TW202036053A - Polarization plate - Google Patents

Abstract

Provided is a polarization plate that produces minute displacement in a through-hole portion even in a high-temperature environment. The polarization plate according to the present invention has: a polarizer; a protective layer that is disposed at least on one side of the polarizer; and an adhesive agent layer. The polarization plate has a through-hole formed at an end or in the vicinity thereof, and, after the polarization plate is subjected to a heating test at 85 DEG C for 120 hours while the polarization plate is kept bonded to a glass plate by means of the adhesive agent layer, the amount of displacement of the polarization plate in the through-hole portion is at most 300 [mu]m.

Description

Polarizer

The present invention relates to a polarizing plate. More specifically, the present invention relates to a polarizing plate having an adhesive layer and formed with through holes.

In image display devices such as mobile phones and notebook personal computers, polarizing plates are widely used in order to realize image display and/or improve the image display performance. In recent years, due to the rapid spread of smart phones and touch panel-type information processing devices, image display devices equipped with cameras have gradually been widely used. In response to this situation, polarizing plates with through holes at positions corresponding to the camera are gradually being widely used. Regarding the polarizing plate having such a through hole, there are various review items for the through hole or its vicinity.

Prior art literature Patent literature Patent Document 1: International Publication No. 2017/047510

Problems to be solved by the invention The present invention was made in order to solve the above-mentioned conventional problems, and its main purpose is to provide a polarizing plate in which the deviation in the through hole portion is small even in a high temperature environment.

Means for Solving the Problem The polarizing plate of the present invention has a polarizing member, a protective layer and an adhesive layer arranged on at least one side of the polarizing member. The polarizing plate is formed with through holes at or near the end, and the polarizing plate is attached to the glass plate through the adhesive layer and subjected to a heating test at 85°C and 120 hours. The shift amount of the through hole portion is 300 μm or less. In one embodiment, the distance A (μm) from the outermost part of the adhesive layer in the thickness direction to the center of the polarizer in the thickness direction, the thickness T _pol (μm) of the polarizer, and the potential of the adhesive layer The change value C _psa (μm/hr), the thickness T _psa (μm) of the adhesive layer and the thickness T _pro (μm) of the protective layer satisfy the following relationship: (A×T _pol )×(C _psa ×T _psa )/T _pro =K≦350×10 ² (μm ³ /hr). Another polarizer of the present invention has a polarizer, a protective layer and an adhesive layer disposed on at least one side of the polarizer. The polarizing plate is formed with a through hole at or near the end, and the distance A (μm) from the outermost part of the adhesive layer in the thickness direction to the center of the polarizer in the thickness direction, the thickness T _pol ( μm), the creep value C _psa (μm/hr) of the adhesive layer, the thickness T _psa (μm) of the adhesive layer and the thickness T _pro (μm) of the protective layer satisfy the following relationship: (A×T _pol )×(C _psa ×T _psa )/T _pro =K≦350×10 ² (μm ³ /hr). In one embodiment, the thickness T _pol of the polarizer is 20 μm or less. In one embodiment, the thickness T _pol of the polarizer is 10 μm or less. In one embodiment, the offset of the polarizing plate from the through hole portion is 120 μm or less. In one embodiment, the thickness T _psa of the adhesive layer is 10 μm to 22 μm. In one embodiment, the offset of the polarizing plate is substantially the offset of the adhesive layer. In one embodiment, the through hole is formed in the corner portion. In one embodiment, in a plan view of the polarizer, the distance from the center in the longitudinal direction to the end in the longitudinal direction is L ₁ , and the long side from the center in the longitudinal direction of the polarizer to the center of the through hole The directional distance is L ₂ , the distance from the center of the short side direction of the polarizer to the end of the short side direction is W ₁ , and the short side direction from the center of the short side direction of the polarizer to the center of the through hole When the distance is W ₂ , the aforementioned through holes are formed at positions satisfying 0.85≦L ₂ /L ₁ ≦0.99 and 0.50≦W ₂ /W ₁ ≦0.99. In one embodiment, the polarizer has a rectangular shape, and the absorption axis direction of the polarizer is substantially parallel to the longitudinal direction. In one embodiment, the protective film is arranged only on one side of the polarizer. In one embodiment, the diameter of the through hole is 10 mm or less. In one embodiment, the aspect ratio of the polarizing plate is 1.3 to 2.5. According to another aspect of the present invention, an image display device is provided. The image display device includes an image display unit and the polarizing plate, and the polarizing plate is attached to the image display unit through the adhesive layer.

Invention effect According to the embodiment of the present invention, a polarizing plate can be realized, the polarizing plate has a through hole, and the deviation of the through hole portion of the polarizing plate is small even in a high temperature environment.

The following describes specific embodiments of the present invention with reference to the drawings, but the present invention is not limited by these embodiments. In addition, the drawings are schematically shown for ease of viewing, and the ratios of length, width, thickness, etc., and angles in the drawings are different from actual ones.

A. The overall composition of the polarizer 1 is a schematic plan view illustrating the formation position of a through hole in a polarizing plate according to an embodiment of the present invention; FIG. 2 is a schematic cross-sectional view taken along the line II-II of the polarizing plate shown on the left side of FIG. 1. The polarizing plate 100 of the schematic example has: a polarizing member 11, a protective layer (hereinafter sometimes referred to as an outer protective layer) 12 disposed on one side of the polarizing member 11, and a protective layer disposed on the other side of the polarizing member 11 (hereinafter Sometimes also referred to as the inner protective layer) 13 and the adhesive layer 20. The adhesive layer 20 can be used to attach the polarizing plate 100 to the image display unit. It is also possible to omit one of the outer protective layer 12 or the inner protective layer 13 according to the purpose and desired configuration.

