WO2018159569A1 - 液晶表示装置 - Google Patents
液晶表示装置 Download PDFInfo
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- WO2018159569A1 WO2018159569A1 PCT/JP2018/007090 JP2018007090W WO2018159569A1 WO 2018159569 A1 WO2018159569 A1 WO 2018159569A1 JP 2018007090 W JP2018007090 W JP 2018007090W WO 2018159569 A1 WO2018159569 A1 WO 2018159569A1
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- polyester film
- wavelength
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Classifications
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- 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
- G02B1/10—Optical coatings produced by application to, or surface treatment of, optical elements
- G02B1/11—Anti-reflection coatings
- G02B1/111—Anti-reflection coatings using layers comprising organic materials
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/30—Polarising elements
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- 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
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- 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 a polarizer protective film, a polarizing plate, and a liquid crystal display device. Specifically, the present invention relates to a liquid crystal display device in which generation of rainbow-like color spots is improved.
- a polarizing plate used in a liquid crystal display device is usually configured by sandwiching a polarizer obtained by dyeing iodine in polyvinyl alcohol (PVA) or the like between two polarizer protective films.
- PVA polyvinyl alcohol
- TAC triacetyl cellulose
- TAC films are very expensive, and polyester films have been proposed as inexpensive alternative materials (Patent Documents 1 to 3), but there is a problem that rainbow-like color spots occur.
- the polarization state of the linearly polarized light emitted from the backlight unit or the polarizer changes when passing through the polyester film.
- the transmitted light shows an interference color peculiar to retardation which is a product of birefringence and thickness of the oriented polyester film. Therefore, if a discontinuous emission spectrum such as a cold cathode tube or a hot cathode tube is used as the light source, the transmitted light intensity varies depending on the wavelength, resulting in a rainbow-like color spot (see: Proceedings of the 15th Micro Optical Conference Proceedings, No. 1) 30-31).
- a white light source having a continuous and broad emission spectrum such as a white light emitting diode as a backlight light source, and further using an oriented polyester film having a certain retardation as a polarizer protective film.
- Patent Document 4 White light emitting diodes have a continuous and broad emission spectrum in the visible light region. Therefore, focusing on the envelope shape of the interference color spectrum due to the transmitted light transmitted through the birefringent body, it becomes possible to obtain a spectrum similar to the emission spectrum of the light source by controlling the retardation of the oriented polyester film. It has become possible to suppress rainbow spots.
- the emission spectrum peaks in each wavelength region of blue region (400 nm to less than 495 nm), green region (495 nm to less than 600 nm) and red region (600 nm to 780 nm or less).
- White light-emitting diode for example, blue light-emitting diode and at least K 2 SiF 6 as a phosphor
- a liquid crystal display device using a backlight source composed of a white light emitting diode having a fluoride phosphor such as Mn 4+ has been developed.
- the transmission axis of the polarizer and the fast axis direction of the polyester film are usually arranged to be perpendicular to each other. Is done. This is because the polyvinyl alcohol film that is a polarizer is manufactured by longitudinal uniaxial stretching, and the polyester film that is the protective film is manufactured by longitudinal stretching and then lateral stretching, so that the polyester film orientation This is because the main axis direction is the horizontal direction, and when these long objects are bonded together to produce a polarizing plate, the fast axis of the polyester film and the transmission axis of the polarizer are usually perpendicular.
- an oriented polyester film having a specific retardation is used as the polyester film, and, for example, a white LED composed of a light emitting element in which a blue light emitting diode and a yttrium / aluminum / garnet yellow phosphor are combined is used as a backlight light source.
- a white LED composed of a light emitting element in which a blue light emitting diode and a yttrium / aluminum / garnet yellow phosphor are combined is used as a backlight light source.
- an object of the present invention is to have a peak top of an emission spectrum in each wavelength region of a blue region (400 nm or more and less than 495 nm), a green region (495 nm or more and less than 600 nm), and a red region (600 nm or more and 780 nm or less).
- a polyester film is used as a polarizer protective film in a liquid crystal display device having a backlight light source composed of a white light emitting diode having an emission spectrum having a relatively narrow half-width (less than 5 nm) in the region (600 nm or more and 780 nm or less).
- Another object is to provide a liquid crystal display device in which rainbow spots are suppressed.
- the representative present invention is as follows.
- Item 1 A liquid crystal display device having a backlight light source, two polarizing plates, and a liquid crystal cell disposed between the two polarizing plates,
- the backlight source has a peak top of the emission spectrum in each wavelength region of 400 nm to 495 nm, 495 nm to less than 600 nm, and 600 nm to 780 nm, and has the highest peak intensity in the wavelength region of 600 nm to 780 nm.
- a white light-emitting diode having an emission spectrum with a peak half-width less than 5 nm, At least one polarizing plate among the polarizing plates is obtained by laminating a polyester film on at least one surface of a polarizer, The polyester film has a retardation of 1500 nm or more and 30000 nm or less, An antireflection layer and / or a low reflection layer is laminated on one surface of the polyester film, The polyester film laminated with the antireflection layer and / or the low reflection layer has a reflection spectrum measured from the side where the antireflection layer and / or the low reflection layer is laminated, having a bottom wavelength in a wavelength region of 600 nm to 780 nm.
- the emission spectrum of the backlight source is The full width at half maximum of the peak with the highest peak intensity in the wavelength region of 400 nm or more and less than 495 nm is 5 nm or more, The full width at half maximum of the peak with the highest peak intensity in the wavelength region of 495 nm or more and less than 600 nm is 5 nm or more, Item 2.
- a polarizer protective film in which an antireflection layer and / or a low reflection layer is laminated on one surface of a polyester film The polyester film has a retardation of 1500 nm or more and 30000 nm or less, The polyester film laminated with the antireflection layer and / or the low reflection layer has a reflection spectrum measured from the side where the antireflection layer and / or the low reflection layer is laminated, having a bottom wavelength in a wavelength region of 600 nm to 780 nm.
- the liquid crystal display device, polarizing plate, and polarizer protective film of the present invention can ensure good visibility in which the occurrence of rainbow-like color spots is significantly suppressed at any observation angle.
- a liquid crystal display device includes a rear module, a liquid crystal cell, and a front module in order from the backlight light source side to the image display side (viewing side).
- the rear module and the front module are generally composed of a transparent substrate, a transparent conductive film formed on the liquid crystal cell side surface, and a polarizing plate disposed on the opposite side.
- the polarizing plate is disposed on the backlight source side in the rear module, and is disposed on the image display side (viewing side) in the front module.
- the liquid crystal display device of the present invention includes at least a backlight light source and a liquid crystal cell disposed between two polarizing plates.
- the liquid crystal display device may appropriately have other components in addition to the backlight source, the polarizing plate, and the liquid crystal cell, such as a color filter, a lens film, a diffusion sheet, and an antireflection film.
- a brightness enhancement film may be provided between the light source side polarizing plate and the backlight light source.
- the brightness enhancement film include a reflective polarizing plate that transmits one linearly polarized light and reflects linearly polarized light orthogonal thereto.
- the reflective polarizing plate for example, a DBEF (Dual Brightness Enhancement Film) series brightness enhancement film manufactured by Sumitomo 3M Limited is preferably used.
- the reflective polarizing plate is usually arranged so that the absorption axis of the reflective polarizing plate and the absorption axis of the light source side polarizing plate are parallel to each other.
- At least one polarizing plate has a polyester film laminated on at least one surface of a polarizer in which iodine is dyed on polyvinyl alcohol (PVA) or the like. It is.
- the polyester film has a specific retardation, and an antireflection layer and / or a low reflection layer is laminated on at least one surface of the polyester film. is there.
- the antireflection layer and / or the low reflection layer may be provided on the surface opposite to the surface on which the polarizer of the polyester film is laminated, or on the surface on which the polarizer of the polyester film is laminated, Both are acceptable.
- the refractive index of the polyester film in the direction parallel to the transmission axis of the polarizer is preferably 1.53 to 1.62.
- a film having substantially no birefringence (low retardation) as typified by a TAC film, an acrylic film, or a norbornene-based film is laminated (with a three-layer structure).
- a polarizing plate a film is not necessarily laminated on the other surface of the polarizer (a polarizing plate having a two-layer structure).
- the slow axes of both polyester films are substantially parallel to each other.
- substantially parallel means that the angle formed by the two axes is ⁇ 15 ° to 15 °, preferably ⁇ 10 ° to 10 °, more preferably ⁇ 5 ° to 5 °, and still more preferably ⁇ 3 ° to It means 3 °, more preferably ⁇ 2 ° to 2 °, and still more preferably ⁇ 1 ° to 1 °.
- any polarizer (polarizing film) used in the technical field can be appropriately selected and used.
- typical polarizers include those obtained by dyeing a dichroic material such as iodine on a polyvinyl alcohol film or the like.
- the polarizer is not limited to this, and may be a known and later-developed polarizer. Can be appropriately selected and used.
- the dichroic material includes iodine, a diazo compound, a polymethine dye, and the like.
- the polarizer can be obtained by any method.
- a PVA film dyed with a dichroic material is uniaxially stretched in an aqueous boric acid solution, and washed and dried while maintaining the stretched state.
- the stretching ratio of uniaxial stretching is usually about 4 to 8 times, but is not particularly limited. Other manufacturing conditions and the like can be appropriately set according to known methods.
- the configuration of the backlight may be an edge light method using a light guide plate, a reflection plate, or the like, or a direct type, but in the present invention, as a backlight light source of a liquid crystal display device, 400 nm or more, less than 495 nm, 495 nm or more, less than 600 nm, and 600 nm or more and 750 nm or less, each having a peak top of the emission spectrum, and the half width of the peak with the highest peak intensity in the wavelength region of 600 nm or more and 780 nm or less
- a backlight light source consisting of a white light emitting diode having an emission spectrum of less than 5 nm is preferred.
- the upper limit of the full width at half maximum of the peak having the highest peak intensity in the wavelength region of 600 nm or more and 780 nm or less is preferably less than 5 nm, more preferably less than 4 nm, and still more preferably less than 3.5 nm.
- the lower limit is preferably 1 nm or more, and more preferably 1.5 nm or more. It is preferable that the half width of the peak is less than 5 nm because the color gamut of the liquid crystal display device is widened. In addition, there is no lower limit of the half width of the peak, but it can be set to 1 nm. If the peak half width is less than 1 nm, the light emission efficiency may deteriorate.
- the shape of the emission spectrum is designed from the balance between the required color gamut and the luminous efficiency.
- the half width is the peak width (nm) at half the intensity of the peak intensity at the peak top wavelength.
- a backlight light source having an emission spectrum having the above-described characteristics is a technology that has been attracting attention due to the recent increasing demand for color gamut expansion.
- Conventionally used white LEDs for example, light-emitting elements that combine blue light-emitting diodes with yttrium, aluminum, and garnet yellow phosphors
- white LEDs for example, light-emitting elements that combine blue light-emitting diodes with yttrium, aluminum, and garnet yellow phosphors
- backlight light sources have a spectrum that can be recognized by the human eye. Only about 20% of colors can be reproduced.
