WO2018008523A1 - Optical member and liquid crystal display device - Google Patents

Optical member and liquid crystal display device Download PDF

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Publication number
WO2018008523A1
WO2018008523A1 PCT/JP2017/023979 JP2017023979W WO2018008523A1 WO 2018008523 A1 WO2018008523 A1 WO 2018008523A1 JP 2017023979 W JP2017023979 W JP 2017023979W WO 2018008523 A1 WO2018008523 A1 WO 2018008523A1
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WO
WIPO (PCT)
Prior art keywords
protective cover
optical member
liquid crystal
film
display device
Prior art date
Application number
PCT/JP2017/023979
Other languages
French (fr)
Japanese (ja)
Inventor
岳仁 淵田
弘明 麓
勝則 高田
▲吉▼紹 北村
Original Assignee
日東電工株式会社
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Priority claimed from JP2017125802A external-priority patent/JP2018013774A/en
Application filed by 日東電工株式会社 filed Critical 日東電工株式会社
Publication of WO2018008523A1 publication Critical patent/WO2018008523A1/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/13363—Birefringent elements, e.g. for optical compensation

Definitions

  • the present invention relates to an optical member and a liquid crystal display device having the optical member.
  • polarized sunglasses Sunglasses with polarization characteristics
  • the display light of the liquid crystal display device is absorbed by the polarized sunglasses depending on the posture of the viewer, and the visibility decreases.
  • Patent Document 1 a white light-emitting diode is used as a backlight of a liquid crystal display device, and a polymer film having a retardation of 3000 to 30000 nm is provided on the viewer side of the polarizer.
  • a visibility improving method is described in which the angle formed with the slow axis is about 45 °. According to the visibility improvement method of patent document 1, it is supposed that the visibility when a screen is observed through polarized sunglasses can be improved.
  • the display panel is covered with a transparent protective cover such as plastic.
  • a transparent protective cover such as plastic.
  • This invention is made in view of said subject, Comprising:
  • the objective is to provide the optical member which can suppress the fall of visibility when visually recognizing the liquid crystal display device with a protective cover through polarized sunglasses. is there.
  • the optical member of the present invention includes a polarizing film, a high retardation layer, and a protective cover in this order, the in-plane retardation of the high retardation layer is 3000 nm to 30000 nm, the slow axis of the high retardation layer, and the polarization
  • the angle formed with the absorption axis of the film is 40 ° to 50 °
  • the in-plane retardation of the protective cover is 7000 nm or less.
  • the in-plane phase difference of the protective cover is 1000 nm or less.
  • an angle formed between the slow axis of the protective cover and the absorption axis of the polarizing film is ⁇ 5 ° to 5 ° or 85 ° to 95 °.
  • the angle formed by the slow axis of the protective cover and the absorption axis of the polarizing film is 40 ° to 50 °, and the slow axis of the protective cover and the slow axis of the high retardation layer Is an angle of ⁇ 5 ° to 5 ° or 85 ° to 95 °.
  • the thickness of the protective cover is 1000 ⁇ m or more.
  • S ⁇ T The value is 400 or more.
  • an adhesive is filled between the protective cover and the high retardation layer.
  • an antireflection film is laminated on the side of the protective cover opposite to the polarizing film.
  • the liquid crystal display device of the present invention includes the optical member.
  • nx is the refractive index in the direction in which the in-plane refractive index is maximum (that is, the slow axis direction)
  • “ny” is the direction orthogonal to the slow axis in the plane (that is, the fast phase). (Nz direction)
  • “nz” is the refractive index in the thickness direction.
  • FIG. 1 is a cross-sectional view of an optical member according to one embodiment of the present invention.
  • the optical member 10 has a polarizing film 1, a high retardation layer 2, and a protective cover 3 in this order, and the polarizing film 1 and the high retardation layer 2 are attached via an adhesive 4.
  • the in-plane retardation of the high retardation layer 2 is 3000 nm to 30000 nm
  • the in-plane retardation of the protective cover 3 is 7000 nm or less
  • the angle formed between the slow axis of the high retardation layer 2 and the absorption axis of the polarizing film 1 is 40 ° to 50 °.
  • the optical member 10 of the present invention can be mounted on a liquid crystal display device.
  • the optical member 10 By providing the optical member 10 on the viewer side of the liquid crystal cell of the liquid crystal display device, the visibility when the display screen of the liquid crystal display device is observed through polarized sunglasses can be improved. Specifically, a decrease in front luminance and a change in hue (color shift) according to the viewing angle can be suppressed.
  • FIG. 2 is a cross-sectional view of an optical member according to another embodiment of the present invention.
  • the optical member 11 shown in FIG. 2 has a structure in which the high retardation layer 2 and the protective cover 3 are bonded together with an interlayer filling adhesive 5 interposed therebetween.
  • FIG. 3 is a cross-sectional view of an optical member according to still another embodiment of the present invention.
  • the antireflection film 6 may be provided on the viewer side of the protective cover 3.
  • an antireflection film usually used in the industry can be employed.
  • a layer made of a medium refractive index material, a layer made of a high refractive index material, and a layer made of a low refractive index material. can be employed.
  • the polarizing film 1 has a laminated structure of a polarizer and a protective layer. Specifically, in the laminated structure of the polarizing film 1, the high retardation layer 2, and the protective cover 3, a protective layer (not shown) may be provided on the protective cover 3 side of the polarizer. Further, another protective layer (not shown: hereinafter also referred to as an inner protective layer) may be provided on the opposite side of the polarizer from the protective cover 3.
  • the resin film forming the polarizer may be a single-layer resin film or a laminate of two or more layers.
  • polarizers composed of a single-layer resin film include hydrophilic polymer films such as polyvinyl alcohol (PVA) films, partially formalized PVA films, and ethylene / vinyl acetate copolymer partially saponified films.
  • PVA polyvinyl alcohol
  • polyene-based oriented films such as those subjected to dyeing treatment and stretching treatment with dichroic substances such as iodine and dichroic dyes, PVA dehydrated products and polyvinyl chloride dehydrochlorinated products.
  • a polarizer obtained by dyeing a PVA film with iodine and uniaxially stretching is used because of excellent optical properties.
  • the dyeing with iodine is performed, for example, by immersing a PVA film in an aqueous iodine solution.
  • the stretching ratio of the uniaxial stretching is preferably 3 to 7 times.
  • the stretching may be performed after the dyeing treatment or may be performed while dyeing. Moreover, you may dye
  • the PVA film is subjected to swelling treatment, crosslinking treatment, washing treatment, drying treatment and the like. For example, by immersing the PVA film in water and washing it before dyeing, not only can the surface of the PVA film be cleaned of dirt and anti-blocking agents, but the PVA film can be swollen to cause uneven staining. Can be prevented.
  • a polarizer obtained by using a laminate a laminate of a resin substrate and a PVA resin layer (PVA resin film) laminated on the resin substrate, or a resin substrate and the resin
  • a polarizer obtained by using a laminate with a PVA resin layer applied and formed on a substrate examples thereof include a polarizer obtained by using a laminate with a PVA resin layer applied and formed on a substrate.
  • a polarizer obtained by using a laminate of a resin base material and a PVA resin layer applied and formed on the resin base material may be obtained by, for example, applying a PVA resin solution to a resin base material and drying it.
  • a PVA-based resin layer is formed thereon to obtain a laminate of a resin base material and a PVA-based resin layer; the laminate is stretched and dyed to make the PVA-based resin layer a polarizer; obtain.
  • stretching typically includes immersing the laminate in an aqueous boric acid solution and stretching.
  • the stretching may further include, if necessary, stretching the laminate in the air at a high temperature (for example, 95 ° C. or higher) before stretching in the aqueous boric acid solution.
  • the obtained resin base material / polarizer laminate may be used as it is (that is, the resin base material may be used as a protective layer of the polarizer), and the resin base material is peeled from the resin base material / polarizer laminate.
  • Any appropriate protective layer according to the purpose may be laminated on the release surface. Details of a method for manufacturing such a polarizer are described in, for example, Japanese Patent Application Laid-Open No. 2012-73580. This publication is incorporated herein by reference in its entirety.
  • the thickness of the polarizer is typically 1 ⁇ m to 80 ⁇ m.
  • the upper limit of the thickness of the polarizer is preferably 50 ⁇ m, more preferably 35 ⁇ m, and particularly preferably 30 ⁇ m.
  • the lower limit of the thickness of the polarizer is preferably 1 ⁇ m, more preferably 3 ⁇ m.
  • the protective layer is formed of any suitable film that can be used as a protective layer for a polarizer.
  • the material as the main component of the film include cellulose resins such as triacetyl cellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyethersulfone-based, and polysulfone-based materials.
  • transparent resins such as polystyrene, polynorbornene, polyolefin, (meth) acryl, and acetate.
  • thermosetting resins such as (meth) acrylic, urethane-based, (meth) acrylurethane-based, epoxy-based, and silicone-based or ultraviolet curable resins are also included.
  • a glassy polymer such as a siloxane polymer is also included.
  • a polymer film described in JP-A-2001-343529 (WO01 / 37007) can also be used.
  • a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in the side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and nitrile group in the side chain for example, a resin composition having an alternating copolymer of isobutene and N-methylmaleimide and an acrylonitrile / styrene copolymer can be mentioned.
  • the polymer film can be, for example, an extruded product of the resin composition.
  • the protective layer may be subjected to surface treatment such as hard coat treatment, antireflection treatment, anti-sticking treatment, and antiglare treatment as necessary. Further / or, if necessary, the protective layer may be treated to improve visibility when viewed through polarized sunglasses (typically, an (elliptical) circular polarization function is added, an ultra-high phase difference is applied. Granting). By performing such processing, it is possible to improve the visibility when the display screen of the liquid crystal display device on which the optical member 10 is mounted is viewed through the polarized sunglasses.
  • surface treatment such as hard coat treatment, antireflection treatment, anti-sticking treatment, and antiglare treatment as necessary. Further / or, if necessary, the protective layer may be treated to improve visibility when viewed through polarized sunglasses (typically, an (elliptical) circular polarization function is added, an ultra-high phase difference is applied. Granting). By performing such processing, it is possible to improve the visibility when the display screen of the liquid crystal display device on which the optical member 10 is mounted is viewed
  • the thickness of the protective layer is typically 5 mm or less, preferably 1 mm or less, more preferably 1 ⁇ m to 500 ⁇ m, and even more preferably 5 ⁇ m to 150 ⁇ m.