In the embodiment of the present invention, a through hole 30 is formed at or near the end of the polarizing plate 100. By forming the through hole, for example, the camera performance can be prevented from being adversely affected when the camera is embedded in the image display device. Moreover, by forming the through hole at or near the end of the polarizing plate, the influence of the polarizing plate on the image display can be minimized when the polarizing plate is applied to the image display device. The through hole can be formed by various methods such as laser processing, cutting with an end mill, and punching with a Thomson knife or a pointed knife. The polarizer representatively has a rectangular shape as shown in Figure 1. When referring to the "rectangular shape" in this specification, it also includes the shape of a special-shaped processed part such as an R shape obtained by chamfering each vertex as shown in FIG. 1. The through hole 30 may be provided at the substantially central part of the longitudinal end of the polarizing plate, may be provided at a predetermined position of the longitudinal end, or may be provided at the corner of the polarizing plate. When a through hole is provided at a predetermined position (including a substantially central portion) of an end in the longitudinal direction, the through hole is provided at a position such that the center of the hole is within 10 mm from the short side (end in the longitudinal direction), for example. In one embodiment, let the distance from the center of the polarizer in the longitudinal direction of FIG. 1 to the end in the longitudinal direction be L ₁ , and let the length from the center of the polarizer in the longitudinal direction to the center of the through hole be When the distance in the side direction is L ₂ , the through hole should be formed at a position satisfying 0.85≦L ₂ /L ₁ ≦0.99. L ₂ /L _{1 is} more preferably 0.90 to 0.97, and more preferably 0.92 to 0.96. When the through hole is provided in the corner, the through hole is provided, for example, such that the center of the hole is within 10 mm from the short side (end in the long side direction) and within 10 mm from the long side (end in the short side direction). In one embodiment, the through hole is preferably formed at a position satisfying 0.85≦L ₂ /L ₁ ≦0.99, and the distance from the center of the polarizer in the short-side direction to the end in the short-side direction is W ₁ , so When the short-side distance from the center of the short-side direction of the polarizer to the center of the through hole is W ₂ , it is formed at a position satisfying 0.50≦W ₂ /W ₁ ≦0.99. L ₂ /L _{1 is} more preferably 0.90 to 0.97, and more preferably 0.92 to 0.96. W ₂ /W _{1 is} more preferably 0.75 to 0.95. The example of the figure shows the case where the through hole is provided at the end in the long side direction, but the through hole can also be provided at the end in the short side direction. Although not shown, a plurality of through holes can be provided. In addition, the top view shape of the through hole can adopt any appropriate shape according to the purpose. Specific examples of the top-view shape include circles, ellipse circles, squares, rectangles, and combinations thereof (for example, the ends of the rectangles are arc-shaped). In addition, a special-shaped processing part (such as a U-shaped notch, a V-shaped notch) may be provided at the same time as the through hole is provided. The inventors of the present invention found that when a through hole is formed on a polarizing plate, a polarizing plate shift (essentially an adhesive layer shift) occurs in the through hole under a high temperature environment, and as a result, there is a risk of light leakage in the through hole. A new problem is solved by adopting the predetermined configuration of the embodiment of the present invention. That is, the present invention solves a new problem that has not yet been known, and the effect obtained by this is unpredictable and excellent.

In the embodiment of the present invention, as shown in FIG. 3, the polarizing plate 100 is supplied at 85°C in a state where the polarizing plate 100 is bonded to a glass plate (corresponding to the substrate of the image display unit) 120 through the adhesive layer 20 After the heating test for 120 hours, the offset D in the through hole 30 is 300 μm or less. The offset D is preferably 250 μm or less, preferably 200 μm or less, more preferably 150 μm or less, particularly preferably 120 μm or less, particularly preferably 100 μm or less, and most preferably 80 μm or less. The smaller the offset D, the better, and the lower the offset D is limited to 10 μm in one embodiment, and 20 μm in another embodiment. In addition, the offset D refers to the largest part of the polarizing plate away from the through hole when viewed in cross section. The reference representative of the through hole may be the lower end of the adhesive layer. That is, when the polarizing plate is deflected mainly due to the shrinkage of the polarizer 11 (to the right in the example of the drawing), it will stop at the glass plate 120 to which the adhesive layer 20 is adhered, and thus the deviation will be recognized in the through hole. . In addition, as shown in Fig. 3, the through-hole part of the polarizer representative is offset to the side away from the through-hole (the right side of Fig. 3), and the opposite part is shifted in the way that the through-hole protrudes in the past (Fig. 3 on the left). As mentioned above, according to the embodiment of the present invention, the newly discovered problem of the shift (essentially the shift of the adhesive layer) of the polarizing plate in the through hole part under high temperature environment can be solved, specifically, the predetermined heating The offset D after the test falls within the above-mentioned range.

In the embodiment of the present invention, the dimensional shrinkage rate of the polarizing plate after the above heating test is preferably 1.0% or less, preferably 0.6% or less, and more preferably 0.3% or less. The smaller the dimensional shrinkage, the better, and the lower limit of the dimensional shrinkage may be 0.01%, for example. In addition, the dimensional shrinkage rate can be obtained by the following formula. In addition, the size shrinkage rate is the size shrinkage rate of the entire polarizing plate attached to the glass plate, and when the polarizing plate further has an optical function layer (for example, a retardation layer, a reflective polarizer) as described later, it means that the optical function is included The overall size shrinkage of the polarizing plate of the layer. In addition, the "size" in the following formula refers to the size of the polarizing plate (substantially a polarizer) in the direction of the absorption axis. Dimensional shrinkage (%) = {(size before heating test-size after heating test)/size before heating test}×100

The diameter R of the 30 and a half through holes is preferably 10 mm or less, preferably 8 mm or less, and more preferably 5 mm or less. The lower limit of the diameter of the through hole may be 2 mm, for example, and may be 1.5 mm, for example. The ratio D/R of the offset D to the diameter R of the through hole is preferably 15% or less, preferably 10% or less, more preferably 6% or less, and particularly preferably 5% or less. On the other hand, the lower the D/R limit, the better. According to the embodiment of the present invention, the offset D is very small as described above, so even if the diameter of the through hole is reduced, D/R can be kept within the above range. Therefore, even if the diameter of the through hole is reduced, the adverse effect on the camera performance can be substantially prevented. As a result, the polarizing plate of the embodiment of the present invention can be applied to an image display device in which only the camera part is made into a non-display area and/or an image display device without a frame.

In the embodiment of the present invention, the polarizing plate representatively satisfies the following relationship: (A×T _pol )×(C _psa ×T _psa )/T _pro =K≦350×10 ² (μm ³ /hr) Here, A is The distance from the outermost part of the adhesive layer 20 in the thickness direction to the center of the polarizer 11 in the thickness direction (μm); T _pol is the thickness of the polarizer (μm); C _psa is the creep value of the adhesive layer (μm/ hr); T _psa is the thickness of the adhesive layer (μm); T _{pro is} the thickness _{of the} protective layer (μm). The "creep value" in this manual refers to the creep value at 85°C. The creep value can be measured, for example, according to the following procedure: stick the adhesive constituting the adhesive layer to the support plate. Fix the support plate to which the adhesive is attached, and apply a load of 500g under it in this state. Measure the offset of the adhesive from the support plate after applying the load for 1 hour, and use the offset as the creep value (μm/hr). Furthermore, the thickness T _pro of the protective layer in the above relational expression can be obtained from the formula: "total thickness of polarizing plate-thickness of adhesive layer-thickness of polarizer". That is, the total thickness of the protective layer 12 and the protective layer 13 of the T _pro system and the thickness of the adhesive layer used to attach the protective layer (including the thickness of the polarizer or protective film and the reflective polarizer when the polarizer is bonded through the adhesive layer) The total thickness of the adhesive layer) and the thickness of the surface treatment layer formed on the protective layer 12 as required. The K value is more preferably 250×10 ² (μm ³ /hr) or less, and preferably 200×10 ² (μm ³ /hr) or less, and particularly preferably 150×10 ² (μm ³ /hr) or less. The lower limit of the K value can be 15×10 ² (μm ³ /hr). As long as the K value is in the above range, the displacement of the through hole portion (essentially the displacement of the adhesive layer) can be significantly suppressed. The technical significance of setting the K value below the predetermined value is as follows: When the moment applied to the adhesive layer and the mobility of the adhesive layer itself are large, the offset of the adhesive layer will become larger, and when the pressure is applied to the adhesive layer The movement restraint force is large, the offset of the adhesive layer will be smaller. The moment applied to the adhesive layer is related to the distance from the image display unit to which the polarizing plate can be attached to the polarizing member and the thickness of the polarizing member; the mobility of the adhesive layer itself is related to the softness of the adhesive layer and The thickness is related; and the restraining force against the movement of the adhesive layer is related to the thickness of the protective layer. By reducing the distance from the image display unit to the polarizer and the thickness of the polarizer, the torque can be reduced; by setting the creep value of the adhesive layer below a predetermined value (make the adhesive layer harder) and make the adhesion The thickness of the agent layer is thin, so that the adhesive layer itself is not easy to move; by setting the thickness T _{pro of the} protective layer within a predetermined range, the restraining force against the movement of the adhesive layer can fall within an appropriate range. Therefore, by adjusting the above-mentioned requirements to control the K value below a predetermined value, the deviation of the adhesive layer can be significantly suppressed. Specifically, the aforementioned distance A is preferably 80 μm or less, and more preferably 50 μm or less. The lower limit of the distance A may be 10 μm, for example. The creep value C _{psa is} preferably 140 μm/hr or less, preferably 130 μm/hr or less, more preferably 120 μm/hr or less, and particularly preferably 100 μm/hr or less. The lower limit of the creep value may be 50 μm/hr, for example. The thickness T _{pro of the} protective layer is preferably 15 μm to 65 μm, more preferably 15 μm to 55 μm. The thickness T _{psa of the} adhesive layer is preferably 22 μm or less, more preferably 10 μm to 22 μm. If the creep value C _{psa is} too small and/or the thickness of the adhesive layer T _{psa is} too small, stress relaxation will become difficult, and the risk of cracking or peeling may increase. If the thickness T _{pro of the} protective layer is too small, it may be difficult to adjust the curl.

