JP2016200816A - Liquid crystal display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display using a white light source that has an emission spectrum having peak tops in R, G, and B wavelength regions, where the half band widths of the peaks are relatively narrow, the liquid crystal display suppressing the generation of mottled rainbow even when a polyester film is used as a polarizer protective film that is a constitution member of a polarizing plate.SOLUTION: There is provided a liquid crystal display comprising a backlight source, two polarizing plates, and a liquid crystal cell arranged between the two polarizing plates, wherein the backlight source has peak tops of an emission spectrum in wavelength regions of 400 nm or more and less than 495 nm, 495 nm or more and less than 600 nm, and 600 nm or more and 750 nm or less, where half band widths of the peaks are 5 nm or more; at least one of the two polarizing plates is obtained by laminating a polyester film on at least one face of a polarizer via an adhesive layer; a difference between the refractive index of the adhesion layer and the refractive index of the polyester film in a direction parallel to a transmission axis of the polarizer is 0.13 or less.SELECTED DRAWING: None

Description

  The present invention relates to 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 (LCD) is usually configured by sandwiching a polarizer obtained by dyeing iodine in polyvinyl alcohol (PVA) or the like between two polarizer protective films. In general, a triacetyl cellulose (TAC) film is used. In recent years, with the thinning of LCDs, there has been a demand for thinner polarizing plates. However, if the thickness of the TAC film used as the protective film is reduced for this purpose, sufficient mechanical strength cannot be obtained and moisture permeability deteriorates. Moreover, although a TAC film is very expensive and a polyester film has been proposed as an inexpensive alternative material (Patent Documents 1 to 3), there is a problem that rainbow-like color spots are observed.

  When an oriented polyester film having birefringence is disposed on one side of the polarizer, 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).

  As means for solving the above problems, it is possible to use 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. It has been proposed (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 that has passed 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.

  In addition, by making the orientation direction of the oriented polyester film and the polarization direction of the polarizing plate orthogonal or parallel, the linearly polarized light emitted from the polarizer passes through the oriented polyester film while maintaining the polarization state. become. Further, by increasing the uniaxial orientation by controlling the birefringence of the oriented polyester film, light incident from an oblique direction also passes through while maintaining the polarization state. When the oriented polyester film is viewed from an oblique direction, a displacement occurs in the orientation main axis direction as compared to when viewed from directly above. However, when the uniaxial orientation is high, the displacement in the orientation principal axis direction when viewed from the oblique direction is reduced. For this reason, it is considered that the deviation between the direction of linearly polarized light and the direction of the main axis of orientation becomes small, and the change in polarization state is less likely to occur. In this way, by controlling the emission spectrum of the light source, the orientation state of the birefringent body, and the orientation main axis direction, the change in the polarization state is suppressed, and the visibility is significantly improved without causing rainbow-like color spots. It was thought to be.

JP 2002-116320 A JP 2004-219620 A JP 2004-205773 A WO2011 / 162198

  White light-emitting diodes (white LEDs) consisting of light-emitting elements that combine blue light-emitting diodes and yttrium / aluminum / garnet-based yellow phosphors (YAG-based yellow phosphors) have been widely used as backlight sources for liquid crystal display devices. It has been. The emission spectrum of this white light source is widely used as a backlight light source because it has a broad spectrum in the visible light region and is excellent in luminous efficiency. However, in a liquid crystal display device using this white LED as a backlight light source, the color can be reproduced only about 20% of the spectrum recognizable by human eyes.

  On the other hand, due to the increasing demand for color gamut in recent years, there is a liquid crystal display device in which the emission spectrum of a white light source has a clear peak shape in each wavelength region of R (red), G (green), and B (blue). Has been developed. For example, a white light source using quantum dot technology, a phosphor type white LED light source using a phosphor and a blue LED having a clear emission peak in the R (red) and G (green) regions by excitation light, three wavelengths Liquid crystal display devices that support a wide color gamut using various types of light sources such as a white LED light source of a type and a white LED light source combined with a red laser have been developed. In the case of a liquid crystal display device using a white light source using quantum dot technology as a backlight light source, it is said that it is possible to reproduce colors of 60% or more of the spectrum that can be recognized by human eyes. Each of these white light sources has a relatively narrow peak half-value width as compared with a light source composed of a white light emitting diode using a conventional YAG yellow phosphor, and an oriented polyester film having retardation is used as a constituent member of a polarizing plate. It was newly found that when used as a polarizer protective film, rainbow spots may occur depending on the type of light source.

  In the present invention, in a liquid crystal display device using a white light source having a peak top in each wavelength region of R, G, and B, and having a relatively narrow emission spectrum, the polarization is a constituent member of a polarizing plate. It is an object of the present invention to provide a liquid crystal display device in which generation of rainbow spots is suppressed even when a polyester film is used as the child protective film.

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 less than 495 nm, 495 nm to less than 600 nm, and 600 nm to 750 nm, respectively, and the half width of each peak is 5 nm or more,
At least one polarizing plate of the two polarizing plates is obtained by laminating a polyester film via an adhesive layer on at least one surface of a polarizer,
The difference between the refractive index of the adhesive layer and the refractive index of the polyester film in a direction parallel to the transmission axis of the polarizer is 0.13 or less.
Liquid crystal display device.
Item 2.
Item 2. The liquid crystal display device according to item 1, wherein the backlight source is a backlight source including a light source that emits excitation light and quantum dots.
Item 3.
Item 3. The liquid crystal display device according to item 1 or 2, wherein the polyester film has a retardation of 1500 to 30000 nm.

  The liquid crystal display device of the present invention has a wide color gamut and can ensure good visibility in which the occurrence of rainbow-like color spots is significantly suppressed at any viewing angle.

(Liquid crystal display device)
In general, the liquid crystal display device includes a rear module, a liquid crystal cell, and a front module in order from the side facing the backlight light source toward 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. Here, the polarizing plate is arranged on the side facing the backlight light source in the rear module, and is arranged on the side (viewing side) displaying the image in the front module. The configuration of the backlight may be an edge light method using a light guide plate or a reflection plate as a constituent member, or a direct type. In addition to the backlight source, the polarizing plate, and the liquid crystal cell, the liquid crystal display device may appropriately include other components 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. Examples of the brightness enhancement film include a reflective polarizing plate that transmits one linearly polarized light and reflects linearly polarized light orthogonal thereto. For example, a DBEF (registered trademark) (Dual Brightness Enhancement Film) series brightness enhancement film manufactured by Sumitomo 3M Limited is preferably used as the reflective polarizing plate. 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.

(Backlight light source)
The liquid crystal display device of the present invention comprises at least a backlight source and a liquid crystal cell disposed between two polarizing plates. The backlight light source has a peak top in each wavelength region of 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. preferable.

  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 750 nm is more preferably 630 nm to 700 nm, and even more preferably 630 nm to 680 mn. If the half-value width of each peak is less than 5 nm, rainbow-like color spots are likely to occur, which is not preferable. The preferable lower limit value of the half width of each peak is 10 nm or more, more preferably 15 nm or more, and further preferably 20 nm or more. From the viewpoint of ensuring an appropriate color gamut, the upper limit of the half width of each peak is preferably 140 nm or less, preferably 120 nm or less, preferably 100 nm or less, more preferably 80 nm or less, and still more preferably. Is 60 nm or less, more preferably 45 nm or less. Here, the half width is the peak width (nm) at half the intensity of the peak intensity at the peak top wavelength.

In the case where a plurality of peaks are present in any one 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 750 nm or less, the following is considered.
When a plurality of peaks are independent peaks, it is preferable that the half width of the peak with the highest peak intensity is in the above range. Furthermore, it is a more preferable aspect that 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. Here, the independent peak has an intensity region that is ½ 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 of intensity that is ½ of the peak intensity, the plurality of peaks are regarded as one peak as a whole. In such a peak having a shape in which a plurality of peaks are overlapped, the peak width (nm) at half the intensity of the highest peak intensity is set as the half width.
Of the plurality of peaks, the peak with the highest peak intensity is defined as the peak top.
Note that the peak having the highest peak intensity in 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 750 nm or less is independent of the peaks of other wavelength regions. Is preferred. In particular, in 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, or the peak having the highest peak intensity in the region of 600 nm or more and 750 nm or less, the intensity is 600 nm or more and 750 nm or less. It is preferable in terms of color clarity that there is a region that is 1/3 of the peak intensity of the peak having the highest peak intensity in the wavelength region.

  The emission spectrum of the backlight source can be measured by using a spectroscope such as a multi-channel spectroscope PMA-12 manufactured by Hamamatsu Photonics.

Specific examples of the backlight light source described above include a light source that emits excitation light and a backlight light source that includes at least quantum dots. In addition, a phosphor-type white LED light source using a phosphor and a blue LED each having an emission peak in the R (red) and G (green) regions by excitation light, and a combination of a three-wavelength white LED light source and a red laser A white LED light source or the like can be exemplified. Among the phosphors, as the red phosphor, for example, a nitride-based phosphor having a basic composition of CaAlSiN ₃ : Eu or the like, a sulfide-based phosphor having a basic composition of CaS: Eu or the like, or Ca ₂ SiO ₄ : Eu Examples thereof include silicate-based phosphors having a basic composition and the like. Among the phosphors, as the green phosphor, for example, a sialon phosphor having a basic composition of β-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 application of quantum dot technology to LCDs is a technology that has attracted attention due to the increasing demand for color gamut expansion in recent years. An LED using a normal white LED as a backlight light source can reproduce colors only about 20% of the spectrum that can be recognized by the human eye. On the other hand, it is said that when a backlight light source composed of a light source that emits excitation light and a light emitting layer including quantum dots is used, it is possible to reproduce colors of 60% or more. Quantum dot technologies that have been put into practical use include QDEF ^™ from Nanosys and Color IQ ^{™ from} QD Vision.

  The quantum dot can be used for a backlight, for example, by providing a layer containing many quantum dots and using this as a light emitting layer. The light emitting layer including quantum dots is configured to include quantum dots in a resin material such as polystyrene, for example, and is a layer that emits emitted light of each color on a pixel basis based on excitation light emitted from a light source. . This light emitting layer is composed of, for example, a red light emitting layer disposed in a red pixel, a green light emitting layer disposed in a green pixel, and a blue light emitting layer disposed in a blue pixel. Based on the excitation light, emission lights having different wavelengths (colors) are generated.

