CN115461659A - Polarizing plate and image display device using the same - Google Patents
Polarizing plate and image display device using the same Download PDFInfo
- Publication number
- CN115461659A CN115461659A CN202180031365.9A CN202180031365A CN115461659A CN 115461659 A CN115461659 A CN 115461659A CN 202180031365 A CN202180031365 A CN 202180031365A CN 115461659 A CN115461659 A CN 115461659A
- Authority
- CN
- China
- Prior art keywords
- stretching
- pva
- polarizing plate
- polarizer
- laminate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 229920005989 resin Polymers 0.000 claims abstract description 132
- 239000011347 resin Substances 0.000 claims abstract description 132
- 239000004372 Polyvinyl alcohol Substances 0.000 claims abstract description 114
- 229920002451 polyvinyl alcohol Polymers 0.000 claims abstract description 114
- 239000011241 protective layer Substances 0.000 claims abstract description 46
- 239000000126 substance Substances 0.000 claims description 5
- 239000000463 material Substances 0.000 abstract description 29
- 238000003384 imaging method Methods 0.000 abstract description 5
- 239000010408 film Substances 0.000 description 56
- 239000010410 layer Substances 0.000 description 44
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 39
- 239000004327 boric acid Substances 0.000 description 39
- 239000000758 substrate Substances 0.000 description 38
- 229920005992 thermoplastic resin Polymers 0.000 description 36
- 238000010438 heat treatment Methods 0.000 description 28
- 239000000243 solution Substances 0.000 description 28
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 28
- 238000001035 drying Methods 0.000 description 25
- 239000011248 coating agent Substances 0.000 description 21
- 238000000576 coating method Methods 0.000 description 21
- 230000003287 optical effect Effects 0.000 description 21
- NLKNQRATVPKPDG-UHFFFAOYSA-M potassium iodide Chemical compound [K+].[I-] NLKNQRATVPKPDG-UHFFFAOYSA-M 0.000 description 21
- 230000004075 alteration Effects 0.000 description 19
- 238000000034 method Methods 0.000 description 19
- 238000004043 dyeing Methods 0.000 description 17
- 239000007788 liquid Substances 0.000 description 17
- 150000004820 halides Chemical class 0.000 description 15
- ZCYVEMRRCGMTRW-UHFFFAOYSA-N 7553-56-2 Chemical compound [I] ZCYVEMRRCGMTRW-UHFFFAOYSA-N 0.000 description 12
- 229910052740 iodine Inorganic materials 0.000 description 12
- 239000011630 iodine Substances 0.000 description 12
- 239000000853 adhesive Substances 0.000 description 11
- 230000001070 adhesive effect Effects 0.000 description 11
- 238000002425 crystallisation Methods 0.000 description 11
- 230000008025 crystallization Effects 0.000 description 11
- 150000001925 cycloalkenes Chemical class 0.000 description 11
- 238000007654 immersion Methods 0.000 description 11
- 239000007864 aqueous solution Substances 0.000 description 9
- 238000011156 evaluation Methods 0.000 description 9
- 238000005259 measurement Methods 0.000 description 9
- 238000007127 saponification reaction Methods 0.000 description 9
- 238000006243 chemical reaction Methods 0.000 description 8
- 238000004519 manufacturing process Methods 0.000 description 8
- 238000004132 cross linking Methods 0.000 description 7
- 238000006116 polymerization reaction Methods 0.000 description 7
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 6
- 230000009477 glass transition Effects 0.000 description 6
- XMBWDFGMSWQBCA-UHFFFAOYSA-N hydrogen iodide Chemical compound I XMBWDFGMSWQBCA-UHFFFAOYSA-N 0.000 description 6
- 229920005668 polycarbonate resin Polymers 0.000 description 6
- 239000004431 polycarbonate resin Substances 0.000 description 6
- 239000000047 product Substances 0.000 description 6
- 239000004925 Acrylic resin Substances 0.000 description 5
- 229920000178 Acrylic resin Polymers 0.000 description 5
- 239000002904 solvent Substances 0.000 description 5
- 229920000219 Ethylene vinyl alcohol Polymers 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 238000005401 electroluminescence Methods 0.000 description 4
- 230000001678 irradiating effect Effects 0.000 description 4
- 230000003746 surface roughness Effects 0.000 description 4
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 3
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000005038 ethylene vinyl acetate Substances 0.000 description 3
- 238000001125 extrusion Methods 0.000 description 3
- 238000007602 hot air drying Methods 0.000 description 3
- 239000004973 liquid crystal related substance Substances 0.000 description 3
- 239000000178 monomer Substances 0.000 description 3
- 239000008188 pellet Substances 0.000 description 3
- 230000002093 peripheral effect Effects 0.000 description 3
- 229920001200 poly(ethylene-vinyl acetate) Polymers 0.000 description 3
- 229920000642 polymer Polymers 0.000 description 3
- 239000011342 resin composition Substances 0.000 description 3
- FVAUCKIRQBBSSJ-UHFFFAOYSA-M sodium iodide Chemical compound [Na+].[I-] FVAUCKIRQBBSSJ-UHFFFAOYSA-M 0.000 description 3
- 238000003756 stirring Methods 0.000 description 3
- 238000002834 transmittance Methods 0.000 description 3
- -1 trimethylolpropane Chemical class 0.000 description 3
- 238000005406 washing Methods 0.000 description 3
- BTBUEUYNUDRHOZ-UHFFFAOYSA-N Borate Chemical compound [O-]B([O-])[O-] BTBUEUYNUDRHOZ-UHFFFAOYSA-N 0.000 description 2
- 229920002284 Cellulose triacetate Polymers 0.000 description 2
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 description 2
- JOYRKODLDBILNP-UHFFFAOYSA-N Ethyl urethane Chemical compound CCOC(N)=O JOYRKODLDBILNP-UHFFFAOYSA-N 0.000 description 2
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 2
- BAVYZALUXZFZLV-UHFFFAOYSA-N Methylamine Chemical compound NC BAVYZALUXZFZLV-UHFFFAOYSA-N 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 2
- NNLVGZFZQQXQNW-ADJNRHBOSA-N [(2r,3r,4s,5r,6s)-4,5-diacetyloxy-3-[(2s,3r,4s,5r,6r)-3,4,5-triacetyloxy-6-(acetyloxymethyl)oxan-2-yl]oxy-6-[(2r,3r,4s,5r,6s)-4,5,6-triacetyloxy-2-(acetyloxymethyl)oxan-3-yl]oxyoxan-2-yl]methyl acetate Chemical compound O([C@@H]1O[C@@H]([C@H]([C@H](OC(C)=O)[C@H]1OC(C)=O)O[C@H]1[C@@H]([C@@H](OC(C)=O)[C@H](OC(C)=O)[C@@H](COC(C)=O)O1)OC(C)=O)COC(=O)C)[C@@H]1[C@@H](COC(C)=O)O[C@@H](OC(C)=O)[C@H](OC(C)=O)[C@H]1OC(C)=O NNLVGZFZQQXQNW-ADJNRHBOSA-N 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 238000003851 corona treatment Methods 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 238000001879 gelation Methods 0.000 description 2
- LEQAOMBKQFMDFZ-UHFFFAOYSA-N glyoxal Chemical compound O=CC=O LEQAOMBKQFMDFZ-UHFFFAOYSA-N 0.000 description 2
- 238000005286 illumination Methods 0.000 description 2
- 238000007689 inspection Methods 0.000 description 2
- QQVIHTHCMHWDBS-UHFFFAOYSA-N isophthalic acid Chemical compound OC(=O)C1=CC=CC(C(O)=O)=C1 QQVIHTHCMHWDBS-UHFFFAOYSA-N 0.000 description 2
- HSZCZNFXUDYRKD-UHFFFAOYSA-M lithium iodide Chemical compound [Li+].[I-] HSZCZNFXUDYRKD-UHFFFAOYSA-M 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000004014 plasticizer Substances 0.000 description 2
- 230000010287 polarization Effects 0.000 description 2
- 239000004417 polycarbonate Substances 0.000 description 2
- 229920000515 polycarbonate Polymers 0.000 description 2
- 229920000139 polyethylene terephthalate Polymers 0.000 description 2
- 239000005020 polyethylene terephthalate Substances 0.000 description 2
- 229920006254 polymer film Polymers 0.000 description 2
- 239000011118 polyvinyl acetate Substances 0.000 description 2
- 229920002689 polyvinyl acetate Polymers 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 239000002096 quantum dot Substances 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 239000002356 single layer Substances 0.000 description 2
- 150000005846 sugar alcohols Polymers 0.000 description 2
- 238000004381 surface treatment Methods 0.000 description 2
- 239000004094 surface-active agent Substances 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 1
- 229920000089 Cyclic olefin copolymer Polymers 0.000 description 1
- RPNUMPOLZDHAAY-UHFFFAOYSA-N Diethylenetriamine Chemical compound NCCNCCN RPNUMPOLZDHAAY-UHFFFAOYSA-N 0.000 description 1
- 239000004593 Epoxy Substances 0.000 description 1
- PIICEJLVQHRZGT-UHFFFAOYSA-N Ethylenediamine Chemical compound NCCN PIICEJLVQHRZGT-UHFFFAOYSA-N 0.000 description 1