In the embodiment of the present invention, the thickness T _{pol of the} polarizing member 11 is preferably 20 μm or less, and preferably 15 μm or less, more preferably 12 μm or less, particularly preferably 10 μm or less, and particularly preferably 8 μm or less, particularly preferably 6 μm or less, most preferably It is preferably 5 μm or less. The lower limit of the thickness of the polarizer 11 is preferably 2 μm, more preferably 1 μm. By setting the thickness of the polarizer within the above range, the thermal shrinkage of the polarizer itself can be suppressed. As a result, the deformation of the adhesive layer that follows the thermal shrinkage of the polarizer can be suppressed (deflection in terms of the result).

For example, when the above-mentioned polarizing plate has a rectangular shape, the absorption axis direction of the polarizer is substantially parallel to the long side direction, and may also be substantially perpendicular to the long side direction. According to the embodiment of the present invention, even when the absorption axis direction of the polarizer is substantially parallel to the longitudinal direction, the offset of the polarizer can be reduced as described above. In other words, according to the embodiment of the present invention, even in the direction where the thermal shrinkage of the polarizing plate (substantially the polarizing member) is large, the amount of deviation can be reduced. And as mentioned above, the through hole can also be provided in the corner of the polarizing plate. The corner part is the part of the polarizing plate (essentially a polarizing member) that has a large thermal shrinkage, but according to the embodiment of the present invention, it can be the same as the above, and even in the part, the deviation of the polarizing plate can be reduced. In addition, in this specification, "substantially parallel" and "substantially parallel" mean that the angle formed by the two directions is 0°±7°, preferably 0°±5°, more preferably 0°±3°. The expressions of "substantially orthogonal" and "substantially orthogonal" include the case where the angle formed by the two directions is 90°±7°, preferably 90°±5°, and more preferably 90°±3°. In addition, when simply referring to "orthogonal" or "parallel" in this specification, it includes a state of being substantially orthogonal or substantially parallel. In addition, when referring to an angle in this specification, it includes both clockwise and counterclockwise with respect to the reference direction.

The polarizing plate of the embodiment of the present invention can be used as a viewing side polarizing plate, and can also be used as a back side polarizing plate. In addition, the polarizing plate of the embodiment of the present invention may have any appropriate optical function layer according to the purpose. Examples of the optical function layer include retardation layers, conductive layers for touch panels, and reflective polarizers.

In one embodiment, a retardation layer may be provided between the inner protective layer 13 and the adhesive layer 20. The retardation layer may be a single layer or a laminated structure. When the retardation layer is composed of a single layer, the retardation layer can function as a λ/4 plate. At this time, the in-plane retardation Re(550) of the retardation layer is preferably 100nm~200nm, more preferably 120nm~170nm, and more preferably 130nm~150nm. The angle formed by the absorption axis of the polarizer and the slow axis of the retardation layer is preferably 40°~50°, preferably 42°~48°, and more preferably 44°~46°. The retardation layer should exhibit reverse dispersion wavelength characteristics, that is, the retardation value will increase in accordance with the wavelength of the measured light. At this time, the Re(450)/Re(550) of the retardation layer is preferably 0.8 or more and less than 1, more preferably 0.8 or more and 0.95 or less. The retardation layer can be a stretched film of a resin film, or a directional curing layer of a liquid crystal compound. When the retardation layer is composed of a resin film, the retardation layer may also serve as an inner protective layer. Regarding the retardation layer composed of a stretched film of a resin film, it is described in, for example, Japanese Patent Application Publication No. 2017-54093 and Japanese Patent Application Publication No. 2018-60014. Specific examples of the liquid crystal compound and the details of the method for forming the oriented cured layer are described in, for example, Japanese Patent Application Laid-Open No. 2006-163343. This manual refers to the records in these bulletins as reference. In addition, "Re(λ)" in this specification refers to the in-plane phase difference measured with light of wavelength λnm at 23°C. For example, "Re(550)" is the in-plane phase difference measured with light with a wavelength of 550nm at 23°C. Re(λ) can be obtained by formula: Re(λ)=(nx-ny)×d when the thickness of the layer (film) is d(nm). nx is the refractive index in the direction in which the refractive index in the plane becomes the maximum (that is, the slow axis direction), and ny is the refractive index in the direction orthogonal to the slow axis in the plane (that is, the fast axis direction).

When the retardation layer has a laminated structure, the retardation layer representatively has an H layer and a Q layer in order from the polarizing plate side. The H layer represents the upper function as a λ/2 plate, and the Q layer represents the upper function as a λ/4 plate. The Re (550) of the H layer is preferably 200nm~300nm, preferably 230nm~290nm, more preferably 260nm~280nm. The angle formed by the absorption axis of the polarizer and the slow axis of the H layer is preferably 10°-20°, preferably 12°-18°, and more preferably 14°-16°. The Re(550) of the Q layer is preferably 100nm~200nm, preferably 120nm~170nm, more preferably 130nm~150nm. The angle formed by the absorption axis of the polarizer and the slow axis of the Q layer is preferably 70°~80°, preferably 72°~78°, and more preferably 74°~76°. The arrangement sequence of the H layer and the Q layer can be reversed, and the angle formed by the slow axis of the H layer and the absorption axis of the polarizer and the angle formed by the slow axis of the Q layer and the absorption axis of the polarizer can also be opposite. The H layer and the Q layer can be stretched films of resin films, or oriented solidified layers of liquid crystal compounds.

