JP6664866B2 - Set of polarizing plate and front panel integrated liquid crystal display panel - Google Patents

Description

  A set of polarizing plates consisting of a rear polarizing plate and a front polarizing plate in which the front plate is integrated with different dimensional shrinkage ratios in a high temperature environment, and a front plate integrated liquid crystal display panel in which these are bonded to a liquid crystal cell It is about.

  Liquid crystal display devices have been used in desktop calculators, electronic watches, personal computers, etc., but their demand has been increasing rapidly in recent years, and recently they are also used in mobile phones and tablet terminals. Its uses are expanding. In these liquid crystal display devices, a pair of polarizing plates are usually arranged on the front and back of a liquid crystal cell to form a liquid crystal display panel.

  In the recent market, with the spread of mobile devices such as mobile phones and tablet-type terminals with larger screens, the weight and thickness of the liquid crystal display panels that are the components of the devices have been required to be reduced. The front plate tends to be thin. In addition, in order to improve visibility by eliminating reflection and scattering of light at the interface, the front plate tends to be integrated with the liquid crystal display panel with an adhesive or an ultraviolet curable resin.

  In the conventional liquid crystal display panel, since the front plate and the liquid crystal cell are thick, the warpage due to the shrinkage of the polarizing plate was suppressed even in a high temperature environment, but it has been used for the recent front plate thickness and the liquid crystal cell as described above. With the tendency to make the glass thinner, there is a problem that the liquid crystal display panel warps due to the shrinkage of the polarizing plate in a high-temperature environment and cannot be accommodated in the housing of the final product.

  In order to suppress such warpage of the liquid crystal display panel, the thickness of the polarizing plate disposed on the side opposite to the viewing side of the liquid crystal cell and the side opposite to the viewing side of the liquid crystal cell (back side) has been changed. Techniques for suppressing panel warpage have been developed. For example, in Japanese Unexamined Patent Application Publication No. 2012-58429 (Patent Document 1), the thickness of a polarizing film (a polarizer in the present invention) of a polarizing plate arranged on the viewing side of a liquid crystal cell is arranged on the back side of the liquid crystal cell. A method of suppressing warpage of a liquid crystal display panel by making it thinner than a polarizing film is described.

  However, the warpage of the liquid crystal display panel under a high temperature environment is caused by the shrinkage of the polarizer due to the thickness of the polarizer as described above. When thinner, especially in the case of a liquid crystal display panel in which the front panel is integrated with an adhesive or an ultraviolet curable resin to improve visibility, warpage may occur, and suppression of warpage is not necessarily Not satisfactory.

  Japanese Patent No. 4666430 (Patent Document 2) discloses a liquid crystal display element using a plastic substrate liquid crystal cell (a liquid crystal display panel according to the present invention). It describes a liquid crystal display device in which the amount of warpage of a plastic substrate liquid crystal cell is suppressed by changing the thickness of the film. According to this method, although the object of suppressing the warpage of the liquid crystal cell has been achieved, if the front plate is integrated with the polarizing plate in a high temperature environment in order to improve the visibility, Patent Document 2 In the method of changing the thickness of the protective film as described above, the liquid crystal cell may be warped due to the heat shrinkage of the protective film, which may cause a problem that the liquid crystal cell cannot be accommodated in the casing of the final product.

JP 2012-58429 A Japanese Patent No. 4666430 (Japanese Patent Application Laid-Open No. 2002-221715)

The present invention has been made in order to solve the above conventional problems, and its main purpose is to
It is an object of the present invention to provide a set of polarizing plates that suppresses the amount of warpage in a high-temperature environment when used as a liquid crystal display panel, and a front panel integrated liquid crystal display panel obtained by bonding the set of polarizing plates to a liquid crystal cell. is there.

  That is, in the present invention, the front plate disposed on the viewing side of the liquid crystal cell and having a Young's modulus of 2 GPa or more and being far from the liquid crystal cell is bonded to the front polarizing plate via an ultraviolet curable resin or an adhesive. A front plate-integrated polarizing plate and a rear polarizing plate disposed on the back side of the liquid crystal cell, wherein the front polarizing plate is not bonded to the front plate and is heated at 85 ° C. to 100 ° C. A set of polarizing plates, wherein the dimensional change in the absorption axis direction when heated for a period of time is greater than the dimensional change in the absorption axis direction when heated at 85 ° C. for 100 hours. It is.

In the above set of polarizing plates, the front-side polarizing plate has a dimensional change in the absorption axis direction of 1.2% or more when heated at 85 ° C. for 100 hours without being bonded to the front plate, and is preferably 1% or more. Preferably, the polarizing plate has a dimensional change rate of 1.1% or less in the direction of the absorption axis when heated at 85 ° C. for 100 hours.

  In the set of polarizing plates, both the front-side polarizing plate and the back-side polarizing plate have a structure in which a transparent protective film is laminated on at least one surface of a polarizer made of a polyvinyl alcohol-based resin film, and May be a set of polarizing plates in which the transparent protective film on the liquid crystal cell side has an in-plane retardation.

  In the set of polarizing plates, the front-side polarizing plate and the rear-side polarizing plate both have a structure in which a transparent protective film is laminated on both surfaces of a polarizer made of a polyvinyl alcohol-based resin film, and the front-side polarizing plate The set of polarizers may be a set of polarizers thicker than the polarizers of the rear-side polarizer.

  It is preferable that another optical film is laminated on the back side polarizing plate on a side far from the liquid crystal cell.

  It is preferable that the absorption axis of the front side polarizing plate is in the short side direction of the liquid crystal cell, and the absorption axis of the back side polarizing plate is in the long side direction of the liquid crystal cell.

  The present invention also includes any one of the above-described sets of polarizing plates and a liquid crystal cell, and a front plate integrated polarizing plate constituting the set of polarizing plates is adhered on the polarizing plate side to the viewing side of the liquid crystal cell. The back side polarizing plate constituting the set of polarizing plates is adhered to the back side of the liquid crystal cell, and the amount of warpage when heated at 85 ° C. for 240 hours is 0.5 mm or less in absolute value, preferably , 0.3 mm or less.