- 238000005033 Fourier transform infrared spectroscopy Methods 0.000 description 1
- SXRSQZLOMIGNAQ-UHFFFAOYSA-N Glutaraldehyde Chemical compound O=CCCCC=O SXRSQZLOMIGNAQ-UHFFFAOYSA-N 0.000 description 1
- DKNPRRRKHAEUMW-UHFFFAOYSA-N Iodine aqueous Chemical compound [K+].I[I-]I DKNPRRRKHAEUMW-UHFFFAOYSA-N 0.000 description 1
- VQTUBCCKSQIDNK-UHFFFAOYSA-N Isobutene Chemical group CC(C)=C VQTUBCCKSQIDNK-UHFFFAOYSA-N 0.000 description 1
- KLDXJTOLSGUMSJ-JGWLITMVSA-N Isosorbide Chemical compound O[C@@H]1CO[C@@H]2[C@@H](O)CO[C@@H]21 KLDXJTOLSGUMSJ-JGWLITMVSA-N 0.000 description 1
- VVQNEPGJFQJSBK-UHFFFAOYSA-N Methyl methacrylate Chemical compound COC(=O)C(C)=C VVQNEPGJFQJSBK-UHFFFAOYSA-N 0.000 description 1
- FXHOOIRPVKKKFG-UHFFFAOYSA-N N,N-Dimethylacetamide Chemical compound CN(C)C(C)=O FXHOOIRPVKKKFG-UHFFFAOYSA-N 0.000 description 1
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 1
- 239000004695 Polyether sulfone Substances 0.000 description 1
- 206010042674 Swelling Diseases 0.000 description 1
- ZJCCRDAZUWHFQH-UHFFFAOYSA-N Trimethylolpropane Chemical compound CCC(CO)(CO)CO ZJCCRDAZUWHFQH-UHFFFAOYSA-N 0.000 description 1
- 125000002339 acetoacetyl group Chemical group O=C([*])C([H])([H])C(=O)C([H])([H])[H] 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-M acrylate group Chemical group C(C=C)(=O)[O-] NIXOWILDQLNWCW-UHFFFAOYSA-M 0.000 description 1
- 239000003522 acrylic cement Substances 0.000 description 1
- 229920001893 acrylonitrile styrene Polymers 0.000 description 1
- 229920005603 alternating copolymer Polymers 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 229910021538 borax Inorganic materials 0.000 description 1
- 150000001639 boron compounds Chemical class 0.000 description 1
- FJDQFPXHSGXQBY-UHFFFAOYSA-L caesium carbonate Chemical compound [Cs+].[Cs+].[O-]C([O-])=O FJDQFPXHSGXQBY-UHFFFAOYSA-L 0.000 description 1
- 229910000024 caesium carbonate Inorganic materials 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000012461 cellulose resin Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 238000007766 curtain coating Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000000593 degrading effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007607 die coating method Methods 0.000 description 1
- 238000003618 dip coating Methods 0.000 description 1
- ROORDVPLFPIABK-UHFFFAOYSA-N diphenyl carbonate Chemical compound C=1C=CC=CC=1OC(=O)OC1=CC=CC=C1 ROORDVPLFPIABK-UHFFFAOYSA-N 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 208000037265 diseases, disorders, signs and symptoms Diseases 0.000 description 1
- KPUWHANPEXNPJT-UHFFFAOYSA-N disiloxane Chemical class [SiH3]O[SiH3] KPUWHANPEXNPJT-UHFFFAOYSA-N 0.000 description 1
- 208000035475 disorder Diseases 0.000 description 1
- 238000010828 elution Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 235000011187 glycerol Nutrition 0.000 description 1
- 150000002334 glycols Chemical class 0.000 description 1
- 229940015043 glyoxal Drugs 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229920001477 hydrophilic polymer Polymers 0.000 description 1
- 125000005462 imide group Chemical group 0.000 description 1
- 230000005764 inhibitory process Effects 0.000 description 1
- 229960002479 isosorbide Drugs 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- SEEYREPSKCQBBF-UHFFFAOYSA-N n-methylmaleimide Chemical compound CN1C(=O)C=CC1=O SEEYREPSKCQBBF-UHFFFAOYSA-N 0.000 description 1
- 125000002560 nitrile group Chemical group 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 239000002736 nonionic surfactant Substances 0.000 description 1
- JFNLZVQOOSMTJK-KNVOCYPGSA-N norbornene Chemical compound C1[C@@H]2CC[C@H]1C=C2 JFNLZVQOOSMTJK-KNVOCYPGSA-N 0.000 description 1
- OTLDLKLSNZMTTA-UHFFFAOYSA-N octahydro-1h-4,7-methanoindene-1,5-diyldimethanol Chemical compound C1C2C3C(CO)CCC3C1C(CO)C2 OTLDLKLSNZMTTA-UHFFFAOYSA-N 0.000 description 1
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 1
- KNCYXPMJDCCGSJ-UHFFFAOYSA-N piperidine-2,6-dione Chemical group O=C1CCCC(=O)N1 KNCYXPMJDCCGSJ-UHFFFAOYSA-N 0.000 description 1
- 229920000636 poly(norbornene) polymer Polymers 0.000 description 1
- 229920002492 poly(sulfone) Polymers 0.000 description 1
- 229920006122 polyamide resin Polymers 0.000 description 1
- 150000004291 polyenes Chemical class 0.000 description 1
- 229920001225 polyester resin Polymers 0.000 description 1
- 239000004645 polyester resin Substances 0.000 description 1
- 229920006393 polyether sulfone Polymers 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 239000009719 polyimide resin Substances 0.000 description 1
- 229920005672 polyolefin resin Polymers 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
- 229920005990 polystyrene resin Polymers 0.000 description 1
- 239000004800 polyvinyl chloride Substances 0.000 description 1
- 229920000915 polyvinyl chloride Polymers 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- SCUZVMOVTVSBLE-UHFFFAOYSA-N prop-2-enenitrile;styrene Chemical compound C=CC#N.C=CC1=CC=CC=C1 SCUZVMOVTVSBLE-UHFFFAOYSA-N 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000007142 ring opening reaction Methods 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 235000009518 sodium iodide Nutrition 0.000 description 1
- 239000004328 sodium tetraborate Substances 0.000 description 1
- 235000010339 sodium tetraborate Nutrition 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 238000004528 spin coating Methods 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 125000003011 styrenyl group Chemical group [H]\C(*)=C(/[H])C1=C([H])C([H])=C([H])C([H])=C1[H] 0.000 description 1
- 239000002335 surface treatment layer Substances 0.000 description 1
- 230000004083 survival effect Effects 0.000 description 1
- 230000008961 swelling Effects 0.000 description 1
- 238000010345 tape casting Methods 0.000 description 1
- 229920001187 thermosetting polymer Polymers 0.000 description 1
- 239000006097 ultraviolet radiation absorber Substances 0.000 description 1
- 230000037303 wrinkles Effects 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
- H10K59/80—Constructional details
- H10K59/8791—Arrangements for improving contrast, e.g. preventing reflection of ambient light
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/30—Polarising elements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
- B32B7/02—Physical, chemical or physicochemical properties
- B32B7/023—Optical properties
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
- G02B1/04—Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of organic materials, e.g. plastics
-
- 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
- G02F1/133528—Polarisers
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
- G09F9/00—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements
- G09F9/30—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B3/00—Ohmic-resistance heating
- H05B3/10—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor
- H05B3/12—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material
- H05B3/14—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material the material being non-metallic
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B33/00—Electroluminescent light sources
- H05B33/02—Details
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2329/00—Polyvinylalcohols, polyvinylethers, polyvinylaldehydes, polyvinylketones or polyvinylketals
- B32B2329/04—Polyvinylalcohol
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Nonlinear Science (AREA)
- Mathematical Physics (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Theoretical Computer Science (AREA)
- Polarising Elements (AREA)
Abstract
Provided is a polarizing plate which can realize an excellent imaging function and a face authentication function without providing a through hole or a transparent part when applied to an image display device having a camera part. The polarizing plate according to an embodiment of the present invention includes a polarizer and a protective layer provided on at least one side of the polarizer, the polarizer is composed of a polyvinyl alcohol resin film containing a dichroic material, and a reflection contrast index of the polarizing plate is 15 or less.
Description
Technical Field
The present invention relates to a polarizing plate and an image display device using the same.