  • the thickness of the protective layer is a thickness including the thickness of the surface treatment layer.
  • the inner protective layer is preferably optically isotropic.
  • “optically isotropic” means that the in-plane retardation Re (550) is 0 nm to 10 nm and the thickness direction retardation Rth (550) is ⁇ 10 nm to +10 nm.
  • the inner protective layer can be composed of any suitable material as long as it is optically isotropic. The material can be appropriately selected from the materials described above with respect to the protective layer, for example.
  • the thickness of the inner protective layer is preferably 5 ⁇ m to 200 ⁇ m, more preferably 10 ⁇ m to 100 ⁇ m, and still more preferably 15 ⁇ m to 95 ⁇ m.
  • Adhesive As the adhesive 4, any appropriate adhesive can be adopted.
  • the pressure-sensitive adhesive 4 is typically formed of an acrylic pressure-sensitive adhesive.
  • the high retardation layer 2 is made of a transparent material having birefringence.
  • the in-plane retardation of the high retardation layer 2 is 3000 nm or more and 30000 nm or less, and more preferably 10,000 nm or more.
  • the thickness of the high retardation layer 2 is arbitrary, preferably 25 ⁇ m to 500 ⁇ m, and more preferably 35 ⁇ m to 350 ⁇ m.
  • the angle formed by the slow axis of the high retardation layer 2 and the absorption axis of the polarizing film 1 is preferably 40 ° to 50 °, more preferably 42 ° to 48 °, and particularly preferably about 45 °. .
  • the high retardation layer 2 can be formed of any appropriate material.
  • the material include polyesters such as polyethylene terephthalate and polyethylene naphthalate, polycarbonate, polystyrene, polyether ether ketone, polyphenylene sulfide, and cycloolefin polymer.
  • polyesters typified by polyethylene terephthalate have a large intrinsic birefringence and can be suitably used because a large in-plane retardation can be obtained relatively easily even when the thickness is small.
  • the protective cover 3 is made of a transparent plastic material having birefringence.
  • the in-plane retardation of the protective cover 3 is 7000 nm or less.
  • the upper limit of the in-plane retardation of the protective cover 3 is preferably 5000 nm, more preferably 3000 nm, and particularly preferably 1000 nm.
  • the in-plane retardation of the protective cover 3 is greater than 0 nm.
  • the angle formed between the slow axis of the protective cover 3 and the absorption axis of the polarizing film 1 is not particularly limited.
  • the angle formed by the slow axis of the protective cover 3 and the absorption axis of the polarizing film 1 is typically substantially 0 °, substantially 45 °, or substantially 90 °.
  • the angle formed by the slow axis of the protective cover 3 and the absorption axis of the polarizing film 1 is preferably ⁇ 5 ° to 5 °, 40 ° to 50 °, or 85 ° to 95 °, more preferably. Is from -3 ° to 3 °, from 42 ° to 48 °, or from 87 ° to 93 °, particularly preferably about 0 °, about 45 °, or about 90 °.
  • the angle formed between the slow axis of the protective cover 3 and the absorption axis of the polarizing film 1 is substantially 45 °
  • the angle formed between the slow axis of the protective cover 3 and the slow axis of the high retardation layer 2 is substantially 0 ° or substantially 90 °.
  • the angle formed by the slow axis of the protective cover 3 and the absorption axis of the polarizing film 1 is preferably ⁇ 5 ° to 5 ° or 85 ° to 95 °, more preferably ⁇ 3 ° to 3 °. Or from 87 ° to 93 °, particularly preferably about 0 ° or about 90 °.
  • the thickness of the protective cover 3 is preferably 1000 ⁇ m or more, more preferably 2000 ⁇ m or more. By setting the thickness of the protective cover 3 to 1000 ⁇ m or more, the mechanical strength necessary for protecting the liquid crystal cell can be realized when the optical member 10 is provided on the viewer side of the liquid crystal cell of the liquid crystal display device. it can. Moreover, it is preferable that the thickness of the protective cover 3 is 4000 micrometers or less. Thereby, the liquid crystal display device can be made compact, and the protective cover 3 can be applied to a liquid crystal display device with a touch panel.
  • the value of S ⁇ T indicating the strength of the protective cover is preferably 400 or more. Preferably it is 500 or more, More preferably, it is 600 or more. On the other hand, the upper limit value of S ⁇ T is preferably 4000, and more preferably 2000.
  • the bending strength of the protective cover can be measured according to the bending test method of ASTM-D790.
  • the protective cover 3 may be bonded to the polarizing film 1 without leaving a gap, or may be provided with a gap between the protective cover 3 and the polarizing film 1.
  • the in-plane retardation of the high retardation layer 2 is 3000 nm to 30000 nm, and the angle formed by the slow axis of the high retardation layer 2 and the absorption axis of the polarizing film 1 is 40 ° to 50 °.
  • the in-plane phase difference of the protective cover 3 is 7000 nm or less.
  • the interlayer filling pressure-sensitive adhesive 5 may be an acrylic pressure-sensitive adhesive containing an acrylic polymer.
  • the content of the acrylic polymer in the interlayer filling adhesive 5 is not particularly limited, but is preferably 96% to 100% by weight, more preferably 98% to 100% by weight from the viewpoint of odor.
  • the acrylic polymer preferably has (meth) acrylic acid alkyl ester and / or (meth) acrylic acid alkoxyalkyl ester having a linear or branched alkyl group as an essential monomer component (monomer component). It is a structured acrylic polymer.
  • the specific constitution of the interlayer filling pressure-sensitive adhesive 5 is preferably 84 to 94% by weight of 2-ethylhexyl acrylate (2EHA), acrylic acid based on the total amount (100% by weight) of monomer components constituting the acrylic polymer.
  • This is an acrylic pressure-sensitive adhesive layer containing an acrylic polymer composed of a monomer component containing 5 to 15% by weight of (AA) and 0.03 to 0.15% by weight of dipentaerythritol hexaacrylate (DPHA).
  • i-OA isooctyl acrylate
  • An acrylic pressure-sensitive adhesive layer containing an acrylic polymer composed of a monomer component containing 5 to 15% by weight of acrylic acid (AA) and 0.03 to 0.15% by weight of dipentaerythritol hexaacrylate (DPHA) .
  • the thickness of the interlayer filling adhesive 5 is preferably 25 ⁇ m to 500 ⁇ m, more preferably 75 ⁇ m to 350 ⁇ m.
  • the 180 ° peeling adhesive strength (referred to as “adhesive strength (23 ° C.)”) at 23 ° C. of the interlayer filling adhesive 5 at 23 ° C. is preferably 5 N / 20 mm or more, more preferably 8 N / 20 mm or more. It is. By setting the adhesive force (23 ° C.) to 5 N / 20 mm or more, generation of delay bubbles (bubbles appearing at the interface with the protective cover) is suppressed.
  • the adhesive strength (23 ° C.) is measured by performing a 180 ° peel test (according to JIS Z0237 (2000), tensile speed: 300 mm / min) using a protective cover as an adherend at 23 ° C. Can do.
  • a liquid crystal display device includes a liquid crystal cell and the optical member according to any of items A to F arranged on the viewing side of the liquid crystal cell.
  • the optical member is disposed so that the polarizing film is on the liquid crystal cell side.
  • Example 1> 1 Production of Polarizing Plate A polyvinyl alcohol film having a thickness of 80 ⁇ m was stretched up to 3 times while being dyed for 1 minute in an iodine solution of 0.3% concentration at 30 ° C. between rolls having different speed ratios. Thereafter, the total draw ratio was stretched to 6 times while being immersed in an aqueous solution containing 60% at 4% concentration of boric acid and 10% concentration of potassium iodide for 0.5 minutes. Next, after washing by immersing in an aqueous solution containing potassium iodide at 30 ° C. and 1.5% concentration for 10 seconds, drying was performed at 50 ° C. for 4 minutes to obtain a polarizer. A polarizing plate (polarizing film) was prepared by bonding a saponified 80 ⁇ m thick triacetyl cellulose film on both surfaces of the polarizer with a polyvinyl alcohol adhesive.
  • Optical Member As a protective cover, a plastic cover (product name “NF2000”, manufactured by Mitsubishi Gas Chemical Company) having an in-plane retardation of 877 nm and a thickness of 1500 ⁇ m made of polycarbonate resin was used. As the high retardation layer, a high retardation film (product name “COSMO SHINE SRF” manufactured by Toyobo Co., Ltd.) having an in-plane retardation of 8400 nm and a thickness of 80 ⁇ m made of polyethylene terephthalate resin was used.
  • a plastic cover product name “NF2000”, manufactured by Mitsubishi Gas Chemical Company
  • COSMO SHINE SRF manufactured by Toyobo Co., Ltd.
  • the high retardation film and the polarizing plate were bonded together via an acrylic pressure-sensitive adhesive so that the angle ⁇ formed by the slow axis of the high retardation film and the absorption axis of the polarizing plate was 45 °. Furthermore, with respect to the high retardation film, the plastic cover is formed between the slow axis of the plastic cover and the absorption axis of the polarizing plate via an interlayer filling adhesive (product name “CS9864” manufactured by Nitto Denko Corporation). The optical member was obtained by pasting together so that the angle ⁇ was 0 °.
  • Example 2 An optical member was obtained in the same manner as in Example 1 except that a plastic cover (product name “PC1151” manufactured by Teijin Ltd.) with a thickness of 2000 ⁇ m made of polycarbonate resin was used as the protective cover. It was.
  • a plastic cover product name “PC1151” manufactured by Teijin Ltd.
  • T thickness of the protective cover
  • Example 3 Example 1 except that a plastic cover (product name “MR200” manufactured by Mitsubishi Rayon Co., Ltd.) having a thickness of 1500 ⁇ m made of polymethyl methacrylate resin was used as the protective cover. Thus, an optical member was obtained.
  • the bending strength of the protective cover measured according to the bending test method of ASTM-D790 is S (kgf / cm 2 ) and the thickness of the protective cover is T (mm)
  • the strength of the protective cover (S ⁇ T ) was 1425.
