TWI633346B - Polarizing plate and image displayer - Google Patents

Abstract

The present invention provides a polarizing plate capable of suppressing light leakage. The polarizing plate (1) includes a film-shaped polarizer (7) and a plurality of optical films (3, 5, 9, 11, 13) superposed on the polarizer (7). The perpendicularity (a / b) of the hole (21) passing through the polarizing plate (1) is 0.00 or more and less than 0.32. The width (W) of the polarized light eliminating portion (23) around the hole (21) is 0.00 μm or more and less than 32 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 constituting an image display device such as a liquid crystal television, an organic EL (electrically excited light) television, or a smart phone. As shown in Patent Document 1 below, the polarizing plate includes a film-shaped polarizer and an optical film (for example, a protective film) overlapping the polarizer.

[Prior technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2002-303730

Almost ordinary video display devices such as televisions and smart phones have a quadrangular screen, so the conventional polarizing plate equipped in the video display device is also a quadrangle, and the entire device also has polarizing capabilities. On the other hand, special image display devices have various shapes depending on such applications, and the conventional polarizing plates provided in the devices also have various shapes. For example, the image display device used in smart watches or car meters must form a pointer The rotation shaft passes through the hole. Therefore, a polarizing plate provided in an image display device must also form a through hole. The use and purpose of the polarizing plate are diversified, and depending on the use and purpose, various cases where the polarizing plate must be formed with through holes are set.

However, conventional mechanical methods such as punching (punching) using a punch and a die, or cutting with a drill, etc., may form a through hole when the polarizing plate forms a through hole, and may form cracks near the through hole. . The inclination and cracking of the through-holes impair the polarization ability near the through-holes and cause light leakage. The "light leakage" refers to a phenomenon in which light having a vibration direction parallel to the absorption axis of the polarizer passes through the polarizer.

When laser processing (such as thermal processing) such as CO ₂ laser is used instead of the above-mentioned mechanical method to form a through-hole in a polarizing plate, the through-hole may be inclined and a crack may be formed near the through-hole. Furthermore, in the laser processing, since the portion forming the through hole is heated by the laser, the polarizing ability is easily damaged due to the chemical modification of the polarizer. The so-called chemical modification of polarizers, such as discoloration or dissolution of polarizers. Hereinafter, a portion that impairs a polarizing function due to chemical modification of a polarizer is referred to as a "polarization canceling portion" of a polarizing plate. The larger the polarization elimination portion, the easier it is for the image display device to leak light. According to the research results of the inventors of the present case, it is known that even when processing (for example, ablation) using an excimer laser having a wavelength shorter than that of the CO ₂ laser, the above-mentioned technique is caused by the formation of the through hole problem.

The present invention has been made in view of the circumstances described above, and an object thereof is to provide a polarizing plate capable of suppressing light leakage and an image display device including the polarizing plate.

The polarizing plate of one aspect of the present invention includes a film-shaped polarizer and a plurality of optical films superimposed on the polarizer, wherein the perpendicularity of the hole penetrating the polarizing plate is 0.00 or more and less than 0.32, and the polarization around the hole is eliminated The width of the portion is 0.00 μm or more and less than 32 μm. The "optical film" refers to a film-like member (excluding the polarizer body) constituting a polarizing plate. For example, the meaning of an optical film includes a protective film and a release film.

The number of cracks around the hole may be 0 or more and 3 or less per unit length of 1 mm.

The length of the crack around the hole may be 0 μm or more and less than 50 μm.

At least one optical film of the pair of optical films sandwiching the polarizer may include triethylfluorenyl cellulose.

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

At least one optical film of the pair of optical films sandwiching the polarizer may include polymethyl methacrylate.

A video display device according 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 an image display device including the polarizing plate are provided.

1, 1a, 1b, 1s‧‧‧polarizing plate

3‧‧‧ third protective film

3e 、 3e’‧‧‧first end

5‧‧‧first protective film

7‧‧‧ polarizer

9‧‧‧Second protective film

10‧‧‧ LCD cell

11‧‧‧ Adhesive layer

13‧‧‧ release film

13e 、 13e’‧‧‧Second end

20‧‧‧ LCD panel

21, 21s‧‧‧through hole

23‧‧‧Polarization Elimination Division

25‧‧‧crack

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

60‧‧‧upside polarizer

62‧‧‧ bottom polarizer

64‧‧‧ backlight

A1s, A60, A62‧‧‧ Absorption shaft

1‧‧‧ length of crack

W‧‧‧ Width of Polarization Elimination Section

FIG. 1 is a perspective view of a polarizing plate according to an embodiment of the present invention. Illustration.

FIG. 2 is a schematic cross-sectional view of the polarizer in the direction of the arrow II-II in FIG. 1 along the direction of the arrow (cross-section of the polarizer perpendicular to the surface of the polarizer).

FIG. 3 is an enlarged view of the region III (through the periphery of the hole of the polarizing plate) in the surface of the polarizing plate in FIG. 1.

FIG. 4 is a schematic diagram of the light spots of the excimer laser light and the intensity distribution of the excimer laser along a straight line passing through the center of the excimer laser light point.

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 arrangement of the polarizing plate when the light leakage of the polarizing plate is checked in FIG. 6 (a), and (b) in FIG. 6 is a top view of the configuration shown in (a) of FIG. 6 schematic diagram.

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

As shown in FIG. 1, the polarizing plate 1 according to this embodiment includes a film-shaped polarizer 7 and a plurality of optical films (3, 5, 9, 13) superposed on the polarizer 7. Each of the polarizer 7 and the plurality of optical films (3, 5, 9, 13) is a quadrangle. The plurality of 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, and a second protective film. 9. The third protective film 3 and the release film 13. The polarizing plate 1 also includes an adhesive layer 11 located between the second protective film 9 and the release film 13. One surface of the polarizer 7 is overlapped with the first protective film 5, and the other surface of the polarizer 7 is overlapped with the second protective film 9. A third protective film 3 is stacked on the first protective film 5. That is, the first protective film 5 is located between the polarizer 7 and the third protective film 3. The release film 13 is laminated on the second protective film 9 via the adhesive layer 11. In other words, the second protective film 9 is located between the polarizer 7 and the adhesive layer 11.