Background
In image display devices (for example, liquid crystal display devices, organic EL display devices, and quantum dot display devices), a polarizing plate is often disposed on at least one side of a display cell due to the image forming method. In recent years, image display devices having a camera section that functions not only as an imaging device but also as a main component of a face authentication system have rapidly become widespread. In order to sufficiently exhibit such an imaging function and a face authentication function, a through hole or a transparent portion (non-polarizing portion) is often provided in a position corresponding to the camera portion in the polarizing plate. However, since the through-hole or the transparent portion often deteriorates the design, a polarizing plate capable of sufficiently performing the photographing function and the face authentication function without providing the through-hole or the transparent portion is desired.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open No. 2014-081482
Disclosure of Invention
Problems to be solved by the invention
The present invention has been made to solve the above-described conventional problems, and a main object of the present invention is to provide a polarizing plate that can realize an excellent image capturing function and a face authentication function without providing a through hole or a transparent portion when applied to an image display device having a camera portion.
Means for solving the problems
The polarizing plate according to an embodiment of the present invention includes a polarizer made of a polyvinyl alcohol resin film containing a dichroic material, and a protective layer provided on at least one side of the polarizer, and has a reflection contrast index of 15 or less.
In 1 embodiment, the polarizer has a thickness of 12 μm or less.
In 1 embodiment, the reflected image contrast index is 13 or less.
In 1 embodiment, the polarizing plate has a protective layer only on one side of the polarizer.
According to another aspect of the present invention, there is provided an image display device. The image display device includes: a display unit, and the polarizing plate disposed on at least one side of the display unit.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the embodiment of the present invention, by controlling the reflectance contrast index to 15 or less, it is possible to provide a polarizing plate which can realize an excellent imaging function and a face authentication function without providing a through hole or a transparent portion when applied to an image display device having a camera portion.
Drawings
Fig. 1 is a schematic cross-sectional view of a polarizing plate according to 1 embodiment of the present invention.
Fig. 2 is a schematic view showing an example of drying and shrinking treatment using a heating roller in the method for manufacturing a polarizing plate used in the polarizing plate according to the embodiment of the present invention.
Detailed Description
Embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.
A. Integral constitution of polarizing plate
Fig. 1 is a schematic cross-sectional view of a polarizing plate according to 1 embodiment of the present invention. The polarizing plate 100 includes: a polarizer 10, a 1 st protective layer (outer protective layer) 20 disposed on one side of the polarizer 10 (for example, the side opposite to the display unit when the polarizing plate is applied to the image display device), and a 2 nd protective layer (inner protective layer) 30 disposed on the other side of the polarizer 10 (for example, the side of the display unit when the polarizing plate is applied to the image display device). Depending on the purpose or the like, either the 1 st protective layer 20 or the 2 nd protective layer 30 may be omitted. The polarizer 10 is made of a polyvinyl alcohol (PVA) resin film containing a dichroic material (typically, iodine or a dichroic dye).
In the embodiment of the present invention, the reflection contrast index is 15 or less, preferably 14.5 or less, more preferably 13 or less, and further preferably 12 or less. The lower the reflectance contrast index is, the more preferable the lower the reflectance contrast index is, the lower limit may be 5, for example. When the index of contrast of the reflected image is in such a range, the transmitted wavefront aberration (optical distortion of light transmitted through the polarizing plate, which will be described later in detail) can be reduced. As a result, when applied to an image display device having a camera unit, it is possible to realize an excellent image capturing function and a face authentication function without providing a through hole or a transparent portion. The technical meaning of specifying the index of the reflected image contrast is explained below. One of the causes of the large transmitted wavefront aberration is presumed to be related to the surface roughness (e.g., arithmetic mean roughness Ra) of the polarizer. The present inventors have intensively studied the relationship between the transmitted wavefront aberration and the surface roughness of the polarizer, and as a result, they have found that the transmitted wavefront aberration cannot be appropriately controlled even if the surface roughness of the polarizer is controlled. Further, the present inventors have found that transmission wavefront aberration can be appropriately controlled by controlling a reflection image contrast index which is a characteristic of the entire polarizing plate, based on such new findings and further repeated experiments, and have completed the present invention. The reason why the transmitted wavefront aberration can be appropriately controlled by controlling the index of contrast of the reflected light, not the surface roughness of the polarizer, is theoretically unclear, and it is assumed that the individual components of the polarizing plate and/or the mutual optical components are optimized as a whole.
As described above, the index of the reflected image contrast reflects individual and/or mutual optical elements of the constituent elements of the polarizing plate (for example, stripes of the polarizer, refraction and/or scattering at the interface between the polarizer and the protective layer, and irregularities of the protective layer). The reflectance contrast index can be determined as follows. Irradiating Light from a special illumination device for inspection (manufactured by Nippon technology center, ltd., "S-Light") to a polarizing plate at an angle of 45 DEG in a darkroom environment; reading the image of the reflected image in the form of digital data; image processing was performed on a 100mm × 100mm area, and the luminance unevenness was obtained as a standard deviation, which was used as a reflection contrast index. More specifically, the luminance of a pixel of an image is expressed in numerical values on a scale of 0 to 255, and the standard deviation is obtained and used as a reflected image contrast index.
The polarizing plate preferably has a small wavefront aberration in transmission as described above. Thus, when applied to an image display device having a camera unit, it is possible to realize an excellent image capturing function and a face authentication function without providing a through hole or a transparent portion. The wavefront aberration is an index indicating optical distortion of light transmitted through the polarizing plate, and means a shift of light transmitted through the polarizing plate from an ideal wavefront (spherical surface). Therefore, if the transmitted wavefront aberration is too large, the light transmitted through the polarizing plate may be greatly deviated from the ideal wavefront, and the light beams emitted from 1 point of the object may not converge to 1 point, thereby causing blurring or distortion of the image. Such a problem of imaging may prevent correct authentication in the face authentication system. The transmitted wavefront aberration is preferably 100nm or less, more preferably 50nm or less, further preferably 30nm or less, and particularly preferably 25nm or less. The smaller the transmitted wavefront aberration is, the more preferable it is, and the lower limit thereof may be, for example, 3nm. Such transmitted wavefront aberration can be achieved by controlling the reflected image contrast index to be equal to or less than a predetermined value as described above. The transmitted wavefront aberration is representatively expressed by Pv · λ. Here, pv represents the difference between the maximum value and the minimum value of the transmitted wavefront aberration in the measurement range (Peak-Valley), and represents the ratio of the distance to the wavelength of the incident light. For example, when the transmitted wavefront aberration is a distance of 1/10 with respect to the wavelength of the incident light, pv =0.1.λ is the wavelength (nm) of the incident light. In 1 embodiment, the transmitted wavefront aberration can be measured using a HeNe laser with a wavelength of 632.8 nm.
A-1. Polarizer
As described above, the polarizing element is composed of a PVA-based resin film containing a dichroic material (typically, iodine or a dichroic dye). The dichroic substance is preferably iodine. The polarizer may be formed of a single-layer resin film or may be formed of a laminate of two or more layers.
Specific examples of the polarizing material formed of a single-layer resin film include a hydrophilic polymer film such as a polyvinyl alcohol (PVA) film, a partially formalized PVA film, or an ethylene-vinyl acetate copolymer partially saponified film, which is dyed or stretched with a dichroic material such as iodine or a dichroic dye, a polyene-based oriented film such as a dehydrated PVA product or a desalted polyvinyl chloride product, and the like. From the viewpoint of excellent optical properties, a polarizer obtained by uniaxially stretching a PVA-based film dyed with iodine is preferably used. The iodine-based dyeing is performed by, for example, immersing a PVA-based 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. In addition, dyeing may be performed after stretching. The PVA-based film is subjected to swelling treatment, crosslinking treatment, washing treatment, drying treatment, and the like as necessary. For example, by immersing the PVA-based film in water and washing it with water before dyeing, stains and an antiblocking agent on the surface of the PVA-based film can be washed, and the PVA-based film can be swollen to prevent uneven dyeing or the like.
Specific examples of the polarizer obtained using the laminate include a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, and a polarizer obtained by coating a laminate of a resin substrate and a PVA-based resin layer formed on the resin substrate. A polarizer obtained by using a laminate of a resin substrate and a PVA-based resin layer formed on the resin substrate is produced, for example, as follows: coating a PVA-based resin solution on a resin base material, and drying the PVA-based resin solution to form a PVA-based resin layer on the resin base material, thereby obtaining a laminate of the resin base material and the PVA-based resin layer; the laminate was stretched and dyed to prepare a polarizing plate from the PVA-based resin layer. In the present embodiment, the stretching typically includes immersing the laminate in an aqueous boric acid solution and stretching. Further, the stretching may further include subjecting the laminate to in-air stretching at a high temperature (for example, 95 ℃ or higher) before stretching in the aqueous boric acid solution, if necessary. The obtained laminate of the resin base material and the polarizing plate may be used as it is (that is, the resin base material may be used as a protective film for the polarizing plate), or the resin base material may be peeled off from the laminate of the resin base material and the polarizing plate, and an arbitrary appropriate protective film suitable for the purpose may be laminated on the peeled surface. Details of a method for producing such a polarizer are described in, for example, japanese patent laid-open publication No. 2012-73580 and japanese patent No. 6470455. The entire disclosures of these publications are incorporated herein by reference.