  Examples of the material of such quantum dots include CdSe, CdS, ZnS: Mn, InN, InP, CuCl, CuBr, Si, and the like. The particle size (size in one side direction) of these quantum dots is, for example, 2 About 20 nm. Among the above quantum dot materials, InP is exemplified as a red light emitting material, CdSc is exemplified as a green light emitting material, and CdS is exemplified as a blue light emitting material. In such a light emitting layer, it has been confirmed that the emission wavelength changes by changing the size (particle diameter) of the quantum dots or the composition of the material. The size (particle diameter) and material of the quantum dots are controlled, mixed with a resin material, and applied separately for each pixel.

  As a light source that emits excitation light, a blue LED is used, but laser light such as a semiconductor laser may be used. When the excitation light emitted from the light source passes through the light emitting layer, an emission spectrum having a peak top in each wavelength region of 400 nm to less than 495 nm, 495 nm to less than 600 nm, and 600 nm to 750 nm is generated. At this time, the narrower the half-width of the peak in each wavelength region, the wider the color gamut.However, as the half-width of the peak becomes narrower, the light emission efficiency decreases, so the shape of the emission spectrum has a shape that balances the required color gamut and light emission efficiency. Designed.

(Polarizer)
Of the two polarizing plates arranged in the liquid crystal display device, at least one polarizing plate is a polyester having an adhesive layer on at least one surface of a polarizer in which polyvinyl alcohol (PVA) or the like is dyed with iodine. A film is laminated. Hereinafter, when simply referred to as an adhesive layer, it refers to an adhesive layer existing between a polarizer and a polyester film. It is preferable that a film having no birefringence such as a TAC film, an acrylic film, or a norbornene-based film is laminated on the other surface of the polarizer (a polarizing plate having a three-layer structure). There is no need to laminate a film on the other side (two-layer polarizing plate). In addition, when a polyester film is used as a protective film on both sides of the polarizer, it is preferable that the slow axes of both polyester films are substantially parallel to each other.

  As a result of intensive studies, the present invention has shown that a liquid crystal having a backlight light source in which the half-value width of each peak of the emission spectrum is relatively narrow, as represented by the above-described light source that emits excitation light and the backlight light source including quantum dots. In a display device, even when a polarizing plate using a polyester film is used as a polarizer protective film, the difference between the refractive index of the adhesive layer and the refractive index of the polyester film in a direction parallel to the transmission axis of the polarizer is 0. It has been found that if it is .13 or less, rainbow spots can be suppressed significantly. The mechanism for suppressing the occurrence of rainbow-like color spots according to the above aspect is considered as follows.

  When the oriented polyester film is disposed on one side of the polarizer, 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 when linearly polarized light emitted from the backlight unit or polarizer passes through the oriented polyester film is the difference in refractive index at the interface between the adhesive layer and the oriented polyester film. Found a possibility. When linearly polarized light incident from an oblique direction passes through each interface, a part of the light is reflected due to a difference in refractive index between the interfaces. At this time, since it is considered that the polarization state of the emitted light and the reflected light changes, it is considered that this is one of the factors that cause rainbow-like color spots. For this reason, by reducing the refractive index difference between the adhesive and the oriented polyester film in the polarization direction (transmission axis direction) of incident linearly polarized light, reflection at each interface is suppressed, and rainbow-like color spots are formed. It is thought to be suppressed.

  As described above, in the present invention, as represented by a light source that emits excitation light and a backlight light source including quantum dots, a liquid crystal display device that includes a backlight light source in which the half-value width of each peak of the emission spectrum is relatively narrow. Even if a polarizing plate using a polyester film as a polarizer protective film is used, it becomes possible to have good visibility without generating rainbow-like color spots.

  The difference between the refractive index of the adhesive layer and the refractive index of the polyester film in the direction parallel to the transmission axis of the polarizer is preferably 0.13 or less, preferably 0.12 or less, preferably 0.11 or less. , Preferably 0.10 or less, preferably 0.9 or less, preferably 0.08 or less, preferably 0.07 or less, preferably 0.06 or less, preferably 0.05 or less. The smaller the difference in the refractive index, the more preferable it is because reflection at the polyester film interface can be suppressed and rainbow spots can be suppressed. The lower limit is zero.

  More preferably, the difference between the refractive index of the adhesive layer in the direction parallel to the transmission axis of the polarizer and the refractive index of the polyester film in the direction parallel to the transmission axis of the polarizer is 0.13 or less, more Preferably it is 0.12 or less, more preferably 0.11 or less, more preferably 0.10 or less, more preferably 0.09 or less, more preferably 0.08 or less, more preferably 0.07 or less, more preferably It is 0.06 or less, more preferably 0.05 or less. The smaller the difference in the refractive index, the more preferable it is because reflection at the polyester film interface can be suppressed and rainbow spots can be suppressed. The lower limit is zero.

  The lamination method of the polyester film and the polarizer is not particularly limited, and the fast axis direction of the polyester film and the transmission axis direction of the polarizer are substantially parallel, or the slow axis direction of the polyester film and the transmission of the polarizer. An arrangement in which the axial direction is substantially parallel is preferable. The layers may be laminated with care so that the difference between the refractive index of the adhesive and the refractive index of the polyester film in a direction parallel to the transmission axis of the polarizer is within a preferred range.

  Here, the term “substantially parallel” means that the angle formed by the transmission axis of the polarizer and the fast axis (or slow axis) of the polarizer protective film is preferably −15 ° to 15 °, more preferably −10 °. 10 °, more preferably −5 ° to 5 °, even more preferably −3 ° to 3 °, even more preferably −2 ° to 2 °, and particularly preferably −1 ° to 1 °. In a preferred embodiment, substantially parallel is substantially parallel. Here, “substantially parallel” means that the transmission axis and the fast axis (or slow axis) are parallel to such an extent that a deviation inevitably caused when the polarizer and the protective film are bonded to each other is allowed. Means. 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).

(Polyester film)
The polyester film used for the polarizer protective film preferably has a retardation of 1500 to 30000 nm. If the retardation is in the above range, it is preferable because rainbow spots tend to be reduced more easily. The preferred lower limit of retardation is 3000 nm, the next preferred lower limit is 3500 nm, the more preferred lower limit is 4000 nm, the still more preferred lower limit is 6000 nm, and the still more preferred 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.

  The retardation can also be obtained by measuring the refractive index and thickness in the biaxial direction, or can be obtained using a commercially available automatic birefringence measuring device such as KOBRA-21ADH (Oji Scientific Instruments). 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. As 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. In a complete uniaxial (uniaxial symmetry) film, the ratio of the retardation to the retardation in the thickness direction (Re / Rth) is 2.0. Therefore, 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 ΔNxz and ΔNyz by the film thickness d when the film is viewed from the cross section in the thickness direction.

The refractive index in the fast axis direction of the polyester film is preferably from 1.53 to 1.62. When 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. The upper limit of the refractive index in the fast axis direction of the polyester film is more preferably 1.61 or less, further preferably 1.60 or less, still more preferably 1.59 or less, and particularly preferably 1. 58 or less. The lower limit of the refractive index in the fast axis direction of the polyester film is more preferably 1.54 or more, further preferably 1.55 or more, still more preferably 1.56 or more, and particularly preferably 1. 57 or more.
The refractive index in the slow axis direction of the polyester film is preferably 1.67 or more and 1.75 or less. The upper limit of the refractive index in the slow axis direction of the polyester film is more preferably 1.74 or less, still more preferably 1.73 or less, still more preferably 1.72 or less, and particularly preferably 1. 71 or less. The lower limit of the refractive index of the slow axis of the polyester film is more preferably 1.68 or more. The refractive index can be easily adjusted by a stretching process in a film forming process described later.

  The polarizer protective film made of the polyester film can be used for both the incident light side (light source side) and the outgoing light side (viewing side) polarizing plates. In the polarizing plate arranged on the incident light side, the polarizer protective film made of the polyester film is arranged on both sides, whether it is arranged on the incident light side starting from the polarizer or on the liquid crystal cell side. Although it may be arranged, it is preferably arranged at least on the incident light side. About the polarizing plate arranged on the outgoing light side, 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.

  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. In particular, polyethylene terephthalate has a large intrinsic birefringence. By stretching the film, the refractive index in the fast axis direction (perpendicular to the slow axis direction) can be kept low, and it is relatively easy even if the film is thin. Therefore, it is the most suitable material.

  For the purpose of suppressing deterioration of optical functional dyes such as iodine dyes, 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. In addition, the transmittance | permeability is measured by the perpendicular | vertical method with respect to the plane of a film, and can be measured using a spectrophotometer (for example, Hitachi U-3500 type).

  In order to reduce the transmittance of the polyester film at a wavelength of 380 nm to 20% or less, it is desirable to appropriately adjust the type, concentration and thickness of the ultraviolet absorber. The ultraviolet absorber used in the present invention is a known substance. Examples of 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. Examples of 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 above range. However, from the viewpoint of durability, benzotoazole and cyclic imino ester are particularly preferable. When two or more kinds of ultraviolet absorbers are used in combination, ultraviolet rays having different wavelengths can be absorbed simultaneously, so that the ultraviolet absorption effect can be further improved.

  Examples of the benzophenone ultraviolet absorber, benzotriazole ultraviolet absorber, and acrylonitrile ultraviolet absorber 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′-me Tilphenyl) -5-chlorobenzotriazole, 2- (5-chloro (2H) -benzotriazol-2-yl) -4-methyl-6- (tert-butyl) phenol, 2,2′-methylenebis (4- ( 1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol, etc. Examples of cyclic imino ester UV absorbers include 2,2 ′-(1,4 -Phenylene) bis (4H-3,1-benzoxazinon-4-one), 2-methyl-3,1-benzoxazin-4-one, 2-butyl-3,1-benzoxazin-4-one, Examples thereof include 2-phenyl-3,1-benzoxazin-4-one, but are not particularly limited thereto.

  Moreover, it is also a preferable aspect to contain various additives other than a catalyst in the range which does not prevent the effect of this invention other than an ultraviolet absorber. Examples of 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. Moreover, in order to show high transparency, it is also preferable that a polyester film does not contain a particle | grain substantially. “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 surface of the polyester film that is a polarizer protective film used in the present invention has various functional layers, that is, a hard coat layer, an antiglare layer, an antireflection layer, and the like for the purpose of preventing reflection, suppressing glare, and suppressing scratches. It is also a preferable aspect to provide. When providing various functional layers, the polyester film preferably has an easy adhesion layer on the surface thereof. At that time, from the viewpoint of suppressing interference due to reflected light, it is preferable to adjust the refractive index of the easy-adhesion layer so that it is close to the geometric mean of the refractive index of the functional layer and the refractive index of the polyester film. The refractive index of the easy-adhesion layer can be adjusted by a known method. For example, 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, or the like in order to improve the adhesion to the polarizer.