- a backlight light source having an emission spectrum having the above-described characteristics it is said that it is possible to reproduce 60% or more of colors.
- the wavelength region of 400 nm or more and less than 495 nm is more preferably 430 nm or more and 470 nm or less.
- the wavelength region of 495 nm or more and less than 600 nm is more preferably 510 nm or more and 560 nm or less.
- the wavelength region of 600 nm to 780 nm is more preferably 600 nm to 700 nm, even more preferably 610 nm to 680 nm, and even more preferably 610 nm to 660 nm.
- the peak half-width at the peak top of each wavelength region of the emission spectrum from 400 nm to less than 495 nm and from 495 nm to less than 600 nm is not particularly limited, but is from 400 nm to less than 495 nm
- the half-width of the peak having the highest peak intensity in the wavelength region is preferably 5 nm or more, and the half-width of the peak having the highest peak intensity in the wavelength region of from 495 nm to less than 600 nm is preferably 5 nm or more.
- the upper limit of the peak half width at the peak top of each wavelength region from 400 nm to less than 495 nm and from 495 nm to less than 600 nm is Preferably it is 140 nm or less, Preferably it is 120 nm or less, Preferably it is 100 nm or less, More preferably, it is 80 nm or less, More preferably, it is 60 nm or less, More preferably, it is 50 nm or less.
- a white light source having an emission spectrum having the above-described characteristics include a phosphor type white light emitting diode in which a blue light emitting diode and a phosphor are combined.
- the red phosphor among the phosphors include a fluoride phosphor (also referred to as “KSF”) whose composition formula is K 2 SiF 6 : Mn 4+ , and others.
- the Mn 4+ activated fluoride complex phosphor is a phosphor having Mn 4+ as an activator, a fluoride complex salt of an alkali metal, amine, or alkaline earth metal as a base crystal.
- Fluoride complexes that form host crystals include those whose coordination center is a trivalent metal (B, Al, Ga, In, Y, Sc, lanthanoid), and tetravalent metal (Si, Ge, Sn, Ti, Zr, Re, Hf) and pentavalent metals (V, P, Nb, Ta), and the number of fluorine atoms coordinated around them is 5-7.
- Mn 4+ activated fluoride complex phosphor examples include A 2 [MF 6 ]: Mn (A is one or more selected from Li, Na, K, Rb, Cs, and NH 4 ; M is Ge, Si , Sn, Ti, and Zr), E [MF 6 ]: Mn (E is one or more selected from Mg, Ca, Sr, Ba, and Zn; M is Ge, Si, Sn, Ti, And at least one selected from Zr), Ba 0.65 , Zr 0.35 F 2.70 : Mn, A 3 [ZrF 7 ]: Mn (A is Li, Na, K, Rb, Cs, and NH 4.
- Mn 4+ activated fluoride complex phosphors is A 2 MF 6 : Mn (A is selected from Li, Na, K, Rb, Cs, and NH 4) whose base crystal is a hexafluoro complex salt of an alkali metal.
- M is one or more selected from Ge, Si, Sn, Ti, and Zr).
- A is preferably one or more selected from K (potassium) and Na (sodium), and M is Si (silicon) or Ti (titanium).
- A is K (the ratio of K in the total amount of A is 99 mol% or more) and M is Si.
- the activation element is preferably 100% Mn (manganese), but Ti, Zr, Ge, Sn, Al, Ga, B, In, Cr, in a range of less than 10 mol% with respect to the total amount of the activation element. Fe, Co, Ni, Cu, Nb, Mo, Ru, Ag, Zn, Mg, and the like may be included.
- M is Si
- the ratio of Mn in the total of Si and Mn is preferably in the range of 0.5 mol% to 10 mol%.
- Mn 4+ activated fluoride complex phosphors have the chemical formula A 2 + x M y Mn z F n (A is Na and K; M is Si and Al; ⁇ 1 ⁇ x ⁇ 1 and 0.9 ⁇ y + z ⁇ 1) .1 and 0.001 ⁇ z ⁇ 0.4 and 5 ⁇ n ⁇ 7).
- the backlight light source is preferably a white light emitting diode having a blue light emitting diode and at least a fluoride phosphor as a phosphor, and particularly preferably a fluoride having at least K 2 SiF 6 : Mn 4+ as a blue light emitting diode and a phosphor.
- a white light emitting diode having a phosphor For example, commercially available products such as NSSW306FT, which is a white LED manufactured by Nichia Corporation, can be used.
- the green phosphor for example, a sialon phosphor having a basic composition of ⁇ -SiAlON: Eu or the like, or a silicate phosphor having a basic composition of (Ba, Sr) 2 SiO 4 : Eu or the like. Others are exemplified.
- the wavelength region of 495 nm or more and less than 600 nm, or the wavelength region of 600 nm or more and 780 nm or less the following is considered.
- the half width of the peak with the highest peak intensity is in the above range.
- the half-value width is similarly in the above range for other peaks having an intensity of 70% or more of the highest peak intensity.
- the half width of the peak having the highest peak intensity among the plurality of peaks can be used as it is.
- the independent peak has an intensity region that is 1 ⁇ 2 of the peak intensity on both the short wavelength side and the long wavelength side of the peak. That is, when a plurality of peaks overlap and each peak does not have a region having an intensity that is 1 ⁇ 2 of the peak intensity on both sides thereof, the plurality of peaks are regarded as one peak as a whole.
- the peak width (nm) at half the intensity of the highest peak intensity is set as the half width.
- the point with the highest peak intensity is defined as the peak top.
- the peak having the highest peak intensity in each of the wavelength region of 400 nm or more and less than 495 nm, the wavelength region of 495 nm or more and less than 600 nm, or the wavelength region of 600 nm or more and 780 nm or less is independent from the peaks of other wavelength regions. It is preferable that the relationship is In particular, the wavelength region between the peak having the highest peak intensity in the wavelength region of 495 nm or more and less than 600 nm and the peak having the highest peak intensity in the region of 600 nm or more and 780 nm or less has a wavelength of 600 nm or more and 780 nm or less. It is preferable in terms of color clarity that there is a region that is 1/3 or less of the peak intensity of the peak having the highest peak intensity in the region.
- the emission spectrum of the backlight light source can be measured by using a spectroscope such as Hamamatsu Photonics multi-channel spectroscope PMA-12.
- each wavelength region of the blue region 400 nm to less than 495 nm
- the green region (495 nm to less than 600 nm)
- the red region 600 nm to 780 nm or less
- a polyester film having retardation and having a specific antireflection layer and / or a low reflection layer laminated thereon is used, it is effective for suppressing rainbow spots.
- the polyester film on which the specific antireflection layer and / or the low reflection layer is laminated has a bottom wavelength of the reflection spectrum at 600 nm or more and 780 nm or less, and the reflectance at the bottom wavelength is 2% or less.
- the reflection spectrum is obtained by measuring the reflection spectrum of the polyester film on which the antireflection layer and / or the low reflection layer are laminated from the side on which the antireflection layer and / or the low reflection layer is laminated.
- the bottom wavelength of the reflection spectrum is a wavelength at which the reflectance is minimum in the reflection spectrum of 400 nm to 780 nm.
- the bottom wavelength of the reflection spectrum is preferably in the wavelength region of 600 nm to 780 nm, more preferably 600 nm to 700 nm, even more preferably 610 nm to 680 nm, and even more preferably 610 nm to 660 nm. It is as follows.
- the polarization state of the linearly polarized light emitted from the backlight unit or the polarizer changes when passing through the polyester film.
- One of the factors that change the polarization state may be the influence of the refractive index difference at the interface between the air layer and the oriented polyester film or the refractive index difference at the interface between the polarizer and the oriented polyester film.
- the light passing through the polarizer and entering the oriented polyester film is linearly polarized light, and it is considered that there is no transmittance dependency on the wavelength in the state of linearly polarized light.
- Incident light of linearly polarized light changes to elliptically polarized light or circularly polarized light by passing through the oriented polyester film.
- the transmittance in a wavelength band with a large amount of S-polarized light component is reduced, which is considered to be one of the factors that cause rainbow-like color spots.
- the transmittance change due to wavelength is large.
- interface reflection at an arbitrary wavelength can be suppressed. Therefore, by forming an antireflection layer and / or a low reflection layer having a bottom wavelength in the red region (600 nm or more and 780 nm or less), the transmittance of the red region is formed.
- each wavelength region of the blue region (400 nm or more and less than 495 nm), the green region (495 nm or more and less than 600 nm), and the red region (600 nm or more and 780 nm or less) has an emission spectrum peak top.
- a liquid crystal display device having a backlight light source composed of a white light emitting diode having a relatively narrow half-width of a peak in a region (600 nm or more and 780 nm or less) even if a polarizing plate using a polyester film is used as a polarizer protective film, It is possible to have good visibility without causing color spots.
- a polarizer protective film made of a polyester film is laminated on at least one surface of the polarizer.
- the polyester film used for the polarizer protective film preferably has a retardation of 1500 nm or more and 30000 nm or less. If the retardation is in the above range, it is preferable because rainbow spots tend to be reduced more easily.
- a preferable lower limit of retardation is 3000 nm, a next preferable lower limit is 3500 nm, a more preferable lower limit is 4000 nm or 5000 nm, a still more preferable lower limit is 6000 nm, and a still more preferable lower limit is 8000 nm.
- a preferable upper limit is 30000 nm, and a polyester film having a retardation larger than this has a considerably large thickness and tends to deteriorate the handleability as an industrial material.
- a more preferable upper limit is 15000 nm, still more preferably 12000 nm, and still more preferably 11000 nm.
- the retardation of the present invention can be obtained by measuring the refractive index and thickness in the biaxial direction, or by using a commercially available automatic birefringence measuring device such as KOBRA-21ADH (Oji Scientific Instruments). it can.
- the refractive index can be obtained by an Abbe refractometer (measurement wavelength: 589 nm).
- the ratio (Re / Rth) of the retardation of the polyester film (Re: in-plane retardation) to the retardation in the thickness direction (Rth) is preferably 0.2 or more, more preferably 0.5 or more, and still more preferably 0.8. 6 or more.
- the ratio of the retardation to the retardation in the thickness direction (Re / Rth) is larger, the birefringence action is more isotropic, and the occurrence of rainbow-like color spots depending on the observation angle tends to be less likely to occur.
- the ratio of the retardation to the retardation in the thickness direction (Re / Rth) is 2.0.
- the ratio of the retardation to the retardation in the thickness direction (Re / Rth)
- the upper limit is preferably 2.0.
- the thickness direction retardation means an average of retardation obtained by multiplying two birefringences ⁇ Nxz and ⁇ Nyz by the film thickness d when the film is viewed from the cross section in the thickness direction.
