JP6274446B2 - Long optical film laminate, roll of long optical film laminate, and IPS liquid crystal display device - Google Patents

Description

  The present invention relates to an optical film laminate in which a polarizing plate and a retardation film, which are suitable for an IPS liquid crystal panel operating in an in-plane switching (IPS) mode, have a wide viewing angle, a high degree of polarization, and good humidifying optical durability are laminated. . The present invention also relates to a liquid crystal display device having a wide viewing angle and good heat warping (curl) in an IPS liquid crystal display device using the optical film laminate.

  In the IPS liquid crystal display device operating in the IPS mode, since the liquid crystal molecules have a homogeneous alignment substantially parallel to the substrate surface in the non-driven state, the light passes through the liquid crystal layer with almost no change in its polarization plane. As a result, by disposing polarizing plates above and below the substrate, almost complete black display is possible in a non-driven state. In the IPS mode, almost complete black display is possible in the panel normal direction, but when observing the panel from the direction shifted from the normal direction, the direction shifted from the optical axis direction of the polarizing plate arranged above and below the liquid crystal cell However, there is a problem that the viewing angle is narrowed as a result of light leakage that is unavoidable due to the characteristics of the polarizing plate.

  In order to solve such a problem, for example, in Japanese Patent Laid-Open No. 3,687,854 (Patent Document 1), lamination is performed so that the absorption axis of the polarizing plate and the slow axis of the retardation film are orthogonal or parallel to each other. Parameters such as the refractive index, retardation and thickness of the optical film are set to values suitable for the IPS liquid crystal display panel. In one embodiment, a polarizing plate in which a transparent protective film having a thickness of 80 μm is laminated on both surfaces of a polarizer having a thickness of 20 μm using an adhesive, a retardation film having a thickness of 45 μm, and the like are used.

  Japanese Patent No. 4,938,632 (Patent Document 2) describes that a polarizer having a thickness of 10 μm to 50 μm is used in an IPS liquid crystal display device. Further, in Japanese Patent No. 4,804,588 (Patent Document 3), a retardation film is bonded to the viewing side surface of the IPS liquid crystal display panel via an adhesive layer, and the thickness of the retardation film is 10 μm or less. Are described as being bonded. Further, Japanese Patent No. 4,757,347 (Patent Document 4) describes an optical film of 20 μm or less as a retardation film.

  IPS liquid crystal display panels using such optical films such as polarizers and retardation films are not only used for relatively large screens such as liquid crystal televisions and liquid crystal displays, but are also recently portable for smartphones, tablet PCs, etc. It is also applied to the screens of small electronic devices. In recent years, IPS liquid crystal display panels (glass) have been manufactured thinly as the portable electronic devices become thinner.

Japanese Patent No. 3,687,854 Japanese Patent No. 4,938,632 Japanese Patent No. 4,804,588 Japanese Patent No. 4,757,347 Japanese Patent No. 4,751,481 Japanese Patent No. 4,751,486 Japanese Patent No. 5,244,848 Japanese Patent No. 4,853,920

  Due to the thinning of the IPS liquid crystal display panel, warping occurs in a configuration in which an optical film such as a polarizer or a retardation film is bonded to the IPS liquid crystal display panel. Such warpage adversely affects the functions of the polarizer, retardation film, and the like, and can occur when the IPS liquid crystal display panel is viewed from an oblique direction (for example, an angle of 45 degrees) with respect to the absorption axis of the polarizer. There is a problem that the function that the polarizer and the retardation film should originally perform, such as the reduction in contrast and the phenomenon (color shift) that varies depending on the viewing angle of the display color, does not work effectively.

  Therefore, the present invention reduces the thickness of the polarizer that is easily stretchable and the retardation film between the polarizer and the IPS liquid crystal display panel, thereby further reducing the IPS liquid crystal display to the polarizer. The object is to approach the panel and thereby prevent warping of the IPS liquid crystal display panel. And in addition to achieving the said objective, this invention has the performance of a wide viewing angle and a high degree of polarization even if it makes a polarizer and retardation film thin, and long optical with favorable humidification optical durability A film laminate, a roll of a long optical film laminate in which the long optical film laminate is wound into a roll, and an IPS liquid crystal display device are proposed.

As one embodiment of the long optical film laminate for the IPS liquid crystal display device according to the present invention, the long optical film laminate is a polyvinyl alcohol-based resin layer stretched in the longitudinal direction so as to have a thickness of 12 μm or less. And an elongated web-like PVA-iodine polarizer comprising iodine adsorbed in the form of a PVA polyiodine ion complex to the PVA molecular chain oriented in the stretching direction of the polyvinyl alcohol resin layer,
A long web-like retardation film directly bonded to one surface of the polarizer via a first adhesive layer;
A first pressure-sensitive adhesive layer disposed on the surface of the retardation film opposite to the polarizer;
A long web-like release film bonded to the surface of the first pressure-sensitive adhesive layer opposite to the retardation film;
A protective layer bonded to the surface of the polarizer opposite to the retardation film via a second adhesive layer,
The polarizer has a concentration of iodine of 3% by weight or more with respect to the polyvinyl alcohol resin, an orientation of PVA molecules of 0.38 or more, and a polarization degree of 99.8% or more.
The retardation film has a x-axis direction in which the in-plane refractive index is maximum, a y-axis direction in the film plane perpendicular to the x-axis, and a z-axis film thickness direction. The refractive index nx, ny, nz in the y-axis and z-axis directions has a refractive index distribution in which nx>nz> ny, and the thickness d is 20 μm or less, and the in-plane refractive index difference Δnxy Is 5.5 × 10 ⁻³ or more, Re defined as Re = (nx−ny) × d is 100 to 300 nm, and Nz defined as Nz = (nx−nz) / (nx−ny) is 0.00. 3 to 0.8, the photoelastic coefficient is 5 × 10 ⁻¹¹ or more, and has a slow axis in the width direction perpendicular to the longitudinal direction,
Each of the first and second adhesive layers has a thickness of 2 μm or less and an elastic modulus in the range of 1 × 10 ⁵ to 3 × 10 ⁹ Pa,
When the thickness of the protective layer is 10 to 50 μm and the polarizer thickness is greater than 10 μm, the moisture permeability is 1500 g / m ² or less, and when the polarizer thickness is 10 μm or less, the moisture permeability is 200 g / m ² or less. It is characterized by being.

  As a preferred embodiment of the long optical film laminate for the IPS liquid crystal display device according to the present invention, the surface on the second adhesive layer side of the polarizer and the surface on the first adhesive layer side of the release film The distance between and is 50 μm or less.

  As a preferred embodiment of the long optical film laminate for the IPS liquid crystal display device according to the present invention, the long optical film laminate is wound in a roll shape.