As the PVA-based resin forming the PVA-based resin film, any suitable resin can be used. For example, polyvinyl alcohol and ethylene-vinyl alcohol copolymer are mentioned. Polyvinyl alcohol is obtained by saponifying polyvinyl acetate. The ethylene-vinyl alcohol copolymer is obtained by saponifying an ethylene-vinyl acetate copolymer. The saponification degree of the PVA resin is usually 85 mol% to 100 mol%, preferably 95.0 mol% to 99.9 mol%, and more preferably 99.0 mol% to 99.5 mol%. The degree of saponification can be determined in accordance with JIS K6726-1994. By using the PVA-based resin having such a saponification degree, a polarizing plate having excellent durability can be obtained. If the degree of saponification is too high, gelation may occur.
The average polymerization degree of the PVA-based resin can be appropriately selected according to the purpose. The average polymerization degree is usually 1000 to 10000, preferably 1200 to 5000, and more preferably 1500 to 4500. The average degree of polymerization can be determined in accordance with JIS K6726-1994.
The iodine concentration in the PVA-based resin film (polarizer) is, for example, 5.0 wt% to 12.0 wt%. The boric acid concentration in the PVA-based resin film is, for example, 12 to 25 wt%.
The thickness of the polarizer is, for example, 12 μm or less, preferably 8 μm or less, more preferably 7 μm or less, and still more preferably 6 μm or less. On the other hand, the thickness of the polarizer is preferably 1 μm or more, more preferably 2 μm or more. A desired index of reflected image contrast is more easily obtained as the thickness of the polarizer is thicker, but according to the embodiment of the present invention, a desired index of reflected image contrast can be achieved even with such a thin polarizer.
The polarizing element preferably exhibits dichroism of absorption at any wavelength of 380nm to 780 nm. The polarizing material preferably has a monomer transmittance of 40.0% to 46.0%, more preferably 40.5% to 43.0%. The degree of polarization of the polarizer is preferably 99.9% or more, more preferably 99.95% or more, and still more preferably 99.98% or more.
A-2 protective layer
The 1 st and 2 nd protective layers are formed of any suitable thin film that can be used as a protective layer of a polarizer. Specific examples of the material as the main component of the film include cellulose resins such as Triacetylcellulose (TAC), polyester resins, polyvinyl alcohol resins, polycarbonate resins, polyamide resins, polyimide resins, polyether sulfone resins, polysulfone resins, polystyrene resins, polynorbornene resins, polyolefin resins, (meth) acrylic resins, acetate resins, and the like transparent resins. Further, there may be mentioned thermosetting resins such as (meth) acrylic, urethane, (meth) acrylic urethane, epoxy, silicone and the like, ultraviolet-curable resins and the like. Further, for example, a glassy polymer such as a siloxane polymer can be cited. Further, the polymer film described in Japanese patent application laid-open No. 2001-343529 (WO 01/37007) may be used. As a material of the film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in a side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in a side chain can be used, and for example, a resin composition having an alternating copolymer of isobutylene and N-methylmaleimide and an acrylonitrile-styrene copolymer can be mentioned. The polymer film may be, for example, an extrusion molded product of the resin composition.
When the polarizing plate 100 is applied to an image display device, the thickness of the 1 st protective layer (outer protective layer) 20 disposed on the side opposite to the display cell is typically 300 μm or less, preferably 100 μm or less, more preferably 5 μm to 80 μm, and still more preferably 10 μm to 60 μm. When the surface treatment is performed, the thickness of the outer protective layer is a thickness including the thickness of the surface treatment layer.
When the polarizing plate 100 is applied to an image display device, the thickness of the 2 nd protective layer (inner protective layer) 30 disposed on the display cell side is preferably 5 μm to 200 μm, more preferably 10 μm to 100 μm, and still more preferably 10 μm to 60 μm. In 1 embodiment, the inner protective layer is preferably optically isotropic. In the present specification, "optically isotropic" means that the in-plane retardation Re (550) is 0nm to 10nm and the retardation Rth (550) in the thickness direction is-10 nm to +10nm. In another embodiment, the inner protective layer is a retardation layer having any suitable retardation value. In this case, the in-plane retardation Re (550) of the retardation layer is, for example, 110nm to 150nm, and the angle formed by the slow axis and the absorption axis of the polarizer is, for example, 40 ° to 50 °. "Re (550)" is an in-plane retardation measured at 23 ℃ with light having a wavelength of 550nm, represented by the formula: re = (nx-ny) × d. "Rth (550)" is a phase difference in the thickness direction measured at 23 ℃ with light having a wavelength of 550nm, represented by the formula: re = (nx-nz). Times.d. Here, "nx" is a refractive index in a direction in which a refractive index in a plane is maximum (i.e., slow axis direction), "ny" is a refractive index in a direction orthogonal to the slow axis in a plane (i.e., fast axis direction), "nz" is a refractive index in a thickness direction, and "d" is a thickness (nm) of the layer (thin film). As described above, the 2 nd protective layer (inner protective layer) 30 may preferably be omitted.
B. Method for manufacturing polarizing piece
The polarizer can be produced, for example, by a method including the following steps: forming a polyvinyl alcohol resin layer (PVA-based resin layer) containing a halide and a polyvinyl alcohol resin (PVA-based resin) on one side of a long thermoplastic resin base material to form a laminate; and subjecting the laminate to an in-air auxiliary stretching treatment, a dyeing treatment, an in-water stretching treatment, and a drying shrinkage treatment in this order, wherein the drying shrinkage treatment is performed by heating the laminate while conveying the laminate in the longitudinal direction, thereby shrinking the laminate by 2% or more in the width direction. The content of the halide in the PVA-based resin layer is preferably 5 to 20 parts by weight based on 100 parts by weight of the PVA-based resin. The drying shrinkage treatment is preferably carried out using a heated roller, and the temperature of the heated roller is preferably 60 to 120 ℃. The shrinkage in the width direction of the laminate by the drying shrinkage treatment is preferably 2% or more. According to such a manufacturing method, the polarizing plate described in the above item B can be obtained. In particular, by producing a laminate having a PVA-based resin layer containing a halide, stretching the laminate in multiple stages including aerial auxiliary stretching and underwater stretching, and heating the stretched laminate with a heating roller, a polarizing material having excellent optical properties (typically, a monomer transmittance and a polarization degree) and suppressed variations in optical properties can be obtained. Specifically, by using a heating roller in the drying and shrinking treatment step, the entire laminate can be uniformly shrunk while the laminate is conveyed. This can improve the optical characteristics of the obtained polarizer, stably produce a polarizer having excellent optical characteristics, and suppress variations in the optical characteristics (particularly, the single transmittance) of the polarizer.
B-1 preparation of laminate
As a method for producing a laminate of the thermoplastic resin substrate and the PVA-based resin layer, any appropriate method can be adopted. Preferably, a PVA-based resin layer is formed on the thermoplastic resin substrate by applying a coating solution containing a halide and a PVA-based resin to the surface of the thermoplastic resin substrate and drying the coating solution. As described above, the content of the halide in the PVA-based resin layer is preferably 5 to 20 parts by weight based on 100 parts by weight of the PVA-based resin.
As a method for applying the coating liquid, any appropriate method can be adopted. Examples of the method include roll coating, spin coating, wire bar coating, dip coating, die coating, curtain coating, spray coating, and knife coating (comma coating). The coating and drying temperature of the coating liquid is preferably 50 ℃ or higher.
The thickness of the PVA resin layer is preferably 3 to 40 μm, and more preferably 3 to 20 μm.
Before the PVA-based resin layer is formed, the thermoplastic resin substrate may be subjected to a surface treatment (for example, corona treatment), or an easy-adhesion layer may be formed on the thermoplastic resin substrate. By performing such treatment, the adhesion between the thermoplastic resin substrate and the PVA-based resin layer can be improved.
B-1-1. Thermoplastic resin base Material
As the thermoplastic resin substrate, any suitable thermoplastic resin film can be used. Details of the thermoplastic resin substrate are described in, for example, japanese patent laid-open No. 2012-73580. The entire disclosure of this publication is incorporated herein by reference.
B-1-2 coating liquid
The coating liquid contains a halide and a PVA-based resin as described above. The coating liquid is typically a solution obtained by dissolving the halide and the PVA-based resin in a solvent. Examples of the solvent include water, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, various glycols, polyhydric alcohols such as trimethylolpropane, and amines such as ethylenediamine and diethylenetriamine. These may be used alone or in combination of two or more. Among these, water is preferable. The concentration of the PVA-based resin in the solution is preferably 3 to 20 parts by weight based on 100 parts by weight of the solvent. At such a resin concentration, a uniform coating film can be formed in close contact with the thermoplastic resin substrate. The content of the halide in the coating liquid is preferably 5 to 20 parts by weight based on 100 parts by weight of the PVA-based resin.
Additives may be compounded in the coating liquid. Examples of the additives include plasticizers and surfactants. Examples of the plasticizer include polyhydric alcohols such as ethylene glycol and glycerin. Examples of the surfactant include nonionic surfactants. These can be used for the purpose of further improving the uniformity, dyeability and stretchability of the PVA-based resin layer obtained.
