TWI722114B - Polarizing plate and image display device - Google Patents

Abstract

An object of the present invention is to provide a polarizing plate capable of suppressing light leakage and peeling of optical film.

The polarizing plate (1) comprises a film-like polarizer (7) and a plurality of optical films (3, 5, 9, 11, 13) overlapping with the polarizer (7). The verticality (a/b) of the end face (21) of the polarizing plate (7) is 0.00 or more and less than 0.35. The width (W) of the depolarizer (23) at the portion (3e) along the end face (21) of the end portion of the surface of the polarizing plate (7) is 0.00 μm or more and less than 35 μm.

Description

Polarizing plate and image display device

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

The polarizing plate is one of the optical components that constitutes an image display device such as a liquid crystal TV, an organic EL (electroluminescence) TV, or a smart phone. As shown in Patent Document 1 below, the polarizing plate includes a film-like polarizer and an optical film (for example, a protective film) that overlaps the polarizer.

[Prior Technical Literature] [Patent Literature]

[Patent Document 1] JP 2002-303730 A

Since most general video display devices such as televisions and smart phones have quadrangular screens, the conventional polarizers equipped in video display devices are also quadrangular, and all of them have the same polarization ability. On the other hand, a special image display device has a special shape according to these uses, and the conventional polarizing plate equipped in the device also has a special shape. For example, in order to apply polarizing plates to the shadows used in smart watches or car meters. For display devices, it is necessary to process the polarizing plate and make it into a shape corresponding to the shape of a smart watch or car meter (such as a circular shape). Due to the diversification of the use and purpose of the polarizing plate, there must be a method to process the polarizing plate into various shapes according to the purpose and purpose.

However, when the polarizing plate is cut by a conventional mechanical cutting method (for example, cutting processing), the cutting surface (end surface) of the polarizing plate is inclined, and cracks are formed near the cutting surface (end surface). The inclination and cracks of the end face of the polarizing plate damage the polarization ability near the end face and cause light leakage. The so-called "light leakage" refers to the phenomenon that light whose vibration direction is parallel to the absorption axis of the polarizer passes through the polarizer. In addition, when the polarizing plate is cut and processed by a mechanical cutting method, a part of the optical film constituting the polarizing plate is peeled from the polarizer, and the adjacent optical films are partially peeled from each other. Such delamination easily occurs in the vicinity of the cut surface (end surface) of the polarizing plate.

Instead of the mechanical cutting method described above, when the polarizing plate is processed by laser cutting, the polarizing plate can be easily processed into various shapes. However, in _{the case of thermal processing using a CO 2} laser or the like, there are also phenomena such as the inclining of the cut surface (end surface) of the polarizing plate and the formation of cracks near the cut surface (end surface) of the polarizing plate. Furthermore, in laser cutting, the vicinity of the cut surface (end surface) is heated by the laser, and the polarization ability is easily damaged due to the chemical deterioration of the polarizer. The so-called chemical deterioration of the polarizer, for example, discoloration or dissolution of the polarizer. In the following, the part that impairs the polarization function due to the chemical deterioration of the polarizer is referred to as the "polarization elimination part" of the polarizer. The larger the polarization elimination part, the more likely the image display device to leak light. According to the research results of the inventors of the present case, it is known that even in the case of processing (such as ablation processing) using an excimer laser with a shorter _{wavelength than the CO 2 laser, the cutting of the polarizing plate will cause the above-mentioned} technical problem.

The present invention was completed in view of the above-mentioned circumstances, and aims to provide a polarizing plate capable of suppressing light leakage and peeling of an optical film, and an image display device including the polarizing plate.

Regarding the one-sided polarizing plate of the present invention, it is provided with a film-like polarizer and a plurality of optical films superimposed on the polarizer, wherein the perpendicularity of the end face of the polarizing plate is 0.00 or more and less than 0.35, and the end of the surface of the polarizing plate The width of the polarization elimination part along the above-mentioned end face is 0.00 μm or more and less than 35 μm. The so-called "optical film" refers to the film-like members that constitute the polarizer (excluding the polarizer body). For example, the optical film includes a protective film and a release film. The so-called "surface of the polarizing plate", in other words, refers to the light-receiving surface or the opposite surface of the light-receiving surface of the polarizing plate.

The number of cracks in the portion along the aforementioned end surface may be 0 or more and 4 or less per unit length of 1 mm parallel to the aforementioned end portion.

The length of the crack along the above-mentioned end surface may be 0 μm or more and less than 50 μm.

At least one optical film in a pair of optical films sandwiching the polarizer may include triacetyl cellulose.

Regarding the polarizing plate of one aspect of the present invention, it is further provided with a hard coat layer, and the optical film may be located between the hard coat layer and the polarizer.

At least one optical film in a pair of optical films sandwiching the polarizer may include a cyclic olefin polymer.

At least one of a pair of optical films sandwiching a polarizer The film may contain polymethyl methacrylate.

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

According to the present invention, a polarizing plate capable of suppressing light leakage and peeling of an optical film and an image display device including the polarizing plate are provided.

1, 1a, 1b, 1s‧‧‧ Polarizing plate

3‧‧‧The third protective film

3e, 3e’‧‧‧The part along the end face of the end of one side surface of the polarizing plate (first end)

5‧‧‧The first protective film

7‧‧‧Polarizer

9‧‧‧Second protective film

10‧‧‧Liquid crystal cell

11‧‧‧Adhesive layer

13‧‧‧Release film

13e, 13e’‧‧‧The part along the end face of the end of the other side surface of the polarizing plate (the second end)

20‧‧‧LCD Panel

21, 21’, 21s‧‧‧end face (cutting surface)

23‧‧‧Polarization Elimination Section

25‧‧‧Crack

30‧‧‧Liquid crystal display device (image display device)

60‧‧‧Upper side polarizing plate

62‧‧‧Lower side polarizing plate

64‧‧‧Backlight

A1s, A60, A62‧‧‧absorption shaft

ID‧‧‧Intensity distribution

ILc‧‧‧Maximum value of the intensity of the light spot LS

ILe‧‧‧The intensity of the outer peripheral part Le of the excimer laser

Lc‧‧‧Center of light spot LS Lc

Le‧‧‧The outer circumference of the excimer laser

LS‧‧‧Spot

l‧‧‧The length of the crack

W‧‧‧The width of the polarization elimination part

Fig. 1 is a perspective view of a polarizing plate related to an embodiment of the present invention.

Figure 2 is a schematic view of the polarizing plate in the direction of line II-II in Figure 1 viewed in the direction of the arrow (the cross section of the polarizing plate perpendicular to the surface of the polarizing plate).

FIG. 3 is an enlarged view of a portion (region III) along the end surface of the end portion of the polarizing plate surface in FIG. 1. FIG.

Figure 4 is a schematic diagram of the excimer laser spot and the intensity distribution of the excimer laser along a straight line passing through the center of the excimer laser spot.

FIG. 5 is a schematic cross-sectional view of an image display device (liquid crystal display device) according to an embodiment of the present invention.

Fig. 6 is a schematic side view of the polarizing plate arrangement when inspecting the polarizing plate for light leakage in Fig. 6 (a), and Fig. 6(b) is a top view of the arrangement shown in Fig. 6(a) Schematic.

Hereinafter, the preferred embodiments of the present invention will be described with reference to the drawings. In the schema, the same symbols are assigned to the same constituent elements number. The present invention is not limited to the following embodiments. X, Y, and Z shown in each figure refer to 3 coordinate axes that are perpendicular to each other. The directions indicated by each coordinate axis are common to all figures.

