TW201819965A - Polarizer, polarizing plate and image display device - Google Patents

Abstract

The present invention provides a polarizer that is less likely to crack with temperature changes. The means for solving the abovementioned problem is to adjust an average height Rc of roughness curve elements of an end face 2a of a film-like polarizer 2 to be 0.05 to 1.7 [mu]m.

Description

 Polarizer, polarizing plate and image display device  

The present invention relates to a polarizer, a polarizing plate, and an image display device.

In recent years, it has been required to reduce the thickness of an image display device including a liquid crystal cell or an organic EL device.

Therefore, the polarizer for the image display device is also formed into a thin film shape. Since the film-shaped polarizer is brittle and easily cracked, in order to protect the polarizer, a protective film is bonded to both surfaces of the polarizer when the polarizing plate is manufactured. In addition, in order to improve the dimensional accuracy of the polarizing plate, the end portion of the laminate including the protective film and the polarizer is polished (see, for example, Patent Document 1).

 [Previous Technical Literature]    [Patent Document]  

[Patent Document 1] Japanese Patent No. 3875331

In recent years, in order to reduce the thickness of the polarizing plate, development of a polarizing plate in which a protective film is bonded to only one surface of the polarizing plate has been carried out. However, the polarizer which is only laminated on one side of the protective film is more likely to be cracked (cracked) than the polarizer which is laminated on both sides of the protective film. Such cracking is caused by expansion or contraction of the polarizer as a function of temperature. In particular, it is known that cracking easily occurs due to a sharp temperature change (thermal shock) of the polarizer.

Moreover, in recent years, in order to improve design, the frame of the image display device is required to be narrow. Corresponding to such requirements, high dimensional accuracy is also required for the ends of the polarizing plates. In order to adjust the size of the polarizing plate with high precision, it is necessary to cut (grind) the end portion of the laminated body composed of the protective film, the polarizing plate, and the like with high precision. However, the polarizer of the single-sided laminated protective film is more likely to cause a burden on the end face of the polarizer at the time of cutting than the polarizer in which the protective film is superposed on both sides, and the end face of the polarizer is likely to be rough. The thickness of such an end face tends to cause cracking of the polarizer as the temperature changes. In particular, it is understood that the end face of the polarizer located on the surface side of the non-protective film is more likely to be broken than the end face of the polarizer located on the surface side of the superposed protective film.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a polarizing plate which is high in dimensional accuracy and which is less likely to be broken by temperature change, a polarizing plate including the polarizing plate, and an image display device including the polarizing plate.

In one embodiment of the present invention, the polarizer is a film-shaped polarizer, and the average height Rc of the thickness curve elements of the end faces of the polarizer is 0.05 to 1.7 μm. The average height Rc may also be 0.05 to 0.28 μm.

A polarizing plate according to an aspect of the present invention includes the above polarizing plate and a first optical film laminated on a surface of the polarizing plate.

In one aspect of the invention, the first side of the side of the polarizer that encloses one end face is adjacent to the first optical film, and the second side of the side that surrounds the end face is located on the opposite side of the first side The root mean square roughness Rq of the portion along the second side in the end face may be 0.03 to 0.15 μm.

In one aspect of the invention, the first optical film may also be a protective film.

The polarizing plate according to an aspect of the invention may further include: an adhesive layer laminated on the other surface of the polarizer; and a second optical film laminated on the adhesive layer.

The polarizing plate according to an aspect of the invention may further include: an adhesive layer laminated on the first optical film; and a second optical film laminated on the adhesive layer.

In one aspect of the invention, the second optical film may also be a reflective polarizer.

An image display device according to an aspect of the present invention includes the above polarizing plate.

According to the present invention, it is possible to provide a polarizer having high dimensional accuracy, which is less likely to be broken by temperature changes, a polarizing plate including the polarizer, and an image display device including the polarizing plate.

1‧‧‧Polar plate

2‧‧‧ Film-shaped polarizers

2a‧‧‧End face of polarizer

2as‧‧‧ Side of the end face (the part along the second side in the end face)

3‧‧‧Protective film (first optical film)

4‧‧‧Reflective polarizer (second optical film)

5‧‧‧ Pressure-sensitive adhesive layer

10‧‧‧Cutting tools

10a‧‧‧Support

100‧‧‧Layer

100a‧‧‧ end face

11a, 11b, 11c, 11d, 11e, 11f‧‧‧ cutting part

1A‧‧‧Polar plate

A‧‧‧ axis of rotation

B‧‧‧ cutting edge

S‧‧‧ cutting surface

S1‧‧‧ first side

S2‧‧‧ second side

S3‧‧‧ third side

S4‧‧‧ fourth side

Fig. 1(a) is a schematic perspective view of a polarizing plate according to an embodiment of the present invention, and Fig. 1(b) is a part of an end surface of the polarizing plate shown in Fig. 1(a). A schematic enlarged view of (part b).

Fig. 2 is a side view showing a cutting tool used in the production of a polarizing plate according to an embodiment of the present invention.

Fig. 3 is a front view of the cutting tool shown in Fig. 2.

Fig. 4 is a view showing the position of the cutting tool shown in Fig. 2 and the laminated body composed of a plurality of polarizing plates.

Fig. 5 is a view showing the position of a cutting tool shown in Fig. 3 and a laminated body composed of a plurality of polarizing plates.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the drawings, the same constituent elements are denoted by the same reference numerals. The present invention is not limited to the following embodiments. X, Y, and Z shown in the respective figures mean three coordinate axes that intersect each other perpendicularly. The directions indicated by the respective coordinate axes are common to all the figures. The ratios of dimensions and dimensions seen in the figures are not necessarily consistent with the actual ones.

 [Polarizer, polarizing plate and image display device]  

As shown in FIG. 1(a), the polarizing plate 1 of the present embodiment includes a film-shaped polarizing plate 2, a first optical film (3) superposed on one surface of the polarizing plate 2, and a superposed film. The pressure-sensitive adhesive layer 5 on the other surface of the polarizer 2 is laminated on the second optical film (4) of the pressure-sensitive adhesive layer 5. The first optical film is, for example, a protective film 3. The second optical film is, for example, a reflective polarizer 4. The polarizing plate 2 and the optical film and the layer provided in the polarizing plate 1 may be transparent. In the polarizing plate 1 of the present embodiment, the optical film (first optical film) is directly adhered to the polarizing film 2 via the adhesive layer without passing through the pressure-sensitive adhesive layer only on one surface of the polarizing plate 2.

The polarizer 2, the first optical film (3), the pressure-sensitive adhesive layer 5, and the second optical film (4) are each a rectangle having substantially the same size. The polarizing plate 1 as a whole is also a rectangular film. However, the respective shapes of the polarizer 2 and the polarizing plate 1 are different depending on the surface shape of the image display element to which the polarizing plate 1 is attached, and thus are not limited. The shape of each of the polarizer 2 and the polarizing plate 1 may be, for example, a polygonal shape, a circular shape, or an elliptical shape. A part or all of the outline of each of the polarizer 2 and the polarizing plate 1 may be a straight line or a curved line.