In one embodiment, a conductive layer for a touch panel may be provided on the side opposite to the polarizer of the inner protective layer 13 (or a retardation layer when present). As long as the structure is described above, the polarizing plate can be applied to a so-called internal touch panel type input display device in which a touch sensor is integrated between the image display unit and the polarizing plate. The polarizing plate of this embodiment is representative of the viewing side polarizing plate.

In one embodiment, a reflective polarizer may be provided on the side of the outer protective layer 12 opposite to the polarizer. The reflective polarizer can also serve as an outer protective layer. The polarizing plate of this embodiment is representatively a back-side polarizing plate. The details of the reflective polarizer are described in, for example, Japanese Patent Application Publication No. 9-507308 and Japanese Patent Application Publication No. 2013-235259. This manual refers to the records in these bulletins as reference.

The aspect ratio of the polarizing plate of the embodiment of the present invention is preferably 1.3~2.5. At this time, the size of the polarizing plate is, for example, 145 mm to 155 mm in length and 65 mm to 75 mm in width, or 230 mm to 240 mm in length and 140 mm to 150 mm in width. That is, the polarizing plate of the embodiment of the present invention can be suitably used for a smart phone or a tablet PC. The size of a smart phone, for example, can be 120mm~200mm in length and 30mm~120mm in width.

The above-mentioned embodiments can also be combined appropriately. For example, in the polarizing plate of the embodiment of the present invention, only the offset D may satisfy the expected value, only the K value may satisfy the expected value, or both the offset D and K may satisfy the above The expected value.

The polarizer, protective layer, and adhesive layer constituting the polarizing plate will be specifically described below.

B. Polarizing plate B-1. Polarizing parts The polarizer is typically composed of a resin film containing a dichroic substance. As for the resin film, any suitable resin film that can be used as a polarizer can be used. The resin film is typically a polyvinyl alcohol-based resin (hereinafter referred to as "PVA-based resin") film. The resin film may be a single-layer resin film or a laminate of two or more layers.

A specific example of a polarizing member composed of a single-layer resin film includes a PVA-based resin film that has been dyed and stretched with iodine (representatively, uniaxially stretched). The above-mentioned dyeing with iodine can be performed, for example, by immersing a PVA-based resin film in an iodine aqueous solution. The stretching ratio of the above uniaxial stretching is preferably 3~7 times. Stretching can be carried out after the dyeing treatment or while dyeing. Also, it can be dyed after stretching. The PVA resin film can be subjected to swelling treatment, cross-linking treatment, cleaning treatment, drying treatment, etc. according to demand. For example, immersing the PVA-based resin film in water for washing before dyeing can not only clean the dirt or anti-blocking agent on the surface of the PVA-based resin film, but also swell the PVA-based resin film to prevent uneven dyeing.

Specific examples of the polarizer obtained by using the laminate include a laminate using a resin substrate and a PVA resin layer (PVA resin film) laminated on the resin substrate, or a laminate using a resin substrate and coating A polarizer obtained by forming a laminate of PVA-based resin layers on the resin substrate. The polarizer obtained by using a laminate of a resin substrate and a PVA-based resin layer formed on the resin substrate can be produced, for example, by applying a PVA-based resin solution to the resin substrate and drying it, A PVA-based resin layer is formed on the resin substrate to obtain a laminate of the resin substrate and the PVA-based resin layer; and the laminate is extended and dyed to make the PVA-based resin layer into a polarizer. In this embodiment, stretching typically includes immersing the laminate in a boric acid aqueous solution and stretching. Furthermore, if necessary, stretching may further include stretching the laminate in the air at a high temperature (for example, 95° C. or higher) before stretching in an aqueous boric acid solution. The obtained resin substrate/polarizer laminate can be used directly (that is, the resin substrate can be used as the protective layer of the polarizer), or the resin substrate can be peeled from the resin substrate/polarizer laminate and placed on the release surface Lay any appropriate protective layer for later use depending on the purpose. The details of the manufacturing method of the polarizer are described in, for example, Japanese Patent Application Publication No. 2012-73580 and Japanese Patent No. 6470455. This specification uses the records of these patent documents as references.

The thickness of the polarizer is as described in item A above.

The polarizer should exhibit absorption dichroism at any wavelength from 380nm to 780nm. The single transmittance of the polarizer is, for example, 41.5%-46.0%, and preferably 43.0%-46.0%, more preferably 44.5%-46.0%. The degree of polarization of the polarizer is preferably 97.0% or more, preferably 99.0% or more, and more preferably 99.9% or more.

B-2. Protection layer The protective layer is formed of any suitable film that can be used as a protective layer of the polarizer. Specific examples of the material that becomes the main component of the film include cellulose resins such as cellulose triacetate (TAC), polyester, polyvinyl alcohol, polycarbonate, polyamide, and polyamide. Transparent resins such as imine-based, polyether-based, poly-based, polystyrene, polynorbornene, polyolefin, (meth)acrylic and acetate-based, etc. In addition, thermosetting resins such as (meth)acrylic type, urethane type, (meth)acrylate urethane type, epoxy type, and polysilicon type resin, or ultraviolet curing type resin, etc. may also be mentioned. Other examples include glassy polymers such as silicone polymers. In addition, the polymer film described in JP 2001-343529 A (WO01/37007) can also be used. As the material of the film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted amide group in the side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in the side chain can be used, for example, Examples include resin compositions having alternating copolymers composed of isobutylene and N-methylmaleimide and acrylonitrile-styrene copolymers. The polymer film may be, for example, an extruded product of the above-mentioned resin composition.

The outer protective layer 12 (especially when the polarizing plate is a viewing side polarizing plate) may also be subjected to surface treatments such as hard coating treatment, anti-reflection treatment, anti-adhesion treatment, and anti-glare treatment as needed. And/or, the outer protective layer 12 can also be processed as needed to improve the visibility through polarized sunglasses (representatively, imparting (elliptical) circular polarization function and ultra-high phase difference). By performing the above processing, even when viewing the display screen through a polarizing lens such as polarized sunglasses, excellent visibility can be achieved. Therefore, the polarizing plate can also be suitably used for image display devices that can be used outdoors.

The inner protective layer is preferably optically isotropic. In this specification, "optically isotropic" means that the in-plane retardation Re (550) is 0 nm to 10 nm, and the thickness direction retardation Rth (550) is -10 nm to +10 nm. Here, "Rth(λ)" is the thickness direction retardation measured with light of wavelength λnm at 23°C. For example, "Rth(550)" is the thickness direction retardation measured with light with a wavelength of 550nm at 23°C. Rth(λ) can be obtained by formula: Rth(λ)=(nx-nz)×d when the thickness of the layer (film) is d(nm). nz is the refractive index in the thickness direction.

The thickness of the protective layer can be any appropriate thickness. The thickness of the protective layer is, for example, 10 μm to 50 μm, and preferably 20 μm to 40 μm. In addition, when surface treatment is applied, the thickness of the protective layer includes the thickness of the surface treatment layer. In addition, the "thickness of the protective layer" mentioned here refers to the thickness of each of the outer protective layer and the inner protective layer, which is different from T _pro in the above formula.

