KR102353531B1 - Liquid crystal display and polarizer - Google Patents

Abstract

A liquid crystal display device of the present invention includes a backlight light source, two polarizing plates, and a liquid crystal cell disposed between the two polarizing plates, wherein the backlight light source has each 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 780 nm or less. A white light emitting diode having a peak top of the emission spectrum in each wavelength region, and having an emission spectrum in which a peak with the highest peak intensity in a wavelength region of 600 nm or more and 780 nm or less has an emission spectrum of less than 5 nm, at least one of the polarizing plates Silver, a polyester film is laminated on at least one surface of the polarizer, the polyester film has a retardation of 1500 to 30000 nm, and an antireflection layer and / or a low reflection layer is laminated on at least one surface of the polyester film have.

Description

Liquid crystal display and polarizer

The present invention relates to a liquid crystal display device and a polarizing plate. In detail, it is related with the liquid crystal display device and polarizing plate by which generation|occurrence|production of the color unevenness of a rainbow image was reduced.

A polarizing plate used in a liquid crystal display (LCD) has a configuration in which a polarizer obtained by dyeing iodine in polyvinyl alcohol (PVA) or the like is usually sandwiched by two polarizer protective films, and a triacetyl cellulose (TAC) film is usually used as a polarizer protective film. is being used In recent years, with thinning of LCD, thinning of a polarizing plate is calculated|required. However, for this reason, when the thickness of the TAC film used as a protective film is made thin, sufficient mechanical strength cannot be obtained and the problem that moisture permeability deteriorates will arise. Moreover, the TAC film is very expensive, and although a polyester film has been proposed as an inexpensive alternative material (patent documents 1-3), there existed a problem of rainbow-like color unevenness.

When the oriented polyester film which has birefringence is arrange|positioned on one side of a polarizer, a polarization state changes when linearly polarized light radiate|emitted from a backlight unit or a polarizer passes through a polyester film. The transmitted light exhibits an interference color unique to retardation, which is the product of the thickness and the birefringence of the oriented polyester film. Therefore, when a discontinuous emission spectrum such as a cold cathode tube or a hot cathode tube is used as a light source, transmitted light intensity differs depending on the wavelength, resulting in rainbow-like color irregularities (refer to the 15th Micro-Optical Conference Notice, Paragraphs 30 to 31) ).

As a means to solve the above problem, using 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 constant retardation as a polarizer protective film It has been proposed (Patent Document 4). A white light emitting diode has a continuous and broad emission spectrum in the visible region. Therefore, when paying attention to the envelope shape of the interference color spectrum by the transmitted light passing through the birefringent, by controlling the retardation of the oriented polyester film, a spectrum similar to the emission spectrum of the light source is obtained, and it is possible to suppress rainbow spots is being proposed

Furthermore, by making the orientation direction of an orientation polyester film and the polarization direction of a polarizing plate orthogonal or parallel to it, even if linearly polarized light emitted from a polarizer passes through an orientation polyester film, it will pass while maintaining a polarization state. In addition, by controlling the birefringence of the oriented polyester film to increase the uniaxial orientation, light incident from the oblique direction also passes while maintaining the polarization state. When the oriented polyester film is viewed from an angle, shift in the orientation principal axis direction is generated compared with when viewed from directly above. For this reason, it is thought that the shift|offset|difference between the direction of linearly polarized light and the orientation main axis direction becomes small, and it becomes difficult to generate|occur|produce the change of a polarization state. As described above, by controlling the emission spectrum of the light source, the orientation state of the birefringent, and the orientation principal axis direction, it was thought that the change in the polarization state was suppressed, the rainbow-like color unevenness did not occur, and the visibility was remarkably improved.

