, nylon 6 and partially aromatic polyamide; Polyvinyl chloride film; Polyvinylidene chloride film; Or polycarbonate films. These can be appropriately released by silicon-based, fluorine-based, silica powder or the like.

In addition, the polarizing plate may further include an optical film such as a surface protection film, a reflecting plate, a transflective plate, a retardation plate, a viewing angle compensation film, and the like. Each film constituting the polarizing plate may have a hard coating layer and a pollution prevention layer as necessary. A functional layer such as an antistatic layer, an antireflection layer, an antiglare layer, or a diffusion layer may be further formed.

The multi-layered polarizing plate is wound on a roll in a sheet shape, and then cut into a single polarizing plate according to a use to be used for manufacturing a liquid crystal display panel.

In the present invention, a polarizing plate having a conventional structure as a sheet-like product is described, but a polarizing plate having a functional coating layer such as an antiglare layer, an antireflection layer, a diffusion layer, or a reflecting plate, a semi-transmissive plate, a phase difference plate, a viewing angle compensation film Naturally, it can be applied also to the polarizing plate in which various optical layers, such as these, were laminated | stacked, and it is applicable to all the sheet-shaped products other than a polarizing plate.

In the present invention, the 'defect' of the polarizing plate means a minute scratches, micro deformations such as bending or warping, generation of bubbles and cracks, incorporation of foreign matter on the surface or inside, scratches or contamination, etc., but are not limited thereto. .

In addition, a "sheet-shaped polarizing plate" means the normal polarizing plate wound by the roll.

In addition, "compartment" means dividing the sheet-like polarizing plate to have two or more partitions (a, b) in the stretching direction, as shown in FIG.

In addition, "compartment width" means the value (a ', b') of the width of each surface in the width direction for dividing the sheet-like polarizing plate into two or more surfaces (a, b) in the stretching direction.

In addition, the “compartment polarizing plate” is a polarizing plate obtained by slit cutting a sheet-shaped polarizing plate according to a partition width, and means a polarizing plate having the same length as that of the sheet-shaped polarizing plate and having a widthwise length reduced to a partition width. For example, the partition polarizing plate obtained by partitioning the sheet-shaped polarizing plate to have three sides has the same stretching direction length as the sheet-shaped polarizing plate and has a widthwise length of 1/3 of the sheet-shaped polarizing plate.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention. In this case, in the description of the present invention, a description of a known configuration or a function thereof is omitted to clarify the gist of the present invention.

Defect removal method of the polarizing plate of the present invention is characterized in that it comprises a step of recognizing the section containing the defect in the stretching direction, and marking the end of the section that the coordinates of the defect coordinate and the stretching direction coincide.

In addition, the defect removal method of the polarizing plate of the present invention includes means for detecting a defect of the sheet-shaped polarizing plate; Position information control means for recognizing a section containing the detected defect and generating coordinates of an end of the section in which the coordinates of the defect and the coordinates in the stretching direction coincide; And means for marking the position information of the generated end.

More specifically, as shown in Figure 2, the process of the defect removal method of the polarizing plate according to an embodiment of the present invention after inputting the partition width of the sheet-shaped polarizing plate to detect and mark the defect, and to read the detected defect It is a method including the step of avoiding cutting.

In addition, the defect removal method of the polarizing plate may include means for drawing out a sheet-shaped polarizing plate; Data input means for inputting a partition width of the drawn polarizing plate; Means for detecting a defect of the polarizing plate; Position information control means for recognizing a section containing the detected defect and generating position information of an end portion of the section in which the coordinate of the defect and the coordinate in the stretching direction coincide; Means for marking position information of the generated end portion; Winding means for winding the marked sheet polarizing plate with a roll; Means for withdrawing the marked sheet polarizing plate from the roll; First cutting means for cutting the marked sheet polarizing plate to produce respective partition polarizing plates; Means for reading the marking at the end of each compartment polarizer; And a second cutting means for cutting each partition polarizer according to the read information.

3 illustrates a system in which a part of a method for removing defects of a polarizing plate partitioned into two surfaces in a drawing direction is implemented according to an embodiment of the present invention.