C. Adhesive layer The adhesive layer 20, as described above, can be used to attach the polarizing plate to the image display unit. The adhesive layer can typically be composed of an acrylic adhesive (acrylic adhesive composition). The acrylic adhesive composition typically contains a (meth)acrylic polymer as a main component. The (meth)acrylic polymer may be contained in the adhesive composition at a ratio of, for example, 50% by weight or more, preferably 70% by weight or more, and more preferably 90% by weight or more in the solid content of the adhesive composition. The (meth)acrylic polymer contains an alkyl (meth)acrylate as a main component as a monomer unit. In addition, (meth)acrylate means acrylate and/or methacrylate. The alkyl (meth)acrylate is preferably contained in a ratio of 80% by weight or more in the monomer components forming the (meth)acrylic polymer, and more preferably in a ratio of 90% by weight or more. Examples of the alkyl group of the alkyl (meth)acrylate include a linear or branched alkyl group having 1 to 18 carbon atoms. The average carbon number of the alkyl group is preferably 3-9, more preferably 3-6. The preferred alkyl (meth)acrylate is butyl acrylate. The monomers (comonomers) constituting the (meth)acrylic polymer include carboxyl group-containing monomers, hydroxyl group-containing monomers, amine group-containing monomers, aromatic-containing monomers in addition to (meth)acrylic acid alkyl esters. Cyclo (meth)acrylates, heterocyclic ring-containing vinyl monomers, etc. Representative examples of comonomers include acrylic acid, 4-hydroxybutyl acrylate, phenoxyethyl acrylate, and N-vinyl-2-pyrrolidone. The acrylic adhesive composition preferably contains a silane coupling agent and/or a crosslinking agent. Examples of the silane coupling agent include epoxy-containing silane coupling agents. Examples of the crosslinking agent include isocyanate-based crosslinking agents and peroxide-based crosslinking agents. In addition, the acrylic adhesive composition may contain an antioxidant and/or a conductive agent. The thickness T _{psa of the} adhesive layer is, for example, 50 μm or less, and as described above, it is preferably 22 μm or less, and more preferably 10 μm to 22 μm. The details of the adhesive layer or the acrylic adhesive composition are described in, for example, Japanese Patent Application Publication No. 2006-183022, Japanese Patent Application Publication No. 2015-199942, Japanese Patent Application Publication No. 2018-053114, and Japanese Patent Application Publication No. 2016-190996 In the Bulletin No. and International Publication No. 2018/008712, the description of these bulletins is used for reference in this specification.

The storage elastic modulus G ₂ 'of the adhesive layer at -40°C should be 1.0×10 ⁵ (Pa) or more, and preferably 1.0×10 ⁶ (Pa) or more, more preferably 1.0×10 ⁷ (Pa) or more , Especially preferably 1.0×10 ⁸ (Pa) or more. The storage elastic modulus G ₂ ′ may be 1.0×10 ⁹ (Pa) or less, for example.

D. Image display device The polarizing plate of the embodiment of the present invention can be applied to an image display device. Therefore, the image display device is also included in the embodiment of the present invention. The image display device includes an image display unit and a polarizing plate. The polarizing plate is the polarizing plate of the embodiment of the present invention described in the above items A to C. The polarizing plate is attached to the image display unit through the adhesive layer. Examples of image display devices include liquid crystal display devices, organic electroluminescence (EL) display devices, and quantum dot display devices. Example

Hereinafter, the present invention will be specifically described with examples, but the present invention is not limited by these examples. The evaluation items of the embodiment are as follows. Moreover, as long as there is no special note, the "parts" and "%" in the examples are the basis of weight.

(1) Offset The polarizing plates obtained in the Examples and Comparative Examples were attached to a glass plate (manufactured by Matsunami Glass Ind., Ltd., length 350 mm × width 250 mm × thickness 1.1 mm) through an adhesive layer to prepare test samples. For this test sample, it is used for a heating test at 85°C and 120 hours. After the test, an optical microscope (MX61L) manufactured by OLYMPUS was used to measure the amount of deviation of the polarizing plate in the through-hole portion (substantially the adhesive layer). In addition, the measurement was performed on three test samples, and the maximum value of the three measurement values was used as the offset.

>Manufacturing Example 1> A monomer mixture containing 99 parts of butyl acrylate and 1 part of 4-hydroxybutyl acrylate was fed into a 4-necked flask equipped with a stirring blade, a thermometer, a nitrogen introduction tube, and a cooler. With respect to 100 parts of the monomer mixture (solid content), 0.1 part of 2,2'-azobisisobutyronitrile as a polymerization initiator and 100 parts by weight of ethyl acetate were fed together, and nitrogen was introduced while slowly stirring. After the nitrogen substitution, the liquid temperature in the flask was maintained at around 55°C, and the polymerization reaction was performed for 8 hours to prepare a solution (a) of an acrylic polymer with a weight average molecular weight (Mw) of 1.56 million. With respect to 100 parts of solid content of the obtained acrylic polymer (a) solution, 0.1 part of isocyanate crosslinking agent (trade name: TAKENATE D160N, trimethylolpropane hexamethylene diisocyanate, manufactured by Mitsui Chemicals Co., Ltd.) is blended , Benzyl peroxide (trade name: NYPER BMT 40SV, manufactured by Nippon Oil & Fat Co., Ltd.) 0.3 parts, thiol group-containing siloxane coupling agent (trade name: X-41-1810, manufactured by Shin-Etsu Chemical Co., Ltd., Amount of alkoxy group: 30%, thiol equivalent: 450 g/mol) 0.3 part and antioxidant (trade name: Irganox 1010, hindered phenol series, manufactured by BASF Japan) 0.2 part, and adhesive composition A was obtained.

>Manufacturing Example 2> Use a monomer mixture containing 81.8 parts of butyl acrylate, 16 parts of phenoxyethyl acrylate, 1.5 parts of N-vinyl-2-pyrrolidone, 0.3 parts of acrylic acid and 0.4 parts of 4-hydroxybutyl acrylate. In the same manner as in Production Example 1, a solution of acrylic polymer (b) with a weight average molecular weight (Mw) of 1.57 million was prepared. Acrylic polymer (b) is used. Silane coupling agent is a mercaptan-containing silane coupling agent (trade name: X-41-1056, manufactured by Shin-Etsu Chemical Co., Ltd.), alkoxy content: 30%, mercaptan equivalent : 450g/mol) 0.2 part, no antioxidant is used, and 0.5 part of lithium bis(trifluoromethanesulfonyl) imide (manufactured by Mitsubishi Materials Corporation) is further added, except for the above, in the same manner as in Production Example 1 The adhesive composition B was obtained.

>Manufacturing Example 3> Use a monomer mixture containing 80.3 parts of butyl acrylate, 16 parts of phenoxyethyl acrylate, 3 parts of N-vinyl-2-pyrrolidone, 0.3 parts of acrylic acid and 0.4 parts of 4-hydroxybutyl acrylate. In the same manner as in Production Example 1, a solution of acrylic polymer (c) having a weight average molecular weight (Mw) of 1.5 million was prepared. Use acrylic polymer (c), set the blending amount of silane coupling agent to 0.1 part, and add the conductive agent (1-ethyl-3-methylimidazole bis(trifluoromethanesulfonyl)imide), 5 parts of ionic liquid manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd., except for the above, the adhesive composition C was obtained in the same manner as in Production Example 1.