As shown in FIG. 1, the polarizing plate 1 of this embodiment includes a film-like polarizer 7 and a plurality of optical films (3, 5, 9, 13) overlapping the polarizer 7. The polarizer 7 and the plural optical films (3, 5, 9, 13) are all quadrilaterals. The plural optical films (3, 5, 9, 13) are the first protective film 5, the second protective film 9, the third protective film 3, and the release film 13 (separator). That is, the polarizing plate 1 includes a polarizer 7, a first protective film 5, a second protective film 9, a third protective film 3, and a release film 13. The polarizing plate 1 also has an adhesive layer 11 located between the second protective film 9 and the release film 13. One side surface of the polarizer 7 overlaps with the first protective film 5, and the other side surface of the polarizer 7 overlaps with the second protective film 9. The first protective film 5 overlaps the third protective film 3. That is, the first protective film 5 is located between the polarizer 7 and the third protective film 3. On the second protective film 9, the release film 13 overlaps with the adhesive layer 11. In other words, the second protective film 9 is located between the polarizer 7 and the adhesive layer 11.

One side surface (first surface) of the polarizing plate 1 is composed of the third protective film 3. The other side surface (second surface) of the polarizing plate 1 is composed of a release film 13. The cross section of the polarizer 1 shown in FIG. 2 is perpendicular to the polarizer 7 and the optical films (3, 5, 9, 13). In other words, the cross section of the polarizing plate 1 shown in FIG. 2 is perpendicular to the Y axis and parallel to the ZX plane. In other words, the cross section of the polarizing plate 1 shown in FIG. 2 is perpendicular to the surface (light-receiving surface) of the polarizing plate 1.

The end face 21 of the polarizing plate 1 may be flat. Polarizing plate 1 The end face 21 may also be uneven. For example, the end surface 21 of the polarizing plate 1 may be concave and convex. For example, more than one film or layer of the polarizer 7, the optical film (3, 5, 9, 13), and the adhesive layer 11 may protrude from the end surface 21.

The perpendicularity of the end face 21 of the polarizing plate 1 is 0.00 or more and less than 0.35. Hereinafter, the verticality will be explained based on Fig. 2.

Among the ends of one side surface (first surface) of the polarizing plate 1, a portion along the end surface 21 is defined as a first end 3e. The end of the first surface of the polarizing plate 1 refers to the outer edge of the first surface of the polarizing plate 1 in other words. The entire first end 3e may extend in a straight line or a curved line in a direction parallel to the first surface of the polarizing plate 1 (XY plane direction). In other words, the first end 3e may be an end of the first optical film (third optical film 3) located on the first surface side of the polarizing plate 1. In other words, the first end 3e may also be a side common to the first surface of the polarizing plate 1 and the end surface 21. Among the end portions of the other side surface (second surface) of the polarizing plate 1, the portion along the end surface 21 is defined as the second end portion 13e. The entire second end portion 13e may extend in a linear shape or a curved shape in a direction parallel to the second surface of the polarizing plate 1. In other words, the second end 13e is at the end of the end surface 21 facing the first end 3e. In other words, the second end 13e is an end of the second optical film (release film 13) located on the second surface side of the polarizing plate 1. In other words, the second end 13e may also be the side common to the second surface of the polarizing plate 1 and the end surface 21. Hereinafter, as shown in FIG. 2, the first end 3e and the second end 13e are all regarded as points located on the same cross-section perpendicular to the surface of the polarizer 1. The distance between the first end 3e and the second end 13e is defined as a. The distance a is the distance parallel to the direction (XY plane direction) of the first surface and the second surface of the polarizing plate 1. The thickness of polarizer 1 (example Such as the average thickness) is defined as b. At this time, the perpendicularity of the end face 21 of the polarizing plate 1 is defined as a/b. The perpendicularity can also be defined as a'/b. a'is the distance between the first end 3e' and the second end 13e'. The distance a'is a distance in a direction parallel to the first surface and the second surface of the polarizing plate 1 (XY plane direction). The first end 3e' refers to a part along the end face 21' of the end of the first surface of the polarizing plate 1. The so-called end face 21' refers to the other end face opposite to the aforementioned end face 21. The second end 13e' refers to a part of the end of the second surface of the polarizing plate 1 along the end face 21'. The second end portion 13e', in other words, refers to the end portion facing the first end portion 3e' on the end surface 21'. a/b can be equal to a'/b. a/b may not be equal to a'/b. In the case where a/b and a'/b are different, a/b and a'/b are both 0.00 or more and less than 0.35. As long as the above definition is suitable, a and b can be measured on any end face of the polarizing plate 1, and the perpendicularity a/b of each end face can be calculated from the respective measured values of a and b. In the case of separately calculating the perpendicularity a/b of an arbitrary plurality of end faces of the polarizing plate 1, the maximum value of the calculated complex perpendicularity a/b is 0.00 or more and less than 0.35. a, a', b, and b'may be measured based on observation of the cross section of the polarizing plate 1 using an optical microscope, for example.

Since the perpendicularity a/b of the end face 21 is less than 0.35, light leakage is suppressed. When the perpendicularity a/b of the end face 21 is 0.35 or more, in the cross section (end face) of the polarizer 7 where the end face 21 is exposed, light leakage due to light refraction or the like becomes significant. The perpendicularity a/b of the end face 21 may be 0.00 or more and 0.30 or less, 0.00 or more and 0.29 or less, 0.00 or more and 0.28 or less, 0.04 or more and 0.30 or less, 0.04 or more and 0.29 or less, or 0.04 or more and 0.28 or less. The smaller the verticality a/b, the easier it is to suppress light leakage. Therefore, a 0 is ideal. That is, it is most desirable that the verticality a/b is 0. The perpendicularity a/b is 0, which means that the end surface 21 is completely perpendicular to the surface (the first surface and the second surface) of the polarizing plate 1.

The thickness b of the polarizing plate 1 may be, for example, 10 μm or more and 1200 μm or less, 10 μm or more and 500 μm or less, 10 μm or more and 300 μm or less, or 10 μm or more and 200 μm or less. The distance a between the first end 3e and the second end 13e can be any value as long as a/b is not less than 0.00 and less than 0.35.

As shown in FIG. 3, in the end portion of one side surface (first surface) of the polarizing plate 1, a polarization cancellation portion 23 may be formed along the first end portion 3e of the end surface 21. In the end portion of the other side surface (second surface) of the polarizing plate 1, along the second end portion 13e of the end surface 21, a polarization canceling portion may also be observed. The polarized light elimination part 23 is formed during the formation process (laser cutting step) of the end face 21 and is produced due to the chemical deterioration of the polarizer 7 or the optical film (3, 5, 9, 13). The polarization elimination part 23 may be continuous or discontinuous in the direction perpendicular to the surface of the polarizing plate 1 (the Z-axis direction). That is, the polarization elimination part 23 may have a depth from the surface of the polarizing plate 1. In other words, the polarization elimination part 23 may be three-dimensionally distributed. For example, the polarization elimination part 23 may be formed along the end surface 21. The polarization elimination part 23 is one of the causes of light leakage. The light leakage of the polarized light canceling part 23 is caused by the change of the chemical composition of the polarizer 7 or the optical film (3, 5, 9, 13). For example, the misalignment of polyvinyl alcohol or pigment molecules (iodine-containing compounds) constituting the polarizer 7 may cause light leakage in the polarization elimination part 23.