  In the present invention, in order to improve the adhesion to 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. Is preferred. Here, 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. Examples of these 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. Examples thereof 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 a longitudinal uniaxially stretched film, 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 0.20 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 0.20 g / m ² , blocking resistance may be lowered. When providing an easily bonding layer on both surfaces of a polyester film, 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.

  It is preferable to add particles to the easy-adhesion layer in order to impart easy slipperiness. It is preferable to use particles having an average particle size of 2 μm or less. When the average particle diameter of the particles exceeds 2 μm, the particles easily fall off from the coating layer. As 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.

  Moreover, a well-known method can be used as a method of apply | coating a coating liquid. For example, 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. can be mentioned. Or it can carry out in combination.

  In addition, the measurement of the average particle diameter of said particle | grain is performed with 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.

  The polyester film used as the polarizer protective film can be manufactured according to a general polyester film manufacturing method. For example, 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 film forming conditions of the polyester film will be specifically described. The longitudinal stretching temperature and the transverse stretching temperature are preferably 80 to 135 ° C, more preferably 80 to 130 ° C, and particularly preferably 90 to 120 ° C. In order to orient the film so that the slow axis is in the TD direction, 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. In order to orient the film so that the slow axis is in the MD direction, the longitudinal draw ratio is preferably 2.5 to 6.0 times, particularly preferably 3.0 to 5.5 times. Further, the transverse draw ratio is preferably 1.0 to 3.5 times, particularly preferably 1.0 to 3.0 times.
In order to control the refractive index or retardation in the fast axis direction of the polyester film within the above range, it is preferable to control the ratio of the longitudinal draw ratio and the transverse draw ratio. If the difference between the longitudinal and lateral draw ratios is too small, the refractive index in the fast axis direction of the polyester film tends to exceed 1.62, and it is difficult to increase the retardation. In addition, setting the stretching temperature low is a preferable measure for increasing the retardation. In the subsequent heat treatment, the treatment temperature is preferably from 100 to 250 ° C, particularly preferably from 180 to 245 ° C.

  In order to suppress retardation fluctuation, it is preferable that the thickness unevenness of the film is small. Since the stretching temperature and the stretching ratio greatly affect the thickness variation of the film, it is necessary to optimize the film forming conditions from the viewpoint of the thickness variation. 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 5.0% or less, more preferably 4.5% or less, still more preferably 4.0% or less, and 3.0% or less. Is particularly preferred.

  As described above, in order to control the retardation of the polyester film within a specific range, the stretching ratio, the stretching temperature, and the thickness of the film can be appropriately set. For example, the higher the stretching ratio, the lower the stretching temperature, and the thicker the film, the higher the retardation. Conversely, the lower the stretching ratio, the higher the stretching temperature, and the thinner the film, the lower the retardation. However, when the thickness of the film is increased, the thickness direction retardation tends to increase. Therefore, it is desirable to set the film thickness appropriately within the range described below. In addition to controlling the retardation, it is necessary to set final film forming conditions in consideration of physical properties necessary for processing.

  Although the thickness of a polyester film is arbitrary, the range of 15-300 micrometers is preferable, More preferably, it is the range of 15-200 micrometers. Even in the case of a film having a thickness of less than 15 μm, 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 μm. On the other hand, if the upper limit of the thickness of the polarizer protective film exceeds 300 μm, the thickness of the polarizing plate becomes too thick, which is not preferable. From the viewpoint of practicality as a polarizer protective film, the upper limit of the thickness is preferably 200 μm. A particularly preferable upper limit of the thickness is 100 μm, which is about the same as a general TAC film. In order to control the retardation within the range of the present invention even in the above thickness range, the polyester used as the film substrate is preferably polyethylene terephthalate.

  In addition, as a method of blending the ultraviolet absorber into the polyester film, a known method can be used in combination. For example, 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.

  At this time, 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 economically blend it. As a condition for producing the master batch, it is preferable to use a kneading extruder and to extrude it 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.

  Further, it is preferable that 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. That is, using two or more extruders, 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. In the present invention, it is preferable to perform high-precision filtration during melt extrusion in order to remove foreign substances contained in the raw material polyester that cause optical defects. The filter particle size (initial filtration efficiency 95%) of the filter medium used for high-precision filtration of the molten resin is preferably 15 μm or less. When the filter particle size of the filter medium exceeds 15 μm, removal of foreign matters of 20 μm or more tends to be insufficient.

(Adhesive layer)
A conventionally well-known thing can be used as an adhesive agent for bonding together a polyester film and a polarizer. The lower limit of the refractive index of the adhesive layer is preferably 1.46 or more, more preferably 1.47 or more, and further preferably 1.48 or more. The upper limit of the refractive index of the adhesive layer is preferably 1.59 or less, more preferably 1.56 or less, and still more preferably 1.54 or less.

  Examples of the adhesive include conventionally known aqueous adhesives such as polyvinyl alcohol adhesives such as polyvinyl alcohol and polyvinyl butyral, and vinyl latexes such as polybutyl acrylate. Examples of the polyvinyl alcohol-based adhesive include polyvinyl alcohol, partially saponified polyvinyl acetate, polyvinyl alcohol modified with a carboxyl group or acetoacetyl group, and formalized polyvinyl alcohol.

  A cross-linking agent may be added to the aqueous adhesive. It does not specifically limit as a crosslinking agent, A well-known crosslinking agent can be used. For example, what is used for a polyvinyl alcohol-type adhesive agent can be especially used without a restriction | limiting. For example, alkylene diamines having two alkylene groups and two amino groups such as ethylene diamine, triethylene diamine and hexamethylene diamine; tolylene diisocyanate, hydrogenated tolylene diisocyanate, trimethylolpropane tolylene diisocyanate adduct, triphenylmethane triisocyanate, methylene bis (4-phenylmethane triisocyanate), isophorone diisocyanate and isocyanates such as ketoxime block product or phenol block product thereof; ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin di or triglycidyl ether, 1,6- Hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, di Epoxies such as ricidylaniline and diglycidylamine; monoaldehydes such as formaldehyde, acetaldehyde, propionaldehyde, and butyraldehyde; glyoxal, malondialdehyde, succinaldehyde, glutardialdehyde, maleidialdehyde, phthaldialdehyde, etc. Dialdehydes; methylol urea, methylol melamine, alkylated methylol urea, alkylated methylolated melamine, acetoguanamine, condensates of benzoguanamine and formaldehyde, etc .; aminoformaldehyde resins; zirconium acetate, zirconium nitrate, zirconium carbonate, zirconium hydroxide Zirconium compounds such as zirconium oxychloride; metal glyoxylate (metals include, for example, lithium, sodium, potassium Alkali metals such as magnesium, alkaline earth metals such as magnesium and calcium, transition metals such as titanium, zirconium, chromium, manganese, iron, cobalt, nickel, copper, zinc, aluminum, etc.), glyoxylic acid amine salts (Examples of the amine include glyoxylates such as ammonia, monomethylamine, dimethylamine, and trimethylamine); amino acids or sulfur-containing amino acids having one or more basic groups and one or more acidic groups Acetal compounds such as dimethoxyethanal, diethoxyethanal, dialkoxyethanal; bivalent metals such as sodium, potassium, magnesium, calcium, aluminum, iron, nickel, or salts of trivalent metals and oxides thereof; Can be illustrated. These may be used alone or in combination of two or more. Among these, it is preferable to use an amino acid or a sulfur-containing amino acid having one or more basic groups and one or more acidic groups. The basic group is preferably an amino group, and the acidic group is preferably a carboxyl group or a sulfo group. Examples of the amino acids include glycine, alanine, phenylalanine, valine, leucine, isoleucine, lysine, proline, serine, threonine, tryptophan, histidine, tyrosine, arginine, asparagine, aspartic acid, aspartame, glutamine, glutamic acid, and these amino acids. Examples thereof include a copolymer with (meth) acrylic acid. Examples of the sulfur-containing amino acid include methionine, cysteine, cystine, and taurine. Among these, it is particularly preferable to use a sulfur-containing amino acid having a sulfo group such as taurine. The thing using a metal salt can make the refractive index of an adhesive bond layer high. Moreover, coupling agents, such as a silane coupling agent and a titanium coupling agent, can be used as a crosslinking agent. The amount of the crosslinking agent is, for example, preferably 0.1 to 50 parts by weight, more preferably 100 parts by weight of polyvinyl alcohol resin such as polyvinyl alcohol or polyvinyl butyral, or vinyl latex such as polybutyl acrylate. Is 0.2 to 30 parts by mass, more preferably 0.5 to 20 parts by mass.

  In addition, an active energy ray-curable adhesive is also preferable in recent years. The polarizing plate has a configuration in which a polarizer protective film is laminated on both sides of the polarizer, and at least one of the polarizer protective films is preferably laminated with the polarizer via an active energy ray-curable adhesive. By using the active energy ray-curable composition, even when a low moisture-permeable film is used, adhesion can be achieved and adhesion can be improved. Furthermore, environmental resistance such as wet heat resistance of the polarizing plate can be improved. In particular, by using a solventless active energy ray-curable resin composition, the step of drying the adhesive becomes unnecessary, and thus productivity can be improved.

  As the active energy ray-curable compound contained in the active energy ray-curable composition, conventionally known compounds can be used. Specifically, in addition to the epoxy compound and the oxetane compound, a radical polymerizable monomer such as a (meth) acrylate compound can be used.

(Epoxy compounds and oxetane compounds)
Epoxy compounds include alicyclic epoxy compounds, glycidyl etherified products of aromatic compounds and chain compounds having a hydroxyl group, glycidyl aminated products of compounds having an amino group, and epoxy compounds of chain compounds having a CC double bond. And the like.

  Here, the alicyclic epoxy compound means one having an epoxy group directly in the ring of the saturated cyclic compound and one having a glycidyl ether group or glycidyl group directly in the ring of the saturated cyclic compound. In addition, you may have another epoxy group in the structure.

  An alicyclic epoxy compound having an epoxy group directly in the ring of a saturated cyclic compound is a base having a C—C double bond of a cyclic compound having a C—C double bond in the ring using a peroxide. It can be obtained by epoxidation under sexual conditions.