As one embodiment of the IPS liquid crystal display device according to the present invention, an IPS liquid crystal display device includes an IPS liquid crystal display panel,
A viewing-side optical film laminate including at least a polarizer and a retardation film, disposed on the viewing side of the IPS liquid crystal display panel;
A backlight side optical film laminate including at least a polarizer and a brightness enhancement film, disposed on the backlight side of the IPS liquid crystal display panel,
The polarizer contained in the viewing-side optical film laminate has a polyvinyl alcohol resin layer stretched in a uniaxial direction so that the thickness is 12 μm or less, and PVA oriented in the stretch direction of the polyvinyl alcohol resin layer. A long web-like PVA iodine-based polarizer containing iodine adsorbed on the molecular chain in the form of a PVA polyiodine ion complex;
The polarizer contained in the viewing-side optical film laminate has an iodine concentration of 3% by weight or more, a PVA molecule orientation of 0.38 or more, and a polarization degree of 99.8% or more.
The retardation film has a x-axis direction in which the in-plane refractive index is maximum, a y-axis direction in the film plane perpendicular to the x-axis, and a z-axis film thickness direction. The refractive index nx, ny, nz in the y-axis and z-axis directions has a refractive index distribution in which nx>nz> ny, and the thickness d is 20 μm or less, and the in-plane refractive index difference Δnxy Is 5.5 × 10 ⁻³ or more, Re defined as Re = (nx−ny) × d is 100 to 300 nm, and Nz defined as Nz = (nx−nz) / (nx−ny) is 0.00. 3 to 0.8, the photoelastic modulus is 5 × 10 ⁻¹¹ or more, the slow axis is substantially perpendicular to the absorption axis of the polarizer, the thickness is 2 μm or less, and the elastic modulus is 1 × 10 ^5. To 3 × 10 ⁹ Pa directly through the adhesive layer of the viewing-side optical film laminate Bonded to the polarizer,
The retardation film is bonded to the viewing-side surface of the IPS liquid crystal display panel via an adhesive layer, and the polarizing film is formed on the viewing-side surface of the IPS liquid crystal display panel from the viewing-side surface of the IPS liquid crystal display panel. The distance to the second adhesive layer side surface of the child is 50 μm or less,
The polarizer included in the backlight-side optical film laminate was oriented in the stretching direction of the polyvinyl alcohol-based resin layer stretched in a uniaxial direction so that the thickness was 12 μm or less, and the polyvinyl alcohol-based resin layer. A PVA-iodine-based polarizer comprising iodine adsorbed on the PVA molecular chain in the form of a PVA polyiodine ion complex,
The polarizer included in the backlight-side optical film laminate has an iodine concentration of 3% by weight or more, a PVA molecule orientation of 0.38 or more, and a polarization degree of 99.8% or more. The surface is bonded to the protective layer through a third adhesive layer having a thickness of 2 μm or less and an elastic modulus in the range of 1 × 10 ⁵ to 3 × 10 ⁹ Pa,
The protective layer is bonded to the backlight side surface of the IPS liquid crystal display panel via a second pressure-sensitive adhesive layer, and on the backlight side of the IPS liquid crystal display panel, the backlight side of the IPS liquid crystal display panel The distance from the surface to the backlight side surface of the polarizer is 50 μm or less,
The difference between the distance from the viewing side surface of the IPS liquid crystal display panel to the protective layer side surface of the polarizer and the distance from the backlight side surface of the IPS liquid crystal display panel to the backlight side surface of the polarizer is 10 μm or less. It is characterized by being.

  As a preferred embodiment of the IPS liquid crystal display device according to the present invention, the polarizer contained in the viewing-side optical film laminate has a protective film on the surface opposite to the retardation film via an adhesive layer. Is characterized by being joined. Further, the polarizer included in the backlight-side optical film laminate is provided with a protective layer on both sides or one side.

As a preferred embodiment of the IPS liquid crystal display device according to the present invention, the adhesive layer has a thickness of 2 μm or less and an elastic modulus of 1 × 10 ⁵ to 3 × 10 ⁹ .

  As another embodiment of the IPS liquid crystal display device according to the present invention, the same configuration as the viewing-side optical film laminate is provided on the backlight side as the backlight-side optical film laminate, and the other configurations described above are the embodiments described above. The same shall apply.

  The present invention provides a polarizer with a long optical film laminate for an IPS liquid crystal display device in which the thickness of the polarizer is reduced and the thickness of the retardation film between the polarizer and the IPS liquid crystal display panel is also reduced. Can be brought close to the IPS liquid crystal display panel, and warping of the IPS liquid crystal display panel to which the optical film laminate is attached can be prevented.

  Moreover, the long optical film laminate according to the present invention, the roll of the long optical film laminate in which the long optical film laminate is wound in a roll shape, or the IPS liquid crystal display device includes a polarizer and a retardation film. In addition to reducing the thickness, parameters such as the orientation of the PVA molecules in the polarizer, the degree of polarization, the refractive index of the retardation film, the photoelastic modulus, and the moisture permeability of the protective film are based on the comparison results of a plurality of examples. By setting the value suitable for the IPS liquid crystal display device, even when the polarizer and the retardation film were thinned, the performance of a wide viewing angle and a high degree of polarization was obtained, and the humidifying optical durability was good.

It is sectional drawing which shows the structure of the elongate optical film laminated body for IPS liquid crystal display devices which concerns on one Embodiment of this invention. It is sectional drawing which shows the structure of the IPS liquid crystal display device provided with the optical film laminated body which concerns on one Embodiment of this invention in the visual recognition side. It is sectional drawing which shows the structure of the IPS liquid crystal display device provided with the optical film laminated body which concerns on another embodiment of this invention in the visual recognition side. It is sectional drawing which shows the structure of the IPS liquid crystal display device provided with the optical film laminated body which concerns on one Embodiment of this invention in the backlight side. It is sectional drawing which shows the structure of the IPS liquid crystal display device provided with the optical film laminated body which concerns on another embodiment of this invention in the backlight side.

  FIG. 1 shows a configuration of a long optical film laminate for an IPS liquid crystal display device according to an embodiment of the present invention. In the optical film laminate 100, an adhesive layer 102, a polarizer 103, an adhesive layer 104, and a protective film 105 are laminated on one surface of the retardation film 101 (upper surface in FIG. 1). Is provided with an adhesive layer 106 and a release film 107 on the other surface (the lower surface in FIG. 1). The retardation film 101 and the polarizer 103 are directly bonded together via the adhesive layer 102. When the optical film laminate 100 is bonded to an object such as an IPS liquid crystal panel by the pressure-sensitive adhesive layer 106, the release film 107 is peeled off from the pressure-sensitive adhesive layer 106.

(Retardation film)
A retardation film can be manufactured based on the manufacturing method described in patent 4,757,347 (patent document 4), for example. The method for producing the retardation film includes a birefringence including a non-liquid crystalline material having a birefringence (Δnxz) in the thickness direction represented by Δnxz = nx′−nz ′ of 0.0007 or more on a shrinkable film. The coating film is contracted so that the refractive index distribution of the coating film becomes nx>nz> ny by the coating film forming process in which the layer forming material is directly applied to form the coating film and the shrinkage of the shrinkable film. And a birefringent layer forming step of forming a birefringent layer. However, each variable is as follows.
nx ′: refractive index nz ′ in the direction (slow axis direction) in which the refractive index is maximum in the plane of the layer when the non-liquid crystalline material is used as a solidified layer: the direction of nx ′ and the plane of the solidified layer The refractive index nx in the thickness direction of the solidified layer orthogonal to each direction of the direction (fast axis direction) orthogonal to the direction of nx ′ in the direction in which the refractive index is maximum in the plane of the birefringent layer Refractive index ny in the slow axis direction: Refractive index nz in the direction (fast axis direction) orthogonal to the nx direction in the plane of the birefringent layer: orthogonal to the nx and ny directions Refractive index in the thickness direction of the birefringent layer

In accordance with the above definition, when the film in-plane refractive index is the maximum in the x-axis, the in-plane direction perpendicular to the x-axis is the y-axis, and the film thickness direction is the z-axis, the book shown in FIG. Retardation film 101 in one embodiment of the invention takes into account the results of the following examples (see Table 1), for example, the refractive indexes nx, ny, and nz in the x-axis, y-axis, and z-axis directions are nx>. The film is formed as a single-layer film having a refractive index distribution satisfying nz> ny and having a thickness d of 20 μm or less, and the in-plane refractive index difference Δnxy is 5.5 × 10 ⁻³ or more, Re = (nx−ny) Re defined as xd is 100 to 300 nm, preferably 130 to 300 nm, particularly preferably 250 to 290 nm. Nz defined as Nz = (nx−nz) / (nx−ny) is 0.3 to 0.8, more preferably 0.35 to 0.75, and particularly preferably 0.4 to 0.6. . The photoelastic coefficient is 5 × 10 ⁻¹¹ or more, more preferably 1 × 10 ⁻¹⁰ or more, and it can be configured to have a slow axis in the width direction perpendicular to the longitudinal direction.