The image display device of the present embodiment may be, for example, a liquid crystal display device or an organic EL display device. The liquid crystal display device may include, for example, a liquid crystal cell, and a polarizing plate 1 attached to one surface or both surfaces of the liquid crystal cell. The organic EL display device may include, for example, an organic EL element and a polarizing plate 1 attached to the surface of the organic EL element. In the liquid crystal cell, two polarizing plates can usually be disposed. The polarizer provided in the polarizing plate disposed on the back side of the liquid crystal cell is more likely to be exposed to heat than the polarizer provided on the polarizing plate disposed on the viewing side of the liquid crystal cell. Therefore, when the polarizing plate 1 including the polarizing plate 2 of the present embodiment is disposed on the back side of the liquid crystal cell, cracking of the polarizing plate 2 with temperature change can be suppressed. The reason is as described later.

The average height Rc of the thickness curve elements of the end faces 2a of the polarizer 2 is 0.05 to 1.7 μm. The average height Rc may also be 0.05 to 0.28 μm, 0.07 to 1.7 μm, 0.07 to 1.604 μm, 0.07 to 1.0 μm, or 0.07 to 0.28 μm. The average height Rc of the thickness curve elements of the end face 2a can also be defined, for example, by the following formula 1.

In Formula 1, Rc is an average of the heights Zt of the thickness curve elements (contour curve elements) of the reference length 1. i is a natural number of 1 or more and m or less, and m is a natural number of 2 or more. Zti is the height of the i-th profile element of the reference length 1. The contour curve element refers to a group of adjacent mountains and valleys, and the height Zt of the contour curve element refers to the difference between a group of adjacent mountains (maximum values) and valleys (minimum values). Rc can be measured on the end face 2a of the polarizer 2 by, for example, a laser microscope.

The larger the average height Rc of the thickness curve elements of the end face 2a, in other words, the coarser the end face 2a, the more the end face 2a is unevenly deformed due to expansion or contraction with temperature. In particular, the end face 2a is unevenly and sharply deformed due to rapid expansion or contraction with thermal shock. When the polarizer 2 is extended in one axial direction or two axial directions, the expansion or contraction of the polarizer 2 is anisotropic. Due to these factors, as the temperature of the polarizer 2 changes, it is easy to cause cracking in the polarizer 2 with the end face 2a as a starting point. For example, a crack is generated starting from the valley of the contour curve element (that is, the deep recess of the end surface 2a). However, in the present embodiment, the average height Rc of the thickness curve elements of the end surface 2a is 0.05 to 1.7 μm, so that the respective cracking factors as described above can be reduced, and the polarizing plate 2 can be prevented from being cracked as the temperature changes. The length of the crack formed by the end face 2a having an average height Rc of 0.05 to 1.7 μm tends to be shorter than the length of the crack formed by the end face 2a having an average height Rc of more than 1.7 μm. When the protective film is adhered to both surfaces of the polarizer 2, the average height Rc of the roughness curve elements of the end face 2a of the polarizer 2 is almost uniform over the entire range of the end face 2a. On the other hand, when the protective film is adhered to only one side of the polarizer 2, the average height Rc of the thickness curve element of the end face 2a of the polarizer 2 is along with the interface away from the polarizer 2 and the protective film (followed) The tendency to become bigger. Since the polarizer 2 is a stretched film, it is easily cracked, and in particular, the end face of the polarizer located on the surface side of the unprotected film is liable to be roughened by the polishing blade treatment. Therefore, the average height Rc of the thickness curve elements of the end faces 2a of the polarizer 2 tends to become larger as it goes away from the interface between the polarizer 2 and the protective film. When the average height Rc of the thickness curve elements of the end surface 2a of the polarizer 2 is not uniform, the maximum value of the average height Rc of the thickness curve elements measured on the end surface 2a of the polarizer 2 may be, for example, 0.05 to 0.28. Mm. When the average height Rc of the thickness curve elements of the end face 2a of the polarizer 2 is not uniform, the length of the rupture formed by the end face 2a having a maximum value of the average height Rc of 0.05 to 0.28 μm is the largest than the average height Rc. The length of the crack formed by the end face 2a having a value larger than 0.28 μm tends to be shorter. Further, when the average height Rc of the thickness curve elements of the end faces 2a of the polarizer 2 is not uniform, the number of cracks formed by the end faces 2a having a maximum value of the average height Rc of 0.05 to 0.28 μm is higher than the average height Rc. The end face 2a whose maximum value is larger than 0.28 μm tends to have a smaller number of cracks.

When the end faces of the polarizer or the polarizing plate are not polished, the end faces of the polarizers are not roughened by polishing, so that the average height Rc of the end faces of the polarizers is substantially zero, and cracking is unlikely to occur at the end faces of the polarizers. In other words, the smaller the average height Rc of the end faces 2a, the less likely the crack is generated on the end faces of the polarizers. However, when the end faces of the polarizer or the polarizing plate are not polished, it is difficult to adjust the size of the polarizer or the polarizing plate to a desired value with high precision (for example, a range of tolerances of product specifications). Therefore, the accuracy of the size of the polarizer having an average height Rc of the end face 2a of less than 0.05 μm is worse than the accuracy of the size of the polarizer having an average height Rc of the end face 2a of 0.05 μm or more. In other words, the dimensional accuracy of the polarizer having the polished end face is higher than that of the polarizer having the unpolished end face.

The rectangular polarizer 2 has four end faces 2a. Among the plurality of end faces 2a of the polarizer 2, the average height Rc of the thickness curve elements of a part of the end faces 2a may be 0.05 to 1.7 μm. The average height Rc of the thickness curve elements of all the end faces 2a of the polarizer 2 may be 0.05 to 1.7 μm. The more the end faces 2a having an Rc of 0.05 to 1.7 μm, the more easily the occurrence of cracking of the polarizer 2 is suppressed.

As shown in (b) of FIG. 1, one end surface 2a of the polarizer 2 is surrounded by a first side S1, a second side S2, a third side S3, and a fourth side S4. In other words, the periphery of the end surface 2a is composed of the first side S1, the second side S2, the third side S3, and the fourth side S4. The first side S1 among the four sides of the enclosed end face 2a is adjacent to the protective film 3 (first optical film). The second side S2 among the four sides of the enclosed end face 2a is located on the opposite side of the first side S1. In other words, the second side S2 is adjacent to the pressure-sensitive adhesive layer 5. The second side S2 is a side that is not adjacent to the protective film 3.

The root mean square roughness Rq of the portion (2as) along the second side S2 in the end face 2a may be 0.03 to 0.50 μm. Hereinafter, the portion along the second side S2 of the end surface 2a is referred to as the "side portion 2as" of the end surface 2a. The root mean square roughness Rq may also be 0.03 to 0.466 μm, 0.03 to 0.30 μm, 0.03 to 0.15 μm, or 0.031 to 0.081 μm. The root mean square roughness Rq of the side portion 2as of the end surface 2a can be defined, for example, by the following formula 2.