  • Example 4 As a protective cover, an in-plane retardation of 112.4 nm and a plastic cover with a thickness of 1500 ⁇ m made of a laminated structure of polymethyl methacrylate resin / polycarbonate resin / polymethyl methacrylate resin (product name “MT3LTR” manufactured by Kuraray Co., Ltd.) An optical member was obtained in the same manner as in Example 1 except that was used.
  • the bending strength of the protective cover measured according to the bending test method of ASTM-D790 is S (kgf / cm 2 ) and the thickness of the protective cover is T (mm), the strength of the protective cover (S ⁇ T ) was 1425.
  • ⁇ Comparative Example 1> Other than using a plastic cover (product name “HMR551T”, manufactured by Mitsubishi Gas Chemical Co., Inc.) having a thickness of 1450 ⁇ m and having a laminated structure of polymethyl methacrylate resin and polycarbonate resin as an in-plane retardation of 7605 nm. Obtained an optical member in the same manner as in Example 1.
  • the bending strength of the protective cover measured according to the bending test method of ASTM-D790 is S (kgf / cm 2 ) and the thickness of the protective cover is T (mm), the strength of the protective cover (S ⁇ T ) was 1377.
  • a light source, an optical member, and a polarizing plate are arranged in the same manner as the measurement of front luminance, and a conoscope (manufactured by AUTRONIC MELCHERS Co., Ltd.) is used in a polar angle of 0 ° to 60 ° Hue, x value, and y value at azimuth angles of 0 ° to 360 ° were measured.
  • a conoscope manufactured by AUTRONIC MELCHERS Co., Ltd.
  • the x value and y value at two arbitrary points are (x A , y A ) and (x B , y B ), and the following formula: ⁇ (x A ⁇ x B ) 2 + The maximum value of (y A -y B ) 2 ⁇ 1/2 was taken as the ⁇ xy value.
  • the polarizing plate was arranged so that the angle formed by the absorption axis of the polarizer and the absorption axis of the polarizer of the optical member was 45 °.
  • Table 1 shows the measurement results of the front luminance and color shift of the optical members of Examples 1 to 4 and Comparative Example 1
  • Table 2 shows the measurement results of the front luminance and color shift of the optical members of Comparative Examples 2 to 6.
  • Tables 1 and 2 show an xy chromaticity diagram (horizontal axis: x value, vertical axis: y value) and a color shift amount ( ⁇ xy value) as measurement results of the color shift.
  • the optical member of the present invention is suitably used for a liquid crystal display device mounted on a mobile phone, a portable information terminal, a digital camera, a video camera, a portable game machine, a car navigation system, a copy machine, a printer, a fax machine, a watch, a microwave oven, and the like. It is done.

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  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Mathematical Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Polarising Elements (AREA)

Abstract

Provided is an optical member which makes it possible to prevent reductions to visibility that occur when a liquid crystal display device having a protective cover is viewed through polarized sunglasses. This optical member is provided with, in order, a polarizing film, a high retardation layer, and a protective cover. The in-plane retardation of the high retardation layer is 3000 nm to 30000 nm, the angle formed by the slow axis of the high retardation layer and the absorption axis of the polarizing film is 40° to 50°, and the in-plane retardation of the protective cover is no more than 7000 nm.

Description

光学部材及び液晶表示装置Optical member and liquid crystal display device
　本発明は、光学部材及び光学部材を有する液晶表示装置に関する。 The present invention relates to an optical member and a liquid crystal display device having the optical member.
　日差しの強い環境下での眩しさを低減するために、偏光特性を有するサングラス（偏光サングラス）が用いられる。しかしながら、偏光サングラスを掛けた状態で液晶表示装置を視認した場合、観者の姿勢によっては液晶表示装置の表示光が偏光サングラスに吸収されてしまい、視認性が低下する。 サ ン グ ラ ス Sunglasses with polarization characteristics (polarized sunglasses) are used to reduce glare in an environment with strong sunlight. However, when the liquid crystal display device is viewed with the polarized sunglasses on, the display light of the liquid crystal display device is absorbed by the polarized sunglasses depending on the posture of the viewer, and the visibility decreases.
　特許文献１には、液晶表示装置のバックライトとして白色発光ダイオードを用いるとともに、偏光子の観者側に、３０００～３００００ｎｍのリタデーションを有する高分子フィルムを、偏光子の吸収軸と高分子フィルムの遅相軸とのなす角が凡そ４５°となるように配して用いる視認性改善方法が記載されている。特許文献１の視認性改善方法によれば、偏光サングラスを通して画面を観察したときの視認性を改善することができるとされている。 In Patent Document 1, a white light-emitting diode is used as a backlight of a liquid crystal display device, and a polymer film having a retardation of 3000 to 30000 nm is provided on the viewer side of the polarizer. A visibility improving method is described in which the angle formed with the slow axis is about 45 °. According to the visibility improvement method of patent document 1, it is supposed that the visibility when a screen is observed through polarized sunglasses can be improved.
特開２０１１－２１５６４６号公報JP 2011-215646 A
　例えば、カーナビゲーションシステムに搭載された液晶表示装置は、表示パネルがプラスチックなどの透明な保護カバーで覆われている。特許文献１の視認性改善方法で用いられる高分子フィルムをカーナビゲーションシステム用の液晶表示装置に適用した場合、保護カバーの光学特性の影響を受けて視認性が低下する場合がある。 For example, in a liquid crystal display device mounted on a car navigation system, the display panel is covered with a transparent protective cover such as plastic. When the polymer film used in the visibility improving method of Patent Document 1 is applied to a liquid crystal display device for a car navigation system, the visibility may be lowered due to the influence of the optical characteristics of the protective cover.
　本発明は、上記の課題に鑑みなされたものであって、その目的は、偏光サングラスを通して保護カバー付きの液晶表示装置を視認したときの視認性の低下を抑制し得る光学部材を提供することにある。 This invention is made in view of said subject, Comprising: The objective is to provide the optical member which can suppress the fall of visibility when visually recognizing the liquid crystal display device with a protective cover through polarized sunglasses. is there.
　本発明の光学部材は、偏光フィルムと高位相差層と保護カバーとをこの順に有し、前記高位相差層の面内位相差が３０００ｎｍ～３００００ｎｍであり、前記高位相差層の遅相軸と前記偏光フィルムの吸収軸とのなす角度が４０°～５０°であり、前記保護カバーの面内位相差が７０００ｎｍ以下である。
　１つの実施形態においては、前記保護カバーの面内位相差が１０００ｎｍ以下である。
　１つの実施形態においては、前記保護カバーの遅相軸と前記偏光フィルムの吸収軸とのなす角度が－５°～５°または８５°～９５°である。
　１つの実施形態においては、前記保護カバーの遅相軸と前記偏光フィルムの吸収軸とのなす角度が４０°～５０°であり、前記保護カバーの遅相軸と前記高位相差層の遅相軸とのなす角度が、－５°～５°または８５°～９５°である。
　１つの実施形態においては、前記保護カバーの厚みが１０００μｍ以上である。
　１つの実施形態においては、前記保護カバーのＡＳＴＭ－Ｄ７９０の曲げ試験方法による曲げ強さをＳ（ｋｇｆ/ｃｍ２）とし、前記保護カバーの厚みをＴ（ｍｍ）としたとき、Ｓ×Ｔの値が４００以上である。
　１つの実施形態においては、前記保護カバーと前記高位相差層との間に粘着剤が充填されている。
　１つの実施形態においては、前記保護カバーの前記偏光フィルムとは反対側に反射防止フィルムが積層されている。
　本発明の液晶表示装置は、上記光学部材を備えている。 The optical member of the present invention includes a polarizing film, a high retardation layer, and a protective cover in this order, the in-plane retardation of the high retardation layer is 3000 nm to 30000 nm, the slow axis of the high retardation layer, and the polarization The angle formed with the absorption axis of the film is 40 ° to 50 °, and the in-plane retardation of the protective cover is 7000 nm or less.
In one embodiment, the in-plane phase difference of the protective cover is 1000 nm or less.
In one embodiment, an angle formed between the slow axis of the protective cover and the absorption axis of the polarizing film is −5 ° to 5 ° or 85 ° to 95 °.
In one embodiment, the angle formed by the slow axis of the protective cover and the absorption axis of the polarizing film is 40 ° to 50 °, and the slow axis of the protective cover and the slow axis of the high retardation layer Is an angle of −5 ° to 5 ° or 85 ° to 95 °.
In one embodiment, the thickness of the protective cover is 1000 μm or more.
In one embodiment, when the bending strength of the protective cover according to ASTM-D790 bending test method is S (kgf / cm 2 ) and the thickness of the protective cover is T (mm), S × T The value is 400 or more.
In one embodiment, an adhesive is filled between the protective cover and the high retardation layer.
In one embodiment, an antireflection film is laminated on the side of the protective cover opposite to the polarizing film.
The liquid crystal display device of the present invention includes the optical member.
　本発明によれば、偏光サングラスを通して保護カバー付きの液晶表示装置を視認したときの視認性の低下を抑制し得る。 According to the present invention, it is possible to suppress a decrease in visibility when a liquid crystal display device with a protective cover is visually recognized through polarized sunglasses.
本発明の１つの実施形態に係る光学部材の断面図である。It is sectional drawing of the optical member which concerns on one Embodiment of this invention. 本発明の別の実施形態の光学部材の断面図である。It is sectional drawing of the optical member of another embodiment of this invention. 本発明のさらに別の実施形態の光学部材の断面図である。It is sectional drawing of the optical member of another embodiment of this invention.
　以下、本発明の実施形態について説明するが、本発明はこれらの実施形態には限定されない。 Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these embodiments.
（用語および記号の定義）
　本明細書において、「面内位相差」とは、２３℃における波長５５０ｎｍの光で測定した層（フィルム）の面内における位相差であり、層（フィルム）の厚みをｄ（ｎｍ）としたとき、式：Ｒｅ＝（ｎｘ－ｎｙ）×ｄによって求められる。ここで、「ｎｘ」は面内の屈折率が最大になる方向（すなわち、遅相軸方向）の屈折率であり、「ｎｙ」は面内で遅相軸と直交する方向（すなわち、進相軸方向）の屈折率であり、「ｎｚ」は厚み方向の屈折率とする。 (Definition of terms and symbols)
In the present specification, the “in-plane retardation” is an in-plane retardation of a layer (film) measured with light having a wavelength of 550 nm at 23 ° C., and a thickness of the layer (film) is defined as d (nm). Is obtained by the equation: Re = (nx−ny) × d. Here, “nx” is the refractive index in the direction in which the in-plane refractive index is maximum (that is, the slow axis direction), and “ny” is the direction orthogonal to the slow axis in the plane (that is, the fast phase). (Nz direction), and “nz” is the refractive index in the thickness direction.
