JP5098593B2 - Elliptical polarizing plate and liquid crystal display device - Google Patents

Description

  The present invention can form a thin liquid crystal display device having good visibility, and when bonded to a liquid crystal cell glass, the liquid crystal display device is likely to be caused by foreign matter, mainly due to heat from the backlight. The present invention relates to an elliptically polarizing plate with reduced edge wrinkles that are likely to occur due to contraction of the polarizing plate. The present invention also relates to a liquid crystal display device to which the elliptically polarizing plate is applied.

  Conventionally, a liquid crystalline optical compensator comprising an optically anisotropic layer in which a liquid crystal polymer is tilted and aligned has been known. For example, Japanese Patent Application Laid-Open No. 10-206637 (Patent Document 1) discloses a nematic hybrid alignment in which a liquid crystalline polymer exhibiting positive uniaxiality changes its inclination angle continuously from one surface to the other surface of a film. An optical element film is disclosed. Further, it is also known that the support is peeled off from the liquid crystalline polymer layer formed on the support, and a layer consisting essentially of the liquid crystalline polymer is used as an optical compensator. In 278491 (Patent Document 2), a film-like layer made of a liquid crystalline polymer formed on an alignment substrate is adhered to a releasable substrate with an adhesive, and then the alignment substrate is peeled off. It is disclosed that the liquid crystalline polymer film-like layer is transferred to a removable substrate, and then the removable substrate is peeled off.

  Further, in Japanese Patent Application Laid-Open No. 2004-226757 (Patent Document 3), a liquid crystal material layer formed on an alignment substrate and having a fixed liquid crystal alignment is adhered to a releasable substrate via an adhesive layer. Thereafter, the alignment substrate is peeled off, and the liquid crystal material layer is transferred to the releasable substrate to form a laminate comprising the releasable substrate / adhesive layer / liquid crystal material layer, and a polymer stretched film and a linear polarizing plate are separately provided. A laminate comprising a linearly polarizing plate / adhesive layer / stretched polymer film is laminated, and the releasable substrate is peeled off from the former laminate before or after the two laminates are laminated. Thus, it is disclosed that an optical laminate is formed by laminating a linearly polarizing plate, a polymer stretched film (retardation plate), and a liquid crystal material layer.

  As disclosed in Patent Document 3, an optical compensator having substantially no liquid crystal alignment layer and having no support is bonded to a linearly polarizing plate and a retardation plate to form an elliptically polarizing plate. It was expected to be a liquid crystal display device showing good visibility with a wide viewing angle by adhering to a liquid crystal cell via an adhesive. However, when such an elliptically polarizing plate is bonded to a liquid crystal cell, if there is even a small amount of foreign matter such as glass dust on the cell glass, the crack originated from the foreign matter in a thermal shock test that repeats a low temperature environment and a high temperature environment. It was a problem to produce. Glass debris may be generated during the process of etching and thinning glass. At present, when the panel is becoming thinner, such etching is an unavoidable process. Even when present, it is necessary to show durability.

  Further, in such an elliptically polarizing plate, the linearly polarizing plate, the retardation plate, and the optical compensation plate exhibit different thermal shrinkage rates. The problem is that it tends to occur. When the elliptically polarizing plate is used as a module, the linearly polarizing plate is easily contracted by receiving heat from a backlight serving as a light source or a semiconductor element serving as a driving source. Therefore, in order to effectively use the display area of the elliptically polarizing plate, it is also necessary that such wrinkles do not easily occur.

Japanese Patent Laid-Open No. 10-206637 JP-A-8-278491 JP 2004-226757 A

  Therefore, an object of the present invention is to provide an elliptically polarizing plate having an optical compensator made of a liquid crystal layer, which is thin and hardly causes cracks due to foreign matters in a thermal shock test, and applies it to a liquid crystal display device. There is. Another object of the present invention is to provide an elliptically polarizing plate that suppresses generation of wrinkles due to shrinkage of a linearly polarizing plate in a heat test, and to apply it to a liquid crystal display device.