The width W of the polarization elimination portion 23 of the first end portion 3e is 0.00 μm or more and less than 35 μm. As shown in Figure 3, the so-called first end The width W of the polarization elimination portion 23 in 3e refers to the size of the polarization elimination portion 23 parallel to the first surface of the polarizing plate 1 (the surface of the third protective film 3), and is perpendicular to the direction of the first end 3e The size of the polarization cancellation part 23. The width W of the polarization canceling portion 23 is, in other words, the size of the polarization canceling portion 23 in the X-axis direction. Since the polarizing plate 1 is slightly transparent, the polarization elimination part 23 located on the second surface side (the surface side of the release film 13) can be observed from the first surface side (the surface side of the third protective film 3). That is, the polarization elimination part 23 observed on the first surface side (the surface side of the third protective film 3) is not necessarily formed on the first optical film (the third protective film 3). Furthermore, the polarization elimination part 23 located inside the polarizing plate 1 can be viewed from the first surface side or the second surface side. The polarization elimination part 23 located on the side of the first surface can be viewed from the side of the second surface. That is, the polarization elimination part 23 observed on the second surface side (the surface side of the release film 13) is not necessarily formed on the second optical film (the release film 13). Since the polarizing plate 1 is slightly transparent, when the surface of the polarizing plate 1 is viewed in a direction perpendicular to the surface of the polarizing plate 1 (the Z-axis direction), the three-dimensionally distributed polarization elimination parts 23 in an overlapping state can be seen. That is, the three-dimensionally distributed polarized light canceling parts 23 can be observed as a two-dimensional orthographic projection (for example, a rectangle) on the first surface (XY plane) of the polarizing plate 1.

Since the width W of the polarization canceling portion 23 is less than 35 μm, light leakage can be suppressed. When the width W of the polarization cancellation part 23 is 35 μm or more, the light leakage of the polarization cancellation part 23 becomes significant. The width W of the polarization cancellation part 23 may be 0.00 μm or more and 20 μm or less, 0.00 μm or more and 19 μm or less, or 0.00 μm or more and 18 μm or less. The smaller the width W of the polarization canceling portion 23 is, the easier it is to suppress light leakage. Therefore, the width W of the polarization canceling portion 23 is preferably 0.00 μm. That is, the non-polarized light canceling part 23 is most desirable. Polarized light The width W of the cancel portion 23 may not be fixed as long as it is within a range of 0.00 μm or more and less than 35 μm. In the case where the width W of the polarization canceling portion 23 is not constant, the maximum value of the width W of the polarization canceling portion 23 does not reach 35 μm. The width of the polarization elimination portion at the second end portion 13e is also 0.00 μm or more and less than 35 μm. That is, on the first surface and the second surface of the polarizing plate 1, the width of the polarization elimination portion 23 is both 0.00 μm or more and less than 35 μm. At the first end 3e' and the second end 13e', the widths of the respective polarization canceling portions 23 are both 0.00 µm or more and less than 35 µm.

On the first end 3e on the first surface, a crack 25 may be formed. The other first end 3e' on the first surface may also have a crack 25 formed. The second end 13e on the second surface may also have cracks 25 formed. The other second end 13e' on the second surface may also have a crack 25 formed. The crack 25 may be formed along the first surface (the surface of the third protective film 3). The crack 25 may also be formed along the second surface (the surface of the release film 13). The cracks 25 may be formed continuously or discontinuously in the direction perpendicular to the surface of the polarizing plate 1 (the Z-axis direction). That is, the crack 25 may have a depth from the surface of the polarizing plate 1. In other words, the cracks 25 can be three-dimensionally distributed.

The number of cracks 25 at the first end 3e is 0 or more and 4 or less per unit length of 1 mm. The so-called "unit length of 1mm" refers to a line segment parallel to the first end 3e with a length of 1mm. The so-called number of cracks 25 per unit length of 1 mm, in other words, refers to the number of cracks 25 intersecting with a unit length of 1 mm. Since the polarizing plate 1 is slightly transparent, the cracks 25 on the second surface side (the surface side of the release film 13) can be observed from the first surface side (the surface side of the third protective film 3). That is, the crack 25 observed at the first end 3e, It is not necessarily formed on the first optical film (third protective film 3) to which the first end 3e belongs. In addition, the crack 25 located inside the polarizing plate 1 can also be observed from the first surface side (the first end 3e side). The crack 25 located inside the polarizing plate 1 can also be observed from the second surface side (the second end 13e side). The crack 25 located on the first surface side (the surface side of the third protective film 3) can be observed from the second surface side (the surface side of the release film 13). That is, the crack 25 observed at the second end 13e is not necessarily formed in the second optical film (release film 13) to which the second end 13e belongs. Since the polarizing plate 1 is slightly transparent, when the surface of the polarizing plate 1 is viewed in a direction perpendicular to the surface of the polarizing plate 1 (the Z-axis direction), three-dimensionally distributed cracks 25 in the overlapping state can be seen. That is, the three-dimensionally distributed cracks 25 can be observed as a two-dimensional orthographic projection on the first surface (XY plane) of the polarizing plate 1. The multiple cracks 25 overlapping in the direction perpendicular to the surface of the polarizing plate 1 (the Z-axis direction) can be regarded as a crack 25 on the first surface of the polarizing plate 1. That is, the multiple cracks 25 overlapping in the direction perpendicular to the surface of the polarizing plate 1 (the Z-axis direction) can be counted as one crack 25 on the surface of the polarizing plate 1.

When the number of cracks 25 is 4 or less, it is easier to suppress light leakage. The length l of the crack 25 may be 0 μm or more and less than 50 μm. The length l of the crack 25 is the length of the crack 25 viewed in the direction perpendicular to the surface of the polarizing plate 1 (Z-axis direction), and is the shortest distance between one end of the crack 25 and the first end 3e. In the case where the length l of the crack 25 is less than 50 μm, it is easier to suppress light leakage to the extent that it can be recognized. The smaller the number of cracks 25 and the shorter the cracks 25, the easier it is to suppress light leakage. Furthermore, the smaller the number of cracks 25 and the shorter the cracks 25, the higher the mechanical strength of the polarizing plate 1 and the easier it is to suppress the damage of the polarizing plate 1 in the manufacturing process of the image display device. then there is not Cracking 25 is the most ideal. The number of cracks at the second end 13e may also be 0 or more and 4 or less per unit length (1 mm). That is, on the first surface and the second surface of the polarizing plate 1, the number of cracks per unit length (1 mm) can be 0 or more and 4 or less. The length of the cracks at the second end 13e can be 0 μm or more and less than 50 μm. That is, the length of the cracks on the first surface and the second surface of the polarizing plate 1 can be 0 μm or more and less than 50 μm. The number of cracks at the first end 3e' and the second end 13e' may be 0 or more and 4 or less per unit length (1 mm). The length of the respective cracks at the first end 3e' and the second end 13e' can also be 0 μm or more and less than 50 μm.

The manufacturing method of the polarizing plate 1 of this embodiment includes: stacking a film-like polarizer and a plurality of optical films to form a laminated body; and irradiating the laminated body with pulse waves of an excimer laser to cut the laminated body Step (cutting step); the output of the excimer laser is less than 20W; the intensity of the outer circumference of the spot of the excimer laser is greater than 80% of the maximum value of the spot intensity; the condensing diameter of the excimer laser is greater than 50μm; The repetition frequency of the molecular laser does not reach 1000 Hz.