- the polyester film preferably has an NZ coefficient of 2.5 or less, more preferably 2.0 or less, still more preferably 1.8 or less, and still more preferably 1. 6 or less. And since a NZ coefficient will be 1.0 in a perfect uniaxial (uniaxial symmetry) film, the minimum of a NZ coefficient is 1.0. However, it should be noted that the mechanical strength in the direction perpendicular to the orientation direction tends to decrease significantly as the film approaches a perfect uniaxial (uniaxial symmetry) film.
- the NZ coefficient is represented by
- the orientation axis of the film is obtained using a molecular orientation meter (MOA-6004 type molecular orientation meter, manufactured by Oji Scientific Instruments Co., Ltd.), and the biaxial refractive index (Ny, Nx, where the orientation axis direction and the direction perpendicular thereto are perpendicular) Ny> Nx) and the refractive index (Nz) in the thickness direction are determined by Abbe's refractometer (manufactured by Atago Co., Ltd., NAR-4T, measurement wavelength 589 nm). The value obtained in this manner can be substituted for
- the Ny-Nx value of the polyester film is preferably 0.05 or more, more preferably 0.07 or more, further preferably 0.08 or more, and still more preferably. Is 0.09 or more, most preferably 0.1 or more.
- the upper limit is not particularly defined, but in the case of a polyethylene terephthalate film, the upper limit is preferably about 1.5.
- the refractive index of the polyester film in the direction parallel to the transmission axis direction of the polarizer constituting the polarizing plate is preferably in the range of 1.53 to 1.62.
- it is possible to suppress reflection at the interface between the polarizer and the polyester film and to suppress iridescent color spots.
- it is 1.61 or less, More preferably, it is 1.60 or less, More preferably, it is 1.59 or less, More preferably, it is 1.58 or less.
- the lower limit of the refractive index is preferably 1.53.
- the refractive index is less than 1.53, crystallization of the polyester film becomes insufficient, and properties obtained by stretching such as dimensional stability, mechanical strength, and chemical resistance become insufficient.
- it is 1.56 or more, More preferably, it is 1.57 or more.
- the polarizing plate In order to set the refractive index of the polyester film in the direction parallel to the transmission axis direction of the polarizer in the range of 1.53 or more and 1.62 or less, the polarizing plate has the transmission axis of the polarizer and the fast axis of the polyester film. It is preferable that (the slow axis and the vertical method) are substantially parallel.
- the refractive index in the fast axis direction which is the direction perpendicular to the slow axis, can be adjusted to a low value of about 1.53 to 1.62 by stretching the polyester film in the film forming process described later.
- the refractive index of the polyester film in the direction parallel to the transmission axis direction of the polarizer is set to 1.53 to 1.62.
- substantially parallel means that the angle formed by the transmission axis of the polarizer and the fast axis of the polarizer protective film is ⁇ 15 ° to 15 °, preferably ⁇ 10 ° to 10 °, more preferably ⁇ 5 °. It means -5 °, more preferably -3 ° to 3 °, still more preferably -2 ° to 2 °, and still more preferably -1 ° to 1 °.
- substantially parallel is substantially parallel.
- “substantially parallel” means that the transmission axis and the fast axis are parallel to such an extent that a deviation inevitably generated when the polarizer and the protective film are bonded to each other is allowed.
- the direction of the slow axis can be determined by measuring with a molecular orientation meter (for example, MOA-6004 type molecular orientation meter manufactured by Oji Scientific Instruments).
- the refractive index in the fast axis direction of the polyester film is preferably 1.53 or more and 1.62 or less.
- the refractive index of the polyester film in the direction parallel to the transmission axis of the child can be 1.53 or more and 1.62 or less.
- the polarizer protective film comprising the polyester film used in the present invention can be used for both the incident light side (light source side) and the outgoing light side (viewing side) polarizing plates, but at least the outgoing light side (viewing side). It is preferable to use for the protective film of this polarizing plate.
- the polarizer protective film made of the above polyester film is arranged on both sides, whether it is arranged on the liquid crystal side starting from the polarizer or on the outgoing light side. It may be arranged, but it is preferable that it is arranged at least on the outgoing light side.
- the polarizer protective film made of the polyester film may be disposed on the incident light side from the polarizer, or on the liquid crystal cell side. However, it is preferable that it is disposed at least on the incident light side.
- the polarizing plate arranged on the incident light side does not use a polarizer protective film made of a polyester film, but uses a polarizer protective film that is substantially free of birefringence (low retardation) such as a triacetyl cellulose film. It may be what you did.
- Polyester used for the polyester film may be polyethylene terephthalate or polyethylene naphthalate, but may contain other copolymerization components. These resins are excellent in transparency and excellent in thermal and mechanical properties, and the retardation can be easily controlled by stretching.
- polyethylene terephthalate has a large intrinsic birefringence, and by stretching the film, the refractive index in the fast axis direction (perpendicular to the slow axis direction) can be kept low, and even if the film is thin, It is the most suitable material because a large retardation can be easily obtained.
- the polyester film preferably has a light transmittance of 20% or less at a wavelength of 380 nm.
- the light transmittance at 380 nm is more preferably 15% or less, further preferably 10% or less, and particularly preferably 5% or less. If the light transmittance is 20% or less, the optical functional dye can be prevented from being deteriorated by ultraviolet rays.
- the transmittance is measured by a method perpendicular to the plane of the film, and can be measured using a spectrophotometer (for example, Hitachi U-3500 type).
- the ultraviolet absorber used in the present invention is a known substance.
- the ultraviolet absorber include an organic ultraviolet absorber and an inorganic ultraviolet absorber, and an organic ultraviolet absorber is preferable from the viewpoint of transparency.
- the organic ultraviolet absorber include benzotriazole, benzophenone, cyclic imino ester, and combinations thereof, but are not particularly limited as long as the absorbance is within the range defined by the present invention. From the viewpoint of durability, benzotriazole and cyclic imino ester are particularly preferable.
- ultraviolet rays having different wavelengths can be absorbed simultaneously, so that the ultraviolet absorption effect can be further improved.
- benzophenone ultraviolet absorbers examples include 2- [2'-hydroxy-5 '-(methacryloyloxymethyl) phenyl] -2H-benzotriazole, 2- [2' -Hydroxy-5 '-(methacryloyloxyethyl) phenyl] -2H-benzotriazole, 2- [2'-hydroxy-5'-(methacryloyloxypropyl) phenyl] -2H-benzotriazole, 2,2'-dihydroxy- 4,4′-dimethoxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone, 2,4-di-tert-butyl-6- (5-chlorobenzotriazol-2-yl) phenol, 2- ( 2'-hydroxy-3'-tert-butyl-5 -Methylphenyl) -5-chlorobenzotriazole, 2- (5-
- cyclic imino ester UV absorbers examples include 2,2 ′-(1 , 4-phenylene) bis (4H-3,1-benzoxazinon-4-one), 2-methyl-3,1-benzoxazin-4-one, 2-butyl-3,1-benzoxazine-4-one ON, 2-phenyl-3,1-benzoxazin-4-one, etc. However, it is not particularly limited thereto.
- additives include inorganic particles, heat resistant polymer particles, alkali metal compounds, alkaline earth metal compounds, phosphorus compounds, antistatic agents, light proofing agents, flame retardants, thermal stabilizers, antioxidants, and antigelling agents. And surfactants.
- a polyester film does not contain a particle
- “Substantially free of particles” means, for example, in the case of inorganic particles, a content that is 50 ppm or less, preferably 10 ppm or less, particularly preferably the detection limit or less when inorganic elements are quantified by fluorescent X-ray analysis. means.
- the reflection spectrum of the polyester film laminated with the antireflection layer and / or the low reflection layer has a bottom wavelength in a wavelength region of 600 nm or more and 780 nm or less, and a reflectance at the bottom wavelength is 2% or less. .
- This reflection spectrum is measured from the side where the antireflection layer and / or the low reflection layer is laminated.
- the bottom wavelength of the reflection spectrum is a wavelength at which the reflectance is minimum in the reflection spectrum of 400 nm to 780 nm.
- the reflectance at the bottom wavelength of the antireflection layer and / or the low reflection layer used in the present invention is preferably 2% or less. If it exceeds 2%, rainbow-like color spots are likely to be visually recognized, which is not preferable.
- the reflectance is more preferably less than 2%, more preferably 1.6% or less, still more preferably 1.2% or less, and particularly preferably 1% or less. Although the minimum of a reflectance is not specifically limited, For example, it is 0.01%. A reflectance of 0% is most preferable.
- the upper limit of the reflectance is preferably less than 1%.
- the upper limit of the reflectance is preferably 2% or less, more preferably less than 2%, and the lower limit is preferably about 1%.
- the reflectance can be measured by the method described in Examples described later.
- the antireflection layer may be a single layer or a multilayer.
- the thickness of the low refractive index layer made of a material having a lower refractive index than that of the polyester film is set to 1/4 wavelength of the light wavelength or its thickness. If it is formed to be an odd multiple, an antireflection effect can be obtained.
- the antireflection layer is a multilayer, an antireflection effect can be obtained by alternately laminating two or more low refractive index layers and high refractive index layers and controlling the thickness of each layer as appropriate.
- a hard coat layer can be laminated between the antireflection layers, and an antifouling layer can be formed on the hard coat layer.
- Other antireflection layers include those using a moth-eye structure.
- the moth-eye structure is a concavo-convex structure with a pitch smaller than the wavelength formed on the surface. With this structure, a sudden and discontinuous refractive index change at the boundary with air is changed into a continuous and gradually changing refractive index change. It is possible to change. Thereby, the light reflection in the surface of a film reduces by forming a moth eye structure in the surface.
- JP 2001-517319 A can be referred to.
- a dry coating method in which an antireflection layer is formed on the surface of the substrate by vapor deposition or sputtering, and an antireflection layer is formed by applying an antireflection coating solution on the surface of the substrate and drying it.
- the composition of the antireflection layer and the formation method thereof are not particularly limited as long as the above characteristics are satisfied.
- a conventionally known low reflection layer can be used.
- it is formed by a method of laminating at least one metal or oxide thin film by vapor deposition or sputtering, a method of coating one or more organic thin films, or the like.
- a polyester film or an organic thin film having a lower refractive index than that of a hard coat layer laminated on the polyester film is preferably used.
- the formula 2nd ⁇ b / 4 is obtained.
- n is the refractive index of the antireflection layer or the refractive index of the low reflection layer
- d is the thickness of the antireflection layer or the thickness of the low reflection layer
- ⁇ b is the bottom wavelength of the reflection spectrum.
- the following calculation can be made from the principle of thin film interference.
- five layers a first layer, a second layer, a third layer, a fourth layer, and a fifth layer configuration.
- An incident medium layer (in) on the side of the first layer opposite to the side in contact with the second layer)
- the refractive index is n
- the reflectance is r
- the thickness is Is d
- the refraction angle is ⁇
- the wavelength is ⁇
- the phase difference is ⁇
- the reflectance of the lowermost layer is expressed by the following equation from the equation of thin film interference.
