TW201736880A - Polarizing plate set and liquid crystal panel - Google Patents

Abstract

The present invention provides a polarizing plate set capable of suppressing warpage of a liquid crystal panel in a high temperature environment, and a liquid crystal panel obtained by laminating the polarizing plate set to a liquid crystal cell. The present invention provides a polarizing plate set comprising a first polarizing plate disposed on a viewing side of a liquid crystal cell and a second polarizing plate disposed on a back side of the liquid crystal cell, wherein the second polarizing plate has a reflective polarizing member. Given that a curling force of the first polarizing plate is C1, and a curling force of the second polarizing plate is C2, a difference between the curling forces C2-C1 is from 0.4 to 1.0 gf.

Description

Polarizer group and liquid crystal panel

The present invention relates to a polarizing plate group for suppressing warpage of a liquid crystal panel in a high temperature environment, and a liquid crystal panel using the polarizing plate group.

In recent years, low-voltage, low-voltage operation, lightweight and thin liquid crystal displays have rapidly spread as information display devices such as mobile phones, mobile information terminals, computer screens, and televisions. With the development of liquid crystal technology, liquid crystal displays of various modes have been proposed, and the problems of liquid crystal displays such as reaction speed, contrast, and narrow viewing angle have been solved. Furthermore, with the spread of portable liquid crystal displays, thin and light liquid crystal panels are also required.

With the reduction in thickness of the liquid crystal panel, the polarizing plate bonded to the liquid crystal cell in a high-temperature environment is shrunk, and the liquid crystal panel is warped, and there is a problem that it cannot be accommodated in the casing of the final product.

In order to suppress the warpage of such a liquid crystal display panel, a method of suppressing warpage of the liquid crystal display panel by changing the thickness of the polarizing plate has been developed from the beginning, and the polarizing plate is disposed in the liquid crystal cell for viewing. The side and the side opposite to the viewing side of the liquid crystal cell (back side). For example, JP-A-2012-58429 (Patent Document 1) discloses that the thickness of a polarizing film (referred to as a polarizer in the present invention) of a polarizing plate disposed on the viewing side of a liquid crystal cell is set to be A method in which the polarizing film disposed on the back side of the liquid crystal cell is thinner, thereby suppressing warpage of the liquid crystal display panel.

Japanese Laid-Open Patent Publication No. 2013-37115 (Patent Document 2) discloses that a polarizing film (referred to as a polarizing member in the present invention) included in an optical layered body on the viewing side is disposed to be arranged and viewed. The side of the opposite side of the optical layered body has a polarizing film thickness of 5 μm or more, thereby suppressing the warpage of the liquid crystal panel. However, these methods can exert an effect on a liquid crystal cell having a large thickness (for example, 0.5 mm or more and further 0.7 mm or more), but warpage cannot be sufficiently suppressed for a thin liquid crystal cell.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2012-58429

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2013-37115

An object of the present invention is to provide a polarizing plate group capable of suppressing warpage of a liquid crystal panel in a high temperature environment, and a liquid crystal panel obtained by bonding the polarizing plate group to a liquid crystal cell.

[1] A polarizing plate group comprising: a first polarizing plate disposed on a viewing side of a liquid crystal cell; and a second polarizing plate disposed on a back side of the liquid crystal cell; wherein the second polarizing plate has a reflection In the polarizer, when the curling force of the first polarizing plate is C1 and the curling force of the second polarizing plate is C2, the difference C2 - C1 of the crimping force is 0.4 to 1.0 gf.

[2] The polarizing plate group according to the above aspect, wherein the first polarizing plate and the second polarizing plate each have a polarizing member including a polyvinyl alcohol resin film, and the polarizer has a thickness of 20 μm or less. .

[3] The polarizing plate group according to the above [2], wherein the polarizer of the first polarizing plate has a thickness of 10 μm or more, and the polarizing plate of the second polarizing plate has a thickness of 10 μm or less.

[4] The polarizing plate group according to [2], wherein the second polarizing plate has a protective film on one of the polarizers and a reflective polarizer on the other surface layer. .

[5] The polarizing plate group according to [4], wherein the protective film has a moisture permeability of 500 g/(m ² ‧24 hr) or less.

[6] The liquid crystal panel according to any one of [1] to [5] wherein the liquid crystal cell has a thickness of 0.4 mm or less.

According to the present invention, the warpage of the liquid crystal panel in a high temperature environment can be solved, and the housing of the final product can be obtained in a high temperature environment. LCD panel.

10‧‧‧1st polarizer

11‧‧‧2nd polarizer

20, 21‧‧‧ polarizer

30a, 30b, 31a, 31b‧‧‧ protective film

32, 33‧‧‧ adhesive layer

40‧‧‧Next layer

50‧‧‧Reflective polarizer

60‧‧‧Liquid layer

61‧‧‧Substrate

62‧‧‧Liquid Crystal Cell

70‧‧‧Polar plate

71‧‧‧100mm

72‧‧‧ absorption axis direction

73‧‧‧ Fixtures

74‧‧‧ force

Fig. 1 is a schematic cross-sectional view showing an example of a preferred layer configuration of a polarizing plate group of the present invention.

Fig. 2 is a schematic cross-sectional view showing an example of a preferred layer configuration of the polarizing plate group of the present invention.

Fig. 3 is a schematic view for explaining the definition of the crimping force in the present invention.

Fig. 4 is a schematic view showing an example of a reflection type polarizing member used in the present invention.

Fig. 5 is a schematic cross-sectional view showing an example of a liquid crystal panel of the present invention.

Hereinafter, the polarizing plate group of the present invention and the liquid crystal panel using the polarizing plate group will be described with reference to the drawings, but the present invention is not limited by the embodiments.

The polarizing plate group of the present invention comprises a first polarizing plate 10 disposed on the viewing side of the liquid crystal cell and a second polarizing plate 11 disposed on the back side of the liquid crystal cell. A preferred layer configuration of the first polarizing plate 10 and the second polarizing plate 11 of the present invention will be described with reference to Fig. 1 . In the first polarizing plate 10 in Fig. 1, the protective films 30a and 30b are bonded to both surfaces of the polarizer 20, respectively. It is also useful to form a surface treatment layer on the surface opposite to the bonding surface of the protective film 30a and the polarizing member 20. The second polarizing plate 11 preferably has a protective film on at least one side of the polarizing member 21, as shown in FIG. The protective films 31a and 31b are laminated on both sides of the light member, and the reflective polarizer 50 is further laminated via the adhesive layer 40. Further, as shown in FIG. 2, the protective film 31a is layered on one of the polarizers 21, but the reflective polarizer 50 is laminated directly on the polarizer 21 via the adhesive layer 31 without passing through the protective film 31b. It is better. The polarizing plates are bonded to the liquid crystal cell via the adhesive layers 32 and 33, respectively, to form a liquid crystal panel.