(Polarizer)
In general, a polarizer is formed by uniaxially or biaxially stretching a polyvinyl alcohol (PVA) resin film impregnated and adsorbed with a dichroic substance by a dyeing process and orienting the impregnated dichroic substance. Created. In recent years, it is common to use iodine as a dichroic substance. In the dyeing process, the PVA resin film is immersed in an iodine aqueous solution. However, since only iodine molecules (I2) do not dissolve in water, iodine is dissolved in water together with potassium iodide (KI). An aqueous potassium iodide solution is prepared. In the iodine / potassium iodide aqueous solution, in addition to potassium ions (K +) and iodine ions (I−), polyiodine ions (I3− and I5−) in which iodine ions and iodine molecules are combined exist. In the dyeing step, iodine ions and polyiodine ions penetrate into the PVA resin film and are adsorbed by the PVA resin molecules. In the subsequent stretching step, when the PVA resin film is stretched and the molecules are oriented, the polyiodine ions are also oriented in the stretching direction. Since oriented polyiodine ions have different transmittances of incident light depending on the angle of the polarization direction of incident light with respect to the orientation direction of polyiodine ions, the dyed and stretched PVA resin functions as a polarizer.

  Thus, the polarizer includes at least a PVA-based resin and polyiodine ions. The polyiodine ion exists in a state where a PVA-iodine complex (PVA • I 3− or PVA • I 5−) is formed in the polarizer by interaction with the PVA resin molecule. By forming this complex state, absorption dichroism is exhibited in the wavelength range of visible light. Iodine ion (I-) has an absorption peak near 230 nm. Further, triiodide ion (PVA · I 3−) in a complex state with PVA has an absorption peak near 470 nm. An absorption peak of pentaiodide ion (PVA · I5−) in a complex state with PVA exists in the vicinity of 600 nm. Depending on the mode of the PVA-iodine complex, the wavelength of light to be absorbed changes, so that the absorption peak of polyiodine ions is wide. The PVA-iodine complex absorbs visible light. On the other hand, iodine ions do not absorb visible light because they have a peak near 230 nm. Therefore, the polyiodine ion complexed with PVA affects the performance of the polarizer relating to a display device such as a liquid crystal display device of the polarizer. In consideration of the results of the following examples (see Table 1), the polarizer 103 in one embodiment of the present invention shown in FIG. 1 has, for example, a concentration of iodine of 3% by weight or more relative to the polyvinyl alcohol-based resin. The orientation can be 0.38 or more and the degree of polarization can be 99.8% or more.

  In one embodiment of the present invention shown in FIG. 1, the polarizer 103 has a thickness of 12 μm or less, preferably 5 μm or less. For example, a polarizer having a thickness of 12 μm can be produced according to the production method described above using polyvinyl alcohol having a thickness of the original film of 30 μm. Thus, by making the polarizer thin, the stretching force generated in the polarizer due to changes in the surrounding environment can be reduced. When the polarizer is relatively thick, the stretching force generated in the polarizer increases, so it is necessary to attach a protective layer or retardation layer with a thickness sufficient to suppress the stretching of the polarizer. become. On the other hand, the thickness of the protective layer or retardation layer bonded to the polarizer can be reduced by reducing the stretching force generated in the polarizer by thinning the polarizer, and the thickness of the entire optical laminate can be reduced. Can be thinned. In addition, since the thickness of the polarizer is thin and the expansion and contraction force generated in the polarizer is reduced due to the change in the surrounding environment, the stress generated between the polarizer and the member to be bonded to the member is reduced, which occurs in the bonded member. The optical distortion is also suppressed.

  The polarizer 103 preferably exhibits absorption dichroism at any wavelength between 380 nm and 780 nm. The single transmittance of the polarizer is preferably 40.0% or more, more preferably 40.5% or more, further preferably 41.0% or more, and particularly preferably 41.5% or more. The polarization degree of the polarizer is preferably 99.8% or more, more preferably 99.9% or more, and further preferably 99.95% or more. Thus, it is not easy to manufacture a thin polarizer that exhibits high polarization performance. However, by adopting any of the methods described in Patent Documents 5 to 7 described above by the present applicant, a thin polarizer having desired characteristics can be manufactured.

(Protective film)
Any appropriate resin film can be adopted as the protective film. Examples of the material for forming a protective film suitable for use in the present invention include cycloolefin resins such as norbornene resins, olefin resins such as polyethylene and polypropylene, polyester resins, (meth) acrylic resins, and cellulose. Examples include ester resins. The “(meth) acrylic resin” means at least one of an acrylic resin and a methacrylic resin.

  In one embodiment of the present invention shown in FIG. 1, the thickness of the protective film 105 is 10 μm to 50 μm, preferably 15 μm to 45 μm. When the protective film is disposed on the viewing side of the liquid crystal display device, a surface treatment layer such as an antiglare layer or an antireflection layer and a hard coat treatment for preventing scratches can be appropriately provided. In addition, although not particularly limited, in-cell capacitive touch panels include a transparent conductive film having an electromagnetic shielding and antistatic function in order to prevent interference with display operations due to low-frequency noise near the display. It is necessary to apply to the protective film. Further, when the protective film itself is a λ / 4 plate, it is a measure for reducing visibility in polarized sunglasses.

When the thickness of the polarizer is 10 μm or less, the transmission humidity of the protective film 105 is 200 g / m ² or less, preferably 170 g / m ² or less, more preferably 130 g / m ² or less, and particularly preferably 90 g / m ² or less. is there. The polarizer has a problem that the moisture resistance decreases as the thickness decreases. By reducing the moisture permeability of the protective layer as described above, it is possible to suppress the deterioration of the polarizer due to the humidity and to reduce the thickness of the polarizer. When the thickness of the polarizer is larger than 10 μm, the deterioration of the polarizer due to the humidity can be suppressed if the moisture permeability is 1500 g / m ² or less. By reducing the thickness of the polarizer, the thickness of the protective layer or retardation layer to be bonded to the polarizer can be reduced as described above, and as a result, the thickness of the entire optical laminate can be reduced.

  FIG. 2 shows a configuration of an IPS liquid crystal display device including an optical film laminate according to an embodiment of the invention on the viewing side. The IPS liquid crystal display device 200 includes an adhesive layer 202, an undercoat layer 203, a retardation film 204, and an undercoat layer 205 on one surface (an upper surface in FIG. 2) of an in-cell touch panel type liquid crystal cell (T / P) 201. The adhesive layer 206, the polarizer 207, the adhesive layer 208, the protective film 209, the surface treatment (conductive) layer 210, the interlayer filling layer 211, and the glass 212 are laminated. On the other hand, the pressure-sensitive adhesive layer 213, the protective film 214, the adhesive layer 215, the polarizer 216, the adhesive layer 217, and the protective film 218 are formed on the other surface (the lower surface in FIG. 2) of the liquid crystal cell (T / P) 201. The adhesive layer 219 and the brightness enhancement film 220 are laminated. The IPS liquid crystal display device 200 further includes a diffusion plate 221 and a backlight 222 joined to the diffusion plate 221 at a distance from the brightness enhancement film 220. The backlight 222 is bonded to the surface of the diffusion plate 221 opposite to the brightness enhancement film 220.

  The pressure-sensitive adhesive layer 202, the retardation film 204, the adhesive layer 206, the polarizer 207, the adhesive layer 208, and the protective film 209 are the pressure-sensitive adhesive layer 106, the phase difference film 101, and the optical film laminate 100 shown in FIG. 1. This corresponds to the adhesive layer 102, the polarizer 103, the adhesive layer 104, and the protective film 105. The undercoat layers 203 and 205 can be omitted if the retardation film 204, the adhesive layer 202, and the adhesive layer 206 are strongly bonded.

  The liquid crystal cell (T / P) 201 is an IPS liquid crystal cell, and has a homogeneous alignment in which liquid crystal molecules are uniformly aligned in one in-plane direction when no electric field is applied. In the IPS liquid crystal display device including the IPS liquid crystal cell having this configuration, a pair of polarizers are arranged on both sides of the liquid crystal cell with their absorption axes orthogonal to each other.