  ADVANTAGE OF THE INVENTION According to this invention, the curvature in a high temperature environment in the liquid crystal display panel which integrated the front panel can be eliminated, and the front panel integrated liquid crystal display panel which fits in the housing | casing of the final product in a high temperature environment is obtained. be able to.

FIG. 3 is a schematic cross-sectional view illustrating an example of a preferred layer configuration in a set of polarizing plates according to the present invention. FIG. 2 is a schematic sectional view showing an example of a preferred layer configuration in the front panel integrated liquid crystal display panel according to the present invention.

  Hereinafter, a set of polarizing plates according to the present invention and a front panel integrated liquid crystal display panel using the same will be described with reference to the drawings as appropriate, but the present invention is not limited to these embodiments.

  First, the set of polarizing plates of the present invention includes a front plate integrated polarizing plate 40 and a rear polarizing plate 50. FIG. 1 is a schematic sectional view showing an example of a preferred layer configuration in the set of polarizing plates according to the present invention. Referring to FIG. 1, a front plate integrated polarizing plate 40 constituting a set of polarizing plates of the present invention is arranged on a viewing side of a liquid crystal cell, and a front plate 10 arranged on a side far from the liquid crystal cell has a front surface. It is bonded to the side polarizing plate 30 via an ultraviolet curable resin or an adhesive 20. In addition, the front-side polarizing plate 30 is obtained by bonding transparent protective films 35a and 35b of the front-side polarizing plate to both surfaces of the polarizer 37 of the front-side polarizing plate. Further, the rear-side polarizing plate 50 is formed by bonding transparent protective films 55a and 55b of the rear-side polarizing plate to both surfaces of the polarizer 57 of the rear-side polarizing plate.

  The front plate 10 in the present invention has a Young's modulus of 2 GPa or more from the role of suppressing and protecting the liquid crystal cell from warping. The front plate 10 may be a single layer or a laminated one as long as it satisfies the above Young's modulus. As described above, since it is arranged on the viewing side of the liquid crystal cell, specifically, the outermost surface of the final product, it is expected to be used outdoors or semi-outdoors. Therefore, from the viewpoint of durability, it is preferable to be composed of inorganic materials such as glass and tempered glass, and organic materials such as polycarbonate resin and acrylic resin. The front plate may be, for example, tempered glass or a film constituting a touch panel as long as the Young's modulus is 2 GPa or more. The type of the touch panel is not particularly limited, and examples thereof include a capacitance type, a surface acoustic wave type, a resistive film type, an electromagnetic induction type, an optical sensor type, and an infrared type. The front plate 10 may have functions such as antireflection, antifouling, electromagnetic wave shielding, near-infrared shielding, color adjustment, and glass scattering prevention. The front plate having such a function may be, for example, one in which at least one or more film layers having these functions are laminated on at least one surface of the front plate. Such a multi-layer front plate is, for example, a method of directly applying an effective agent to impart the above function to the substrate of the organic material or the inorganic material as described above, or a function having the above-described function separately created. It may be made by laminating the film.

  It is preferable that the ultraviolet curable resin or the adhesive 20 for bonding the front plate 10 and the front-side polarizing plate 30 is transparent whose refractive index is close to that of the front plate 10. By employing such an ultraviolet-curable resin or pressure-sensitive adhesive, reflection and light scattering at the interface between the front plate and the polarizing plate can be eliminated, and visibility can be improved.

  As the UV-curable resin, a general UV-curable liquid such as (meth) acrylate or epoxy resin can be used. In addition, as the pressure-sensitive adhesive, those having a base polymer of an acrylic polymer, a silicone-based polymer, polyester, polyurethane, polyether, or the like can be used. Among them, it is preferable to use an acrylic adhesive having excellent optical transparency and high transparency, such as an acrylic adhesive. Here, “(meth) acrylate” means that either acrylate or methacrylate may be used, and “(meth)” when referring to (meth) acrylate and the like has the same meaning. is there.

  In the present invention, the front-side polarizing plate 30 composed of the polarizer 37 preferably has a dimensional change rate of 1 in the stretching direction (hereinafter also referred to as absorption axis direction) of the film when heated at 85 ° C. for 100 hours. 0.2% or more and 3.0% or less, more preferably 1.3% or more and 2.0% or less. If the upper limit of the dimensional change rate of the front side polarizing plate greatly exceeds 3.0%, there is a possibility that the polarizing plate shrinks in a high temperature environment and peels off from the liquid crystal cell.

The rear-side polarizing plate 50 to which the polarizer 57 is applied preferably has a dimensional change in the absorption axis direction of 0.1% or more and 1.1% or less when heated at 85 ° C. for 100 hours. More preferably, it is not less than 0.5% nor more than 1.1%. If the lower limit value of the dimensional change rate of the rear-side polarizing plate is lower than 0.1%, the optical characteristics are hindered, and a problem of low contrast during liquid crystal display may occur.

In the polarizer set of the present invention, the polarizer 37 constituting the front polarizer is a rear polarizer 57 (hereinafter referred to as a polarizer) constituting the rear polarizer 50 disposed on the rear side of the liquid crystal cell. A thicker form is preferred. The thickness of the polarizer 37 constituting the front-side polarizing plate is preferably 20 μm or more. The thickness of the polarizer 57 of the rear polarizing plate 50 of the liquid crystal cell is preferably 15 μm or less. Arranging a set of polarizing plates satisfying these conditions on both sides of the liquid crystal cell 60 is effective for suppressing the amount of warpage of the liquid crystal display panel (FIG. 2) having the front panel integrated.