Ａ．光学部材
　図１は、本発明の１つの実施形態の光学部材の断面図である。図１に示すように、光学部材１０は、偏光フィルム１と高位相差層２と保護カバー３とをこの順に有しており、偏光フィルム１と高位相差層２とが粘着剤４を介して貼り合わされている。高位相差層２の面内位相差は３０００ｎｍ～３００００ｎｍであり、保護カバー３の面内位相差は７０００ｎｍ以下であり、高位相差層２の遅相軸と偏光フィルム１の吸収軸とのなす角度は４０°～５０°である。本発明の光学部材１０は、液晶表示装置に搭載され得る。光学部材１０を液晶表示装置の液晶セルの視認者側に設けることにより、偏光サングラスを通して液晶表示装置の表示画面を観察したときの視認性を向上させることができる。具体的には、正面輝度の低下、および視野角に応じた色相の変化（カラーシフト）を抑制することができる。 A. Optical Member FIG. 1 is a cross-sectional view of an optical member according to one embodiment of the present invention. As shown in FIG. 1, the optical member 10 has a polarizing film 1, a high retardation layer 2, and a protective cover 3 in this order, and the polarizing film 1 and the high retardation layer 2 are attached via an adhesive 4. Are combined. The in-plane retardation of the high retardation layer 2 is 3000 nm to 30000 nm, the in-plane retardation of the protective cover 3 is 7000 nm or less, and the angle formed between the slow axis of the high retardation layer 2 and the absorption axis of the polarizing film 1 is 40 ° to 50 °. The optical member 10 of the present invention can be mounted on a liquid crystal display device. By providing the optical member 10 on the viewer side of the liquid crystal cell of the liquid crystal display device, the visibility when the display screen of the liquid crystal display device is observed through polarized sunglasses can be improved. Specifically, a decrease in front luminance and a change in hue (color shift) according to the viewing angle can be suppressed.
　図２は本発明の別の実施形態の光学部材の断面図である。図２に示す光学部材１１は、高位相差層２と保護カバー３とが、層間充填粘着剤５を介して貼り合わされた構造を有している。図３は本発明のさらに別の実施形態の光学部材の断面図である。図３に示す光学部材１２のように、保護カバー３の視認者側に反射防止フィルム６が設けられていてもよい。反射防止フィルム６としては、当業界で通常用いられている反射防止フィルムを採用することができ、例えば、中屈折率材料からなる層と高屈折率材料からなる層と低屈折率材料からなる層とを有する多層フィルムを採用し得る。 FIG. 2 is a cross-sectional view of an optical member according to another embodiment of the present invention. The optical member 11 shown in FIG. 2 has a structure in which the high retardation layer 2 and the protective cover 3 are bonded together with an interlayer filling adhesive 5 interposed therebetween. FIG. 3 is a cross-sectional view of an optical member according to still another embodiment of the present invention. As in the optical member 12 shown in FIG. 3, the antireflection film 6 may be provided on the viewer side of the protective cover 3. As the antireflection film 6, an antireflection film usually used in the industry can be employed. For example, a layer made of a medium refractive index material, a layer made of a high refractive index material, and a layer made of a low refractive index material. Can be employed.
Ｂ．偏光フィルム
　偏光フィルム１は、偏光子と保護層との積層構造を有している。具体的には、偏光フィルム１と高位相差層２と保護カバー３との積層構造において、偏光子の保護カバー３側に保護層（図示せず）が設けられ得る。また、偏光子の保護カバー３とは反対側に別の保護層（図示せず：以下、内側保護層とも称する）を備えてもよい。 B. Polarizing film The polarizing film 1 has a laminated structure of a polarizer and a protective layer. Specifically, in the laminated structure of the polarizing film 1, the high retardation layer 2, and the protective cover 3, a protective layer (not shown) may be provided on the protective cover 3 side of the polarizer. Further, another protective layer (not shown: hereinafter also referred to as an inner protective layer) may be provided on the opposite side of the polarizer from the protective cover 3.
Ｂ－１．偏光子
　偏光子としては、任意の適切な偏光子が採用され得る。例えば、偏光子を形成する樹脂フィルムは、単層の樹脂フィルムであってもよく、二層以上の積層体であってもよい。 B-1. Polarizer Any appropriate polarizer may be adopted as the polarizer. For example, the resin film forming the polarizer may be a single-layer resin film or a laminate of two or more layers.
　単層の樹脂フィルムから構成される偏光子の具体例としては、ポリビニルアルコール（ＰＶＡ）系フィルム、部分ホルマール化ＰＶＡ系フィルム、エチレン・酢酸ビニル共重合体系部分ケン化フィルム等の親水性高分子フィルムに、ヨウ素や二色性染料等の二色性物質による染色処理および延伸処理が施されたもの、ＰＶＡの脱水処理物やポリ塩化ビニルの脱塩酸処理物等ポリエン系配向フィルム等が挙げられる。好ましくは、光学特性に優れることから、ＰＶＡ系フィルムをヨウ素で染色し一軸延伸して得られた偏光子が用いられる。 Specific examples of polarizers composed of a single-layer resin film include hydrophilic polymer films such as polyvinyl alcohol (PVA) films, partially formalized PVA films, and ethylene / vinyl acetate copolymer partially saponified films. In addition, there may be mentioned polyene-based oriented films such as those subjected to dyeing treatment and stretching treatment with dichroic substances such as iodine and dichroic dyes, PVA dehydrated products and polyvinyl chloride dehydrochlorinated products. Preferably, a polarizer obtained by dyeing a PVA film with iodine and uniaxially stretching is used because of excellent optical properties.
　上記ヨウ素による染色は、例えば、ＰＶＡ系フィルムをヨウ素水溶液に浸漬することにより行われる。上記一軸延伸の延伸倍率は、好ましくは３～７倍である。延伸は、染色処理後に行ってもよいし、染色しながら行ってもよい。また、延伸してから染色してもよい。必要に応じて、ＰＶＡ系フィルムに、膨潤処理、架橋処理、洗浄処理、乾燥処理等が施される。例えば、染色の前にＰＶＡ系フィルムを水に浸漬して水洗することで、ＰＶＡ系フィルム表面の汚れやブロッキング防止剤を洗浄することができるだけでなく、ＰＶＡ系フィルムを膨潤させて染色ムラなどを防止することができる。 The dyeing with iodine is performed, for example, by immersing a PVA film in an aqueous iodine solution. The stretching ratio of the uniaxial stretching is preferably 3 to 7 times. The stretching may be performed after the dyeing treatment or may be performed while dyeing. Moreover, you may dye | stain after extending | stretching. If necessary, the PVA film is subjected to swelling treatment, crosslinking treatment, washing treatment, drying treatment and the like. For example, by immersing the PVA film in water and washing it before dyeing, not only can the surface of the PVA film be cleaned of dirt and anti-blocking agents, but the PVA film can be swollen to cause uneven staining. Can be prevented.
　積層体を用いて得られる偏光子の具体例としては、樹脂基材と当該樹脂基材に積層されたＰＶＡ系樹脂層（ＰＶＡ系樹脂フィルム）との積層体、あるいは、樹脂基材と当該樹脂基材に塗布形成されたＰＶＡ系樹脂層との積層体を用いて得られる偏光子が挙げられる。樹脂基材と当該樹脂基材に塗布形成されたＰＶＡ系樹脂層との積層体を用いて得られる偏光子は、例えば、ＰＶＡ系樹脂溶液を樹脂基材に塗布し、乾燥させて樹脂基材上にＰＶＡ系樹脂層を形成して、樹脂基材とＰＶＡ系樹脂層との積層体を得ること；当該積層体を延伸および染色してＰＶＡ系樹脂層を偏光子とすること；により作製され得る。本実施形態においては、延伸は、代表的には積層体をホウ酸水溶液中に浸漬させて延伸することを含む。さらに、延伸は、必要に応じて、ホウ酸水溶液中での延伸の前に積層体を高温（例えば、９５℃以上）で空中延伸することをさらに含み得る。得られた樹脂基材／偏光子の積層体はそのまま用いてもよく（すなわち、樹脂基材を偏光子の保護層としてもよく）、樹脂基材／偏光子の積層体から樹脂基材を剥離し、当該剥離面に目的に応じた任意の適切な保護層を積層して用いてもよい。このような偏光子の製造方法の詳細は、例えば特開２０１２－７３５８０号公報に記載されている。当該公報は、その全体の記載が本明細書に参考として援用される。 As a specific example of a polarizer obtained by using a laminate, a laminate of a resin substrate and a PVA resin layer (PVA resin film) laminated on the resin substrate, or a resin substrate and the resin Examples thereof include a polarizer obtained by using a laminate with a PVA resin layer applied and formed on a substrate. For example, a polarizer obtained by using a laminate of a resin base material and a PVA resin layer applied and formed on the resin base material may be obtained by, for example, applying a PVA resin solution to a resin base material and drying it. A PVA-based resin layer is formed thereon to obtain a laminate of a resin base material and a PVA-based resin layer; the laminate is stretched and dyed to make the PVA-based resin layer a polarizer; obtain. In the present embodiment, stretching typically includes immersing the laminate in an aqueous boric acid solution and stretching. Furthermore, the stretching may further include, if necessary, stretching the laminate in the air at a high temperature (for example, 95 ° C. or higher) before stretching in the aqueous boric acid solution. The obtained resin base material / polarizer laminate may be used as it is (that is, the resin base material may be used as a protective layer of the polarizer), and the resin base material is peeled from the resin base material / polarizer laminate. Any appropriate protective layer according to the purpose may be laminated on the release surface. Details of a method for manufacturing such a polarizer are described in, for example, Japanese Patent Application Laid-Open No. 2012-73580. This publication is incorporated herein by reference in its entirety.