Japanese Patent Laid-Open No. 2002-116320 Japanese Patent Laid-Open No. 2004-219620 Japanese Patent Laid-Open No. 2004-205773 WO2011/162198

Due to the rising demand for color gamut expansion of liquid crystal display devices in recent years, each wavelength region of the blue region (400 nm or more and less than 495 nm), the green region (495 nm or more and less than 600 nm) and the red region (600 nm or more and 780 nm or less) has a light emission spectrum _{A white light emitting diode (for example, a blue light emitting diode and at least K 2} SiF ₆ as a phosphor and a blue light emitting diode) having a peak top and a relatively narrow (less than 5 nm) emission spectrum of the peak in the red region (600 nm or more and 780 nm or less) A liquid crystal display device using a backlight light source including: a white light emitting diode having a fluoride phosphor such as ^{Mn 4 + , etc.) is being developed.}

When a liquid crystal display device is industrially produced using a polarizing plate using a polyester film as a polarizer protective film, the direction of the transmission axis of a polarizer and the fast axis of a polyester film is arrange|positioned so that it may become mutually perpendicular|vertical normally. This is because the polyvinyl alcohol film, which is a polarizer, is manufactured by longitudinal uniaxial stretching, and the polyester film, which is the protective film, is manufactured by longitudinal stretching and then transverse stretching. This is because, when a polarizing plate is manufactured by bonding these elongated objects, the fast axis of the polyester film and the transmission axis of the polarizer are usually perpendicular. In this case, an oriented polyester film having a specific retardation is used as the polyester film, and as a backlight light source, for example, a white LED comprising a light emitting element in which a blue light emitting diode and a yttrium aluminum garnet system yellow phosphor are combined. By using a representative light source having a continuous and broad emission spectrum, the color unevenness of the rainbow is significantly improved, but the emission spectrum of the peak in the red region (600 nm or more and 780 nm or less) is relatively narrow (less than 5 nm). When a backlight light source including a white light emitting diode having

That is, the subject of the present invention has a peak top of the emission spectrum in each wavelength region of the blue region (400 nm or more and less than 495 nm), the green region (495 nm or more and less than 600 nm), and the red region (600 nm or more and 780 nm or less), respectively, in the red region In a liquid crystal display device having a backlight light source including a white light emitting diode having a relatively narrow (less than 5 nm) emission spectrum with a peak at half maximum width (600 nm or more and 780 nm or less), even when a polyester film is used as a polarizer protective film , to provide a liquid crystal display device and a polarizing plate in which rainbow spots are suppressed.

Representative of the present invention is as follows.

Section 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 light source has a peak top of the emission spectrum in each wavelength region 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 780 nm or less, and the peak intensity of the highest peak in the wavelength region of 600 nm or more and 780 nm or less is half the peak. a white light emitting diode having an emission spectrum less than 5 nm in width;

At least one of the polarizing plates is one in which a polyester film is laminated on at least one surface of the polarizer,

The polyester film has a retardation of 1500 to 30000 nm,

At least one surface of the polyester film is laminated with an anti-reflection layer and/or a low-reflection layer,

liquid crystal display.

Section 2.

The emission spectrum of the backlight light source is,

The half-width of the peak with the highest peak intensity in the wavelength region of 400 nm or more and less than 495 nm is 5 nm or more,

The half-width of the peak with the highest peak intensity in the wavelength region of 495 nm or more and less than 600 nm is 5 nm or more,

The liquid crystal display device of Claim 1.

Section 3.

The liquid crystal display device according to item 1 or 2, wherein the surface reflectance of the surface of the antireflection layer at a wavelength of 550 nm is 2.0% or less.

Section 4.

It is a polarizing plate in which a polyester film is laminated on at least one side of the polarizer,

The polyester film has a retardation of 1500 to 30000 nm, and an antireflection layer and/or a low reflection layer are laminated on at least one surface of the polyester film,

400 nm or more and less than 495 nm, 495 nm or more and less than 600 nm, and each wavelength region of 600 nm or more and 780 nm or less has a peak top of the emission spectrum, respectively, and the half-width of the peak with the highest peak intensity in the wavelength region of 600 nm or more and 780 nm or less is less than 5 nm A polarizing plate for a liquid crystal display having a backlight light source including a white light emitting diode having an emission spectrum.