As the PVA-based resin, any suitable resin can be used. For example, polyvinyl alcohol and ethylene-vinyl alcohol copolymer are listed. Polyvinyl alcohol is obtained by saponifying polyvinyl acetate. The ethylene-vinyl alcohol copolymer is obtained by saponifying an ethylene-vinyl acetate copolymer. The saponification degree of the PVA resin is usually 85 mol% to 100 mol%, preferably 95.0 mol% to 99.95 mol%, and more preferably 99.0 mol% to 99.93 mol%. The degree of saponification can be determined in accordance with JIS K6726-1994. By using the PVA-based resin having such a saponification degree, a polarizing plate having excellent durability can be obtained. If the degree of saponification is too high, gelation may occur. As described above, the PVA-based resin preferably contains an acetoacetyl group-modified PVA-based resin.
The average polymerization degree of the PVA-based resin can be appropriately selected according to the purpose. The average polymerization degree is usually 1000 to 10000, preferably 1200 to 4500, and more preferably 1500 to 4300. The average degree of polymerization can be determined in accordance with JIS K6726-1994.
As the halide, any suitable halide can be used. For example, iodide and sodium chloride are mentioned. Examples of the iodide include potassium iodide, sodium iodide, and lithium iodide. Among these, potassium iodide is preferable.
The amount of the halide in the coating liquid is preferably 5 to 20 parts by weight based on 100 parts by weight of the PVA-based resin, and more preferably 10 to 15 parts by weight based on 100 parts by weight of the PVA-based resin. If the amount of the halide exceeds 20 parts by weight based on 100 parts by weight of the PVA-based resin, the halide may bleed out, and the finally obtained polarizer may become cloudy.
In general, the orientation of polyvinyl alcohol molecules in a PVA-based resin is increased by stretching the PVA-based resin layer, but when the stretched PVA-based resin layer is immersed in a liquid containing water, the orientation of polyvinyl alcohol molecules may be disordered and the orientation may be decreased. In particular, when a laminate of a thermoplastic resin and a PVA-based resin layer is stretched in boric acid water, the orientation degree tends to be remarkably decreased when the laminate is stretched in boric acid water at a relatively high temperature in order to stabilize the stretching of the thermoplastic resin. For example, stretching of a PVA film itself in boric acid water is generally performed at 60 ℃, whereas stretching of a laminate of a-PET (thermoplastic resin substrate) and a PVA-based resin layer is performed at a high temperature such as a temperature of about 70 ℃, and in this case, the orientation of the PVA at the initial stage of stretching is reduced in a stage before it is raised by underwater stretching. In contrast, by producing a laminate of a PVA-based resin layer containing a halide and a thermoplastic resin substrate and stretching the laminate at a high temperature in air (auxiliary stretching) before stretching the laminate in boric acid water, crystallization of the PVA-based resin in the PVA-based resin layer of the laminate after the auxiliary stretching can be promoted. As a result, when the PVA-based resin layer is immersed in a liquid, disorder of the orientation of the polyvinyl alcohol molecules and reduction of the orientation can be suppressed as compared with the case where the PVA-based resin layer does not contain a halide. This can improve the optical properties of the polarizer obtained through a treatment step of immersing the laminate in a liquid, such as dyeing treatment and underwater stretching treatment.
B-2. Auxiliary stretching treatment in air
In particular, in order to obtain high optical properties, a 2-stage stretching method in which dry stretching (auxiliary stretching) and boric acid underwater stretching are combined is preferable. By introducing the auxiliary stretching as in the 2-stage stretching, the thermoplastic resin substrate can be stretched while suppressing crystallization, the problem that the stretchability is reduced by excessive crystallization of the thermoplastic resin substrate when the thermoplastic resin substrate is stretched in boric acid water thereafter can be solved, and the laminate can be stretched at a higher ratio. Further, when a PVA-based resin is coated on a thermoplastic resin substrate, in order to suppress the influence of the glass transition temperature of the thermoplastic resin substrate, the coating temperature needs to be lowered as compared with the case where the PVA-based resin is usually coated on a metal roll, and as a result, there is a problem that crystallization of the PVA-based resin is relatively lowered and sufficient optical characteristics cannot be obtained. In contrast, by introducing the auxiliary stretching, even when the PVA-based resin is applied to the thermoplastic resin, the crystallinity of the PVA-based resin can be improved, and high optical characteristics can be achieved. Further, by simultaneously improving the orientation of the PVA-based resin in advance, when the PVA-based resin is immersed in water in the subsequent dyeing step or stretching step, problems such as reduction in the orientation and dissolution of the PVA-based resin can be prevented, and high optical properties can be achieved.
The stretching method of the in-air auxiliary stretching may be fixed-end stretching (for example, a method of stretching using a tenter) or free-end stretching (for example, a method of uniaxially stretching a laminate by passing the laminate between rolls having different peripheral speeds). In 1 embodiment, the stretching method by the in-air auxiliary stretching may be, for example, biaxial stretching using a tenter stretching machine. By appropriately setting the stretching conditions of the biaxial stretching, a predetermined bidirectionality can be imparted to the obtained polarizer. As a result, a polarizer having a desired piercing strength can be realized.
The stretching ratio in the longitudinal direction of the in-air auxiliary stretching is preferably 2.3 times or more, and more preferably 2.4 times to 3.5 times. In the embodiment of the present invention, the residual width ratio (width after shrinkage:% to the original width) is controlled by biaxial stretching as described above. Specifically, the difference between the width residual ratio of the air-assisted stretching (i.e., after the air-assisted stretching) and the free shrink width residual ratio is preferably 2% or more, more preferably 3% or more, and still more preferably 5% or more. The maximum value of the difference may be 15%, for example. Here, the free shrink width residual ratio is a width residual ratio when free end stretching is performed in the longitudinal direction at the same stretching ratio. Specifically, the residual free shrink width ratio when the stretch ratio is x times can be (1/x) 1/2 ) X 100. For example, when the stretching ratio is 2.4 times, the free shrink width survival rate is (1/(2.4) 1/2 ) X 100=64.5%. This is considered to be because, when stretching is performed in the longitudinal direction in free shrinkage, the width direction and the thickness direction shrink at the same rate. The maximum stretching ratio (longitudinal direction) when the air-assisted stretching and the underwater stretching are combined is preferably 5.0 times or more, more preferably 5.5 times or more, and still more preferably 6.0 times or more, with respect to the original length of the laminate. In the present specification, "maximum stretching ratio" means a stretching ratio immediately before the laminate breaks, and means a value which is lower by 0.2 than a value at which the laminate breaks, separately from the maximum stretching ratio.
The stretching temperature of the in-air auxiliary stretching may be set to any appropriate value depending on the material for forming the thermoplastic resin base material, the stretching method, and the like. The stretching temperature is preferably not lower than the glass transition temperature (Tg) of the thermoplastic resin substrate, and further preferably not lower than the glass transition temperature (Tg) of the thermoplastic resin substrateThe glass transition temperature (Tg) +10 ℃ or higher, particularly preferably Tg +15 ℃ or higher, of the thermoplastic resin substrate is preferable. On the other hand, the upper limit of the stretching temperature is preferably 170 ℃. By stretching at such a temperature, rapid progress of crystallization of the PVA-based resin can be suppressed, and defects caused by the crystallization (for example, inhibition of orientation of the PVA-based resin layer due to stretching) can be suppressed. The crystallization index of the PVA-based resin after the in-air auxiliary stretching is preferably 1.3 to 1.8, more preferably 1.4 to 1.7. The crystallization index of the PVA-based resin can be measured by an ATR method using a fourier transform infrared spectrometer. Specifically, measurement was performed using polarized light as measurement light, and 1141cm of the obtained spectrum was used -1 And 1440cm -1 The crystallization index of (2) was calculated according to the following equation.
Crystallinity index = (I) C /I R )
Wherein the content of the first and second substances,
I C : 1141cm when measurement is performed so that measurement light is incident thereon -1 Strength of
I R : 1440cm for incidence of measurement light and measurement -1 The strength of (2).
B-3. Insolubilization treatment, dyeing treatment and crosslinking treatment
If necessary, after the in-air auxiliary stretching treatment, an insolubilization treatment is performed between the stretching treatment in water and the dyeing treatment. The insolubilization treatment is typically performed by immersing the PVA-based resin layer in an aqueous boric acid solution. The dyeing treatment is typically performed by dyeing the PVA-based resin layer with a dichroic substance (typically, iodine). If necessary, a crosslinking treatment is performed after the dyeing treatment and before the underwater stretching treatment. The crosslinking treatment is typically performed by immersing the PVA-based resin layer in an aqueous boric acid solution. Details of the insolubilization treatment, dyeing treatment and crosslinking treatment are described in, for example, japanese patent laid-open No. 2012-73580 (described above).
B-4 stretching treatment in water
The underwater stretching treatment is performed by immersing the laminate in a stretching bath. The stretching in water can be performed at a temperature lower than the glass transition temperature (typically, about 80 ℃) of the thermoplastic resin substrate or the PVA-based resin layer, and the PVA-based resin layer can be stretched at a high magnification while suppressing crystallization thereof. As a result, a polarizer having excellent optical characteristics can be manufactured.