One surface (first surface) of the polarizing plate 1 is composed of a third protective film 3. The other surface (second surface) of the polarizing plate 1 is composed of a release film 13. The cross section of the polarizing plate 1 shown in FIG. 2 is perpendicular to the polarizing plate 7 and each optical film (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 light receiving surface of the polarizing plate 1.

A hole (through-hole 21) is formed in the polarizing plate 1 and penetrates the polarizing plate 1. The through-hole 21 is substantially perpendicular to the surface (XY plane) of the polarizing plate 1 and is substantially parallel to the lamination direction (Z-axis direction) of the polarizer 7 and the plurality of optical films (3, 5, 9, 13). The shape of the through hole 21 in a direction (XY plane direction) parallel to the surface of the polarizing plate 1 is, for example, a circle as shown in FIG. 3. The inner wall of the through hole 21 may be non-smooth.

The verticality of the through hole 21 is 0.00 or more and less than 0.32. The verticality will be described below based on FIG. 2.

The cross section of the polarizing plate 1 shown in FIG. 2 is perpendicular to the surface of the polarizing plate 1 and includes the central axis of the circular through hole 21. Will be located in polarized light An end portion of the first optical film (for example, the third protective film 3) on one side surface (first surface) of the plate 1 and corresponding to the edge of the through hole 21 is defined as the first end portion 3e. An end portion of a second optical film (for example, a release film 13) located on the other side surface (second surface) of the polarizing plate 1 and corresponding to the edge of the through hole 21 is defined as a second end portion 13e. Either the first end portion 3 e or the second end portion 13 e is located on the same cross section of the surface of the vertical polarizing plate 1. The distance between the first end portion 3e and the second end portion 13e parallel to the surface direction (XY plane direction) of the polarizing plate 1 is defined as a. The thickness (for example, the average value of the thickness) of the polarizing plate 1 is defined as b. Verticality is defined as a / b. The verticality can also be defined as a '/ b. a 'is a distance between the first end portion 3e' and the second end portion 13e 'parallel to the surface direction of the polarizing plate 1. The first end portion 3e 'refers to the other first end portion located on the opposite side of the first end portion 3e. The second end portion 13e 'refers to the other second end portion on the opposite side of the second end portion 13e. a / b may be equal to a '/ b. a / b may not be equal to a '/ b. When a / b is different from a '/ b, a / b and a' / b are both 0.00 or more and less than 0.32. Within the limits of the above definition, a and b can be measured at any cross section of the polarizing plate 1, and a / b can be calculated from the respective measured values of a and b. When the perpendicularity a / b is calculated on an arbitrary complex cross section of the polarizing plate 1, the maximum value of the calculated complex perpendicularity a / b may be 0.00 or more and less than 0.32. a, a ', b, and b' may be measured by, for example, using an optical microscope and observing the cross section of the polarizing plate 1.

Since the perpendicularity a / b of the through hole 21 does not reach 0.32, light leakage is suppressed. When the perpendicularity a / b of the through-hole 21 is 0.32 or more, the cross-section (end surface) of the polarizer 7 exposed in the through-hole 21 becomes prominent due to light refraction or the like. The verticality a / b of the through hole 21 may be 0.00 Above 0.30 or less, 0.00 or more and 0.28 or less, 0.00 or more and 0.27 or less, 0.05 or more and 0.30 or less, 0.05 or more and 0.28 or less or 0.05 or more and 0.27 or less. The smaller the perpendicularity a / b, the easier it is to suppress light leakage. Therefore, a 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 through-hole 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 is, 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 or a 'between the first end portion and the second end portion may be any value as long as a / b is 0.00 or more and less than the 0.32 limit.

When the openings at both ends of the through-hole 21 are a pair of concentric circles, the perpendicularity may be defined as follows. The inner diameter (diameter) of one end (opening portion) of the through hole 21 is defined as d1. The inner diameter (diameter) of the other end (opening portion) of the through hole 21 is defined as d2. At this time, the verticality of the through hole 21 can be defined as an absolute value of (d1-d2) / 2b. This definition does not contradict the above definition (a / b). That is, the absolute value of (d1-d2) / 2 is equal to a or a '. d1 and d2 may be measured by observing both surfaces of the polarizing plate 1 using an optical microscope, for example.

In some cases, around the through-hole 21, a polarized light eliminating portion 23 is formed. The polarized light eliminating portion 23 is formed during the formation of the through hole 21 due to chemical modification of the polarizer 7 or the optical films (3, 5, 9, 13) overlapping the polarizer 7. The polarization eliminating section 23 may be formed along the first surface (for example, the surface of the third protective film 3). The polarization eliminating section 23 may be formed along a second surface (for example, the surface of the release film 13) on the opposite side of the first surface. Partial The light eliminating section 23 may be continuously or discontinuously in a direction (Z-axis direction) perpendicular to the surface of the polarizing plate 1. In other words, the polarization eliminating section 23 may have a depth from the surface of the polarizing plate 1. In other words, the polarization-removing portion 23 may be a three-dimensional distribution. For example, the polarization-removing portion 23 may be a cylindrical portion surrounding the entire through-hole 21. The polarization elimination unit 23 is one of the causes of light leakage. The light leakage of the polarizing elimination section 23 is caused by a change in the chemical composition of the polarizer 7 or the optical films (3, 5, 9, 13) overlapping the polarizer 7. For example, due to the disorder of the alignment of the polyvinyl alcohol or the pigment molecules (the iodine-containing compound) constituting the polarizer 7, light leakage from the polarized light canceling section 23 is caused.