Section 5.

The polarizing plate according to item 4, wherein the surface reflectance of the antireflection layer surface at a wavelength of 550 nm is 2.0% or less.

The liquid crystal display device and polarizing plate of this invention can ensure favorable visibility by which generation|occurrence|production of the color unevenness of a rainbow shape was suppressed significantly from any observation angle.

In general, a liquid crystal display device is constituted of a rear face module, a liquid crystal cell, and a front face module in the order from the side opposite to 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 disposed on the side opposite to the backlight light source in the rear module, and is disposed on the image display side (viewer side) in the front module.

The liquid crystal display device of this invention makes a backlight light source and the liquid crystal cell arrange|positioned between two polarizing plates into structural members at least.

In addition, a liquid crystal display device may have suitably other structures other than a backlight light source, a polarizing plate, and a liquid crystal cell, for example, a color filter, a lens film, a diffusion sheet, an antireflection film, etc. suitably. You may provide a brightness improvement film between a light source side polarizing plate and a backlight light source. As a brightness improving film, the reflection type polarizing plate which transmits one linearly polarized light and reflects linearly polarized light orthogonal to it is mentioned, for example. As a reflective polarizing plate, the brightness improving film of the DBEF (trademark) (Dual Brightness Enhancement Film) series by Sumitomo 3M Corporation is used suitably, for example. In addition, the reflective polarizing plate is usually arranged so that the absorption axis of the reflective polarizing plate and the absorption axis of the light source-side polarizing plate are parallel to each other.

At least one of the two polarizing plates disposed in the liquid crystal display device has a polyester film laminated on at least one surface of the polarizers in which iodine is dyed with polyvinyl alcohol (PVA) or the like. In this invention, from a viewpoint of suppressing rainbow-like color unevenness, a polyester film has specific retardation, and an antireflection layer and/or a low reflection layer are laminated|stacked on at least one surface of a polyester film. An antireflection layer and/or a low reflection layer may be provided in the surface on the opposite side to the surface which laminates|stacks the polarizer of a polyester film, and may be provided in the surface where the polarizer of a polyester film is laminated|stacked, and both may be sufficient as them. Preferably, it is preferable to form an antireflection layer and/or a low reflection layer on the surface on the opposite side to the surface on which the polarizer of a polyester film is laminated|stacked. When providing an antireflection layer and/or a low reflection layer on the surface on which a polarizer of a polyester film is laminated|stacked, it is preferable that an antireflection layer and/or a low reflection layer are provided between a polyester film and a polarizer. In addition, between the antireflection layer and/or the low reflection layer and the polyester film, another layer (for example, an easily bonding layer, a hard-coat layer, a glare-proof layer, an antistatic layer, an antifouling layer, etc.) may exist. It is preferable that the refractive index of the said polyester film of the direction parallel to the transmission axis of a polarizer from a viewpoint of suppressing more rainbow-like color unevenness is 1.53 - 1.62. On the other side of the polarizer, a film without birefringence such as a TAC film, an acrylic film, or a norbornene-based film is preferably laminated (a polarizing plate having a three-layer structure), but the film must be laminated on the other side of the polarizer It does not have to be (a polarizing plate with a two-layer structure). Moreover, when a polyester film is used as both sides protective film of a polarizer, it is preferable that the slow axes of both polyester films are mutually substantially parallel.

A polarizer can be used, selecting suitably arbitrary polarizers (polarizing film) used in the said technical field. Representative examples of the polarizer include those obtained by dyeing a polyvinyl alcohol film with a dichroic material such as iodine, but the present invention is not limited thereto, and polarizers known and developed in the future can be appropriately selected and used.