First, the sheet-shaped polarizing plate 11 wound on a roll is drawn out and moved through the drawing means 10 to inspect the defect. In the drawn polarizing plate, a plurality of rollers are arranged horizontally, and each roller is moved to the detecting means 30 by means for moving the polarizing plate while rotating each roller. The drawing means 10 is not particularly limited as long as it is a means capable of releasing the wound sheet.

Before detecting the defect of the drawn sheet-shaped polarizing plate, the division widths a 'and b' are input into the data input means 20 so that the sheet-shaped polarizing plate may be divided into two surfaces a and b. The data input means 20 is provided in the detection means 30 or in front of the detection means 30 to be interlocked with each other, and in addition to the partition width, the condition according to the user's request, for example, the size, shape, type, etc. Data can be input to detect defects.

When the division of a sheet-shaped polarizing plate is determined, the defect of a polarizing plate is detected. The defect detecting means 30 is a means using a method similar to a known image processing technique, wherein an image acquired by a camera or the like is sent to an image processing unit (not shown), and the surface or inside of the sheet-shaped polarizing plate using the image processing technique. Defects present in the system are detected. The image processing unit may be configured by software or hardware such as an image processing program. The image processing unit determines whether or not a defect is present and also detects the position of the defect. In addition, when it is performed by an image processing program, a known defect determination algorithm can be used.

When a defect is detected, the position information control means 40 interlocked with the data input means 20 and the detection means 30 recognizes the section containing the defect, and the coordinates of the defect coordinates and the stretching direction coincide with each other. The location information of the end of the compartment is generated and recorded. In addition to the positional information of the end, other information detected according to the input data according to the user's request may be generated and recorded.

When the position information of the defect is generated, the marking means 50 receives and marks the position information of the end generated from the position information control means 40 which is linked thereto. Specifically, when a defect 51a is detected in one partition surface a of two partition surfaces, it becomes the marking 52a at the edge part of the partition surface a containing the defect 51a. On the contrary, if a defect 51b is detected in the other partition surface b, it will be marked on the edge part 52b of the partition surface b containing the defect 51b. In addition, in order to confirm that the defect coordinates and the partition end coordinates coincide in the stretching direction, not only the edges 52a and 52b of the partition surface but also the coordinates of the defects 51a and 51b in the partition surface can be marked together. Different types, methods, sizes or colors may be used for marking. Therefore, the marking means 50 may be provided at the end of each section, or may be provided over the width direction of the sheet-shaped polarizing plate. In addition, the type, method, size, or color of the marking may be adjusted differently according to a condition according to a user's request, and may be marked at any one of the two ends existing in each compartment.

The marking of the sheet-shaped polarizing plate is completed can be wound and stored in a roll by the winding means 60, or may be directly used for the production of the partition polarizing plate.

4 illustrates a system in which a part of a method for removing defects of a polarizing plate partitioned into three surfaces in a drawing direction is implemented according to another exemplary embodiment of the present invention.

The defect removal method described above with reference to FIG. 3 except that the partition widths a 'and b'c' are input to the data input means 20 so that the sheet-shaped polarizers are divided into three surfaces a, b and c. As shown.

In addition, the defect removal method of the polarizing plate partitioned in four planes in the stretching direction is also natural as described with reference to FIGS. 2 and 3.

The defect removal method including the marking as described above recognizes a compartment containing a defect among a plurality of compartments, and marks the end of the compartment in which the coordinates of the defect coincide with the coordinates in the stretching direction. Stability can be improved.

5 and 6 illustrate a system in which a defect avoidance cutting step of a marked sheet polarizer is partitioned into three surfaces in the drawing direction according to an embodiment of the present invention.

The polarizing plate marked through the marking step or the sheet-shaped polarizing plate wound on the roll after being marked is manufactured into each partition polarizing plate by cutting. The sheet-shaped polarizing plate is cut by the first cutting means 70 which is interlocked with the data input means 20 and manufactured into three compartment polarizing plates. The cutting means is not particularly limited as long as it is a known cutter, and it is preferable to use a laser cutter in order to prevent a defect of the cutting surface.