  The present inventors have intensively studied in order to overcome the above-mentioned crack problem, and have found that the crack is generated by the optical compensator made of a liquid crystal layer following the expansion of the linear polarizing plate. . In the elliptically polarizing plate in which the linear polarizing plate, the first adhesive layer, the retardation plate, the second adhesive layer, the optical compensation plate composed of the liquid crystal layer, and the third adhesive layer are laminated in this order, the retardation plate The second adhesive layer that bonds the optical compensation plate and the optical compensation plate is disposed outside the optical compensation plate and has a higher storage elastic modulus than the third adhesive layer to be bonded to the liquid crystal cell glass, that is, a hard one It was found that the above-described cracks can be effectively prevented by comprising.

  In addition, the present inventors have also investigated that the soot when the heat resistance test as described above is performed occurs by the following mechanism. That is, when the linear polarizing plate is thermally shrunk, the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer follow the contracted linear polarizing plate and are composed of a phase difference plate or a liquid crystal layer having a thermal contraction rate smaller than that of the linear polarizing plate. Wrinkles are generated by distorting the optical compensator or both. In the elliptically polarizing plate in which the linear polarizing plate, the first adhesive layer, the retardation plate, the second adhesive layer, the optical compensation plate composed of the liquid crystal layer, and the third adhesive layer are laminated in this order, the linear polarizing plate The first pressure-sensitive adhesive layer that bonds the phase difference plate and the second pressure-sensitive adhesive layer that bonds the phase difference plate and the optical compensation plate are disposed outside the optical compensation plate and bonded to the liquid crystal cell glass. It is also possible to suppress the distortion of the retardation plate and the liquid crystal layer and to effectively prevent the occurrence of wrinkles as described above by configuring the third adhesive layer with a storage modulus higher than that of the third adhesive layer, that is, a hard one. I found it.

  The present invention has been completed based on the above findings and further various studies.

  That is, according to the present invention, the linear polarizing plate, the first adhesive layer, the retardation plate, the second adhesive layer, the optical compensation plate composed of the liquid crystal layer, and the third adhesive layer are laminated in this order, The second adhesive layer is provided with an elliptically polarizing plate having a storage elastic modulus larger than that of the third adhesive layer.

In this elliptically polarizing plate, it is preferable that the optical compensation plate does not have a support and is substantially composed of only a liquid crystal alignment layer. The second adhesive layer has a storage elastic modulus of 1 × 10 ⁵ N / m ² or more, and the third adhesive layer has a storage elastic modulus of 3 × 10 ⁴ N / m ² or less. It is preferable to do this.

Furthermore, in the above-mentioned elliptically polarizing plate, the first adhesive layer is preferably composed of a material having a storage elastic modulus larger than that of the third adhesive layer. Thus, when the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer are both made of a material having a storage elastic modulus larger than that of the third pressure-sensitive adhesive layer, the end portion is subjected to the heat resistance test as described above. It is possible to effectively prevent wrinkles that occur easily. In this case, both the first adhesive layer and the second adhesive layer have a storage elastic modulus of 1 × 10 ⁵ N / m ² or more, and the third adhesive layer has a storage elastic modulus of 3 × 10 ^4. N / m ² or less is preferable.

  Furthermore, according to the present invention, there is also provided a liquid crystal display device in which any one of the above-mentioned elliptical polarizing plates is attached to at least one surface of the liquid crystal cell on the third adhesive layer side.

  The elliptically polarizing plate of the present invention is thin and, when bonded to the liquid crystal cell glass through the third adhesive layer, cracks due to foreign substances are not easily generated. This is because the storage elastic modulus of the second pressure-sensitive adhesive layer that bonds the retardation plate and the optical compensation plate and the third pressure-sensitive adhesive layer provided outside the optical compensation plate is controlled. Further, by controlling the storage elastic modulus of the first pressure-sensitive adhesive layer that bonds the linearly polarizing plate and the retardation plate, generation of wrinkles due to thermal contraction of the linearly polarizing plate can be effectively prevented.

The prevention of cracks according to the present invention is considered to be due to the prevention of the transmission of the expansion of the linear polarizing plate. For example, the second adhesive layer is composed of one having a storage elastic modulus of 1 × 10 ⁵ N / m ² or more, and the third adhesive layer is composed of one having a storage elastic modulus of 3 × 10 ⁴ N / m ² or less. In this case, it is considered that the action of controlling the transmission of the expansion stress of the linear polarizing plate works more effectively.