  As the polarizer used for the front and rear polarizers, any appropriate polarizer can be used as long as the above-mentioned conditions regarding the dimensional change and / or the thickness of the polarizer are satisfied. As the polarizer, a polarizer in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film is used. The polyvinyl alcohol resin constituting the polarizer can be obtained by saponifying a polyvinyl acetate resin. Examples of the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and a copolymer of vinyl acetate and another monomer copolymerizable therewith. Examples of other monomers copolymerized with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group. The saponification degree of the polyvinyl alcohol-based resin is usually about 85 to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol-based resin may be further modified. For example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The polymerization degree of the polyvinyl alcohol-based resin is generally about 1,000 to 10,000, preferably about 1,500 to 5,000. Specific examples of the polyvinyl alcohol-based resin and the dichroic dye include a polyvinyl alcohol-based resin and a dichroic dye exemplified in JP-A-2012-159778.

  A film formed of such a polyvinyl alcohol-based resin is used as a raw film of a polarizer. The method of forming the polyvinyl alcohol-based resin is not particularly limited, and the film can be formed by a known method such as the method described in JP-A-2012-159778. The thickness of the raw film made of a polyvinyl alcohol-based resin is not particularly limited, but is, for example, about 1 to 150 μm. In consideration of the ease of stretching, the film thickness is preferably 10 μm or more.

  Further, the polarizer is, for example, a step of uniaxially stretching the polyvinyl alcohol-based resin film as described above, a step of adsorbing the dichroic dye by dyeing the polyvinyl alcohol-based resin film with a dichroic dye, The polyvinyl alcohol-based resin film to which the dichroic dye is adsorbed is subjected to a process of treating with a boric acid aqueous solution and a process of washing with water after the treatment with the boric acid aqueous solution. Stretching, dyeing, boric acid treatment, washing with water, and drying of the polyvinyl alcohol-based resin film in the production process of the polarizer may be performed, for example, according to the method described in JP-A-2012-159778.

  Both the front polarizing plate 30 and the rear polarizing plate 50 defined in the present invention have a structure in which a transparent protective film is laminated on at least one surface of the polarizer manufactured as described above. As the transparent protective film, a film formed of an appropriate transparent resin can be used. Specifically, it is preferable to use a polymer that is excellent in transparency, uniform optical characteristics, mechanical strength, thermal stability, and the like. Examples of such a transparent protective film include cellulose films such as triacetyl cellulose and diacetyl cellulose, polyester films such as polyethylene terephthalate, polyethylene isophthalate and polybutylene terephthalate, polymethyl (meth) acrylate and polyethyl (meth) acrylate. Acrylic resin-based films, polycarbonate-based films, polyethersulfone-based films, polysulfone-based films, polyimide-based films, polyolefin-based films, polynorbornene-based films, and the like can be used, but are not limited thereto.

  The transparent protective films 35a and 35b applied to the front polarizer 30 and the transparent protective films 55a and 55b applied to the rear polarizer 50 may be the same, or may be independent and different. You may. Further, a form in which neither or one of the transparent protective films 35b and 55a closer to the liquid crystal cell is provided may be used. In the invention, it is preferable that the transparent protective film provided on the liquid crystal cell side of at least one of the polarizing plates has an in-plane retardation.

  The in-plane retardation of the transparent protective film can be provided by uniaxial stretching or biaxial stretching. The in-plane retardation value may be appropriately set according to the type of liquid crystal cell to be applied, but is generally preferably 30 nm or more. Although the upper limit of the in-plane retardation value is not particularly limited, for example, up to about 300 nm is sufficient.

Prior to lamination to the polarizer, the transparent protective film may be subjected to an easy adhesion treatment such as a saponification treatment, a corona treatment, a primer treatment, and an anchor coating treatment.
The thickness of the transparent protective film is usually in the range of about 5 to 200 μm, preferably 10 μm or more, more preferably 80 μm or less, and further preferably 40 μm or less.

  On the surface of the transparent protective film, a surface treatment layer such as a hard coat layer, an antireflection layer or an antiglare layer may be provided as necessary. The hard coat layer is a surface treatment layer formed to prevent the polarizing plate surface from being damaged, and is mainly composed of an ultraviolet-curable resin, for example, an acrylic or silicone resin, from which the adhesiveness and hardness of the transparent protective film are increased. Is selected as appropriate and can be formed on the surface of the transparent protective film.

  The antireflection layer is a surface treatment layer formed on the surface of the polarizing plate for the purpose of preventing reflection of external light, and can be formed by a known method. The anti-glare layer is a surface treatment layer formed to prevent visibility from being impaired when external light is reflected on the surface of the polarizing plate, and is, for example, a surface roughening method such as a sand blast method or an embossing method. In general, the transparent protective film is formed so as to have an uneven surface by a method of mixing transparent fine particles with an ultraviolet curable resin.

  A polarizing plate is obtained by laminating the transparent protective film on at least one surface of a polarizer. The polarizing plate may be one obtained by laminating the above-mentioned transparent protective film on both surfaces of a polarizer. The bonding of the polarizer and the transparent protective film is not particularly limited, but can be performed using an adhesive or an adhesive made of an epoxy polymer. Such an adhesive layer or a pressure-sensitive adhesive layer is formed as a coating and drying layer of an aqueous solution, but when adjusting the aqueous solution, other additives or a catalyst such as an acid can be blended as necessary. .

  In the present invention, the polarizing plate can be used by laminating one or two or more optical layers exhibiting other optical functions when used. The optical layer is not particularly limited, and examples thereof include a reflective layer, a semi-transmissive reflective layer, a retardation plate, and a brightness enhancement film. On the polarizing plate comprising the polarizer and the transparent protective film, an elliptically polarizing plate or a circularly polarizing plate wherein a retardation plate is further laminated, one side of the polarizing plate comprising the polarizer and the transparent protective film is a viewing angle compensation film. Or a polarizing plate in which a brightness enhancement film is further laminated on the polarizing plate if it is composed of the polarizer and the transparent protective film described above.