Any suitable method may be used for stretching the laminate. Specifically, the stretching may be performed at a fixed end or at a free end (for example, a method of passing the laminate between rollers having different peripheral speeds to perform uniaxial stretching). Free end stretching is preferably chosen. The stretching of the laminate may be performed in one stage or may be performed in multiple stages. When the stretching is performed in multiple stages, the stretching ratio (maximum stretching ratio) of the laminate described later is the product of the stretching ratios in the respective stages.
The underwater stretching is preferably performed by immersing the laminate in an aqueous boric acid solution (boric acid underwater stretching). By using the aqueous boric acid solution as the stretching bath, rigidity that resists the tension applied during stretching and water resistance that does not dissolve in water can be imparted to the PVA-based resin layer. Specifically, boric acid generates tetrahydroxyborate anions in an aqueous solution and crosslinks with the PVA-based resin through hydrogen bonds. As a result, the PVA-based resin layer can be provided with rigidity and water resistance and can be stretched well, and a polarizer having excellent optical characteristics can be produced.
The aqueous boric acid solution is preferably obtained by dissolving boric acid and/or a borate in water as a solvent. The boric acid concentration is preferably 1 to 10 parts by weight, more preferably 2.5 to 6 parts by weight, and particularly preferably 3 to 5 parts by weight, based on 100 parts by weight of water. By setting the boric acid concentration to 1 part by weight or more, the dissolution of the PVA-based resin layer can be effectively suppressed, and a polarizer with higher characteristics can be obtained. In addition to boric acid or a borate, an aqueous solution obtained by dissolving a boron compound such as borax, glyoxal, glutaraldehyde, or the like in a solvent may be used.
The above-mentioned stretching bath (aqueous boric acid solution) is preferably compounded with an iodide. By adding an iodide, elution of iodine adsorbed to the PVA-based resin layer can be suppressed. Specific examples of the iodide are as described above. The concentration of the iodide is preferably 0.05 to 15 parts by weight, more preferably 0.5 to 8 parts by weight, based on 100 parts by weight of water.
The stretching temperature (liquid temperature of the stretching bath) and the immersion time of the laminate in the stretching bath may be appropriately set depending on the configuration of the protective layer (typically, the material, and whether the polarizing material is disposed on one side or both sides). The stretching temperature may be, for example, 70 ℃ or lower, may be, for example, 67 ℃ or lower, may be, for example, 66 ℃ or lower, and may be, for example, 65 ℃ or lower. The lower limit of the stretching temperature may be, for example, 50 ℃ and may be, for example, 55 ℃. The immersion time of the laminate in the stretching bath may be, for example, 50 seconds or more, 55 seconds or more, or 60 seconds or more. The upper limit of the dipping time may be, for example, 100 seconds. The combination of the stretching temperature and the immersion time may be, for example, 55 to 66 ℃/55 seconds or more, or, for example, 60 to 66 ℃/60 seconds to 80 seconds. Boric acid underwater stretching is usually performed at around 70 ℃ for about 50 seconds, but the present inventors have found that by lowering the stretching temperature by several degrees c and extending the immersion time, the reflectance contrast index can be significantly reduced without degrading the optical characteristics of the polarizer. This is an unexpected excellent effect. Further, it has been found that: with the configuration of the protective layer, the same effect can be obtained by only lowering the stretching temperature or only extending the immersion time.
The stretching ratio by underwater stretching is preferably 1.5 times or more, more preferably 3.0 times or more. The total stretch ratio of the laminate is preferably 5.0 times or more, and more preferably 5.5 times or more, the original length of the laminate. By achieving such a high stretch ratio, a polarizer having extremely excellent optical characteristics can be manufactured. Such a high stretch ratio can be achieved by using an underwater stretching method (boric acid underwater stretching).
B-5 drying shrinkage treatment
The drying shrinkage treatment may be performed by heating the entire region to heat the region, or may be performed by heating the transport roller (using a so-called hot roller) (hot roller drying method). Both are preferably used. By drying using a hot roller, the laminate can be effectively prevented from curling by heating, and a polarizer having excellent appearance can be produced. Specifically, by drying the laminate in a state of being along the heating roller, the crystallization of the thermoplastic resin substrate can be effectively promoted to increase the crystallinity, and the crystallinity of the thermoplastic resin substrate can be favorably increased even at a low drying temperature. As a result, the thermoplastic resin substrate has increased rigidity, and is able to withstand shrinkage of the PVA-based resin layer due to drying, and curling can be suppressed. Further, since the laminate can be dried while maintaining a flat state by using the heating roller, not only curling but also wrinkles can be suppressed. In this case, the optical properties can be improved by shrinking the laminate in the width direction by the drying shrinkage treatment. This is because the orientation of PVA and PVA/iodine complex can be effectively improved. The shrinkage in the width direction of the laminate by the drying shrinkage treatment is preferably 1% to 10%, more preferably 2% to 8%, and particularly preferably 4% to 6%. By using the heating roller, the laminate can be continuously shrunk in the width direction while being conveyed, and high productivity can be achieved.
Fig. 2 is a schematic diagram showing an example of the drying shrinkage treatment. In the drying shrinkage process, the stacked body 200 is dried while being conveyed by the conveying rollers R1 to R6 and the guide rollers G1 to G4 heated to a predetermined temperature. In the illustrated example, the conveying rollers R1 to R6 are disposed so as to alternately and continuously heat the surface of the PVA resin layer and the surface of the thermoplastic resin substrate, but the conveying rollers R1 to R6 may be disposed so as to continuously heat only one surface (for example, the surface of the thermoplastic resin substrate) of the stacked body 200, for example.
The drying condition can be controlled by adjusting the heating temperature of the conveying roller (temperature of the heating roller), the number of heating rollers, the contact time with the heating roller, and the like. The temperature of the heated roller is preferably 60 to 120 ℃, more preferably 65 to 100 ℃, and particularly preferably 70 to 80 ℃. An optical laminate which can satisfactorily suppress curling by increasing the crystallinity of a thermoplastic resin and has extremely excellent durability can be produced. The temperature of the heating roller may be measured by a contact thermometer. In the example of the figure, 6 conveying rollers are provided, but there is no particular limitation as long as there are a plurality of conveying rollers. The conveying rollers are usually provided in an amount of 2 to 40, preferably 4 to 30. The contact time (total contact time) between the laminate and the heating roller is preferably 1 to 300 seconds, more preferably 1 to 20 seconds, and still more preferably 1 to 10 seconds.
The heating roller may be disposed in a heating furnace (e.g., an oven) or may be disposed in a general production line (room temperature environment). Preferably, the heating furnace is provided with an air blowing means. By using drying by the heating roller and hot air drying in combination, a rapid temperature change between the heating rollers can be suppressed, and the shrinkage in the width direction can be easily controlled. The temperature of the hot air drying is preferably 30 to 100 ℃. The hot air drying time is preferably 1 to 300 seconds. The wind speed of the hot wind is preferably about 10m/s to 30 m/s. The wind speed is the wind speed in the heating furnace and can be measured by a digital wind speed meter of a miniature blade type.
B-6 other treatment
It is preferable to perform the washing treatment after the stretching treatment in water and before the drying shrinkage treatment. The cleaning treatment is typically performed by immersing the PVA-based resin layer in an aqueous potassium iodide solution.
C. Image display device
The polarizing plate described in the above items a and B can be applied to an image display device. Therefore, such an image display device is also included in the embodiments of the present invention. The image display device includes: a display unit, and the polarizing plate according to the above items A and B disposed on at least one side of the display unit. Examples of the image display device include a liquid crystal display device and an organic Electroluminescence (EL) display device. The configuration of the image display device is well known in the art, and therefore, a detailed description thereof will be omitted.
Examples
The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Evaluation items in examples are as follows.
(1) Reflectance contrast index
The polarizing plates obtained in examples and comparative examples were placed on a horizontal surface in a small darkroom. A special illumination device for inspection (manufactured by Japan technology center, "S-Light") was used as a Light source, and Light from the Light source was irradiated to the polarizing plate at an angle of 45 degrees. In this case, the polarizing plate is disposed so that the absorption axis direction of the polarizing plate is perpendicular to the irradiation direction of the light source. The polarizing plate was bonded to a light-shielding black acrylic plate via an acrylic adhesive (thickness: 20 μm). In the case of a polarizing plate having a protective layer on one side, the polarizer surface is brought into contact with an adhesive, and in the case of a polarizing plate having protective layers on both sides, the inner protective layer surface is brought into contact with an adhesive. In addition, the black acrylic plate has a sufficiently smaller index of contrast of reflected light than the polarizing plate, and therefore does not affect the measurement result. A reflected image projected onto a screen provided on a wall surface in a darkroom is photographed by a camera, and an image of the reflected image is read in a digital data form. Image processing was performed on a 100mm × 100mm area of the read image, and the luminance unevenness was obtained as a standard deviation and used as a reflection contrast index. More specifically, the luminance of a pixel of an image is expressed in numerical values on a scale of 0 to 255, and the standard deviation is obtained and used as a reflected image contrast index.