In the above-mentioned laminated body, the cut surface formed in the portion irradiated by the excimer laser corresponds to the end surface 21 of the polarizing plate 1. In the following, each step is described in detail.

The laminated body can be made of polarizer 7 and various optical films (3, 5, 9 and 13) are obtained by bonding or repeatedly bonding optical films to each other. Furthermore, the adhesive layer 11 can be formed by, for example, coating an adhesive on the surface of the second protective film 9.

The excimer laser can be any of the following.

F ₂ laser (oscillation wavelength: 157nm)

ArF laser (oscillation wavelength: 193nm)

KrF laser (oscillation wavelength: 248nm)

XeCl laser (oscillation wavelength: 308nm)

XeF laser (oscillation wavelength: 351nm)

The oscillation wavelength of excimer lasers is much shorter than that of other lasers. For example, the _{oscillation wavelength of the CO 2} laser is 9.4 μm or 10.6 μm. When a short-wavelength excimer laser irradiates the laminated body, it is easy to instantaneously decompose and sublimate the polymer constituting the polarizer 7 and each optical film (3, 5, 9, 13), and suppress the accumulation of the excimer laser irradiation The heating of the body. Therefore, in the part irradiated by the excimer laser, it is easy to instantly form a cut surface with small verticality (the end face 21 of the polarizing plate 1), and it also suppresses the polarizer 7 and the optical films (3, 5, 9) caused by heat. , 13) Chemical deterioration. On the other hand, when a long-wavelength laser irradiates the laminated body, the temperature is likely to rise in the part irradiated by the laser, but it is difficult to cause the high temperature of the polarizer 7 and the optical films (3, 5, 9, 13). Decomposition of molecules ‧ sublimation. That is, starting from the melting and deformation of the part heated by the laser irradiation, the cut surface (the end surface 21 of the polarizing plate 1) is formed. Therefore, assuming that a laser with a longer wavelength than the excimer laser is used, it is difficult to control the verticality of the end face 21 of the polarizing plate 1, and because of the polarization of the polarizer 7 and the optical films (3, 5, 9, 13) The chemical deterioration makes it easy to form the polarization elimination part 23.

The output of the excimer laser is 1W or more and less than 20W. When the output of the excimer laser is 20 W or more, the crack 25 is likely to be formed in the vicinity of the cut surface, and the width W of the polarization elimination portion 23 is likely to increase. The output of the excimer laser can be above 5W and below 8W.

As shown in Figure 4, the spot LS of the excimer laser is circular. The intensity distribution ID of the excimer laser spot LS along a straight line passing through the center Lc of the excimer laser spot LS is a top hat type. In other words, the light spot LS is the cross section of the excimer laser perpendicular to the traveling direction of the excimer laser. The perpendicularity a/b of the cut surface (end face 21 of the polarizing plate 1) formed by using the top hat type excimer laser is the same as the cut surface formed by using the Gaussian excimer laser (polarizing plate 1). The verticality a/b of the end face 21) is easily smaller. The intensity Ile of the peripheral portion Le outside the light spot of the excimer laser is 80% greater than the maximum value ILc of the intensity of the light spot LS and 100% or less of ILc. In other words, (ILe/ILc)×100 is greater than 80% and 100% or less. In other words, {(ILc-ILe)/ILc}×100 is more than 0% but less than 20%. In other words, ILc is the average intensity of the flat portion (top) of the intensity distribution ID. In other words, ILc may also be the intensity of the center Lc of the light spot LS. When ILe is 80% or less of ILc, the perpendicularity a/b of the cut surface (end surface 21 of the polarizing plate 1) tends to increase. In other words, when (ILe/ILc)×100 is 80% or less, the perpendicularity a/b of the cut surface (the end surface 21 of the polarizing plate 1) is likely to increase. In other words, when {(ILc-ILe)/ILc}×100 is 20% or more, the perpendicularity a/b of the cut surface (the end face 21 of the polarizing plate 1) tends to increase. ILe can be more than 90% and less than 95% of ILc. In other words, (ILe/ILc)×100 may be 90% or more and 95% or less. In other words, {(ILc-ILe)/ILc}×100 may be 5% or more and 10% or less. The unit of the intensity ILe and the intensity ILc may be, for example, W/m ² . In a modification of this embodiment, the light spot of the excimer laser may also be an elongated rectangle.

The condensing diameter of the excimer laser is greater than 50μm and less than 2000μm. When the condensing diameter of the excimer laser is less than 50 μm, the perpendicularity a/b of the cut surface (the end face 21 of the polarizing plate 1) tends to become large. The so-called condensing diameter of the excimer laser, in other words, refers to the diameter of the spot LS of the excimer laser. The condensing diameter of the excimer laser can be 600 μm or more and 1000 μm or less.

The repetition frequency of excimer lasers is above 10 Hz and less than 1000 Hz. When the repetition frequency of the excimer laser is 1000 Hz or more, the crack 25 is likely to be formed, and the polarization elimination part 23 is also likely to be formed. The repetition frequency of the excimer laser can be above 100Hz and below 500Hz.

The polarizer 7 may be a film-like polyvinyl alcohol-based resin produced through steps such as stretching, dyeing, and cross-linking. The detailed description of the polarizer 7 is as follows.

For example, first, the film-like polyvinyl alcohol-based resin is stretched in the uniaxial direction or the biaxial direction. The polarizer 7 extending in the uniaxial direction tends to have a high dichroic ratio. After stretching, the polyvinyl alcohol-based resin is dyed with iodine or a dichroic dye (polyiodine) using a dyeing solution containing potassium iodide or the like. The dyeing solution may contain boric acid, zinc sulfate, or zinc chloride. The polyvinyl alcohol resin can also be washed with water before dyeing. By washing with water, dirt and blocking inhibitors can be removed from the surface of the polyvinyl alcohol resin. Moreover, as a result of the swollen polyvinyl alcohol-based resin washed with water, it is easy to suppress staining (uneven dyeing). The dyed polyvinyl alcohol-based resin is treated with a solution of a crosslinking agent (for example, an aqueous solution of boric acid) for crosslinking. After being treated with a crosslinking agent, wash the polyvinyl alcohol with water The resin is then dried. After the above sequence, the polarizer 7 can be obtained. The polyvinyl alcohol resin can be obtained by saponifying a polyvinyl acetate resin. Polyvinyl acetate-based resins, such as polyvinyl acetate which is a single polymer of vinyl acetate, or a copolymer of vinyl acetate and other monomers copolymerizable therewith (for example, ethylene-vinyl acetate copolymer). Other monomers that can be copolymerized with vinyl acetate, in addition to ethylene, may be unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, or acrylamides with ammonium groups. Polyvinyl alcohol resin can be modified by aldehydes. A modified polyvinyl alcohol-based resin, such as partially formalized polyvinyl alcohol, polyvinyl acetal, or polyvinyl butyral. The polyvinyl alcohol-based resin may be a polyolefin-based alignment film such as a dehydrated polyvinyl alcohol or a dehydrochloric acid-treated polyvinyl chloride. Dyeing can be done before extension, or extension can be done in dyeing solution. The length of the extended polarizer 7 may be, for example, 3 to 7 times the length before the extension.

The thickness of the polarizer 7 is, for example, 1 μm or more and 50 μm or less, or 4 μm or more and 30 μm or less. Generally, when the thin polarizer 7 extends along one axis, cracks 25 are likely to be formed along the extending direction during the hole-opening step or the slicing step. However, the formation of cracks 25 can be suppressed by the above-mentioned cutting step using an excimer laser.