　偏光子の厚みは、代表的には１μｍ～８０μｍである。偏光子の厚みの上限は、好ましくは５０μｍであり、より好ましくは３５μｍであり、特に好ましくは３０μｍである。偏光子の厚みの下限は、好ましくは１μｍであり、より好ましくは３μｍである。偏光子の厚みがこのような範囲であれば、加熱時のカールを良好に抑制することができ、および、良好な加熱時の外観耐久性が得られる。 The thickness of the polarizer is typically 1 μm to 80 μm. The upper limit of the thickness of the polarizer is preferably 50 μm, more preferably 35 μm, and particularly preferably 30 μm. The lower limit of the thickness of the polarizer is preferably 1 μm, more preferably 3 μm. When the thickness of the polarizer is in such a range, curling during heating can be satisfactorily suppressed, and good appearance durability during heating can be obtained.
Ｂ－２．保護層
　上記保護層は、偏光子の保護層として使用できる任意の適切なフィルムで形成される。当該フィルムの主成分となる材料の具体例としては、トリアセチルセルロース（ＴＡＣ）等のセルロース系樹脂や、ポリエステル系、ポリビニルアルコール系、ポリカーボネート系、ポリアミド系、ポリイミド系、ポリエーテルスルホン系、ポリスルホン系、ポリスチレン系、ポリノルボルネン系、ポリオレフィン系、（メタ）アクリル系、アセテート系等の透明樹脂等が挙げられる。また、（メタ）アクリル系、ウレタン系、（メタ）アクリルウレタン系、エポキシ系、シリコーン系等の熱硬化型樹脂または紫外線硬化型樹脂等も挙げられる。この他にも、例えば、シロキサン系ポリマー等のガラス質系ポリマーも挙げられる。また、特開２００１－３４３５２９号公報（ＷＯ０１／３７００７）に記載のポリマーフィルムも使用できる。このフィルムの材料としては、例えば、側鎖に置換または非置換のイミド基を有する熱可塑性樹脂と、側鎖に置換または非置換のフェニル基ならびにニトリル基を有する熱可塑性樹脂を含有する樹脂組成物が使用でき、例えば、イソブテンとＮ－メチルマレイミドからなる交互共重合体と、アクリロニトリル・スチレン共重合体とを有する樹脂組成物が挙げられる。当該ポリマーフィルムは、例えば、上記樹脂組成物の押出成形物であり得る。 B-2. Protective layer The protective layer is formed of any suitable film that can be used as a protective layer for a polarizer. Specific examples of the material as the main component of the film include cellulose resins such as triacetyl cellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyethersulfone-based, and polysulfone-based materials. And transparent resins such as polystyrene, polynorbornene, polyolefin, (meth) acryl, and acetate. Further, thermosetting resins such as (meth) acrylic, urethane-based, (meth) acrylurethane-based, epoxy-based, and silicone-based or ultraviolet curable resins are also included. In addition to this, for example, a glassy polymer such as a siloxane polymer is also included. Further, a polymer film described in JP-A-2001-343529 (WO01 / 37007) can also be used. As a material for this film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in the side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and nitrile group in the side chain For example, a resin composition having an alternating copolymer of isobutene and N-methylmaleimide and an acrylonitrile / styrene copolymer can be mentioned. The polymer film can be, for example, an extruded product of the resin composition.
　保護層には、必要に応じて、ハードコート処理、反射防止処理、スティッキング防止処理、アンチグレア処理等の表面処理が施されていてもよい。さらに／あるいは、保護層には、必要に応じて、偏光サングラスを介して視認する場合の視認性を改善する処理（代表的には、（楕）円偏光機能を付与すること、超高位相差を付与すること）が施されていてもよい。このような処理を施すことにより、光学部材１０を搭載した液晶表示装置の表示画面を、偏光サングラスを介して視認したときの視認性を向上させることができる。 The protective layer may be subjected to surface treatment such as hard coat treatment, antireflection treatment, anti-sticking treatment, and antiglare treatment as necessary. Further / or, if necessary, the protective layer may be treated to improve visibility when viewed through polarized sunglasses (typically, an (elliptical) circular polarization function is added, an ultra-high phase difference is applied. Granting). By performing such processing, it is possible to improve the visibility when the display screen of the liquid crystal display device on which the optical member 10 is mounted is viewed through the polarized sunglasses.
　保護層の厚みは、代表的には５ｍｍ以下であり、好ましくは１ｍｍ以下、より好ましくは１μｍ～５００μｍ、さらに好ましくは５μｍ～１５０μｍである。なお、表面処理が施されている場合、保護層の厚みは、表面処理層の厚みを含めた厚みである。 The thickness of the protective layer is typically 5 mm or less, preferably 1 mm or less, more preferably 1 μm to 500 μm, and even more preferably 5 μm to 150 μm. In addition, when the surface treatment is performed, the thickness of the protective layer is a thickness including the thickness of the surface treatment layer.
　内側保護層は、光学的に等方性であることが好ましい。本明細書において「光学的に等方性である」とは、面内位相差Ｒｅ（５５０）が０ｎｍ～１０ｎｍであり、厚み方向の位相差Ｒｔｈ（５５０）が－１０ｎｍ～＋１０ｎｍであることをいう。内側保護層は、光学的に等方性である限り、任意の適切な材料で構成され得る。当該材料は、例えば、保護層に関して上記した材料から適切に選択され得る。 The inner protective layer is preferably optically isotropic. In this specification, “optically isotropic” means that the in-plane retardation Re (550) is 0 nm to 10 nm and the thickness direction retardation Rth (550) is −10 nm to +10 nm. Say. The inner protective layer can be composed of any suitable material as long as it is optically isotropic. The material can be appropriately selected from the materials described above with respect to the protective layer, for example.
　内側保護層の厚みは、好ましくは５μｍ～２００μｍ、より好ましくは１０μｍ～１００μｍ、さらに好ましくは１５μｍ～９５μｍである。 The thickness of the inner protective layer is preferably 5 μm to 200 μm, more preferably 10 μm to 100 μm, and still more preferably 15 μm to 95 μm.
Ｃ．粘着剤
　粘着剤４としては、任意の適切な粘着剤が採用され得る。粘着剤４は、代表的にはアクリル系粘着剤で形成される。 C. Adhesive As the adhesive 4, any appropriate adhesive can be adopted. The pressure-sensitive adhesive 4 is typically formed of an acrylic pressure-sensitive adhesive.
Ｄ．高位相差層
　高位相差層２は、複屈折性を有する透明材料からなる。高位相差層２の面内位相差は、３０００ｎｍ以上３００００ｎｍ以下であり、より好ましくは１００００ｎｍ以上である。また、高位相差層２の厚みは任意であり、好ましくは２５μｍ～５００μｍであり、より好ましくは３５μｍ～３５０μｍである。高位相差層２の遅相軸と偏光フィルム１の吸収軸とのなす角度は、好ましくは４０°～５０°であり、より好ましくは４２°～４８°であり、特に好ましくは約４５°である。上記高位相差層２を備えた光学部材１０を液晶表示装置に設けることによって、偏光サングラスを通して液晶表示装置を視認した場合の輝度低下および虹ムラを抑制することができる。 D. High retardation layer The high retardation layer 2 is made of a transparent material having birefringence. The in-plane retardation of the high retardation layer 2 is 3000 nm or more and 30000 nm or less, and more preferably 10,000 nm or more. The thickness of the high retardation layer 2 is arbitrary, preferably 25 μm to 500 μm, and more preferably 35 μm to 350 μm. The angle formed by the slow axis of the high retardation layer 2 and the absorption axis of the polarizing film 1 is preferably 40 ° to 50 °, more preferably 42 ° to 48 °, and particularly preferably about 45 °. . By providing the optical member 10 including the high retardation layer 2 in the liquid crystal display device, it is possible to suppress a decrease in luminance and rainbow unevenness when the liquid crystal display device is viewed through polarized sunglasses.
　高位相差層２は、任意の適切な材料から形成され得る。上記材料として、ポリエチレンテレフタレートやポリエチレンナフタレート等のポリエステル、ポリカーボネート、ポリスチレン、ポリエーテルエーテルケトン、ポリフェニレンサルファイド、シクロオレフィンポリマーが挙げられる。特に、ポリエチレンテレフタレートに代表されるポリエステルは固有複屈折が大きく、厚みが薄くても比較的容易に大きな面内位相差が得られることから、好適に用いることができる。 The high retardation layer 2 can be formed of any appropriate material. Examples of the material include polyesters such as polyethylene terephthalate and polyethylene naphthalate, polycarbonate, polystyrene, polyether ether ketone, polyphenylene sulfide, and cycloolefin polymer. In particular, polyesters typified by polyethylene terephthalate have a large intrinsic birefringence and can be suitably used because a large in-plane retardation can be obtained relatively easily even when the thickness is small.
Ｅ．保護カバー
　保護カバー３は、複屈折性を有する透明なプラスチック材料からなる。保護カバー３の面内位相差は７０００ｎｍ以下である。保護カバー３の面内位相差の上限は、好ましくは５０００ｎｍであり、より好ましくは３０００ｎｍであり、特に好ましくは１０００ｎｍである。保護カバー３の面内位相差は０ｎｍより大きい。これにより、偏光サングラスを通して上記保護カバー３を搭載した液晶表示装置を視認する場合において、高位相差層２を設けることによるカラーシフトの発生を抑制することができる。 E. Protective cover The protective cover 3 is made of a transparent plastic material having birefringence. The in-plane retardation of the protective cover 3 is 7000 nm or less. The upper limit of the in-plane retardation of the protective cover 3 is preferably 5000 nm, more preferably 3000 nm, and particularly preferably 1000 nm. The in-plane retardation of the protective cover 3 is greater than 0 nm. Thereby, when visually recognizing the liquid crystal display device on which the protective cover 3 is mounted through the polarized sunglasses, it is possible to suppress the occurrence of color shift due to the provision of the high retardation layer 2.
　保護カバー３の遅相軸と偏光フィルム１の吸収軸とのなす角度は特に限定されない。保護カバー３の遅相軸と偏光フィルム１の吸収軸とのなす角度は、代表的には、実質的に０°、実質的に４５°、または実質的に９０°である。具体的には、保護カバー３の遅相軸と偏光フィルム１の吸収軸とのなす角度は好ましくは－５°～５°、４０°～５０°、または８５°～９５°であり、より好ましくは－３°～３°、４２°～４８°、または８７°～９３°であり、特に好ましくは約０°、約４５°、または約９０°である。 The angle formed between the slow axis of the protective cover 3 and the absorption axis of the polarizing film 1 is not particularly limited. The angle formed by the slow axis of the protective cover 3 and the absorption axis of the polarizing film 1 is typically substantially 0 °, substantially 45 °, or substantially 90 °. Specifically, the angle formed by the slow axis of the protective cover 3 and the absorption axis of the polarizing film 1 is preferably −5 ° to 5 °, 40 ° to 50 °, or 85 ° to 95 °, more preferably. Is from -3 ° to 3 °, from 42 ° to 48 °, or from 87 ° to 93 °, particularly preferably about 0 °, about 45 °, or about 90 °.