  As the retardation plate, a λ plate (１ ／ λ plate or ４λ plate) capable of forming an elliptically polarized light or circularly polarized light composite polarizing plate used in an image display device for mobile use is formed on the protective film. And effectively used. The elliptically polarized light or circularly polarized light composite polarizing plate has a function of changing to an elliptically polarized light or circularly polarized light when the incident polarization direction is linearly polarized light, and to changing to a linearly polarized light when the incident polarization direction is elliptically or circularly polarized light. I have. In particular, as a retardation plate capable of changing elliptically polarized light or circularly polarized light to linearly polarized light and linearly polarized light to elliptically polarized light or circularly polarized light, a so-called １ ／ λ plate is used. The 1 / 2λ plate has a function of changing the direction of linearly polarized light.

  As a specific example of the retardation plate, a polymer selected from polycarbonate, polyvinyl alcohol, polystyrene, polymethyl methacrylate, polyolefin such as polypropylene, polyarylate, polyamide, polyolefin, polynorbornene, etc. A stretched film obtained by a stretching treatment is exemplified. Such a stretched film may be processed by an appropriate method such as uniaxial or biaxial. Further, a birefringent film in which the refractive index in the thickness direction of the film is controlled by applying a contraction force and / or a stretching force while adhering to the heat-shrinkable film may be used.

  The brightness enhancement film is used for the purpose of improving the brightness in a liquid crystal display device or the like, and as an example, anisotropy is generated in the reflectance by stacking a plurality of thin film films having different refractive index anisotropy from each other. And a cholesteric liquid crystal polymer oriented film and a circularly polarized light separation sheet having the oriented liquid crystal layer supported on a film substrate.

  In the present invention, it is preferable that the rear-side polarizing plate 50 is formed by laminating one or two or more optical layers having the above-mentioned other optical functions on the side far from the liquid crystal cell.

  The above-mentioned various optical layers are integrated with the polarizing plate using a pressure-sensitive adhesive or an adhesive, but the pressure-sensitive adhesive or the adhesive used therefor is not particularly limited, and an appropriate one is selected and used. do it. It is preferable to use a pressure-sensitive adhesive from the viewpoint of simplicity of the bonding operation and prevention of generation of optical distortion. The pressure-sensitive adhesive is not particularly limited, and for example, a pressure-sensitive adhesive having a base polymer of an acrylic polymer, a silicone polymer, polyester, polyurethane, polyether, or the like can be used. Above all, like acrylic adhesives, they have excellent optical transparency, maintain appropriate wettability and cohesive strength, have excellent adhesion to substrates, and have heat resistance, etc. It is preferable to select a material that does not cause a peeling problem such as floating or peeling in an environment.

  Further, the pressure-sensitive adhesive layer may contain fine particles for exhibiting light scattering properties as necessary, and fillers, pigments made of glass fibers, glass beads, resin beads, metal powder, other inorganic powders, and the like. And a coloring agent, an antioxidant, an ultraviolet absorber and the like. Examples of the ultraviolet absorber include salicylic acid ester compounds, benzophenone compounds, benzotriazole compounds, cyanoacrylate compounds, nickel complex compounds, and the like.

  A pressure-sensitive adhesive layer can be provided on the transparent protective film constituting the polarizing plate or on the optical layer provided on the polarizing plate in order to adhere to another member such as a liquid crystal cell. The pressure-sensitive adhesive layer can be formed of an appropriate pressure-sensitive adhesive, such as an acrylic resin, according to the related art. In particular, from the viewpoint of preventing peeling under a high temperature environment, deterioration of optical characteristics due to a difference in thermal expansion, prevention of warpage of a front panel integrated liquid crystal display panel, and formation of a high quality and excellent durability liquid crystal image device. It is preferable that the pressure-sensitive adhesive layer has excellent heat resistance. The pressure-sensitive adhesive layer may be provided on a necessary surface if necessary.For example, if a transparent protective film of a polarizing plate composed of a polarizer and a transparent protective film is referred to, one or both surfaces of the transparent protective film as necessary. May be provided with an adhesive layer. The pressure-sensitive adhesive layer may be made of any suitable material such as acrylic, silicone, polyester, polyurethane, polyether, and rubber.

  When the pressure-sensitive adhesive layer provided on the polarizing plate or the optical member is exposed on the surface, it is preferable to temporarily cover the pressure-sensitive adhesive layer with a separator until practical use of the pressure-sensitive adhesive layer for the purpose of preventing contamination and the like. The separator is formed by a method of providing a release coat with a suitable release agent such as a silicone-based or long-chain alkyl-based, fluorine-based or molybdenum sulfide on a suitable thin leaf according to the transparent protective film or the like as necessary. be able to.

In the above-described set of polarizing plates of the present invention, the angle formed by the short side of the liquid crystal cell and the absorption axis of the front-side polarizing plate 30 is usually within ± 45 degrees, preferably within ± 10 degrees. is there. The angle formed by the long side of the liquid crystal cell and the absorption axis of the rear-side polarizing plate is usually within ± 45 degrees, preferably within ± 10 degrees.
More preferably, the absorption axis of the front polarizing plate 30 is substantially parallel to the short side direction of the liquid crystal cell, and the absorption axis of the rear polarizing plate is substantially parallel to the long side direction of the liquid crystal cell.

  Next, the front panel integrated liquid crystal display panel according to the present invention will be described. The front panel-integrated liquid crystal display panel according to the present invention is obtained by bonding the front plate-integrated polarizing plate 40 and the rear-side polarizing plate 50 to a liquid crystal cell. An example of a preferred layer configuration in a liquid crystal display panel is shown in a schematic sectional view. Referring to FIG. 2, front-panel-integrated liquid crystal display panel 80 of the present invention includes front-panel-integrated polarizing plate 40 constituting the set of polarizing plates of FIG. The liquid crystal cell 60 is bonded to the rear side of the liquid crystal cell 60 via an adhesive.

  As the adhesive used for bonding the set of the liquid crystal cell 60 and the polarizing plate, an adhesive using an acrylic resin as a base polymer having excellent transparency, weather resistance, heat resistance and the like is preferable.