As shown in FIG. 5, the three compartment polarizing plates produced by cutting can each be wound on the roll again by three winding means 60, or can be moved directly to the step shown in FIG. 6 without being wound up. . In addition, the both ends (not shown) of the width direction of the discarded sheet-shaped polarizing plate other than what is produced by a partitioned polarizing plate at the time of cutting | disconnection are wound by the separate winding means 60 '.

As shown in FIG. 6, the partition polarizing plate 11 'wound by the roll is a polarizing plate in which the defect is marked at the edge part, and the defect position coordinate was marked together as needed.

The marking of the edge of the partition polarizer is read by the reading means 80. After reading the position coordinates of the defect, the type, size, and shape of the defect, the cutting position of the partition polarizer is determined, and the result is second cut through the network. To the means 90. At this time, the reading can be read only at the end of the partition polarizing plate in which marking is present without needing to be performed throughout the width direction of the partition polarizing plate. Therefore, the defect reading means 80 such as a sensor may be provided only at the end of the compartment polarizing plate, thereby lowering the cost of the device.

When the reading is completed, the reading information is transmitted to the second cutting means 90, through which defect avoidance cutting of the polarizing plate is performed. As the cutting method, a method such as cutter blade cutting, punching cutting, heating wire cutting or laser cutting can be used, and among these, laser cutting means capable of preventing defects in the cut surface is preferable.

At this time, the polarizing plate read and cut as defective is conveyed to the defective article conveying means 91 and discarded, and the polarizing plate read and cut as defective is stored and moved to the stacking means 92.

In FIG. 6, a step of avoiding cutting of one compartment polarizer among three compartment polarizers is illustrated, but the other two compartment polarizers are simultaneously processed in the same manner.

The defect removing method of the polarizing plate as described above is a method in which the marking step shown in Figs. 3 or 4 and the defect avoidance cutting step shown in Figs. 5 and 6 are continuously performed in the in-line, and the sheet-shaped polarizing plate is again marked after marking the defect of the sheet-shaped polarizing plate. It is not only possible to read the end of the compartment polarizer without having to read the markings throughout the width direction of, but also to cut off the compartment polarizer and retest to find the sheet containing the defect. Therefore, the manufacturing yield and productivity of the multiple sheet | seat polarizing plate of defect-free from a sheet-shaped polarizing plate can be improved.

Hereinafter, preferred examples are provided to aid the understanding of the present invention, but the following examples are merely for exemplifying the present invention, and it will be apparent to those skilled in the art that various changes and modifications can be made within the scope and spirit of the present invention. It is natural that such variations and modifications fall within the scope of the appended claims.

<Defect Marking of Sheet-shaped Polarizing Plates>

Example 1

In the system as shown in FIG. 3, the defect of the sheet-shaped polarizing plate wound on the roll was inspected and marked. First, the division width of the polarizing plate was input to the data input means 20 so that the polarizing plate could be divided into two surfaces. Subsequently, the sheet-shaped polarizing plate wound on the roll was released using the polarizing plate extracting means 10 and moved to the defect detecting means 30 provided with a camera and an image processing part continuously, and the defect was detected. When a defect is detected, the position information generation unit 40 recognizes the section containing the defect and generates position information at which the coordinates of the defect coordinate and the stretching direction coincide at the end of the section. Marking defect coordinates and ends at the same time through the generated information, but the color was performed differently. The sheet-shaped polarizing plate on which marking was completed was wound again into a roll shape by using the winding means 40.

Example 2

Except that the partition width value is input so that the polarizing plate is partitioned into three planes, it was carried out in the same manner as in Example 1 (see Fig. 4).

<Cutting defect avoidance from marked polarizer>

Example 3

The marked sheet-shaped polarizing plate prepared in Example 1 was taken out, cut according to the input partition width, and manufactured into two compartment polarizing plates. At this time, by using a CO ₂ laser cutting machine was cut at an output of 100-400W. Each of the two compartment polarizers was moved to the reading means 80 to read the markings at the ends and determine the cutting position. At this time, the reading means 80 used a sensor provided at the end to read the marking of the end of the partition polarizing plate. After the reading was completed, each compartment polarizer was cut at a power of 100-400 W using a CO ₂ laser cutter according to the determined cutting position. At this time, the polarizing plate which was read and cut as having no defect was transferred to the storage means 92, and stored.