The width W of the polarization removing section 23 around the through hole 21 of the polarizing plate 1 is 0.00 μm or more and less than 32 μm. As shown in FIG. 3, the width W of the polarization removing section 23 refers to the width of the polarization removing section 23 in a direction parallel to the surface of the polarizing plate 1. Here, the "surface of the polarizing plate 1" may be the first surface (for example, the surface of the third protective film 3) or the second surface (for example, the surface of the release film 13) opposite to the first surface. The width W of the polarization canceling portion 23 viewed in a direction perpendicular to the first surface of the polarizing plate 1 is 0.00 μm or more and not more than 32 μm, and the width of the polarization canceling portion 23 viewed in a direction perpendicular to the second surface of the polarizing plate 1. W may be 0.00 μm or more and less than 32 μm. The width W of the polarization eliminating section 23 may be the width of the polarization eliminating section 23 in the XY plane direction. Since the polarizing plate 1 is slightly transparent, the polarization removing section 23 located on the second surface side (the surface side of the release film 13) can be viewed from the first surface side (the surface side of the third protective film 3). That is, the polarized light elimination portion 23 viewed 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). Further, the polarization eliminating section 23 located inside the polarizing plate 1 can be viewed from the first surface side or the second surface side. The polarized light elimination portion 23 located on the first surface side (the surface side of the third protective film 3) can be viewed from the second surface side (the surface side of the release film 13). That is, the polarized light eliminating portion 23 viewed on the second surface side (the surface side of the release film 13) is not necessarily formed in 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 (Z-axis direction), the three-dimensionally distributed polarizing canceling portions 23 can be seen in an overlapping state. That is, the polarized light eliminating portions 23 that are distributed three-dimensionally around the through-hole 21 can be observed as a two-dimensional orthographic projection (for example, a ring surrounding the through-hole 21) of the surface (XY plane) of the polarizing plate 1.

When the width W of the polarization removing section 23 is less than 32 μm, light leakage can be suppressed. In the case where the width W of the polarization elimination section 23 is 32 μm or more, light leakage from the polarization elimination section 23 becomes significant. The width W of the polarization removing section 23 of the polarizing plate 1 may be 0.00 μm or more and less than 20 μm, 0.00 μm or more and less than 19 μm, or 0.00 μm or more and 18 μm. The smaller the width W of the polarization eliminating section 23 is, the easier it is to suppress light leakage. Therefore, it is desirable that the width W of the polarization-removing portion 23 is 0.00 μm. That is, the non-polarized-light eliminating section 23 is most preferable. The width W of the polarization removing section 23 around the through hole 21 may be not fixed as long as it is within a range of 0.00 μm or more and less than 32 μm. In the case where the width W of the polarization removing section 23 is not constant, the maximum value of the width W of the polarization removing section 23 is less than 32 μm.

A crack 25 may be formed around the through hole 21. The crack 25 may be formed along the first surface (the surface of the third protective film 3). The crack 25 can also run along the second surface (release film 13) on the opposite side of the first surface. 的 surface) formation. The cracks 25 may be formed continuously or discontinuously in a direction (Z-axis direction) perpendicular to the surface of the polarizing plate 1. That is, the crack 25 may have a depth from the surface of the polarizing plate 1. In other words, the cracks 25 may be a three-dimensional distribution.

The number of cracks 25 around the through hole 21 of the polarizing plate 1 may be 0 or more and 3 or less per unit length of 1 mm. The “unit length of 1 mm” refers to a straight line or curve parallel to the edge of the through hole 21 and having a length of 1 mm. For example, when the shape of the through hole 21 is round, the unit length refers to an arc that is parallel to the circular edge of the through hole 21. The “number of cracks 25” refers to the number of cracks 25 that intersect with a unit length of 1 mm in the cracks 25 viewed in a direction (Z-axis direction) perpendicular to the surface of the polarizing plate 1. The cracks 25 observed on the first surface (for example, the surface of the third protective film 3) can be counted. It is also possible to count the cracks 25 observed on the second surface (the surface of the release film 13) opposite to the first surface. The number of cracks 25 observed on the first surface of the polarizing plate 1 is 0 to 3 per unit length of 1 mm, and the number of cracks 25 observed on the second surface of the polarizing plate 1 is 1 mm per unit length. 0 to 3 may be sufficient. Since the polarizing plate 1 is slightly transparent, the cracks 25 located on the second surface side (the surface of the release film 13) of the polarizing plate 1 can be viewed from the first surface side (the surface of the third protective film 3). That is, the crack 25 observed on the first surface side (the surface of the third protective film 3) is not necessarily formed in the first optical film (third protective film 3). The cracks 25 located inside the polarizing plate 1 can be viewed from the first surface side or the second surface side. The crack 25 on the first surface side (the surface side of the third protective film 3) can be viewed from the second surface side (the surface side of the release film 13). That is, the crack 25 observed on the second surface side (the surface side of the release film 13) does not necessarily form on the second surface. Optical film (release film 13). Since the polarizing plate 1 is slightly transparent, when the surface of the polarizing plate 1 is observed in a direction perpendicular to the surface of the polarizing plate 1 (Z-axis direction), cracks 25 that are three-dimensionally distributed in an overlapping state can be seen. That is, the three-dimensionally distributed cracks 25 can be observed as a two-dimensional orthographic projection on the surface (XY plane) of the polarizing plate 1. A plurality of cracks 25 are overlapped in a direction (Z-axis direction) perpendicular to the surface of the polarizing plate 1, and one crack 25 is seen on the surface of the polarizing plate 1. That is, a plurality of cracks 25 overlapping in a direction (Z-axis direction) perpendicular to the surface of the polarizing plate 1 can be counted as one crack 25 on the surface of the polarizing plate 1.