  When no electric field is applied, the polarizer is arranged with respect to the liquid crystal cell so that the absorption axis of one polarizer is parallel to the alignment direction of the liquid crystal molecules. Normally, this state where no electric field is applied corresponds to “black display”. By applying an electric field to the liquid crystal cell and rotating the liquid crystal molecules in the horizontal direction in the plane, the phase difference is developed and the light passing through the one polarizer can pass through the other polarizer, "White state" is realized. The “white state” is realized in a state where the liquid crystal molecules have the maximum transmittance toward the intermediate angle between the crossing angles of the absorption axes of the pair of polarizers, that is, in the direction of 45 °. Actually, it is difficult to rotate the liquid crystal molecules to the ideal orientation of 45 °, and an orientation angle substantially close to 45 ° is regarded as a “white state”. The IPS liquid crystal display device in which the polarizer on the backlight source side is arranged in parallel with the alignment direction of the liquid crystal molecules in the state where no electric field is applied is called “O mode”. An IPS liquid crystal display device arranged in parallel with the alignment direction of liquid crystal molecules in an applied state is called an “E mode”.

(Brightness enhancement film)
The brightness enhancement film reflects the linearly polarized light with a predetermined polarization axis or circularly polarized light in a predetermined direction and transmits other light when natural light is incident on the backlight of a liquid crystal display device or the like by reflection from the back side. It is. The polarizing plate on which the brightness enhancement film is laminated allows light from a light source such as a backlight to enter to obtain transmitted light in a predetermined polarization state, and reflects the light other than the predetermined polarization state without transmitting it. By reversing the light reflected by the brightness enhancement film surface through a reflective layer or the like provided behind the brightness enhancement film and re-entering the brightness enhancement film, part or all of the light is transmitted as light having a predetermined polarization state. Thus, the luminance can be improved by increasing the amount of light transmitted through the brightness enhancement film and supplying the polarized light that is not easily absorbed by the polarizer to increase the amount of light that can be used for liquid crystal image display and the like.

  FIG. 3 shows a configuration of an IPS liquid crystal display device including an optical film laminate according to another embodiment of the present invention on the viewing side. Unlike the liquid crystal cell (T / P) 201 of the IPS liquid crystal display device 200 shown in FIG. 2, the IPS liquid crystal display device 300 employs a liquid crystal cell 301 that is not an in-cell touch panel type as a liquid crystal panel, and the surface of the interlayer filling layer 311 A touch panel 323 is provided on the surface opposite to the treatment layer 310. The other configuration of the IPS liquid crystal display device 300 is the same as that of the IPS liquid crystal display device 200 shown in FIG.

FIG. 4 shows a configuration of an IPS liquid crystal display device including the optical film laminate according to one embodiment of the present invention on the backlight side. Unlike the IPS liquid crystal display device 200 shown in FIG. 2, the IPS liquid crystal display device 400 includes a retardation film 412 on the backlight side.
The IPS liquid crystal display device 400 includes an adhesive layer 402, a coat layer or a protective layer 403, a polarizer 404, an adhesive on one surface (an upper surface in FIG. 4) of an in-cell touch panel type liquid crystal cell (T / P) 401. The agent layer 405, the protective film 206, the surface treatment (conductive) layer 407, the interlayer filling layer 408, and the glass 409 are laminated. On the other hand, the pressure-sensitive adhesive layer 410, the undercoat layer 411, the retardation film 412, the undercoat layer 413, the adhesive layer 414, and the polarizer 415 are formed on the other surface (the lower surface in FIG. 4) of the liquid crystal cell (T / P) 401. The adhesive layer 416, the protective film 417, the pressure-sensitive adhesive layer 418, and the brightness enhancement film 419 are laminated. The undercoat layers 411 and 413 can also be omitted if the retardation film 412 and the adhesive layer 410 and the adhesive layer 414 are strongly bonded. The IPS liquid crystal display device 400 further includes a diffusion plate 420 and a backlight 421 bonded to the diffusion plate 420 with a space from the brightness enhancement film 419. The backlight 421 is bonded to the surface of the diffusion plate 420 opposite to the brightness enhancement film 419.

  In general, a thin adhesive polarizing plate with a transparent protective film only on one side of the polarizer has poor durability and is prone to cracks in the stretching direction of the polarizer when placed in a harsh environment. The layer or protective layer 403 can be bonded to the polarizer 404 in order to improve crack resistance. The other configuration of the IPS liquid crystal display device 400 is the same as that of the IPS liquid crystal display device 200 shown in FIG.

  FIG. 5 shows a configuration of an IPS liquid crystal display device including an optical film laminate according to another embodiment of the present invention on the backlight side. Unlike the liquid crystal cell (T / P) 401 of the IPS liquid crystal display device 400 shown in FIG. 4, the IPS liquid crystal display device 500 employs a liquid crystal cell 501 that is not an in-cell touch panel type as the liquid crystal panel, and the surface of the interlayer filling layer 508 A touch panel 522 is provided on the surface opposite to the treatment layer 507. The other configuration of the IPS liquid crystal display device 500 is the same as that of the IPS liquid crystal display device 400 shown in FIG.

  The description about Examples 1 to 7 of the present invention will be described below. In addition, for comparative reference, description is also given for Comparative Examples 1 to 3. Table 1 summarizes the examples and comparative examples. The items in the upper upper column in Table 1 represent those stacked on the upper and lower surfaces of the liquid crystal cell. For example, the “protective layer”, “second adhesive layer”, “viewing-side polarizer”, “first adhesive layer”, “retardation film”, “ The “first pressure-sensitive adhesive layer”, “second pressure-sensitive adhesive layer”, “protective layer”, “third adhesive layer”, and “backlight-side polarizer” are each a part of the present invention shown in FIG. In the embodiment, “protective film 209”, “adhesive layer 208”, “polarizer 207”, “adhesive layer 206”, “retardation film 204”, “adhesive layer 202”, “adhesive layer 213”. , “Protective film 214”, “adhesive layer 215”, and “polarizer 216”.

(Production example of retardation film 1)
In a reaction vessel equipped with a stirrer, 2.70 kg of 2,2-bis (4-hydroxyphenyl) -4-methylpentane and 0.06 kg of tetrabutylammonium chloride were dissolved in 25 L of 1M sodium hydroxide solution. A solution prepared by dissolving 1.22 kg of terephthalic acid chloride and 0.81 kg of isophthalic acid chloride in 30 L of toluene was added to this solution while stirring, and the mixture was stirred at room temperature for 90 minutes. Thereafter, the polymerization solution was allowed to stand to separate the toluene solution containing the polymer, then washed with acetic acid water, washed with ion-exchanged water, and then poured into methanol to precipitate the polymer. The precipitated polymer was filtered and dried under reduced pressure to obtain 3.41 kg of white polymer (yield 92%).

  The obtained polymer was dissolved in toluene, applied onto biaxially stretched polypropylene, dried at 80 ° C. for 5 minutes, and then dried at 110 ° C. for 5 minutes to produce a laminated film having a coating film of 15 μm. While transporting the obtained laminated film using a simultaneous biaxial stretching machine, the film is stretched 1.2 times in the width direction at 145 ° C. and contracted to 0.75 times in MD to form a roll. A retardation film 1 was obtained. The obtained retardation film 1 had a thickness of 15.0 μm, Re = 275 nm, Rth = 138 nm, and Nz coefficient = 0.5.

(Production example of retardation film 2)
The polymer obtained above was dissolved in toluene, applied onto biaxially stretched polypropylene, dried at 80 ° C. for 5 minutes, and then dried at 110 ° C. for 5 minutes to produce a laminated film having a coating film of 15 μm. . While transporting the obtained laminated film using a simultaneous biaxial stretching machine, the film is stretched 1.25 times in the width direction at 145 ° C. and contracted to 0.80 times in MD to form a roll. A retardation film 2 was obtained. The obtained retardation film 2 had a thickness of 15.0 μm, Re = 275 nm, Rth = 206 nm, and Nz coefficient = 0.75.