The first protective film 5 and the second protective film 9 may be optically transparent thermoplastic resins as long as they are transparent thermoplastic resins. The resin constituting the first protective film 5 and the second protective film 9, such as chain polyolefin resin, cyclic olefin polymer resin (COP resin), cellulose ester resin, polyester resin, polycarbonate -Based resin, (meth)acrylic resin, polystyrene-based resin, or a mixture or copolymer of these. The composition of the first protective film 5 may be exactly the same as the composition of the second protective film 9. The composition of the first protective film 5 may be different from the composition of the second protective film 9.

Chain polyolefin resin, for example, a single polymer of chain olefin such as polyethylene resin or polypropylene resin. The chain polyolefin resin may be a copolymer composed of two or more chain olefins.

The cyclic olefin polymer resin (cyclic polyolefin resin) may be, for example, a ring-opening (co)polymer of cyclic olefin or an addition polymer of cyclic olefin. The cyclic olefin polymer resin may be, for example, a copolymer (for example, a random copolymer) of a cyclic olefin and a chain olefin. The chain olefin constituting the copolymer is, for example, ethylene or propylene. The cyclic olefin polymer-based resin may be a graft polymer or hydrogenated products of the above-mentioned polymer modified by an unsaturated carboxylic acid or a derivative thereof. The cyclic olefin polymer-based resin is, for example, a norbornene-based resin using a norbornene-based monomer such as a norbornene or a polycyclic norbornene-based monomer.

Cellulose ester resins, such as cellulose triacetate (triacetyl cellulose (TAC)), cellulose diacetate, cellulose tripropionate, or cellulose dipropionate. These copolymers can also be used. It is also possible to use a cellulose ester-based resin in which a part of the hydroxyl group is modified with another substituent.

Polyester resins other than cellulose ester resins may also be used. The polyester resin is, for example, a polycondensate of a polyvalent carboxylic acid or a derivative thereof and a polyvalent alcohol. The polyvalent carboxylic acid or its derivative may be a dicarboxylic acid or its derivative. The polyvalent carboxylic acid or its derivative is, for example, terephthalic acid, isophthalic acid, dimethyl terephthalate, or dimethyl naphthalate. Multivalent alcohols are, for example, diols. Multivalent alcohols, such as ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol Alcohol, or cyclohexanedimethanol.

Polyester resins, for example, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, Polypropylene naphthalate, polycyclohexane dimethyl terephthalate, or polycyclohexane dimethyl naphthalate.

The polycarbonate resin is a polymer in which a polymerized unit (monomer) is bonded via a carbonate group. The polycarbonate resin may be a modified polycarbonate with a modified polymer backbone, or a copolymerized polycarbonate.

(Meth) acrylic resins, such as poly(meth)acrylate (e.g. polymethyl methacrylate (PMMA)); methyl methacrylate-(meth)acrylic acid copolymer; methyl methacrylate-( (Meth)acrylate copolymer; methyl methacrylate-acrylate-(meth)acrylic acid copolymer; methyl (meth)acrylate-styrene copolymer (such as MS resin); methyl methacrylate with Copolymers of alicyclic hydrocarbon-based compounds (for example, methyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate-norbornyl (meth)acrylate copolymer, etc.).

At least one of the pair of optical films (the first protective film 5 and the second protective film 9) sandwiching the polarizer 7 may include triacetyl cellulose (TAC). At least one of a pair of optical films (the first protective film 5 and the second protective film 9) sandwiching the polarizer 7 may contain a cyclic olefin polymer resin (COP-based resin). At least one of the pair of optical films (the first protective film 5 and the second protective film 9) sandwiching the polarizer 7 may include polymethyl methacrylate (PMMA). Both of the pair of optical films (the first protective film 5 and the second protective film 9) sandwiching the polarizer 7 may include triacetyl cellulose. Clamp the polarizer One of the pair of optical films (the first protective film 5 and the second protective film 9) of 7 may include triacetyl cellulose, and the other of the pair of optical films sandwiching the polarizer 7 may be Contains cyclic olefin polymers. One of the pair of optical films (the first protective film 5 and the second protective film 9) sandwiching the polarizer 7 may include triacetyl cellulose, and the other of the pair of optical films sandwiching the polarizer 7 A film that may contain polymethyl methacrylate. One of the pair of optical films (the first protective film 5 and the second protective film 9) sandwiching the polarizer 7 may include a cyclic olefin polymer resin, and one of the pair of optical films sandwiching the polarizer 7 Another film may contain polymethyl methacrylate. When an optical film made of TAC, COP-based resin or PMMA contacts the polarizer 7, it is difficult to reduce the perpendicularity a/b of the end face 21 due to the conventional processing method, and it is difficult to suppress the formation of the polarization elimination portion 23 and the crack 25 . However, by the above-mentioned cutting step using an excimer laser, the perpendicularity a/b of the end surface 21 is reduced, and the formation of the polarization elimination portion 23 and the crack 25 is suppressed.

The glass transition temperature Tg of the polarizer 7 or each optical film (3, 5, 9 or 13) can be 100 to 180°C or 108 to 180°C. In the case where the optical film (3, 5, 9 or 13) is composed of triacetyl cellulose (TAC), the glass transition temperature Tg of the optical film (3, 5, 9 or 13) can be 160 to 180°C . When the optical film (3, 5, 9 or 13) is made of cyclic olefin polymer resin (COP-based resin), the glass transition temperature Tg of the optical film (3, 5, 9 or 13) can be 126 To 136°C. When the optical film (3, 5, 9 or 13) is made of polymethyl methacrylate (PMMA), the glass transition temperature Tg of the optical film (3, 5, 9 or 13) can be 108 to 136°C . The glass transition temperature Tg of the polarizer 7 and each optical film (3, 5, 9, 13) is above 100°C In the case, the polarizing plate 1 has good heat resistance, and it is easy to suppress the deformation of the polarizing plate 1 caused by the heat accompanying the irradiation of the excimer laser.

The first protective film 5 or the second protective film 9 may also contain at least one selected from the group consisting of lubricants, plasticizers, dispersants, heat stabilizers, ultraviolet absorbers, infrared absorbers, anti-charge agents, and antioxidants additive.

The thickness of the first protective film 5 is, for example, 5 μm or more and 90 μm or less, 5 μm or more and 80 μm or less, or 5 μm or more and 50 μm or less. The thickness of the second protective film 9 is, for example, 5 μm or more and 90 μm or less, 5 μm or more and 80 μm or less, or 5 μm or more and 50 μm or less.

The first protective film 5 or the second protective film 9 may be a film having an optical function such as a retardation film or a brightness enhancement film. For example, by extending a film composed of the above-mentioned thermoplastic resin to form a liquid crystal layer on the film, a retardation film with an arbitrary retardation value can be obtained.

The first protective film 5 may be bonded to the polarizer 7 via an adhesive layer. The second protective film 9 may be attached to the polarizer 7 via an adhesive layer. The adhesive layer may include an aqueous adhesive such as polyvinyl alcohol, or may include an active energy ray-curable resin described later.

Active energy ray curable resin is a resin that is cured by irradiation of active energy rays. The active energy rays are, for example, ultraviolet rays, visible light, electron rays, or X-rays. The active energy ray curable resin may be an ultraviolet curable resin.

The active energy ray curable resin may be one type of resin, or may include a plurality of types of resins. For example, active energy ray curable resin can contain Cationic polymerizable curable compound or radical polymerizable curable compound. The active energy ray curable resin may contain a cationic polymerization initiator or a radical polymerization initiator for initiating the curing reaction of the above-mentioned curable compound.