- the subscript numbers indicate each layer. Further, consecutive suffix numbers indicate the reflectivity between layers.
- Delta x becomes a phase difference when the a thin film of each layer x back and forth in a V-shape in refraction angle theta x, it is calculated by the formula of [Expression 2].
- ⁇ x is calculated by the formula [Equation 3] by using Snell's law continuously.
- the reflectance of each layer can be obtained from the following equation. (5th to 4th layers)
- the bottom wavelength can be designed to the target wavelength by adjusting the refractive index n and thickness d of each layer from the above equation.
- the peak top wavelength ⁇ p of the peak with the highest peak intensity in the wavelength range of 600 nm to 780 nm and the bottom wavelength ⁇ b of the reflection spectrum have an absolute value of the difference between ⁇ p and ⁇ b of 30 nm. Or less, preferably 20 nm or less, preferably 10 nm or less, and preferably 5 nm or less.
- the antireflection layer and / or the low reflection layer may be further provided with an antiglare function. Thereby, it is possible to further suppress rainbow spots. That is, a combination of an antireflection layer and an antiglare layer, a combination of a low reflection layer and an antiglare layer, or a combination of an antireflection layer, a low reflection layer and an antiglare layer may be used. Particularly preferred is a combination of a low reflection layer and an antiglare layer.
- the antiglare layer a conventionally known antiglare layer can be used. For example, from the viewpoint of suppressing surface reflection of the film, an embodiment in which an antiglare layer is laminated on a polyester film and then an antireflection layer or a low reflection layer is laminated is preferable.
- the polyester film preferably has an easy adhesion layer on the surface thereof.
- the refractive index of the easy-adhesion layer can be adjusted by a known method.
- the refractive index of the easy-adhesion layer can be easily adjusted by containing a binder resin with titanium, germanium, or other metal species.
- the polyester film can be subjected to corona treatment, coating treatment, flame treatment, etc. in order to improve the adhesion with the polarizer.
- At least one surface of the film of the present invention has an easy-adhesion layer mainly composed of at least one of a polyester resin, a polyurethane resin or a polyacrylic resin.
- the “main component” refers to a component that is 50% by mass or more of the solid components constituting the easy-adhesion layer.
- the coating solution used for forming the easy-adhesion layer of the present invention is preferably an aqueous coating solution containing at least one of water-soluble or water-dispersible copolymerized polyester resin, acrylic resin, and polyurethane resin.
- coating solutions include water-soluble or water-dispersible co-polymers disclosed in Japanese Patent No. 3567927, Japanese Patent No. 3589232, Japanese Patent No. 3589233, Japanese Patent No. 3900191, and Japanese Patent No. 4150982.
- coating solutions include a polymerized polyester resin solution, an acrylic resin solution, and a polyurethane resin solution.
- the easy-adhesion layer can be obtained by applying the coating solution on one or both sides of an unstretched film or a uniaxially stretched film in the longitudinal direction, drying at 100 to 150 ° C., and further stretching in the transverse direction.
- the final coating amount of the easy adhesion layer is preferably controlled to 0.05 to 0.2 g / m 2 . If the coating amount is less than 0.05 g / m 2 , the adhesion with the resulting polarizer may be insufficient. On the other hand, when the coating amount exceeds 0.2 g / m 2 , blocking resistance may be lowered.
- the application quantity of an easily bonding layer on both surfaces may be the same or different, and can be independently set within the above range.
- particles it is preferable to add particles to the easy-adhesion layer in order to impart slipperiness. It is preferable to use particles having an average particle size of 2 ⁇ m or less. When the average particle diameter of the particles exceeds 2 ⁇ m, the particles easily fall off from the coating layer.
- particles to be included in the easy adhesion layer for example, titanium oxide, barium sulfate, calcium carbonate, calcium sulfate, silica, alumina, talc, kaolin, clay, calcium phosphate, mica, hectorite, zirconia, tungsten oxide, lithium fluoride,
- examples include inorganic particles such as calcium fluoride, and organic polymer particles such as styrene, acrylic, melamine, benzoguanamine, and silicone. These may be added alone to the easy-adhesion layer, or may be added in combination of two or more.
- a known method can be used as a method for applying the coating solution.
- reverse roll coating method gravure coating method, kiss coating method, roll brush method, spray coating method, air knife coating method, wire bar coating method, pipe doctor method, etc.
- spray coating method air knife coating method, wire bar coating method, pipe doctor method, etc.
- wire bar coating method wire bar coating method
- pipe doctor method etc.
- the average particle size of the above particles is measured by the following method. Take a picture of the particles with a scanning electron microscope (SEM) and at a magnification such that the size of one smallest particle is 2-5 mm, the maximum diameter of 300-500 particles (between the two most distant points) Distance) is measured, and the average value is taken as the average particle diameter.
- SEM scanning electron microscope
- the polyester film used as a polarizer protective film can be manufactured according to a general polyester film manufacturing method.
- the polyester resin is melted and the non-oriented polyester extruded and formed into a sheet shape is stretched in the longitudinal direction by utilizing the speed difference of the roll at a temperature equal to or higher than the glass transition temperature, and then stretched in the transverse direction by a tenter.
- the method of performing heat processing is mentioned.
- the polyester film used in the present invention may be a uniaxially stretched film or a biaxially stretched film, but when the biaxially stretched film is used as a polarizer protective film, it is observed from directly above the film surface. However, rainbow-like color spots are not seen, but care must be taken because rainbow-like color spots may be observed when observed from an oblique direction.
- the longitudinal stretching temperature and the transverse stretching temperature are preferably 80 to 130 ° C, particularly preferably 90 to 120 ° C.
- the longitudinal draw ratio is preferably 1.0 to 3.5 times, particularly preferably 1.0 to 3.0 times.
- the transverse draw ratio is preferably 2.5 to 6.0 times, and particularly preferably 3.0 to 5.5 times.
- the longitudinal draw ratio is preferably 2.5 to 6.0 times, particularly preferably 3.0 to 5.5 times.
- the transverse draw ratio is preferably 1.0 to 3.5 times, and particularly preferably 1.0 to 3.0 times.
- the treatment temperature is preferably from 100 to 250 ° C., particularly preferably from 180 to 245 ° C.
- the thickness unevenness of the film is small. Since the stretching temperature and the stretching ratio have a great influence on the thickness unevenness of the film, it is preferable to optimize the film forming conditions from the viewpoint of the thickness unevenness. In particular, if the longitudinal stretching ratio is lowered to increase the retardation, the longitudinal thickness unevenness may be deteriorated. Since there is a region where the vertical thickness unevenness becomes very bad in a specific range of the draw ratio, it is desirable to set the film forming conditions outside this range.
- the thickness unevenness of the polyester film is preferably 5% or less, more preferably 4.5% or less, still more preferably 4% or less, and particularly preferably 3% or less.
- the stretching ratio, stretching temperature, and film thickness can be appropriately set.
- the higher the stretching ratio, the lower the stretching temperature, and the thicker the film the higher the retardation.
- the lower the stretching ratio, the higher the stretching temperature, and the thinner the film the lower the retardation.
- the thickness of the polyester film is arbitrary, but is preferably in the range of 15 to 300 ⁇ m, more preferably in the range of 15 to 200 ⁇ m. Even in the case of a film having a thickness of less than 15 ⁇ m, it is possible in principle to obtain a retardation of 1500 nm or more. However, in that case, the anisotropy of the mechanical properties of the film becomes remarkable, and it becomes easy to cause tearing, tearing, etc., and the practicality as an industrial material is remarkably lowered. A particularly preferable lower limit of the thickness is 25 ⁇ m. On the other hand, if the upper limit of the thickness of the polarizer protective film exceeds 300 ⁇ m, the thickness of the polarizing plate becomes too thick, which is not preferable.
- the upper limit of the thickness is preferably 200 ⁇ m.
- a particularly preferable upper limit of the thickness is 100 ⁇ m, which is about the same as a general TAC film.
- Polyethylene terephthalate is preferable as the polyester used as the film substrate in order to control the retardation within the range of the present invention even in the above thickness range.
- a method of blending the ultraviolet absorber into the polyester film a known method can be used in combination.
- a master batch is prepared by blending the dried ultraviolet absorber and the polymer raw material in advance using a kneading extruder. It can be prepared and blended by, for example, a method of mixing a predetermined master batch and a polymer raw material during film formation.
- the concentration of the UV absorber in the master batch is preferably 5 to 30% by mass in order to uniformly disperse the UV absorber and mix it economically.
- a condition for producing the master batch it is preferable to use a kneading extruder and to extrude at a temperature not lower than the melting point of the polyester raw material and not higher than 290 ° C. for 1 to 15 minutes. Above 290 ° C, the weight loss of the UV absorber is large, and the viscosity of the master batch is greatly reduced. When the extrusion temperature is 1 minute or less, uniform mixing of the UV absorber becomes difficult. At this time, if necessary, a stabilizer, a color tone adjusting agent, and an antistatic agent may be added.
- the polyester film has a multilayer structure of at least three layers and an ultraviolet absorber is added to the intermediate layer of the film.
- a film having a three-layer structure containing an ultraviolet absorber in the intermediate layer can be specifically produced as follows. Polyester pellets alone for the outer layer, master batches containing UV absorbers for the intermediate layer and polyester pellets are mixed at a predetermined ratio, dried, and then supplied to a known melt laminating extruder, which is slit-shaped. Extruded into a sheet form from a die and cooled and solidified on a casting roll to make an unstretched film.
- a three-layer manifold or a merging block for example, a merging block having a square merging portion
- a film layer constituting both outer layers and a film layer constituting an intermediate layer are laminated
- An unstretched film is formed by extruding a three-layer sheet from the die and cooling with a casting roll.
- the filter particle size (initial filtration efficiency 95%) of the filter medium used for high-precision filtration of the molten resin is preferably 15 ⁇ m or less. When the filter particle size of the filter medium exceeds 15 ⁇ m, removal of foreign matters of 20 ⁇ m or more tends to be insufficient.
- the biaxial refractive index (the refractive index in the slow axis direction: Ny, the fast axis (the refractive index in the direction perpendicular to the slow axis direction): Nx), and the refractive index in the thickness direction ( Nz) was determined by an Abbe refractometer (manufactured by Atago Co., Ltd., NAR-4T, measurement wavelength 589 nm).
- the biaxial refractive index anisotropy ( ⁇ Nxy) was determined by the following method. Using a molecular orientation meter (MOA-6004 type molecular orientation meter, manufactured by Oji Scientific Instruments Co., Ltd.), determine the slow axis direction of the film, 4 cm so that the slow axis direction is parallel to the long side of the measurement sample.
- MOA-6004 type molecular orientation meter manufactured by Oji Scientific Instruments Co., Ltd.
- a rectangle of ⁇ 2 cm was cut out and used as a measurement sample.