　保護カバー３の遅相軸と偏光フィルム１の吸収軸とのなす角度が実質的に４５°である場合、保護カバー３の遅相軸と高位相差層２の遅相軸とのなす角度は実質的に０°または実質的に９０°である。具体的には、保護カバー３の遅相軸と偏光フィルム１の吸収軸とのなす角度は好ましくは－５°～５°または８５°～９５°であり、より好ましくは－３°～３°または８７°～９３°であり、特に好ましくは約０°または約９０°である。 When the angle formed between the slow axis of the protective cover 3 and the absorption axis of the polarizing film 1 is substantially 45 °, the angle formed between the slow axis of the protective cover 3 and the slow axis of the high retardation layer 2 is substantially 0 ° or substantially 90 °. Specifically, the angle formed by the slow axis of the protective cover 3 and the absorption axis of the polarizing film 1 is preferably −5 ° to 5 ° or 85 ° to 95 °, more preferably −3 ° to 3 °. Or from 87 ° to 93 °, particularly preferably about 0 ° or about 90 °.
　保護カバー３の厚みは、好ましくは１０００μｍ以上であり、より好ましくは２０００μｍ以上である。保護カバー３の厚みを１０００μｍ以上とすることにより、光学部材１０を液晶表示装置の液晶セルの視認者側に設けたときに、液晶セルを保護するために必要な機械的強度を実現することができる。また、保護カバー３の厚みは、４０００μｍ以下であることが好ましい。これにより、液晶表示装置をコンパクト化することができるとともに、タッチパネル付きの液晶表示装置にも保護カバー３を適用することができる。 The thickness of the protective cover 3 is preferably 1000 μm or more, more preferably 2000 μm or more. By setting the thickness of the protective cover 3 to 1000 μm or more, the mechanical strength necessary for protecting the liquid crystal cell can be realized when the optical member 10 is provided on the viewer side of the liquid crystal cell of the liquid crystal display device. it can. Moreover, it is preferable that the thickness of the protective cover 3 is 4000 micrometers or less. Thereby, the liquid crystal display device can be made compact, and the protective cover 3 can be applied to a liquid crystal display device with a touch panel.
　保護カバーの曲げ強さをＳ（ｋｇｆ/ｃｍ２）とし、保護カバーの厚みをＴ（ｍｍ）としたとき、保護カバーの強度を示すＳ×Ｔの値は、好ましくは４００以上であり、より好ましくは５００以上であり、さらに好ましくは６００以上である。一方で、Ｓ×Ｔの上限値は、好ましくは４０００であり、より好ましくは２０００である。保護カバーの曲げ強さは、ＡＳＴＭ－Ｄ７９０の曲げ試験方法に準じて測定することができる。 When the bending strength of the protective cover is S (kgf / cm 2 ) and the thickness of the protective cover is T (mm), the value of S × T indicating the strength of the protective cover is preferably 400 or more. Preferably it is 500 or more, More preferably, it is 600 or more. On the other hand, the upper limit value of S × T is preferably 4000, and more preferably 2000. The bending strength of the protective cover can be measured according to the bending test method of ASTM-D790.
　保護カバー３を構成する材料としては、任意の適切な材料を採用し得る。上記材料として、ポリカーボネート樹脂、ポリメタクリル酸メチル樹脂などを用いることができる。保護カバー３は、図１に示すように隙間を空けることなく偏光フィルム１に貼り合わされていてもよいし、偏光フィルム１との間に隙間を空けて設けられていてもよい。 Any appropriate material can be adopted as the material constituting the protective cover 3. As the material, polycarbonate resin, polymethyl methacrylate resin, or the like can be used. As shown in FIG. 1, the protective cover 3 may be bonded to the polarizing film 1 without leaving a gap, or may be provided with a gap between the protective cover 3 and the polarizing film 1.
　１つの実施形態においては、高位相差層２の面内位相差は３０００ｎｍ～３００００ｎｍであり、高位相差層２の遅相軸と偏光フィルム１の吸収軸とのなす角度は４０°～５０°であり、かつ、保護カバー３の面内位相差は７０００ｎｍ以下である。これにより、光学部材１０を液晶表示装置の液晶セルの視認者側に設けることによって、偏光サングラスを通して液晶表示装置を視認した場合の視認性の低下を抑制することができる。具体的には、正面輝度の低下、および視野角に応じた色相の変化（カラーシフト）を抑制することができる。 In one embodiment, the in-plane retardation of the high retardation layer 2 is 3000 nm to 30000 nm, and the angle formed by the slow axis of the high retardation layer 2 and the absorption axis of the polarizing film 1 is 40 ° to 50 °. And the in-plane phase difference of the protective cover 3 is 7000 nm or less. Thereby, by providing the optical member 10 on the viewer side of the liquid crystal cell of the liquid crystal display device, it is possible to suppress a decrease in visibility when the liquid crystal display device is viewed through the polarized sunglasses. Specifically, a decrease in front luminance and a change in hue (color shift) according to the viewing angle can be suppressed.
Ｆ．層間充填粘着剤
　層間充填粘着剤５として、任意の適切な粘着剤を採用し得る。例えば、層間充填粘着剤５は、アクリル系ポリマーを含むアクリル系粘着剤であってもよい。層間充填粘着剤５におけるアクリル系ポリマーの含有量は、特に限定されないが、臭気の観点から、好ましくは９６重量％～１００重量％、より好ましくは９８重量％～１００重量％である。上記アクリル系ポリマーは、好ましくは、直鎖又は分岐鎖状のアルキル基を有する（メタ）アクリル酸アルキルエステル及び／又は（メタ）アクリル酸アルコキシアルキルエステルを必須のモノマー成分（単量体成分）として構成されたアクリル系ポリマーである。 F. Interlayer Filling Adhesive Any suitable adhesive can be adopted as the interlayer filling adhesive 5. For example, the interlayer filling pressure-sensitive adhesive 5 may be an acrylic pressure-sensitive adhesive containing an acrylic polymer. The content of the acrylic polymer in the interlayer filling adhesive 5 is not particularly limited, but is preferably 96% to 100% by weight, more preferably 98% to 100% by weight from the viewpoint of odor. The acrylic polymer preferably has (meth) acrylic acid alkyl ester and / or (meth) acrylic acid alkoxyalkyl ester having a linear or branched alkyl group as an essential monomer component (monomer component). It is a structured acrylic polymer.
　層間充填粘着剤５の具体的構成としては、好ましくは、アクリル系ポリマーを構成するモノマー成分全量（１００重量％）に対して、アクリル酸２－エチルヘキシル（２ＥＨＡ）を８４～９４重量％、アクリル酸（ＡＡ）を５～１５重量％、ジペンタエリスリトールヘキサアクリレート（ＤＰＨＡ）を０．０３～０．１５重量％含有するモノマー成分から構成されたアクリル系ポリマーを含むアクリル系粘着剤層である。また、層間充填粘着剤５の他の具体的構成としては、好ましくは、アクリル系ポリマーを構成するモノマー成分全量（１００重量％）に対して、アクリル酸イソオクチル（ｉ－ＯＡ）８４～９４重量％、アクリル酸（ＡＡ）５～１５重量％、ジペンタエリスリトールヘキサアクリレート（ＤＰＨＡ）を０．０３～０．１５重量％含有するモノマー成分から構成されたアクリル系ポリマーを含むアクリル系粘着剤層である。 The specific constitution of the interlayer filling pressure-sensitive adhesive 5 is preferably 84 to 94% by weight of 2-ethylhexyl acrylate (2EHA), acrylic acid based on the total amount (100% by weight) of monomer components constituting the acrylic polymer. This is an acrylic pressure-sensitive adhesive layer containing an acrylic polymer composed of a monomer component containing 5 to 15% by weight of (AA) and 0.03 to 0.15% by weight of dipentaerythritol hexaacrylate (DPHA). Further, as another specific constitution of the interlayer filling pressure-sensitive adhesive 5, preferably, 84 to 94% by weight of isooctyl acrylate (i-OA) with respect to the total amount (100% by weight) of monomer components constituting the acrylic polymer. An acrylic pressure-sensitive adhesive layer containing an acrylic polymer composed of a monomer component containing 5 to 15% by weight of acrylic acid (AA) and 0.03 to 0.15% by weight of dipentaerythritol hexaacrylate (DPHA) .
　層間充填粘着剤５の厚みは、好ましくは２５μｍ～５００μｍであり、より好ましくは７５μｍ～３５０μｍである。層間充填粘着剤５の、保護カバー３に対する２３℃における１８０°引き剥がし粘着力（「粘着力（２３℃）」と称する）は、好ましくは５Ｎ／２０ｍｍ以上であり、より好ましくは８Ｎ／２０ｍｍ以上である。粘着力（２３℃）を５Ｎ／２０ｍｍ以上とすることにより、ディレイバブル（保護カバーとの界面に経時的に表れる気泡）の発生が抑制される。なお、上記粘着力（２３℃）は、２３℃において、保護カバーを被着体とする１８０°剥離試験（ＪＩＳ　Ｚ０２３７（２０００）に準拠、引張速度：３００ｍｍ／分）を行うことにより測定することができる。 The thickness of the interlayer filling adhesive 5 is preferably 25 μm to 500 μm, more preferably 75 μm to 350 μm. The 180 ° peeling adhesive strength (referred to as “adhesive strength (23 ° C.)”) at 23 ° C. of the interlayer filling adhesive 5 at 23 ° C. is preferably 5 N / 20 mm or more, more preferably 8 N / 20 mm or more. It is. By setting the adhesive force (23 ° C.) to 5 N / 20 mm or more, generation of delay bubbles (bubbles appearing at the interface with the protective cover) is suppressed. The adhesive strength (23 ° C.) is measured by performing a 180 ° peel test (according to JIS Z0237 (2000), tensile speed: 300 mm / min) using a protective cover as an adherend at 23 ° C. Can do.