Further, it is considered that the prevention of wrinkles according to the present invention is due to the prevention of the thermal contraction of the linear polarizing plate. For example, the first adhesive layer and the second adhesive layer are composed of those having a storage elastic modulus of 1 × 10 ⁵ N / m ² or more, and the third adhesive layer has a storage elastic modulus of 3 × 10 ⁴ N / m. If it is composed of ² or less, it is considered that the effect of controlling the transmission of heat shrinkage of the linearly polarizing plate works more effectively.

  Hereinafter, the present invention will be described in detail. The elliptically polarizing plate according to the present invention comprises a linear polarizing plate, a first adhesive layer, a retardation plate, a second adhesive layer, an optical compensation plate comprising a liquid crystal layer, and a third adhesive layer laminated in this order. is there. And the second adhesive layer is composed of one having a storage elastic modulus larger than that of the third adhesive layer, or both the first adhesive layer and the second adhesive layer are more than the third adhesive layer. Is also composed of a material having a large storage elastic modulus. An example of the elliptically polarizing plate according to the present invention is shown in a schematic sectional view in FIG. In this example, a retardation plate 2 is laminated on one side of a linear polarizing plate 1 via a first adhesive layer 5, and optical compensation is performed on the opposite side of the retardation plate 2 via a second adhesive layer 6. The plate 3 is laminated, and the third pressure-sensitive adhesive layer 7 is provided on the exposed surface of the optical compensation plate 3 to constitute an elliptically polarizing plate 10. A separator 20 that temporarily protects the adhesive layer until it is bonded to the liquid crystal cell is provided on the outside of the third adhesive layer 7 as necessary.

  The linearly polarizing plate 1 has a function of extracting linearly polarized light from incident light, and the type thereof is not particularly limited. An example of a suitable linearly polarizing plate includes a polarizing film having a dichroic dye adsorbed and oriented on a polyvinyl alcohol resin as a constituent element. Examples of the polyvinyl alcohol-based resin include polyvinyl alcohol, which is a saponified product of vinyl acetate, partially formalized polyvinyl alcohol, and a saponified product of an ethylene / vinyl acetate copolymer. As the dichroic pigment, iodine or a dichroic organic dye is used. A polyene oriented film such as a dehydrated polyvinyl alcohol product or a dehydrochlorinated polyvinyl chloride product can also be a polarizing film. Although the thickness of a polarizing film is about 5-80 micrometers normally, it is not limited to this.

  The linearly polarizing plate 1 may be one in which a transparent protective layer is provided on one side or both sides of a polarizing film. The transparent protective layer can be formed by an appropriate method such as a method of laminating a film or a method of applying a coating liquid. A preferred transparent protective layer is excellent in transparency, mechanical strength, thermal stability, moisture shielding property, isotropy and the like. Examples thereof include plastic films made of polyolefin, cyclic polyolefin, polyester, polycarbonate, polyamide, polyimide, polyethersulfone, polysulfone, polystyrene, acrylic resin, cellulose acetate resin such as triacetyl cellulose, and acrylic films. Examples thereof include a coating layer of a thermosetting type or ultraviolet curable resin such as urethane type, acrylic urethane type, epoxy type, and silicone type. Even if it has a transparent protective layer on one side or both sides, the thickness of the linearly polarizing plate 1 is usually about 30 to 200 μm.

  The retardation plate 2 is usually composed of a stretched resin film. Examples of the resin constituting the retardation plate 2 include polycarbonate, polyarylate, polyester such as polyethylene terephthalate and polyethylene naphthalate, polysulfone, olefin resin, cyclic polyolefin resin, styrene resin, and cellulose such as triacetyl cellulose. Examples thereof include acetate resins, and those obtained by mixing two or more of these resins. The thickness of the phase difference plate 2 is usually about 10 to 200 μm.

  On the other hand, the optical compensation plate 3 is preferably composed of a liquid crystal layer, in which the alignment state of the liquid crystal is fixed and there is no support. An optical compensator having a liquid crystal alignment layer is usually produced by applying a liquid crystalline compound on a support substrate, but the support substrate is peeled off before adhering to the retardation plate 2 to form an elliptically polarizing plate. Therefore, it is preferable to use it finally as a form without a support substrate. The thickness of the optical compensation plate 3 is, for example, about 0.1 to 30 μm, preferably about 0.5 to 25 μm, and more preferably about 3 to 20 μm. The optical compensation plate 3 has an optical function for compensating the viewing angle and color of the liquid crystal display device. An optical compensator composed of such a liquid crystal layer (a state in which a liquid crystal layer is formed on a support substrate) is, for example, a film sold by Shin Nippon Oil Co., Ltd. There is an “NH film” (trade name), etc., in which the nematic liquid crystal is fixed in an obliquely oriented state while changing its inclination in the film thickness direction.