- Abbe refracts the biaxial refractive index (the refractive index in the slow axis direction: Ny, the refractive index in the direction perpendicular to the slow axis direction: Nx), and the refractive index (Nz) in the thickness direction.
- ) of the biaxial refractive index difference was determined as a refractive index anisotropy ( ⁇ Nxy), which was obtained by a refractive index meter (NAGO-4T manufactured by Atago Co., Ltd., measurement wavelength 589 nm).
- the thickness d (nm) of the film was measured using an electric micrometer (manufactured by Fine Reef, Millitron 1245D), and the unit was converted to nm.
- Retardation (Re) was determined from the product ( ⁇ Nxy ⁇ d) of refractive index anisotropy ( ⁇ Nxy) and film thickness d (nm).
- ) and ⁇ Nyz (
- NZ
- This light source had a plurality of peaks in the wavelength region of 600 nm or more and 780 nm or less, and the half-value width was evaluated at a peak near 630 nm having the highest peak intensity in this region. Moreover, the exposure time in the spectrum measurement was 20 msec.
- the reflection spectrum was measured using the Al mirror (part number 202-35988-05) attached as a standard to the specular reflection measuring device (part number 206-14064, manufactured by Shimadzu Corporation) as the standard mirror, with a total luminous flux of 5 °.
- the measurement was carried out by relative specular reflection at an incident angle of.
- the measurement was performed under the conditions of sampling pitch: 1 nm, sample mask opening size :: 5 mm ⁇ .
- the minimum value (minimum value) of the reflectance and the wavelength (bottom wavelength) at that time were determined from the obtained reflection spectrum.
- the obtained polyethylene terephthalate resin (A) had an intrinsic viscosity of 0.62 dl / g and contained substantially no inert particles and internally precipitated particles. (Hereafter, abbreviated as PET (A).)
- PET (B) 10 parts by weight of the dried UV absorber (2,2 ′-(1,4-phenylene) bis (4H-3,1-benzoxazinon-4-one), and PET (A) containing no particles (inherent 90 parts by mass of a viscosity of 0.62 dl / g) was mixed, and a polyethylene terephthalate resin (B) containing an ultraviolet absorber was obtained using a kneading extruder (hereinafter abbreviated as PET (B)).
- a transesterification reaction and a polycondensation reaction were carried out by a conventional method, and as a dicarboxylic acid component (based on the total dicarboxylic acid component) 46 mol% terephthalic acid, 46 mol% isophthalic acid and 8 mol% sodium 5-sulfonatoisophthalate, A water-dispersible sulfonic acid metal base-containing copolymer polyester resin having a composition of 50 mol% ethylene glycol and 50 mol% neopentyl glycol as a glycol component (based on the entire glycol component) was prepared.
- the internal temperature of the separable flask was raised to 80 ° C., and the entire amount of the monomer solution was added to the aqueous dispersion of the vinylidene fluoride / tetrafluoroethylene / chlorotrifluoroethylene copolymer particles over 3 hours. Further, simultaneously with the addition of the monomer solution, the polymerization proceeded while adding 41.1 g of 1% by mass of ammonium persulfate in 7 portions every 30 minutes. Five hours after the start of polymerization, the reaction solution was cooled to room temperature to complete the reaction, whereby an aqueous dispersion of acrylic-fluorine composite polymer particles was obtained. (Solid content concentration: 52.0% by mass) The mass ratio of the fluoropolymer portion to the acrylic polymer portion in the obtained acrylic-fluorine composite polymer particles was 50/50.
- the internal temperature of the separable flask was raised to 80 ° C., and the entire amount of the monomer solution was added to the aqueous dispersion of the vinylidene fluoride / tetrafluoroethylene / chlorotrifluoroethylene copolymer particles over 3 hours. Further, simultaneously with the addition of the monomer solution, the polymerization proceeded while adding 41.1 g of 1% by mass of ammonium persulfate in 7 portions every 30 minutes. Five hours after the start of the polymerization, the reaction solution was cooled to room temperature to complete the reaction, whereby an aqueous dispersion of acrylic-fluorine composite polymer particles was obtained (solid content concentration 52.0% by mass). The mass ratio of the fluoropolymer portion to the acrylic polymer portion in the obtained acrylic-fluorine composite polymer particles was 50/50.
- PET protective film 1 After drying 90 parts by mass of PET (A) resin pellets containing no particles as a raw material for the base film intermediate layer and 10 parts by mass of PET (B) resin pellets containing an ultraviolet absorber at 135 ° C. for 6 hours under reduced pressure (1 Torr) , And supplied to the extruder 2 (for the intermediate layer II layer). Also, the PET (A) was dried by an ordinary method and supplied to the extruder 1 (for the outer layer I layer and the outer layer III), and dissolved at 285 ° C. .
- the low-reflection layer is coated with the low-reflection layer coating liquid A of Production Example 4 on the side where the low-reflection layer of the unstretched PET film is formed by the reverse roll method so that the coating amount after drying is 0.108 g / m 2.
- the adhesive modification coating solution of Production Example 3 was applied on the side opposite to the layer-laminated surface so as to be 0.080 g / m 2, and then dried at 80 ° C. for 20 seconds.
- the unstretched film on which this coating layer was formed was guided to a tenter stretching machine, and the film was guided to a hot air zone at a temperature of 125 ° C. while being gripped by a clip, and stretched 4.0 times in the width direction.
- the film was treated at a temperature of 225 ° C. for 10 seconds, and further subjected to a relaxation treatment of 3.0% in the width direction to obtain a polarizer protective film 1 having a film thickness of about 100 ⁇ m. Obtained.
- the polarizer protective film 1 had retardation (Re) of 10300 nm, thickness direction retardation (Rth) of 12350 nm, Re / Rth of 0.834, and NZ coefficient of 1.699. Further, the reflection spectrum of the polarizer protective film 1 had a bottom wavelength of 630 nm and a reflectance at a wavelength of 630 nm of 1.71%.
- PET (Polarizer protective film 2) After drying 90 parts by mass of PET (A) resin pellets containing no particles as a raw material for the base film intermediate layer and 10 parts by mass of PET (B) resin pellets containing an ultraviolet absorber at 135 ° C. for 6 hours under reduced pressure (1 Torr) , And supplied to the extruder 2 (for the intermediate layer II layer). Also, the PET (A) was dried by an ordinary method and supplied to the extruder 1 (for the outer layer I layer and the outer layer III), and dissolved at 285 ° C. .
- the low-reflection layer is laminated on the side of the unstretched PET film on which the low-reflection layer is formed by the reverse roll method so that the coating amount after drying the coating liquid B of Production Example 5 is 0.09 g / m 2.
- the adhesive modification coating solution of Production Example 3 was applied to the opposite side of the coated surface to 0.08 g / m 2 and then dried at 80 ° C. for 20 seconds.
- the unstretched film on which this coating layer was formed was guided to a tenter stretching machine, and the film was guided to a hot air zone at a temperature of 125 ° C. while being gripped by a clip, and stretched 4.0 times in the width direction.
- the film was treated at a temperature of 225 ° C. for 10 seconds, and further subjected to a 3.0% relaxation treatment in the width direction to obtain a polarizer protective film 2 having a film thickness of about 100 ⁇ m. Obtained.
- the retardation (Re), retardation in the thickness direction (Rth), Re / Rth, and NZ coefficient of the polarizer protective film 2 were the same as those of the polarizer protective film 1.
- the reflection spectrum of the polarizer protective film 2 had a bottom wavelength of 550 nm and a reflectance at a wavelength of 550 nm of 1.96%.
- PET (Polarizer protective film 3) After drying 90 parts by mass of PET (A) resin pellets containing no particles as a raw material for the base film intermediate layer and 10 parts by mass of PET (B) resin pellets containing an ultraviolet absorber at 135 ° C. for 6 hours under reduced pressure (1 Torr) , And supplied to the extruder 2 (for the intermediate layer II layer). Also, the PET (A) was dried by an ordinary method and supplied to the extruder 1 (for the outer layer I layer and the outer layer III), and dissolved at 285 ° C. .
- the low-reflection layer is laminated on the side of the unstretched PET film on which the low-reflection layer is formed by the reverse roll method so that the coating amount after drying the coating liquid A of Production Example 4 is 0.106 g / m 2.
- the adhesive modification coating solution of Production Example 3 was applied to the opposite side of the coated surface to 0.080 g / m 2 and then dried at 80 ° C. for 20 seconds.
- the unstretched film on which this coating layer was formed was guided to a tenter stretching machine, and the film was guided to a hot air zone at a temperature of 125 ° C. while being gripped by a clip, and stretched 4.0 times in the width direction.
- the film was treated at a temperature of 225 ° C. for 10 seconds, and further subjected to a 3.0% relaxation treatment in the width direction to obtain a polarizer protective film 3 having a film thickness of about 100 ⁇ m. Obtained.
- the retardation (Re), thickness direction retardation (Rth), Re / Rth, and NZ coefficient of the polarizer protective film 3 were the same as those of the polarizer protective film 1.
- the reflection spectrum of the polarizer protective film 3 had a bottom wavelength of 615 nm and a reflectance at a wavelength of 615 nm of 1.71%.
- PET (Polarizer protective film 4) After drying 90 parts by mass of PET (A) resin pellets containing no particles as a raw material for the base film intermediate layer and 10 parts by mass of PET (B) resin pellets containing an ultraviolet absorber at 135 ° C. for 6 hours under reduced pressure (1 Torr) , And supplied to the extruder 2 (for the intermediate layer II layer). Also, the PET (A) was dried by an ordinary method and supplied to the extruder 1 (for the outer layer I layer and the outer layer III), and dissolved at 285 ° C. .
- the low-reflection layer is laminated on the side of the non-stretched PET film on which the low-reflection layer is formed by the reverse roll method so that the coating amount after drying the coating liquid A of Production Example 4 is 0.111 g / m 2.
- the adhesive modification coating solution of Production Example 3 was applied to the opposite side of the coated surface to 0.080 g / m 2 and then dried at 80 ° C. for 20 seconds.
- the unstretched film on which this coating layer was formed was guided to a tenter stretching machine, and the film was guided to a hot air zone at a temperature of 125 ° C. while being gripped by a clip, and stretched 4.0 times in the width direction.
- the film is treated at a temperature of 225 ° C. for 10 seconds, and further subjected to a 3.0% relaxation treatment in the width direction to obtain a polarizer protective film 4 having a film thickness of about 100 ⁇ m. Obtained.
- the retardation (Re), thickness direction retardation (Rth), Re / Rth, and NZ coefficient of the polarizer protective film 4 were the same as those of the polarizer protective film 1.
- the reflection spectrum of the polarizer protective film 4 had a bottom wavelength of 645 nm and a reflectance at a wavelength of 645 nm of 1.71%.
- PET (Polarizer protective film 5) After drying 90 parts by mass of PET (A) resin pellets containing no particles as a raw material for the base film intermediate layer and 10 parts by mass of PET (B) resin pellets containing an ultraviolet absorber at 135 ° C. for 6 hours under reduced pressure (1 Torr) , And supplied to the extruder 2 (for the intermediate layer II layer). Also, the PET (A) was dried by an ordinary method and supplied to the extruder 1 (for the outer layer I layer and the outer layer III), and dissolved at 285 ° C. .