In Formula 2, 1 (lowercase L of the English letter) is the reference length of the side portion 2as of the end face 2a. Z(x) is the height of the thickness curve of any position x on the reference length 1. Rq can be measured, for example, by a laser microscope at the side portion 2as of the end face 2a. In other words, Rq can be measured along the second side S2 of the end face 2a of the polarizer 2. The width of the side portion 2as in the thickness direction (Z-axis direction) of the polarizer 2 is not limited as long as Rq can be measured. If the end face 2a of the polarizer 2 is divided into two regions by the middle (center) of the first side S1 and the second side S2, Rq can be said to represent the second side S2 of the two regions without the protective film 3. An indicator of the mechanical strength of the half of the side. Therefore, the width of the side portion 2as in the thickness direction (Z-axis direction) of the polarizer 2 may be half or less of the thickness of the polarizing plate 2. The width of the side portion 2as in the thickness direction (Z-axis direction) of the polarizer 2 may be substantially the same as the spot diameter of the laser used for the measurement of Rq. The width of the side portion 2as in the thickness direction (Z-axis direction) of the polarizing plate 2 may be a width corresponding to the measurement limit using Rq of the laser microscope.

The first side S1 side of the protective film 3 is denser than the second side S2 side of the non-protective film 3, and it is easier to suppress the expansion or contraction of the polarizer 2 with temperature change by the protective film 3.

On the other hand, the side portion 2as on the second side S2 side of the non-protective film 3 is more likely to expand or contract as the temperature changes due to the side portion S1 on which the protective film 3 is adhered. Further, the larger the Rq of the side portion 2as on the second side S2 side of the non-protective film 3, the more the side portion 2as is unevenly deformed due to expansion or contraction with temperature change. In other words, the rougher the side portion 2as, the more easily the side portion 2as is deformed unevenly due to expansion or contraction with temperature changes. In particular, the side portion 2as is liable to be unevenly and sharply deformed due to rapid expansion or contraction with thermal shock. When the polarizer 2 is extended in one axial direction or two axial directions, the expansion or contraction of the polarizer 2 is anisotropic. Due to these factors, it is easy to cause cracking of the polarizer 2 with the side portion 2as as a starting point as the temperature of the polarizer 2 changes. In other words, it is easy to cause cracks in the end face 2a along the portion of the end face 2a that is not adjacent to the second side S2 of the protective film as the temperature of the polarizer 2 changes. For example, it is easy to cause cracking from the valley of the roughness curve (i.e., the deep recess of the side portion 2as) as a starting point. However, even in the case where the surface on the second side S2 side of the polarizer 2 is not laminated with the protective film, the Rq located on the side portion 2as on the second side S2 side of the non-protective film 3 can be easily reduced. The rupture of the polarizer 2 is easily suppressed as the temperature changes as a factor of the above-described rupture. In other words, when Rq of the side portion 2as on the second side S2 side of the non-protective film 3 is small, it is easy to suppress the occurrence of cracking of the side portion 2as on the side of the second side S2. For example, when the root mean square roughness Rq is 0.03 to 0.15 μm, it is easy to suppress the occurrence of cracking of the side portion 2as on the side of the second side S2. When the end faces of the polarizer or the polarizing plate are not polished, the end faces of the polarizers are not thickened by polishing, so the root mean square roughness Rq is substantially zero, and it is not easy to cause cracks in the end faces of the polarizers. However, when the end faces of the polarizer or the polarizing plate are not polished, it is difficult to adjust the size of the polarizer or the polarizing plate to a desired value with high precision (for example, a range of tolerances of product specifications). Therefore, the accuracy of the size of the polarizer having a root mean square roughness Rq of less than 0.03 μm tends to be lower than the accuracy of the size of the polarizer having a root mean square roughness Rq of 0.03 μm or more.

The rectangular polarizer 2 has four end faces 2a. Among the plurality of end faces 2a of the polarizer 2, the root mean square roughness Rq of the side portions 2as of a part of the end faces 2a may be 0.03 to 0.15 μm. The root mean square roughness Rq of the side portions 2as of all the end faces 2a of the polarizing plate 2 may be 0.03 to 0.15 μm. The more the end face 2a having the side portion 2as of Rq of 0.03 to 0.15 μm, the more easily it is suppressed from being cracked on the second side S2 side of the polarizing plate 2.

The resin constituting the polarizer 2 may be, for example, a polyvinyl alcohol resin, a polyvinyl acetate resin, an ethylene/vinyl acetate copolymer resin (EVA) resin, a polyamide resin or a polyester resin. The polarizer 2 may extend in one axial direction or two axial directions. The polarizer 2 can be dyed with iodine or a dichroic dye. The dyed polarizer 2 can be treated with boric acid. The polarizer 2 may also be one in which iodine is adsorbed on the polyvinyl alcohol film.

The thickness of the polarizing plate 2 can be, for example, 2 to 30 μm, 2 to 15 μm, or 2 to 10 μm. In general, the thinner the thickness of the polarizer, the easier it is to cause cracking of the polarizer. However, in the polarizing plate 1 including the polarizing plate 2 of the present embodiment, even when the thickness of the polarizing plate 2 is 10 μm or less, the crack of the polarizing plate 2 can be satisfactorily suppressed.

The protective film 3 may be, for example, a cellulose resin (such as triacetin cellulose), a polyolefin resin (such as a polypropylene resin), a cyclic olefin resin (such as a decene-based resin), or an acrylic resin (for example). Polymethyl methacrylate resin or the like or polyester resin (polyethylene terephthalate resin or the like).

The protective film 3 may have a thickness of 5 to 90 μm, 5 to 80 μm, or 5 to 50 μm.

The protective film 3 can be attached to the surface of the polarizer 2 via an adhesive layer. The solution constituting the resin of the protective film 3 may be applied onto the polarizer 2 to form a coating film, and the coating film may be dried to form a protective film directly on the surface of the polarizing film 2.

The resin constituting the adhesive layer may be, for example, an epoxy resin. The epoxy resin may be, for example, a hydrogenated epoxy resin, an alicyclic epoxy resin or an aliphatic epoxy resin. A polymerization initiator (photocationic polymerization initiator, thermal cationic polymerization initiator, photoradical polymerization initiator or thermal radical polymerization initiator, etc.) or other additives may be added to the epoxy resin (sensitization) Agent, etc.). The resin constituting the adhesive layer may be, for example, an acrylic resin such as acrylamide, acrylate, urethane acrylate or epoxy acrylate. A water-based adhesive containing a polyvinyl alcohol-based resin may also be used as the adhesive layer.

The resin constituting the pressure-sensitive adhesive layer 5 may be, for example, an acrylic resin, a polyoxymethylene resin, a polyester, a polyurethane, or a polyether. A solution containing the resin and any optional component may be applied to the surface of the polarizer 2 to form a coating film, and the coating film may be dried to form the pressure-sensitive adhesive layer 5.