(Production example of retardation film 3)
The polymer obtained above was dissolved in toluene, applied onto biaxially stretched polypropylene, dried at 80 ° C. for 5 minutes, and then dried at 110 ° C. for 5 minutes to produce a laminated film having a coating film of 15 μm. . While transporting the obtained laminated film using a simultaneous biaxial stretching machine, the film is stretched 1.15 times in the width direction at 145 ° C. and contracted to 0.7 times in MD to form a roll. Of retardation film 3 was obtained. The obtained birefringent film had a thickness of 15.0 μm, Re = 275 nm, Rth = 96 nm, and Nz coefficient = 0.35.

(Production example of retardation film 4)
The obtained polymer was dissolved in toluene, applied onto biaxially stretched polypropylene, dried at 80 ° C. for 5 minutes, and then dried at 110 ° C. for 5 minutes to produce a laminated film having a coating film of 20 μm. . While transporting the obtained laminated film using a simultaneous biaxial stretching machine, the film is stretched 1.18 times in the width direction at 145 ° C. and contracted to 0.78 times in MD to form a roll. A retardation film 4 was obtained. The obtained retardation film 4 had a thickness of 20.0 μm, Re = 275 nm, Rth = 138 nm, and Nz coefficient = 0.50.

(Production example of retardation film 5)
The obtained polymer was dissolved in toluene, applied onto biaxially stretched polypropylene, dried at 80 ° C. for 5 minutes, and then dried at 110 ° C. for 5 minutes to produce a laminated film having a coating film of 10 μm. . While transporting the obtained laminated film using a simultaneous biaxial stretching machine, the film is stretched 1.22 times in the width direction at 145 ° C. and contracted to 0.73 times in MD to form a roll. A retardation film 5 was obtained. The obtained retardation film 5 had a thickness of 10 μm, Re = 275 nm, Rth = 138 nm, and Nz coefficient = 0.50.

(Production example of polarizer)
An A-PET (amorphous-polyethylene terephthalate) film (trade name: Novaclear SH046 200 μm, manufactured by Mitsubishi Plastics, Inc.) was prepared as a base material, and the surface was subjected to corona treatment (58 W / m ² / min). On the other hand, 1 wt% of acetoacetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name: Gohsephimer Z200 (degree of polymerization 1200, degree of saponification 99.0% or more, degree of acetoacetyl modification 4.6%)) Prepared PVA (polymerization degree 4200, saponification degree 99.2%) was applied so that the film thickness after drying was 12 μm, dried in hot air at 60 ° C. for 10 minutes, A laminate in which a PVA resin layer was provided on the material was produced.

  Next, the laminate was first stretched 2.0 times in the MD direction at 130 ° C. in air to produce a stretched laminate. Next, a step of insolubilizing the PVA layer in which the PVA molecules contained in the stretched laminate were oriented was performed by immersing the stretched laminate in a boric acid insolubilized aqueous solution having a liquid temperature of 30 ° C. for 30 seconds. The boric acid aqueous solution for insolubilization in this step contains 3 parts by weight of boric acid content with respect to 100 parts by weight of water. A colored laminate was produced by dyeing the stretched laminate after the insolubilization step. In this colored laminate, iodine is adsorbed on the PVA layer contained in the stretched laminate by immersing the stretched laminate in a dyeing solution. The staining solution contains iodine and potassium iodide, the temperature of the staining solution is 30 ° C., water is the solvent, the iodine concentration is in the range of 0.08 to 0.25% by weight, and the potassium iodide concentration Was in the range of 0.56 to 1.75% by weight. The ratio of iodine to potassium iodide concentration was 1: 7. As dyeing conditions, the iodine concentration and the immersion time were set so that the single transmittance of the PVA resin layer constituting the polarizer was 40.9%.

  Next, the colored laminate was immersed in an aqueous boric acid solution for crosslinking at 30 ° C. for 60 seconds to perform a step of crosslinking the PVA molecules of the PVA layer on which iodine was adsorbed. The boric acid aqueous solution for crosslinking used in this crosslinking step had a boric acid content of 3 parts by weight with respect to 100 parts by weight of water and a potassium iodide content of 3 parts by weight with respect to 100 parts by weight of water. Is. Further, the obtained colored laminate is stretched 2.7 times in a boric acid aqueous solution at a stretching temperature of 70 ° C. in the same direction as the previous stretching in air, whereby the final stretching ratio is increased. The film was stretched by 5.4 times to obtain an optical film laminate including the test polarizer. The boric acid aqueous solution used in this stretching step has a boric acid content of 4.0 parts by weight with respect to 100 parts by weight of water and a potassium iodide content of 5 parts by weight with respect to 100 parts by weight of water. It is. The obtained optical film laminate was taken out from the boric acid aqueous solution, and the boric acid adhering to the surface of the PVA layer was washed with an aqueous solution containing 4 parts by weight of potassium iodide with respect to 100 parts by weight of water. The washed optical film laminate was dried by a drying process using hot air at 60 ° C. to obtain a polarizer having a thickness of 5 μm laminated on the PET film.

(Production of first polarizing plate with retardation plate)
For the polarizer having a thickness of 5 μm laminated on the PET film prepared by the above-described polarizer production example, the polarizer was prepared by the above-described method via a UV curable adhesive on the surface opposite to the PET. The retardation film 1 was bonded by a roll to roll. Furthermore, after peeling the PET film from this laminate, an acrylic protective film was bonded via a UV curable adhesive to produce a polarizing plate with a retardation plate.

(Production of second polarizing plate with retardation plate)
For the polarizer having a thickness of 5 μm laminated on the PET film prepared by the above-described polarizer production example, the polarizer was prepared by the above-described method via a UV curable adhesive on the surface opposite to the PET. The retardation film 1 was bonded by a roll to roll. Furthermore, after peeling a PET film from this laminate, a brightness enhancement film was bonded using an acrylic adhesive to produce a polarizing plate with a retardation plate.

(Production of first polarizing plate)
For the polarizer having a thickness of 5 μm laminated on the PET film produced by the above-described polarizer production example, an acrylic protective film is rolled on the surface opposite to the PET via a UV curable adhesive. Bonded with a roll. Furthermore, after peeling the PET film from this laminate, a brightness enhancement film was bonded using an acrylic pressure-sensitive adhesive to produce a polarizing plate.

(Production of second polarizing plate)
For the polarizer having a thickness of 5 μm laminated on the PET film produced by the above-described polarizer production example, an acrylic protective film is rolled on the surface opposite to the PET via a UV curable adhesive. Bonded with a roll. Furthermore, after peeling the PET film from this laminate, an acrylic protective film was bonded through a UV curable adhesive to produce a polarizing plate.

(Example 1)
A liquid crystal panel was taken out from a smartphone (iPhon 5 manufactured by Apple Inc., USA) equipped with an IPS liquid crystal cell, the polarizing plates arranged above and below the liquid crystal cell were removed, and the glass surfaces on both sides of the liquid crystal cell were washed. Subsequently, on the surface on the viewing side of the liquid crystal cell, the first retardation plate-attached polarizing plate produced by the above-described method, so that the absorption axis of the polarizer is orthogonal to the initial alignment direction of the liquid crystal cell. It laminated | stacked through the acrylic adhesive (thickness 20 micrometers). Next, on the surface of the liquid crystal cell on the light source side, the first polarizing plate produced by the method described above is acrylic so that the absorption axis direction of the polarizer and the initial alignment direction of the liquid crystal cell are parallel to each other. It laminated | stacked through the adhesive (thickness 20 micrometers), and obtained the liquid crystal panel.

(Heating warpage test)
The curvature of the panel after heating the liquid crystal panel on which the polarizing plate was laminated at 85 ° C. for 24 hours was visually confirmed. A mark indicates that no warpage occurred, and a mark indicates that the liquid crystal panel was warped.

(Heating brightness unevenness test)
After the heat treatment at 85 ° C. for 48 hours, the panel was placed on the influence panel and the backlight, and the brightness unevenness was confirmed. A sample in which no unevenness occurred was marked with ◯, and a sample with unevenness was marked with x.

(Examples 2 to 5)
In the same manner as in Example 1, a retardation film 2-5 was used instead of the retardation film 1 to produce a liquid crystal panel on which polarizing plates were laminated. Similarly, warping due to heating and luminance unevenness were confirmed.