Example 4

The same procedure was followed as in Example 3, except that three compartment polarizers were manufactured using the marked sheet polarizers prepared in Example 2.

As shown in Examples 1 to 4, after inputting the partition width of the sheet-shaped polarizing plate, the defect is inspected, the compartment containing the defect is recognized, and at the end of the compartment where the defect coordinate and the coordinate in the stretching direction coincide. By marking, the manufacturing yield and productivity of the multiple sheet | seat polarizing plate without a defect were improved.

1 is a view showing a sheet-shaped polarizing plate is partitioned according to an embodiment of the present invention,

2 is a view showing a process of the defect removal method of the polarizing plate according to an embodiment of the present invention,

FIG. 3 is a diagram illustrating a system in which a defect marking is implemented, which is a part of a defect removal method of a polarizer according to an embodiment of the present invention;

FIG. 4 is a diagram illustrating a system in which a defect marking is implemented, which is a part of a defect removal method of a polarizer according to another embodiment of the present invention;

5 and 6 are diagrams illustrating a system in which a defect avoidance cutting step, which is a part of a defect removal method of a polarizer according to an embodiment of the present invention, is implemented.

Explanation of symbols on the main parts of the drawings

a, b, c: compartment a ', b', c ': compartment width

10: drawing-out means 11: sheet-shaped polarizing plate

11 ': Marked sheet-shaped polarizing plate 20: Data input means

30: detection means 40: position information control means

50: marking means 51a, 51b, 51c: defect position coordinates

52a, 52b, 52c: end position coordinates 60, 60 ': winding means

70: first cutting means 80: reading means

90: second cutting means 91: defective product conveying means

92: loading means

Claims (16)

A method for removing defects of a sheet-shaped polarizing plate in which a partition is scheduled in a drawing direction, the method comprising: recognizing a section containing a defect and marking the end of the section in which the coordinate of the defect coincides with the defect coordinate. Way. The method of claim 1, further comprising: inputting a partition width of the sheet-shaped polarizing plate before the marking step. The method for removing defects of a polarizing plate according to claim 1, wherein the polarizing plate is marked at the same time and at the defect coordinates. The method of claim 1, further comprising, after the marking step, slit-cutting the sheet-shaped polarizing plate to manufacture each partition polarizing plate. 5. The method of claim 4, comprising reading the markings at the ends of each compartment polarizer after fabricating the compartment polarizers. 6. The method of claim 5, comprising avoiding and cutting the defects of each of the partition polarizers read after the marking of the end of the partition polarizer. The method of claim 6, wherein after the avoiding cutting step, the defect-free polarizing plate is transferred to a loading means and the defective polarizing plate is transferred to a defective product conveying means. A defect elimination system of a sheet-shaped polarizing plate in which a partition is scheduled in the stretching direction, Detecting means for detecting a defect of the sheet-shaped polarizing plate; Position information control means for recognizing a section containing the detected defect and generating coordinates of an end of the section in which the coordinates of the defect and the coordinates in the stretching direction coincide; And The defect removal system of the polarizing plate provided with the marking means for displaying the position information of the generated end. 9. The system of claim 8, wherein said marking means is provided at the end of each compartment. The defect removal system of claim 8, wherein the marking means is provided over the width direction of the sheet-shaped polarizing plate. The defect elimination system of claim 8, further comprising data input means for inputting a partition width of a sheet-shaped polarizing plate to or in front of the detecting means. 10. The defect elimination system of claim 8, further comprising: first cutting means for cutting each sheet polarizing plate behind the marking unit to manufacture each of the divided polarizing plates. 13. The system of claim 12, wherein means for reading the marking of the end of each compartment polarizer is provided behind said first cutting means. The system of claim 13, wherein a second cutting means for avoiding and cutting a defect of each of the partition polarizing plates is provided behind the reading means. 15. The defect elimination system of claim 14, further comprising a loading means for storing the polarizing plate free of defects cut from each compartment polarizing plate behind the second cutting means. 15. The defect elimination system of claim 14, comprising defective conveyance means for conveying a defective polarizing plate avoided from each compartment polarizing plate behind said second cutting means.

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