The thickness of the pressure-sensitive adhesive layer 5 may be, for example, 2 to 500 μm, 2 to 200 μm, or 2 to 50 μm.

The pressure-sensitive adhesive layer 5 formed on a separator may be transferred onto the surface of the polarizer 2. The separator is attached to the other optical film of the polarizer 2 for the purpose of protecting the pressure-sensitive adhesive layer or preventing foreign matter from adhering. The separator is a peelable film. For example, when the polarizing plate 1 is attached to an image display element, the separator is peeled off to expose the pressure-sensitive adhesive layer. The separator is temporarily used in the manufacturing process of the polarizing plate 1, and then peeled off from the polarizing plate 1. The resin constituting the separator may be, for example, a polyethylene resin, a polypropylene resin, or a polyester resin (polyethylene terephthalate or the like).

The thickness of the separator may be, for example, 2 to 500 μm, 2 to 200 μm, or 2 to 100 μm.

The reflective polarizer 4 (second optical film) may be, for example, a multilayer film made of polycarbonate or the like. The thickness of the reflective polarizer 4 can be, for example, 15 to 200 μm.

The thickness of the entire polarizing plate 1 may be, for example, 10 to 500 μm, 10 to 300 μm, or 10 to 200 μm.

 [Cutting of the end of the polarizing plate]  

The average height Rc of the thickness curve elements of the end faces 2a of the polarizer 2 included in the polarizing plate 1 can be adjusted to be in the range of 0.05 to 1.7 μm by the cutting process of the end portions of the polarizing plate 1 described below. Moreover, the root mean square roughness Rq of the side portion 2as of the end surface 2a of the polarizing plate 2 included in the polarizing plate 1 can be adjusted to be in the range of 0.03 to 0.15 μm by the cutting processing described below. The cutting process will be described in detail below with reference to Figs. 2 to 5 .

First, a plurality of polarizing plates 1A having the same laminated structure as that of the polarizing plate 1 of the present embodiment are produced. Each of the polarizing plates 1A is the same as the polarizing plate 1 of the present embodiment except that the end faces thereof are not cut. The end surface 2a of the unpolarized polarizing plate 1A is not roughened, so that the Rc of the end surface 2a of the polarizing plate 2 of each of the polarizing plates 1A is less than 0.05. Further, the Rq of the side portion 2as of the end face 2a of each of the unpolarized polarizing plates 1A is less than 0.03. As shown in FIGS. 4 and 5, a plurality of polarizing plates 1A are stacked to form a laminated body 100. The size of each of the polarizing plates 1A is completely the same, and the entire surface of each of the polarizing plates 1A in the laminated body 100 is completely overlapped with each other. The end surface 100a of the laminated body 100 shown in FIG. 4 is a surface including the end surface of the polarizing plate 2. In other words, the end faces of the polarizers 2 included in the respective polarizing plates 1A are collected in the end faces 100a of the laminated body 100. As shown in Fig. 4, the end surface 100a of the laminated body 100 (in other words, the end surface of the polarizer 2) faces the cutting surface S of the cutting tool 10 and comes into contact with the cutting edge on the cutting surface S. For the convenience of illustration, the laminated body 100 is composed of four polarizing plates 1A, but the number of the polarizing plates 1A constituting the laminated body 100 is not particularly limited.

As shown in Fig. 2, the cutting tool 10 is fixed to a support 10a (cutter arbor). The cutting tool 10 is rotated against the rotation axis A. The number of rotations (rotation speed) of the cutting tool 10 is adjustable. Further, as shown in FIGS. 2 to 5, the cutting tool 10 has a disk shape. The rotation axis A of the cutting tool 10 is perpendicular to the end surface 100a of the laminated body 100 to be cut (in other words, the end faces of the respective polarizers 2). When the time in which the laminated body 100 is moved by 1 mm in the horizontal direction is set as the unit time, the number of rotations of the cutting tool 10 per unit time affects the average height Rc of the thickness curve elements of the end face 2a of the polarizing plate 2. Moreover, the number of rotations of the cutting tool 10 per unit time also affects the root mean square roughness Rq of the side portion 2as of the end surface 2a of the polarizing plate 2. The number of rotations of the cutting tool 10 per unit time may be, for example, 3.5 to 14 times or 5.6 to 10.2 times. When the number of rotations of the cutting tool 10 is within these ranges, the average height Rc of the thickness curve elements of the end faces 2a of the polarizer 2 is easily adjusted to 0.05 to 1.7 μm. Further, when the number of rotations of the cutting tool 10 is within the above range, the root mean square roughness Rq of the side portion 2as of the end surface 2a of the polarizing plate 2 is easily adjusted to 0.03 to 0.15.

The cutting tool 10 has a cutting surface S that is perpendicular to the rotation axis A. Therefore, the cutting surface S is parallel to the end surface 100a of the laminated body 100 to be cut. In other words, the cutting surface S is parallel to the end surface 2a of the polarizer 2 to be cut. As shown in FIGS. 2 and 3, the cutting surface S is provided with a first cutting portion group including the cutting portions 11a, 11b, and 11c, and a second cutting portion group including the cutting portions 11d, 11e, and 11f. Each cutting portion has a cutting edge B for cutting an end surface. Each of the cutting portions is disposed at substantially equal intervals around the rotation axis A. Each of the cutting portions protrudes from the cutting surface S toward the end surface 100a of the laminated body 100 to be cut. The cutting edge B is disposed on the protruding top surface of each of the cutting portions. The cutting edge B of each cutting portion is disposed so as to be parallel to the cutting surface S and extend. In other words, the cutting edges B of the respective cutting portions are arranged to extend parallel to the end faces 2a of the respective polarizers 2 in the laminated body 100. In addition, for the convenience of illustration, in FIGS. 4 and 5, each cutting portion provided on the cutting surface S of the cutting tool 10 is omitted, but the cutting tool 10 shown in FIGS. 2 to 5 is completely For the same person.

When the cutting tool 10 is rotated in the rotation direction (the arrow direction in FIGS. 2 to 5), the cutting portions 11a, 11b, and 11c are in contact with the end surface 100a of the laminated body 100 in this order, and the end surface 100a is cut (each End face 2a) of the polarizer 2. The distance from the cutting surface S to the cutting edge B of the cutting portion 11a is smaller than the distance from the cutting surface S to the cutting edge B of the cutting portion 11b. The distance from the cutting surface S to the cutting edge B of the cutting portion 11b is smaller than the distance from the cutting surface S to the cutting edge B of the cutting portion 11c. That is, the protruding height of the cutting edge B of the cutting portion 11b is higher than the protruding height of the cutting edge B of the cutting portion 11a, and the protruding height of the cutting edge B of the cutting portion 11c is higher than the protruding height of the cutting edge B of the cutting portion 11b. higher.