When the number of cracks 25 is 3 or less, it is easier to suppress light leakage. The length 1 of the crack 25 may be 0 μm or more and less than 50 μm. The length 1 of the crack 25 is the length of the crack 25 observed in a direction (Z-axis direction) perpendicular to the surface of the polarizing plate 1 and is the shortest distance between the end of the crack 25 and the edge of the through hole 21 . The length 1 of the crack 25 can be measured on the first surface (for example, the surface of the third protective film 3). The length 1 of the crack 25 can also be measured on the second surface (the surface of the release film 13) opposite to the first surface. The length 1 of the crack 25 measured on the first surface of the polarizing plate 1 may be 0 μm or more and less than 50 μm, and the length 1 of the crack 25 measured on the second surface of the polarizing plate 1 may be 0 μm or more and less than 50 μm. In the case where the length 1 of the crack 25 is less than 50 μm, it is easier to suppress the light leakage that can be recognized. The smaller the number of cracks 25 and the shorter the cracks, the easier it is to suppress light leakage. In addition, the smaller the number of cracks 25 and the shorter the cracks, the higher the mechanical strength of the polarizing plate 1 and the easier it is to suppress the damage of the polarizing plate 1 during the manufacturing process of the image display device. Therefore, no crack 25 is ideal.

The diameter d (inner diameter d1 or d2) of the through hole 21 may be, for example, It is 50 to 5000 μm.

The manufacturing method of the polarizing plate 1 according to this embodiment includes the steps of forming a laminated body by overlapping a film-shaped polarizer with a plurality of optical films; and irradiating the laminated body with an excimer laser pulse wave to form the laminated body. The step of penetrating the hole (through hole 21); where the output of the excimer laser is less than 20W; the intensity of the outer circumference of the excimer laser light spot is greater than 80% of the maximum value of the intensity of the light spot; Greater than 50 μm; the repetition frequency of excimer lasers does not reach 1000 Hz.

In this embodiment, a through-hole 21 is formed in a portion of the laminated body that is irradiated with excimer laser light. Each step is described in detail below.

The laminated body can be produced by repeatedly bonding the polarizer 7 and the optical films (3, 5, 9, 13) or bonding the optical films to each other. The adhesive layer 11 can be formed by, for example, applying a pressure-sensitive adhesive on the surface of the second protective film 9.

The excimer laser may 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 a CO ₂ laser is 9.4 μm or 10.6 μm. When a short-wavelength excimer laser is irradiated to the multilayer body, the polymers constituting the polarizer 7 and each optical film (3, 5, 9, 13) are easily decomposed and sublimated instantaneously, and the multilayer layer accompanied by the excimer laser radiation is suppressed Body heating. Therefore, it is easy to form the through hole 21 having a small perpendicularity instantaneously, and it is also possible to suppress chemical deterioration of the polarizer 7 and each optical film (3, 5, 9, 13) due to heat. On the other hand, when the multilayer body is irradiated with a laser with a long wavelength, the temperature of the portion irradiated with the laser is likely to rise, and it is difficult to cause the polymer constituting the polarizer 7 and each optical film (3, 5, 9, 13) Decomposition and sublimation. That is, a through-hole is formed by melting and deforming a portion heated by laser irradiation. Therefore, if a laser with a longer wavelength than the excimer laser is used, it is difficult to control the verticality of the through hole, and due to the chemical modification of the polarizer 7 and each optical film (3, 5, 9, 13), It is easy to form a polarization-removing portion.

The output of the excimer laser is more than 1W and less than 20W. In the case where the output of the excimer laser is 20 W or more, a crack 25 is easily formed around the through-hole 21, and the width W of the polarization-removing portion 23 is easily increased. The output of an excimer laser can be 5W or more and 8W or less.

As shown in Fig. 4, the spot LS of the excimer laser is circular. The intensity distribution ID of the light spot LS of the excimer laser along a straight line passing through the center Lc of the light spot LS of the excimer laser is a high hat type. In other words, the light spot LS is a cross section of the excimer laser perpendicular to the traveling direction of the excimer laser. The verticality of the through-holes formed using a high-hat-type excimer laser is smaller than the verticality of the through-holes formed using an excimer laser with a Gaussian intensity distribution. The intensity ILe of the outer peripheral portion Le of the excimer laser light spot LS is greater than 80% of the maximum value ILc of the intensity of the light spot LS and less than 100% of ILc. In other words, (ILe / ILc) × 100 is greater than 80% and less than 100%. In other words, {(ILc-ILe) / ILc} × 100 is from 0% to 20%. In other words, ILc is the average of the intensities of the flat portions (tops) in 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, verticality a / b tends to increase. In other words, when (ILe / ILc) × 100 is 80% or less, the verticality a / b tends to increase. In other words, when {(ILc-ILe) / ILc} × 100 is 20% or more, the verticality a / b tends to increase. ILe can be above 90% and below 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 is, for example, W / m ² .

In the case of forming the through hole 21 having a diameter approximately the same as the condensing diameter of the excimer laser, the condensing diameter of the excimer laser is greater than 50 μm and less than 2000 μm. In the case where the condensing diameter of the excimer laser is less than 50 μm, the perpendicularity a / b tends to be large. The so-called condensing diameter of the excimer laser means the diameter of the light spot LS of the excimer laser. The condensing diameter of the excimer laser may be 600 μm or more and 1000 μm or less. The condensing diameter of the excimer laser may be different from the diameter d of the through hole 21. For example, by scanning a designated area on the surface of the multilayer body with an excimer laser with a small condensing diameter, a through-hole 21 having a diameter d larger than the condensing diameter of the excimer laser may be formed.

The repetition frequency of an excimer laser is above 10 Hz and less than 1000 Hz. In the case where the repetition frequency of the excimer laser is above 1000Hz, The cracks 25 are easily formed, and the polarization canceling portion 23 is also easily formed. The repetition frequency of excimer laser can be 100Hz to 500Hz.

The inner diameter of the through hole 21 on the surface side (for example, the third protective film 3 side) irradiated by the excimer laser tends to be larger than the inner diameter of the through hole 21 on the opposite side (for example, the release film 13 side).