  The first pressure-sensitive adhesive layer 5 that bonds the linearly polarizing plate 1 and the phase difference plate 2, the second pressure-sensitive adhesive layer 6 that bonds the phase difference plate 2 and the optical compensation plate 3, and the outside of the optical compensation plate 3 are provided. As the third pressure-sensitive adhesive layer 7, for example, an appropriate pressure-sensitive adhesive such as acrylic, silicone, polyester, polyurethane, polyamide, polyether, or rubber can be used. Among these, an acrylic pressure-sensitive adhesive is preferable from the viewpoints of optical transparency, adhesive properties, weather resistance, and the like.

  Formation of first adhesive layer 5 on linear polarizing plate 1 or retardation plate 2, formation of second adhesive layer 6 on retardation plate 2, and formation of third adhesive layer 7 on optical compensation plate 3 Is, for example, a method in which a solution or a melt of an adhesive is directly laid on a predetermined surface of the linearly polarizing plate 1, the phase difference plate 2 or the optical compensation plate 3 by an appropriate development method such as a casting method or a coating method, In accordance with this, an adhesive layer is formed on the separator, which is adhered to a predetermined surface of the linearly polarizing plate 1, the retardation plate 2 or the optical compensation plate 3, and the separator is peeled off as necessary. it can. The thickness of the pressure-sensitive adhesive layer can be appropriately determined according to the adhesive force and the like, but is generally in the range of about 3 to 100 μm, preferably in the range of about 5 to 50 μm.

One object of the present invention is to control the expansion stress generated in the linear polarizing plate 1 or the retardation plate 2 from being transmitted to the optical compensation plate 3 and to prevent the optical compensation plate 3 from cracking. Therefore, the second pressure-sensitive adhesive layer 6 that bonds the retardation plate 2 and the optical compensation plate 3 has a larger storage elastic modulus than the third pressure-sensitive adhesive layer 7 provided outside the optical compensation plate 3. To do. In particular, the second adhesive layer 6 has a storage elastic modulus of 1 × 10 ⁵ N / m ² or more, and the third adhesive layer 7 has a storage elastic modulus of 3 × 10 ⁴ N / m ² or less. It is advantageous to form such that

Further, the present invention controls that thermal contraction of the linear polarizing plate 1 is transmitted to the phase difference plate 2 or the optical compensation plate 3 and prevents wrinkles from being generated on the phase difference plate 2 and the optical compensation plate 3. For this purpose, a first pressure-sensitive adhesive layer 5 for bonding the linearly polarizing plate 1 and the phase difference plate 2 and a second pressure-sensitive adhesive layer 6 for bonding the phase difference plate 2 and the optical compensation plate 3 are used. Are both made of a material having a larger storage elastic modulus than the third adhesive layer 7 provided outside the optical compensation plate 3. In particular, the first adhesive layer 5 and the second adhesive layer 6 have a storage elastic modulus of 1 × 10 ⁵ N / m ² or more, and the third adhesive layer 7 has a storage elastic modulus of 3 ×. It is advantageous to form it so that it is 10 ⁴ N / m ² or less. In this case, each of the first adhesive layer and the second adhesive layer has a thickness of about 3 to 15 μm, preferably about 5 to 15 μm, which is good even if it is thinner than the 25 μm generally used conventionally. It is possible to effectively suppress the occurrence of cracks and wrinkles while maintaining a good adhesive force.

The upper and lower limits of the storage elastic modulus in each adhesive layer are not particularly limited, and the storage elastic modulus of the first adhesive layer 5 and the second adhesive layer 6 is, for example, about 10 ⁷ N / m ² . The storage elastic modulus of the third adhesive layer 7 may be, for example, about 10 ³ N / m ² .