When the cutting tool 10 is rotated in the rotational direction, the cutting portions 11d, 11e, and 11f are in contact with the end surface 100a of the laminated body 100 in this order, and the end surface 100a (the end surface 2a of each polarizing plate 2) is cut. The distance from the cutting surface S to the cutting edge B of the cutting portion 11d is smaller than the distance from the cutting surface S to the cutting edge B of the cutting portion 11e. The distance from the cutting surface S to the cutting edge B of the cutting portion 11e is smaller than the distance from the cutting surface S to the cutting edge B of the cutting portion 11f. That is, the protruding height of the cutting edge B of the cutting portion 11e is higher than the protruding height of the cutting edge B of the cutting portion 11d, and the protruding height of the cutting edge B of the cutting portion 11f is higher than the protruding height of the cutting edge B of the cutting portion 11e. higher.

As shown in Fig. 3, the distance from the rotation axis A to the cutting edge B of the cutting portion 11b is shorter than the distance from the rotation axis A to the cutting edge B of the cutting portion 11a. The distance from the rotation axis A to the cutting edge B of the cutting portion 11c is shorter than the distance from the rotation axis A to the cutting edge B of the cutting portion 11b. The distance from the rotation axis A to the cutting edge B of the cutting portion 11e is shorter than the distance from the rotation axis A to the cutting edge B of the cutting portion 11d. The distance from the rotation axis A to the cutting edge B of the cutting portion 11f is shorter than the distance from the cutting edge B of the cutting portion 11e.

The cutting portions 11a, 11b, 11d, and 11e are used for roughing, and the cutting edges B are made of, for example, polycrystalline diamond. Among the cutting portion groups, the cutting portions 11c and 11f at the rearmost end are used for perfect machining, and the cutting edges B are formed of, for example, single crystal diamond. However, the material of each cutting edge B is not limited.

The circle drawn by the rotation of the cutting tool 10 in each cutting portion preferably intersects the surface of each of the polarizers 2 in the laminated body 100 (the surface of each of the polarizers 2 in the Z-axis direction) almost perpendicularly. For example, the circle drawn by each of the cutting edges B of the cutting portions 11c and 11f having the shortest distance from the rotation axis A preferably intersects the surface of each of the polarizers 2 in the laminated body 100 almost perpendicularly. In other words, as shown in Fig. 5, the entry angle θ of each of the cutting edges B with respect to the surface of each of the polarizers 2 is preferably as close as 90°. In other words, the entry angle θ of each of the cutting edges B with respect to the surface of the laminated body 100 facing the Z-axis direction is preferably as close as 90°. For example, the entry angle θ of each of the cutting edges B of the cutting portions 11c and 11f having the shortest distance from the rotation axis A is preferably closer to 90°. In order to bring the entry angle θ close to 90°, the diameter of the cutting face S of the cutting tool 10 is preferably larger than the thickness of the laminated body 100. Further, the diameter of the cutting surface S of the cutting tool 10 is preferably a size sufficient to uniformly cut the respective end faces of all of the stacked polarizing plates 1A. As shown in FIGS. 4 and 5, the height of the laminated body 100 is preferably substantially the same as the height of the axis of rotation A of the cutting tool 10. In other words, the position of the layered body 100 parallel to the direction (Z-axis direction) of the end faces 2a of the respective polarizers 2 is preferably substantially the same as the position of the axis of rotation A of the cutting tool 10 in the same direction. In other words, the position of the laminated body 100 parallel to the direction of the end surface 100a of the laminated body 100 is preferably substantially the same as the position of the rotational axis A of the cutting tool 10 in the same direction. The thickness of the laminated body 100 may be adjusted for the purpose of adjusting the entry angle θ of the cutting edge B. In other words, the number of the polarizing plates 1A constituting the laminated body 100 can be adjusted for the purpose of adjusting the entry angle θ of the cutting edge B. The smaller the thickness of the laminated body 100 is, the closer the entry angle θ of the cutting edge B is to 90° as compared with the diameter of the cutting tool 10. The thickness of the laminated body 100 may be adjusted for the purpose of adjusting the relative positional relationship between the laminated body 100 and the rotational axis A of the cutting tool 10. In other words, the number of the polarizing plates 1A constituting the laminated body 100 can be adjusted for the purpose of adjusting the relative positional relationship between the laminated body 100 and the rotational axis A of the cutting tool 10. As described above, the entry angle θ of each cutting edge B is adjusted to be substantially perpendicular, and the position of the laminated body 100 is aligned with the position of the rotation axis A of the cutting tool 10, and the number of rotations of the cutting tool 10 is appropriately adjusted. This makes it easy to adjust the average height Rc of the roughness curve elements of the end faces 2a of the polarizing plate 2 included in the polarizing plate 1 to be in the range of 0.05 to 1.7 μm. Further, the entry angle θ of each cutting edge B is adjusted to be substantially vertical, and the position of the laminated body 100 is aligned with the position of the rotation axis A of the cutting tool 10, and the number of rotations of the cutting tool 10 is appropriately adjusted, whereby it is easy to The root mean square roughness Rq of the side portion 2as of the polarizing plate 2 included in the polarizing plate 1 is controlled in the range of 0.03 to 0.15 μm. The number of rotations of the cutting tool 10 required to adjust Rc and Rq to the above-described ranges, respectively, can be grasped by preliminary experiments. In order to adjust the relative positional relationship between the laminated body 100 and the rotational axis A of the cutting tool 10, the cutting tool 10 can be moved in a direction parallel to the end surface 100a of the laminated body 100 (the end faces 2a of the polarizing plates 2). For example, the position of the cutting tool 10 can be adjusted freely in the Z-axis direction (up and down direction). At this time, the position of the laminated body 100 in the Z-axis direction can be fixed. The laminated body 100 is movably movable in a direction parallel to the end surface 100a of the laminated body 100 (the end surface 2a of each polarizing plate 2). For example, the position of the laminated body 100 in the Z-axis direction (for example, the up-and-down direction) can be adjusted freely. At this time, the position of the cutting tool 10 in the Z-axis direction may be fixed.

In each of the polarizing plates 1A constituting the laminated body 100, the polarizing plate 2 is preferably located above the protective film 3. Moreover, the elastic modulus of the protective film 3 is preferably higher than the elastic modulus of the polarizing plate 2. As shown in FIGS. 2 to 5, each cutting edge B of the cutting tool 10 is moved downward from the upper side of the laminated body 100. Therefore, when the polarizer 2 is located above the protective film 3, each of the cutting edges B comes into contact with the polarizer 2, and then comes into contact with the protective film 3. In other words, each of the cutting edges B enters the polarizer 2 having a low modulus of elasticity, and then enters the protective film 3 having a high modulus of elasticity. When the polarizer 2 and the protective film 3 are disposed in this manner, it is easy to adjust the average height Rc of the thickness curve elements of the end face 2a of the polarizer 2 in the range of 0.05 to 1.7 μm, and the side portion 2 of the polarizer 2 is easily removed. The root mean square roughness Rq is controlled in the range of 0.03 to 0.15 μm.

The rotating cutting tool 10 can be moved at a constant speed in a direction (Y direction) parallel to the end surface 100a of the laminated body 100. As the cutting tool 10 moves, the end faces 100a of the laminated body 100 (the end faces 2a of the respective polarizers 2) are gently cut. At this time, the position of the laminated body 100 can be fixed. The layered body 100 can also approach the cutting tool 10 at a constant speed in a direction (Y direction) parallel to the end surface 100a of the laminated body 100. As the laminated body 100 moves, the end surface 100a of the laminated body 100 (the end surface 2a of each polarizer 2) is gently cut. At this time, the position of the cutting tool 10 can be fixed.

According to the cutting method described above, the size of each of the polarizing plates 1A constituting the laminated body 100 can be adjusted with higher precision than the conventional cutting of the laminated body 100 by laser.

The above is a description of suitable embodiments of the present invention, but the present invention is not limited to the above embodiments.

For example, the polarizing plate may be provided with: a polarizer, a first optical film (for example, a protective film) laminated on the polarizer, a pressure-sensitive adhesive layer laminated on the first optical film, and a laminated pressure sensitive adhesive layer. A second optical film (eg, a reflective polarizer).

The first optical film or the second optical film may also be: a film with anti-glare function, a film with anti-surface reflection function, a reflective film, a semi-transmissive reflective film, a viewing angle compensation film, a release film, an optical compensation layer, and a touch Control the sensing layer, antistatic layer or antifouling layer. Of course, the first optical film may also be a reflective polarizer, and the second optical film may also be a protective film.

 [Examples]  

The examples and comparative examples are enumerated below to further specifically describe the contents of the present invention. Further, the present invention is not limited to the following embodiments.

 [Example 1]    (1) Production of polarizer  

A polyvinyl alcohol film having a thickness of 20 μm was prepared. The polyvinyl alcohol film had an average degree of polymerization of about 2,400 and a degree of saponification of 99.9 mol% or more.

The polyvinyl alcohol film was stretched about 4 times in one axis in a dry manner. The stretched state of the polyvinyl alcohol film caused by the stretching was maintained while the polyvinyl alcohol film was immersed in pure water at 40 ° C for 1 minute. Then, the polyvinyl alcohol film was immersed in the first staining solution (aqueous solution) for 60 seconds. The temperature of the first staining solution was adjusted to 28 °C. The mass ratio of iodine in the first staining solution: potassium iodide: water is 0.1:5:100. Then, the polyvinyl alcohol film was immersed in the second staining solution (aqueous solution) for 300 seconds. The temperature of the second staining solution was adjusted to 68 °C. The mass ratio of potassium iodide:boric acid:water in the second dyeing solution was 10.5:7.5:100. Then, the polyvinyl alcohol film was washed with pure water for 5 seconds. The temperature of the pure water was adjusted to 5 °C. The washed polyvinyl alcohol film was dried at 70 ° C for 180 seconds. By the above procedure, a polarizer of a strip film belonging to a long strip is obtained. The polarizer is oriented to adsorb iodine on a polyaxially stretched polyvinyl alcohol film. The thickness of the polarizer was 7 μm.

 (2) Modulation of water-based adhesives  

The polyvinyl alcohol powder was dissolved in hot water at 95 ° C to prepare an aqueous polyvinyl alcohol solution. The concentration of the polyvinyl alcohol in the aqueous solution was adjusted to 3% by mass. As the polyvinyl alcohol powder, "KL-318" manufactured by KURARAY Co., Ltd. was used. The polyvinyl alcohol powder had an average degree of polymerization of 1,800. The crosslinking agent was mixed with the polyvinyl alcohol aqueous solution to obtain a water-based adhesive. For the crosslinking agent, "Sumirez Resin 650" manufactured by Takaoka Chemical Industry Co., Ltd. was used. The mass of the crosslinking agent added to the aqueous polyvinyl alcohol solution was adjusted to be 1 part by mass based on 2 parts by mass of the polyvinyl alcohol powder.

 (3) Production of single-sided protective polarizer  

The polarizer described above is continuously conveyed in the longitudinal direction thereof. While the polarizer is being transported, the protective film is continuously fed from the reel body, and the protective film is transported while the protective film is subjected to corona treatment. The protective film was a ZEONOR film "ZF 14-023" manufactured by Zeon Co., Ltd., Japan. The thickness of the protective film was 23 μm. The polarizer and the protective film are transported, and the release film is continuously fed from the reel body, and the release film is transported. As the release film, a triacetyl cellulose film (TAC film) "KC8UX2MW" manufactured by Konica Minolta Co., Ltd. was used. The thickness of the release film was 80 μm. The release film was not subjected to saponification treatment.

Next, the water-based adhesive is interposed between the polarizer and the protective film so that pure water is interposed between the polarizer and the release film, and the layers are sandwiched by a pair of bonding rolls, whereby a laminated film is obtained. The laminated film system includes a polarizer, a water-based adhesive layer laminated on one surface of the polarizer, a protective film laminated on the aqueous adhesive layer, a pure water layer laminated on the other surface of the polarizer, and a laminate The release film in the pure water layer. The laminated film is conveyed to a drying device, and the aqueous adhesive layer is dried while volatilizing to remove the pure water layer. The temperature in the drying apparatus was adjusted to 80 °C. The drying time is 300 seconds. The peeling film was peeled off from the laminated body after drying to obtain a single-sided protective polarizing plate. The one-side protective polarizing plate is provided with a polarizing plate, a dried water-based adhesive layer laminated on one surface of the polarizer, and a protective film laminated on the aqueous adhesive layer.

 (4) Production of polarizing plate with brightness enhancement film  

On the surface of the polarizer provided on the one-side protective polarizing plate described above, a brightness enhancement film is bonded via a pressure-sensitive adhesive layer to obtain a polarizing plate with a brightness enhancement film. At the time of bonding, the orientation of each of the one-side protective polarizing plate and the brightness enhancing film is adjusted so that the extending direction of the polarizer is parallel to the extending axis of the brightness enhancing film. An acrylic resin is used for the pressure-sensitive adhesive layer. As the brightness enhancement film, "APF" of a reflective polarizer manufactured by 3M Co., Ltd. was used.

 (5) Production of polarizer with separator  

A film-shaped separator coated with a pressure-sensitive adhesive layer is prepared. An acrylic resin is used for the pressure-sensitive adhesive layer. The separator is attached to the surface of the brightness enhancement film provided on the polarizing plate with the brightness enhancement film via a pressure-sensitive adhesive layer to obtain a polarizing plate with a separator.

The polarizing plate with a separator includes a polarizer, a water-based adhesive layer laminated on one surface of the polarizer, a protective film (first optical film) laminated on the aqueous adhesive layer, and a superimposed on the polarizer. a first pressure-sensitive adhesive layer on the other surface, a brightness enhancement film (second optical film) laminated on the first pressure-sensitive adhesive layer, and a second pressure-sensitive adhesive layer laminated on the brightness enhancement film a separator laminated to the second pressure-sensitive adhesive layer.