- the low-reflective layer coating solution B of Production Example 5 is dried on the side where the low-reflective layer of this unstretched PET film is formed by the reverse roll method so that the coating amount after drying is 0.10 g / m 2.
- the adhesive modification coating solution of Production Example 3 was applied on the side opposite to the layer-laminated surface so as to be 0.08 g / m 2, and then dried at 80 ° C. for 20 seconds.
- the unstretched film on which this coating layer was formed was guided to a tenter stretching machine, and the film was guided to a hot air zone at a temperature of 125 ° C. while being gripped by a clip, and stretched 4.0 times in the width direction.
- the film was treated at a temperature of 225 ° C. for 10 seconds, and further subjected to a relaxation treatment of 3.0% in the width direction to obtain a polarizer protective film 5 having a film thickness of about 100 ⁇ m. Obtained.
- the polarizer protective film 5 had retardation (Re) of 10300 nm, thickness direction retardation (Rth) of 12350 nm, Re / Rth of 0.834, and NZ coefficient of 1.699. Further, the reflection spectrum of the polarizer protective film 5 had a bottom wavelength of 630 nm and a reflectance at a wavelength of 630 nm of 1.96%.
- PET (Polarizer protective film 6) After drying 90 parts by mass of PET (A) resin pellets containing no particles as a raw material for the base film intermediate layer and 10 parts by mass of PET (B) resin pellets containing an ultraviolet absorber at 135 ° C. for 6 hours under reduced pressure (1 Torr) , And supplied to the extruder 2 (for the intermediate layer II layer). Also, the PET (A) was dried by an ordinary method and supplied to the extruder 1 (for the outer layer I layer and the outer layer III), and dissolved at 285 ° C. .
- the coating material for modified adhesive of Production Example 3 was coated on the low reflective side so that the coating amount after drying was 0.10 g / m 2 on the low reflective side. After coating so that the opposite surface was 0.08 g / m 2 , it was dried at 80 ° C. for 20 seconds.
- the unstretched film on which this coating layer was formed was guided to a tenter stretching machine, and the film was guided to a hot air zone at a temperature of 125 ° C. while being gripped by a clip, and stretched 4.0 times in the width direction.
- the film was treated at a temperature of 225 ° C. for 10 seconds, and further subjected to a relaxation treatment of 3.0% in the width direction to obtain a polarizer protective film 6 having a film thickness of about 100 ⁇ m. Obtained.
- the retardation (Re), thickness direction retardation (Rth), Re / Rth, and NZ coefficient of the polarizer protective film 6 were the same as those of the polarizer protective film 1.
- the reflection spectrum of the polarizer protective film 6 had a bottom wavelength of 600 nm, and the reflectance at a wavelength of 600 nm was 3.7%.
- Example 1 A polarizer protective film 1 is attached to one side of a polarizer composed of PVA and iodine so that the transmission axis of the polarizer and the fast axis of the film are perpendicular to each other, and a TAC film (Fuji Film Co., Ltd.) Manufactured and having a thickness of 80 ⁇ m) to make a polarizing plate.
- the polarizer was laminated
- the polarizing plate on the viewing side of REGZA 43J10X manufactured by Toshiba Corporation was replaced with the polarizing plate prepared above so that the polyester film was on the side opposite to the liquid crystal (distal), thereby producing a liquid crystal display device.
- the direction of the transmission axis of a polarizing plate might be the same as the direction of the transmission axis of the polarizing plate before replacement.
- Example 1 A liquid crystal display device was produced in the same manner as in Example 1 except that the polarizer protective film 2 was used instead of the polarizer protective film 1.
- Example 2 A liquid crystal display device was produced in the same manner as in Example 1 except that the polarizer protective film 3 was used instead of the polarizer protective film 1.
- Example 3 A liquid crystal display device was produced in the same manner as in Example 1 except that the polarizer protective film 4 was used instead of the polarizer protective film 1.
- Example 4 A liquid crystal display device was produced in the same manner as in Example 1, except that the polarizer protective film 5 was used instead of the polarizer protective film 1.
- Example 2 A liquid crystal display device was produced in the same manner as in Example 1 except that the polarizer protective film 6 was used instead of the polarizer protective film 1.
- the polyester film had a thickness of 100 ⁇ m, but this was a 80 ⁇ m film (retardation (Re) was 8080 nm, retardation in the thickness direction (Rth) was 9960 nm, Re / Rth was 0.811, and the NZ coefficient was 1.733), and liquid crystal display devices of Examples 1 ′ to 4 ′ and Comparative Examples 1 ′ to 2 ′ were prepared. The same permutation tendency as in Comparative Examples 1 and 2 was confirmed.
- the polyester film had a thickness of 100 ⁇ m, but this was a 60 ⁇ m film (retardation (Re) was 6060 nm, and thickness direction retardation (Rth) was 7470 nm. Re / Rth was 0.811 and NZ coefficient was 1.733), and liquid crystal display devices of Examples 1 ′′ to 4 ′′ and Comparative Examples 1 ′′ to 2 ′′ were manufactured. The same permutation tendency as in Examples 1 to 4 and Comparative Examples 1 and 2 was confirmed.
- the liquid crystal display device and polarizing plate of the present invention can ensure good visibility in which the occurrence of rainbow-like color spots is significantly suppressed at any angle, and the contribution to the industry is great.
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Abstract
Description
線形状に着目すると、配向ポリエステルフィルムのレタデーションを制御することで、光源の発光スペクトルと相似なスペクトルを得ることが可能となり、これにより虹斑を抑制することが可能となった。
項1.