  The cyclic compound having a C—C double bond in the ring is not particularly limited, and examples thereof include a compound having a cyclopentene ring, a compound having a cyclohexene ring, and a polycyclic compound thereof. The cyclic compound having a C—C double bond in the ring may have a C—C double bond outside the ring. Examples of such a compound include 1-vinyl-3-cyclohexene and monocyclic ring. Examples include limonene, which is a formula monoterpene.

  Further, the alicyclic epoxy compound having an epoxy group directly on the ring of the saturated cyclic compound may be a compound having a structure obtained by dimerizing the epoxidized product obtained above through an appropriate functional group. The bond structure composed of the functional group is not particularly limited, and examples thereof include an ester bond, an ether bond, and a bond by an alkyl group. The dimerized structure of the epoxidized product may have a plurality of these bonds.

  The method for producing an alicyclic epoxy compound having an epoxy group directly on the ring of the saturated cyclic compound varies depending on the individual compound and is not particularly limited. After synthesizing a cyclic compound having a heavy bond in the ring, a method of epoxidizing, and a compound in which a C—C double bond is epoxidized are further reacted with a functional group as described above to obtain a target structure. A synthesis method or the like is employed. From the viewpoint of suppressing side reactions of epoxy groups and the like, usually, a method of epoxidizing after synthesizing a cyclic compound having a C—C double bond in the ring is preferably employed.

  The synthesis of a cyclic compound having a C—C double bond in the ring varies depending on the skeleton of the target epoxy compound and is not particularly limited. As a synthesis example of a dimerized cyclic compound, For example, a method for obtaining 3-cyclohexenylmethyl-3-cyclohexenecarboxylate, which is an ester compound, from 3-cyclohexene-1-carboxaldehyde by a Tishchenko reaction using an appropriate catalyst can be mentioned.

  Further, the ester compound and a dicarboxylic acid compound or an ester thereof, a diol compound or an ester thereof, a polyalkylene glycol or an ester thereof, or a hydroxycarboxylic acid compound or an ester thereof, if necessary, are subjected to an ester exchange reaction. By doing so, a compound having a cyclohexenyl group at both ends is obtained.

  Examples of dicarboxylic acid compounds and esters thereof include oxalic acid, adipic acid, sebacic acid, and dimethyl esters thereof. Examples of the diol compound and its ester include ethylene glycol, diethylene glycol, 1,2-propanediol, polyethylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and dimethyl esters thereof. Can be mentioned. Examples of hydroxycarboxylic acid compounds and esters thereof include lactic acid, 3-hydroxybutyric acid, and citric acid, and dimethyl esters and acetates thereof, and lactide, propiolactone, butyrolactone, and caprolactone. .

  An alicyclic epoxy compound having an epoxy group directly in the ring of the saturated cyclic compound is obtained by epoxidizing the cyclic compound having the C—C double bond thus obtained with a peroxide. be able to. The peroxide is selected according to the individual cyclic compound and acceptable reaction conditions, and is not particularly limited. For example, hydrogen peroxide, peracetic acid, and t-butyl hydroperoxide are used. Etc.

  Specific examples of the alicyclic epoxy compound having an epoxy group directly on the ring of the saturated cyclic compound include, for example, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, 1,2-epoxy- 4-vinylcyclohexane, 1,2-epoxy-1-methyl-4- (1-methylepoxyethyl) cyclohexane, 3,4-epoxycyclohexylmethyl methacrylate, 2,2-bis (hydroxymethyl) -1-butanol 4- (1,2-epoxyethyl) -1,2-epoxycyclohexane adduct, ethylene bis (3,4-epoxycyclohexanecarboxylate), oxydiethylene bis (3,4-epoxycyclohexanecarboxylate), 1,4 -Cyclohexanedimethyl bis (3,4-epoxy Xylcyclohexanecarboxylate), 3- (3,4-epoxycyclohexylmethoxycarbonyl) propyl 3,4-epoxycyclohexanecarboxylate, and the like.

  An alicyclic epoxy compound having a glycidyl ether group or a glycidyl group directly on the ring of a saturated cyclic compound means that an aromatic ring of an aromatic compound having a hydroxyl group, which will be described later, is pressed under pressure in the presence of a catalyst. A compound obtained by selectively performing a hydrogenation reaction, a glycidyl etherified product of a saturated cyclic compound having a hydroxyl group, and an epoxidized product of a saturated cyclic compound having a vinyl group.

  The glycidyl etherified product of an aromatic compound having a hydroxyl group to be hydrogenated is not particularly limited, and examples thereof include glycidyl etherified products of bisphenol A and oligomers thereof, and glycidyl etherified products of bisphenol F and oligomers thereof. Examples include the body.

  The glycidyl etherified product of a saturated cyclic compound having a hydroxyl group is not particularly limited, and examples thereof include 1,4-cyclohexanedimethanol diglycidyl ether.

  The epoxidized product of the saturated cyclic compound having a vinyl group is not particularly limited. For example, 1,3-bis (epoxyethyl) hexane, 1,2,4-tris (epoxyethyl) hexane, and 2 , 4-bis (epoxyethyl) -1-vinylcyclohexane and the like.

  Among the alicyclic epoxy compounds described above, 3,4-epoxy has good cured product characteristics for improving the durability of the polarizing plate, or has moderate curability and is available at a relatively low price. A hydrogenated product of cyclohexylmethyl 3,4-epoxycyclohexanecarboxylate and a glycidyl etherified product of bisphenol A is preferable, and 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate is more preferable.

  These alicyclic epoxy compounds may be used alone or in combination of two or more.

  The hue of the active energy ray-curable composition containing the alicyclic epoxy compound is preferably 5 or less, more preferably 3 or less, and even more preferably 1 or less in terms of Gardner chromaticity of the active energy ray-curable composition before curing. When the hue exceeds 5, the hue of the polarizing plate may be affected by the coloring of the adhesive layer.

  The glycidyl etherified product of an aromatic compound and a chain compound having a hydroxyl group is obtained by addition condensation of a compound such as epichlorohydrin to the hydroxyl group under alkaline conditions. Examples thereof include bisphenol type epoxy resins, polyaromatic ring type epoxy resins, and alkylene glycol type epoxy resins.

  Examples of the bisphenol type epoxy resin include glycidyl etherified products of bisphenol A and oligomers thereof, glycidyl etherified products of bisphenol F and oligomers thereof, and 3,3 ′, 5,5′-methyl-4,4′-biphenol. Glycidyl etherified products and oligomers thereof.

  Examples of the polyaromatic epoxy resin include glycidyl etherified products of phenol novolac resins, glycidyl etherified products of cresol novolac resins, glycidyl etherified products of phenol aralkyl resins, glycidyl etherified products of naphthol aralkyl resins, and phenol dicyclopentadiene. Examples thereof include glycidyl etherified products of resins. Furthermore, a glycidyl etherified product of trihydroxyphenylmethane and an oligomer thereof, and a glycidyl etherified product of trisphenol PA and an oligomer thereof are also included.

  Examples of the alkylene glycol type epoxy resin include glycidyl etherified product of ethylene glycol, glycidyl etherified product of diethylene glycol, glycidyl etherified product of 1,4-butanediol, and glycidyl etherified product of 1,6-hexanediol. It is done.

  The glycidyl aminated product of a compound having an amino group is obtained by addition condensation of a compound such as epichlorohydrin to the amino group under basic conditions. The compound having an amino group may have a hydroxyl group at the same time. For example, glycidyl amination product of 1,3-phenylenediamine and oligomer thereof, glycidyl amination product and oligomer of 1,4-phenylenediamine, glycidyl amination and glycidyl etherification product of 3-aminophenol and oligomer thereof And glycidyl amination and glycidyl etherification products of 4-aminophenol and oligomers thereof.

  An epoxidized product of a chain compound having a CC double bond is an epoxidation of a CC compound of a chain compound having a CC double bond under basic conditions using a peroxide. It is obtained by making it.

  The chain compound having a C—C double bond is not particularly limited, and examples thereof include butadiene, polybutadiene, isoprene, pentadiene, and hexadiene.

  These epoxy compounds and oligomers thereof may be used alone or in combination of two or more.

  Such epoxy compounds can be easily obtained as commercial products. For example, “Celoxide”, “Cyclomer” (manufactured by Daicel Chemical Industries, Ltd.) and “Syracure” Dow Chemical Co., Ltd., “Epicoat” (manufactured by Japan Epoxy Resin Co., Ltd.), “Epiclon” (manufactured by DIC Corporation), “Epototo” (manufactured by Toto Kasei Co., Ltd.), “Adeka Resin” (manufactured by ADEKA Corporation), “ “Denacol” (manufactured by Nagase ChemteX Corporation), “Dow Epoxy” (manufactured by Dow Chemical Company), “Tepic” (manufactured by Nissan Chemical Industries, Ltd.), and the like.

  The epoxy equivalent of the epoxy compound is usually 30 to 2000 g / eq, preferably 50 to 1500 g / eq, and more preferably 70 to 1000 g / eq. When the epoxy equivalent is less than 30 g / eq, the flexibility of the first adhesive layer may be lowered or the adhesive strength may be lowered. On the other hand, if it exceeds 2000 g / eq, the curing rate may decrease, or the rigidity and strength required for the cured adhesive layer may be insufficient. This epoxy equivalent is a value measured according to JIS K 7236 (ISO 3001). If the epoxy compound is a high purity monomer, the theoretical amount can be calculated from the molecular weight.

  As the active energy ray-curable compound, by using a plurality of epoxy compounds, for example, an alicyclic epoxy compound and an epoxy compound other than the alicyclic epoxy compound, adhesion between the polarizing film and the stretched polyester film can be improved. Can be improved.

  An oxetane compound can be used as the active energy ray-curable compound. The oxetane compound can improve the curing rate of the active energy ray-curable composition. The oxetane compound is a compound having an oxetane ring and is not particularly limited as long as it is active energy ray curable. For example, 1,4-bis {[(3-ethyloxetane-3-yl) Methoxy] methyl} benzene, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, bis (3-ethyl-3-oxetanylmethyl) ether, 3-ethyl-3- (phenoxymethyl) oxetane, 3-ethyl -3- (cyclohexyloxymethyl) oxetane, phenol novolac oxetane, 1,3-bis [(3-ethyloxetane-3-yl) methoxy] benzene, and the like.