The cationically polymerizable curable compound is, for example, an epoxy compound (a compound having at least one epoxy group in the molecule) or an oxetane compound (a compound having at least one oxetane ring in the molecule). The radically polymerizable curable compound is, for example, a (meth)acrylic compound (a compound having at least one (meth)acryloxy group in the molecule). The radically polymerizable curable compound may be a vinyl compound having a radically polymerizable double bond.

Active energy ray curable resin, if necessary, can contain cationic polymerization accelerator, ion scavenger, antioxidant, chain transfer agent, adhesion imparting agent, thermoplastic resin, filler, flow regulator, plasticizer, defoamer, anti-static Agent, leveling agent or solvent, etc.

The adhesive layer 11 may include, for example, a pressure-sensitive adhesive such as an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a silicone pressure-sensitive adhesive, or a urethane-based pressure-sensitive adhesive. . The thickness of the adhesive layer 11 is, for example, 2 μm or more and 500 μm or less, 2 μm or more and 200 μm or less, or 2 μm or more and 50 μm or less.

The resin constituting the third protective film 3 may be the same as the above-mentioned resins exemplified as constituting the first protective film 5 or the second protective film 9. The thickness of the third protective film 3 is, for example, 5 μm or more and 200 μm or less.

The resin constituting the release film 13 may be any of the following The first protective film 5 or the second protective film 9 is the same as the above-mentioned resin. The thickness of the release film 13 may be, for example, 5 μm or more and 200 μm or less.

Regarding the image display device of the present invention, it may be, for example, a liquid crystal display device or an organic EL display device. For example, as shown in FIG. 5, the liquid crystal display device 30 of this embodiment includes a liquid crystal cell 10, a polarizing plate 1a (first polarizing plate) superimposed on one surface (first surface) of the liquid crystal cell 10, Another polarizing plate 1b (second polarizing plate) overlapped on the other side surface (second surface) of the liquid crystal cell 10. The polarizing plates 1a and 1b shown in Fig. 5 are the same as the polarizing plate 1 shown in Figs. 1 and 2 except for the point that the release film 13 and the third protective film 3 are not provided. The polarizing plate 1 a (first polarizing plate) is attached to the first surface of the liquid crystal cell 10 via the adhesive layer 11. The polarizing plate 1a (first polarizing plate) has an adhesive layer 11 overlapping the first surface of the liquid crystal cell 10, a second protective film 9 overlapping the adhesive layer 11, a polarizing film 7 overlapping the second protective film 9, and overlapping The first protective film 5 of the polarizer 7. The other polarizing plate 1b (second polarizing plate) is attached to the second surface of the liquid crystal cell 10 via the adhesive layer 11. Another polarizing plate 1b (second polarizing plate) has an adhesive layer 11 overlapping the second surface of the liquid crystal cell 10, a second protective film 9 overlapping the adhesive layer 11, and a polarizing film 7 overlapping the second protective film 9 , Overlap the first protective film 5 of the polarizer 7. The liquid crystal cell 10 and a pair of polarizing plates 1 a and 1 b constitute a liquid crystal panel 20. The liquid crystal panel 20 and other components such as a backlight (surface light source device) constitute the liquid crystal display device 30. Other components such as the backlight are omitted in Figure 5.

Above, an embodiment of the present invention has been described, but the present invention is not limited to the above embodiment.

The shape of the polarizing plate can be various shapes depending on the application. Here, the shape of the polarizing plate refers to the shape of the entire polarizing plate as viewed from the Z direction (direction perpendicular to the surface of the polarizing plate 1) in FIGS. 1 to 3. For example, the shape of the polarizing plate may be a polygon other than a quadrangular shape. For example, the polarizing plate may also have a circular shape, an elliptical shape, or an irregular shape. The outer edge of the polarizing plate can be composed of only straight lines (a plurality of sides). Here, the outer edge of the polarizing plate refers to the outer edge of the polarizing plate viewed from the Z direction (direction perpendicular to the surface of the polarizing plate 1) in FIGS. 1 to 3. The outer edge of the polarizing plate, in other words, the end of the surface of the polarizing plate. The outer edge of the polarizing plate can only be composed of curved lines. The shapes of the polarizer 7 and the respective optical films (3, 5, 9, 13) may be various shapes depending on the application.

The number of optical films (optical films superimposed on the polarizer) included in the polarizing plate is not limited. The number of optical films included in the polarizing plate may be one. For example, in the polarizing plate 1 shown in FIGS. 1 and 2, the first protective film 5 and the second protective film 9 may not be provided with any one of the protective films, or may not be provided with the two protective films. For example, in the polarizing plate 1a (first polarizing plate) and polarizing plate 1b (second polarizing plate) shown in Fig. 5, either the polarizing plate or the second polarizing plate may not have the first protective film 5 and the second protective film Any of 9 protective films. Either the polarizing plate or the two polarizing plates of the polarizing plate 1a (first polarizing plate) and the polarizing plate 1b (second polarizing plate) shown in FIG. 5 may not have the two protective films.

The release film can be arranged on both sides of the polarizing plate through an adhesive layer.

The optical film of the polarizer can be reflective polarizing film, film with anti-glare function, film with surface anti-reflection function, reflective film, semi-transmissive reflective film, viewing angle compensation film, optical compensation layer, touch sensor Layer, charge prevention layer, or antifouling layer.

The polarizing plate can be equipped with hard coating. For example, in the polarizer 1, the first protective film 5 may be located between the hard coating layer and the polarizer 7, and the hard coating layer may be located between the first protective film 5 and the third protective film 3. In this case, the first protective film 5 may include triacetyl cellulose. The surface hardness (pencil hardness) of the hard coat layer can be H or more and 5H or less or 2H or more and 5H or less. Pencil hardness is based on Japanese Industrial Standards (JIS K5400). The pencil hardness is a hard coat within the above range, and it is not easy to be injured during the manufacturing process of the polarizing plate 1. However, since the hard coat layer is hard and brittle, when the end face (cut surface) of the polarizing plate is formed by a conventional cutting method, cracks are easily formed in the hard coat layer. However, the formation of cracks in the hard coat layer can be suppressed by the above-mentioned cutting step using an excimer laser.

The hard coat layer is, for example, a layer composed of an acrylic resin film provided with fine concavo-convex shapes on the surface. The hard coat layer may be formed of, for example, a coating film containing organic fine particles or inorganic fine particles. A method (for example, embossing method, etc.) of pressing the coating film into a roller having an uneven shape can also be used. It is also possible to use a method of forming a coating film that does not contain organic fine particles or inorganic fine particles, and then pressing the coating film into a roller having an uneven shape.

The inorganic fine particles are, for example, silica, colloidal silica, alumina, alumina sol, aluminum silicate, alumina-silica composite oxide, kaolin, talc, mica, calcium carbonate, calcium phosphate, and the like. Furthermore, the organic fine particles (resin particles) are, for example, cross-linked polyacrylic acid particles, methyl methacrylate/styrene copolymer resin particles, cross-linked polystyrene particles, cross-linked polymethyl methacrylate particles, polysiloxanes Resin particles, polyimide particles, etc.

The binder component for dispersing organic fine particles or inorganic fine particles may be selected from materials that become high hardness (hard coating). Binder component, which can be For example, ultraviolet curable resin, thermosetting resin, electron beam curable resin, etc. From the viewpoint of productivity, hardness, etc., it is preferable to use ultraviolet curable resin as a binder component.