  The front panel-integrated liquid crystal display panel 80 of the present invention has an amount of warpage of 0.5 mm or less, preferably 0.3 mm or less in absolute value when heated at 85 ° C. for 240 hours. Therefore, warpage in a high-temperature environment is suppressed, and the front panel integrated liquid crystal display panel fits in the housing of the final product.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In the examples, percentages and parts representing contents or amounts used are by weight unless otherwise specified.

[Example 1]
(1) Production of Set of Polarizing Plate The front-side polarizing plate (polarizing plate 1) was produced as follows. First, a polyvinyl alcohol film having a thickness of 60 μm (average degree of polymerization: about 2,400, saponification degree: 99.9 mol% or more) was uniaxially stretched about 5 times by dry stretching, and further, while maintaining the tension state, 60 After immersion in pure water of 1 ° C. for 1 minute, it was immersed in an aqueous solution of iodine / potassium iodide / water having a weight ratio of 0.05 / 5/100 at 28 ° C. for 60 seconds. Thereafter, the substrate was immersed in an aqueous solution of potassium iodide / boric acid / water having a weight ratio of 8.5 / 8.5 / 100 at 72 ° C. for 300 seconds. Subsequently, the film was washed with pure water at 26 ° C. for 20 seconds and dried at 65 ° C. to obtain a 23 μm-thick polarizer having iodine adsorbed and oriented on a polyvinyl alcohol film. Next, on one side of this polarizer, 3 parts of a carboxyl group-modified polyvinyl alcohol [trade name “KL-318” obtained from Kuraray Co., Ltd.] was dissolved in 100 parts of water, and the aqueous solution of the water-soluble epoxy resin was dissolved in 100 parts of water. An epoxy-based adhesive to which 1.5 parts of a polyamide epoxy-based additive (trade name “SUMIREZ Resin 650 (30)” obtained from Taoka Chemical Industry Co., Ltd., aqueous solution with a solid content of 30%) was added was applied. Then, a 40 μm-thick triacetyl cellulose film (trade name “KC4UY” manufactured by Konica Minolta Opto Co., Ltd.) is attached as a transparent protective film, and the above-mentioned adhesive is used to attach a norbornene resin to the opposite side. (Zeon Corporation, trade name “ZEONOR”) that was not stretched.

  The back side polarizing plate (polarizing plate 2) was manufactured as follows. First, a 30 μm-thick polyvinyl alcohol film (average degree of polymerization: about 2,400, degree of saponification of 99.9 mol% or more) was uniaxially stretched about 5 times by dry stretching, and further, while maintaining the tension state, 60 times. After immersion in pure water of 1 ° C. for 1 minute, it was immersed in an aqueous solution of iodine / potassium iodide / water having a weight ratio of 0.05 / 5/100 at 28 ° C. for 60 seconds. Thereafter, the substrate was immersed in an aqueous solution of potassium iodide / boric acid / water having a weight ratio of 8.5 / 8.5 / 100 at 72 ° C. for 300 seconds. Subsequently, after washing with pure water at 26 ° C. for 20 seconds, it was dried at 65 ° C. to obtain a 11 μm thick polarizer having iodine adsorbed and oriented on a polyvinyl alcohol film. A transparent protective film was bonded to this polarizer in the same manner as for the front-side polarizing plate. Then, a 5 μm-thick adhesive material (trade name “# L2” manufactured by Lintec Co., Ltd.) is pasted on the TAC side, and a 26 μm-thick brightness enhancement film (trade name “Advanced Polarized Film, Version manufactured by 3M”) is bonded thereto. 3 ").

With respect to the front-side polarizing plate and the rear-side polarizing plate produced in the above (1), the dimensional change rate of the polarizing plate in a high-temperature environment was measured by the following method. First, each of the produced polarizing plates was cut into a square or a rectangle having a length direction of 30 mm to 50 mm and a width direction of 20 to 50 mm, and allowed to stand at 85 ° C. for 100 hours. Next, the dimension (L ₀ ) in the longitudinal direction (absorption axis direction) at the time of cutting and the dimension (L ₁ ) in the longitudinal direction after standing in a high-temperature environment are measured by a two-dimensional measuring device manufactured by Nikon Corporation. The measurement was performed using “NEXIV VMR-12072”, and the dimensional change rate (%) was obtained from the following equation. The results are shown in the column of "Dimensional change rate of polarizing plate" in Table 1.
Dimensional change rate = [(L ₀ −L ₁ ) / L ₀ ] × 100

(2) Production of front panel integrated liquid crystal display panel The set of polarizing plates produced in (1) was bonded to a liquid crystal cell to produce a front panel integrated liquid crystal display panel. After applying a 20 μm thick adhesive [trade name “P-3132” manufactured by Lintec Co.] to the surface of the polarizing plate prepared in (1) on the side of the norbornene resin “ZEONOR”, the front-side polarizing plate Is cut into a 5-inch size so that the absorption axis of the polarizer is parallel to the short side of the liquid crystal cell, and the rear polarizing plate is set so that the absorption axis of the polarizer is parallel to the long side of the liquid crystal cell. Into 5 inch sizes. Next, the cut polarizing plates are bonded to the liquid crystal cell on the side of the adhesive, respectively, and the ultraviolet curable optical elastic resin [trade name “Super View Resin” manufactured by Dexelias Co., Ltd.] is placed on the triacetyl cellulose film side of the front polarizing plate. Was applied, and a front plate (trade name “Gorilla” manufactured by Corning) having a Young's modulus of 70 GPa and a thickness of 0.55 mm was laminated thereon. Thereafter, ultraviolet rays were irradiated from the front panel side (“D bulb” manufactured by Fusion UV Systems, integrated light quantity: 1200 mJ / cm ² ) to produce a front panel integrated liquid crystal cell.