The polarizer 7 may be a film-like polyvinyl alcohol-based resin produced by steps such as stretching, dyeing, and crosslinking. The details of the polarizer 7 are as follows.

For example, the film-shaped polyvinyl alcohol-based resin is first stretched in one or two axial directions. The polarizer 7 extended in one axis direction tends to have a high dichroic ratio. After stretching, a 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. Polyvinyl alcohol resin can also be washed before dyeing. By washing with water, dirt and agglomerates can be removed from the surface of the polyvinyl alcohol resin. Furthermore, as a result of the swelling 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 the treatment with the crosslinking agent, the polyvinyl alcohol-based resin is washed with water and then dried. Through the above procedure, a polarizer 7 is obtained. A polyvinyl alcohol-based resin can be obtained by saponifying a polyvinyl acetate-based resin. Polyvinyl acetate-based resins, such as the individual polymer of vinyl acetate, polyvinyl acetate, or copolymers of vinyl acetate and other monomers copolymerizable therewith (for example, ethylene-vinyl acetate copolymers). Other monomers copolymerizable with vinyl acetate, in addition to ethylene, unsaturated carboxylic acids, olefins, ethyl Allyl ethers, unsaturated sulfonic acids, or acrylamides having ammonium groups. Polyvinyl alcohol resin can be modified by aldehydes. The modified polyvinyl alcohol-based resin is, for example, 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 product of polyvinyl alcohol or a dehydrochlorinated product of polyvinyl chloride. Staining can be performed before stretching or in a dyeing solution. The length of the polarizer after the extension 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, in the case where the thin polarizer 7 is extended in one axis, a crack 25 is easily formed along the extension direction in the opening step or the slicing step. However, the formation of cracks 25 can be suppressed by the above-mentioned hole-opening step using an excimer laser.

The first protective film 5 and the second protective film 9 may be thermoplastic resins having translucency, and they may also be optically transparent thermoplastic resins. Resins constituting the first protective film 5 and the second protective film 9 include, for example, a chain polyolefin resin, a cyclic olefin polymer resin (COP resin), a cellulose ester resin, a polyester resin, and a polycarbonate. Based resin, (meth) acrylic based resin, polystyrene based resin, or a mixture or copolymer thereof. The composition of the first protective film 5 may be exactly the same as that of the second protective film 9, and the composition of the first protective film 5 may be different from that of the second protective film 9.

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

Cyclic olefin polymer resin (cyclic polyolefin tree Lipids), for example, ring-opened (co) polymers of cyclic olefins, or addition polymers of cyclic olefins. The cyclic olefin polymer-based 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 copolymer obtained by modifying the polymer with an unsaturated carboxylic acid or a derivative thereof, or a hydrogenated product thereof. The cyclic olefin polymer-based resin may be a norbornene-based resin using a norbornene-based monomer such as norbornene or a polycyclic norbornene-based monomer.

The cellulose ester-based resin may be, for example, cellulose triacetate (triethyl cellulose (TAC)), cellulose diacetate, cellulose tripropionate, or cellulose dipropionate. These copolymers can also be used. A cellulose ester resin in which a part of the hydroxyl group is modified with another substituent may also be used.

Polyester resins other than cellulose ester resins can 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 a derivative thereof may be a dicarboxylic acid or a derivative thereof. Polyvalent carboxylic acids or derivatives thereof, such as terephthalic acid, isophthalic acid, dimethyl terephthalate, or dimethyl naphthalate. The polyvalent alcohol may be, for example, a diol. Polyvalent alcohols are, for example, ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol or cyclohexanedimethanol.

The polyester-based resin may be, for example, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, or polytrimethylene terephthalate. , Poly (trimethylene naphthalate), poly (cyclohexanedimethyl terephthalate), or poly (cyclonaphthalene dinaphthalate).

Polycarbonate resin is a polymer in which a polymerized unit (monomer) is bonded via a carbonate group. The polycarbonate-based resin may be a modified polycarbonate having a modified polymer skeleton or a copolymerized polycarbonate.

The (meth) acrylic resin may be, for example, poly (meth) acrylate (such as polymethyl methacrylate (PMMA)); methyl methacrylate- (meth) acrylic copolymer; methyl methacrylate -(Meth) acrylate copolymer; methyl methacrylate-acrylate- (meth) acrylic copolymer; methyl (meth) acrylate-styrene copolymer (such as MS resin); methyl methacrylate Copolymers with compounds having an alicyclic hydrocarbon group (for example, methyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate-norbornyl (meth) acrylate copolymer, etc.).

At least one optical film of a pair of optical films (the first protective film 5 and the second protective film 9) sandwiching the polarizer 7 may include triethylfluorene cellulose (TAC). At least one optical film 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 (COP resin). At least one optical film 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 triethylfluorene cellulose. One of the pair of optical films (the first protective film 5 and the second protective film 9) sandwiching the polarizer 7 may include triethyl cellulose, and the other of the pair of optical films sandwiching the polarizer 7 The film may include a cyclic olefin polymer. One of the pair of optical films (the first protective film 5 and the second protective film 9) sandwiching the polarizer 7 may include triethyl cellulose, and the other of the pair of optical films sandwiching the polarizer 7 The film may include 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-based resin, and the other of the pair of optical films sandwiching the polarizer 7 One film may contain polymethyl methacrylate. In the case where an optical film composed of TAC, COP resin or PMMA contacts the polarizer 7, if the conventional processing method is used, the perpendicularity a / b of the through-hole 21 is reduced, and the formation of the polarization-removing portion 23 and the crack 25 is suppressed. Difficulties. However, by the above-mentioned hole-opening step using an excimer laser, the perpendicularity a / b of the through-hole 21 is reduced, and the formation of the polarization elimination section 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) may 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) may be 160 to 180 ° C. In the case where the optical film (3, 5, 9, or 13) is composed of a cyclic olefin polymer-based resin (COP-based resin), the glass transition temperature Tg of the optical film (3, 5, 9, or 13) may be 126 to 136 ° C. In the case where the optical film (3, 5, 9, or 13) is composed of polymethyl methacrylate (PMMA), the glass transition temperature Tg of each optical film (3, 5, 9, or 13) may be 108 to 136 ° C. . When the glass transition temperature Tg of the polarizer 7 and each optical film (3, 5, 9, 13) is 100 ° C or higher, the polarizer 1 has good heat resistance, and it is easy to suppress the heat caused by the excimer laser irradiation. Deformation of the polarizing plate 1.