(2) Transmitted wave front aberration
The polarizing plates obtained in examples and comparative examples were placed in a measuring apparatus (product of ZYGO, verifire interferometer system) and measured. The light source used a HeNe laser having a wavelength of 632.8nm, and the spot diameter of the incident light was set to 1mm. The transmitted wavefront aberration calculated from the interference light is obtained using an application program of spherical transmitted wavefront measurement.
[ example 1]
1. Fabrication of polarizing elements
As the thermoplastic resin base material, a long amorphous isophthalic acid copolymerized polyethylene terephthalate film (thickness: 100 μm) having a Tg of about 75 ℃ was used, and one surface of the resin base material was subjected to corona treatment.
In the following, with 9:1 an aqueous PVA solution (coating solution) was prepared by mixing 100 parts by weight of a PVA resin comprising polyvinyl alcohol (degree of polymerization 4200 and degree of saponification 99.2 mol%) and acetoacetyl-modified PVA (trade name "GOHSEFIMER" manufactured by Nippon synthetic chemical industries, ltd.) and adding 13 parts by weight of potassium iodide to the mixture, and dissolving the mixture in water.
The aqueous PVA solution was applied to the corona-treated surface of the resin substrate and dried at 60 ℃ to form a PVA-based resin layer having a thickness of 13 μm, thereby producing a laminate.
The obtained laminate was uniaxially stretched in the longitudinal direction (longitudinal direction) to 2.4 times in an oven at 130 ℃ (in-air auxiliary stretching treatment).
Next, the laminate was immersed in an insolubilization bath (an aqueous boric acid solution prepared by adding 4 parts by weight of boric acid to 100 parts by weight of water) at a liquid temperature of 40 ℃ for 30 seconds (insolubilization treatment).
Next, the resultant polarizer was immersed for 60 seconds (dyeing treatment) in a dyeing bath (aqueous iodine solution prepared by mixing iodine and potassium iodide at a weight ratio of 1:7 with respect to 100 parts by weight of water) at a liquid temperature of 30 ℃.
Next, the substrate was immersed in a crosslinking bath (an aqueous boric acid solution prepared by adding 3 parts by weight of potassium iodide and 5 parts by weight of boric acid to 100 parts by weight of water) at a liquid temperature of 40 ℃ for 30 seconds (crosslinking treatment).
Thereafter, the laminate was immersed in an aqueous boric acid solution (boric acid concentration 4 wt%, potassium iodide concentration 5 wt%) having a liquid temperature of 64 ℃ and uniaxially stretched (underwater stretching treatment) between rolls having different peripheral speeds so that the total stretching ratio was 5.5 times in the longitudinal direction (longitudinal direction). The laminate in the underwater stretching treatment was immersed in the boric acid aqueous solution for 75 seconds.
Thereafter, the laminate was immersed in a cleaning bath (aqueous solution prepared by adding 4 parts by weight of potassium iodide to 100 parts by weight of water) at a liquid temperature of 20 ℃.
Thereafter, the sheet was brought into contact with a heating roll made of SUS having a surface temperature of about 75 ℃ while being dried in an oven maintained at about 90 ℃ (drying shrinkage treatment).
In this manner, a polarizing plate having a thickness of about 5 μm was formed on the resin substrate.
2. Manufacture of polarizing plate
A polycarbonate-based resin film (40 μm) was bonded as a protective layer to the surface (the surface opposite to the resin substrate) of the polarizer obtained above with an ultraviolet-curable adhesive. Specifically, the curable adhesive was applied so that the total thickness thereof became about 1.0 μm, and was bonded by a roll press. Thereafter, the adhesive is cured by irradiating UV light from the cycloolefin film side. Then, the resin base was peeled off to obtain a polarizing plate having a structure of a polycarbonate resin film (protective layer)/polarizer. The obtained polarizing plate was subjected to the evaluations (1) and (2). The results are shown in Table 1.
The polycarbonate resin film was produced as follows. 47.19 parts by mass of tricyclodecanedimethanol (hereinafter, sometimes simply referred to as "TCDDM"), 175.1 parts by mass of diphenyl carbonate (hereinafter, sometimes simply referred to as "DPC"), and 0.979 parts by mass of a 0.2 mass% aqueous solution of cesium carbonate as a catalyst were charged into a reaction vessel relative to 81.98 parts by mass of isosorbide (hereinafter, sometimes simply referred to as "ISB"), and the raw materials were dissolved with stirring (about 15 minutes) as the step of the 1 st stage of the reaction by heating the heating tank temperature to 150 ℃ in a nitrogen atmosphere. Subsequently, the pressure was set to 13.3kPa from the normal pressure, and the generated phenol was discharged to the outside of the reaction vessel while the temperature in the heating tank was increased to 190 ℃ over 1 hour. After the entire reaction vessel was maintained at 190 ℃ for 15 minutes, the pressure in the reaction vessel was set to 6.67kPa as the step of the 2 nd stage, the temperature in the heating tank was increased to 230 ℃ for 15 minutes, and the generated phenol was discharged to the outside of the reaction vessel. Since the stirring torque of the stirrer gradually increased, the pressure in the reaction vessel was set to 0.200kPa or less in order to raise the temperature to 250 ℃ in 8 minutes and further remove the generated phenol. When the stirring torque reached a predetermined value, the reaction was terminated, and the reaction product thus produced was extruded into water to obtain pellets of a polycarbonate copolymer. The obtained pellets were vacuum-dried at 80 ℃ for 5 hours, and then a resin film was produced using a film-forming apparatus equipped with a single-screw extruder (made by Toshiba mechanical Co., ltd., cylinder set temperature: 250 ℃), a T-die (width 200mm, set temperature: 250 ℃), a cooling roll (set temperature: 120 to 130 ℃) and a winder. The resulting long resin film was stretched in an oblique direction at a temperature of 135 ℃ at a stretch ratio of 2.2 times to obtain a polycarbonate resin film having a thickness of 40 μm.
[ example 2]
A polarizing plate was produced in the same manner as in example 1, except that the temperature of the aqueous boric acid solution in the underwater stretching treatment was 66 ℃, the immersion time in the aqueous boric acid solution was 60 seconds, and a cycloolefin film (17 μm, manufactured by ZEON corporation, japan) was used as the protective layer. The obtained polarizing plate was subjected to the same evaluation as in example 1. The results are shown in Table 1.
[ example 3]
A polarizing plate was produced in the same manner as in example 1, except that the temperature of the boric acid aqueous solution in the underwater stretching treatment was 64 ℃, the immersion time in the boric acid aqueous solution was 50 seconds, and an acrylic resin film (thickness: 40 μm) was used as a protective layer. The obtained polarizing plate was subjected to the same evaluation as in example 1. The results are shown in Table 1. The acrylic resin film was produced as follows. MS resin (copolymer of methyl methacrylate/styrene (molar ratio) = 80/20) was imidized with monomethylamine (imidization rate: 5%). The resulting imidized MS resin had glutarimide units, (meth) acrylate units and styrene units, and had an acid value of 0.5mmol/g. The obtained imidized MS resin was made into a film by melt extrusion molding. At this time, 0.66 parts by weight of the ultraviolet absorber was supplied per 100 parts by weight of the resin.
[ example 4]
In the same manner as in example 2, a polarizing material having a thickness of about 5 μm was formed on a resin substrate. A cycloolefin film (17 μm, manufactured by ZEON, japan) was bonded as a protective layer to the surface (the surface opposite to the resin substrate) of the obtained polarizer via an ultraviolet-curable adhesive. Specifically, the curable adhesive was applied so that the total thickness thereof became about 1.0 μm, and the coating was applied by a roll press. Thereafter, the adhesive is cured by irradiating UV light from the cycloolefin film side. Next, a polycarbonate resin film similar to that of example 1 was laminated on the surface of the polarizer exposed by peeling the resin base material in the same manner as described above. In this manner, a polarizing plate having a structure of a cycloolefin film (inner protective layer)/a polarizer/a polycarbonate resin film (outer protective layer) was obtained. The obtained polarizing plate was subjected to the same evaluation as in example 1. The results are shown in Table 1. The cycloolefin film was produced as follows. Pellets of a cycloolefin polymer (a hydrogenated product of a ring-opening polymer of a norbornene-based monomer, trade name "ZEONOR1420R", manufactured by ZEON, japan, having a glass transition temperature of 136 ℃) were prepared and dried at 100.5kPa and 100 ℃ for 12 hours. 1.5 parts by weight of a dye compound represented by the following formula was added to 100 parts by weight of the resin, and a film melt extrusion molding machine of T-mode was used at a die temperature of 260 ℃ in a one-way extruder to form an olefinic film.