バックライト光源、2つの偏光板、及び前記2つの偏光板の間に配置された液晶セルを有する液晶表示装置であって、
前記バックライト光源は、400nm以上495nm未満、495nm以上600nm未満及び600nm以上780nm以下の各波長領域にそれぞれ発光スペクトルのピークトップを有し、かつ、600nm以上780nm以下の波長領域における最もピーク強度の高いピークの半値幅が5nm未満である発光スペクトルを有する白色発光ダイオードであり、
前記偏光板のうち少なくとも一方の偏光板は、偏光子の少なくとも一方の面にポリエステルフィルムが積層されたものであり、
前記ポリエステルフィルムは、1500nm以上30000nm以下のリタデーションを有し、
前記ポリエステルフィルムの一方の面に反射防止層及び/又は低反射層が積層されており、
前記反射防止層及び/又は低反射層が積層されたポリエステルフィルムは、反射防止層及び/又は低反射層が積層された側から測定した反射スペクトルが、600nm以上780nm以下の波長領域にボトム波長を有し、ボトム波長での反射率が2%以下であることを特徴とする液晶表示装置。
項2.
前記バックライト光源の発光スペクトルは、
400nm以上495nm未満の波長領域における最もピーク強度の高いピークの半値幅が5nm以上であり、
495nm以上600nm未満の波長領域における最もピーク強度の高いピークの半値幅が5nm以上である、
項1に記載の液晶表示装置。
項3.
ポリエステルフィルムの一方の面に反射防止層及び/又は低反射層が積層された偏光子保護フィルムであって、
前記ポリエステルフィルムは、1500nm以上30000nm以下のリタデーションを有し、
前記反射防止層及び/又は低反射層が積層されたポリエステルフィルムは、反射防止層及び/又は低反射層が積層された側から測定した反射スペクトルが、600nm以上780nm以下の波長領域にボトム波長を有し、ボトム波長での反射率が2%以下である、偏光子保護フィルム。
項4.
偏光子の少なくとも一方の面に項3に記載の偏光子保護フィルムが積層された偏光板。
複数のピークが、それぞれ独立したピークである場合、最もピーク強度の高いピークの半値幅が上記範囲であることが好ましい。さらに、最も高いピーク強度の70%以上の強度を有する他のピークについても、同様に半値幅が上記範囲になることがより好ましい態様である。
複数のピークが重なった形状を有する一個の独立したピークについては、複数のピークのうち最もピーク強度の高いピークの半値幅をそのまま測定できる場合には、その半値幅を用いる。ここで、独立したピークとは、ピークの短波長側、長波長側の両方にピーク強度の1/2になる強度の領域を有するものである。すなわち、複数のピークが重なり、個々のピークがその両側にピーク強度の1/2になる強度の領域を有さない場合は、その複数のピークを全体として一個のピークと見なす。この様な、複数のピークが重なった形状を有する一個のピークは、その中の最も高いピーク強度の、1/2の強度におけるピークの幅(nm)を半値幅とする。
なお、複数のピークのうち、最もピーク強度の高い点をピークトップとする。
なお、400nm以上495nm未満の波長領域、495nm以上600nm未満の波長領域、又は600nm以上780nm以下の波長領域のそれぞれの波長領域における最も高いピーク強度を持つピークは他の波長領域のピークとはお互い独立した関係にあることが好ましい。特に、495nm以上600nm未満の波長領域で最も高いピーク強度を持つピークと、600nm以上780nm以下の領域で最も高いピーク強度を持つピークとの間の波長領域には、強度が600nm以上780nm以下の波長領域の最も高いピーク強度を持つピークのピーク強度の1/3以下になる領域が存在することが色彩の鮮明性の面で好ましい。
偏光子を通過し、配向ポリエステルフィルムに入射する光は直線偏光であり、直線偏光の状態では波長に対する透過率依存性は無いと考えられる。直線偏光の入射光は配向ポリエステルフィルムを通過することで楕円偏光や円偏光に変化する。位相差δは、δ=2π×Re/λ(Re:レタデーション,λ:波長)で表され、波長λにより位相差δが異なる。つまり光の波長λによって、直線偏光、楕円偏光、円偏光の変化サイクルが異なるため、配向ポリエステルフィルムを出射する際の偏光状態が波長によって異なると考えられる。配向ポリエステルフィルムから視認側に出射される際は、入射面に対して平行なP偏光成分よりも垂直なS偏光成分が反射されやすく、法線からの視認角度が大きくなるにつれてこの差(P偏光成分とS偏光成分の差)は大きくなる傾向がある。偏光度が異なる各波長の光は、反射されやすいS偏光の影響がそれぞれ異なるため、界面を通過する際に各透過率が変化する。界面を通過する際にS偏光成分が多い波長帯の透過率が低下することとなり、これが虹状の色斑が発生する要因の一つとなっていると考えられる。特に600nm以上780nm以下の赤色領域で急峻なピークを持つ場合、波長による透過率変化が大きいため、色斑が出やすくなる。薄膜干渉を利用すると任意の波長の界面反射を抑えることができるため、赤色領域(600nm以上780nm以下)にボトム波長を有する反射防止層及び/又は低反射層を形成することで赤色領域の透過率を向上すなわちS偏光成分の反射を抑えることで可能になると考えられる。急峻な赤色領域において、S偏光成分の透過率が向上するため、偏光子を通過した入射光に対して配向ポリエステルフィルムの出射光の透過率変化が少なくなることで、虹状の色斑を抑えることができる。
出射光側に配置される偏光板については、上記ポリエステルフィルムからなる偏光子保護フィルムは、その偏光子を起点として液晶側に配置されても、出射光側に配置されていても、両側に配置されていてもよいが、少なくとも出射光側に配置されていることが好ましい。
入射光側に配される偏光板においても、上記ポリエステルフィルムからなる偏光子保護フィルムは、その偏光子を起点として入射光側に配置していても、液晶セル側に配置していても、両側に配置されていても良いが、少なくとも入射光側に配置されていることが好ましい態様である。また、入射光側に配される偏光板は、ポリエステルフィルムからなる偏光子保護フィルムは使用せず、トリアセチルセルロースフィルム等の複屈折が実質的にない(リタデーションの低い)偏光子保護フィルムを使用したものであってもよい。
反射防止層及び/又は低反射層を積層したポリエステルフィルムの反射スペクトルは、600nm以上780nm以下の波長領域にボトム波長を有し、ボトム波長での反射率が2%以下であることを特徴とする。この反射スペクトルは、反射防止層及び/又は低反射層が積層された側から測定されるものである。反射スペクトルのボトム波長とは、400nm~780nmの反射スペクトルにおいて反射率が最小となる波長である。本発明で用いられる反射防止層及び/又は低反射層のボトム波長における反射率は2%以下が好ましい。2%を超えると、虹状の色斑が視認されやすくなることから好ましくない。反射率は、より好ましくは2%未満であり、より好ましくは1.6%以下であり、更に好ましくは1.2%以下、特に好ましくは1%以下である。反射率の下限は特に限定されないが、例えば、0.01%である。反射率0%が最も好ましい。
なお、反射防止層を積層する場合、前記反射率の上限は1%未満が好ましい。低反射層を積層する場合、前記反射率の上限は2%以下が好ましく、より好ましくは2%未満であり、下限は1%程度が好ましい。
反射率の測定は、後述する実施例に記載の方法で行うことができる。
(第5層)
(第5層~第4層)
5層全体での反射率は以下の式で得られる。
分子配向計(王子計測器株式会社製、MOA-6004型分子配向計)を用いて、フィルムの遅相軸方向を求め、遅相軸方向が測定用サンプル長辺と平行になるように、4cm×2cmの長方形を切り出し、測定用サンプルとした。このサンプルについて、直交する二軸の屈折率(遅相軸方向の屈折率:Ny,進相軸(遅相軸方向と直交する方向の屈折率):Nx)、及び厚さ方向の屈折率(Nz)をアッベ屈折率計(アタゴ社製、NAR-4T、測定波長589nm)によって求めた。
リタデーションとは、フィルム上の直交する二軸の屈折率の異方性(△Nxy=|Nx-Ny|)とフィルム厚みd(nm)との積(△Nxy×d)で定義されるパラメーターであり、光学的等方性、異方性を示す尺度である。二軸の屈折率の異方性(△Nxy)は、以下の方法により求めた。分子配向計(王子計測器株式会社製、MOA-6004型分子配向計)を用いて、フィルムの遅相軸方向を求め、遅相軸方向が測定用サンプル長辺と平行になるように、4cm×2cmの長方形を切り出し、測定用サンプルとした。このサンプルについて、直交する二軸の屈折率(遅相軸方向の屈折率:Ny,遅相軸方向と直交する方向の屈折率:Nx)、及び厚さ方向の屈折率(Nz)をアッベ屈折率計(アタゴ社製、NAR-4T、測定波長589nm)によって求め、前記二軸の屈折率差の絶対値(|Nx-Ny|)を屈折率の異方性(△Nxy)とした。フィルムの厚みd(nm)は電気マイクロメータ(ファインリューフ社製、ミリトロン1245D)を用いて測定し、単位をnmに換算した。屈折率の異方性(△Nxy)とフィルムの厚みd(nm)の積(△Nxy×d)より、リタデーション(Re)を求めた。
厚さ方向リタデーションとは、フィルム厚さ方向断面から見たときの2つの複屈折△Nxz(=|Nx-Nz|)、△Nyz(=|Ny-Nz|)にそれぞれフィルム厚さdを掛けて得られるリタデーションの平均を示すパラメーターである。リタデーションの測定と同様の方法でNx、Ny、Nzとフィルム厚みd(nm)を求め、(△Nxz×d)と(△Nyz×d)との平均値を算出して厚さ方向リタデーション(Rth)を求めた。
上記(1)により得られた、Ny、Nx、Nzの値を式:NZ=|Ny-Nz|/|Ny-Nx|に代入してNZ係数を求めた。
各実施例で使用する液晶表示装置には、東芝社製のREGZA 43J10Xを用いた。この液晶表示装置のバックライト光源(白色発光ダイオード)の発光スペクトルを、浜松ホトニクス製 マルチチャンネル分光器 PMA-12を用いて測定したところ、450nm、535nm、630nm付近にピークトップを有する発光スペクトルが観察された。各ピークトップの半値幅(各波長領域における最も高いピーク強度を有するピークの半値幅)は、それぞれ450nmのピークが17nm、535nmのピークが45nm、630nmのピークが2nmであった。なお、この光源では600nm以上780nm以下の波長領域に複数のピークを有したが、この領域で最もピーク強度の高い630nm付近のピークで半値幅を評価した。また、スペクトル測定の際の露光時間は20msecとした。
得られた偏光子保護フィルムから任意の位置でA4サイズに切り出し、低反射層(又は反射防止層)が積層された面とは反対の基材面に耐水サンドペーパーで均一にキズをつけた後、黒マジックインキ(登録商標)を塗り、さらに黒テープ(日東電工製ビニルテープNo.21黒)を貼ることで低反射層(又は反射防止層)の反対面の反射を無くしたサンプルを作製した。作製したサンプルは島津製作所(株)製の分光光度計UV-3150を用いて低反射層(又は反射防止層)の400~800nmにおける反射スペクトルを測定した。反射スペクトル測定条件は、鏡面反射測定装置(島津製作所(株)製 部品番号206-14064)に標準で添付されたAl蒸着ミラー(部品番号202-35988-05)を基準ミラーとし、全光束5°の入射角で相対鏡面反射で実施した。その他、サンプリングピッチ:1nm、試料マスクの開口寸法::5mmφの条件で測定した。得られた反射スペクトルから反射率の最小値(極小値)及びその際の波長(ボトム波長)を求めた。
エステル化反応缶を昇温し200℃に到達した時点で、テレフタル酸を86.4質量部およびエチレングリコール64.6質量部を仕込み、撹拌しながら触媒として三酸化アンチモンを0.017質量部、酢酸マグネシウム4水和物を0.064質量部、及びトリエチルアミン0.16質量部を仕込んだ。ついで、加圧昇温を行いゲージ圧0.34MPa、240℃の条件で加圧エステル化反応を行った後、エステル化反応缶を常圧に戻し、リン酸0.014質量部を添加した。さらに、15分かけて260℃に昇温し、リン酸トリメチル0.012質量部を添加した。次いで15分後に、高圧分散機で分散処理を行い、15分後、得られたエステル化反応生成物を重縮合反応缶に移送し、280℃で減圧下重縮合反応を行った。
乾燥させた紫外線吸収剤(2,2’-(1,4-フェニレン)ビス(4H-3,1-ベンズオキサジノン-4-オン)10質量部、及び粒子を含有しないPET(A)(固有粘度が0.62dl/g)90質量部を混合し、混練押出機を用い、紫外線吸収剤含有するポリエチレンテレフタレート樹脂(B)を得た。(以後、PET(B)と略す。)
常法によりエステル交換反応および重縮合反応を行って、ジカルボン酸成分として(ジカルボン酸成分全体に対して)テレフタル酸46モル%、イソフタル酸46モル%および5-スルホナトイソフタル酸ナトリウム8モル%、グリコール成分として(グリコール成分全体に対して)エチレングリコール50モル%およびネオペンチルグリコール50モル%の組成の水分散性スルホン酸金属塩基含有共重合ポリエステル樹脂を調製した。次いで、水51.4質量部、イソプロピルアルコール38質量部、n-ブチルセルソルブ5質量部、及びノニオン系界面活性剤0.06質量部を混合した後、加熱撹拌し、77℃に達したら、上記水分散性スルホン酸金属塩基含有共重合ポリエステル樹脂5質量部を加え、樹脂の固まりが無くなるまで撹拌し続けた後、樹脂水分散液を常温まで冷却して、固形分濃度5.0質量%の均一な水分散性共重合ポリエステル樹脂液を得た。さらに、凝集体シリカ粒子(富士シリシア(株)社製、サイリシア310)3質量部を水50質量部に分散させた後、上記水分散性共重合ポリエステル樹脂液99.46質量部にサイリシア310の水分散液0.54質量部を加えて、撹拌しながら水20質量部を加えて、接着性改質塗布液を得た。