The thickness of the hard coat layer is, for example, 2 μm or more and 30 μm or less, or 3 μm or more and 30 μm or less. When the thickness of the hard coat layer is 2 μm or more, sufficient hardness of the hard coat layer can be easily obtained, and the surface of the hard coat layer is hard to be damaged. When the thickness of the hard coat layer is 30 μm or less, the hard coat layer is less likely to be cracked, and it is easy to suppress the curl of the polarizing plate caused by the hardening shrinkage of the hard coat layer, which tends to improve productivity.

The thickness of the polarizer 7 is 30 μm or less, the single transmittance T of the polarizer 7 is 42.5 or more, and the degree of polarization P of the polarizer 7 is 99.9 or more. When the traditional polarizer is thin and the transmittance and polarization of the monomer are large, the light leakage can be easily recognized on the end face of the polarizer. However, by forming the end face 21 with a small verticality by the above-mentioned cutting step using an excimer laser, it is possible to suppress light leakage of the polarizing plate 1 provided with a thin polarizer 7 having a large monomer transmittance and a high degree of polarization.

The moisture content of the laminate composed of the three-layer film of the polarizer 7, the first protective film 5, and the second protective film 9 can be 1.0 to 5.0%, 0.5 to 5.5%, or 1.0 to 5.0%. When the moisture ratio is within the above range, it is easy to suppress the distortion of the polarizing plate 1 accompanying heating, and it is easier to suppress the light leakage of the polarizing plate 1.

In Figures 1 and 2, the second end 13e on the side of the release film 13 (the second optical film side) protrudes outward from the first end 3e on the side of the third protective film 3 (the first optical film side). But the third protective film 3 side (first optical film side) The first end portion 3e of the release film 13 may protrude outward from the second end portion 13e on the side of the release film 13 (the second optical film side). In the cutting step, when the excimer laser is irradiated on the side of the third protective film 3 (the side of the first optical film), the second end 13e on the side of the release film 13 (the side of the second optical film) is easier to The first end 3e on the side of the protective film 3 (side of the first optical film) protrudes outward. In the cutting step, when the excimer laser is irradiated on the release film 13 side (the second optical film side), the first end 3e located on the third protective film 3 side (first optical film side) is easier than the release film 13 side (the first optical film side). The second end 13e of the film 13 side (the second optical film side) protrudes outward.

The perpendicularity of all the end faces of the polarizing plate is 0.00 or more and less than 0.35, and the width of the polarization elimination part in the entire area of the end of the polarizing plate surface is 0.00 μm or more and less than 35 μm. For example, the perpendicularity of all the end faces (four end faces) of a rectangular polarizing plate is 0.00 or more and less than 0.35. When only a part of the polarizing plate is required to suppress light leakage, only the verticality of the end face of the part where the light leakage is required to be suppressed is 0.00 or more and less than 0.35. The width of the polarization elimination part at the end of this part can be Above 0.00μm is less than 35μm. For example, the perpendicularity of only a part of one end surface of the polarizing plate is 0.00 or more and less than 0.35. For example, only one end of the rectangular polarizing plate has a perpendicularity of 0.00 or more and less than 0.35. Only the pair of opposite end faces of the rectangular polarizing plate has a perpendicularity of 0.00 or more and less than 0.35. Only the verticality of the three end faces of the rectangular polarizing plate is 0.00 or more and less than 0.35.

The polarizing plate 1 may not include one or both of the third protective film 3 and the release film 13. For example, the third protective film 3 is used in the image display device The manufacturing process of the device can be peeled off and removed from the polarizing plate 1. That is, the third protective film 3 may be a temporary protective film. The release film 13 can also be peeled off and removed from the polarizing plate 1 during the manufacturing process of the image display device.

[Example]

Hereinafter, the present invention will be described in more detail through examples, but the present invention is not limited to these examples.

(Example 1)

As shown in Fig. 1, a plate-shaped laminate composed of a polarizer 7 and optical films (3, 5, 9, 13) is formed. The laminate includes a release film 13, an adhesive layer 11 superimposed on the release film 13, a second protective film 9 superimposed on the adhesive layer 11, a polarizer 7 superimposed on the second protective film 9, and a second protective film superimposed on the polarizer 7 A protective film 5 and a third protective film 3 overlapping the first protective film 5. Furthermore, not shown in FIG. 1, in Example 1, the first protective film 5 is covered with a hard coat layer, and the third protective film 3 overlaps the first protective film 5 via the hard coat layer. As the polarizer 7, stretched and dyed film-like polyvinyl alcohol is used. As the first protective film 5, a hard-coated triacetyl cellulose (TAC) film (25KCHCN-TC manufactured by Relief Printing Co., Ltd.) was used. As the second protective film 9, a film composed of a cyclic olefin polymer resin (COP-based resin) (ZF14-023-1350 manufactured by ZEON Co., Ltd., Japan) was used. As the third protective film 3, an adhesive PET protective film (AS3-304 manufactured by Fujimori Kogyo Co., Ltd.) was used. As the release film 13, PET (SP-PLR382050 manufactured by Lintec Co., Ltd.) was used. The thickness of the release film 13 is 38 μm. The thickness of the adhesive layer 11 is 20 μm. The thickness of the second protective film 9 is 23 μm. The thickness of the polarizer 7 is 12 μm. The thickness of the first protective film 5 The degree is 32μm. The thickness of the third protective film 3 is 60 μm. The thickness of the entire laminate (thickness equivalent to the thickness b of the polarizing plate 1) is 185 μm. The longitudinal width of the entire laminate is 110 mm. The lateral width of the entire laminate is 60 mm.

The pulse wave of the excimer laser is irradiated on the surface of the layered body on the third protective film 3 side to cut the layered body straight. Through the above steps, the polarizing plate 1 of Example 1 having the structure shown in Figs. 1 and 2 is obtained. The cut surface of the laminate corresponds to the end surface 21 of the polarizing plate 1. As an excimer laser, a KrF laser with an oscillation wavelength of 248 nm is used. As the excimer laser oscillator, MLI series (1000 type) manufactured by Mlase Corporation was used. The output of the excimer laser is set to 5W. As shown in Figure 4, the spot LS of the excimer laser is circular. When the intensity of the outer peripheral part Le of the light spot LS of the excimer laser is denoted as ILe, and the maximum value of the intensity of the light spot LS (the intensity of the flat top) is denoted as ILc, {(ILc-ILe)/ILc}×100 Is 5%. Hereinafter, {(ILc-ILe)/ILc}×100 is referred to as "density distribution". The condensing diameter of the excimer laser is set to 1000 μm. The repetition frequency of the excimer laser is set to 100 Hz.

The polarizing plate 1 is cut in a direction perpendicular to the surface of the polarizing plate 1 (the surface of the third protective film 3) and the end surface 21, and the cross section of the polarizing plate 1 as shown in FIG. 2 is exposed. The cross section of the polarizing plate 1 was observed with an optical microscope, and the distance a between the first end 3e and the second end 13e was measured. The perpendicularity a/b of the end face 21 is calculated from the measured value of a. The verticality is 0.07. Furthermore, as described in the above embodiment, the first end 3e is a part of the end of one side surface (first surface) of the polarizing plate 1 along the end surface 21 (cut surface). second The end portion 13e is a portion along the end surface 21 (cut surface) of the end portion of the other side surface (second surface) of the polarizing plate 1.