A commercial item can be used for a PVA film, For example, "Kuraray vinylon (made by Kurare Co., Ltd.)", "Toserobinyllon (made by Tocello Co., Ltd.)], "Nichigo vinylon (Nippon Kosei Chemical Co., Ltd.)" Note)]] can be used. Examples of the dichroic material include iodine, diazo compounds, and polymethine dyes.

A polarizer can be obtained by arbitrary methods, for example, uniaxially stretching what dyed the PVA film with a dichroic material in boric-acid aqueous solution, It can obtain by washing|cleaning and drying, maintaining an extending|stretching state. Although the draw ratio of uniaxial stretching is about 4 to 8 times normally, it is not restrict|limited in particular. Other manufacturing conditions, etc. can be set suitably according to a well-known method.

As the configuration of the backlight, it may be an edge light system or a direct system in which a light guide plate or a reflecting plate is used as a constituent member. A backlight light source comprising a white light emitting diode having a peak top of the emission spectrum in each wavelength region of 780 nm or less, and an emission spectrum having the highest peak intensity peak in the wavelength region of 600 nm or more and 780 nm or less and an emission spectrum of less than 5 nm This is preferable.

It is known that the respective peak wavelengths of blue, green, and red defined in the CIE chromaticity diagram are 435.8 nm (blue), 546.1 nm (green) and 700 nm (red), respectively. Each wavelength region 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 less than 780 nm corresponds to a blue region, a green region, and a red region, respectively.

The upper limit of the half-width of the peak having the highest peak intensity in the wavelength region of 600 nm or more and 780 nm or less is preferably less than 5 nm, more preferably less than 4 nm, still more preferably less than 3.5 nm. The lower limit is preferably 1 nm or more, more preferably 1.5 nm or more. Since the color gamut of a liquid crystal display device becomes it that the half-width of a peak is less than 5 nm, it is preferable. Moreover, there exists a possibility that luminous efficiency may worsen that the half-width of a peak is less than 1 nm. The shape of the emission spectrum is designed from the balance between the required color gamut and the luminous efficiency. In addition, here, the half width is the peak width (nm) at the intensity|strength of 1/2 of the peak intensity in the wavelength of a peak top.

Application of a backlight light source having an emission spectrum having the above-described characteristics to an LCD is a technology that is attracting attention due to a recent increase in demand for color gamut expansion. In an LED using a conventionally used white LED (for example, a light emitting element combining a blue light emitting diode and a yttrium/aluminum/garnet-based yellow phosphor) as a backlight light source, only about 20% of the spectrum that the human eye can recognize Color cannot be reproduced. On the other hand, it is said that 60% or more of colors can be reproduced when a backlight light source having an emission spectrum having the above characteristics is used.

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 range of 600 nm or more and 780 nm or less is more preferably 600 nm or more and 700 nm or less, and still more preferably 610 nm or more and 680 mn or less.

The peak half-width (half-width of the peak having the highest peak intensity in each wavelength region) at the peak top of each wavelength region of 400 nm or more and less than 495 nm and 495 nm or more and less than 600 nm of the emission spectrum is not particularly limited, but 400 nm or more and 495 nm It is preferable that the half-width of the peak having the highest peak intensity in a wavelength region of less than 5 nm is 5 nm or more, and it is preferable that the half-width of the peak having the highest peak intensity in the wavelength region of 495 nm or more and less than 600 nm is 5 nm or more. From the viewpoint of securing an appropriate color gamut, the upper limit of the peak half-width at the peak top of each wavelength region of 400 nm or more and less than 495 nm and 495 nm or more and less than 600 nm (the half-width of the peak having the highest peak intensity in each wavelength region) is , Preferably it is 140 nm or less, Preferably it is 120 nm or less, Preferably it is 100 nm or less, More preferably, it is 80 nm or less, More preferably, it is 60 nm or less, Even more preferably, it is 50 nm or less.