The first protective film 5 or the second protective film 9 may further include at least one group selected from the group consisting of a lubricant, a plasticizer, a dispersant, a heat stabilizer, an ultraviolet absorber, an infrared absorber, an antistatic agent and an antioxidant One Additives.

The thickness of the first protective film 5 may be, 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 may be, 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, a film made of the thermoplastic resin is stretched, and a liquid crystal layer or the like is formed on the film to obtain a retardation film having an arbitrary retardation value.

The first protective film 5 can be bonded to the polarizer 7 through an adhesive layer. The second protective film 9 may be bonded to the polarizer 7 through 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 resins are resins that are hardened by irradiation with active energy rays. The active energy rays are, for example, ultraviolet rays, visible rays, 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 kind of resin or may include a plurality of kinds of resins. For example, the active energy ray-curable resin may include a cationically polymerizable curable compound or a radically polymerizable curable compound. The active energy ray-curable resin may include a cationic polymerization initiator or a radical polymerization initiator for initiating a curing reaction of the curable compound.

Cationically polymerizable hardening compound, for example, An epoxy-based compound (a compound having at least one epoxy group in the molecule) or an oxetane-based compound (a compound having at least one oxetane ring in the molecule). The radically polymerizable sclerosing compound may be, for example, a (meth) acrylic compound (a compound having at least one (meth) acryloxy group in the molecule). The radically polymerizable sclerosing compound may also be a radically polymerizable vinyl compound having a double bond.

Active energy ray hardening resin, which may include a cationic polymerization accelerator, an ion trapping agent, an antioxidant, a chain transfer agent, an adhesion imparting agent, a thermoplastic resin, a filler, a flow modifier, a plasticizer, an antifoaming agent, and an antistatic agent as required Agent, leveling agent, or solvent.

The adhesive layer 11 may include a pressure-sensitive adhesive such as an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a polysiloxane-based pressure-sensitive adhesive, or an urethane-based pressure-sensitive adhesive. Agent. 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 resins listed as the first protective film 5 or the second protective film 9. The thickness of the third protective film 3 may be, for example, 5 μm or more and 200 μm or less.

The resin constituting the release film 13 may be the same as the resins listed as the first protective film 5 or the second protective film 9. The thickness of the release film 13 may be, for example, 5 μm or more and 200 μm or less.

The image display device of the present invention 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 according to this embodiment includes a liquid crystal cell 10, A polarizing plate 1 a (first polarizing plate) on one surface (first surface) of the liquid crystal cell 10 and a polarizing plate 1 b (second polarizing plate) overlapping the other surface (second surface) of the liquid crystal cell 10. The polarizing plates 1 a and 1 b as shown in FIG. 5 are the same as the polarizing plate 1 shown in FIGS. 1 and 2 except that they do not include a release film 13 and a third protective film 3. The polarizing plate 1 a (first polarizing plate) is attached to the first surface of the liquid crystal cell 10 through 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 sheet 7 overlapping the second protective film 9, and overlapping First protective film 5 on the polarizer 7. The other polarizing plate 1 b (second polarizing plate) is attached to the second surface of the liquid crystal cell 10 through the adhesive layer 11. The other 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 sheet 7 overlapping the second protective film 9. A first protective film 5 superposed on the polarizer 7. The liquid crystal cell 10 and the pair of polarizing plates 1 a and 1 b constitute a liquid crystal panel 20. The liquid crystal panel 20 and other components of the backlight (surface light source device) constitute a liquid crystal display device 30. Other components of the backlight are omitted in FIG. 5.

As mentioned above, although one embodiment of this invention was described, this invention is not limited to the said 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 overall shape of the 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 quadrangle. For example, the polarizing plate may be circular, oval, or irregular. The outer edge of the polarizing plate may be composed of only straight lines (plural sides). Here, the outer edge of the polarizing plate refers to Figures 1 to 3 The outer edge of the polarizing plate as seen in the Z direction (direction perpendicular to the surface of the polarizing plate 1). The outer edge of the polarizing plate may consist of only a curved line depending on the application. The shapes of the polarizer 7 and each of the optical films (3, 5, 9, 13) may be various shapes depending on the application.

The shape of the through hole in a direction (direction of the XY plane) parallel to the surface of the polarizing plate 1 can be various shapes depending on the application. The shape of the through hole may be a shape other than a circle. For example, the shape of the through hole may be elliptical, polygonal, or irregular. A plurality of through holes 21 may be formed in the polarizing plate 1. A plurality of through holes having the same shape can be formed in the polarizing plate 1. A plurality of through holes having different shapes can be formed in the polarizing plate 1. The position of the through hole in the polarizing plate 1 is not limited. For example, when the polarizing plate is circular, a through hole may be formed in the center (circle center) of the surface of the polarizing plate 1.

There is no limitation on the number of optical films (optical films superimposed on a polarizer) included in the polarizing plate. 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 of the protective films, or may not be provided with the two protective films. For example, any one of the polarizing plates 1a (first polarizing plate) and polarizing plate 1b (second polarizing plate) shown in FIG. 5 or two polarizing plates may not include the first protective film 5 and the second protective film 9 Any of the protective films. Any of the polarizing plates 1a (first polarizing plate) and polarizing plate 1b (second polarizing plate) shown in FIG. 5 or two polarizing plates may not include the two protective films.