  Such oxetane compounds can be easily obtained as commercial products. For example, “Aron Oxetane” (manufactured by Toagosei Co., Ltd.) and “ETERRNACOLL” (manufactured by Ube Industries, Ltd.) are available under the trade names. Etc.

  The active energy ray-curable composition containing an epoxy compound or an oxetane compound is preferably blended with a cationic polymerization initiator in order to be cured by active energy rays. The cationic polymerization initiator generates a cationic species or a Lewis acid by irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, and electron beams, and initiates a polymerization reaction of an epoxy group and an oxetane.

  This cationic polymerization initiator is preferably provided with latency. By providing the potential, the pot life of the active energy ray-curable composition used in the present invention is prolonged, and the workability is also improved.

  The compound that generates a cation species or a Lewis acid upon irradiation with active energy rays is not particularly limited, and examples thereof include onium salts such as aromatic diazonium salts, aromatic iodonium salts, aromatic sulfonium salts, and iron. -An allene complex etc. can be mentioned.

  Examples of the aromatic diazonium salt include benzenediazonium hexafluoroantimonate, benzenediazonium hexafluorophosphate, and benzenediazonium hexafluoroborate.

  Examples of the aromatic iodonium salt include diphenyliodonium tetrakis (pentafluorophenyl) borate, diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, and di (4-nonylphenyl) iodonium hexafluorophosphate.

  Examples of the aromatic sulfonium salt include triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetrakis (pentafluorophenyl) borate, diphenyl [4- (phenylthio) phenyl] sulfonium hexafluoroantimonate, 4,4′-bis [diphenylsulfonio] diphenyl sulfide bishexafluorophosphate, 4,4′-bis [di (β-hydroxyethoxy) phenylsulfonio] diphenyl sulfide bishexafluoroantimonate, 4,4′-bis [Di (β-hydroxyethoxy) phenylsulfonio] diphenyl sulfide bishexafluorophosphate, 7- [di (p-toluyl) sulfoni ] -2-Isopropylthioxanthone hexafluoroantimonate, 7- [di (p-toluyl) sulfonio] -2-isopropylthioxanthone tetrakis (pentafluorophenyl) borate, 4-phenylcarbonyl-4'-diphenylsulfonio-diphenyl sulfide hexa Fluorophosphate, 4- (p-tert-butylphenylcarbonyl) -4'-diphenylsulfonio-diphenyl sulfide hexafluoroantimonate, and 4- (p-tert-butylphenylcarbonyl) -4'-di (p-toluyl) ) Sulfonio-diphenyl sulfide tetrakis (pentafluorophenyl) borate and the like.

  Examples of iron-allene complexes include xylene-cyclopentadienyl iron (II) hexafluoroantimonate, cumene-cyclopentadienyl iron (II) hexafluorophosphate, and xylene-cyclopentadienyl iron (II)- And tris (trifluoromethylsulfonyl) methanide.

  These cationic polymerization initiators may be used alone or in combination of two or more. Among them, aromatic sulfonium salts are particularly preferably used because they have ultraviolet absorption characteristics even in a wavelength region of 300 nm or more, and therefore can provide a cured layer having excellent curability and good mechanical strength and adhesive strength. .

  The compounding quantity of a cationic polymerization initiator is 0.5-20 weight part normally with respect to a total of 100 weight part of an active energy ray hardening compound, and 1-15 weight part is preferable. If the amount is less than 0.5 parts by weight, curing may be insufficient, and the mechanical strength and adhesive strength of the cured product layer may be reduced. On the other hand, when the amount exceeds 20 parts by weight, the ionic substance in the cured product layer is increased, so that the hygroscopic property of the cured product layer is increased, and the durability performance of the obtained polarizing plate may be lowered.

  These cationic polymerization initiators can be easily obtained from commercial products, for example, “Kayarad” (manufactured by Nippon Kayaku Co., Ltd.), “Syracure” (manufactured by Union Carbide), Photoacid generator “CPI” (manufactured by San Apro Co., Ltd.), photoacid generators “TAZ”, “BBI”, “DTS” (manufactured by Midori Chemical Co., Ltd.), “Adekaoptomer” (manufactured by ADEKA Corporation) And “RHODORSIL” (manufactured by Rhodia).

(Radically polymerizable monomers such as (meth) acrylate compounds)
Examples of the radical polymerizable monomer include acrylate compounds, methacrylate compounds (hereinafter also referred to as (meth) acrylates in the meaning including both acrylates and methacrylates), allyl urethane compounds, unsaturated polyester compounds, and styrene compounds. It is done. (Meth) acrylate is preferred because it is easily available and easy to handle. As (meth) acrylate, epoxy (meth) acrylate, urethane (meth) acrylate, (poly) ester (meth) acrylate, (poly) ether (meth) acrylate, alcohol (meth) acrylate, other (meth) An acrylate is mentioned.

  The epoxy (meth) acrylate exemplified as the above (meth) acrylate compound is one type or two or more types of epoxy resin and acrylic acid or methacrylic acid (hereinafter also referred to as (meth) acrylic acid in the meaning of including both). And an ester compound. The ester-derived epoxy resin is not particularly limited, and has one or more epoxy groups in the molecule, such as aromatic epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, epoxy novolac resin, etc. Can be used.

  The urethane (meth) acrylate is a hydroxyl group containing an ester compound of (meth) acrylic acid and one or more (poly) ester polyols, (poly) ether polyols, polyols such as polyhydric alcohols, and the like ( (Meth) acrylates obtained by reacting (meth) acrylates with one or more (poly) isocyanate compounds; one or more (poly) ester polyols, (poly) ether polyols, many It is an ester compound having a urethane bond, such as (meth) acrylate obtained by reacting a polyol such as a monohydric alcohol, a hydroxyl group-containing (meth) acrylate and an isocyanate.

  Examples of the polyhydric alcohol for deriving the (poly) ester polyol include 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, neopentyl glycol, polyethylene glycol, and polypropylene. Examples include glycol, polybutylene glycol, trimethylolpropane, glycerin, pentaerythritol, and dipentaerythritol. Examples of the polycarboxylic acid from which the (poly) ester polyol is derived include adipic acid, terephthalic acid, phthalic anhydride, trimellitic acid, trimesic acid, and the like.

  Examples of the (poly) ether polyol include those obtained by adding an alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide to the polyhydric alcohol described above. Examples of the (poly) isocyanate compound include monovalent or divalent isocyanates, and divalent or higher isocyanates are preferred.

  Divalent or higher isocyanates include 2,4- and / or 2,6-tolylene diisocyanate, diphenylmethane-4,4′-diisocyanate, p-phenylene diisocyanate, xylylene diisocyanate, 1,5-naphthylene diisocyanate, 3 , 3′-dimethyldiphenyl-4,4′-diisocyanate, dianisidine diisocyanate, tetramethylxylylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, trans and / or cis-1,4-cyclohexane diisocyanate, Norbornene diisocyanate, 1,6-hexamethylene diisocyanate, 2,2,4 and / or (2,4,4) -trimethylhexamethylene diisocyanate, lysine Isocyanate, triphenylmethane triisocyanate, 1-methyl-benzol-2,4,6-triisocyanate, dimethyl triphenylmethane tetra isocyanate.

  The (poly) ester (meth) acrylate is an ester compound of (poly) ester having (one) or two or more hydroxyl groups in the molecule and (meth) acrylic acid. (Poly) ester having one or more hydroxyl groups in the molecule is an ester compound of one or more polyhydric alcohols and one or more monocarboxylic acids or polycarboxylic acids. Is mentioned.

  Examples of the polyhydric alcohol for deriving a (poly) ester having one or two or more hydroxyl groups in the molecule include those described above, and examples of the monocarboxylic acid include formic acid, acetic acid, and propionic acid. , Butyric acid, isobutyric acid, valeric acid, caproic acid, caprylic acid, 2-ethylhexanoic acid, benzoic acid and the like. Examples of the polycarboxylic acid include the same compounds as those described above.

  Moreover, (poly) ether (meth) acrylate is an ester compound of (poly) ether and (meth) acrylic acid having one or more hydroxyl groups in the molecule. (Poly) ether having 1 or 2 or more hydroxyl groups in the molecule, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, or one or more alkylene oxides added to polyhydric alcohol And the like obtained by doing so. Examples of the polyhydric alcohol and alkylene oxide include the same compounds as those described above. Specifically, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, ethylene oxide modified trimethylolpropane tri (meth) acrylate, propylene Examples thereof include oxide-modified trimethylolpropane tri (meth) acrylate and dipentaerythritol hexa (meth) acrylate.

  The (meth) acrylates of alcohols are ester compounds of alcohols (particularly aliphatic alcohols or aromatic alcohols) having one or more hydroxyl groups in the molecule and (meth) acrylates. For example, 2-ethylhexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, isoamyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isooctyl (meth) Acrylate, tetrahydrofurfuryl (meth) acrylate, isobornyl (meth) acrylate, benzyl (meth) acrylate, 1,3-butanediol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, neopentyl glycol di (Meth) acrylate, 1,6-hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate and the like.

  Other acrylates include ε-caprolactone-modified dipentaerythritol hexa (meth) acrylate, fluorene derivative di (meth) acrylate, carbazole derivative di (meth) acrylate, and the like.

  The above radical polymerizable monomer can be used to adjust the curing rate. In addition, when using a radically polymerizable monomer, photoradical polymerization initiator is used at least.

  Examples of the photo radical polymerization initiator include ketone compounds such as acetophenone compounds, benzyl compounds, benzophenone compounds, and thioxanthone compounds.

  Examples of the acetophenone compound include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 4′-isopropyl-2-hydroxy-2-methylpropiophenone, 2-hydroxymethyl- 2-methylpropiophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, p-dimethylaminoacetophenone, P-tertiarybutyldichloroacetophenone, p-tertiarybutyltrichloroacetophenone, p-azidoben Salacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanone-1, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) ) -Butanone-1, benzo , Benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether and the like. Examples of the benzyl compound include benzyl and anisyl. Examples of the benzophenone compound include Examples include benzophenone, methyl o-benzoylbenzoate, Michler's ketone, 4,4′-bisdiethylaminobenzophenone, 4,4′-dichlorobenzophenone, 4-benzoyl-4′-methyldiphenyl sulfide, and the thioxanthone compound includes thioxanthone. , 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, 2,4-diethylthioxanthone and the like.