As a white light source which has the emission spectrum which has the above-mentioned characteristic, specifically, for example, the fluorescent substance type white light emitting diode which combined a blue light emitting diode and a fluorescent substance is mentioned. Examples of the red phosphor among the phosphors include a _{fluoride phosphor having a composition formula of K 2} SiF ₆ :Mn ⁴⁺ (also referred to as “KSF”), and others. The Mn ^{4 +} activated fluoride complex phosphor is a phosphor in which Mn ^{4 +} is an activator and a fluoride complex salt of an alkali metal, an amine or an alkaline earth metal is used as a matrix crystal. In the fluoride complex forming the parent crystal, the coordination center is that of a trivalent metal (B, Al, Ga, In, Y, Sc, lanthanoid), a tetravalent metal (Si, Ge, Sn, Ti, Zr, Re, Hf) and pentavalent metals (V, P, Nb, Ta), and the number of fluorine atoms coordinated around them is 5 to 7.

Suitable examples of the Mn ^{4 +} activated fluoride complex phosphor include A ₂ [MF ₆ ]:Mn (A is at least one selected from Li, Na, K, Rb, Cs, NH ₄ ; M is Ge, Si, Sn, Ti , at least one selected from Zr), E[MF ₆ ]:Mn (E is at least one selected from Mg, Ca, Sr, Ba, Zn; M is selected from Ge, Si, Sn, Ti, and Zr one or _{more), Ba 0 .65, Zr 0} .35 F 2.70: Mn, A 3 [ZrF 7]: Mn (A is Li, Na, K, Rb, Cs, at least one member selected from NH _4), A ₂ [MF ₅ ]:Mn (A is at least one selected from Li, Na, K, Rb, Cs, NH ₄ ; M is at least one selected from Al, Ga, In), A ₃ [MF ₆ ]:Mn (A is at least one selected from Li, Na, K, Rb, Cs, NH ₄ ; M is at least one selected from Al, Ga, In), Zn ₂ [MF ₇ ]:Mn(M is Al, Ga, at least one selected from In), A[In ₂ F ₇ ]:Mn (A is at least one selected from Li, Na, K, Rb, Cs, NH ₄ ), and the like.

One of the preferred Mn ^{4 +} _{activated fluoride complex phosphors is A 2} MF ₆ :Mn (A is 1 selected from Li, Na, K, Rb, Cs, NH _{4 )} having a hexafluoro complex salt of an alkali metal as a parent crystal. at least one species; M is at least one selected from Ge, Si, Sn, Ti, and Zr). Among them, preferably, A is at least one selected from K (potassium) or Na (sodium), and M is Si (silicon) or Ti (titanium). Among them, it is preferable that A is K (the ratio of K to the total amount of A is 99 mol% or more) and M is Si in particular. It is preferable that Mn (manganese) is 100% of the activating element, but Ti, Zr, Ge, Sn, Al, Ga, B, In, Cr, Fe, Co, Ti, Zr, Ge, Sn, Al, Ga, B, In, Cr, Fe, Co, Ni, Cu, Nb, Mo, Ru, Ag, Zn, Mg, etc. may be contained. When M is Si, it is preferable that the ratio of Mn in the total of Si and Mn exists in the range of 0.5 mol% - 10 mol%. As another preferred Mn ^{4 +} activated fluoride complex phosphor, Formula A _{2+ x} M _y Mn _z F _n (A is Na and K; M is Si and Al; -1≤x≤1 Also 0.9≤y+z≤1.1 Also 0.001 ≤ z ≤ 0.4 and 5 ≤ n ≤ 7).

The backlight light source is preferably a blue light emitting diode and a white light emitting diode having at least a fluoride phosphor as a phosphor, particularly preferably a blue light emitting diode and a white light emitting diode having a fluoride phosphor _{of at least K 2} SiF ₆ :Mn ^{4 + as the phosphor.} to be. For example, commercial items, such as NSSW306FT which is a white LED by the Nichia Chemical Industry Co., Ltd. can be used.