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

Optical film in polarizing plate, reflective polarized light Film, film with anti-glare function, film with anti-reflection function on the surface, reflective film, transflective reflective film, viewing angle compensation film, optical compensation layer, touch sensing layer, anti-charge layer, or antifouling layer

A polarizing plate can be further equipped with a hard coating. For example, the polarizing plate 1, the first protective film 5 may be located between the hard coating layer and the polarizing plate 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 triethylfluorenyl cellulose. The surface hardness (pencil hardness) of the hard coat layer may be H or more and 5H or less, or 2H or more and 5H or less. The pencil hardness is based on Japanese Industrial Standards (JIS K5400). The hard coating having a pencil hardness within the above-mentioned range is unlikely to be damaged during the manufacturing process of the polarizing plate 1. However, since the hard coating layer is hard and brittle, and the through hole is formed by a conventional processing method, cracks are easily formed in the hard coating layer. However, by the above-mentioned opening step using an excimer laser, the formation of cracks in the hard coat layer can be suppressed.

The hard coat layer is, for example, a layer made of an acrylic resin film having a fine uneven shape 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, an embossing method) of pressing the coating film onto a roller having an uneven shape may be used. A method of forming a coating film containing no organic fine particles or inorganic fine particles, and then pressing the coating film onto a roller having an uneven shape may also be used.

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. The organic fine particles (resin particles) are, for example, crosslinked polyacrylic particles, methyl methacrylate / styrene copolymer resin particles, crosslinked polystyrene particles, and crosslinked polymethacrylic acid. Methyl ester particles, silicone resin particles, polyfluorene particles, etc.

The binder component for dispersing the organic fine particles or the inorganic fine particles may be selected from materials that have a high hardness (hard coat layer). The binder component may be, for example, an ultraviolet curable resin, a thermosetting resin, an electron beam curable resin, or the like. From the viewpoints of productivity and hardness, it is preferable to use an ultraviolet curable resin as the 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 coating layer is 2 μm or more, sufficient hardness of the hard coating layer can be easily obtained, and the surface of the hard coating layer is more difficult to be injured. When the thickness of the hard coat layer is 30 μm or less, the hard coat layer is less likely to crack, and it is easy to suppress the curl of the polarizing plate due to the hardening and 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 polarization degree P of the polarizer 7 is 99.9 or more. When the conventional polarizer is thin, the single transmittance and the degree of polarization are large, it is easy to find light leakage around the through hole formed in the polarizing plate. However, in the case where the through-hole 21 having a small perpendicularity is formed by the above-mentioned hole-opening step using an excimer laser, light leakage of the polarizing plate 1 provided with the polarizing plate 7 which is thin and has a high transmittance and high polarization can be suppressed.

The moisture content of the laminated body composed of three films, such as the polarizer 7, the first protective film 5, and the second protective film 9, may be 1.0 to 5.0%, 0.5 to 5.5%, or 1.0 to 5.0%. When the water content 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 the polarizing plate 1 shown in Figs. 1 and 2, the inner diameter d1 of the through hole 21 on the third protective film 3 side (first optical film side) is larger than that of the release film 13 side (second optical film side). The inner diameter d2 of the through hole 21, but the inner diameter d1 of the through hole 21 on the third protective film 3 side (the first optical film side) may be smaller than the through hole 21 on the release film 13 side (the second optical film side). The inner diameter d2. In other words, in the polarizing plate 1 shown in FIGS. 1 and 2, the inner diameter d1 of the through hole 21 on the first protective film 5 side is larger than the inner diameter d2 of the through hole 21 on the second protective film 9 side, but the first The inner diameter d1 of the through hole 21 on the protective film 5 side may be smaller than the inner diameter d2 of the through hole 21 on the second protective film 9 side.

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 can be peeled off and removed from the polarizing plate 1 during the manufacturing process of the image display device. That is, the third protective film 3 may be a temporary protective film. The release film 13 may be peeled and removed from the polarizing plate 1 in the manufacturing process of the image display device.

[Example]

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

(Example 1)

As shown in FIG. 1, a plate-shaped laminated body composed of a polarizer 7 and an optical film (3, 5, 9, 13) was formed. The laminated body includes a release film 13, an adhesive layer 11 overlapping the release film 13, a second protective film 9 overlapping the adhesive layer 11, a polarizer 7 overlapping the second protective film 9, and a first polarizer 7 overlapping the polarizer 7. A protective film 5 and a third protective film 3 overlapping the first protective film 5. As the polarizer 7, a stretched and dyed film-like polyvinyl alcohol was used. As the first guarantee For the protective film 5, a triethyl cellulose (TAC) film (25KCHCN-TC made by letterpress printing) was used. As the second protective film 9, a film made of a cyclic olefin polymer-based resin (COP-based resin) (ZF14-023-1350, manufactured by Zeon Corporation) was used. As the third protective film 3, an adhesive-attached PET protective film (AS3-304 manufactured by Fujimori Industry Co., Ltd.) was used. As the release film 13, PET (SP-PLR382050 manufactured by LINTEC) was used. The release film 13 has a thickness of 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 is 32 μm. The thickness of the third protective film 3 is 60 μm. The thickness of the entire laminated body (the thickness corresponding to the thickness b of the polarizing plate 1) was 185 μm. The overall longitudinal width of the laminated body was 110 mm. The overall lateral width of the laminated body was 60 mm.

A pulse wave of an excimer laser is irradiated to the surface on the third protective film 3 side of the multilayer body, and a through-hole 21 as shown in FIGS. 1 and 2 is formed in the multilayer body. Through the above steps, the polarizing plate 1 of Example 1 was obtained. As the excimer laser, an ArF laser with an oscillation wavelength of 193 nm was used. As an excimer laser oscillator, MLI series (1000 type) manufactured by Mlase was used. The output of the excimer laser is set to 5W. As shown in Fig. 4, the spot LS of the excimer laser is circular. The intensity of the outer peripheral portion Le of the excimer laser light spot LS is denoted by ILe, and the maximum value of the intensity of the light spot LS (the intensity of the flat top) is denoted by 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 was set to 1000 μm. The repetition frequency of the excimer laser is set to 100 Hz.