Example 6
A polyvinyl alcohol film having an average polymerization degree of 2400 and a saponification degree of 99.9 mol% and a thickness of 30 μm was immersed in warm water at 30 ° C. for 60 seconds to swell. Next, the film was dyed while being immersed in an aqueous solution of 0.3% concentration of iodine / potassium iodide (weight ratio = 0.5 / 8) and stretched to 3.5 times. Then, it extended | stretched so that the total draw ratio might be 6 times in 65 degreeC borate ester aqueous solution. After extending | stretching, it dried for 3 minutes in 40 degreeC oven, and obtained the polarizer. TAC 25 μm hard-coated on one side of the obtained 12 μm polarizer and the retardation film 1 on the other side were bonded using a water-based adhesive. The liquid crystal panel was obtained by bonding the produced said polarizing plate on the visual recognition side similarly to Example 1. FIG. About the obtained liquid crystal panel, the curvature by heating and the brightness nonuniformity were confirmed.

(Example 7)
As in Example 1, the second polarizing plate produced by the above-described method is provided on the surface on the viewing side of the liquid crystal cell so that the absorption axis of the polarizer is parallel to the initial alignment direction of the liquid crystal cell. And an acrylic pressure-sensitive adhesive (thickness: 20 μm). Next, on the surface on the light source side of the liquid crystal cell, the second polarizing plate with a retardation plate prepared by the above method is set so that the absorption axis direction of the polarizer and the initial alignment direction of the liquid crystal cell are orthogonal to each other. Then, an acrylic pressure-sensitive adhesive (thickness 20 μm) was laminated to obtain a liquid crystal panel. About the obtained liquid crystal panel, the curvature by heating and the brightness nonuniformity were confirmed.

(Comparative Example 1)
A biaxially stretched polypropylene film (trade name “Treffan” (thickness 60 μm) manufactured by Toray Industries, Inc.) on both sides of a 100 μm-thick norbornene resin film (trade name “ZEONOR ZF14-100” manufactured by Nippon Zeon Co., Ltd.) It bonded together through the adhesive layer (thickness 15 micrometers). Thereafter, the longitudinal direction of the film was held with a roll stretching machine, and the film was stretched 1.38 times in an air circulation type thermostatic oven at 146 ° C. to prepare a retardation film 6. The obtained retardation film 6 had a thickness of 100 μm, Re = 270 nm, Rth = 135 nm, and Nz coefficient = 0.50.

The obtained retardation film 6 was laminated with an acrylic pressure-sensitive adhesive so that the slow axis of the retardation film 6 and the absorption axis of the polarizing plate were orthogonal to each other.
The liquid crystal panel was obtained by bonding the produced said polarizing plate on the visual recognition side similarly to Example 1. FIG. About the obtained liquid crystal panel, the curvature by heating and the brightness nonuniformity were confirmed.

(Comparative Example 2)
Using phosgene as the carbonate precursor, 2,2-bis (4-hydroxyphenyl) propane and 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane as the aromatic dihydric phenol component, According to a conventional method, a polycarbonate resin (number average molecular weight (Mn) = 33,000, Mw / Mn = 1.78) having a weight ratio of 4: 6 and a weight average molecular weight (Mw) of 60,000 was obtained. . 70 parts by weight of the above polycarbonate resin and 30 parts by weight of a styrene resin having a weight average molecular weight (Mw) of 1,300 [number average molecular weight (Mn) = 716, Mw / Mn = 1.78] (Sanyo Kasei Himer SB75) Was added to 300 parts by weight of dichloromethane and stirred and mixed at room temperature for 4 hours to obtain a transparent solution. This solution was cast on a glass plate, allowed to stand at room temperature for 15 minutes, then peeled off from the glass plate, dried in an oven at 80 ° C. for 10 minutes, and then at 120 ° C. for 20 minutes, and had a thickness of 55 μm and a glass transition temperature (Tg ) Obtained a polymer film of 140 ° C.

  A biaxially stretched polypropylene film [trade name “Trephan” (thickness: 60 μm) manufactured by Toray] was bonded to both sides of the polymer film (thickness: 55 μm) via an acrylic pressure-sensitive adhesive layer (thickness: 15 μm). Thereafter, the longitudinal direction of the film was held with a roll stretching machine, and the film was stretched 1.27 times in an air circulation type thermostatic oven at 147 ° C. to prepare a retardation film 8. The obtained retardation film 7 had a thickness of 55 μm, Re = 270 nm, Rth = 135 nm, and Nz coefficient = 0.50.

  The obtained retardation film 7 was laminated using an acrylic pressure-sensitive adhesive so that the slow axis of the retardation film 7 and the absorption axis of the polarizing plate were orthogonal to each other. The liquid crystal panel was obtained by bonding the produced said polarizing plate on the visual recognition side similarly to Example 1. FIG. About the obtained liquid crystal panel, the curvature by heating and the brightness nonuniformity were confirmed.

(Comparative Example 3)
A TAC of 25 μm that was hard-coated on one side of a polarizer having a thickness of 16 μm, and the retardation film 1 were bonded to the other side using a water-based adhesive. The liquid crystal panel was obtained by bonding the produced said polarizing plate on the visual recognition side similarly to Example 1. FIG. About the obtained liquid crystal panel, the curvature by heating and the brightness nonuniformity were confirmed.

(Measurement of transmittance and polarization degree of polarizer)
The single transmittance T, the parallel transmittance Tp, and the orthogonal transmittance Tc of the polarizer were measured using an ultraviolet-visible spectrophotometer (V7100 manufactured by JASCO Corporation). Here, the “parallel transmittance” is a transmittance measured in a state where two polarizers having the same configuration are stacked so that the absorption axes are parallel to each other, and the “orthogonal transmittance” It is the transmittance measured in a state where two polarizers having the same configuration are overlapped so that the absorption axes are orthogonal to each other. On the other hand, the “single transmittance” is the transmittance of one polarizer. These values of T, Tp, and Tc are Y values measured by a JIS Z 8701 2 degree visual field (C light source) and corrected for visibility. In the measurement, in order to facilitate the handling of the polarizer, the measurement was performed in a state where a protective layer (acrylic resin film or cycloolefin resin film) was bonded to the polarizer. Since the light absorption of the protective layer is negligibly small compared to the light absorption of the polarizer, the transmittance of the laminate in which the protective layer is laminated on the polarizer is defined as the transmittance of the polarizer.

The degree of polarization P was obtained by the following equation using the parallel transmittance and the orthogonal transmittance.
Degree of polarization P (%) = {(Tp−Tc) / (Tp + Tc)} × (1/2) × 100

(Evaluation method of orientation function of PVA)
As a measuring apparatus, a Fourier transform infrared spectrophotometer (FT-IR) (manufactured by Perkin Elmer, trade name: “SPECTRUM2000”) was used. The surface of the PVA resin layer was evaluated by measuring total reflection attenuation (ATR) using polarized light as measurement light. The orientation function was calculated according to the following procedure. Measurement was carried out with the measured polarized light at 0 ° and 90 ° with respect to the stretching direction. It calculated according to (Formula 1) described below using the intensity | strength of 2941cm < ^-1 > of the obtained spectrum. The following intensity I as a reference peak to 3330cm ^-1, using the value of 2941cm ^-1 / ^{3330cm -1.} Note that perfect orientation is obtained when f = 1, and random orientation when f = 0. The peak at 2941 cm ⁻¹ is said to be absorption due to vibration of the main chain (—CH 2 —) of PVA.
(Formula 1) f = (3 <cos ² θ> −1) / 2
= (1-D) / [c (2D + 1)]
Where c = (3 cos ² β−1) / 2
β = 90deg => f = -2 × (1-D) / (2D + 1)
θ: Molecular chain / stretch direction β: Molecular chain / transition dipole moment D = (I⊥) / (I //)
(The value of D increases as PVA is oriented.)
I⊥: Intensity when measured with polarized light incident in a direction perpendicular to the stretching direction I //: Intensity when measured with polarized light incident in a direction parallel to the stretching direction

(Phase difference measurement)
The retardation of the retardation film was measured using a trade name “KOBRA-WPR” manufactured by Oji Scientific Instruments. The film in-plane refractive index difference Δnxy was calculated by dividing Re defined by Re = (nx−ny) × d by the thickness d. The thickness direction retardation Rth is defined by Rth = (nx−nz) × d.