  Control of the elastic modulus of the pressure-sensitive adhesive layer is achieved, for example, by adjusting the molecular weight of the base polymer in the pressure-sensitive adhesive, or by adjusting the content ratio of the crosslinkable functional group in the base polymer or the blending ratio of the cross-linking agent with respect to the base polymer. It can be carried out by an appropriate method according to a known method such as adjusting the degree of crosslinking or the molecular weight after crosslinking.

  The storage elastic modulus of the adhesive layer can be measured by heating the corresponding adhesive layer in the range from −70 ° C. to 200 ° C. at a rate of temperature increase of 4 ° C./min and a frequency of 1 Hz. The storage elastic modulus is a value measured when heated to 80 ° C. under the above conditions.

  The transparent protective layer, the retardation plate 2, the optical compensator 3, and the adhesive layers that constitute the linearly polarizing plate 1 may include, for example, salicylic acid ester compounds, benzophenone compounds, and benzotriazole compounds as necessary. Further, ultraviolet absorbing ability may be imparted by a method of blending an ultraviolet absorber such as a cyanoacrylate compound or a nickel complex salt compound.

  The elliptically polarizing plate according to the present invention is bonded to the linearly polarizing plate 1, the retardation plate 2 and the optical compensation plate 3 in advance for the purpose of preventing quality variation and improving the assembly efficiency of the liquid crystal display device. At the same time, a third adhesive layer is previously provided outside the optical compensation layer 3 so that it can be attached to the liquid crystal cell via the third adhesive layer. Therefore, it is preferably used for forming a liquid crystal display device. When the linearly polarizing plate 1, the phase difference plate 2 and the optical compensation plate 3 are laminated, their optical axes can be set at an appropriate arrangement angle in accordance with a target phase difference characteristic.

  In the liquid crystal display device of the present invention, the elliptically polarizing plate 10 described so far is attached to at least one surface of a liquid crystal cell on the third adhesive layer 7 side. The liquid crystal display device can be formed according to a conventional method. That is, a liquid crystal display device is generally formed by laminating a liquid crystal cell, a linear polarizing plate, and an optical compensator, incorporating components such as an illumination system as necessary, and further incorporating a drive circuit. The liquid crystal display device can be assembled according to a conventional method except that the elliptically polarizing plate 10 according to the present invention is attached to at least one surface of the liquid crystal cell.

  For example, an appropriate liquid crystal display device such as a liquid crystal display device in which a linear polarizing plate is disposed on one or both surfaces of a liquid crystal cell, or a backlight or a reflector used in an illumination system can be formed. Here, the elliptically polarizing plate 10 according to the present invention can be disposed on one side or both sides of the liquid crystal cell. Moreover, if the elliptically polarizing plate 10 of this invention is used, since an optical compensation board can be arrange | positioned between a linearly-polarizing plate and a liquid crystal cell, it is excellent in the compensation effect. In view of the compensation effect, it is particularly preferable to arrange the elliptically polarizing plate 10 of the present invention at least on the light source side of the liquid crystal cell. The elliptically polarizing plate 10 shown in FIG. 1 is attached to the liquid crystal cell with the third adhesive layer 7 after the separator 20 is peeled off.

  EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated further more concretely, this invention is not limited by these examples.

[Example 1]
A triacetyl cellulose film having a thickness of 40 μm is bonded to both surfaces of a polarizing film having a thickness of 30 μm in which iodine is adsorbed and oriented to polyvinyl alcohol via a polyvinyl alcohol-based adhesive layer. A linearly polarizing plate with a pressure-sensitive adhesive in which a first acrylic pressure-sensitive adhesive layer having a thickness of 25 μm was provided on the outside of the film was prepared. Further, it is made of a stretched film of norbornene-based resin and has a thickness of 25 μm on one side of a retardation plate [Sumikalite SES440270: trade name] sold by Sumitomo Chemical Co., Ltd., having an in-plane retardation value of 270 nm. Then, a second acrylic adhesive layer having a storage elastic modulus of 1 × 10 ⁵ N / m ² was provided to obtain a retardation plate with an adhesive. The side of the retardation plate with the pressure-sensitive adhesive on which the pressure-sensitive adhesive layer is not formed is bonded to the first pressure-sensitive adhesive layer of the linear polarizing plate with the pressure-sensitive adhesive, and the linearly polarizing plate / first pressure-sensitive adhesive layer / retardation plate / It was set as the structure of the 2nd adhesion layer.