 (6) Cutting processing  

The polarizing plate with the above-mentioned separator was cut into a size of 120 mm × 70 mm to obtain 100 polarizing plates. The cutting system uses Super Cutter. The structure, composition and size of the 100 polarizing plates are the same. The four sides of the 100 polarizing plates were aligned, and 100 polarizing plates were overlapped, thereby obtaining a laminated body. Hereinafter, for the convenience of explanation, the laminated body including 100 polarizing plates is regarded as the same as the laminated body 100 shown in FIGS. 4 and 5. The four end faces 100a of the laminated body 100 are cut using a cutting tool. The cutting process of the four end faces 100a is identical. The cutting tool used in the embodiment is the same as the cutting tool 10 shown in FIGS. 2 to 5 except that the first cutting portion group and the second cutting portion group each have five cutting portions. Hereinafter, for convenience of explanation, the cutting tool used in the embodiment is considered to be the same as the cutting tool 10 shown in FIGS. 2 to 5. Hereinafter, the Z-axis direction in each drawing is regarded as the upper direction, and the X-axis direction and the Y-axis direction are regarded as the horizontal direction. When the laminated body 100 is formed, 100 polarizing plates 1A are stacked so that the polarizing plate 2 is positioned on the protective film 3 in each polarizing plate 1A.

The five cutting edges B of the respective cutting portion groups are placed on the cutting surface S such that the protruding heights of the five cutting edges B gradually increase in a direction opposite to the direction of rotation of the cutting tool 10. Further, the distance from the rotation axis A to the cutting edge B of the cutting portion is gradually shortened in a direction opposite to the rotation direction of the cutting tool 10, and the five cutting portions of each cutting portion group are arranged. On the cutting surface S. A total of ten cutting portions constituting the first cutting portion group and the second cutting portion group are arranged at equal intervals so as to surround the rotation axis A. The height of the pair of cutting edges B is the same relative to each other across the rotation axis A. The distance between the cutting edge B of the cutting portion and the rotation axis A is the same across the rotation axis A. Since each cutting edge group of the cutting tool 10 has five cutting edges B having different heights, one rotation of the cutting tool 10 corresponds to cutting of five stages having different depths.

In the cutting process of the end surface 100a of the laminated body 100, a pair of cutting tools 10 are used. The cutting faces S of the pair of cutting tools 10 are opposed to each other. The interval between the pair of cutting tools 10 is adjusted so that the laminated body 100 can be accommodated between the pair of cutting tools 10. The orientation of the cutting tool 10 is adjusted such that the rotation axis A of the cutting tool 10 is horizontal. The position of each cutting tool 10 is fixed, and each cutting tool 10 is rotated about the rotation axis A. The orientation of the end surface 100a of the laminated body 100 is adjusted so that the end surface 100a of the laminated body 100 is perpendicular to the rotation axis A of the cutting tool 10 (the normal to the cutting surface S). Further, the orientation of the laminated body 100 is adjusted so that the surface of the laminated body 100 is horizontal.

A synthetic resin disk having the same thickness as the laminated body 100 and being smaller than the laminated body 100 is placed under the laminated body 100, and the height at which the laminated body 100 is placed is adjusted. As shown in FIGS. 4 and 5, by adjusting the height at which the laminated body 100 is disposed, the entry angle θ of each cutting edge B with respect to the surface of each polarizer 2 in the laminated body 100 is substantially perpendicular, and the laminated body 100 is The height of the arrangement is substantially the same as the height of the rotation axis A of the cutting tool 10. The thickness of the synthetic resin disk used for adjusting the height of the laminated body 100 was 60 mm.

In the cutting process, the height at which the laminated body 100 is placed is maintained constant. In the cutting process, the laminated body 100 is moved at a constant speed in the horizontal direction (Y-axis direction), and the laminated body 100 is gradually introduced between the pair of rotating cutting tools 10. In other words, one end surface 100a of the laminated body 100 is slowly cut by the cutting surface S of the cutting tool 10, and the other end surface 100a of the laminated body 100 is slowly cut by the cutting surface S of the other cutting tool 10. The laminated body 100 is continuously moved in the horizontal direction (Y-axis direction) until the entire end surface 100a of the laminated body 100 is cut.

In each of the polarizing plates 1, since the polarizer 2 is disposed on the protective film 3, in the primary rotation of the cutting tool 10, each cutting edge B of the cutting tool 10 first cuts the end faces of the polarizing plates 2 in the laminated body 100. Then, the end faces of the respective protective films 3 adjacent to the respective polarizers 2 are cut.

When the time in which the laminated body 100 was moved by 1 mm in the horizontal direction was regarded as the unit time, the number of rotations of the cutting tool 10 per unit time was adjusted to 10.2 times.

Through the above steps, 100 polarizing plates (polarizing plates of Example 1) were obtained.

 (7-1) Determination of the average height Rc of the roughness curve elements  

The average height Rc of the thickness curve elements of the end faces 2a of the polarizer 2 included in the polarizing plate 1 of Example 1 was measured by the following procedure. The end face 2a of the polarizer 2 to be measured is measured, and the end face of the cutting by the cutting tool 10 is performed. For the measurement of Rc, a 3D measuring laser microscope "OLS4100" manufactured by Olympus Co., Ltd. was used. Five polarizing plates 1 were randomly taken out from the 100 polarizing plates of Example 1. Rc of the two end faces 2a perpendicular to the extending axis direction of the polarizing plate 2 among the four end faces of the polarizing plate 2 included in one polarizing plate 1 was measured, and the average value of Rc of the two end faces 2a was calculated. The average value of Rc of each of the polarizing plates 2 included in the five polarizing plates 1 was calculated in the same manner, and the average values of the five Rc were further averaged. The Rc of Example 1 calculated by the above procedure was 0.07 μm.

 (7-2) Determination of root mean square roughness Rq  

The root mean square roughness Rq of the side portion 2as of the end surface 2a of the polarizing plate 2 of the polarizing plate 1 of the first embodiment was measured by the following procedure. The end face 2a of the polarizer 2 to be measured is measured, and the end face of the cutting by the cutting tool 10 is performed. For the measurement of Rq, a 3D measuring laser microscope "OLS4100" manufactured by Olympus Co., Ltd. was used. Five polarizing plates 1 were randomly taken out from the 100 polarizing plates of Example 1. Rq of the two end faces 2a perpendicular to the extending axis direction of the polarizing plate 2 among the four end faces of the polarizing plate 2 included in one polarizing plate 1 was measured, and the average value of Rq of the two end faces 2a was calculated. The average value of Rq of each of the polarizing plates 2 included in the five polarizing plates 1 was calculated in the same manner, and the average values of the five Rqs were further averaged. The Rq of Example 1 calculated by the above procedure was 0.031 μm.

 (8) Thermal shock test  

The thermal shock test was carried out using the one polarizing plate of Example 1 (polarizing plate after cutting) by the following procedure.