  These radical photopolymerization initiators can be used alone or in combination of two or more according to the desired performance, and preferably 0.05 to 10% by mass with respect to the radical polymerizable monomer. More preferably, it is blended in an amount of 0.1 to 10% by mass. When the blending amount of the radical photopolymerization initiator with respect to the radical polymerizable monomer is 0.05% by mass or more, the curing of the photocurable adhesive can be progressed more favorably, and when it is 10% by mass or less, the light The physical strength of the adhesive layer formed by curing the curable adhesive is good.

  The total amount of chlorine contained in the active energy ray-curable composition is preferably in the range of 0.1 ppm to 15000 ppm, more preferably in the range of 0.5 ppm to 2000 ppm, and still more preferably in the range of 1.0 to 1000 ppm. If the total amount of chlorine contained in the active energy ray-curable composition is less than 0.1 ppm, the curing rate of the composition may be extremely slow. On the other hand, if it exceeds 15000 ppm, the coating device may corrode or the metal parts of the liquid crystal panel may corrode due to the influence of chlorine. This total chlorine amount is a value measured in accordance with JIS K 7243-3 (ISO 21627-3).

  Examples of the active energy ray used include X-rays having a wavelength of 1 pm to 10 nm, ultraviolet rays having a wavelength of 10 to 400 nm, and visible rays having a wavelength of 400 to 800 nm. Among these, ultraviolet rays are preferably used in terms of ease of use, ease of adjustment of the active energy ray-curable composition and its stability, and its curing performance.

  The active energy ray-curable composition used in the present invention is a curable composition that is solidified (cured) by irradiation with active energy rays and gives an adhesive force to films that sandwich the cured product layer.

  Although the light source to be used is not particularly limited, for example, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excitation mercury lamp, having a light emission distribution at a wavelength of 400 nm or less, And metal halide lamps.

The irradiation intensity is determined by the active energy ray-curable composition and the irradiation time, and is not particularly limited. For example, the irradiation intensity in the wavelength region effective for activating the initiator is 0.1. It is preferable that it is -1000mW / cm < ² >. When the light irradiation intensity to the active energy ray-curable composition is less than 0.1 mW / cm ² , the curing reaction time becomes long, that is, it does not cure unless a long irradiation time is applied, which is disadvantageous for improving productivity. There is a case. Moreover, when it exceeds 1000 mW / cm ² , yellowing of the active energy ray-curable composition or deterioration of the polarizing film is caused by heat radiated from the lamp and heat generation during polymerization of the active energy ray-curable composition. There is.

The irradiation time is determined by the active energy ray-curable composition and the irradiation intensity and is not particularly limited. For example, the integrated light amount expressed as the product of the irradiation intensity and the irradiation time is 10 to 5 It is preferably set to be 000 mJ / cm ² . When the integrated light quantity to the active energy ray-curable composition is less than 10 mJ / cm ² , the generation of active species derived from the initiator is not sufficient, and the resulting adhesive layer may be insufficiently cured. On the other hand, if it exceeds 5,000 mJ / cm ² , the irradiation time becomes very long, which may be disadvantageous for improving productivity.

  The active energy ray-curable composition used in the present invention can be used in combination with a photosensitizer as necessary. By using a photosensitizer, the reactivity is improved, and the mechanical strength and adhesive strength of the cured product layer can be improved.

  The photosensitizer is not particularly limited, and examples thereof include carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo and diazo compounds, halogen compounds, and photoreductive dyes. .

  Examples of the carbonyl compound include benzoin derivatives such as benzoin methyl ether, benzoin isopropyl ether, and α, α-dimethoxy-α-phenylacetophenone; anthracene compounds such as 9,10-dibutoxyanthracene; benzophenone, 2,4 Benzophenone derivatives such as -dichlorobenzophenone, methyl o-benzoylbenzoate, 4,4'-bis (dimethylamino) benzophenone, and 4,4'-bis (diethylamino) benzophenone; of 2-chloroanthraquinone and 2-methylanthraquinone Anthraquinone derivatives such as; acridone derivatives such as N-methylacridone and N-butylacridone; acetophenone derivatives such as α, α-diethoxyacetophenone; And fluorenone derivatives.

  Examples of the organic sulfur compound include thioxanthone derivatives such as 2-chlorothioxanthone and 2-isopropylthioxanthone. Other examples include benzyl compounds and uranyl compounds.

  The photosensitizers may be used alone or in combination. The photosensitizer is preferably contained in the range of 0.1 to 20 parts by weight when the active energy ray-curable composition is 100 parts by weight.

  Various additives can be blended with the active energy ray-curable composition used in the present invention as long as the effects of the present invention are not impaired. Examples of various additives include ion trapping agents, antioxidants, chain transfer agents, sensitizers, tackifiers, thermoplastic resins, fillers, flow regulators, plasticizers, and antifoaming agents. It is done.

  Examples of the ion trapping agent include inorganic compounds such as powdered bismuth-based, antimony-based, magnesium-based, aluminum-based, calcium-based, titanium-based, and mixed systems thereof. Examples of the antioxidant include hindered phenol antioxidants.

  Examples of the thermoplastic resin include acrylic resin, urethane resin, and polyester resin.

  Although the method of forming the layer (adhesive layer before hardening) which consists of the active energy ray curable composition shown above on a polarizing film or a polarizer protective film is not specifically limited, For example, a polarizing film Or the method of apply | coating this composition on a polarizer protective film, the method of spraying this composition, the method of bonding this composition previously formed in the film form, etc. are employ | adopted. Among them, the method of applying the composition or the method of pasting the film-like composition is preferable because of relatively high uniformity of the coating film, and the method of applying the composition is more highly productive. preferable.

  Although it does not specifically limit as a coating method, For example, various coating systems, such as a doctor blade, a wire bar, a die coater, a comma coater, and a gravure coater, are employ | adopted.

  The thickness of the applied adhesive layer before curing is usually 0.1 to 20 μm, preferably 0.2 to 10 μm, and more preferably 0.5 to 5 μm. When the thickness is less than 0.1 μm, the adhesion between the polarizing film and the polarizer protective film due to the cured adhesive layer may be insufficient. Further, if the thickness exceeds 20 μm, the curing of the adhesive layer may not proceed sufficiently, or even if cured, the flexibility of the film may deteriorate due to the thickness, or the effect of thinning may not be obtained. .

  The thickness of the adhesive layer is preferably 10 μm or less, more preferably 5 μm or less, and even more preferably 3 μm or less. The lower limit is preferably 5 nm or more, more preferably 10 nm or more, and further preferably 20 nm or more.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited by the following examples, and may be implemented with appropriate modifications within a scope that can meet the gist of the present invention. These are all included in the technical scope of the present invention. In addition, the evaluation method of the physical property in the following examples is as follows.

(1) Refractive index of polyester film Using a molecular orientation meter (manufactured by Oji Scientific Instruments, MOA-6004 type molecular orientation meter), the slow axis direction of the film is obtained, and the slow axis direction is the long side of the sample for measurement. A 4 cm × 2 cm rectangle was cut out so as to be parallel to each other and used as a measurement sample. For this sample, 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).

(2) Retardation (Re)
Retardation is a parameter defined by the product (ΔNxy × d) of the biaxial refractive index anisotropy (ΔNxy = | Nx−Ny |) and the film thickness d (nm) on the film. Yes, it is a scale showing optical isotropy and anisotropy. The biaxial refractive index anisotropy (ΔNxy) was determined by the following method. Using a molecular orientation meter (MOA-6004 type molecular orientation meter, manufactured by Oji Scientific Instruments Co., Ltd.), the slow axis direction of the film is obtained, and 4 cm so that the slow axis direction is parallel to the long side of the measurement sample. A rectangle of × 2 cm was cut out and used as a measurement sample. For this 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. The absolute value (| Nx−Ny |) of the biaxial refractive index difference was determined as a refractive index anisotropy (ΔNxy), 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 (ΔNxy × d) of refractive index anisotropy (ΔNxy) and film thickness d (nm).

(3) Thickness direction retardation (Rth)
Thickness direction retardation is obtained by multiplying two birefringences ΔNxz (= | Nx−Nz |) and ΔNyz (= | Ny−Nz |) by film thickness d when viewed from the cross section in the film thickness direction. It is a parameter which shows the average of retardation obtained. Thickness direction retardation (Rth) is obtained by calculating Nx, Ny, Nz and film thickness d (nm) by the same method as the retardation measurement, and calculating the average value of (ΔNxz × d) and (ΔNyz × d). )

(4) Measurement of emission spectrum of backlight light source The liquid crystal display device used in each example includes BRAVIA KDL-40W920A manufactured by Sony (a liquid crystal display having a light source that emits excitation light and a backlight light source including quantum dots). Apparatus). When the emission spectrum of the backlight source of this liquid crystal display device was measured using a multi-channel spectrometer PMA-12 manufactured by Hamamatsu Photonics, emission spectra having peak tops in the vicinity of 450 nm, 528 nm, and 630 nm were observed. The half width of was 17 nm to 34 nm. The exposure time for spectrum measurement was 20 msec.

(5) Iridescent Observation The liquid crystal display device obtained in each example was visually observed in the dark from the front and oblique directions, and the presence or absence of the occurrence of irido was determined as follows.

○: Iridescent is not observed △: Iridescent is slightly observed ×: Iridescent is observed XX: Iridescent is remarkably observed

(6) Refractive Index of Adhesive Layer After applying an adhesive to a glass plate, it was solidified under the same conditions as actual processing to produce a coating film of about several μm. The coating film was peeled from the glass plate, and the refractive index was measured with an Abbe refractometer (manufactured by Atago Co., Ltd., NAR-1T SOLID, measurement wavelength 589 nm).

(Production Example 1-Polyester A)
When the temperature of the esterification reactor was raised to 200 ° C., 86.4 parts by mass of terephthalic acid and 64.6 parts by mass of ethylene glycol were charged and 0.017 parts by mass of antimony trioxide as a catalyst while stirring. 0.064 parts by mass of magnesium acetate tetrahydrate and 0.16 parts by mass of triethylamine were charged. Next, the pressure was raised and the pressure esterification reaction was carried out under the conditions of gauge pressure 0.34 MPa and 240 ° C., then the esterification reaction can was returned to normal pressure, and 0.014 parts by mass of phosphoric acid was added. Furthermore, it heated up to 260 degreeC over 15 minutes, and 0.012 mass part of trimethyl phosphate was added. Then, after 15 minutes, dispersion treatment was performed with a high-pressure disperser, and after 15 minutes, the obtained esterification reaction product was transferred to a polycondensation reaction can and subjected to polycondensation reaction at 280 ° C. under reduced pressure.