Separately, an optical compensator in which a rod-like nematic liquid crystal is fixed on a triacetyl cellulose film in an obliquely oriented state while changing the tilt in the film thickness direction [“NH film” sold by Shin Nippon Oil Co., Ltd.] : Product name] was prepared. A third acrylic adhesive layer having a thickness of 25 μm and a storage elastic modulus of 3 × 10 ⁴ N / m ² provided on the separator is attached to the liquid crystal alignment layer side of the optical compensator, The triacetyl cellulose film as the substrate is peeled from the compensation plate, and then the exposed surface of the liquid crystal alignment layer (optical compensation plate) is placed on the linear polarizing plate / first adhesive layer / retardation plate / second adhesive. It stuck on the 2nd adhesion layer of the laminated product which consists of layers. Thus, an elliptically polarizing plate was produced. At this time, the stretching direction (slow axis) of the retardation plate is 0 degree, the stretching direction (absorption axis) of the linear polarizing plate is 70 degrees, the flow direction of the “NH film” (the length of the film supplied in roll form) (Direction) was set to 65 degrees.

[Comparative Example 1]
An elliptically polarizing plate is produced in the same manner as in Example 1 except that both the second acrylic adhesive layer and the third acrylic adhesive layer have a storage elastic modulus of 3 × 10 ⁴ N / m ^2. did.

[Comparative Example 2]
An elliptically polarizing plate was prepared in the same manner as in Example 1 except that both the second acrylic adhesive layer and the third acrylic adhesive layer had a storage elastic modulus of 1 × 10 ⁵ N / m ^2. did.

[Evaluation Test 1]
A sample of 45 mm × 40 mm size was cut out from the elliptically polarizing plate obtained in Example 1 and Comparative Examples 1 and 2 so that one side was at an angle of 45 degrees with respect to the absorption axis of the linearly polarizing plate constituting it. It adhere | attached on the single side | surface of the glass plate through the 3rd adhesion layer. At this time, glass pieces prepared in advance (with a diameter of 10 μm to 300 μmφ) were appropriately arranged on the glass surface so that glass foreign matters were sandwiched between the samples. For this sample, use a thermal shock tester “TSA-301L-W” (model name) manufactured by Tabai Espec Co., Ltd., hold at −40 ° C. for 0.5 hour, and then raise the temperature to 85 ° C. The thermal shock test was repeated for a maximum of 200 cycles, with holding for .5 hours as one cycle. The sample at the time of a predetermined cycle was observed, and the presence or absence of cracks in the liquid crystal alignment layer (optical compensation plate) was examined. The results are shown in Table 1.

  From Table 1, as in Example 1, the second adhesive layer interposed between the retardation plate and the optical compensation plate made of the liquid crystal layer is positioned outside the optical compensation plate made of the liquid crystal layer on the glass. It can be seen that the formation of cracks after the thermal shock test is suppressed even when foreign matter is present on the glass, by constituting it with a material having a larger storage elastic modulus than the third adhesive layer to be adhered.

[Example 2]
A triacetyl cellulose film having a thickness of 40 μm is bonded to one side of a polarizing film having a thickness of 30 μm in which iodine is adsorbed and oriented to polyvinyl alcohol via a polyvinyl alcohol-based adhesive layer, and the other side of the polarizing film has a thickness. A first acrylic pressure-sensitive adhesive layer having a storage modulus of ⁵ × m and a storage elastic modulus of 1 × 10 ⁵ N / m ² was provided to obtain a linearly polarizing plate with an adhesive. Further, the same in-plane retardation value as used in Example 1 has a thickness of 5 μm and a storage elastic modulus of 1 × 10 ⁵ N / m ² on one surface of a retardation plate “Sumikalite SES440270” with a 270 nm retardation value. The 2nd acrylic adhesive layer was provided and it was set as the phase difference plate with an adhesive. The side of the retardation plate with the pressure-sensitive adhesive on which the pressure-sensitive adhesive layer is not formed is bonded to the first pressure-sensitive adhesive layer of the linear polarizing plate with the pressure-sensitive adhesive, and the linearly polarizing plate / first pressure-sensitive adhesive layer / retardation plate / It was set as the structure of the 2nd adhesion layer.