The separator was peeled off from the polarizing plate with the separator, and the polarizing plate was attached to the alkali-free glass plate via the adhesive layer to obtain a test sample. The alkali-free glass plate is "Eagle-XG" manufactured by Corning Incorporated. The sample was sealed in an autoclave for 20 minutes, and the sample was subjected to a pressure treatment. The temperature in the autoclave was maintained at 50 °C. The pressure in the autoclave was maintained at 5 MPa. The sample after the press treatment was allowed to stand for 1 day in a gas atmosphere having a temperature of 23 ° C and a relative humidity of 60%.

The sample subjected to the above steps was placed in a test tank of a thermal shock tester. Further, the cycle including the following steps 1 to 3 was repeated 12 times. The thermal shock tester used "TSA-301L-W" manufactured by ESPEC AG.

Step 1: A step of maintaining the temperature in the test tank at -40 ° C for 30 minutes.

Step 2: After the step 1, the temperature in the test tank was maintained at 23 ° C for 5 minutes.

Step 3: After the step 2, the temperature in the test tank was maintained at 85 ° C for 30 minutes.

After repeating the cycle 12 times, the sample was taken out from the test tank. Then, the end of the sample was observed with an optical microscope, and it was investigated whether or not the end face 2a of the polarizer 2 was broken. The optical microscope is "VHX-5000" manufactured by Keyence Corporation. The number of cracks per unit length of the end face 2a of the polarizer 2 was determined. "Unit length" means a line segment in the end face of the polarizer perpendicular to the thickness direction of the polarizer and having a length of 10 mm. The "number of cracks per unit length" means the number of cracks in which the end faces of the polarizer are staggered with the unit length. The number of ruptures of Example 1 was zero.

 (9) Evaluation of the accuracy of the size of the polarizing plate  

The length of one side of the polarizing plate of Example 1 was measured, and it was evaluated whether the measured value was within the tolerance of the target value ± 50 μm. The measured value of the length of one side of the polarizing plate of Example 1 was within the range of the tolerance of the target value ± 50 μm. In other words, it was confirmed that the accuracy of the size of the polarizing plate of Example 1 was high.

 [Examples 2 to 9]  

In the second to ninth embodiments, the number of rotations of the cutting tool 10 per unit time was adjusted to the values shown in Table 1 below. In the cutting processes of Examples 5 to 7 and 9, the synthetic resin disk was not disposed under the laminated body 100. In other words, in each of the cutting processes of Examples 5 to 7 and 9, the height of the laminated body 100 is lower than that of the first embodiment. Therefore, in the cutting processes of each of the fifth to seventh embodiments, the entry angle θ of each of the cutting edges B with respect to the surface of each of the polarizers 2 in the laminated body 100 is not perpendicular. Further, in the cutting processes of each of the fifth to seventh embodiments, the height of the laminated body 100 is not substantially the same as the height of the rotation axis A of the cutting tool 10.

Each of the polarizing plates of Examples 2 to 9 was produced in the same manner as in Example 1 except for the above matters concerning the cutting process. Rc and Rq of each of Examples 2 to 9 were measured in the same manner as in Example 1. Rc and Rq of each of Examples 2 to 9 are shown in Table 1 below. The number of cracks of each of Examples 2 to 9 was measured in the same manner as in Example 1. When a crack is formed on the end face of the polarizer, the length of the crack is also measured. The length of the rupture refers to the distance from the end of the rupture of the end face of the polarizer to the end of the other rupture. The number of ruptures and the length of rupture of each of Examples 2 to 9 are shown in Table 1 below. The length of the crack shown in Table 1 is the length of the longest crack among the cracks formed by the end faces of the respective polarizers. The dimensional accuracy of each of the polarizing plates of Examples 2 to 9 was evaluated in the same manner as in Example 1. The dimensional accuracy of each of the polarizing plates of Examples 2 to 9 is shown in Table 1 below.

 [Comparative Example 1]  

In the cutting process of Comparative Example 1, the synthetic resin disk was not disposed under the laminated body 100. In other words, in the cutting process of Comparative Example 1, the height of the laminated body 100 is lower than that of the first embodiment. Therefore, in the cutting process of Comparative Example 1, the entry angle θ of each cutting edge B with respect to the surface of each polarizer 2 in the laminated body 100 is not perpendicular. Further, in the cutting process of Comparative Example 1, the height at which the laminated body 100 is disposed is not substantially the same as the height of the rotation axis A of the cutting tool 10. Further, in the cutting process of Comparative Example 1, the number of rotations of the cutting tool 10 per unit time was adjusted to the values shown in Table 1 below.

A polarizing plate of Comparative Example 1 was produced in the same manner as in Example 1 except for the above matters concerning the cutting process. Rc and Rq of Comparative Example 1 were measured in the same manner as in Example 1. Rc and Rq of Comparative Example 1 are shown in Table 1 below. The number of cracks and the length of the crack of Comparative Example 1 were measured in the same manner as in Examples 1 to 9. The number of cracks and the length of the crack of Comparative Example 1 are shown in Table 1 below. The dimensional accuracy of the polarizing plate of Comparative Example 1 was evaluated in the same manner as in Example 1. The dimensional accuracy of the polarizing plate of Comparative Example 1 is shown in Table 1 below.

 [Comparative Example 2]  

A polarizing plate of Comparative Example 2 was produced in the same manner as in Example 1 except that the cutting was not performed. Rc and Rq of Comparative Example 2 were measured in the same manner as in Example 1. Rc and Rq of Comparative Example 2 are shown in Table 1 below. The number of cracks of Comparative Example 2 was measured in the same manner as in Example 1.

The number of cracks of Comparative Example 2 is shown in Table 1 below. The dimensional accuracy of the polarizing plate of Comparative Example 2 was evaluated in the same manner as in Example 1. The measured value of the length of one side of the polarizing plate of Comparative Example 2 was outside the range of the tolerance of the target value of ±50 μm. In other words, it was confirmed that the accuracy of the size of the polarizing plate of Comparative Example 2 was low.

 [Industrial Applicability]  

The polarizing plate of the present invention can be applied to, for example, an optical component constituting an image display device such as a liquid crystal television, an organic EL television, or a smart phone attached to a liquid crystal cell or an organic EL device.

Claims (5)

 A polarizer is a film-shaped polarizer, and an average height Rc of the thickness curve elements of the end faces of the polarizer is 0.05 to 1.7 μm.    A polarizing plate comprising the polarizer described in claim 1 and a first optical film superposed on a surface of the polarizer.    The polarizing plate of claim 2, wherein a first side of the side of one end surface of the polarizer is adjacent to the first optical film, and the first side of the end face is enclosed The two sides are located on opposite sides of the first side, and the root mean square roughness Rq of the portion along the second side of the end faces is 0.03 to 0.15 μm.    The polarizing plate according to claim 2 or 3, further comprising an adhesive layer laminated on the other surface of the polarizer and a second optical film laminated on the adhesive layer.    An image display device comprising the polarizing plate according to any one of claims 2 to 4.