ビニリデンフルオライド系重合体粒子として、ビニリデンフルオライド/テトラフルオロエチレン/クロロトリフルオロエチレン共重合体(=72.1/14.9/13(モル%))の粒子の水性分散液(固形分濃度45.5質量%)571.4gを2Lガラス製セパラブルフラスコに入れ、乳化剤としてニューコール707SF(日本乳化剤(株)製)37.1gと、水59.3gを加えて十分に混合して水性分散液を調整した。
ビニリデンフルオライド系重合体粒子として、ビニリデンフルオライド/テトラフルオロエチレン/クロロトリフルオロエチレン共重合体(=72.1/14.9/13(モル%))の粒子の水性分散液(固形分濃度45.5質量%)571.4gを2Lガラス製セパラブルフラスコに入れ、乳化剤としてニューコール707SF(日本乳化剤(株)製)37.1gと、水59.3gを加えて十分に混合して水性分散液を調整した。
基材フィルム中間層用原料として粒子を含有しないPET(A)樹脂ペレット90質量部と紫外線吸収剤を含有したPET(B)樹脂ペレット10質量部を135℃で6時間減圧乾燥(1Torr)した後、押出機2(中間層II層用)に供給し、また、PET(A)を常法により乾燥して押出機1(外層I層および外層III用)にそれぞれ供給し、285℃で溶解した。この2種のポリマーを、それぞれステンレス焼結体の濾材(公称濾過精度10μm粒子95%カット)で濾過し、2種3層合流ブロックにて、積層し、口金よりシート状にして押し出した後、静電印加キャスト法を用いて表面温度30℃のキャスティングドラムに巻きつけて冷却固化し、未延伸フィルムを作った。この時、I層、II層、III層の厚さの比は10:80:10となるように各押し出し機の吐出量を調整した。
偏光子保護フィルム1は、リタデーション(Re)が10300nm、厚さ方向のリタデーション(Rth)が12350nm、Re/Rthが0.834、NZ係数が1.699であった。
また、偏光子保護フィルム1の反射スペクトルは、ボトム波長が630nmであり、波長630nmにおける反射率は1.71%であった。
基材フィルム中間層用原料として粒子を含有しないPET(A)樹脂ペレット90質量部と紫外線吸収剤を含有したPET(B)樹脂ペレット10質量部を135℃で6時間減圧乾燥(1Torr)した後、押出機2(中間層II層用)に供給し、また、PET(A)を常法により乾燥して押出機1(外層I層および外層III用)にそれぞれ供給し、285℃で溶解した。この2種のポリマーを、それぞれステンレス焼結体の濾材(公称濾過精度10μm粒子95%カット)で濾過し、2種3層合流ブロックにて、積層し、口金よりシート状にして押し出した後、静電印加キャスト法を用いて表面温度30℃のキャスティングドラムに巻きつけて冷却固化し、未延伸フィルムを作った。この時、I層、II層、III層の厚さの比は10:80:10となるように各押し出し機の吐出量を調整した。
偏光子保護フィルム2のリタデーション(Re)、厚さ方向のリタデーション(Rth)、Re/Rth、NZ係数は、偏光子保護フィルム1と同じであった。 偏光子保護フィルム2の反射スペクトルは、ボトム波長が550nmであり、波長550nmにおける反射率は1.96%であった。
基材フィルム中間層用原料として粒子を含有しないPET(A)樹脂ペレット90質量部と紫外線吸収剤を含有したPET(B)樹脂ペレット10質量部を135℃で6時間減圧乾燥(1Torr)した後、押出機2(中間層II層用)に供給し、また、PET(A)を常法により乾燥して押出機1(外層I層および外層III用)にそれぞれ供給し、285℃で溶解した。この2種のポリマーを、それぞれステンレス焼結体の濾材(公称濾過精度10μm粒子95%カット)で濾過し、2種3層合流ブロックにて、積層し、口金よりシート状にして押し出した後、静電印加キャスト法を用いて表面温度30℃のキャスティングドラムに巻きつけて冷却固化し、未延伸フィルムを作った。この時、I層、II層、III層の厚さの比は10:80:10となるように各押し出し機の吐出量を調整した。
偏光子保護フィルム3のリタデーション(Re)、厚さ方向のリタデーション(Rth)、Re/Rth、NZ係数は、偏光子保護フィルム1と同じであった。 偏光子保護フィルム3の反射スペクトルは、ボトム波長が615nmであり、波長615nmにおける反射率は1.71%であった。
基材フィルム中間層用原料として粒子を含有しないPET(A)樹脂ペレット90質量部と紫外線吸収剤を含有したPET(B)樹脂ペレット10質量部を135℃で6時間減圧乾燥(1Torr)した後、押出機2(中間層II層用)に供給し、また、PET(A)を常法により乾燥して押出機1(外層I層および外層III用)にそれぞれ供給し、285℃で溶解した。この2種のポリマーを、それぞれステンレス焼結体の濾材(公称濾過精度10μm粒子95%カット)で濾過し、2種3層合流ブロックにて、積層し、口金よりシート状にして押し出した後、静電印加キャスト法を用いて表面温度30℃のキャスティングドラムに巻きつけて冷却固化し、未延伸フィルムを作った。この時、I層、II層、III層の厚さの比は10:80:10となるように各押し出し機の吐出量を調整した
。
偏光子保護フィルム4のリタデーション(Re)、厚さ方向のリタデーション(Rth)、Re/Rth、NZ係数は、偏光子保護フィルム1と同じであった。
偏光子保護フィルム4の反射スペクトルは、ボトム波長が645nmであり、波長645nmにおける反射率は1.71%であった。
基材フィルム中間層用原料として粒子を含有しないPET(A)樹脂ペレット90質量部と紫外線吸収剤を含有したPET(B)樹脂ペレット10質量部を135℃で6時間減圧乾燥(1Torr)した後、押出機2(中間層II層用)に供給し、また、PET(A)を常法により乾燥して押出機1(外層I層および外層III用)にそれぞれ供給し、285℃で溶解した。この2種のポリマーを、それぞれステンレス焼結体の濾材(公称濾過精度10μm粒子95%カット)で濾過し、2種3層合流ブロックにて、積層し、口金よりシート状にして押し出した後、静電印加キャスト法を用いて表面温度30℃のキャスティングドラムに巻きつけて冷却固化し、未延伸フィルムを作った。この時、I層、II層、III層の厚さの比は10:80:10となるように各押し出し機の吐出量を調整した
。
偏光子保護フィルム5は、リタデーション(Re)が10300nm、厚さ方向のリタデーション(Rth)が12350nm、Re/Rthが0.834、NZ係数が1.699であった。
また、偏光子保護フィルム5の反射スペクトルは、ボトム波長が630nmであり、波長630nmにおける反射率は1.96%であった。
基材フィルム中間層用原料として粒子を含有しないPET(A)樹脂ペレット90質量部と紫外線吸収剤を含有したPET(B)樹脂ペレット10質量部を135℃で6時間減圧乾燥(1Torr)した後、押出機2(中間層II層用)に供給し、また、PET(A)を常法により乾燥して押出機1(外層I層および外層III用)にそれぞれ供給し、285℃で溶解した。この2種のポリマーを、それぞれステンレス焼結体の濾材(公称濾過
精度10μm粒子95%カット)で濾過し、2種3層合流ブロックにて、積層し、口金よりシート状にして押し出した後、静電印加キャスト法を用いて表面温度30℃のキャスティングドラムに巻きつけて冷却固化し、未延伸フィルムを作った。この時、I層、II層、III層の厚さの比は10:80:10となるように各押し出し機の吐出量を調整した
。
偏光子保護フィルム6のリタデーション(Re)、厚さ方向のリタデーション(Rth)、Re/Rth、NZ係数は、偏光子保護フィルム1と同じであった。
偏光子保護フィルム6の反射スペクトルは、ボトム波長が600nmであり、波長600nmにおける反射率は3.7%であった。
PVAとヨウ素からなる偏光子の片側に偏光子保護フィルム1を偏光子の透過軸とフィルムの進相軸が垂直になるように貼り付け、その反対の面にTACフィルム(富士フイルム(株)社製、厚み80μm)を貼り付けて偏光板を作成した。なお、偏光子保護フィルムの低反射層が積層されていない面に、偏光子を積層して偏光板を作成した。東芝社製のREGZA 43J10Xの視認側の偏光板を、ポリエステルフィルムが液晶とは反対側(遠位)となるように上記で作成した偏光板に置き換えて、液晶表示装置を作成した。なお、偏光板の透過軸の方向が、置き換え前の偏光板の透過軸の方向と同一となるよう置き換えた。
実施例1において、偏光子保護フィルム1の代わりに、偏光子保護フィルム2を用いた以外は同様にして、液晶表示装置を作成した。
実施例1において、偏光子保護フィルム1の代わりに、偏光子保護フィルム3を用いた以外は同様にして、液晶表示装置を作成した。
実施例1において、偏光子保護フィルム1の代わりに、偏光子保護フィルム4を用いた以外は同様にして、液晶表示装置を作成した。
実施例1において、偏光子保護フィルム1の代わりに、偏光子保護フィルム5を用いた以外は同様にして、液晶表示装置を作成した。
実施例1において、偏光子保護フィルム1の代わりに、偏光子保護フィルム6を用いた以外は同様にして、液晶表示装置を作成した。
Claims (4)
- バックライト光源、2つの偏光板、及び前記2つの偏光板の間に配置された液晶セルを有する液晶表示装置であって、
前記バックライト光源は、400nm以上495nm未満、495nm以上600nm未満及び600nm以上780nm以下の各波長領域にそれぞれ発光スペクトルのピークトップを有し、かつ、600nm以上780nm以下の波長領域における最もピーク強度の高いピークの半値幅が5nm未満である発光スペクトルを有する白色発光ダイオードであり、
前記偏光板のうち少なくとも一方の偏光板は、偏光子の少なくとも一方の面にポリエステルフィルムが積層されたものであり、
前記ポリエステルフィルムは、1500nm以上30000nm以下のリタデーションを有し、
前記ポリエステルフィルムの一方の面に反射防止層及び/又は低反射層が積層されており、
前記反射防止層及び/又は低反射層が積層されたポリエステルフィルムは、反射防止層及び/又は低反射層が積層された側から測定した反射スペクトルが、600nm以上780nm以下の波長領域にボトム波長を有し、ボトム波長での反射率が2%以下であることを特徴とする液晶表示装置。 - 前記バックライト光源の発光スペクトルは、
400nm以上495nm未満の波長領域における最もピーク強度の高いピークの半値幅が5nm以上であり、
495nm以上600nm未満の波長領域における最もピーク強度の高いピークの半値幅が5nm以上である、
請求項1に記載の液晶表示装置。 - ポリエステルフィルムの一方の面に反射防止層及び/又は低反射層が積層された偏光子保護フィルムであって、
前記ポリエステルフィルムは、1500nm以上30000nm以下のリタデーションを有し、
前記反射防止層及び/又は低反射層が積層されたポリエステルフィルムは、反射防止層及び/又は低反射層が積層された側から測定した反射スペクトルが、600nm以上780nm以下の波長領域にボトム波長を有し、ボトム波長での反射率が2%以下である、偏光子保護フィルム。 - 偏光子の少なくとも一方の面に請求項3に記載の偏光子保護フィルムが積層された偏光板。
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CN112805603B (zh) * | 2018-10-02 | 2023-10-20 | 东洋纺株式会社 | 液晶显示装置、偏光板和偏振片保护薄膜 |
TWI821425B (zh) * | 2018-10-02 | 2023-11-11 | 日商東洋紡股份有限公司 | 液晶顯示裝置、偏光板及偏光鏡保護膜 |
JP7476794B2 (ja) | 2018-10-02 | 2024-05-01 | 東洋紡株式会社 | 液晶表示装置、偏光板および偏光子保護フィルム |
KR102682719B1 (ko) * | 2018-10-02 | 2024-07-12 | 도요보 가부시키가이샤 | 액정 표시 장치, 편광판 및 편광자 보호 필름 |
JP2023081987A (ja) * | 2019-02-19 | 2023-06-13 | 東洋紡株式会社 | 偏光板の製造方法 |
WO2023243508A1 (ja) * | 2022-06-14 | 2023-12-21 | 東洋紡株式会社 | 紫外線吸収性ポリエステルフィルムおよび偏光子保護フィルム、偏光板並びに画像表示装置 |
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KR102307182B1 (ko) | 2021-09-30 |
TWI760447B (zh) | 2022-04-11 |
CN110300918A (zh) | 2019-10-01 |
JPWO2018159569A1 (ja) | 2019-12-19 |
CN110300918B (zh) | 2022-05-10 |
TW201841769A (zh) | 2018-12-01 |
JP7070539B2 (ja) | 2022-05-18 |
KR20190116334A (ko) | 2019-10-14 |
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