In the polarizing plate assembly of the present invention, when the crimping force of the first polarizing plate 10 is C1 and the crimping force of the second polarizing plate is C2, the difference in crimping force C2-C1 is 0.4 to 1.0 gf. Good is 0.5 to 0.9 gf. By having such a difference in the curling force, it is possible to suppress the warpage of the liquid crystal panel after the liquid crystal panel is left to stand in an environment of 85 ° C for 250 hours. In general, the smaller the difference in the curling force is, the smaller the warpage of the liquid crystal panel is. However, the inventors of the present invention have unexpectedly found that the difference in the curling force in the above range can effectively reduce the warpage of the liquid crystal panel.

In order to achieve the above difference in the curling force, the curling force C1 of the first polarizing plate is preferably from 0.2 to 1.0 gf, more preferably from 0.2 to 0.8 gf, still more preferably from 0.25 to 0.5 gf. Further, the curling force C2 of the second polarizing plate is preferably from 0.6 to 2.0 gf, more preferably from 0.6 to 1.8 gf, still more preferably from 0.65 to 1.5 gf.

In the present specification, the crimping force is defined as follows. As shown in Fig. 3, the polarizing plate is first cut out into a square of 100 mm square. At this time, each side of the polarizing plate 70 is inclined at 45 degrees with respect to the absorption axis direction 72 of the polarizing plate 70. Next, the cut polarizing plate 70 was left to stand in an environment of 85 ° C for 5 minutes for heat treatment to curl the polarizing plate 70. From the diagonal of the curled polarizing plate 70 with respect to the absorption axis direction 72, the half side is fixed by It has 73 and is fixed to the glass plate. Usually, since the polarizing plate is symmetrically curled, it is possible to fix which side. In this state, a force 74 is applied to the apex of the unfixed polarizing plate, and the force that causes the polarizing plate 70 to be flat is the curling force. Tapes and the like can be used for the fixture. The crimping force can be measured using, for example, an electronic balance.

Further, it is preferable to adopt an arrangement in which the absorption axis of the first polarizing plate is approximately parallel to the short-side direction of the liquid crystal cell, and the absorption axis of the second polarizing plate is approximately parallel to the longitudinal direction of the liquid crystal cell. . The term "about parallel" is not limited to being strictly parallel. For example, the angle between the absorption axis of the polarizing plate and each side of the liquid crystal cell is preferably 5 or less, more preferably 3 or less, and still more preferably 1 or less. .

In the present invention, it has been found that the liquid crystal panel warp is reduced by having a moderate difference in the curling force, and the principle is presumed to be due to the shape of a liquid crystal panel used in a smart phone or the like. In many cases, the first polarizing plate is disposed such that its absorption axis is approximately parallel to the short side of the liquid crystal cell, and the second polarizing plate is disposed such that its absorption axis is approximately parallel to the long side of the liquid crystal cell. Then, the curling force C1 of the first polarizing plate can be regarded as a force applied to a minute region of the long side of the liquid crystal cell, and the curling force C2 of the second polarizing plate can be regarded as a force applied to a minute region of the short side of the liquid crystal cell. In this way, the integration of the curling force C1 in the longitudinal direction of the liquid crystal cell is a force for warping the panel by the first polarizing plate, and the magnitude of the curling force C2 is integrated in the short-side direction of the liquid crystal cell. The force that becomes the second polarizer to warp the panel. It is presumed that the smaller the difference between the force of warping the liquid crystal cell by the first polarizing plate and the force of warping the liquid crystal cell by the second polarizing plate, the more the warpage can be suppressed. Therefore, It is presumed that it is advantageous to have a large curling force on the back side polarizing plate as compared with the viewing side polarizing plate in order to suppress the actual warpage of the liquid crystal panel. However, the above inference does not limit the invention in any way.

Hereinafter, components constituting the polarizing plate group and the liquid crystal panel of the present invention will be described in detail. In addition, the polarizer 20 included in the first polarizing plate 10 and the polarizer 21 included in the second polarizing plate 11 may be collectively referred to simply as a polarizer, and the protective film 30a, the protective film 30b, the protective film 31a, and The protective film 31b is sometimes collectively referred to simply as a protective film.

[Polarizer]

As the polarizers 20 and 21, any suitable one can be used as long as the above-described curling force is satisfied. The polarizer is usually produced by a step of uniaxially stretching a polyvinyl alcohol resin film, and dyeing the polyvinyl alcohol resin film with a dichroic dye to adsorb the dichroic dye. In the step, the polyvinyl alcohol-based resin film having the dichroic dye adsorbed thereon is treated with a boric acid aqueous solution to be crosslinked, and the step of cross-linking with a boric acid aqueous solution and then washing with water.

The polyvinyl alcohol-based resin can be produced by saponifying a polyvinyl acetate-based resin. The polyvinyl acetate-based resin may be a copolymer of vinyl acetate and other monomers copolymerizable therewith, in addition to polyvinyl acetate which is an oligomer of vinyl acetate. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group.

The degree of saponification of the polyvinyl alcohol-based resin is usually about 85. Up to 100% by mole, preferably 98% by mole or more. The polyvinyl alcohol-based resin may also be modified. For example, polyvinyl formal or polyvinyl acetal modified with an aldehyde may be used. The degree of polymerization of the polyvinyl alcohol-based resin is usually from about 1,000 to 10,000, preferably from about 1,500 to 5,000.

When such a polyvinyl alcohol-based resin is formed into a film, it is used as a green film of a polarizer. The method of forming a film of a polyvinyl alcohol-based resin is not particularly limited, and a film can be formed by a known method. The film thickness of the polyvinyl alcohol-based resin green film is, for example, about 10 to 100 μm, preferably about 10 to 50 μm.

The longitudinal uniaxial stretching of the polyvinyl alcohol-based resin film can be carried out before dyeing by a dichroic dye, simultaneously with dyeing, or after dyeing. When the longitudinal uniaxial extension is carried out after dyeing, the longitudinal uniaxial extension can be carried out before the boric acid treatment or in the boric acid treatment. Of course, the longitudinal uniaxial extension can also be performed in a plurality of stages as shown here. The vertical uniaxial stretching system may be a method of extending on a single axis between rolls having different circumferential speeds, or a method of extending on a single axis using a heat roll. Further, the longitudinal uniaxial stretching can be carried out by dry stretching extending in the atmosphere, or by wet stretching in which the polyvinyl alcohol-based resin film is swollen in a state in which a solvent such as water is swollen. The stretching ratio is usually about 3 to 8 times.

The dyeing by the dichroic dye of the polyvinyl alcohol-based resin film can be carried out, for example, by immersing the polyvinyl alcohol-based resin film in an aqueous solution containing a dichroic dye. In the case of a dichroic dye, iodine or a dichroic organic dye is specifically used. In addition, polyvinyl alcohol The resin film is preferably subjected to a treatment of immersing in water to swell it before the dyeing treatment.