  After completion of the polycondensation reaction, it is filtered through a NASRON filter with a 95% cut diameter of 5 μm, extruded into a strand from a nozzle, and cooled and solidified using cooling water that has been filtered (pore diameter: 1 μm or less) in advance. And cut into pellets. 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).)

(Production Example 2-Polyester B)
10 parts by weight of a dried UV absorber (2,2 ′-(1,4-phenylene) bis (4H-3,1-benzoxazinon-4-one), PET (A) containing no particles (inherent viscosity Was 0.62 dl / g) and 90 parts by mass were mixed, and a polyethylene terephthalate resin (B) containing an ultraviolet absorber was obtained using a kneading extruder (hereinafter abbreviated as PET (B)).

(Production Example 3-Adjustment of Adhesiveness Modification Coating Solution)
A transesterification reaction and a polycondensation reaction are carried out by a conventional method, and as a dicarboxylic acid component (based on the whole 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. Next, 51.4 parts by mass of water, 38 parts by mass of isopropyl alcohol, 5 parts by mass of n-butyl cellosolve, 0.06 parts by mass of nonionic surfactant were mixed and then heated and stirred. After adding 5 parts by mass of a water-dispersible sulfonic acid metal base-containing copolymer polyester resin and continuing to stir until the resin is no longer agglomerated, the resin water dispersion is cooled to room temperature to obtain a solid content concentration of 5.0% by mass. A uniform water-dispersible copolymerized polyester resin liquid was obtained. Furthermore, after dispersing 3 parts by mass of aggregated silica particles (Silicia 310, manufactured by Fuji Silysia Co., Ltd.) in 50 parts by mass of water, 99.46 parts by mass of the water-dispersible copolyester resin liquid was mixed with 0.54 parts by mass of the aqueous dispersion was added, and 20 parts by mass of water was added with stirring to obtain an adhesive modified coating solution.

(Polarizer 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. . After filtering these two kinds of polymers with a filter medium made of a sintered stainless steel (nominal filtration accuracy of 10 μm particles 95% cut), laminating them in a two-kind / three-layer confluence block, and extruding them into a sheet form from a die, The film was wound around a casting drum having a surface temperature of 30 ° C. using an electrostatic application casting method, and then cooled and solidified to produce an unstretched film. At this time, the discharge amount of each extruder was adjusted so that the thickness ratio of the I layer, the II layer, and the III layer was 10:80:10.

Next, after applying the adhesive property-modifying coating solution on the both sides of this unstretched PET film by a reverse roll method so that the coating amount after drying was 0.08 g / m ² , the coating 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. Next, while maintaining the width stretched in the width direction, it 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 uniaxially stretched PET film having a film thickness of about 100 μm. It was. Re of the obtained film was 10300 nm, Rth was 12350 nm, Re / Rth was 0.83, Nx = 1.588, Ny = 1.661.

(Polarizer protective film 2)
A film was formed in the same manner as the polarizer protective film 1 except that the thickness of the unstretched film was changed by changing the line speed, to obtain a uniaxially stretched PET film having a film thickness of about 80 μm. The obtained film had Re of 8080 nm, Rth of 9960 nm, Re / Rth of 0.81, Nx = 1.589, and Ny = 1.690.

(Polarizer protective film 3)
A film was formed in the same manner as the polarizer protective film 1 except that the thickness of the unstretched film was changed by changing the line speed to obtain a uniaxially stretched PET film having a film thickness of about 60 μm. Re of the obtained film was 6060 nm, Rth was 7470 nm, Re / Rth was 0.81, Nx = 1.589, and Ny = 1.690.

(Polarizer protective film 4)
A film was formed in the same manner as the polarizer protective film 1 except that the line speed was changed and the thickness of the unstretched film was changed to obtain a uniaxially stretched PET film having a film thickness of about 40 μm. Re of the obtained film was 4160 nm, Rth was 4920 nm, Re / Rth was 0.85, Nx = 1.487, Ny = 1.661.

(Polarizer protective film 5)
An unstretched film produced by the same method as that for the polarizer protective film 1 is heated to 105 ° C. using a heated roll group and an infrared heater, and then 1.5 rolls in the traveling direction with a roll group having a difference in peripheral speed. After double stretching, the film was introduced into a hot air zone at a temperature of 130 ° C. and stretched 4.0 times in the width direction, and a biaxially stretched PET film having a film thickness of about 100 μm was obtained in the same manner as the polarizer protective film 1. Re of the obtained film was 7820 nm, Rth was 13890 nm, Re / Rth was 0.56, Nx = 1.608, Ny = 1.686.

(Polarizer protective film 6)
An unstretched film produced by the same method as that of the polarizer protective film 1 is heated to 105 ° C. using a heated roll group and an infrared heater, and then 2.0% in the traveling direction by a roll group having a difference in peripheral speed. After being double-stretched, it was introduced into a hot air zone at a temperature of 135 ° C. and stretched 4.0 times in the width direction, and a biaxially stretched PET film having a film thickness of about 100 μm was obtained in the same manner as the polarizer protective film 1. The obtained film had Re of 6400 nm, Rth of 14600 nm, Re / Rth of 0.44, Nx = 1.617, and Ny = 1.661.

(Polarizer protective film 7)
An unstretched film produced by the same method as that of the polarizer protective film 1 is heated to 105 ° C. using a heated roll group and an infrared heater, and then 2.8 in the traveling direction with a roll group having a difference in peripheral speed. After being double-stretched, it was introduced into a hot air zone at a temperature of 140 ° C. and stretched 4.0 times in the width direction, and a biaxially stretched PET film having a film thickness of about 100 μm was obtained in the same manner as the polarizer protective film 1. Re of the obtained film was 5400 nm, Rth was 15900 nm, Re / Rth was 0.34, Nx = 1.631, Ny = 1.485.

(Polarizer protective film 8)
An unstretched film produced by the same method as that for the polarizer protective film 1 is heated to 105 ° C. using a heated roll group and an infrared heater, and then 3.3 rolls in the running direction with a roll group having a difference in peripheral speed. After being double-stretched, it was introduced into a hot air zone at a temperature of 140 ° C. and stretched 4.0 times in the width direction, and a biaxially stretched PET film having a film thickness of about 100 μm was obtained in the same manner as the polarizer protective film 1. Re of the obtained film was 4800 nm, Rth was 16700 nm, Re / Rth was 0.29, Nx = 1.640, and Ny = 1.688.

  A liquid crystal display device was prepared using the polarizer protective films 1 to 8 as described later.

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 phase advance axis of the film are parallel to each other, and a TAC film (FUJIFILM Corporation) on the opposite side. Manufactured, with a thickness of 80 μm) to make a polarizing plate 1. The polarizer, the polarizer protective film, and the TAC film were bonded together via an aqueous solution (polyvinyl alcohol-based adhesive) composed of 4 parts of polyvinyl alcohol, 1 part of melamine, and 95 parts of water, and dried at 60 ° C. for 3 minutes. The refractive index of this polyvinyl alcohol-based adhesive was 1.490.
The polarizing plate on the viewing side of BRAVIA KDL-40W920A (a liquid crystal display device having a light source that emits excitation light and a backlight light source including quantum dots) manufactured by Sony, the polyester film is opposite to the liquid crystal (distal) Thus, a liquid crystal display device was produced by replacing the polarizing plate 1. In addition, it replaced so that the direction of the transmission axis of the polarizing plate 1 might become the same as the direction of the transmission axis of the polarizing plate before replacement.

(Example 2)
A polarizer protective film 2 is attached to one side of a polarizer made of PVA and iodine so that the transmission axis of the polarizer and the phase advance axis of the film are parallel to each other, and a TAC film (Fuji Film Co., Ltd.) on the opposite side. Manufactured, with a thickness of 80 μm) to make a polarizing plate 2. The polarizer, the polarizer protective film, and the TAC film were bonded together via an aqueous solution (polyvinyl alcohol-based adhesive) composed of 4 parts of polyvinyl alcohol, 1 part of melamine, and 95 parts of water, and dried at 60 ° C. for 3 minutes. The refractive index of this polyvinyl alcohol-based adhesive was 1.490.
A liquid crystal display device was produced in the same manner as in Example 1 except that the polarizing plate 1 was changed to the polarizing plate 2.

Example 3
A polarizer protective film 3 is attached to one side of a polarizer composed of PVA and iodine so that the transmission axis of the polarizer and the phase advance axis of the film are parallel to each other, and a TAC film (Fuji Film Co., Ltd.) on the opposite side. Manufactured, with a thickness of 80 μm), and polarizing plate 3 was prepared. The polarizer, the polarizer protective film, and the TAC film were bonded together via an aqueous solution (polyvinyl alcohol-based adhesive) composed of 4 parts of polyvinyl alcohol, 1 part of melamine, and 95 parts of water, and dried at 60 ° C. for 3 minutes. The refractive index of this polyvinyl alcohol-based adhesive was 1.490.
A liquid crystal display device was produced in the same manner as in Example 1 except that the polarizing plate 1 was changed to the polarizing plate 3.

Example 4
A polarizer protective film 3 is attached to one side of a polarizer composed of PVA and iodine so that the transmission axis of the polarizer and the phase advance axis of the film are parallel to each other, and a TAC film (Fuji Film Co., Ltd.) on the opposite side. Manufactured, with a thickness of 80 μm), and polarizing plate 3 was prepared. The polarizer, the polarizer protective film, and the TAC film were bonded together via an aqueous solution (polyvinyl alcohol-based adhesive) composed of 4 parts of polyvinyl alcohol, 1 part of melamine, and 95 parts of water, and dried at 60 ° C. for 3 minutes. The refractive index of this polyvinyl alcohol-based adhesive was 1.490.
The polarizing plate on the light source side of BRAVIA KDL-40W920A (liquid crystal display device having a light source that emits excitation light and a backlight light source including quantum dots) manufactured by SONY is used, and the polyester film is opposite to the liquid crystal (distal) Thus, a liquid crystal display device was prepared by replacing the polarizing plate 3 with the above. In addition, it replaced so that the direction of the transmission axis of the polarizing plate 3 might become the same as the direction of the transmission axis of the polarizing plate before replacement.