The first end 3e located on the side of the third protective film 3 irradiated by the excimer laser was observed with an optical microscope. Based on this observation, among the cracks (25) of the first end 3e, an attempt was made to count the number of cracks with a length l of less than 50 μm and the number of cracks with a length l of 50 μm or more. Furthermore, the definition of the number of cracks is the same as the above-mentioned embodiment. Moreover, the definition of the length l of the crack is the same as the above embodiment. As a result of the observation, in the first end 3e of the polarizing plate 1 of Example 1, there is no crack with a length l of less than 50 μm. Furthermore, in the first end 3e of the polarizing plate 1 of Example 1, there is no crack with a length l of 50 μm or more.

By the above observation using an optical microscope, an attempt was made to measure the width W of the polarization elimination portion 23 (color changing portion) at the first end portion 3e. However, at the first end portion 3e, there is no polarization canceling portion 23.

The cross section of the above-mentioned polarizing plate 1 was observed with an optical microscope, and the presence or absence of peeling (interlayer peeling) of the optical film on the end face 21 side was checked. On the end face 21 side, there is no peeling optical film of 50 μm or more. Furthermore, the so-called “50 μm” refers to the distance in the direction parallel to the surface of the polarizing plate 1.

As shown in Fig. 6 (a) and (b), the entire surface of the backlight 64 (surface light source) is covered by the lower polarizing plate 62. The lower polarizing plate 62 is a polarizing plate different from the polarizing plate of the first embodiment. The release film 13 of the polarizing plate (1s) of Example 1 was made to face the lower polarizing plate 62. The polarizing plate (1s) of Example 1 was superimposed on the lower polarizing plate 62 so that the absorption axis A1s of the polarizing plate (1s) of Example 1 was perpendicular to the absorption axis A62 of the lower polarizing plate 62. Attach the upper polarizing plate 60 is superimposed on the polarizing plate (1s) of Example 1, and is arranged such that the absorption axis A60 of the upper polarizing plate 60 is parallel to the absorption axis A1s of the polarizing plate (1s) of Example 1. The upper polarizing plate 60 is also a polarizing plate different from the polarizing plate of the first embodiment. In addition, the end face (21s) of the polarizing plate (1s) in Fig. 6 corresponds to the end face 21 of the polarizing plate 1 shown in Figs. 1 and 2.

The polarizing plate (1s) of Example 1 was arranged as described above, the backlight 64 was turned on, and the polarizing plate (1s) of Example 1 was visually observed. As a result of observation, there is no light leakage near the end face (21s) of the polarizing plate (1s).

(Examples 2 to 7, Comparative Examples 1 to 4)

In Example 6, as the excimer laser, an ArF laser (oscillation wavelength: 193 nm) was used instead of the KrF laser.

In Example 7, the same laminate as in Example 1 was used except that the release film 13, the adhesive layer 11, and the third protective film 3 were not provided. In the following, for the convenience of description, the second protective film of the polarizing plate of Example 7 is referred to as the "release film" of the polarizing plate of Example 7, and the first protective film of the polarizing plate of Example 7 is referred to as The "third protective film" of the polarizing plate of Example 7. In Table 1 below, the third protective film is denoted as "Pf" and the release film is denoted as "Sp".

In Examples 2 to 7 and Comparative Examples 1 to 4, the output, density distribution, focusing diameter, and repetition frequency of the excimer laser were set to the values shown in Table 1 below.

Except for the above matters, the laminated body was cut with an excimer laser in the same manner as in Example 1, and each of Examples 2 to 7 and Comparative Examples 1 to 4 was obtained. Polarizing plate.

Using the same method as in Example 1, the perpendicularity a/b of the end faces of the polarizing plates of Examples 2 to 7 and Comparative Examples 1 to 4 was obtained. The perpendicularity of Examples 2 to 7 and Comparative Examples 1 to 4 are shown in Table 1 below.

Using the same method as in Example 1, in Examples 2 to 7 and Comparative Examples 1 to 4, respectively, observe the third protective film irradiated by the excimer laser, count the number of cracks at the first end, and measure each turtle The length of the crack. In Examples 2 to 7 and Comparative Examples 1 to 4, the number of cracks is shown in Table 1 below. In any embodiment, the number of cracks at the first end is 4 or less. In any embodiment, the length of the crack at the first end is less than 50 μm.

Using the same method as in Example 1, in Examples 2 to 7 and Comparative Examples 1 to 4, respectively, the first end of the third protective film side was observed, and the polarization elimination part (discoloration part) at the first end was measured. width. In Examples 2 to 7 and Comparative Examples 1 to 4, the width W of the polarization elimination portion (color changing portion) is shown in Table 1 below. In any embodiment, the width of the polarization elimination portion (color changing portion) at the first end is less than 35 μm.

Using the same method as in Example 1, in Examples 2 to 7 and Comparative Examples 1 to 4, respectively, the optical film on the end surface side (cut surface side) of the polarizing plate was checked for peeling (interlayer peeling). The results are shown in Table 1 below. When there is an optical film peeling at 50 μm or more, it is described as "present" in Table 1 below. When there is no optical film peeling at 50 μm or more, it is described as "None" in Table 1 below.

Using the same method as in Example 1, in Examples 2 to 7 and Comparative Examples 1 to 4, respectively, inspect the vicinity of the end surface (cut surface) of the polarizing plate Light leak. The inspection results are shown in Table 1 below.

[Industrial Utilization Possibility]

The polarizing plate of the present invention is suitable for use as an optical member that is attached to a liquid crystal cell or an organic EL device to constitute an image display device such as a liquid crystal television, an organic EL television, or a smartphone.

3‧‧‧The third protective film

3e, 3e’‧‧‧The part along the end face of the end of one side surface of the polarizing plate (first end)

5‧‧‧The first protective film

7‧‧‧Polarizer

9‧‧‧Second protective film

11‧‧‧Adhesive layer

13‧‧‧Release film

13e, 13e’‧‧‧The part along the end face of the end of the other side surface of the polarizing plate (the second end)

21, 21’‧‧‧end surface (cutting surface)

Claims (8)

A polarizing plate, comprising: a film-like polarizer and a plurality of optical films superimposed on the polarizer; the perpendicularity of the end surface of the polarizing plate is 0.00 or more but less than 0.35; The width of the polarized light elimination portion in the part of the end face is 0.00 μm or more and less than 35 μm. The polarizing plate described in the first item of the scope of patent application, wherein the number of cracks in the portion along the aforementioned end surface is 0 or more and 4 or less per unit length of 1 mm parallel to the aforementioned end portion. The polarizing plate described in item 1 or 2 of the scope of patent application, wherein the length of the crack along the aforementioned end surface is 0 μm or more and less than 50 μm. The polarizing plate according to item 1 or 2 of the scope of the patent application, wherein at least one of the optical films of the pair of the optical films sandwiching the polarizer contains triacetyl cellulose. The polarizing plate described in item 1 or 2 of the scope of the patent application is further provided with a hard coat layer, and the optical film is located between the hard coat layer and the polarizer. The polarizing plate according to item 1 or 2 of the scope of the patent application, wherein at least one of the optical films in the pair of the optical films sandwiching the polarizing film includes a cyclic olefin polymer. The polarizing plate as described in item 1 or 2 of the scope of patent application, wherein at least one of the optical films in the pair of the optical films sandwiching the polarizer includes polymethyl methacrylate. An image display device comprising the polarizing plate as described in any one of items 1 to 7 of the scope of patent application.

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