>Manufacturing Example 4> In the same manner as in Production Example 1, a solution of acrylic polymer (d) with a weight average molecular weight (Mw) of 1.65 million was prepared. With respect to 100 parts of the solid content of the obtained acrylic polymer (d) solution, 0.1 part of isocyanate crosslinking agent (trade name: TAKENATE D110N, trimethylolpropane hexamethylene diisocyanate, manufactured by Mitsui Chemicals Co., Ltd.) is blended , Benzyl peroxide (trade name: NYPER BMT 40SV, manufactured by Nippon Oil & Fats Co., Ltd.) 0.3 parts and silane coupling agent containing acetyl acetyl group (trade name: A-100, manufactured by Soken Chemical Co., Ltd.) 0.2 parts , And the adhesive composition D is obtained.

>Manufacturing Example 5> Silane coupling agent uses a mercaptan-containing silane coupling agent (trade name: X-41-1810, manufactured by Shin-Etsu Chemical Co., Ltd., alkoxy content: 30%, mercaptan equivalent: 450g/mol) 0.2 parts, except Otherwise, the adhesive composition E was obtained in the same manner as in Production Example 1.

>Example 1> The thermoplastic resin substrate is a long strip of amorphous isophthalic acid copolymer polyethylene terephthalate film (thickness: 100μm) with a Tg of about 75°C, and corona treatment is applied to one side of the resin substrate . PVA-based resin modified by 9:1 mixture of polyvinyl alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetyl acetyl group modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "GOHSEFIMER") 13 parts by weight of potassium iodide was added to 100 parts by weight, and the resultant was dissolved in water to prepare a PVA aqueous solution (coating liquid). The above-mentioned PVA aqueous solution was applied to the corona-treated surface of the resin substrate and dried at 60° C. to form a PVA-based resin layer with a thickness of 13 μm to produce a laminate. The obtained laminate was uniaxially stretched 2.4 times in the longitudinal direction (long side direction) in an oven at 130° C. (air-assisted stretching treatment). Next, the layered body was immersed in an insoluble bath (a boric acid aqueous solution obtained by blending 4 parts by weight of boric acid with respect to 100 parts by weight of water) at a liquid temperature of 40°C for 30 seconds (insoluble treatment). Next, adjust the concentration of the dyeing bath (with respect to 100 parts by weight of water, the iodine aqueous solution obtained by mixing iodine and potassium iodide at a weight ratio of 1:7) at a liquid temperature of 30°C so that the monomer transmittance of the polarizer obtained finally ( Ts) becomes the desired value and is immersed in it for 60 seconds at the same time (dyeing treatment). Next, it was immersed in a cross-linking bath (a boric acid aqueous solution obtained by mixing 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with respect to 100 parts by weight of water with a liquid temperature of 40°C) for 30 seconds (cross-linking treatment) . Then, while immersing the layered body in a boric acid aqueous solution (boric acid concentration of 4% by weight and potassium iodide concentration of 5% by weight) at a liquid temperature of 70°C, uniaxially stretched in the longitudinal direction (longitudinal direction) between rolls with different peripheral speeds In order to make the total extension ratio up to 5.5 times (in water extension treatment). After that, the layered body was immersed in a washing bath (an aqueous solution obtained by mixing 4 parts by weight of potassium iodide with respect to 100 parts by weight of water with a liquid temperature of 20°C) (washing treatment). After that, while drying in an oven maintained at about 90°C, the contact surface temperature was maintained at about 75°C with a heated roll made of SUS (drying shrinkage treatment). In the manner described above, a laminate having a resin substrate/polarizer configuration in which a polarizer with a thickness of about 5 μm is formed on a resin substrate is obtained. An HC-TAC film was attached as an outer protective layer to the surface of the polarizer (the surface on the opposite side to the resin substrate) of the obtained laminate. In addition, the HC-TAC film is a triacetyl cellulose (TAC) film (thickness 25 μm) with a hard coat (HC) layer (thickness 7 μm) formed on the film, and the TAC film is bonded to form the polarizer side. Next, the resin substrate was peeled, and the adhesive composition A was used on the peeled surface to form an adhesive layer (thickness 20 μm), and the polarizing plate 1 was obtained. The polarizing plate was punched to a size of 148mm in length and 70mm in width, and a through hole with a diameter of 3.9mm was formed in the corner. At this time, punching is performed with the absorption axis direction of the polarizer as the long side direction. The obtained polarizing plate was used for the evaluation in (1) above. The results are shown in Table 1 along with the detailed structure of the polarizing plate. In addition, in Table 1, "0°" refers to the long side direction, and "90°" refers to the short side direction.

>Example 2> In the same manner as in Example 1, a polarizing plate 1 was obtained. Except that the polarizer is set so that the absorption axis of the polarizer becomes the short-side direction, punching is performed in the same manner as in Example 1 to form through holes. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Table 1 together with the detailed structure of the polarizing plate.

>Example 3> The polarizing plate 2 was obtained in the same manner as in Example 1, except that the thickness of the adhesive layer was set to 15 μm. This polarizing plate was punched out in the same manner as in Example 1 to form through holes. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Table 1 together with the detailed structure of the polarizing plate.

>Example 4> The polarizing plate 2 was obtained in the same manner as in Example 3. The polarizing plate was punched in the same manner as in Example 2 to form through holes. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Table 1 together with the detailed structure of the polarizing plate.

>Example 5> In the same manner as in Example 1, a laminate having a resin substrate/polarizer configuration was obtained. An HC-cycloolefin resin film (HC thickness 2 μm, resin film thickness 25 μm) was bonded as an outer protective layer on the surface of the polarizer of the obtained laminate (the surface opposite to the resin substrate). Next, the resin base material was peeled, and a cycloolefin-based resin film (thickness 13 μm) was attached to the peeled surface as an inner protective layer. The adhesive composition A was used on the surface of the inner protective layer to form an adhesive layer (thickness 20 μm) to obtain a polarizing plate 3. This polarizing plate was punched out in the same manner as in Example 1 to form through holes. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Table 1 together with the detailed structure of the polarizing plate.

>Example 6> The polarizing plate 3 was obtained in the same manner as in Example 5. The polarizing plate was punched in the same manner as in Example 2 to form through holes. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Table 1 together with the detailed structure of the polarizing plate.

>Example 7> The polarizer used a film (thickness 12 μm) obtained by uniaxially extending a long polyvinyl alcohol (PVA)-based resin film containing iodine in the longitudinal direction (MD direction). On both sides of the polarizer, the long HC-TAC film to be the outer protective layer and the long acrylic resin film (thickness 20μm) to be the inner protective layer are attached so that the longitudinal directions of both sides are aligned. Together. The adhesive composition B was used on the surface of the inner protective layer to form an adhesive layer (thickness 20 μm) to obtain a polarizing plate 4. This polarizing plate was punched out in the same manner as in Example 1 to form through holes. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Table 1 together with the detailed structure of the polarizing plate.

>Example 8> The polarizing plate 4 was obtained in the same manner as in Example 7. The polarizing plate was punched in the same manner as in Example 2 to form through holes. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Table 1 together with the detailed structure of the polarizing plate.