When iodine is used as the dichroic dye, a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing iodine or potassium iodide for dyeing is usually employed.

The iodine content in the aqueous solution is usually about 0.01 to 1 part by weight with respect to 100 parts by weight of water, and the potassium iodide content is usually about 0.5 to 20 parts by weight with respect to 100 parts by weight of water. The temperature of the aqueous solution used for dyeing is usually about 20 to 40 °C. Further, the immersion time (dyeing time) in the aqueous solution is usually about 20 to 1,800 seconds.

On the other hand, when a dichroic organic dye is used as the dichroic dye, a method in which a polyvinyl alcohol-based resin film is immersed in an aqueous solution containing a water-soluble dichroic organic dye is usually used for dyeing. The content of the dichroic organic dye in the aqueous solution is usually about 1 × 10 ^-4 to 10 parts by weight, preferably 1 × 10 ^-3 to 1 part by weight, per 100 parts by weight of water. The aqueous dye solution may also contain an inorganic salt such as sodium sulfate as a dyeing aid. The temperature of the aqueous solution of the dichroic organic dye used for dyeing is usually about 20 to 80 °C. Further, the immersion time (dyeing time) in the aqueous solution is usually about 10 to 1,800 seconds.

The boric acid treatment after dyeing with a dichroic dye can be carried out by immersing the dyed polyvinyl alcohol resin film in an aqueous solution containing boric acid. The boric acid content in the aqueous solution containing boric acid is usually about 2 to 15 parts by weight, preferably 5 to 12 parts by weight, per 100 parts by weight of water. When iodine is used as the dichroic dye, the boric acid is contained. The aqueous solution preferably contains potassium iodide. The potassium iodide content in the aqueous solution containing boric acid is usually about 0.1 to 15 parts by weight, preferably 5 to 12 parts by weight, per 100 parts by weight of water. The immersion time in the aqueous solution containing boric acid is usually about 60 to 1,200 seconds, preferably 150 to 600 seconds, and more preferably 200 to 400 seconds. The temperature of the aqueous solution containing boric acid is usually 50 ° C or higher, preferably 50 to 85 ° C, and more preferably 60 to 80 ° C.

The polyvinyl alcohol-based resin film after boric acid treatment is usually washed with water. The water washing treatment can be carried out, for example, by immersing a boric acid-treated polyvinyl alcohol-based resin film in water. The temperature of the water in the water washing treatment is usually about 5 to 40 °C. Further, the immersion time is usually about 1 to 120 seconds.

After washing with water, drying treatment was carried out to obtain a polarizing member. The drying treatment can be carried out using a hot air dryer or a far infrared heater. The temperature of the drying treatment is usually about 30 to 100 ° C, preferably 50 to 80 ° C. The drying treatment time is usually about 60 to 600 seconds, preferably 120 to 600 seconds. By the drying treatment, the moisture content in the polarizer is lowered to a practical level. The moisture content is usually from about 5 to 20% by weight, preferably from 8 to 15% by weight. When the moisture content is less than 5% by weight, the flexibility of the polarizing member is lost, and it is damaged or broken after drying. Further, when the moisture content exceeds 20% by weight, thermal stability tends to be insufficient.

By operating as described above, a polarizer in which a dichroic dye is adsorbed and adsorbed on a polyvinyl alcohol-based resin film can be produced.

Furthermore, the stretching, dyeing, boric acid treatment, water washing step, drying step of the polyvinyl alcohol-based resin film in the manufacturing step of the polarizing member, This can be carried out according to the method described in, for example, Japanese Laid-Open Patent Publication No. 2012-159778. In the method described in this document, a method of forming a polyvinyl alcohol-based resin layer as a polarizer by applying a polyvinyl alcohol-based resin to a base film is also useful.

In order to adjust the difference in the curling force of the polarizing plate to the range of the present invention, it is preferable to set the thickness of the polarizer of the first polarizing plate and the second polarizing plate to 20 μm or less, and more preferably to Up to 15μm. In addition, it is preferable that the thickness of the polarizer of the first polarizing plate is 10 μm or more, and the thickness of the polarizer of the second polarizing plate is 10 μm or less. The thickness of the polarizer is usually 3 μm or more from the viewpoint of imparting good optical characteristics. Since the curling force of the polarizing plate is also affected by the contraction of the polarizing member and the reflective polarizing member, the thickness of the polarizing member is set to 20 μm or less, and the thickness of the polarizing member of the first polarizing plate is When the thickness of the polarizer of the second polarizing plate is set to a predetermined thickness difference, the difference in the curling force can be easily adjusted.

[protective film]

As the protective films 30a, 30b, 31a, 31b, those formed of a suitable transparent resin can be used. Specifically, it is preferred to use a polymer which is excellent in transparency, uniform optical characteristics, mechanical strength, thermal stability, and the like. As such a transparent resin film, for example, a cellulose film such as triethyl fluorenyl cellulose or diethyl fluorenyl cellulose, polyethylene terephthalate, polyethylene isophthalate, and polyparaphenylene can be used. A polyester film such as butylenedicarboxylate, an acrylic film such as poly(methyl) acrylate or poly(methyl) acrylate, a polycarbonate film, a polyether fluorene film, a polyfluorene film, and a poly Yttrium A film, a polyolefin film, a polynormene film, etc. are not limited by these.

The protective films 30a and 30b which are applied to the first polarizing plate 10 and the protective films 31a and 31b which are applied to the second polarizing plate 11 may be independently the same or different.

From the viewpoint of easily adjusting the difference in the curling force, the protective films 30a and 30b applied to the first polarizing plate 10 preferably have the same moisture permeability, and the difference in the moisture permeability is 40 ° C. The condition of 90% relative humidity is preferably 750 g/(m ² ‧24 hr) or less, more preferably 500 g/(m ² ‧24 hr) or less. The moisture permeability is a value measured in accordance with the cup method defined in JIS Z 0208. If the difference in the moisture permeability is to be the same degree, for example, when the protective films 30a and 30b are made of the same material, and one protective film is made of a material having a small moisture permeability, the other protective film is When a material having a large moisture permeability is used, a surface treatment layer (preferably a hard coat layer) is provided on the protective film having a large moisture permeability.

On the other hand, the protective films 31a and 31b applied to the second polarizing plate 11 preferably have different moisture permeability, and the difference in the moisture permeability is preferably 40 ° C and 90% relative humidity. 750 g / (m ² ‧ 24 hr) or more, more preferably 1000 g / (m ² ‧ 24 hr) or more. For example, by using different materials for the protective films 31a and 31b, the difference in moisture permeability can be increased. Further, it is preferable to omit the protective film 31b of the second polarizing plate and to have a protective film only on one side of the polarizing member. In this case, the moisture permeability of the protective film 31a is preferably 500 g/(m ² ‧24 hr). Hereinafter, it is more preferably 250 g/(m ² ‧24 hr) or less.