Separately, an optical compensator in which a rod-like nematic liquid crystal is fixed on a triacetyl cellulose film in an obliquely oriented state while changing the tilt in the film thickness direction [“NH film” sold by Shin Nippon Oil Co., Ltd.] : Product name, but according to manufacturer information, the type is different from that used in Example 1.]. A third acrylic adhesive layer having a thickness of 25 μm and a storage elastic modulus of 3 × 10 ⁴ N / m ² provided on the separator is attached to the liquid crystal alignment layer side of the optical compensator, The triacetyl cellulose film as the substrate is peeled from the compensation plate, and then the exposed surface of the liquid crystal alignment layer (optical compensation plate) is placed on the linear polarizing plate / first adhesive layer / retardation plate / second adhesive. It stuck on the 2nd adhesion layer of the laminated product which consists of layers. Thus, an elliptically polarizing plate was produced. At this time, the absorption axis direction of the linear polarizing plate is 0 degree, the stretching direction (slow axis) of the retardation film is 135 degrees, and the flow direction of the “NH film” (longitudinal direction of the film supplied in a roll shape) is It arrange | positioned so that it might become 45 degree | times.

[Comparative Example 3]
The first acrylic adhesive layer has a thickness of 15 μm and a storage elastic modulus of 1 × 10 ⁵ N / m ² , and the second acrylic adhesive layer has a thickness of 15 μm and a storage elastic modulus of 3 × An elliptically polarizing plate was produced in the same manner as in Example 2 except that 10 ⁴ N / m ² was used.

[Evaluation Test 2]
A sample of 43.4 mm × 56.4 mm size was cut out from the elliptically polarizing plate obtained in Example 2 so that the long side was at an angle of 0 degree with respect to the absorption axis of the linearly polarizing plate constituting it. It adhere | attached on the single side | surface of the glass plate through the three adhesion layers. Further, from the elliptically polarizing plate obtained in Comparative Example 3, a sample having a size of 50.2 mm × 37.9 mm was cut out so that the long side was at an angle of 0 degree with respect to the absorption axis of the linearly polarizing plate. It adhere | attached on the single side | surface of the glass plate through the adhesion layer. About these samples, the thermometer “Perfect Oven PH (H) -201” manufactured by Tabai Espec Co., Ltd.
(Model name) was used, and a heat resistance test was performed for holding at 85 ° C. for a maximum of 2,000 hours. A sample at a predetermined time was observed to examine whether or not wrinkles occurred in the short part of the liquid crystal alignment layer (optical compensation plate). The results are shown in Table 2.

  From Table 2, as in Example 2, the first adhesive layer interposed between the linearly polarizing plate and the retardation plate and the second adhesive layer interposed between the retardation plate and the optical compensator composed of the liquid crystal layer. By forming the adhesive layer with a larger storage elastic modulus than the third adhesive layer, which is positioned outside the optical compensation plate made of a liquid crystal layer and adhered to the glass, generation of wrinkles after the heat resistance test occurs. It turns out that it is suppressed. Usually, wrinkles due to heat shrinkage are more likely to occur as the size increases. Although the sample size used in Example 2 and Comparative Example 3 is different, no wrinkle is generated in Example 2 having a larger size, and the configuration of Example 2 can effectively work to suppress wrinkles. Recognize.

It is a cross-sectional schematic diagram which shows the example of an elliptically polarizing plate.

Explanation of symbols

1 ... Linear polarizing plate,
2 ... retardation plate,
3 …… Optical compensation plate,
5 …… First adhesive layer,
6 …… Second adhesive layer,
7: Third adhesive layer,
10 …… Ellipse polarizing plate,
20 …… Separator.

Claims (3)

A linear polarizing plate, a first adhesive layer, a retardation plate, a second adhesive layer, an optical compensation plate composed of a liquid crystal layer, and a third adhesive layer are laminated in this order, and the first adhesive layer and the second adhesive layer Both of the adhesive layers have a storage elastic modulus of 1 × 10 ⁵ N / m ² or more, and the third adhesive layer has a storage elastic modulus of 3 × 10 ⁴ N / m ² or less. An elliptically polarizing plate.   The elliptically polarizing plate according to claim 1, wherein the optical compensation plate does not have a support and is substantially composed only of an alignment layer of liquid crystal. A liquid crystal display device, wherein the elliptically polarizing plate according to claim 1 or 2 is attached to at least one surface of the liquid crystal cell on the third adhesive layer side.

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