[ example 5]
A polarizing plate having a structure of an acrylic resin film (inner protective layer)/polarizer/cycloolefin film (outer protective layer) was obtained in the same manner as in example 4, except that the same acrylic resin film as in example 3 was used as the inner protective layer and the same cycloolefin film as in example 4 was used as the outer protective layer. The obtained polarizing plate was subjected to the same evaluation as in example 1. The results are shown in Table 1.
[ example 6]
A polarizing plate was produced in the same manner as in example 5, except that the temperature of the aqueous boric acid solution in the underwater stretching treatment was 70 ℃ and the immersion time in the aqueous boric acid solution was 60 seconds. The obtained polarizing plate was subjected to the same evaluation as in example 1. The results are shown in Table 1.
Comparative example 1
A polarizing plate was produced in the same manner as in example 2, except that the temperature of the aqueous boric acid solution in the underwater stretching treatment was 70 ℃ and the immersion time was 50 seconds. The obtained polarizing plate was subjected to the same evaluation as in example 1. The results are shown in Table 1.
Comparative example 2
A polarizing material having a thickness of about 5 μm was formed on a resin base material in the same manner as in example 1, except that the temperature of the boric acid aqueous solution in the underwater stretching treatment was set to 70 ℃ and the immersion time was set to 50 seconds. A cycloolefin film (17 μm, manufactured by ZEON, japan) was bonded as a protective layer to the surface (the surface opposite to the resin substrate) of the obtained polarizer via an ultraviolet-curable adhesive. Specifically, the curable adhesive was applied so that the total thickness thereof became about 1.0 μm, and the coating was applied by a roll press. Thereafter, the adhesive is cured by irradiating UV light from the cycloolefin film side. Then, an acrylic film (40 μm, manufactured by Toyo Steel plate Co., ltd.) was bonded to the surface of the polarizer exposed by peeling off the resin substrate in the same manner as described above. In this manner, a polarizing plate having a structure of an acrylic film (inner protective layer)/polarizer/cycloolefin film (outer protective layer) was obtained. The obtained polarizing plate was subjected to the same evaluation as in example 1. The results are shown in Table 1.
[ Table 1]
As is clear from table 1, the polarizing plate according to the embodiment of the present invention has a small index of contrast of reflected image, and as a result, has a small aberration of transmitted wavefront. Therefore, it can be understood that the polarizing plate according to the embodiment of the present invention can realize an excellent image capturing function and a face authentication function without providing a through hole or a transparent portion when applied to an image display device having a camera portion. Such a polarizing plate can be realized by lowering the temperature of the boric acid aqueous solution and extending the immersion time in the underwater stretching treatment for producing the polarizer.
Industrial applicability
The polarizing plate according to the embodiment of the present invention is suitably used for an image display device (for example, a liquid crystal display device, an organic EL display device, and a quantum dot display device).
Description of the reference numerals
10 polarizer
20 st protective layer
30 nd 2 protective layer
100 polarizing plate
Claims (5)
1. A polarizing plate comprising a polarizer and a protective layer disposed on at least one side of the polarizer, wherein the polarizer is composed of a polyvinyl alcohol resin film containing a dichroic substance,
the polarizer has a reflection contrast index of 15 or less.
2. The polarizing plate of claim 1, wherein the polarizing element has a thickness of 12 μm or less.
3. The polarizing plate according to claim 2, wherein the reflective contrast index is 13 or less.
4. The polarizing plate according to any one of claims 1 to 3, wherein a protective layer is provided only on one side of the polarizing element.
5. An image display device is provided with: a display unit, and the polarizing plate according to any one of claims 1 to 4 disposed on at least one side of the display unit.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2020-080290 | 2020-04-30 | ||
| JP2020080290 | 2020-04-30 | ||
| PCT/JP2021/016161 WO2021220907A1 (en) | 2020-04-30 | 2021-04-21 | Polarizing plate, and image display device using polarizing plate |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115461659A true CN115461659A (en) | 2022-12-09 |
Family
ID=78373575
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202180031365.9A Pending CN115461659A (en) | 2020-04-30 | 2021-04-21 | Polarizing plate and image display device using the same |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JP7439246B2 (en) |
| KR (1) | KR20220150396A (en) |
| CN (1) | CN115461659A (en) |
| TW (1) | TW202146950A (en) |
| WO (1) | WO2021220907A1 (en) |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008164859A (en) * | 2006-12-27 | 2008-07-17 | Ricoh Co Ltd | Image producing engine and projection apparatus |
| JP2011085776A (en) * | 2009-10-16 | 2011-04-28 | Ricoh Co Ltd | Polarization separation device, optical scanning device, and image forming device |
| JP5011444B2 (en) | 2010-09-03 | 2012-08-29 | 日東電工株式会社 | Adhesive optical film, method for producing the same, and image display device |
| JP2012093723A (en) * | 2010-09-30 | 2012-05-17 | Fujifilm Corp | Optical film, polarizing plate, image display device and method for manufacturing optical film |
| JP6216497B2 (en) | 2011-05-30 | 2017-10-18 | 日東電工株式会社 | Polarizing plate with retardation layer |
| JP2014081482A (en) | 2012-10-16 | 2014-05-08 | Nitto Denko Corp | Polarizer and image display device |
| JP2013225150A (en) * | 2013-07-08 | 2013-10-31 | Fujifilm Corp | Optical film, production method of the same, polarizing plate and liquid crystal display device |
| JP6766472B2 (en) | 2015-06-30 | 2020-10-14 | 三菱ケミカル株式会社 | Laminated optical film and polarizing plate |
| JP6574731B2 (en) * | 2016-03-25 | 2019-09-11 | 富士フイルム株式会社 | Optical film, polarizing plate, and image display device |
| TWI743373B (en) * | 2017-09-13 | 2021-10-21 | 日商日東電工股份有限公司 | Polarizing film, polarizing plate, and manufacturing method of polarizing film |
| JP7027003B2 (en) | 2017-09-21 | 2022-03-01 | 日東電工株式会社 | Laminated optical film and its manufacturing method, and image display device |
| JP6609350B2 (en) * | 2018-06-13 | 2019-11-20 | 株式会社ポラテクノ | Imaging device using optical filter, head-up display, and optical filter manufacturing method |
-
2021
- 2021-04-21 JP JP2022517668A patent/JP7439246B2/en active Active
- 2021-04-21 WO PCT/JP2021/016161 patent/WO2021220907A1/en active Application Filing
- 2021-04-21 CN CN202180031365.9A patent/CN115461659A/en active Pending
- 2021-04-21 KR KR1020227036039A patent/KR20220150396A/en active Search and Examination
- 2021-04-26 TW TW110114987A patent/TW202146950A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| WO2021220907A1 (en) | 2021-11-04 |
| JP7439246B2 (en) | 2024-02-27 |
| TW202146950A (en) | 2021-12-16 |
| JPWO2021220907A1 (en) | 2021-11-04 |
| KR20220150396A (en) | 2022-11-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5740502B2 (en) | Method for producing optical film laminate roll having polarizing film | |
| JP5502023B2 (en) | Method for producing optical film laminate roll having polarizing film | |
| JP7355583B2 (en) | Polarizing plate with retardation layer and image display device using the same | |
| CN112840252B (en) | Polarizing plate with phase difference layer and image display device using same | |
| JP2023116527A (en) | Polarizer, method of manufacturing the same, and optical laminate comprising the same | |
| JP7355582B2 (en) | Polarizing plate with retardation layer and image display device using the same | |
| CN112840245B (en) | Polarizing plate with phase difference layer and image display device using same | |
| JP7280349B2 (en) | Polarizing film, polarizing plate, and method for producing the polarizing film | |
| CN112840250B (en) | Polarizing plate with retardation layer and image display device using the same | |
| CN115461659A (en) | Polarizing plate and image display device using the same | |
| WO2020080184A1 (en) | Polarizing plate having phase difference layer and image display device using same | |
| CN113646677B (en) | Polarizing film, polarizing plate, and method for producing polarizing film | |
| CN115989139B (en) | Polarizing plate, method for producing same, polarizing plate with retardation layer using same, and image display device | |
| CN115236785B (en) | Polarizing plate with phase difference layer and image display device using same | |
| CN116097332B (en) | Dyed cellulose triacetate film, polarizing plate using the same, method for producing polarizing plate, polarizing plate with retardation layer, image display device, and method for adjusting image of image display device | |
| WO2023218822A1 (en) | Method for producing polarizing film | |
| CN112840249B (en) | Polarizing plate with retardation layer and image display device using the same | |
| JP7355587B2 (en) | Polarizing plate with retardation layer and image display device using the same | |
| JP7355586B2 (en) | Polarizing plate with retardation layer and image display device using the same | |
| JP7355585B2 (en) | Polarizing plate with retardation layer and image display device using the same | |
| WO2023218821A1 (en) | Method for producing polarizing film | |
| WO2020080188A1 (en) | Polarizing plate with retardation layer and image display device using same | |
| WO2020080185A1 (en) | Polarizing plate with retardation layer and image display device using same | |
| WO2020080186A1 (en) | Polarizing plate with retardation layer and image display device using same | |
| WO2020080187A1 (en) | Polarizing plate with retardation layer and image display device using same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |