TWI728194B - 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 μm.

Description

Polarizer, polarizer and image display device

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

In recent years, there has been a demand for thinning of image display devices including liquid crystal cells, organic EL elements, and the like.

Therefore, the polarizer used in the image display device is also formed into a thin film shape. Since the film-like polarizer is brittle and easy to crack, in order to protect the polarizer, a protective film is attached to both sides of the polarizer when the polarizer is manufactured. Moreover, in order to improve the dimensional accuracy of the polarizing plate when manufacturing a polarizing plate, the end of a laminate composed of a protective film, a polarizer, and the like is polished (for example, refer to Patent Document 1).

[Prior technical literature] 〔Patent Documents〕

[Patent Document 1] Japanese Patent No. 3875331

In recent years, in order to make the polarizing plate thinner, the development of a polarizing plate with a protective film attached to only one side of the polarizer has been developed. However, a polarizer with a protective film laminated on only one side is easier to crack (crack) than a polarizer with a protective film laminated on both sides. Such cracks are caused by the expansion or contraction of the polarizer that changes with temperature. In particular, it is understood that the polarizer is liable to crack due to a rapid temperature change (thermal shock) of the polarizer.

Moreover, in recent years, in order to improve the design, the frame of the image display device is required to be narrow. In response to this requirement, high dimensional accuracy is also required for the end of the polarizing plate. In order to adjust the size of the polarizing plate with high accuracy, it is necessary to cut (grind) the end portion of the laminate composed of a protective film and a polarizer with high accuracy. However, a polarizer with a protective film laminated on only one side is more likely to burden the end face of the polarizer during cutting than a polarizer laminated with a protective film on both sides, and the end face of the polarizer tends to become rough. The thickness of the end face is likely to cause cracking of the polarizer with temperature changes. In particular, it is understood that the end surface of the polarizer on the surface side without the protective film is more likely to be cracked than the end surface of the polarizer on the surface side of the laminated protective film.

The present invention is made in view of the above situation, and aims to provide a polarizer with high dimensional accuracy and not easily cracked with temperature changes, a polarizer provided with the polarizer, and an image display device including the polarizer.

One aspect of the polarizer of the present invention is a film-like polarizer, and the average height Rc of the roughness curve element of the end surface of the polarizer is 0.05 to 1.7 μm. The average height Rc may also be 0.05 to 0.28 μm.

One aspect of the polarizing plate of the present invention is provided with the above-mentioned polarizer and the first optical film laminated on one surface of the polarizer.

In one aspect of the present invention, the first side among the sides surrounding an end surface of the polarizer is adjacent to the first optical film, and the second side among the sides surrounding the end surface is located on the opposite side of the first side. , The root mean square thickness Rq of the part along the second side of the end surface can be 0.03 to 0.15 μm.

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

The polarizing plate of one aspect of the present 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 of one aspect of the present 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 present invention, the second optical film may also be a reflective polarizer.

An image display device of one aspect of the present invention includes the above-mentioned polarizing plate.

According to the present invention, it is possible to provide a polarizer with high dimensional accuracy and not easily cracked with temperature changes, a polarizer provided with the polarizer, and an image display device including the polarizer.

1‧‧‧Polarizer

2‧‧‧Film-like polarizer

2a‧‧‧The end face of the polarizer

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

3‧‧‧Protection film (the first optical film)

4‧‧‧Reflective polarizer (second optical film)

5‧‧‧Pressure-sensitive adhesive layer

10‧‧‧Cutting Tools

10a‧‧‧Support

100‧‧‧Layered body

100a‧‧‧end face

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

1A‧‧‧Polarizer

A‧‧‧Rotation axis

B‧‧‧Cutting edge

S‧‧‧cutting surface

S1‧‧‧First side

S2‧‧‧Second side

S3‧‧‧The third side

S4‧‧‧The fourth side

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

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

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

Fig. 4 is a schematic diagram showing the positions of the cutting tool shown in Fig. 2 and a laminate composed of a plurality of polarizing plates.

Fig. 5 is a schematic diagram showing the positions of the cutting tool shown in Fig. 3 and a laminate composed of a plurality of polarizing plates.

The following describes suitable embodiments of the present invention with reference to the drawings. In the diagrams, the same components are marked with the same symbols. The present invention is not limited to the following embodiments. X, Y, and Z shown in each figure mean three coordinate axes that intersect each other perpendicularly. The directions indicated by each coordinate axis are common in all the figures. The size and the size ratio seen in the figure may not be consistent with the actual one.

[Polarizer, Polarizer and Image Display Device]

As shown in (a) in Figure 1, the polarizing plate 1 of this embodiment includes: a film-like polarizer 2, a first optical film (3) laminated on one surface of the polarizer 2, and a first optical film (3) laminated on one surface of the polarizer 2. The pressure-sensitive adhesive layer 5 on the other surface of the polarizer 2 and the second optical film (4) laminated on the pressure-sensitive adhesive layer 5. The first optical film system is, for example, the protective film 3. The second optical film system is, for example, a reflective polarizer 4. The polarizer 2 and the optical film and layer of the polarizer 1 may all be transparent. In the polarizing plate 1 of this embodiment, only on one side of the polarizer 2, the optical film (first optical film) is directly adhered to the polarizer 2 through an adhesive layer, not through a pressure-sensitive adhesive layer.

The polarizer 2, the first optical film (3), the pressure-sensitive adhesive layer 5, and the second optical film (4) are all rectangles with approximately the same size. The entire polarizing plate 1 is also a rectangular film. However, the shapes of the polarizing plate 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, so they are not limited. The shape of each of the polarizer 2 and the polarizer 1 may be polygonal, circular, or elliptical, for example. Part or all of the outline of each of the polarizer 2 and the polarizer 1 may be a straight line or a curved line.

The image display device of this embodiment may be a liquid crystal display device or an organic EL display device, for example. The liquid crystal display device may include, for example, a liquid crystal cell, and a polarizing plate 1 attached to one 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, usually two polarizing plates can be arranged. The polarizer provided on the polarizer arranged on the back side of the liquid crystal cell is easier to be exposed to heat than the polarizer provided on the polarizer arranged on the visible side of the liquid crystal cell. Therefore, if the polarizing plate 1 provided with the polarizing film 2 of this embodiment is arrange|positioned on the back side of a liquid crystal cell, the cracking of the polarizing plate 2 with temperature change can be suppressed. The reason will be described later.

The average height Rc of the roughness curve elements of the end surface 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 roughness curve element of the end surface 2a may also be defined by the following formula 1, for example.

In Formula 1, Rc is the average of the height Zt of the roughness curve element (contour curve element) 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 contour curve 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 value) and valley (minimum value). Rc can be measured on the end surface 2a of the polarizer 2 with a laser microscope, for example.

The larger the average height Rc of the roughness curve element of the end face 2a, in other words, the rougher the end face 2a, the more the end face 2a will deform unevenly due to expansion or contraction due to temperature changes. In particular, the end surface 2a may deform unevenly and rapidly due to abrupt expansion or contraction due to thermal shock. When the polarizer 2 extends in the uniaxial direction or the biaxial direction, 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 cracks in the polarizer 2 from the end surface 2a as a starting point. For example, the valley of the contour curve element (that is, the deep recess of the end surface 2a) is used as the starting point to cause cracking. However, in this embodiment, the average height Rc of the roughness curve elements of the end surface 2a is 0.05 to 1.7 µm. Therefore, the various cracking factors described above can be reduced, and the polarizer 2 can be prevented from cracking due to temperature changes. The length of the rupture formed at the end face 2a with an average height Rc of 0.05 to 1.7 μm tends to be shorter than the length of the rupture formed at the end face 2a with an average height Rc greater 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 element of the end surface 2a of the polarizer 2 is almost uniform throughout the entire range of the end surface 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 roughness curve element of the end surface 2a of the polarizer 2 increases as it moves away from the interface between the polarizer 2 and the protective film ( Surface) and the tendency to become larger. Since the polarizer 2 is a stretched film, it is prone to cracks, and in particular, the end surface of the polarizer on the surface side without a protective film is likely to be roughened by the polishing blade treatment. Therefore, the average height Rc of the roughness curve element of the end surface 2a of the polarizer 2 tends to become larger as it moves away from the interface between the polarizer 2 and the protective film. When the average height Rc of the roughness curve elements of the end face 2a of the polarizer 2 is not uniform, the maximum value of the average height Rc of the roughness curve elements measured on the end face 2a of the polarizer 2 may be, for example, 0.05 to 0.28 μm. When the average height Rc of the roughness curve element of the end face 2a of the polarizer 2 is not uniform, the length of the fracture formed by the end face 2a whose maximum average height Rc is 0.05 to 0.28 μm is greater than the average height Rc The length of the fracture formed by the end face 2a with a value greater than 0.28 μm tends to be shorter. In addition, when the average height Rc of the roughness curve element of the end face 2a of the polarizer 2 is not uniform, the number of cracks formed at the end face 2a where the maximum value of the average height Rc is 0.05 to 0.28 μm is higher than the average height Rc The maximum value is greater than 0.28 μm, and the number of cracks formed by the end face 2a tends to be smaller.

When the end face of the polarizer or the polarizing plate is not polished, the end face of the polarizer will not become rough due to grinding, so the average height Rc of the end face of the polarizer is approximately zero, and the end face of the polarizer is unlikely to be cracked. In other words, the smaller the average height Rc of the end surface 2a, the less likely it is that the end surface of the polarizer is cracked. However, when the polarizer or the end face of the polarizer is not polished, it is difficult to adjust the size of the polarizer or the polarizer to a desired value with high accuracy (for example, the tolerance range of the product specification). Therefore, the dimensional accuracy of the polarizer whose average height Rc of the end face 2a is less than 0.05 μm is worse than that of the polarizer whose average height Rc of the end face 2a is 0.05 μm or more. In other words, the dimensional accuracy of a polarizer with a polished end surface is higher than that of a polarizer with an unpolished end surface.

The rectangular polarizer 2 has four end surfaces 2a. The average height Rc of the roughness curve elements of some of the end surfaces 2a of the polarizer 2 can be set to 0.05 to 1.7 μm. The average height Rc of the roughness curve elements of all the end faces 2a of the polarizer 2 may be set to 0.05 to 1.7 μm. The more end faces 2a with Rc of 0.05 to 1.7 μm, the easier it is to suppress the occurrence of cracks in the polarizer 2.

As shown in (b) in Figure 1, one end surface 2a of the polarizer 2 is surrounded by the first side S1, the second side S2, the third side S3, and the fourth side S4. In other words, the periphery of the end surface 2a is formed by 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 surrounding the end surface 2a is adjacent to the protective film 3 (first optical film). The second side S2 among the four sides surrounding the end surface 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 the side not adjacent to the protective film 3.

The root mean square thickness Rq of the portion (2as) of the end surface 2a along the second side S2 may be 0.03 to 0.50 μm. Hereinafter, the part along the second side S2 of the end surface 2a may be 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 thickness Rq of the side portion 2as of the end surface 2a can be defined by the following formula 2, for example.

In Formula 2, 1 (lowercase L of the English letter) is the reference length of the side portion 2as of the end surface 2a. Z(x) is the height of the thickness curve at any position x on the reference length 1. Rq can be obtained, for example, by measuring a laser microscope on the side 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 may be narrow as long as Rq can be measured. If the end face 2a of the polarizer 2 is equally divided into two regions by the middle (center) of the first side S1 and the second side S2, Rq can be said to indicate the second side S2 without the protective film 3 in the two regions An index of the mechanical strength of 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 polarizer 2. The width of the side portion 2as in the thickness direction (Z-axis direction) of the polarizer 2 may be approximately 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 polarizer 2 may also be a width equivalent to the measurement limit of Rq using a laser microscope.

Compared with the second side S2 side without the protective film 3, the protective film 3 is easier to suppress the expansion or contraction of the polarizer 2 with temperature changes on the first side S1 side where the protective film 3 is closely adhered.

In contrast, the side portion 2as located on the second side S2 side without the protective film 3 is easier to expand or contract with temperature changes than the first side S1 side with the protective film 3 attached. In addition, the larger the Rq of the side portion 2as located on the second side S2 side of the non-protective film 3, the more the side portion 2as will deform unevenly due to expansion or contraction with temperature changes. In other words, the rougher the side portion 2as, the easier it is to deform the side portion 2as unevenly due to expansion or contraction with temperature changes. In particular, the side portion 2as is likely to deform unevenly and sharply due to rapid expansion or contraction due to thermal shock. When the polarizer 2 extends in the uniaxial direction or the biaxial direction, the expansion or contraction of the polarizer 2 is anisotropic. Due to these factors, it is easy to cause cracks in the polarizer 2 with the side portion 2as as the starting point as the temperature of the polarizer 2 changes. In other words, as the temperature of the polarizer 2 changes, cracks are likely to occur in the end surface 2a along the portion not adjacent to the second side S2 of the protective film. For example, it is easy to cause cracks by starting from the valley of the thickness curve (that is, the deep depression of the side portion 2as). However, even if the protective film is not laminated on the surface of the polarizer 2 on the second side S2 side, by reducing the Rq of the side portion 2as on the second side S2 side without the protective film 3, it can be easily reduced The above-mentioned factors of breakage can easily suppress the breakage of the polarizer 2 due to temperature changes. In other words, if the Rq of the side portion 2as located on the second side S2 side without the protective film 3 is small, it is easy to suppress the occurrence of cracks in the side portion 2as located on the second side S2 side. For example, when the root mean square thickness Rq is 0.03 to 0.15 μm, it is easy to suppress the occurrence of cracks in the side portion 2as located on the second side S2 side. When the end face of the polarizer or the polarizing plate is not polished, the end face of the polarizer will not become thick due to grinding, so the root mean square roughness Rq is approximately zero, and the end face of the polarizer is unlikely to be cracked. However, when the polarizer or the end face of the polarizer is not polished, it is difficult to adjust the size of the polarizer or the polarizer to a desired value with high accuracy (for example, the tolerance range of the product specification). Therefore, the dimensional accuracy of the polarizer whose root-mean-square thickness Rq is less than 0.03 μm tends to be lower than that of the polarizer whose root-mean-square thickness Rq is 0.03 μm or more.

The rectangular polarizer 2 has four end surfaces 2a. The root mean square thickness Rq of the side portion 2as of some of the end surfaces 2a of the polarizer 2 can be set to 0.03 to 0.15 μm. The root mean square thickness Rq of the side portion 2as of all the end faces 2a of the polarizer 2 may be set to 0.03 to 0.15 μm. The more end faces 2a having side portions 2as with Rq of 0.03 to 0.15 μm, the easier it is to suppress the occurrence of cracks on the second side S2 side of the polarizer 2.

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

The thickness of the polarizer 2 may be, for example, 2 to 30 μm, 2 to 15 μm, or 2 to 10 μm. Generally speaking, the thinner the thickness of the polarizer, the more likely it is to break the polarizer. However, in the polarizing plate 1 provided with the polarizing plate 2 of this embodiment, even when the thickness of the polarizing plate 2 is 10 μm or less, the cracking of the polarizing plate 2 can be suppressed satisfactorily.

The protective film 3 may be, for example, cellulose resin (triacetyl cellulose, etc.), polyolefin resin (polypropylene resin, etc.), cyclic olefin resin (norbornene resin, etc.), acrylic resin ( Polymethyl methacrylate resin, etc.) or polyester resin (polyethylene terephthalate resin, etc.).

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

The protective film 3 can be bonded to the surface of the polarizer 2 via an adhesive layer. It is also possible to apply a solution of the resin constituting the protective film 3 on the polarizer 2 to form a coating film, and then dry the coating film, thereby directly forming a protective film on the surface of the polarizer 2.

The resin constituting the adhesive layer may be, for example, epoxy resin. The epoxy resin may be, for example, a hydrogenated epoxy resin, an alicyclic epoxy resin, or an aliphatic epoxy resin. It is also possible to add polymerization initiators (photocationic polymerization initiators, thermal cationic polymerization initiators, photoradical polymerization initiators or thermal radical polymerization initiators, etc.) or other additives (sensitizers) to the epoxy resin Agent, etc.). The resin constituting the adhesive layer may be, for example, acrylic resins such as acrylamide, acrylate, urethane acrylate, and epoxy acrylate. A water-based adhesive containing polyvinyl alcohol-based resin can also be used for the adhesive layer.

The resin constituting the pressure-sensitive adhesive layer 5 may be, for example, acrylic resin, silicone resin, polyester, polyurethane, or polyether. The solution containing these resins and any additional components can be coated on the surface of the polarizer 2 to form a coating film, and the coating film can be dried, thereby forming 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 the separator can also be transferred to the surface of the polarizer 2. The separator is attached to other optical films of the polarizer 2 for the purpose of protecting the pressure-sensitive adhesive layer or preventing the adhesion of foreign matter. 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 during the manufacturing process of the polarizing plate 1 and can be peeled off from the polarizing plate 1 afterwards. The resin constituting the separator may be, for example, polyethylene resin, polypropylene resin, or polyester resin (polyethylene terephthalate, etc.).

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 may be 15 to 200 μm, for example.

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〕

By cutting the end of the polarizing plate 1 described below, the average height Rc of the roughness curve elements of the end surface 2a of the polarizing plate 2 of the polarizing plate 1 can be controlled within the range of 0.05 to 1.7 µm. Furthermore, by the cutting process described below, the root mean square thickness Rq of the side portion 2as of the end surface 2a of the polarizer 2 of the polarizer 1 can be adjusted within the range of 0.03 to 0.15 μm. Hereinafter, the cutting process will be described in detail with reference to FIGS. 2 to 5.

First, a plurality of polarizing plates 1A having the same laminated structure as the polarizing plate 1 of the present embodiment is produced. Each polarizing plate 1A is the same as the polarizing plate 1 of this embodiment except that the end surface is not cut. The end surface 2a of the uncut polarizing plate 1A is not roughened, so the Rc of the end surface 2a of the polarizing plate 2 of each polarizing plate 1A is less than 0.05. Furthermore, the Rq of the side portion 2as of the end surface 2a of each polarizing plate 1A that is not cut is less than 0.03. As shown in FIGS. 4 and 5, a plurality of polarizing plates 1A are stacked to form a laminate 100. The dimensions of the polarizing plates 1A are completely the same, and the entire surfaces of the polarizing plates 1A in the laminate 100 are completely overlapped with each other. The end face 100a of the laminated body 100 shown in FIG. 4 is a face including the end face of the polarizer 2. In other words, in the end surface 100a of the laminated body 100, the end surface of the polarizer 2 provided in each polarizing plate 1A is gathered. As shown in FIG. 4, the end surface 100a of the laminated body 100 (in other words, the end surface of the polarizer 2) is opposed to the cutting surface S of the cutting tool 10, and is in contact with the cutting edge on the cutting surface S. For the convenience of the illustration, the laminated body 100 is composed of four polarizing plates 1A, but the number of 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 body 10a (cutter arbor, shaft). The cutting tool 10 rotates with respect to the rotation axis A. As shown in FIG. The number of rotations (rotation speed) of the cutting tool 10 can be adjusted freely. In addition, as shown in FIGS. 2 to 5, the cutting tool 10 has a disk shape. The rotation axis A of the cutting tool 10 perpendicularly intersects the end face 100a of the laminated body 100 to be cut (in other words, the end face of each polarizer 2). When the time for the laminated body 100 to move 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 roughness curve element of the end surface 2a of the polarizer 2. Moreover, the number of rotations of the cutting tool 10 per unit time also affects the root mean square thickness Rq of the side portion 2as of the end surface 2a of the polarizer 2. The number of rotations of the cutting tool 10 per unit time may be 3.5 to 14 times or 5.6 to 10.2 times, for example. When the number of rotations of the cutting tool 10 is within these ranges, it is easy to control the average height Rc of the roughness curve element of the end surface 2a of the polarizer 2 to 0.05 to 1.7 μm. Moreover, when the number of revolutions of the cutting tool 10 is within the above-mentioned range, it is easy to control the root mean square thickness Rq of the side portion 2as of the end surface 2a of the polarizer 2 to 0.03 to 0.15.

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

When the cutting tool 10 is rotated in the direction of rotation (the arrow direction in Figs. 2 to 5), the cutting portions 11a, 11b, and 11c abut the end face 100a of the laminate 100 in this order, and cut the end face 100a (each The end surface 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 protrusion height of the cutting edge B of the cutting portion 11b is higher than the protrusion height of the cutting edge B of the cutting portion 11a, and the protrusion height of the cutting edge B of the cutting portion 11c is greater than the protrusion height of the cutting edge B of the cutting portion 11b. higher.

When the cutting tool 10 is rotated in the rotation direction, the cutting portions 11d, 11e, and 11f abut the end surface 100a of the laminate 100 in this order, and cut the end surface 100a (end surface 2a of each polarizer 2). 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 protrusion height of the cutting edge B of the cutting portion 11e is higher than the protrusion height of the cutting edge B of the cutting portion 11d, and the protrusion height of the cutting edge B of the cutting portion 11f is greater than the protrusion 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 to the cutting edge B of the cutting portion 11e.

The cutting portions 11a, 11b, 11d, and 11e are used for rough cutting, and the cutting edges B are made of, for example, polycrystalline diamond. In each cutting part group, the cutting parts 11c and 11f located at the rearmost end are used for complete processing, and these cutting edges B are made of, for example, single crystal diamond. However, the material of each cutting edge B is not limited.

The circle drawn by each cutting part by the rotation of the cutting tool 10 preferably intersects the surface of each polarizer 2 in the laminate 100 (the surface of each polarizer 2 facing the Z-axis direction) almost perpendicularly. For example, the circles drawn by the cutting edges B of the cutting portions 11c and 11f having the shortest distance from the rotation axis A preferably intersect the surface of each polarizer 2 in the laminated body 100 almost perpendicularly. In other words, as shown in FIG. 5, the entry angle θ of each cutting edge B with respect to the surface of each polarizer 2 is preferably closer to 90°. In other words, the entry angle θ of each cutting edge B with respect to the surface of the layered body 100 facing the Z-axis direction is closer to 90°, the better. For example, the entry angle θ of each cutting edge B of the cutting portions 11c and 11f with the shortest distance from the rotation axis A is preferably closer to 90°. In order to make the entry angle θ close to 90°, the diameter of the cutting surface S of the cutting tool 10 is preferably greater than the thickness of the laminated body 100. In addition, the diameter of the cutting surface S of the cutting tool 10 is preferably a size sufficient to uniformly cut each end surface of all the stacked polarizing plates 1A. As shown in FIGS. 4 and 5, the height of the layered body 100 is preferably approximately the same as the height of the rotation axis A of the cutting tool 10. In other words, the position of the laminated body 100 in the direction (Z-axis direction) parallel to the end surface 2a of each polarizer 2 is preferably approximately the same as the position of the rotation axis A of the cutting tool 10 in the same direction. In other words, the position of the laminated body 100 in the direction parallel to the end face 100a of the laminated body 100 is preferably substantially the same as the position of the rotation axis A of the cutting tool 10 in the same direction. The thickness of the layered body 100 may be adjusted for the purpose of adjusting the entry angle θ of the cutting edge B. In other words, the purpose of adjusting the entry angle θ of the cutting edge B is to adjust the number of polarizing plates 1A constituting the laminated body 100. Compared with the diameter of the cutting tool 10, the smaller the thickness of the layered body 100 is, the closer the entry angle θ of the cutting edge B is to 90°. The thickness of the layered body 100 may be adjusted for the purpose of adjusting the relative positional relationship between the layered body 100 and the rotation axis A of the cutting tool 10. In other words, it is also possible to adjust the relative positional relationship between the laminated body 100 and the rotation axis A of the cutting tool 10 to adjust the number of polarizing plates 1A constituting the laminated body 100. As described above, the entry angle θ of each cutting edge B is adjusted to be approximately vertical, 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 control the average height Rc of the roughness curve elements of the end surface 2a of the polarizer 2 of the polarizer 1 within the range of 0.05 to 1.7 μm. Furthermore, the entry angle θ of each cutting edge B is adjusted to be approximately vertical, 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, thereby making it easy to adjust The root mean square thickness Rq of the side portion 2as of the polarizer 2 of the polarizer 1 is adjusted to be in the range of 0.03 to 0.15 μm. The number of revolutions of the cutting tool 10 required to control Rc and Rq within the above-mentioned range can be grasped by preliminary experiments. In order to adjust the relative positional relationship between the laminated body 100 and the rotation axis A of the cutting tool 10, the cutting tool 10 can move freely in a direction parallel to the end face 100a of the laminated body 100 (end face 2a of each polarizer 2). For example, the position of the cutting tool 10 can be freely adjusted in the Z-axis direction (up and down direction). At this time, the position of the laminated body 100 in the Z-axis direction may be fixed. The laminated body 100 is movable in a direction parallel to the end face 100a of the laminated body 100 (the end face 2a of each polarizer 2). For example, the position of the laminated body 100 in the Z-axis direction (for example, the vertical 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 polarizing plate 1A constituting the laminated body 100, the polarizing plate 2 is preferably located above the protective film 3. Furthermore, the elastic modulus of the protective film 3 is preferably higher than the elastic modulus of the polarizer 2. As shown in FIGS. 2 to 5, each cutting edge B of the cutting tool 10 moves from the upper side of the laminated body 100 to the lower side. Therefore, when the polarizer 2 is located above the protective film 3, each cutting edge B first contacts the polarizer 2 and then the protective film 3. In other words, each cutting edge B enters the polarizer 2 with a low elastic modulus, and then enters the protective film 3 with a high elastic modulus. When the polarizer 2 and the protective film 3 are arranged in this way, it is easy to adjust the average height Rc of the thickness curve element of the end surface 2a of the polarizer 2 within the range of 0.05 to 1.7μm, and it is easy to adjust the side 2as of the polarizer 2 The root-mean-square thickness Rq is adjusted within 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 face 100a of the laminated body 100 (the end face 2a of each polarizer 2) is gradually cut. At this time, the position of the laminated body 100 can be fixed. In the direction (Y direction) parallel to the end surface 100a of the layered body 100, the layered body 100 may be approached to the cutting tool 10 at a constant speed. As the layered body 100 moves, the end face 100a of the layered body 100 (end face 2a of each polarizer 2) is gradually cut. At this time, the position of the cutting tool 10 may be fixed.

With the above-mentioned cutting method, the size of each polarizing plate 1A constituting the laminated body 100 can be adjusted with higher accuracy 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-mentioned embodiments at all.

For example, the polarizing plate may include: a polarizer, a first optical film (such as a protective film) laminated on the polarizer, a pressure sensitive adhesive layer laminated on the first optical film, and a pressure sensitive adhesive layer laminated on The second optical film (for example, reflective polarizer).

The first or second optical film can also be: a film with anti-glare function, a film with anti-surface reflection function, reflective film, semi-transmissive reflective film, viewing angle compensation film, release film, optical compensation layer, touch Control induction 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.

[Example]

Examples and comparative examples are listed below to further specifically illustrate the content of the present invention. In addition, the present invention is not limited to the following examples.

[Example 1] (1) Production of polarizer

Prepare a polyvinyl alcohol film with a thickness of 20 μm. The average degree of polymerization of this polyvinyl alcohol film is about 2400, and the degree of saponification is more than 99.9 mol%.

The polyvinyl alcohol film was stretched about 4 times uniaxially in a dry manner. While maintaining the stretched state of the polyvinyl alcohol film caused by stretching, the polyvinyl alcohol film is immersed in pure water at 40°C for 1 minute. Then, the polyvinyl alcohol film was immersed in the first dyeing solution (aqueous solution) for 60 seconds. The temperature of the first dyeing solution was adjusted to 28°C. The mass ratio of iodine: potassium iodide: water in the first staining solution is 0.1:5:100. Then, the polyvinyl alcohol film was immersed in the second dyeing solution (aqueous solution) for 300 seconds. The temperature of the second dyeing solution was adjusted to 68°C. The mass ratio of potassium iodide: boric acid: water in the second dyeing solution is 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. Through the above procedure, a polarizer belonging to a long strip film is obtained. The polarizer is attached to a polyvinyl alcohol film stretched along one axis to adsorb and align iodine. The thickness of the polarizer is 7 μm.

(2) Preparation of water-based adhesive

The polyvinyl alcohol powder was dissolved in 95°C hot water to prepare a polyvinyl alcohol aqueous solution. The concentration of polyvinyl alcohol in the aqueous solution was adjusted to 3% by mass. The polyvinyl alcohol powder uses "KL-318" manufactured by KURARAY Co., Ltd. The average degree of polymerization of the polyvinyl alcohol powder was 1800. The crosslinking agent is mixed with the polyvinyl alcohol aqueous solution to obtain an aqueous adhesive. The crosslinking agent is "Sumirez Resin 650" manufactured by Taoka Chemical Industry Co., Ltd. The mass of the crosslinking agent added to the polyvinyl alcohol aqueous solution was adjusted to 1 part by mass relative to 2 parts by mass of the polyvinyl alcohol powder.

(3) Production of single-sided protective polarizer

The above-mentioned polarizer is continuously transported in its longitudinal direction. While transporting the polarizer, the protective film is continuously sent out from the reel body, the protective film is transported, and the protective film is corona treated. The protective film uses the ZEONOR film "ZF 14-023" manufactured by Japan's Zeon Co., Ltd. The thickness of the protective film is 23 μm. The polarizer and the protective film are transported, while the release film is continuously sent out from the reel body, and the release film is transported. As the peeling film, "KC8UX2MW", a triacetyl cellulose film (TAC film) manufactured by Konica Minolta Co., Ltd., was used. The thickness of the release film was 80 μm. The peeling film was not subjected to saponification treatment.

Next, the above-mentioned water-based adhesive is interposed between the polarizer and the protective film, and pure water is interposed between the polarizer and the release film, and these are sandwiched by a pair of laminating rollers, thereby obtaining a laminated film. This laminated film is provided with: a polarizer, a water-based adhesive layer laminated on one surface of the polarizer, a protective film laminated on the water-based adhesive layer, a pure water layer laminated on the other surface of the polarizer, and laminated For the peeling film of the pure water layer. This laminated film is transported to a drying device to dry the water-based adhesive layer and at the same time volatilize and remove the pure water layer. The temperature in the drying device was adjusted to 80°C. The drying time is 300 seconds. The peeling film was peeled from the laminated body after drying, and the single-sided protective polarizing plate was obtained. This single-sided protective polarizer is provided with a polarizer, a dried water-based adhesive layer laminated on one surface of the polarizer, and a protective film laminated on the water-based adhesive layer.

(4) Production of polarizing plate with brightness enhancement film

On the surface of the polarizer provided in the above-mentioned single-sided protective polarizer, the brightness enhancement film is bonded via the pressure-sensitive adhesive layer to obtain the polarizer with the brightness enhancement film. When bonding, adjust the orientation of the single-sided protective polarizer and the brightness enhancement film so that the extension direction of the polarizer and the extension axis of the brightness enhancement film become parallel. The pressure-sensitive adhesive layer uses acrylic resin. The brightness enhancement film uses the "APF" of the reflective polarizer manufactured by 3M Co., Ltd.

(5) Production of polarizing plate with partition

Prepare a film-like separator covered with a pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer uses acrylic resin. The separator is attached to the surface of the brightness enhancement film provided in the above-mentioned polarizing plate with brightness enhancement film via a pressure-sensitive adhesive layer to obtain a polarizing plate with the separator.

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

(6) Cutting

The above-mentioned polarizing plate with separator was cut into a size of 120mm×70mm to obtain 100 polarizing plates. Super Cutter is used for cutting. The structure, composition and dimensions of 100 polarizing plates are the same. Align the four sides of the 100 polarizing plates, and stack the 100 polarizing plates to obtain a laminate. Hereinafter, for the convenience of description, the laminated body including 100 polarizing plates is regarded as the same as the laminated body 100 shown in FIGS. 4 and 5. Using a cutting tool, the four end faces 100a of the laminated body 100 are cut. The cutting methods of the four end faces 100a are completely the same. The cutting tool used in the example is the same as the cutting tool 10 shown in FIGS. 2 to 5 except that the first cutting part group and the second cutting part group have five cutting parts, respectively. In the following, for convenience of description, the cutting tool used in the embodiment is regarded as the same as the cutting tool 10 shown in FIGS. 2 to 5. Hereinafter, the Z-axis direction in each figure is regarded as the upward 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 located on the protective film 3 in each polarizing plate 1A.

The five cutting edges B of each cutting part group are arranged on the cutting surface S so that the protrusion heights of the five cutting edges B gradually increase in the direction opposite to the direction of rotation of the cutting tool 10. Furthermore, the five cutting parts of each cutting part group are arranged so that the distance from the rotation axis A to the cutting edge B of the cutting part is gradually shortened in the direction opposite to the rotation direction of the cutting tool 10 On the cutting surface S. A total of 10 cutting parts constituting the first cutting part group and the second cutting part group are arranged at equal intervals so as to surround the rotation axis A. The height of a pair of cutting edges B facing each other across the axis of rotation A is the same. The distance between the cutting edge B and the rotation axis A of a pair of cutting parts opposed to each other across the rotation axis A is the same. Each cutting edge group of the cutting tool 10 has five cutting edges B with different heights. Therefore, one rotation of the cutting tool 10 is equivalent to five stages of cutting with different depths.

In cutting the end surface 100a of the laminated body 100, a pair of cutting tools 10 are used. The cutting surfaces S of the pair of cutting tools 10 face 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 so that the rotation axis A of the cutting tool 10 becomes horizontal. The position of each cutting tool 10 is fixed, and each cutting tool 10 is rotated about the rotation axis A as the center. The direction of the end face 100a of the laminated body 100 is adjusted so that the end face 100a of the laminated body 100 is perpendicular to the rotation axis A (the normal line of the cutting surface S) of the cutting tool 10. Furthermore, the orientation of the layered body 100 is adjusted so that the surface of the layered body 100 becomes horizontal.

A synthetic resin disc having the same thickness as the laminated body 100 and a smaller circle than the laminated body 100 is arranged under the laminated body 100, and the height at which the laminated body 100 is arranged is adjusted. As shown in Figs. 4 and 5, by adjusting the height of the layered body 100, the entry angle θ of each cutting edge B to the surface of each polarizer 2 in the layered body 100 becomes substantially perpendicular, and the layered body 100 is The height of the arrangement becomes 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 is 60 mm.

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

In each polarizer 1, since the polarizer 2 is arranged on the protective film 3, during one revolution of the cutting tool 10, each cutting edge B of the cutting tool 10 first cuts the end surface of each polarizer 2 in the laminate 100, Then, the end surface of each protective film 3 adjacent to each polarizer 2 is cut.

When the time for the layered body 100 to move 1 mm in the horizontal direction is regarded as the unit time, the number of rotations of the cutting tool 10 per unit time is adjusted to 10.2 times.

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

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

According to the following procedure, the average height Rc of the thickness curve element of the end surface 2a of the polarizer 2 of the polarizing plate 1 of Example 1 was measured. The end face 2a of the polarizer 2 to be measured means the end face cut by the cutting tool 10. Rc is measured using the 3D measurement laser microscope "OLS4100" manufactured by Olympus Co., Ltd. Five polarizing plates 1 were randomly selected from the 100 polarizing plates of Example 1. The Rc of two end surfaces 2a perpendicular to the extending axis direction of the polarizer 2 among the four end surfaces of the polarizer 2 included in one polarizer 1 is measured, and the average value of Rc of the two end surfaces 2a is calculated. The average value of Rc of each of the polarizers 2 included in the five polarizing plates 1 is calculated by the same method, and the average value of these five Rc is further averaged. The Rc of Example 1 calculated by the above procedure is 0.07 μm.

(7-2) Determination of Root Mean Square Rq

The root-mean-square thickness Rq of the side portion 2as of the end face 2a of the polarizer 2 of the polarizing plate 1 of Example 1 was measured by the following procedure. The end face 2a of the polarizer 2 to be measured means the end face cut by the cutting tool 10. Rq is measured using the 3D measurement laser microscope "OLS4100" manufactured by Olympus Co., Ltd. Five polarizing plates 1 were randomly selected from the 100 polarizing plates of Example 1. Among the four end surfaces of the polarizer 2 included in one polarizing plate 1, Rq of two end surfaces 2a perpendicular to the direction of the extension axis of the polarizer 2 is measured, and the average value of Rq of the two end surfaces 2a is calculated. The average value of the Rq of each of the polarizers 2 included in the five polarizing plates 1 is calculated by the same method, and the average value of the five Rqs is further averaged. The Rq of Example 1 calculated by the above procedure is 0.031 µm.

(8) Thermal shock test

According to the following procedure, a thermal shock test was carried out using a piece of the polarizing plate of Example 1 (the polarizing plate after cutting processing).

The separator was peeled off from the polarizing plate with the separator, and the polarizing plate was attached to the alkali-free glass plate through the adhesive layer to obtain a test sample. The alkali-free glass plate uses "Eagle-XG" manufactured by Corning. The sample was sealed in the autoclave for 20 minutes, and pressure treatment was applied to the sample. The temperature in the autoclave was maintained at 50°C. The pressure in the autoclave was maintained at 5 MPa. Place the pressure-treated sample in a gas environment with a temperature of 23°C and a relative humidity of 60% for 1 day.

Set the sample after the above steps in the test tank of the thermal shock tester. In addition, the cycle including the following steps 1 to 3 was repeated 12 times. The thermal shock tester uses "TSA-301L-W" manufactured by ESPEC Corporation.

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

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

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

After repeating the cycle 12 times, the sample is taken out of the test tank. Then, the edge of the sample was observed with an optical microscope, and it was checked whether there was a crack on the end surface 2a of the polarizer 2 or not. The optical microscope uses the "VHX-5000" manufactured by Keyence Corporation. The number of cracks per unit length from the end surface 2a of the polarizer 2 is determined. "Unit length" refers to a line segment perpendicular to the thickness direction of the polarizer and a length of 10mm in the end face of the polarizer. The "number of ruptures per unit length" means the number of ruptures interlaced between the end surface of the polarizer and the unit length. The number of ruptures in Example 1 was zero.

(9) Evaluation of the dimensional accuracy 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 range of the target value ±50 μm. The measured value of the length of one side of the polarizing plate of Example 1 is within the tolerance range of the target value ±50 μm. In other words, it was confirmed that the dimensional accuracy of the polarizing plate of Example 1 was high.

[Examples 2 to 9]

In Examples 2 to 9, 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 process of Examples 5 to 7 and 9, the synthetic resin disc was not arranged under the laminated body 100. In other words, in each cutting process of Examples 5 to 7 and 9, the height of the layered body 100 is lower than that of Example 1. Therefore, in the cutting process of each of Examples 5 to 7 and 9, 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. In addition, in the cutting process of each of Examples 5 to 7 and 9, the height at which the layered body 100 is arranged is not approximately the same as the height of the rotation axis A of the cutting tool 10.

Except for the above-mentioned matters concerning the cutting process, the polarizing plates of Examples 2 to 9 were produced in the same manner as in Example 1. The Rc and Rq of each of Examples 2 to 9 were measured in the same manner as in Example 1. The Rc and Rq of each of Examples 2 to 9 are shown in Table 1 below. In the same manner as in Example 1, the number of breaks in each of Examples 2 to 9 was measured. 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 ruptured end on the end face of the polarizer to the other ruptured end. The number of ruptures and the length of ruptures in each of Examples 2 to 9 are shown in Table 1 below. The length of the rupture shown in Table 1 is the longest rupture length among the ruptures formed on the end face of each polarizer. The dimensional accuracy of each polarizing plate of Examples 2 to 9 was evaluated by the same method as Example 1. The dimensional accuracy of each polarizing plate 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 disc was not arranged under the laminated body 100. In other words, in the cutting process of Comparative Example 1, the height at which the layered body 100 is arranged is lower than that of Example 1. 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 layered body 100 is not perpendicular. Furthermore, in the cutting process of Comparative Example 1, the height at which the layered body 100 is arranged is not approximately the same as the height of the rotation axis A of the cutting tool 10. In addition, in the cutting process of Comparative Example 1, the number of revolutions of the cutting tool 10 per unit time was adjusted to the values shown in Table 1 below.

The polarizing plate of Comparative Example 1 was produced in the same manner as in Example 1 except for the above-mentioned matters concerning the cutting process. The 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 ruptures and the length of ruptures of Comparative Example 1 were measured in the same manner as in Examples 1 to 9. The number of ruptures and the length of ruptures 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]

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

The number of cracks in 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 is outside the tolerance range of the target value ±50 μm. In other words, it was confirmed that the dimensional accuracy of the polarizing plate of Comparative Example 2 was low.

〔Industrial availability〕

The polarizing plate of the present invention can be applied to, for example, optical components that are attached to liquid crystal cells or organic EL elements to form image display devices such as liquid crystal televisions, organic EL televisions, or smartphones.

1‧‧‧Polarizer

2‧‧‧Film-like polarizer

2a‧‧‧The end face of the polarizer

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

3‧‧‧Protection film (the first optical film)

4‧‧‧Reflective polarizer (second optical film)

5‧‧‧Pressure-sensitive adhesive layer

S1‧‧‧First side

S2‧‧‧Second side

S3‧‧‧The third side

S4‧‧‧The fourth side

Claims (4)

A polarizing plate is provided with a film-like polarizer and a first optical film laminated on one surface of the polarizer, the polarizer is a stretched film containing polyvinyl alcohol-based resin, and the first optical film includes At least one of the cellulose resin, polyolefin resin, cyclic olefin resin, acrylic resin, and polyester resin is one of the end faces of the polarizer that is perpendicular to the direction in which the polarizer extends The average height Rc of the roughness curve elements is 0.05 to 1.7 μm . The polarizing plate described in claim 1, wherein the first side among the sides surrounding one of the end faces of the polarizer is adjacent to the first optical film, and among the sides surrounding the end faces The second side is located on the opposite side of the first side, and the root mean square thickness Rq of the portion along the second side in the end surface is 0.03 to 0.15 μm. The polarizing plate described in item 1 or item 2 of the scope of patent application further includes 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 described in any one of items 1 to 3 of the scope of patent application.

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