The protective film may be subjected to an easy subsequent treatment such as saponification treatment, corona treatment, primer treatment, anchor coating treatment, or the like on the bonding surface before bonding to the polarizing material. The thickness of the protective film is usually in the range of about 5 to 200 μm, preferably 10 μm or more, more preferably 80 μm or less, still more preferably 40 μm or less, and particularly preferably 35 μm or less.

Further, in order to impart desired surface optical characteristics or other characteristics, a coating layer (surface treatment layer) may be provided on the outer surface of the protective film 30a. Specific examples of the coating layer include a hard coat layer, an antiglare layer, an antireflection layer, an antistatic layer, and an antifouling layer. The method of forming the coating layer is not particularly limited, and a known method can be used.

When the liquid crystal cell is in an IPS (In-Plane Switching) mode, the phase difference between the protective film 30b and the protective film 31b in the thickness direction is not impaired by the wide viewing angle characteristic originally possessed by the IPS mode liquid crystal cell. The value Rth is preferably in the range of -10 to 10 nm. Further, the in-plane phase difference Re is also preferably in the range of -10 to 10 nm.

The phase difference Rth in the thickness direction is a value obtained by multiplying the value obtained by subtracting the refractive index in the thickness direction from the average refractive index in the plane by the thickness of the film, and is defined by the following formula (a). Further, the in-plane phase difference Re is a value obtained by multiplying the in-plane refractive index difference by the thickness of the film, and is defined by the following formula (b).

Rth=[(nx+ny)/2-nz]×d (a)

Re=(nx-ny)×d (b)

In the formula, the refractive index in the x-axis direction (in-plane slow axis direction) in the plane of the nx film, and the y-axis direction in the plane of the ny film (in-plane fast axis direction, The refractive index in the plane perpendicular to the x-axis, nz is the refractive index in the z-axis direction (thickness direction) perpendicular to the film surface, and then d is the thickness of the film.

Here, the phase difference value may be a value at any wavelength in the range of about 500 to 650 nm near the center of visible light, but in the present specification, the phase difference value at a wavelength of 590 nm is set as a standard. The phase difference Rth in the thickness direction and the phase difference Re in the plane can be measured using various commercially available phase difference meters.

In the method of controlling the phase difference Rth in the thickness direction of the protective film to be in the range of -10 to 10 nm, for example, a method of reducing the strain remaining in the in-plane and thickness directions at the time of film formation is exemplified. For example, a method in which the residual shrinkage strain in the in-plane and thickness direction generated when the cast resin solution is dried in the solvent casting method is alleviated by heat treatment can be employed. On the other hand, a method in which the resin film is extruded from the mold in the melt extrusion method and the case where it is extended during the period before the cooling is performed may be employed, so that the mold from the mold to the cooling cylinder is shortened as much as possible. The distance, and the method of controlling the amount of pressing and the rotation speed of the cooling cylinder so that the film is not extended. Further, similarly to the solvent casting method, a method of alleviating the strain remaining in the obtained film by heat treatment may be employed.

[Reflective polarizer 50]

The second polarizing plate 11 of the present invention has a reflective polarizer 50. Fig. 4 is a schematic cross-sectional view showing an example of a reflection type polarizing member used in the present invention. The reflective polarizer 50 is a multilayer laminate in which a layer A having birefringence and a layer B having substantially no birefringence are alternately laminated. For example, in In the illustrated example, the refractive index nx in the x-axis direction of the layer A is larger than the refractive index ny in the y-axis direction, and the refractive index nx in the x-axis direction of the layer B is substantially the same as the refractive index ny in the y-axis direction. Therefore, the refractive index difference between the A layer and the B layer is large in the x-axis direction and substantially zero in the y-axis direction. As a result, the x-axis direction becomes the reflection axis, and the y-axis direction becomes the transmission axis. The refractive index difference in the x-axis direction of the A layer and the B layer is preferably 0.2 to 0.3. Further, the x-axis direction corresponds to the extending direction of the reflective polarizer.

The above A layer is preferably composed of a material which exhibits birefringence by stretching. Representative examples of such materials include naphthalene dicarboxylic acid polyesters (for example, polyethylene naphthalate), polycarbonates, and acrylic resins (for example, polymethyl methacrylate). Preferred is polyethylene naphthalate. The above-mentioned layer B is preferably composed of a material which does not substantially exhibit birefringence even after being stretched. As a representative example of such a material, a copolyester such as naphthalene dicarboxylic acid and terephthalic acid can be cited.

The reflective polarizer is formed in the interface between the A layer and the B layer, and transmits light having a first polarization direction (for example, a p-wave) and a light having a second polarization direction perpendicular to the first polarization direction ( For example s wave) reflection. Among the reflected light, a part of the interface between the A layer and the B layer penetrates as light having the first polarization direction, and a part of the light is reflected as light having the second polarization direction. In the interior of the reflective polarizer, by performing such reflection and penetration a plurality of times, the light utilization efficiency can be improved.

Preferably, the reflective polarizer 50 includes a reflective layer R as the outermost layer on the opposite side to the polarizer 21. By providing the reflective layer R, the light that is finally unused and returned to the outermost portion of the reflective polarizer can be further By utilizing, the utilization efficiency of light can be further improved.

The reflective layer R is typically represented by a multilayer structure of a polyester resin layer to exhibit a reflective function.

The overall thickness of the reflective polarizer can be appropriately set depending on the purpose, the total number of layers included in the reflective polarizer, and the like. The overall thickness of the reflective polarizer is preferably from 15 μm to 50 μm, more preferably 30 μm or less, from the viewpoint of suppressing dimensional change in a high-temperature environment.

For the reflective polarizer, for example, those described in Japanese Laid-Open Patent Publication No. Hei 9-507308 can be used.

As the reflective polarizer 50, a commercially available product can be used as it is, or a commercially available product can be used for two times (for example, extension). Commercially available products include, for example, the trade name DBEF or APF manufactured by 3M Company.

[Finishing of polarizer and protective film]

The polarizer is bonded to the protective film and can be attached by an adhesive or an adhesive. The adhesive layer to which the polarizing member and the protective film are bonded may have a thickness of about 0.01 to 30 μm, preferably 0.01 to 10 μm, and more preferably 0.05 to 5 μm. When the thickness of the adhesive layer is in this range, no floating or peeling occurs between the laminated protective film and the polarizing member, and an adhesive force which is practically used without problems can be obtained. The adhesive layer to which the polarizing member and the protective film are bonded may have a thickness of about 5 to 50 μm, preferably 5 to 30 μm, and more preferably 10 to 25 μm.

When the polarizer and the protective film are followed, it is also useful to perform a saponification treatment, a corona treatment, a plasma treatment, or the like on the polarizer or the protective film in advance.

[adhesive agent]

As for the formation of the adhesive layer, an appropriate and suitable adhesive can be used depending on the kind or purpose of the object to be coated, and an anchor coating agent can be used as necessary. Examples of the subsequent agent include a solvent-based adhesive, an emulsion-type adhesive, a pressure-sensitive adhesive, a rewet adhesive, a polycondensation adhesive, a solventless adhesive, a film adhesive, and a hot melt adhesive. Wait.

One of the preferred adhesives is, for example, a water-based adhesive, and even if the adhesive component is dissolved or dispersed in water. An example of a component which can be dissolved in water is a polyvinyl alcohol-based resin. Further, in the case of an example of a water-dispersible binder component, there is a urethane resin having a hydrophilic group. The water-based adhesive can be prepared by mixing such an adhesive component with water, if necessary, in addition to an additional additive. In the case of a commercially available polyvinyl alcohol-based resin which can be used as a water-based adhesive, "KL-318" which is a carboxyl-modified polyvinyl alcohol sold by Kuraray Co., Ltd., etc. is mentioned.

The aqueous binder may contain a crosslinking agent as necessary. Examples of the crosslinking agent include an amine compound, an aldehyde compound, a methylol compound, a water-soluble epoxy resin, an isocyanate compound, a polyvalent metal salt, and the like. When a polyvinyl alcohol-based resin is used as the adhesive component, it is preferred to use an aldehyde compound typified by glyoxal, a methylol compound typified by methylol melamine, a water-soluble epoxy resin, or the like as a crosslinking. Agent.

Here, the water-soluble epoxy resin may be, for example, a polyamine epoxy resin obtained by reacting a polyamine polyamine with epichlorohydrin, such as diethylenetriamine or Polyethylene alkylamine, such as triamethylenetetramine, A reactant of a dicarboxylic acid such as an acid. In the case of a commercially available product of a water-soluble epoxy resin, "Sumirez Resin (registered trademark) 650 (30)", which is sold by Tiangang Chemical Industry Co., Ltd., etc., is available.

A water-based adhesive is applied to the adhesive surface of the polarizer and/or the protective film attached thereto, and the two are bonded together, followed by drying treatment, whereby a polarizing plate can be obtained. Before the next step, it is also useful to carry out the wettability in advance by performing the subsequent treatment such as saponification treatment, corona discharge treatment, plasma treatment, or primer treatment on the protective film. The drying temperature can be set, for example, to about 50 to 100 °C. After the drying treatment, the aging is carried out at a temperature slightly higher than room temperature, for example, at a temperature of about 30 to 50 ° C for about 1 to 10 days, preferably from the viewpoint of further improving the adhesion.

As another preferable adhesive, a curable adhesive composition which is hardened by irradiation with an active energy ray or heating can be mentioned. The curable adhesive composition may, for example, be a curable adhesive composition containing a radically polymerizable compound such as an acrylic compound or a curable adhesive composition containing a cationically polymerizable compound such as an epoxy-based compound. These compositions preferably each contain a radical polymerization initiator or a cationic polymerization initiator.

Further, the curable adhesive composition may contain other additives as long as the adhesion is not impaired, such as an ion trap, an antioxidant, a chain transfer agent, a sensitizer, an adhesion-imparting agent, a thermoplastic resin, and a filler. , flow regulators, plasticizers, defoamers, etc. The ion-trapping agent may, for example, be an inorganic compound containing a powdery lanthanoid, lanthanide, magnesium, aluminum, calcium, titanium, or the like, and the antioxidant may, for example, be hindered phenol. (Hindered phenol) is an antioxidant or the like.

Applying the curable adhesive composition to the back surface of the polarizer or the protective film or the bonding surfaces of the two, and then bonding them by the surface coated with the adhesive, by irradiating the active energy rays or heating The uncured adhesive layer is hardened, and the polarizer and the protective film are followed. As the coating method of the adhesive, various coating methods such as a doctor blade, a wire bar, a die coater, a comma coater, and a gravure coater can be employed.

The curable adhesive composition can be basically used as a solventless adhesive which does not substantially contain a solvent, and has the most suitable viscosity range in each coating method. Therefore, a solvent may be contained in order to adjust the viscosity. The solvent is preferably an organic solvent which does not reduce the optical properties of the polarizing member and which can dissolve the components represented by the epoxy compound well. For example, a hydrocarbon represented by toluene can be used, and ethyl acetate is used as a representative. Esters and the like.

When the adhesive composition is cured by irradiation with an active energy ray, the active energy ray system can use various types as described above, but it is preferably used from the viewpoint of easy handling and control of the amount of irradiation light or the like. Ultraviolet light. The irradiation intensity or the amount of irradiation of the active energy ray (for example, ultraviolet ray) is not affected by various optical properties represented by the degree of polarization of the polarizing member, and various optical properties typified by the transparency and phase difference characteristics of the protective film. Within the scope, it is appropriately determined in such a manner as to maintain moderate productivity.

[adhesive]

The adhesive may be excellent in optical transparency and excellent in adhesion properties such as moderate wettability, cohesiveness, and adhesion. It is preferably excellent in durability and the like. Specifically, the adhesive forming the adhesive layer is preferably an adhesive (acrylic adhesive) containing an acrylic resin.

The acrylic resin contained in the acrylic pressure-sensitive adhesive is, for example, a resin containing an alkyl acrylate such as butyl acrylate, ethyl acrylate, isooctyl acrylate or 2-ethylhexyl acrylate as a main monomer. This acrylic resin is usually copolymerized with a polar monomer. The polar single system refers to a compound having a polymerizable unsaturated bond and a polar functional group. Here, the polymerizable unsaturated bond is generally derived from a (meth) acrylonitrile group, and further, the polar functional group may be a carboxyl group. Hydroxy, amidino, amine, epoxy, and the like. Specific examples of the polar monomer include (meth)acrylic acid, 2-hydroxypropyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, and (meth)acrylamide, ( 2-N,N-dimethylaminoethyl methacrylate, glycidyl (meth) acrylate, and the like.

Further, in the acrylic pressure-sensitive adhesive, an acrylic resin and a crosslinking agent are usually blended together.

Representative examples of the crosslinking agent include an isocyanate compound having at least two isocyanato groups (-NCO) in the molecule.

In the adhesive, various additives can be further formulated. Preferred additives include, for example, a decane coupling agent, an antistatic agent, and the like. The decane coupling agent is effective in improving the adhesion to the glass. The antistatic agent is effective in reducing or preventing generation of static electricity.

The adhesive layer can be formed by dissolving the above-mentioned adhesive component in an organic solvent to prepare an adhesive composition, directly applying it onto a polarizing member or a protective film, and drying the solvent. Or the method of removing the adhesive composition; or applying the adhesive composition to the release treatment surface of the substrate film composed of the resin film subjected to the release treatment, and drying the solvent to form an adhesive layer. A method of attaching a protective film to a transparent protective film. When the adhesive layer is formed on the transparent protective film by the direct coating method of the former, a resin film (also referred to as a separator) which is subjected to release treatment is attached to the surface thereof for use. Temporarily protect the surface of the adhesive layer. From the viewpoint of the workability of the adhesive composition of the organic solvent solution, the latter transfer method is often employed, and in this case, the release-treated base film which is initially used in the formation of the adhesive layer is attached. It is also suitable for this feature when it is attached directly to the polarizing plate and becomes a separate piece.

It is also useful to perform corona treatment, plasma treatment, etc. on the polarizer surface, the protective film surface, and the adhesive surface before laminating the polarizer and the protective film.

[layer of other components]

An adhesive layer may be used for laminating the polarizing plate and the liquid crystal cell, and an adhesive or an adhesive may be used for the adhesive layer used in the laminate of the reflective polarizing member 50, and it is preferred that the bonding of either one is adhesive. Agent. The adhesive layer may be excellent in optical transparency and excellent in adhesion properties such as appropriate wettability, cohesiveness, and adhesion, and further preferably excellent in durability and the like. Specifically, the adhesive forming the adhesive layer is preferably an adhesive (acrylic adhesive) containing an acrylic resin.

As the adhesive layer, it can be used in the same manner as those used in the above-mentioned polarizer and protective film. Adhesive system can be used separately The same person can also use the same.

It is also useful to perform corona treatment, plasma treatment, etc. on the polarizer surface, the protective film surface, and the adhesive surface before laminating the adhesive on the polarizing plate. In addition, in the case of laminating the reflective polarizer, it is also useful to perform corona treatment, plasma treatment, or the like on the bonding surface and the adhesive surface of the reflective polarizer 50 in advance. The adhesive layer used for laminating the reflective polarizer 50 is preferably 25 μm or less. More preferably, it is 15 μm or less. Usually, the thickness of the adhesive layer is 3 μm or more.

[Liquid Crystal Cell, LCD Panel]

The liquid crystal cell system has two unit cell substrates and a liquid crystal layer sandwiched between the substrates. The cell substrate is generally made of glass, but it can also be a plastic substrate. Others, the liquid crystal cell itself used in the liquid crystal panel of the present invention can be constituted by various types employed in the field (for example, known as an IPS mode, a VA mode, or a TN mode as a driving mode). In recent years, the thickness of the liquid crystal cell is thinned, and the rigidity thereof is weakened, so that warpage is very likely to occur when a liquid crystal panel is produced. Therefore, the conventional polarizing plate group which can reduce the warpage of the liquid crystal panel can exert an effect on a liquid crystal cell having a large thickness (for example, 0.5 mm or more), but it is still produced when it is applied to a thin liquid crystal cell. The condition of the liquid crystal panel warping. However, in the case of the polarizing plate group of the present invention, even if the thickness of the liquid crystal cell is 0.4 mm or less, or even 0.3 mm or less, the warpage can be remarkably reduced. In the present invention, the thickness of the liquid crystal cell 62 includes the liquid crystal layer 60 and the thickness of one of the liquid crystal layers 60 to the substrate 61.

As shown in Figure 5, the invention is biased via an adhesive layer The light panel group is attached to the liquid crystal cell 62 to form a liquid crystal panel.

From the other viewpoints, the absolute value of the amount of warpage of the liquid crystal panel of the present invention when heated at 85 ° C for 250 hours is 0.5 mm or less, preferably 0.3 mm or less. By bonding the polarizing plate group of the present invention to a liquid crystal cell, the liquid crystal panel of the present invention is a panel-integrated liquid crystal display panel which is housed in a casing of a final product by suppressing warpage in a high-temperature environment.

The shape of the polarizing plate is preferably a rectangular shape having long sides and short sides from the viewpoint of making the effect of the present invention more remarkable. When the polarizing plate of the present invention has a rectangular shape having long sides and short sides, the length of the long side and the length of the short side are preferably from 10:1 to 1:1, more preferably from 2:1 to 1:1. Further, the length of the polarizing plate is preferably 50 mm or more, more preferably 150 mm or more, and the length of the short side is preferably 40 mm or more, more preferably 80 mm or more. Specifically, the size of the polarizing plate of the present invention is preferably 2.7 (55 mm × 41 mm) or more, preferably 11.3 (174 mm × 231 mm) or less.

[Examples]

Hereinafter, the present invention will be more specifically described by the examples, but the present invention is not limited by the examples. In the example, the "parts" and "%" indicating the content or the amount used are based on the weight unless otherwise specified. Further, the measurement of each physical property in the following examples was carried out by the following method.

(1) Determination of thickness:

The measurement was carried out using a digital micrometer "MH-15M" manufactured by Nikon Co., Ltd.

(2) Determination of curling force

As shown in Fig. 3, the polarizing plate was first cut into a square of 100 mm square, and at this time, each side of the polarizing plate was inclined by 45 degrees with respect to the absorption axis direction of the polarizing plate. Next, the cut polarizing plate was subjected to heat treatment for 5 minutes in an environment of 85 ° C to curl the polarizing plate 70. From the diagonal of the curled polarizing plate perpendicular to the absorption axis direction, the half side is fixed to the glass plate by tape. In this state, the pressure at which the apex of the polarizing plate that is not fixed is pressed against the electronic balance is applied, and the force that causes the polarizing plate to be flat is used as the curling force.

(3) Determination of warpage amount of liquid crystal panel

The amount of warpage of the produced liquid crystal panel in a high temperature environment was measured by the following method. First, the liquid crystal display panel was allowed to stand in an environment of 85 ° C for 250 hours, and then the first polarizing plate was placed on the upper side, and placed on a measuring table of a two-dimensional measuring device "NEXIV VMR-12072" manufactured by Nikon Co., Ltd. . Next, the focus is concentrated on the surface of the measurement stage, and the focus is concentrated on the four corners of the liquid crystal panel, the center of each of the four sides, and the center of the surface of the liquid crystal panel, and the distance from the reference focus is measured. Then, the longest distance from the distance from the measuring table to the absolute value is set as the amount of warpage, and the warp of the panel edge on the viewing side of the liquid crystal panel is set to be warped, and the edge of the panel on the back side is set. The warp of the tilt is set to negative warpage. The results are summarized in Table 1.

(4) Determination of moisture permeability of protective film

The moisture permeability was measured in accordance with the cup method specified in JIS Z 0208 under the conditions of a temperature of 40 ° C and a relative humidity of 90%.

[Example 1]

The viewing side polarizing plate was produced as follows. A polyvinyl alcohol film having a thickness of 30 μm (average degree of polymerization of about 2400, a degree of saponification of 99.9 mol% or more) was longitudinally uniaxially stretched by about 5 times by dry stretching, and then kept under tension and immersed at 60 ° C. After 1 minute of pure water, the aqueous solution was immersed in an iodine/potassium iodide/water weight ratio of 0.05/5/100 at 28 ° C for 60 seconds. Thereafter, an aqueous solution of 72 ° C in a weight ratio of potassium iodide/boric acid/water of 8.5/8.5/100 was immersed for 300 seconds. Then, it was washed with pure water at 26 ° C for 20 seconds, and then dried at 65 ° C to obtain a polarizer having a thickness of 12 μm in which iodine was adsorbed and adsorbed on the polyvinyl alcohol film.

Next, a water-based adhesive is applied to both sides of the polarizer, and the water-based adhesive is dissolved in a carboxyl group-modified polyvinyl alcohol (KL-318" manufactured by Kuraray Co., Ltd.) with respect to 100 parts by weight of water. A water-soluble polyamine epoxy resin [Sumirez Resin (registered trademark) 650 (30)" manufactured by Sumitomo Chemical Co., Ltd., a solid content concentration of 30% by weight] is compared with an aqueous solution of a polyvinyl alcohol aqueous solution. 100 parts by weight of water is mixed in a ratio of 1.5 parts by weight, and a thickness of 25 μm of triethyl fluorene-based cellulose film [KONICA MINOLTA Co., Ltd., trade name "KC2UA") is used as a protective film. A film of an acrylic hard coat layer of 7 μm and a decylene-based film (trade name “ZEONOR (registered trademark)” manufactured by Nippon Zeon Co., Ltd.) having a thickness of 23 μm which were not extended were bonded. The polarizing plate was dried at 80 ° C for 5 minutes, and aged at 40 ° C for 168 hours. Thereafter, a 20 μm thick adhesive [trade name "#KT" manufactured by LINTEC Co., Ltd.] was bonded to the decylene-based film side to obtain a viewing-side polarizing plate.

Under the conditions of a temperature of 40 ° C and a relative humidity of 90%, the film having an acrylic hard coat layer deposited on the triethylenesulfonated cellulose film has a moisture permeability of 450 g/(m ² ‧24 hr), and the decene-based film The moisture permeability is 6 g / (m ² ‧ 24 hr). The difference in moisture permeability is 444 g / (m ² ‧ 24 hr).

The back side polarizing plate was produced as follows. A polyvinyl alcohol film having a thickness of 20 μm (average degree of polymerization of about 2400, a degree of saponification of 99.9 mol% or more) was longitudinally uniaxially stretched by about five times by dry stretching, and then kept under tension and immersed at 60 ° C. After 1 minute of pure water, the aqueous solution was immersed in an iodine/potassium iodide/water weight ratio of 0.05/5/100 at 28 ° C for 60 seconds. Thereafter, it was immersed in an aqueous solution of 72 ° C in a weight ratio of potassium iodide/boric acid/water of 8.5/8.5/100. Then, it was washed with pure water at 26 ° C for 20 seconds, and then dried at 65 ° C to obtain a polarizer having a thickness of 7 μm in which iodine was adsorbed and adsorbed on the polyvinyl alcohol film.

The water-based adhesive was applied to one surface of the polarizing material, and a decene-based film having a thickness of 13 μm as a protective film [trade name "ZEONOR (registered trademark)" manufactured by ZEON Co., Ltd., Japan) was used at a wavelength of 590 nm. The in-plane phase difference value Re = 0.8 nm] is bonded. The polarizing plate was dried at 80 ° C for 5 minutes, and aged at 40 ° C for 168 hours. A 5 μm-thick adhesive (trade name “L2” manufactured by LINTEC Co., Ltd.) was attached to the other surface of the polarizer, and a 26 μm-thick brightness enhancement film (3M manufactured by Advanced Polarized Film) was bonded thereto. , Version 3"). Thereafter, a 20 μm-thick adhesive [trade name "#KT" manufactured by LINTEC Co., Ltd.] was attached to the decylene-based film side to obtain a back side polarizing plate. The moisture permeability of the decene-based film was 30 g/(m ² ‧24 hr) under the conditions of a temperature of 40 ° C and a relative humidity of 90%.

[Embodiment 2]

The viewing side polarizing plate was produced as follows. A polarizer having a thickness of 12 μm was produced in the same manner as in Example 1, and the water-based adhesive described in Example 1 was applied to both surfaces thereof, and a triethyl fluorene-based cellulose film having a thickness of 25 μm as a protective film was formed on one surface [KONICA MINOLTA OPTO The product name "KC2UA" manufactured by the company, and the triacetonitrile cellulose film [KONICA MINOLTA OPTO Co., Ltd. trade name "KC2CT W" manufactured by KONICA MINOLTA OPTO Co., Ltd., in-plane phase difference R0 at a wavelength of 590 nm] 1.2 nm, thickness direction phase difference Rth = 1.3 nm] was applied. The polarizing plate was dried at 80 ° C for 5 minutes, and aged at 40 ° C for 168 hours. Thereafter, a 20 μm-thick adhesive [trade name "#KT" manufactured by LINTEC Co., Ltd.] was attached to the triethylenesulfide cellulose film side having a thickness of 20 μm to obtain a viewing-side polarizing plate.

Under the conditions of a temperature of 40 ° C and a relative humidity of 90%, the moisture permeability of the above-mentioned 25 μm-thick triethylenesulfonated cellulose membrane is 1200 g/(m ² ‧24 hr), and the above-mentioned thickness of 20 μm of the triethylenesulfonated cellulose membrane is transparent. The humidity system was 1660 g/(m ² ‧24 hr). The difference in moisture permeability is 460 g / (m ² ‧ 24 hr).

As the back side polarizing plate, the back side polarizing plate used in Example 1 was used.

[Example 3]

The viewing side polarizing plate was produced as follows. A polarizer having a thickness of 7 μm was produced in the same manner as in Example 1, and the water-based adhesive described in Example 1 was applied to both surfaces thereof, and the thickness of the protective film was 25 μm on one surface. A triacetonitrile-based cellulose film [trade name "KC2UA" manufactured by KONICA MINOLTA OPTO Co., Ltd.] laminated with an acrylic hard coat film having a thickness of 7 μm and a triacetyl cellulose film having a thickness of 20 μm [KONICA MINOLTA The trade name "KC2CTW" manufactured by OPTO Co., Ltd. is bonded at an in-plane retardation value R0 = 1.2 nm at a wavelength of 590 nm and a thickness direction retardation value Rth = 1.3 nm. The polarizing plate was dried at 80 ° C for 5 minutes, and aged at 40 ° C for 168 hours. Thereafter, a 20 μm-thick adhesive [trade name "#KT" manufactured by LINTEC Co., Ltd.] was attached to the triethylenesulfide cellulose film side having a thickness of 20 μm to obtain a viewing-side polarizing plate.

Under the conditions of a temperature of 40 ° C and a relative humidity of 90%, the moisture permeability of the above-mentioned 25 μm-thick triethylenesulfonated cellulose membrane is 1200 g/(m ² ‧24 hr), and the above-mentioned thickness of 20 μm of the triethylenesulfonated cellulose membrane is transparent. The humidity system was 1660 g/(m ² ‧24 hr). The difference in moisture permeability is 460 g / (m ² ‧ 24 hr).

As the back side polarizing plate, the back side polarizing plate used in Example 1 was used.

[Comparative Example 1]

The viewing side polarizing plate was used, and the viewing side polarizing plate used in Example 2 was used.

The back side polarizing plate was produced as follows. A polarizer having a thickness of 12 μm was produced in the same manner as in Example 1, and the water-based adhesive described in Example 1 was applied to both surfaces thereof, and a triethyl fluorene-based cellulose film having a thickness of 25 μm as a protective film was formed on one surface [KONICA MINOLTA OPTO Co., Ltd. product name "KC2UA"], and unextendered 15μm thickness of decylene film [JSR Co., Ltd. "ARTON (registered trademark)" is bonded in the in-plane retardation value R0 = 0 nm at a wavelength of 590 nm and the thickness direction retardation value Rth = 0 nm]. The polarizing plate was dried at 80 ° C for 5 minutes, and aged at 40 ° C for 168 hours. A 5 μm-thick adhesive (trade name “L2” manufactured by LINTEC Co., Ltd.) was attached to the triethylenesulfonated cellulose film side, and a 26 μm-thick brightness enhancement film (trade name 3M) was attached thereto. Advanced Polarized Film, Version 3”). Thereafter, a 20 μm-thick adhesive [trade name "#KT" manufactured by LINTEC Co., Ltd.] was attached to the decylene-based film side to obtain a back side polarizing plate.

The moisture permeability of the triethylenesulfonated cellulose membrane is 1200 g/(m ² ‧24 hr) at a temperature of 40 ° C and a relative humidity of 90%, and the moisture permeability of the decylene-based membrane is 140 g / (m ² ‧ 24hr). The difference in moisture permeability is 1060 g/(m ² ‧24 hr).

[Comparative Example 2]

The viewing side polarizing plate was used, and the viewing side polarizing plate used in Example 1 was used.

The polarizing plate of the back side polarizing plate was produced as follows. First, a polyvinyl alcohol film having a thickness of 60 μm (average degree of polymerization of about 2,400, a degree of saponification of 99.9 mol% or more) was uniaxially stretched by about 5 times by dry stretching, and then kept under tension and immersed at 60 ° C. After 1 minute of pure water, it was immersed in an aqueous solution of iodine/potassium iodide/water in a weight ratio of 0.05/5/100 at 28 ° C for 60 seconds. Thereafter, the aqueous solution of potassium iodide/boric acid/water in a weight ratio of 8.5/8.5/100 was immersed at 72 ° C for 300 seconds. Then, it is washed with pure water at 26 ° C, and then dried at 65 ° C to obtain iodine adsorbed and aligned in the polyvinyl alcohol film. A polarizing member having a thickness of 23 μm.

Next, the water-based adhesive described in Example 1 was applied to both surfaces of the polarizer of 23 μm, and a triacetonitrile-based cellulose film (manufactured by KONICA MINOLTA OPTO Co., Ltd.) having a thickness of 40 μm as a protective film was used. KC4UY"], and a 23 μm-thickness-reducing decene-based film [trade name "ZEONOR (registered trademark)" manufactured by ZEON Co., Ltd., Japan) was bonded. The polarizing plate was dried at 80 ° C for 5 minutes, and aged at 40 ° C for 168 hours. A 5 μm-thick adhesive (trade name “L2” manufactured by LINTEC Co., Ltd.) was attached to the triethylenesulfonated cellulose film side, and a 26 μm-thick brightness enhancement film was bonded thereto. Polarized Film, Version 3”). Thereafter, a 20 μm-thick adhesive [trade name "#KT" manufactured by LINTEC Co., Ltd.] was attached to the decylene-based film side to obtain a back side polarizing plate.

Under the conditions of a temperature of 40 ° C and a relative humidity of 90%, the moisture permeability of the triacetyl cellulose membrane is 830 g / (m ² ‧ ²⁴ hr), and the moisture permeability of the decene-based membrane is 6 g / (m ² ‧ 24hr). The difference in moisture permeability was 824 g/(m ² ‧24 hr).

[Comparative Example 3]

The viewing side polarizing plate was used, and the viewing side polarizing plate used in Example 2 was used.

The back side polarizing plate used in Comparative Example 1 was used for the back side polarizing plate.

[Production of LCD panel]

Using the above-described Examples 1 to 3 and Comparative Examples 1 to 3 In the polarizing plate group, a liquid crystal panel was produced as follows. First, the viewing side polarizing plate is cut to a diagonal of 7 相对 with respect to the short side of the liquid crystal cell so that the absorption axis is parallel, and the rear side polarizing plate is opposed to the long side of the liquid crystal cell so that the absorption axis is Cut in a parallel manner to a diagonal size of 7 inches. Next, one of the pair of polarizing plates is cut by the adhesive layer so that the short sides of the two polarizing plates are aligned with the short sides of the liquid crystal cell in parallel with the liquid crystal cell. The thickness of the liquid crystal cell used was 0.4 mm.

The above results are shown in Table 1.

[Industrial availability]

According to the present invention, it is useful to solve the warpage of the liquid crystal panel in a high-temperature environment and to obtain a liquid crystal panel housed in a casing of the final product in a high-temperature environment.

70‧‧‧Polar plate

71‧‧‧100mm

72‧‧‧ absorption axis direction

73‧‧‧ Fixtures

74‧‧‧ force

Claims (6)

A polarizing plate group includes: a first polarizing plate disposed on a viewing side of the liquid crystal cell; and a second polarizing plate disposed on a back side of the liquid crystal cell; wherein the second polarizing plate has a reflective polarizing member When the curling force of the first polarizing plate is C1 and the curling force of the second polarizing plate is C2, the difference C2 - C1 of the crimping force is 0.4 to 1.0 gf. The polarizing plate group according to the first aspect of the invention, wherein the first polarizing plate and the second polarizing plate each have a polarizing member including a polyvinyl alcohol resin film, and the polarizer has a thickness of 20 μm or less. The polarizing plate set according to the second aspect of the invention, wherein the first polarizing plate has a polarizer having a thickness of 10 μm or more, and the second polarizing plate has a polarizer having a thickness of 10 μm or less. The polarizing plate group according to claim 2, wherein the second polarizing plate has a protective film on one of the polarizers and a reflective polarizer on the other surface layer. The polarizing plate group according to Item 4, wherein the protective film has a moisture permeability of 500 g/(m ² ‧24 hr). A liquid crystal panel comprising the polarizing plate group and the liquid crystal cell according to any one of claims 1 to 5, wherein the liquid crystal cell has a thickness of 0.4 mm or less.