As shown in FIG. 3, the shape of the through hole 21 in a direction (XY plane direction) parallel to the surface of the polarizing plate 1 is circular. The opening on the third protective film 3 side of the through hole 21 and the opening on the release film 13 side of the through hole 21 are a pair of concentric circles. The inner diameter d1 (diameter) of the through-hole 21 (circular opening) on the third protective film 3 side was measured. The inner diameter d2 (diameter) of the through hole 21 (circular opening) on the release film 13 side was also measured. The inner diameter d1 of the through-hole 21 on the third protective film 3 side irradiated by the excimer laser is larger than the inner diameter d2 of the through-hole 21 on the opposite side (the release film 13 side). The measured values of d1 and d2 are close to the condensing diameter of the excimer laser. From the measured values of d1 and d2, the perpendicularity (d1-d2) / 2b of the through-hole 21 is calculated. The perpendicularity of Example 1 was 0.06.

The periphery of the through-hole 21 on the third protective film 3 side irradiated with excimer laser light was observed with an optical microscope. Based on this observation, among the cracks formed around the through hole 21, it was attempted to count the number of cracks having a length 1 of less than 50 μm and the number of cracks having a length 1 of 50 μm or more. The definition of the number of cracks is the same as that in the above embodiment. The definition of the crack length 1 is the same as that of the above embodiment. As a result of observation, around the through-hole 21 of the polarizing plate 1 of Example 1, there were no cracks having a length 1 of less than 50 μm. Further, there were no cracks around the through hole 21 of the polarizing plate 1 of Example 1 with a length 1 of 50 μm or more.

Based on the above observation using an optical microscope, an attempt was made to measure the width W of the polarization-removing portion 23 (color-changing portion) around the through-hole 21. However, there is no polarized light eliminating portion 23 around the through hole 21 of the polarizing plate 1.

As shown in (a) and (b) of Figure 6, the backlight 64 (surface light source) The entire surface is covered with a 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 faced to the lower polarizing plate 62. The polarizing plate 1s of Example 1 is superposed on the lower polarizing plate 62, so that the absorption axis A1s of the polarizing plate 1s of Example 1 is perpendicular to the absorption axis A62 of the lower polarizing plate 62. The upper polarizing plate 60 is superposed on the polarizing plate 1s of Example 1, and the absorption axis A60 of the upper polarizing plate 60 is arranged 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.

The polarizing plate 1s of Example 1 was turned on with the backlight 64 in the state arranged as described above, and the polarizing plate 1s of Example 1 was visually observed. The observation results showed that there was no light leakage around the through hole 21s of the polarizing plate 1s.

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

In Example 6, as the excimer laser, a KrF laser (oscillation wavelength: 248 nm) was used in place of the ArF laser.

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

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

Except for the above, in the same manner as in Example 1, an excimer laser was used to form a through-hole in the laminate, and each of the polarizing plates of Examples 2 to 7 and Comparative Examples 1 to 4 was obtained.

Using the same method as in Example 1, the perpendicularity of the through-holes of each of the polarizing plates of Examples 2 to 7 and Comparative Examples 1 to 4 was determined. The perpendicularities 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, the surfaces of the third protective film irradiated with excimer laser light were observed in Examples 2 to 7 and Comparative Examples 1 to 4, respectively, and the number of cracks formed around the through hole was counted and measured. The length of each 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 formed around the through hole is 3 or less. In any embodiment, the length of the crack formed around the through hole is less than 50 μm.

Using the same method as in Example 1, the surfaces of the third protective film side were observed in Examples 2 to 7 and Comparative Examples 1 to 4, respectively, and the width of the polarization-removing portion (discolored portion) around the through hole was measured. In Examples 2 to 7 and Comparative Examples 1 to 4, the width W of the polarization-removing portion (color changing portion) is shown in Table 1 below. In any embodiment, the width of the polarization-removing portion (color-changing portion) is less than 32 μm.

Using the same method as in Example 1, the leakage of light around the through holes of the polarizing plate was examined in Examples 2 to 7 and Comparative Examples 1 to 4, respectively. The test results are shown in Table 1 below.

[Industrial availability]

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

Claims (9)

A polarizing plate includes: a film-shaped polarizing plate and a plurality of optical films superposed on the polarizing plate; a perpendicularity of a hole penetrating the polarizing plate is 0.00 or more and less than 0.32; and a width of a polarizing eliminating portion around the hole It is 0.00 μm or more and less than 32 μm. The polarizing plate according to item 1 of the scope of patent application, wherein the number of cracks around the hole is 0 to 3 per unit length of 1 mm. The polarizing plate according to item 1 or 2 of the scope of the patent application, wherein the length of the crack around the hole 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 optical film of the pair of optical films sandwiching the polarizer includes triethylfluorene-based cellulose. The polarizing plate according to item 1 or 2 of the scope of patent application, wherein at least one optical film of the pair of optical films sandwiching the polarizer includes a cyclic olefin polymer. The polarizing plate according to item 1 or 2 of the scope of patent application, wherein at least one optical film of the pair of optical films sandwiching the polarizer includes a (meth) acrylic resin. The polarizing plate according to item 1 or 2 of the scope of the patent application, wherein the aforementioned polarizer includes a polyvinyl alcohol-based resin, and at least one of the aforementioned optical films includes a thermoplastic resin. The polarizing plate according to item 1 or 2 of the scope of patent application, which is used in an image display device. An image display device includes the polarizing plate according to any one of claims 1 to 8 of the scope of patent application.