  With respect to the front panel integrated liquid crystal display panel produced in the above (2), the amount of warpage in a high temperature environment was measured by the following method. First, the front-panel-integrated liquid crystal display panel was allowed to stand for 240 hours in an environment of 85 ° C., and the front panel was turned upside down to measure the two-dimensional measuring device “NEXIV VMR-12072” manufactured by Nikon Corporation. Placed on a table. Next, focus on the surface of the measuring table, and use that as a reference, focus on the center of each of the four corners and four sides of the front panel-integrated liquid crystal display panel and the center of the surface of the front panel-integrated liquid crystal display panel. After measuring the distance from the focal point, the distance from the measuring table to the longest absolute value was taken as the amount of warpage. The measurement results are shown in the column of "Amount of warpage" in Table 1.

Example 2
(1) Preparation of a set of polarizing plates An aqueous solution of polyvinyl alcohol was applied on a base film and dried to prepare a laminated film as a raw material for manufacturing a polarizer. Here, a polypropylene film having a thickness of 110 μm and a melting point of 163 ° C. was used as the base film.
Next, acetoacetyl group-modified polyvinyl alcohol powder (trade name “Gosefimer Z-200” manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) having an average degree of polymerization of 1,100 and a saponification degree of 99.5 mol% was added at 95 ° C. In hot water to prepare a 3% concentration aqueous solution. A water-soluble polyamide epoxy resin (trade name “SUMIREZ Resin 650” manufactured by Taoka Chemical Industry Co., Ltd., aqueous solution having a solid content of 30%) as a cross-linking agent was added to this aqueous solution in an amount of 5 parts per 6 parts of solid content of polyvinyl alcohol. To obtain a coating liquid for a primer.
Then, after a corona treatment is applied to the base film made of polypropylene, a coating liquid for primer is applied to the corona-treated surface with a microgravure coater, and dried at 80 ° C. for 10 minutes to obtain a thickness of 0 mm. A primer layer of 0.2 μm was formed.
Next, polyvinyl alcohol powder (trade name “PVA124” obtained from Kuraray Co., Ltd.) having an average degree of polymerization of 2,400 and a degree of saponification of 98.0 to 99.0 mol% was dissolved in hot water at 95 ° C. An 8% aqueous solution of polyvinyl alcohol was prepared. The obtained aqueous solution is applied on the primer layer of the base film at room temperature using a lip coater and dried at 80 ° C. for 20 minutes to form a laminated film composed of the base film / primer layer / polyvinyl alcohol layer. Produced.
The resulting laminated film was stretched 5.8 times at the free end vertically at a temperature of 160 ° C. The total thickness of the laminated stretched film thus obtained was 28.5 μm, and the thickness of the polyvinyl alcohol layer was 5.0 μm.
The obtained laminated stretched film was immersed in an aqueous solution having a weight ratio of water / iodine / potassium iodide of 100 / 0.35 / 10 at 26 ° C. for 90 seconds to be dyed, and then washed with pure water at 10 ° C. Next, this laminated film was immersed in an aqueous solution having a weight ratio of water / boric acid / potassium iodide of 100 / 9.5 / 5 at 76 ° C. for 300 seconds to crosslink polyvinyl alcohol. Subsequently, the substrate was washed with pure water at 10 ° C. for 10 seconds, and finally dried at 80 ° C. for 200 seconds. By the above operation, a polarizing laminated film in which a polarizer comprising a polyvinyl alcohol layer in which iodine was adsorbed and oriented was formed on a polypropylene base film was produced.
Carboxyl group-modified polyvinyl alcohol [trade name "KL-318" obtained from Kuraray Co., Ltd.] on the surface (polarizer surface) opposite to the substrate film of the polarizing laminated film prepared above, with respect to 100 parts of water. Is dissolved in an aqueous solution thereof, and a polyamide-epoxy-based additive which is a water-soluble epoxy resin [trade name “SUMIREZ Resin 650 (30)” obtained from Taoka Chemical Industry Co., Ltd., aqueous solution having a solid content of 30%] Is applied, and a 25 μm-thick triacetyl cellulose film (TAC) (trade name “KC2UA” manufactured by Konica Minolta Opto Co., Ltd.) is attached as a transparent protective film. By peeling only the base film, a polarizing plate composed of TAC / polyvinyl alcohol-based polarizer / primer layer was obtained.
Next, an ultraviolet-curing adhesive containing an epoxy compound and a photocationic polymerization initiator is applied to the primer surface side, and a film (trade name “ZEONOR” manufactured by Zeon Corporation) that is not stretched with norbornene resin is applied. bonded combined, irradiating with ultraviolet rays from the norbornene resin side [Fusion UV systems, Inc. "D bulb" integrated light intensity 1200 mJ / cm ^2] was carried out, by curing the adhesive, TAC / polyvinyl alcohol-based polarizer / Primer layer / Norbornene resin polarizing plate (3) was obtained.
Then, a 5 μm-thick adhesive material (trade name “# L2” manufactured by Lintec Co., Ltd.) is pasted on the TAC side, and a 26 μm-thick brightness enhancement film (trade name “Advanced Polarized Film, Version manufactured by 3M”) is bonded thereto. 3 ").

With respect to the polarizing plate (3) produced above, the polarizing plate was cut into a square or rectangular shape having a length direction of 30 mm to 50 mm and a width direction of 20 to 50 mm. %).
The front polarizer is obtained by removing the adhesive on the TAC side of the polarizer (2) and the brightness enhancement film from the polarizer (2), and the adhesive is applied to the surface of the polarizer (3) on the norbornene resin “ZEONOR” side as the rear polarizer. A front panel integrated liquid crystal cell was prepared in the same manner as in Example 1 except that the agent was applied and bonded to the liquid crystal cell, and the amount of warpage in a high temperature environment was measured. The results are shown in the column of “Amount of warpage” in Table 1.