>Example 9> Use cycloolefin resin film (thickness 13μm) instead of acrylic resin film as the inner protective layer, and use adhesive composition C instead of adhesive composition B to form the adhesive layer (thickness 20μm), other than that In the same manner as in Example 7, a polarizing plate 5 was obtained. This polarizing plate was punched out in the same manner as in Example 1 to form through holes. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Table 1 together with the detailed structure of the polarizing plate.

>Example 10> The polarizing plate 5 was obtained in the same manner as in Example 9. The polarizing plate was punched in the same manner as in Example 2 to form through holes. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Table 1 together with the detailed structure of the polarizing plate.

>Example 11> A polarizing plate was obtained in the same manner as in Example 7, except that a TAC film (thickness 25 μm) was used instead of the acrylic resin film as the inner protective layer. The liquid crystal orientation curing layer H and the liquid crystal orientation curing layer Q are sequentially transferred to the inner protective layer side of the polarizing plate. In addition, the liquid crystal orientation curing layer H and the liquid crystal orientation curing layer Q are produced in the following manner. The adhesive composition D is used on the surface of the liquid crystal oriented curing layer Q to form an adhesive layer (thickness 20 μm) to obtain a polarizing plate (polarizing plate with retardation layer) 6. The polarizing plate was punched in the same manner as in Example 2 to form through holes. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Table 1 together with the detailed structure of the polarizing plate.

使用擦拭布擦拭聚對苯二甲酸乙二酯(PET)薄膜(厚度38μm)表面，施行定向處理。定向處理之方向係設為貼合至偏光板時由視辨側觀看時相對於偏光件之吸收軸方向呈15°方向。利用棒塗機將上述液晶塗敷液塗敷至該定向處理表面，並於90℃下進行2分鐘加熱乾燥，藉此使液晶化合物定向。使用金屬鹵素燈以1mJ/cm² 的光照射依上述方式形成的液晶層，使該液晶層硬化，藉此於PET薄膜上形成液晶定向固化層H。液晶定向固化層H的厚度為2.5μm，面內相位差Re(550)為270nm。並且，液晶定向固化層H具有nx＞ny＝nz之折射率分布。 變更塗敷厚度，並將定向處理方向設為由視辨側觀看時相對於偏光件之吸收軸方向呈75°方向，除此之外依與上述相同方式於PET薄膜上形成液晶定向固化層Q。液晶定向固化層Q的厚度為1.5μm，面內相位差Re(550)為140nm。並且，液晶定向固化層Q具有nx＞ny＝nz之折射率分布。10g of polymerizable liquid crystal (manufactured by BASF Corporation: trade name "Paliocolor LC242", represented by the following formula) showing a nematic liquid crystal phase and a photopolymerization initiator (manufactured by BASF Corporation: trade name "IRGACURE") of the polymerizable liquid crystal compound 907") 3 g was dissolved in 40 g of toluene to prepare a liquid crystal composition (coating liquid). [Chemical formula 1]

Wipe the surface of a polyethylene terephthalate (PET) film (thickness 38 μm) with a wiping cloth, and perform orientation treatment. The direction of the orientation treatment is set to be 15° with respect to the absorption axis direction of the polarizer when viewed from the viewing side when attached to the polarizer. The above-mentioned liquid crystal coating liquid was applied to the alignment-treated surface using a bar coater, and heated and dried at 90°C for 2 minutes, thereby aligning the liquid crystal compound. A metal halide lamp was used to irradiate the liquid crystal layer formed in the above manner with light of 1 mJ/cm ² to harden the liquid crystal layer, thereby forming a liquid crystal orientation cured layer H on the PET film. The thickness of the liquid crystal orientation cured layer H was 2.5 μm, and the in-plane phase difference Re (550) was 270 nm. In addition, the liquid crystal orientation curing layer H has a refractive index distribution of nx>ny=nz. Change the coating thickness and set the orientation treatment direction to be 75° with respect to the absorption axis direction of the polarizer when viewed from the viewing side, except that the liquid crystal orientation cured layer Q is formed on the PET film in the same manner as above . The thickness of the liquid crystal orientation cured layer Q was 1.5 μm, and the in-plane phase difference Re (550) was 140 nm. In addition, the liquid crystal orientation curing layer Q has a refractive index distribution of nx>ny=nz.

>Example 12> A polarizing plate was obtained in the same manner as in Example 7 except that a TAC film (thickness 25 μm) was used instead of the HC-TAC film as the outer protective layer. After bonding a reflective polarizer (thickness 26 μm) on the surface of the outer protective layer through a general adhesive layer, the adhesive composition E is used to form an adhesive layer (thickness 20 μm) on the surface of the reflective polarizer to obtain a polarizing plate 7. This polarizing plate was punched out in the same manner as in Example 1 to form through holes. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Table 1 together with the detailed structure of the polarizing plate.

>Example 13> The polarizing plate 7 was obtained in the same manner as in Example 12. The polarizing plate was punched in the same manner as in Example 2 to form through holes. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Table 1 together with the detailed structure of the polarizing plate.

>Example 14> In the same manner as in Example 1, a laminate having a resin substrate/polarizer configuration was obtained. A TAC film (thickness 20 μm) was attached to the surface of the polarizer of the obtained laminate (the surface on the opposite side to the resin substrate) as an inner protective layer. Next, the resin base material was peeled, and a reflective polarizer (thickness 26 μm) was bonded to the peeled surface. The adhesive composition D was used on the surface of the inner protective layer to form an adhesive layer (thickness 20 μm) to obtain a polarizing plate 8. This polarizing plate was punched out in the same manner as in Example 1 to form through holes. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Table 1 together with the detailed structure of the polarizing plate.

>Example 15> The polarizing plate 8 was obtained in the same manner as in Example 14. The polarizing plate was punched in the same manner as in Example 2 to form through holes. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Table 1 together with the detailed structure of the polarizing plate.

>Comparative Example 1> The polarizer used a film (thickness 22 μm) obtained by uniaxially extending a long polyvinyl alcohol (PVA)-based resin film containing iodine in the longitudinal direction (MD direction). On both sides of the polarizer, the long TAC film (thickness 40μm) to be the outer protective layer and the long acrylic resin film (thickness 30μm) to be the inner protective layer are respectively aligned so that the longitudinal directions of both sides are aligned. The way fits. The adhesive composition D was used on the surface of the inner protective layer to form an adhesive layer (thickness 20 μm) to obtain a polarizing plate 9. This polarizing plate was punched out in the same manner as in Example 1 to form through holes. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Table 1 together with the detailed structure of the polarizing plate.

>Comparative Example 2> The polarizing plate 9 was obtained in the same manner as in Comparative Example 1. The polarizing plate was punched in the same manner as in Example 2 to form through holes. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Table 1 together with the detailed structure of the polarizing plate.

>Example 16> In the same manner as in Example 1, a polarizing plate 1 was obtained. The polarizing plate was punched out to a size of 152 mm in length and 73 mm in width, and a through hole with a diameter of 4.7 mm was formed at the center of the end in the longitudinal direction. At this time, punching is performed with the absorption axis direction of the polarizer as the long side direction. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Table 1 together with the detailed structure of the polarizing plate.