(Example 5)
A polarizer protective film 3 is attached to one side of a polarizer composed of PVA and iodine so that the transmission axis of the polarizer and the phase advance axis of the film are parallel to each other, and a TAC film (Fuji Film Co., Ltd.) on the opposite side. Manufactured, with a thickness of 80 μm), and polarizing plate 3 was prepared. The polarizer, the polarizer protective film, and the TAC film were bonded together via an aqueous solution (polyvinyl alcohol-based adhesive) composed of 4 parts of polyvinyl alcohol, 1 part of melamine, and 95 parts of water, and dried at 60 ° C. for 3 minutes. The refractive index of this polyvinyl alcohol-based adhesive was 1.490.
The polarizing film on the viewing side and the light source side of BRAVIA KDL-40W920A (a liquid crystal display device having a light source that emits excitation light and a backlight light source including quantum dots) manufactured by SONY is used. The liquid crystal display device was prepared by replacing the polarizing plate 3 so that In addition, it replaced so that the direction of the transmission axis of the polarizing plate 3 might become the same as the direction of the transmission axis of the polarizing plate before replacement.

(Example 6)
A polarizer protective film 4 is attached to one side of a polarizer composed of PVA and iodine so that the transmission axis of the polarizer and the phase advance axis of the film are parallel to each other, and a TAC film (FUJIFILM Corporation) Manufactured, with a thickness of 80 μm), and polarizing plate 4 was created. The polarizer, the polarizer protective film, and the TAC film were bonded together via an aqueous solution (polyvinyl alcohol-based adhesive) composed of 4 parts of polyvinyl alcohol, 1 part of melamine, and 95 parts of water, and dried at 60 ° C. for 3 minutes. The refractive index of this polyvinyl alcohol-based adhesive was 1.490.
A liquid crystal display device was produced in the same manner as in Example 1 except that the polarizing plate 1 was changed to the polarizing plate 4.

(Example 7)
A polarizer protective film 5 is attached to one side of a polarizer made of PVA and iodine so that the transmission axis of the polarizer and the fast axis of the film are parallel to each other, and a TAC film (Fuji Film Co., Ltd.) on the opposite side. Manufactured, with a thickness of 80 μm) to make a polarizing plate 5. The polarizer, the polarizer protective film, and the TAC film were bonded together via an aqueous solution (polyvinyl alcohol-based adhesive) composed of 4 parts of polyvinyl alcohol, 1 part of melamine, and 95 parts of water, and dried at 60 ° C. for 3 minutes. The refractive index of this polyvinyl alcohol-based adhesive was 1.490.
A liquid crystal display device was produced in the same manner as in Example 1 except that the polarizing plate 1 was changed to the polarizing plate 5.

(Example 8)
A polarizer protective film 6 is attached to one side of a polarizer made of PVA and iodine so that the transmission axis of the polarizer and the phase advance axis of the film are parallel to each other, and a TAC film (Fuji Film Co., Ltd.) on the opposite side. Manufactured, with a thickness of 80 μm) to make a polarizing plate 6. The polarizer, the polarizer protective film, and the TAC film were bonded together via an aqueous solution (polyvinyl alcohol-based adhesive) composed of 4 parts of polyvinyl alcohol, 1 part of melamine, and 95 parts of water, and dried at 60 ° C. for 3 minutes. The refractive index of this polyvinyl alcohol-based adhesive was 1.490.
A liquid crystal display device was produced in the same manner as in Example 1 except that the polarizing plate 1 was changed to the polarizing plate 6.

(Comparative 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, with a thickness of 80 μm), and a polarizing plate 7 was prepared. The polarizer, the polarizer protective film, and the TAC film were bonded together via an aqueous solution (polyvinyl alcohol-based adhesive) composed of 4 parts of polyvinyl alcohol, 1 part of melamine, and 95 parts of water, and dried at 60 ° C. for 3 minutes. The refractive index of this polyvinyl alcohol-based adhesive was 1.490.
The polarizing plate on the viewing side of BRAVIA KDL-40W920A (a liquid crystal display device having a light source that emits excitation light and a backlight light source including quantum dots) manufactured by Sony, the polyester film is opposite to the liquid crystal (distal) Thus, a liquid crystal display device was prepared by replacing the polarizing plate 7. In addition, it replaced so that the direction of the transmission axis of the polarizing plate 7 might become the same as the direction of the transmission axis of the polarizing plate before replacement.

(Comparative Example 2)
A polarizer protective film 2 is attached to one side of a polarizer made 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, with a thickness of 80 μm), and polarizing plate 8 was created. The polarizer, the polarizer protective film, and the TAC film were bonded together via an aqueous solution (polyvinyl alcohol-based adhesive) composed of 4 parts of polyvinyl alcohol, 1 part of melamine, and 95 parts of water, and dried at 60 ° C. for 3 minutes. The refractive index of this polyvinyl alcohol-based adhesive was 1.490.
A liquid crystal display device was produced in the same manner as in Comparative Example 1 except that the polarizing plate 7 was changed to the polarizing plate 8.

(Comparative Example 3)
A polarizer protective film 3 is attached to one side of a polarizer made 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, with a thickness of 80 μm) to make a polarizing plate 9. The polarizer, the polarizer protective film, and the TAC film were bonded together via an aqueous solution (polyvinyl alcohol-based adhesive) composed of 4 parts of polyvinyl alcohol, 1 part of melamine, and 95 parts of water, and dried at 60 ° C. for 3 minutes. The refractive index of this polyvinyl alcohol-based adhesive was 1.490.
A liquid crystal display device was produced in the same manner as in Comparative Example 1 except that the polarizing plate 7 was changed to the polarizing plate 9.

(Comparative Example 4)
A polarizer protective film 3 is attached to one side of a polarizer made 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, with a thickness of 80 μm) to make a polarizing plate 9. The polarizer, the polarizer protective film, and the TAC film were bonded together via an aqueous solution (polyvinyl alcohol-based adhesive) composed of 4 parts of polyvinyl alcohol, 1 part of melamine, and 95 parts of water, and dried at 60 ° C. for 3 minutes. The refractive index of this polyvinyl alcohol-based adhesive was 1.490.
The polarizing plate on the light source side of BRAVIA KDL-40W920A (liquid crystal display device having a light source that emits excitation light and a backlight light source including quantum dots) manufactured by SONY is used, and the polyester film is opposite to the liquid crystal (distal) Thus, a liquid crystal display device was prepared by replacing the polarizing plate 9. In addition, it replaced so that the direction of the transmission axis of the polarizing plate 9 might become the same as the direction of the transmission axis of the polarizing plate before replacement.

(Comparative Example 5)
A polarizer protective film 3 is attached to one side of a polarizer made 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, with a thickness of 80 μm) to make a polarizing plate 9. The polarizer, the polarizer protective film, and the TAC film were bonded together via an aqueous solution (polyvinyl alcohol-based adhesive) composed of 4 parts of polyvinyl alcohol, 1 part of melamine, and 95 parts of water, and dried at 60 ° C. for 3 minutes. The refractive index of this polyvinyl alcohol-based adhesive was 1.490.
The polarizing film on the viewing side and the light source side of BRAVIA KDL-40W920A (a liquid crystal display device having a light source that emits excitation light and a backlight light source including quantum dots) manufactured by SONY is used. The liquid crystal display device was prepared by replacing the polarizing plate 9 so that In addition, it replaced so that the direction of the transmission axis of the polarizing plate 9 might become the same as the direction of the transmission axis of the polarizing plate before replacement.

(Comparative Example 6)
A polarizer protective film 4 is attached to one side of a polarizer made 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 μm) to make a polarizing plate 10. The polarizer, the polarizer protective film, and the TAC film were bonded together via an aqueous solution (polyvinyl alcohol-based adhesive) composed of 4 parts of polyvinyl alcohol, 1 part of melamine, and 95 parts of water, and dried at 60 ° C. for 3 minutes. The refractive index of this polyvinyl alcohol-based adhesive was 1.490.
A liquid crystal display device was produced in the same manner as in Comparative Example 1 except that the polarizing plate 7 was changed to the polarizing plate 10.

(Comparative Example 7)
A polarizer protective film 7 is attached to one side of a polarizer made of PVA and iodine so that the transmission axis of the polarizer and the phase advance axis of the film are parallel to each other, and a TAC film (Fuji Film Co., Ltd.) on the opposite side. Manufactured and having a thickness of 80 μm), a polarizing plate 11 was prepared. The polarizer, the polarizer protective film, and the TAC film were bonded together via an aqueous solution (polyvinyl alcohol-based adhesive) composed of 4 parts of polyvinyl alcohol, 1 part of melamine, and 95 parts of water, and dried at 60 ° C. for 3 minutes. The refractive index of this polyvinyl alcohol-based adhesive was 1.490.
A liquid crystal display device was produced in the same manner as in Comparative Example 1 except that the polarizing plate 7 was changed to the polarizing plate 11.

(Comparative Example 8)
A polarizer protective film 8 is attached to one side of a polarizer made of PVA and iodine so that the transmission axis of the polarizer and the fast axis of the film are parallel to each other, and a TAC film (Fuji Film Co., Ltd.) on the opposite side. Manufactured and having a thickness of 80 μm), a polarizing plate 12 was prepared. The polarizer, the polarizer protective film, and the TAC film were bonded together via an aqueous solution (polyvinyl alcohol-based adhesive) composed of 4 parts of polyvinyl alcohol, 1 part of melamine, and 95 parts of water, and dried at 60 ° C. for 3 minutes. The refractive index of this polyvinyl alcohol-based adhesive was 1.490.
A liquid crystal display device was produced in the same manner as in Comparative Example 1 except that the polarizing plate 7 was changed to the polarizing plate 12.

  Table 1 below shows the results of measurement of rainbow spot observation for the liquid crystal display devices obtained in each example.

  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 viewing angle, and the industrial applicability is extremely high. .

Claims (3)

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 less than 495 nm, 495 nm to less than 600 nm, and 600 nm to 750 nm, respectively, and the half width of each peak is 5 nm or more,
At least one polarizing plate of the two polarizing plates is obtained by laminating a polyester film via an adhesive layer on at least one surface of a polarizer,
The difference between the refractive index of the adhesive layer and the refractive index of the polyester film in a direction parallel to the transmission axis of the polarizer is 0.13 or less.
Liquid crystal display device. The liquid crystal display device according to claim 1, wherein the backlight source is a backlight source including a light source that emits excitation light and quantum dots. The liquid crystal display device according to claim 1, wherein the polyester film has a retardation of 1500 to 30000 nm.