(Thickness measurement)
The thickness of the polarizer and the protective layer was measured using a digital micrometer (KC-351C manufactured by Anritsu Corporation). The thickness of the retardation film was measured using a spectrophotometer for thin film (trade name: MCPD2000) manufactured by Otsuka Electronics Co., Ltd.

(Measurement of photoelastic coefficient)
Using a spectroscopic ellipsometer [product name “M-220” manufactured by JASCO Corporation], the sample (size 2 cm × 10 cm) is sandwiched at both ends and stress (5 to 15 N) is applied to the phase difference at the center of the sample. The value (23 ° C.) was measured and calculated from the slope of the function of stress and phase difference value.

In order to prevent warping from occurring in a configuration in which an optical film such as a polarizer and a retardation film is bonded to an IPS liquid crystal display panel based on the results of the above-described examples and comparative examples, FIG. In the polarizer 103 according to the embodiment of the present invention, for example, the concentration of iodine with respect to the polyvinyl alcohol-based resin is 3% by weight or more, the orientation of the PVA molecules is 0.38 or more, and the degree of polarization is 99.8% or more. The retardation film 101 has a refractive index distribution in which the refractive indexes nx, ny, and nz in the x-axis, y-axis, and z-axis directions have a relationship of nx>nz> ny, for example. the thickness d is configured as the following monolayer films 20 [mu] m, the film in-plane refractive index difference Δnxy 5.5 × 10 ^-3 or more, 300 nm and Re defined as Re = (nx-ny) × d 100 The thickness is preferably 130 to 300 nm, particularly preferably 250 to 290 nm, and Nz defined as Nz = (nx−nz) / (nx−ny) is 0.3 to 0.8, more preferably 0.35 to 0.00. 75, particularly preferably 0.4 to 0.6, the photoelastic coefficient is 5 × 10 ⁻¹¹ or more, more preferably 1 × 10 ⁻¹⁰ or more, and has a slow axis in the width direction perpendicular to the longitudinal direction. It can be constituted as follows.

  In consideration of the results of the above examples and comparative examples, an optical film laminate including a polarizer, a retardation film and the like having the above characteristics is used for an IPS liquid crystal display panel, for example, FIG. In order to prevent the liquid crystal cell (T / P) 201 that is a liquid crystal display panel from warping when the IPS liquid crystal display device 200 according to the embodiment of the present invention shown in FIG. On the light side, the distance from the backlight side surface of the IPS liquid crystal display panel to the backlight side surface of the polarizer is 50 μm or less, and the distance from the viewing side surface of the IPS liquid crystal display panel to the protective layer side surface of the polarizer, A difference in distance from the backlight side surface of the IPS liquid crystal display panel to the backlight side surface of the polarizer may be 10 μm or less.

  Furthermore, IPS liquid crystal display devices according to other embodiments shown in FIGS. 3 to 5 can also be configured to have the same characteristics as described above.

  While the present invention has been illustrated and described in detail with reference to specific embodiments, the scope of protection of the present invention is not limited to the details of the illustrated embodiments, but is defined by the scope of the claims. It is determined by.

100 Optical film laminate 101, 204, 304, 412, 512 Retardation film 103, 207, 216, 307, 316 Polarizer 404, 415, 504, 515 Polarizer 104, 206, 208, 215, 217, 306, 308 , 315, 317 Adhesive layer 405, 414, 416, 505, 514, 516 Adhesive layer 105, 209, 214, 218, 309, 314, 318 Protective film 406, 417, 506, 517 Protective film 106, 202, 213 , 219, 302, 313, 319 Adhesive layer 402, 410, 418, 502, 510, 518 Adhesive layer 107 Release film 200, 300, 400, 500 IPS liquid crystal display device 201, 401 Liquid crystal cell (T / P)
203, 205, 303, 305, 411, 413, 511, 513 Undercoat layer 210, 407 Surface treatment (conductive) layer 310, 507 Surface treatment layer 211, 311, 408, 508 Interlayer filling layer 212, 312, 409, 509 Glass 220, 320, 419, 519 Brightness enhancement films 221, 321, 420, 520 Diffusers 222, 322, 421, 521 Backlight 301, 501 Liquid crystal cells 323, 522 Touch panel 403, 503 Coat layer or protective layer

Claims (9)