>Example 17> The polarizing plate 3 was obtained in the same manner as in Example 5. The polarizing plate was punched in the same manner as in Example 16 to form through holes. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Table 1 together with the detailed structure of the polarizing plate.

>Example 18> The polarizing plate 3 was obtained in the same manner as in Example 5. Except that the polarizing plate was set so that the absorption axis of the polarizer became the short-side direction, punching was performed in the same manner as in Example 16 to form through holes. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Table 1 together with the detailed structure of the polarizing plate.

>Example 19> The polarizing plate 4 was obtained in the same manner as in Example 7. The polarizing plate was punched in the same manner as in Example 16 to form through holes. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Table 1 together with the detailed structure of the polarizing plate.

>Example 20> The polarizing plate 10 was obtained in the same manner as in Example 9, except that the adhesive composition B was used instead of the adhesive composition C to form an adhesive layer (thickness 20 μm). This polarizing plate was punched in the same manner as in Example 18 to form through holes. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Table 1 together with the detailed structure of the polarizing plate.

>Comparative Example 3> The polarizing plate 9 was obtained in the same manner as in Comparative Example 1. The polarizing plate was punched in the same manner as in Example 16 to form through holes. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Table 1 together with the detailed structure of the polarizing plate.

>Examples 21~28> With the configuration shown in Table 1, a polarizing plate having through holes was produced. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are listed in Table 1.

[Table 1]

It can be seen from Table 1 that the offset of the through hole portion of the polarizing plate of the embodiment of the present invention after the heating test is significantly smaller than that of the comparative example. In addition, graphs showing the relationship between the K value and the offset of the polarizing plate with the absorption axis in the 0° direction (for example, Example 1) and the polarizing plate with the absorption axis in the 90° direction (for example, Example 2) are listed in the figure. 4 and Figure 5. It can be seen from FIGS. 4 and 5 that by reducing the K value, the offset will become smaller, and the relationship is highly correlated.

Industrial availability The polarizing plate of the present invention can be suitably used for image display devices, especially suitable for image display devices with cameras represented by smart phones, tablet PCs or smart watches.

11: Polarizing member 12: Outer protective layer 13: Inner protective layer 20: Adhesive layer 30: Through hole 100: Polarizing plate 120: Glass plate A: From the outermost part of the thickness direction of the adhesive layer to the center of the thickness direction of the polarizing member Distance to the end D: Offset L ₁ : Distance from the center of the polarizer in the longitudinal direction to the end in the longitudinal direction L ₂ : Distance in the longitudinal direction from the center of the polarizer in the longitudinal direction to the center of the through hole R : The diameter of the through hole W ₁ : The distance from the center of the short side of the polarizer to the end in the short side direction W ₂ : The distance from the center of the short side of the polarizer to the center of the through hole in the short side direction II-II: line

Fig. 1 is a schematic plan view illustrating the formation position of a through hole in a polarizing plate according to an embodiment of the present invention. Fig. 2 is a schematic cross-sectional view taken along the line II-II of the polarizing plate shown on the left side of Fig. 1. Fig. 3 is an enlarged cross-sectional view of an important part illustrating the shift of the through hole portion in the polarizing plate of the embodiment of the present invention. FIG. 4 is a graph showing the relationship between the K value and the offset of the polarizing plate with the absorption axis in the 0° direction obtained in the examples and comparative examples. FIG. 5 is a graph showing the relationship between the K value and the offset of the polarizing plate with the absorption axis in the 90° direction obtained in the Examples and Comparative Examples.

11: Polarizing parts

12: Outer protective layer

13: Inside protective layer

20: Adhesive layer

30: Through hole

100: Polarizing plate

Claims (15)

A polarizing plate having a polarizing element, a protective layer and an adhesive layer arranged on at least one side of the polarizing element; and The polarizing plate has a through hole formed at or near the end; After the polarizing plate was attached to the glass plate through the adhesive layer and subjected to a heating test at 85° C. and 120 hours, the amount of deviation of the polarizing plate at the through hole portion was 300 μm or less. A polarizing plate having a polarizing member, a protective layer and an adhesive layer arranged on at least one side of the polarizing member; and the polarizing plate is formed with a through hole at or near the end portion; from the outermost part of the adhesive layer in the thickness direction The distance A (μm) to the center of the thickness direction of the polarizer, the thickness T _pol (μm) of the polarizer, the creep value C _psa (μm/hr) of the adhesive layer, the thickness of the adhesive layer T _psa (μm) and the thickness of the protective layer T _pro (μm) satisfy the following relationship: (A×T _pol )×(C _psa ×T _psa )/T _pro =K≦350×10 ² (μm ³ /hr ). The polarizing plate of claim 1 or 2, wherein the thickness T _pol of the aforementioned polarizing member is 20 μm or less. The polarizing plate of claim 3, wherein the thickness T _pol of the aforementioned polarizing member is 10 μm or less. The polarizing plate according to any one of claims 1 to 4, wherein the offset of the polarizing plate at the through hole portion is 120 μm or less. The polarizing plate according to any one of claims 1 to 5, wherein the thickness T _psa of the aforementioned adhesive layer is 10 μm to 22 μm. The polarizing plate according to any one of claims 1 to 6, wherein the offset of the polarizing plate is substantially the offset of the adhesive layer. The polarizing plate according to any one of claims 1 to 7, wherein the aforementioned through hole is formed in the corner. Such as the polarizing plate of claim 8, wherein the distance from the center in the longitudinal direction to the end in the longitudinal direction is L ₁ when the polarizer is viewed from above, and the distance from the center in the longitudinal direction of the polarizer to the center of the through hole is The long-side distance of the polarizer is L ₂ , the distance from the center of the short-side direction of the polarizer to the end of the short-side direction is W ₁ , and the distance from the center of the short-side direction of the polarizer to the center of the through hole is When the distance in the short-side direction is W ₂ , the through hole is formed at a position satisfying 0.85≦L ₂ /L ₁ ≦0.99 and 0.50≦W ₂ /W ₁ ≦0.99. The polarizing plate according to any one of claims 1 to 9, which has a rectangular shape, and the absorption axis direction of the aforementioned polarizer is substantially parallel to the longitudinal direction. The polarizing plate according to any one of claims 1 to 10, wherein the protective layer is only disposed on one side of the polarizing member. The polarizing plate of any one of claims 1 to 11, wherein the diameter of the through hole is 10 mm or less. For example, the polarizing plate of any one of claims 1 to 12 has an aspect ratio of 1.3 to 2.5. The polarizing plate of claim 1, wherein the distance A (μm) from the outermost part in the thickness direction of the adhesive layer to the center in the thickness direction of the polarizing member, the thickness T _pol (μm) of the polarizing member, and the adhesive The creep value of the layer C _psa (μm/hr), the thickness T _psa (μm) of the adhesive layer and the thickness T _pro (μm) of the aforementioned protective layer satisfy the following relationship: (A×T _pol )×(C _psa ×T _psa )/T _pro =K≦350×10 ² (μm ³ /hr). An image display device comprising an image display unit and a polarizing plate as claimed in any one of claims 1 to 14, and The polarizing plate is attached to the image display unit through the adhesive layer.

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