[Example 3]
As the front-side polarizing plate to be bonded to the liquid crystal cell, the back-side polarizing plate (having a polarizer thickness of 11 μm) used in Example 1 from which the TAC surface-side adhesive and the brightness enhancement film have been removed is used. A liquid crystal display panel integrated with a front panel was produced in the same manner as in Example 1 except for the fact that the liquid crystal panel was warped, and the amount of warpage in a high-temperature environment was measured. The results are shown in the column of “Amount of warpage” in Table 1.

[Example 4]
(1) Preparation of Polarizing Plate Set The front-side polarizing plate was prepared as follows. First, a 75 μm-thick polyvinyl alcohol film (average degree of polymerization: about 2,400, degree of saponification: 99.9 mol% or more) was uniaxially stretched about 5 times by dry stretching, and further, while maintaining the tension state, 60 times. After immersion in pure water of 1 ° C. for 1 minute, it was immersed in an aqueous solution of iodine / potassium iodide / water having a weight ratio of 0.05 / 5/100 at 28 ° C. for 60 seconds. Thereafter, the substrate was immersed in an aqueous solution of potassium iodide / boric acid / water having a weight ratio of 8.5 / 8.5 / 100 at 72 ° C. for 300 seconds. Subsequently, the substrate was washed with pure water at 26 ° C. for 20 seconds and dried at 65 ° C. to obtain a polarizer having a thickness of 28 μm in which iodine was adsorbed and oriented on a polyvinyl alcohol film. Next, on one side of this polarizer, 3 parts of a carboxyl group-modified polyvinyl alcohol [trade name “KL-318” obtained from Kuraray Co., Ltd.] was dissolved in 100 parts of water, and the aqueous solution of the water-soluble epoxy resin was dissolved in 100 parts of water. An epoxy-based adhesive to which 1.5 parts of a polyamide epoxy-based additive (trade name “SUMIREZ Resin 650 (30)” obtained from Taoka Chemical Industry Co., Ltd., aqueous solution with a solid content of 30%) was added was applied. Then, a 40 μm-thick triacetyl cellulose film (trade name “KC4UY” manufactured by Konica Minolta Opto Co., Ltd.) was attached as a transparent protective film to obtain a polarizing plate comprising a TAC / PVA layer.
Thereafter, with respect to the polarizing plate prepared above, the polarizing plate was cut into a square or rectangular size of 30 to 50 mm in the longitudinal direction and 20 to 50 mm in the width direction, and the dimensional change rate (% ).

The rear polarizing plate was prepared as follows. First, a polyvinyl alcohol aqueous solution was applied on a substrate film and dried to prepare a laminated film serving as a raw material for producing a polarizer. Here, a polypropylene film having a thickness of 110 μm and a melting point of 163 ° C. was used as the base film.
Next, acetoacetyl group-modified polyvinyl alcohol powder (trade name “Gosefimer Z-200” manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) having an average degree of polymerization of 1,100 and a saponification degree of 99.5 mol% was added at 95 ° C. In hot water to prepare a 3% concentration aqueous solution. A water-soluble polyamide epoxy resin (trade name “SUMIREZ Resin 650” manufactured by Taoka Chemical Industry Co., Ltd., aqueous solution having a solid content of 30%) as a cross-linking agent was added to this aqueous solution in an amount of 5 parts per 6 parts of solid content of polyvinyl alcohol. To obtain a coating liquid for a primer.
Then, after a corona treatment is applied to the base film made of polypropylene, a coating liquid for primer is applied to the corona-treated surface with a microgravure coater, and dried at 80 ° C. for 10 minutes to obtain a thickness of 0 mm. A primer layer of 0.2 μm was formed.
Next, polyvinyl alcohol powder (trade name “PVA124” obtained from Kuraray Co., Ltd.) having an average degree of polymerization of 2,400 and a degree of saponification of 98.0 to 99.0 mol% was dissolved in hot water at 95 ° C. An 8% aqueous solution of polyvinyl alcohol was prepared. The obtained aqueous solution is applied on the primer layer of the base film at room temperature using a lip coater and dried at 80 ° C. for 20 minutes to form a laminated film composed of the base film / primer layer / polyvinyl alcohol layer. Produced.
The resulting laminated film was stretched 5.8 times at the free end vertically at a temperature of 160 ° C. The total thickness of the laminated stretched film thus obtained was 28.5 μm, and the thickness of the polyvinyl alcohol layer was 5.0 μm.
The obtained laminated stretched film was immersed in an aqueous solution having a weight ratio of water / iodine / potassium iodide of 100 / 0.35 / 10 at 26 ° C. for 90 seconds to be dyed, and then washed with pure water at 10 ° C. Next, this laminated film was immersed in an aqueous solution having a weight ratio of water / boric acid / potassium iodide of 100 / 9.5 / 5 at 76 ° C. for 300 seconds to crosslink polyvinyl alcohol. Subsequently, the substrate was washed with pure water at 10 ° C. for 10 seconds, and finally dried at 80 ° C. for 200 seconds. By the above operation, a polarizing laminated film in which a polarizer composed of a polyvinyl alcohol layer in which iodine was adsorbed and oriented was formed on a polypropylene base film was produced.
Carboxyl group-modified polyvinyl alcohol [trade name "KL-318" obtained from Kuraray Co., Ltd.] on the surface (polarizer surface) opposite to the substrate film of the polarizing laminated film prepared above, with respect to 100 parts of water. Is dissolved in 3 parts thereof, and a polyamide-epoxy-based additive which is a water-soluble epoxy resin [trade name “SUMIREZ Resin 650 (30)” obtained from Taoka Chemical Industry Co., Ltd., aqueous solution having a solid content of 30%] is dissolved in the aqueous solution. Was applied, and a 25 μm-thick triacetyl cellulose film (TAC) [trade name “KC2UA” manufactured by Konica Minolta Opto Co., Ltd.] was laminated as a transparent protective film. By peeling only the base film, a polarizing plate composed of TAC / polyvinyl alcohol-based polarizer / primer layer was obtained. Thereafter, a 5 μm-thick adhesive material (trade name “# L2” manufactured by Lintec Co., Ltd.) is pasted on the TAC side, and a 26 μm-thick brightness enhancement film (trade name “Advanced Polarized Film, Version manufactured by 3M”) is bonded thereto. 3 ").
With respect to the polarizing plate prepared above, the polarizing plate was cut into a square or rectangular size having a length of 30 mm to 50 mm and a width of 20 to 50 mm, and the dimensional change rate (%) was determined in the same manner as in Example 1. I asked.
Then, a 20 μm-thick adhesive (trade name “P-3132” manufactured by Lintec Co., Ltd.) was directly applied to the surface of the polarizer without the transparent protective layer. A display panel was manufactured, and the amount of warpage under a high temperature environment was measured. The results are shown in the column of “Amount of warpage” in Table 1.