　このような層間充填粘着剤の詳細は、例えば特開２０１２－１５３７８８号公報に粘着剤層として記載されている。当該公報は、その全体の記載が本明細書に参考として援用される。 Details of such an interlayer filling pressure-sensitive adhesive are described as a pressure-sensitive adhesive layer in, for example, Japanese Patent Application Laid-Open No. 2012-153788. This publication is incorporated herein by reference in its entirety.
Ｇ．液晶表示装置
　上記Ａ項からＦ項に記載の光学部材は、液晶表示装置に適用され得る。したがって、本発明は、そのような光学部材を用いた液晶表示装置を包含する。本発明の実施形態による液晶表示装置は、液晶セルと、該液晶セルの視認側に配置された上記Ａ項からＦ項に記載の光学部材を備える。光学部材は、偏光フィルムが液晶セル側となるように配置されている。 G. Liquid Crystal Display Device The optical members described in the items A to F can be applied to a liquid crystal display device. Therefore, the present invention includes a liquid crystal display device using such an optical member. A liquid crystal display device according to an embodiment of the present invention includes a liquid crystal cell and the optical member according to any of items A to F arranged on the viewing side of the liquid crystal cell. The optical member is disposed so that the polarizing film is on the liquid crystal cell side.
　以下、実施例によって本発明を具体的に説明するが、本発明はこれら実施例によって限定されるものではない。 Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples.
　＜実施例１＞
１．偏光板の作製
　厚さ８０μｍのポリビニルアルコールフィルムを、速度比の異なるロール間において、３０℃、０．３％濃度のヨウ素溶液中で１分間染色しながら、３倍まで延伸した。その後、６０℃、４％濃度のホウ酸、１０％濃度のヨウ化カリウムを含む水溶液中に０．５分間浸漬しながら総合延伸倍率が６倍まで延伸した。次いで、３０℃、１．５％濃度のヨウ化カリウムを含む水溶液中に１０秒間浸漬することで洗浄した後、５０℃で４分間乾燥を行い偏光子を得た。当該偏光子の両面に、けん化処理した厚さ８０μｍのトリアセチルセルロースフィルムをポリビニルアルコール系接着剤により貼り合せて偏光板（偏光フィルム）を作成した。 <Example 1>
1. Production of Polarizing Plate A polyvinyl alcohol film having a thickness of 80 μm was stretched up to 3 times while being dyed for 1 minute in an iodine solution of 0.3% concentration at 30 ° C. between rolls having different speed ratios. Thereafter, the total draw ratio was stretched to 6 times while being immersed in an aqueous solution containing 60% at 4% concentration of boric acid and 10% concentration of potassium iodide for 0.5 minutes. Next, after washing by immersing in an aqueous solution containing potassium iodide at 30 ° C. and 1.5% concentration for 10 seconds, drying was performed at 50 ° C. for 4 minutes to obtain a polarizer. A polarizing plate (polarizing film) was prepared by bonding a saponified 80 μm thick triacetyl cellulose film on both surfaces of the polarizer with a polyvinyl alcohol adhesive.
２．光学部材の作製
　保護カバーとして、面内位相差が８７７ｎｍであり、ポリカーボネート樹脂からなる厚み１５００μｍのプラスチックカバー（三菱ガス化学社製、製品名「ＮＦ２０００」）を用いた。また、高位相差層として、面内位相差が８４００ｎｍであり、ポリエチレンテレフタラート樹脂からなる厚み８０μｍの高位相差フィルム（東洋紡社製、製品名「コスモシャインＳＲＦ」）を用いた。
　上記高位相差フィルムと上記偏光板とを、アクリル粘着剤を介して、高位相差フィルムの遅相軸と偏光板の吸収軸とのなす角度θが４５°となるように貼り合わせた。さらに、上記高位相差フィルムに対して、上記プラスチックカバーを、層間充填粘着剤（日東電工社製、製品名「ＣＳ９８６４」）を介して、プラスチックカバーの遅相軸と偏光板の吸収軸とのなす角度θが０°となるように貼り合わせることによって光学部材を得た。
　ＡＳＴＭ－Ｄ７９０の曲げ試験方法に準じて測定した上記保護カバーの曲げ強さをＳ（ｋｇｆ/ｃｍ２）とし、保護カバーの厚みをＴ（ｍｍ）としたとき、保護カバーの強度（Ｓ×Ｔ）は１４２５であった。 2. Production of Optical Member As a protective cover, a plastic cover (product name “NF2000”, manufactured by Mitsubishi Gas Chemical Company) having an in-plane retardation of 877 nm and a thickness of 1500 μm made of polycarbonate resin was used. As the high retardation layer, a high retardation film (product name “COSMO SHINE SRF” manufactured by Toyobo Co., Ltd.) having an in-plane retardation of 8400 nm and a thickness of 80 μm made of polyethylene terephthalate resin was used.
The high retardation film and the polarizing plate were bonded together via an acrylic pressure-sensitive adhesive so that the angle θ formed by the slow axis of the high retardation film and the absorption axis of the polarizing plate was 45 °. Furthermore, with respect to the high retardation film, the plastic cover is formed between the slow axis of the plastic cover and the absorption axis of the polarizing plate via an interlayer filling adhesive (product name “CS9864” manufactured by Nitto Denko Corporation). The optical member was obtained by pasting together so that the angle θ was 0 °.
When the bending strength of the protective cover measured according to the bending test method of ASTM-D790 is S (kgf / cm 2 ) and the thickness of the protective cover is T (mm), the strength of the protective cover (S × T ) Was 1425.
　＜実施例２＞
　保護カバーとして、面内位相差が４６１ｎｍであり、ポリカーボネート樹脂からなる厚み２０００μｍのプラスチックカバー（帝人社製、製品名「ＰＣ１１５１」）を用いたこと以外は実施例１と同様にして光学部材を得た。
　ＡＳＴＭ－Ｄ７９０の曲げ試験方法に準じて測定した上記保護カバーの曲げ強さをＳ（ｋｇｆ/ｃｍ２）とし、保護カバーの厚みをＴ（ｍｍ）としたとき、保護カバーの強度（Ｓ×Ｔ）は１９００であった。 <Example 2>
An optical member was obtained in the same manner as in Example 1 except that a plastic cover (product name “PC1151” manufactured by Teijin Ltd.) with a thickness of 2000 μm made of polycarbonate resin was used as the protective cover. It was.
When the bending strength of the protective cover measured according to the bending test method of ASTM-D790 is S (kgf / cm 2 ) and the thickness of the protective cover is T (mm), the strength of the protective cover (S × T ) Was 1900.
　＜実施例３＞
　保護カバーとして、面内位相差が０．４ｎｍであり、ポリメタクリル酸メチル樹脂からなる厚み１５００μｍのプラスチックカバー（三菱レーヨン社製、製品名「ＭＲ２００」）を用いたこと以外は実施例１と同様にして光学部材を得た。
　ＡＳＴＭ－Ｄ７９０の曲げ試験方法に準じて測定した上記保護カバーの曲げ強さをＳ（ｋｇｆ/ｃｍ２）とし、保護カバーの厚みをＴ（ｍｍ）としたとき、保護カバーの強度（Ｓ×Ｔ）は１４２５であった。 <Example 3>
Example 1 except that a plastic cover (product name “MR200” manufactured by Mitsubishi Rayon Co., Ltd.) having a thickness of 1500 μm made of polymethyl methacrylate resin was used as the protective cover. Thus, an optical member was obtained.
When the bending strength of the protective cover measured according to the bending test method of ASTM-D790 is S (kgf / cm 2 ) and the thickness of the protective cover is T (mm), the strength of the protective cover (S × T ) Was 1425.
　＜実施例４＞
　保護カバーとして、面内位相差が１１２．４ｎｍであり、ポリメタクリル酸メチル樹脂／ポリカーボネート樹脂／ポリメタクリル酸メチル樹脂の積層構造からなる厚み１５００μｍのプラスチックカバー（クラレ社製、製品名「ＭＴ３ＬＴＲ」）を用いたこと以外は実施例１と同様にして光学部材を得た。
　ＡＳＴＭ－Ｄ７９０の曲げ試験方法に準じて測定した上記保護カバーの曲げ強さをＳ（ｋｇｆ/ｃｍ２）とし、保護カバーの厚みをＴ（ｍｍ）としたとき、保護カバーの強度（Ｓ×Ｔ）は１４２５であった。 <Example 4>
As a protective cover, an in-plane retardation of 112.4 nm and a plastic cover with a thickness of 1500 μm made of a laminated structure of polymethyl methacrylate resin / polycarbonate resin / polymethyl methacrylate resin (product name “MT3LTR” manufactured by Kuraray Co., Ltd.) An optical member was obtained in the same manner as in Example 1 except that was used.
When the bending strength of the protective cover measured according to the bending test method of ASTM-D790 is S (kgf / cm 2 ) and the thickness of the protective cover is T (mm), the strength of the protective cover (S × T ) Was 1425.
　＜比較例１＞
　保護カバーとして、面内位相差が７６０５ｎｍであり、ポリメタクリル酸メチル樹脂とポリカーボネート樹脂との積層構造からなる厚み１４５０μｍのプラスチックカバー（三菱ガス化学社製、製品名「ＨＭＲ５５１Ｔ」）を用いたこと以外は実施例１と同様にして光学部材を得た。
　ＡＳＴＭ－Ｄ７９０の曲げ試験方法に準じて測定した上記保護カバーの曲げ強さをＳ（ｋｇｆ/ｃｍ２）とし、保護カバーの厚みをＴ（ｍｍ）としたとき、保護カバーの強度（Ｓ×Ｔ）は１３７７であった。 <Comparative Example 1>
Other than using a plastic cover (product name “HMR551T”, manufactured by Mitsubishi Gas Chemical Co., Inc.) having a thickness of 1450 μm and having a laminated structure of polymethyl methacrylate resin and polycarbonate resin as an in-plane retardation of 7605 nm. Obtained an optical member in the same manner as in Example 1.
When the bending strength of the protective cover measured according to the bending test method of ASTM-D790 is S (kgf / cm 2 ) and the thickness of the protective cover is T (mm), the strength of the protective cover (S × T ) Was 1377.