Iodine adsorbed in the form of a PVA polyiodine ion complex to a polyvinyl alcohol-based resin layer stretched in the longitudinal direction so as to have a thickness of 12 μm or less, and a PVA molecular chain oriented in the stretching direction of the polyvinyl alcohol-based resin layer A long web-like PVA-iodine polarizer containing
A long web-like retardation film directly bonded to one surface of the polarizer via a first adhesive layer;
A first pressure-sensitive adhesive layer disposed on the surface of the retardation film opposite to the polarizer;
A long web-like release film bonded to the surface of the first pressure-sensitive adhesive layer opposite to the retardation film;
A protective layer bonded to the surface of the polarizer opposite to the retardation film via a second adhesive layer,
The polarizer has a concentration of iodine of 3% by weight or more with respect to the polyvinyl alcohol resin, an orientation of PVA molecules of 0.38 or more, and a polarization degree of 99.8% or more.
The retardation film has a x-axis direction in which the in-plane refractive index is maximum, a y-axis direction in the film plane perpendicular to the x-axis, and a z-axis film thickness direction. The refractive index nx, ny, nz in the y-axis and z-axis directions has a refractive index distribution in which nx>nz> ny, and the thickness d is 20 μm or less, and the in-plane refractive index difference Δnxy Is 5.5 × 10 ⁻³ or more, Re defined as Re = (nx−ny) × d is 100 to 300 nm, and Nz defined as Nz = (nx−nz) / (nx−ny) is 0.00. 3 to 0.8, the photoelastic coefficient is 5 × 10 ⁻¹¹ or more, and has a slow axis in the width direction perpendicular to the longitudinal direction,
Each of the first and second adhesive layers has a thickness of 2 μm or less and an elastic modulus in the range of 1 × 10 ⁵ to 3 × 10 ⁹ Pa,
The protective layer, Ri 50μm der from thickness 10,
The retardation film includes a coating film of a birefringent layer forming material including a non-liquid crystalline material having a birefringence (Δnxz) in the thickness direction represented by Δnxz = nx′−nz ′ of 0.0007 or more,
The nx ′ is a refractive index in a direction (slow axis direction) in which the refractive index is maximum in the plane of the layer when the non-liquid crystalline material is a solidified layer,
The nz ′ is a refractive index in the thickness direction of the solidified layer perpendicular to each direction of the direction of the nx ′ and the direction (fast axis direction) perpendicular to the direction of the nx ′ in the plane of the solidified layer. continuous optical film laminate for IPS liquid crystal display device according to claim Rukoto Oh.   The long distance for an IPS liquid crystal display device according to claim 1, wherein a distance between the protective layer surface of the polarizer and a surface of the release film on the first adhesive layer side is 50 µm or less. Optical film laminate.   The roll of the elongate optical film laminated body by which the elongate optical film laminated body described in Claim 1 or 2 was wound by roll shape. An IPS liquid crystal display panel;
A viewing-side optical film laminate including at least a polarizer and a retardation film, disposed on the viewing side of the IPS liquid crystal display panel;
A backlight side optical film laminate including at least a polarizer and a brightness enhancement film, disposed on the backlight side of the IPS liquid crystal display panel,
The polarizer contained in the viewing-side optical film laminate has a polyvinyl alcohol resin layer stretched in a uniaxial direction so that the thickness is 12 μm or less, and PVA oriented in the stretch direction of the polyvinyl alcohol resin layer. A long web-like PVA iodine-based polarizer containing iodine adsorbed on the molecular chain in the form of a PVA polyiodine ion complex;
The polarizer contained in the viewing-side optical film laminate has an iodine concentration of 3% by weight or more, a PVA molecule orientation of 0.38 or more, and a polarization degree of 99.8% or more.
The retardation film has a x-axis direction in which the in-plane refractive index is maximum, a y-axis direction in the film plane perpendicular to the x-axis, and a z-axis film thickness direction. The refractive index nx, ny, nz in the y-axis and z-axis directions has a refractive index distribution in which nx>nz> ny, and the thickness d is 20 μm or less, and the in-plane refractive index difference Δnxy Is 5.5 × 10 ⁻³ or more, Re defined as Re = (nx−ny) × d is 100 to 300 nm, and Nz defined as Nz = (nx−nz) / (nx−ny) is 0.00. 3 to 0.8, the photoelastic modulus is 5 × 10 ⁻¹¹ or more, the slow axis is substantially perpendicular to the absorption axis of the polarizer, the thickness is 2 μm or less, and the elastic modulus is 1 × 10 ^5. To 3 × 10 ⁹ Pa directly through the adhesive layer of the viewing-side optical film laminate Bonded to the polarizer,
The retardation film is bonded to the viewing-side surface of the IPS liquid crystal display panel via an adhesive layer, and the polarizing film is formed on the viewing-side surface of the IPS liquid crystal display panel from the viewing-side surface of the IPS liquid crystal display panel. The distance to the protective layer side surface of the child is 50 μm or less,
The polarizer included in the backlight-side optical film laminate was oriented in the stretching direction of the polyvinyl alcohol-based resin layer stretched in a uniaxial direction so that the thickness was 12 μm or less, and the polyvinyl alcohol-based resin layer. A PVA-iodine-based polarizer comprising iodine adsorbed on the PVA molecular chain in the form of a PVA polyiodine ion complex,
The polarizer included in the backlight-side optical film laminate has an iodine concentration of 3% by weight or more, a PVA molecule orientation of 0.38 or more, and a polarization degree of 99.8% or more. The surface is bonded to the protective layer through an adhesive layer having a thickness of 2 μm or less and an elastic modulus in the range of 1 × 10 ⁵ to 3 × 10 ⁹ Pa,
The protective layer is bonded to the backlight side surface of the IPS liquid crystal display panel via an adhesive layer, and on the backlight side of the IPS liquid crystal display panel, from the backlight side surface of the IPS liquid crystal display panel, The distance to the backlight side surface of the polarizer is 50 μm or less,
The difference between the distance from the viewing side surface of the IPS liquid crystal display panel to the protective layer side surface of the polarizer and the distance from the backlight side surface of the IPS liquid crystal display panel to the backlight side surface of the polarizer is 10 μm or less. der is,
The retardation film includes a coating film of a birefringent layer forming material including a non-liquid crystalline material having a birefringence (Δnxz) in the thickness direction represented by Δnxz = nx′−nz ′ of 0.0007 or more,
The nx ′ is a refractive index in a direction (slow axis direction) in which the refractive index is maximum in the plane of the layer when the non-liquid crystalline material is a solidified layer,
The nz ′ is a refractive index in the thickness direction of the solidified layer perpendicular to each direction of the direction of the nx ′ and the direction (fast axis direction) perpendicular to the direction of the nx ′ in the plane of the solidified layer. Oh IPS liquid crystal display device according to claim Rukoto.   5. The IPS liquid crystal display device according to claim 4, wherein the polarizer included in the viewing-side optical film laminate has a protective film on an opposite surface to the retardation film via an adhesive layer. An IPS liquid crystal display device, wherein: 6. The IPS liquid crystal display device according to claim 5, wherein the adhesive layer has a thickness of 2 μm or less and an elastic modulus of 1 × 10 ⁵ to 3 × 10 ⁹ . An IPS liquid crystal display panel;
A backlight-side optical film laminate including at least a polarizer and a retardation film, disposed on the backlight side of the IPS liquid crystal display panel;
A viewing-side optical film laminate including at least a polarizer, disposed on the viewing side of the IPS liquid crystal display panel,
The polarizer included in the backlight-side optical film laminate was oriented in the stretching direction of the polyvinyl alcohol-based resin layer stretched in a uniaxial direction so that the thickness was 12 μm or less, and the polyvinyl alcohol-based resin layer. A long web-like PVA iodine-based polarizer containing iodine adsorbed on the PVA molecular chain in the form of a PVA polyiodine ion complex,
The polarizer contained in the backlight-side optical film laminate has an iodine concentration of 3% by weight or more, a PVA molecule orientation of 0.38 or more, and a polarization degree of 99.8% or more,
The retardation film has a x-axis direction in which the in-plane refractive index is maximum, a y-axis direction in the film plane perpendicular to the x-axis, and a z-axis film thickness direction. The refractive index nx, ny, nz in the y-axis and z-axis directions has a refractive index distribution in which nx>nz> ny, and the thickness d is 20 μm or less, and the in-plane refractive index difference Δnxy Is 5.5 × 10 ⁻³ or more, Re defined as Re = (nx−ny) × d is 100 to 300 nm, and Nz defined as Nz = (nx−nz) / (nx−ny) is 0.00. 3 to 0.8, the photoelastic modulus is 5 × 10 ⁻¹¹ or more, the slow axis is substantially perpendicular to the absorption axis of the polarizer, the thickness is 2 μm or less, and the elastic modulus is 1 × 10 ^5. Directly from the backlight side optical film through an adhesive layer of 3 × 10 ⁹ Pa Bonded to the polarizer of the laminate,
The retardation film is bonded to the backlight side surface of the IPS liquid crystal display panel via an adhesive layer, and the backlight side surface of the IPS liquid crystal display panel is the backlight side surface of the IPS liquid crystal display panel. The distance from the backlight side surface of the polarizer is 50 μm or less,
The polarizer contained in the viewing-side optical film laminate has a polyvinyl alcohol resin layer stretched in a uniaxial direction so that the thickness is 12 μm or less, and PVA oriented in the stretch direction of the polyvinyl alcohol resin layer. A PVA-iodine-based polarizer comprising iodine adsorbed on the molecular chain in the form of a PVA polyiodine ion complex,
The polarizer included in the viewing-side optical film laminate has an iodine concentration of 3% by weight or more, a PVA molecule orientation of 0.38 or more, and a polarization degree of 99.8% or more. Is bonded to the protective layer through an adhesive layer having a thickness of 2 μm or less and an elastic modulus in the range of 1 × 10 ⁵ to 3 × 10 ⁹ Pa,
The protective layer is bonded to the viewing side surface of the IPS liquid crystal display panel via an adhesive layer, and on the viewing side of the IPS liquid crystal display panel, from the viewing side surface of the IPS liquid crystal display panel, The distance to the viewing side surface is 50 μm or less,
The difference between the distance from the backlight side surface of the IPS liquid crystal display panel to the protective layer side surface of the polarizer and the distance from the viewing side surface of the IPS liquid crystal display panel to the viewing side surface of the polarizer is 10 μm or less. Oh it is,
The retardation film includes a coating film of a birefringent layer forming material including a non-liquid crystalline material having a birefringence (Δnxz) in the thickness direction represented by Δnxz = nx′−nz ′ of 0.0007 or more,
The nx ′ is a refractive index in a direction (slow axis direction) in which the refractive index is maximum in the plane of the layer when the non-liquid crystalline material is a solidified layer,
The nz ′ is a refractive index in the thickness direction of the solidified layer perpendicular to each direction of the direction of the nx ′ and the direction (fast axis direction) perpendicular to the direction of the nx ′ in the plane of the solidified layer. Oh IPS liquid crystal display device according to claim Rukoto.   The IPS liquid crystal display device according to claim 7, wherein the polarizer included in the backlight-side optical film laminate has an acrylic pressure-sensitive adhesive layer on a surface opposite to the retardation film. An IPS liquid crystal display device, wherein a brightness enhancement film is bonded. 9. The IPS liquid crystal display device according to claim 8, wherein the adhesive layer has a thickness of 2 μm or less and an elastic modulus of 1 × 10 ⁵ to 3 × 10 ⁹ .

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