[Comparative Example 1]
Except that the front-side polarizing plate used in Example 1 (having a polarizer having a thickness of 23 μm) was used as the rear-side polarizing plate to be bonded to the liquid crystal cell, the front-plate integrated type was used in the same manner as in Example 1. A liquid crystal display panel was manufactured, and the amount of warpage under a high temperature environment was measured. The results are shown in the column of “Amount of warpage” in Table 1.

[Comparative Example 2]
As the front-side polarizing plate to be bonded to the liquid crystal cell, the back-side polarizing plate (having a polarizer thickness of 11 μm) used in Example 1 from which the adhesive on the TAC side and the brightness enhancement film were removed was used. The same procedure as in Example 1 was repeated except that the front polarizing plate (having a polarizer having a thickness of 23 μm) used in Example 1 was used as the rear polarizing plate to be bonded to the liquid crystal cell. A body type liquid crystal display panel was manufactured, and the amount of warpage in a high temperature environment was measured. The results are shown in the column of “Amount of warpage” in Table 1.

  As is clear from the results shown in Table 1, in Examples 1 to 4, the front panel integrated liquid crystal display panel had a dimension in the absorption axis direction when the polarizing plate on the front side of the liquid crystal cell was heated at 85 ° C. for 100 hours. The combination is such that the change rate is larger than the dimensional change rate in the absorption axis direction when the back-side polarizing plate is heated at 85 ° C. for 100 hours.

In Examples 1 to 4, in the front plate-integrated liquid crystal display panel, the dimensional change rate in the absorption axis direction when the polarizing plate on the front side of the liquid crystal cell was heated at 85 ° C. for 100 hours was 1.2% or more. The rear-side polarizing plate is a combination satisfying that the dimensional change in the absorption axis direction when heated at 85 ° C. for 100 hours is 1.1% or less. In Examples 1, 2 and 4, the polarizer constituting the front-side polarizing plate is thicker than the polarizer constituting the rear-side polarizing plate.
In Examples 1 to 4, it can be seen that the amount of warpage of the front panel integrated liquid crystal display panel after standing for 240 hours in a high-temperature environment is 0.5 mm or less in absolute value.

10: front panel,
20: adhesive or UV-curable resin,
30: front side polarizing plate,
35a, 35b: transparent protective film of front side polarizing plate,
37: Polarizer of front side polarizing plate,
40: front plate integrated polarizing plate,
50: rear polarizing plate,
55a, 55b: transparent protective film of rear-side polarizing plate,
57: Back-side polarizer polarizer,
60: liquid crystal cell,
80: front panel integrated liquid crystal display panel.

Claims (5)

Is arranged on a viewer side of the liquid crystal cell, a front plate integrated polarizing plate is stuck on the front side polarizing plate front plate through an ultraviolet curable resin or a pressure-sensitive adhesive, it is arranged on the rear side of the liquid crystal cell It is a set with a rear polarizing plate,
The front plate has a Young's modulus of 2 GPa or more,
When the front plate is arranged on the viewing side of the liquid crystal cell, the front plate integrated type polarizing plate is on the side farther from the liquid crystal cell than the front side polarizing plate,
The front-side polarizing plate has an absorption axis substantially parallel to the short side direction of the liquid crystal cell, and the back-side polarizing plate has an absorption axis substantially parallel to the long side direction of the liquid crystal cell,
Both the front side polarizing plate and the back side polarizing plate are formed with an adhesive layer for bonding to a liquid crystal cell,
The front-side polarizing plate and the rear-side polarizing plate both have a structure in which a transparent protective film is laminated on at least one surface of a polarizer made of a polyvinyl alcohol-based resin film, and the polarized light constituting the front-side polarizing plate The polarizer is thicker than the polarizer constituting the back-side polarizing plate,
The front-side polarizing plate has a dimensional change in the absorption axis direction of 1.2% or more and 3.0% or less when heated at 85 ° C. for 100 hours in a state where the polarizing plate is not bonded to the front plate.
A set of polarizing plates, wherein the back-side polarizing plate has a dimensional change in the absorption axis direction of 1.1% or less when heated at 85 ° C. for 100 hours. Both the front-side polarizing plate and the back-side polarizing plate have a structure in which a transparent protective film is laminated on both surfaces of a polarizer made of a polyvinyl alcohol-based resin film, and at least one polarizing plate is provided on the liquid crystal cell side. The set of polarizing plates according to claim 1, wherein the obtained transparent protective film has an in-plane retardation. 3. The set of polarizing plates according to claim 1, wherein the back-side polarizing plate has another optical film laminated on a side farther from the liquid crystal cell. 4. The set of polarizing plates according to any one of claims 1 to 3, wherein the thickness of a polarizer constituting the rear-side polarizing plate is 15 µm or less. A set of the polarizing plate according to any one of claims 1 to 4, and a liquid crystal cell,
On the viewing side of the liquid crystal cell, a front plate-integrated polarizing plate constituting the set of polarizing plates is adhered on the polarizing plate side, and a back side constituting the set of polarizing plates is provided on the back side of the liquid crystal cell. A polarizing plate is stuck,
A front panel-integrated liquid crystal display panel, wherein the amount of warpage when heated at 85 ° C. for 240 hours is 0.5 mm or less in absolute value.

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