　＜比較例２＞
　高位相差フィルムおよび粘着剤を用いず、偏光板とプラスチックカバーとを層間充填粘着剤を介して貼り合わせたこと以外は、実施例１と同様にして光学部材を得た。 <Comparative example 2>
An optical member was obtained in the same manner as in Example 1 except that the polarizing plate and the plastic cover were bonded together via an interlayer filling adhesive without using the high retardation film and the adhesive.
　＜比較例３＞
　高位相差フィルムおよび粘着剤を用いず、偏光板とプラスチックカバーとを層間充填粘着剤を介して貼り合わせたこと以外は、実施例２と同様にして光学部材を得た。 <Comparative Example 3>
An optical member was obtained in the same manner as in Example 2, except that the high retardation film and the adhesive were not used, and the polarizing plate and the plastic cover were bonded together via an interlayer filling adhesive.
　＜比較例４＞
　高位相差フィルムおよび粘着剤を用いず、偏光板とプラスチックカバーとを層間充填粘着剤を介して貼り合わせたこと以外は、実施例３と同様にして光学部材を得た。 <Comparative example 4>
An optical member was obtained in the same manner as in Example 3 except that the polarizing plate and the plastic cover were bonded together with an interlayer filling adhesive without using the high retardation film and the adhesive.
　＜比較例５＞
　高位相差フィルムおよび粘着剤を用いず、偏光板とプラスチックカバーとを層間充填粘着剤を介して貼り合わせたこと以外は、実施例４と同様にして光学部材を得た。 <Comparative Example 5>
An optical member was obtained in the same manner as in Example 4 except that the polarizing plate and the plastic cover were bonded together via an interlayer filling adhesive without using the high retardation film and the adhesive.
　＜比較例６＞
　高位相差フィルムおよび粘着剤を用いず、偏光板とプラスチックカバーとを層間充填粘着剤を介して貼り合わせたこと以外は、比較例１と同様にして光学部材を得た。 <Comparative Example 6>
An optical member was obtained in the same manner as in Comparative Example 1, except that the high retardation film and the adhesive were not used, and the polarizing plate and the plastic cover were bonded together via an interlayer filling adhesive.
　実施例１～４および比較例１～６の光学部材について、各光学部材を備える液晶表示装置を、偏光サングラスを通して観察したときの正面輝度およびカラーシフトを、以下のようにして評価した。 For the optical members of Examples 1 to 4 and Comparative Examples 1 to 6, the front luminance and the color shift when the liquid crystal display device including each optical member was observed through polarized sunglasses were evaluated as follows.
（１）正面輝度の測定方法
　アイテック社ＬＥＤ面光源「ＬＰＤＣ１－１２１５０ＮＣＷ－１Ｒ６」を光学部材の背面側（偏光板側）に配置し、偏光サングラスを想定した偏光板を光学部材の前面側（プラスチックカバー側）に配置し、コノスコープ（AUTRONIC　MELCHERS株式会社製）を用いて、光学部材および偏光板を介して光源の輝度を測定した（単位：ｃｄ／ｍ２）。なお、偏光板は、その偏光子の吸収軸が、光学部材の偏光子の吸収軸と直交するように配置した。
（２）カラーシフトの測定方法
　正面輝度の測定と同様にして光源、光学部材、および偏光板を配置し、コノスコープ（AUTRONIC　MELCHERS株式会社製）を用いて、極角０°～６０°方向における方位角０°～３６０°の色相、ｘ値およびｙ値を測定した。カラーシフト量（Δｘｙ値）として、任意の２点におけるｘ値およびｙ値を（ｘＡ，ｙＡ）および（ｘＢ，ｙＢ）として、次式：{（ｘＡ－ｘＢ）２＋（ｙＡ－ｙＢ）２}１／２の最大値をΔｘｙ値とした。なお、偏光板は、その偏光子の吸収軸と光学部材の偏光子の吸収軸とのなす角度が４５°となるように配置した。 (1) Front luminance measurement method An LED surface light source “LPDC1-12150NCW-1R6” manufactured by ITEC Co., Ltd. is placed on the back side (polarizing plate side) of the optical member, and the polarizing plate assuming polarizing sunglasses is placed on the front side of the optical member (plastic The brightness of the light source was measured through the optical member and the polarizing plate using a conoscope (manufactured by AUTRONIC MELCHERS Co., Ltd.) (unit: cd / m 2 ). In addition, the polarizing plate was arrange | positioned so that the absorption axis of the polarizer might be orthogonal to the absorption axis of the polarizer of an optical member.
(2) Color shift measurement method A light source, an optical member, and a polarizing plate are arranged in the same manner as the measurement of front luminance, and a conoscope (manufactured by AUTRONIC MELCHERS Co., Ltd.) is used in a polar angle of 0 ° to 60 ° Hue, x value, and y value at azimuth angles of 0 ° to 360 ° were measured. As the color shift amount (Δxy value), the x value and y value at two arbitrary points are (x A , y A ) and (x B , y B ), and the following formula: {(x A −x B ) 2 + The maximum value of (y A -y B ) 2 } 1/2 was taken as the Δxy value. The polarizing plate was arranged so that the angle formed by the absorption axis of the polarizer and the absorption axis of the polarizer of the optical member was 45 °.
　実施例１～４および比較例１の光学部材の正面輝度およびカラーシフトの測定結果を表１に、比較例２～６の光学部材の正面輝度およびカラーシフトの測定結果を表２に示す。なお、表１および表２には、カラーシフトの測定結果として、ｘｙ色度図（横軸：ｘ値、縦軸：ｙ値）と、カラーシフト量（Δｘｙ値）とを示す。 Table 1 shows the measurement results of the front luminance and color shift of the optical members of Examples 1 to 4 and Comparative Example 1, and Table 2 shows the measurement results of the front luminance and color shift of the optical members of Comparative Examples 2 to 6. Tables 1 and 2 show an xy chromaticity diagram (horizontal axis: x value, vertical axis: y value) and a color shift amount (Δxy value) as measurement results of the color shift.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　本発明の光学部材は、携帯電話、携帯情報端末、デジタルカメラ、ビデオカメラ、携帯ゲーム機、カーナビゲーション、コピー機、プリンター、ファックス、時計、電子レンジ等に搭載される液晶表示装置に好適に用いられる。 The optical member of the present invention is suitably used for a liquid crystal display device mounted on a mobile phone, a portable information terminal, a digital camera, a video camera, a portable game machine, a car navigation system, a copy machine, a printer, a fax machine, a watch, a microwave oven, and the like. It is done.
　１　偏光フィルム
　２　高位相差層
　３　保護カバー
　４　粘着剤
　５　層間充填粘着剤
　６　反射防止フィルム
　１０、１１、１２　光学部材 DESCRIPTION OF SYMBOLS 1 Polarizing film 2 High retardation layer 3 Protective cover 4 Adhesive 5 Interlayer filling adhesive 6 Antireflection film 10, 11, 12 Optical member

Claims (9)

  1. 　偏光フィルムと高位相差層と保護カバーとをこの順に有し、
    　前記高位相差層の面内位相差が３０００ｎｍ～３００００ｎｍであり、
    　前記高位相差層の遅相軸と前記偏光フィルムの吸収軸とのなす角度が４０°～５０°であり、
    　前記保護カバーの面内位相差が７０００ｎｍ以下である、光学部材。     Having a polarizing film, a high retardation layer and a protective cover in this order,
    The in-plane retardation of the high retardation layer is 3000 nm to 30000 nm,
    The angle formed by the slow axis of the high retardation layer and the absorption axis of the polarizing film is 40 ° to 50 °,
    The optical member whose in-plane phase difference of the said protective cover is 7000 nm or less.
  2. 　前記保護カバーの面内位相差が１０００ｎｍ以下である、請求項１に記載の光学部材。 The optical member according to claim 1, wherein an in-plane retardation of the protective cover is 1000 nm or less.
  3. 　前記保護カバーの遅相軸と前記偏光フィルムの吸収軸とのなす角度が－５°～５°または８５°～９５°である、請求項１または２に記載の光学部材。 3. The optical member according to claim 1, wherein an angle formed between a slow axis of the protective cover and an absorption axis of the polarizing film is −5 ° to 5 ° or 85 ° to 95 °.
  4. 　前記保護カバーの遅相軸と前記偏光フィルムの吸収軸とのなす角度が４０°～５０°であり、
    　前記保護カバーの遅相軸と前記高位相差層の遅相軸とのなす角度が、－５°～５°または８５°～９５°である、請求項１または２に記載の光学部材。     The angle formed by the slow axis of the protective cover and the absorption axis of the polarizing film is 40 ° to 50 °,
    The optical member according to claim 1 or 2, wherein an angle formed between the slow axis of the protective cover and the slow axis of the high retardation layer is -5 ° to 5 ° or 85 ° to 95 °.
  5. 　前記保護カバーの厚みが１０００μｍ以上である、請求項１～４の何れか１項に記載の光学部材。 The optical member according to any one of claims 1 to 4, wherein the protective cover has a thickness of 1000 μm or more.
  6. 　前記保護カバーのＡＳＴＭ－Ｄ７９０の曲げ試験方法による曲げ強さをＳ（ｋｇｆ/ｃｍ２）とし、前記保護カバーの厚みをＴ（ｍｍ）としたとき、Ｓ×Ｔの値が４００以上である、請求項１～５の何れか１項に記載の光学部材。 When the bending strength of the protective cover according to ASTM-D790 bending test method is S (kgf / cm 2 ) and the thickness of the protective cover is T (mm), the value of S × T is 400 or more. The optical member according to any one of claims 1 to 5.
  7. 　前記保護カバーと前記高位相差層との間に粘着剤が充填されている、請求項１～６の何れか１項に記載の光学部材。 The optical member according to any one of claims 1 to 6, wherein an adhesive is filled between the protective cover and the high retardation layer.
  8. 　前記保護カバーの前記偏光フィルムとは反対側に反射防止フィルムが積層されている、請求項１～７の何れか１項に記載の光学部材。 The optical member according to any one of claims 1 to 7, wherein an antireflection film is laminated on a side of the protective cover opposite to the polarizing film.
  9. 　請求項１～８の何れか１項に記載の光学部材を備えた、液晶表示装置。 A liquid crystal display device comprising the optical member according to any one of claims 1 to 8.
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