In addition, as the green phosphor among the phosphors, for example, a sialon-based phosphor having a basic composition such as β-SiAlON:Eu, a silicate-based phosphor having a basic composition such as _{(Ba,Sr) 2} SiO _{4 :Eu, etc.} is exemplified

In addition, when a plurality of peaks exist in any wavelength region of a wavelength region of 400 nm or more and less than 495 nm, a wavelength region of 495 nm or more and less than 600 nm, or a wavelength region of 600 nm or more and less than 780 nm, it is considered as follows.

When a plurality of peaks are independent peaks, it is preferable that the half-width of the peak having the highest peak intensity is within the above range. Moreover, also about the other peak which has intensity|strength of 70% or more of the highest peak intensity, it is a more preferable aspect that a half-width becomes the said range similarly.

For one independent peak having a shape in which a plurality of peaks overlapped, the half-width is used when the half-width of the peak having the highest peak intensity among the plurality of peaks can be measured as it is. Here, an independent peak has an intensity|region which becomes 1/2 of a peak intensity on both the short-wavelength side and the long-wavelength side of a peak. That is, when a plurality of peaks overlap and each individual peak does not have a region having an intensity equal to 1/2 of the peak intensity on both sides thereof, the plurality of peaks are regarded as one peak as a whole. In the case of one peak having such a shape in which a plurality of peaks are overlapped, the width (nm) of the peak at half the intensity of the highest peak intensity among them is taken as the half width.

Moreover, let the peak with the highest peak intensity among several peaks be a peak top.

In addition, the peak having the highest peak intensity in each wavelength region of a wavelength region of 400 nm or more and less than 495 nm, a wavelength region of 495 nm or more and less than 600 nm, or a wavelength region of 600 nm or more and 780 nm or less is independent from the peaks of other wavelength regions. It is desirable to be in a relationship. 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 and the peak having the highest peak intensity in the region of 600 nm or more and 780 nm or less, the intensity is the highest in the wavelength region of 600 nm or more and 780 nm or less. It is preferable from the viewpoint of color vividness that a region which becomes 1/3 or less of the peak intensity of a peak having a high peak intensity exists.

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

As a result of intensive examination, the present inventors, like the above-described backlight light source, each wavelength region of the blue region (400 nm or more and less than 495 nm), the green region (495 nm or more and less than 600 nm) and the red region (600 nm or more and 780 nm or less) of the emission spectrum, respectively. In the liquid crystal display device having a backlight light source including a white light emitting diode having a peak top and having a peak in the red region (600 nm or more and 780 nm or less) having a relatively narrow half width of less than 5 nm, an antireflection layer and/or as a polarizer protective film It has a low reflection layer, and when the polyester film which has specific retardation was used, it discovered that the liquid crystal display device and polarizing plate by which rainbow_pattern|erythema were suppressed were provided. As a mechanism by which generation|occurrence|production of the color unevenness of a rainbow shape is suppressed by the said aspect, it considers as follows.

When an orientation polyester film is arrange|positioned on one side of a polarizer, when linearly polarized light radiate|emitted from a backlight unit or a polarizer passes a polyester film, a polarization state changes. As one of the factors to which a polarization state changes, the possibility that the refractive index difference of the interface of an air layer and an oriented polyester film or the refractive index difference of the interface of a polarizer and an oriented polyester film is having influence is considered. When the linearly polarized light which injected into the orientation polyester film passes through each interface, a part of light is reflected by the refractive index difference between interfaces. At this time, the polarization state of the emitted light and the reflected light also changes, and this is considered to be one of the factors which generate|occur|produce the color unevenness of a rainbow shape. For this reason, by providing an antireflection layer or a low reflection layer to the surface of an orientation polyester film, and reducing surface reflection, reflection of the interface of an air layer and an orientation polyester film is suppressed, and it is thought that rainbow-like color unevenness is suppressed.

As described above, in the present invention, each wavelength region of the blue region (400 nm or more and less than 495 nm), the green region (495 nm or more and less than 600 nm) and the red region (600 nm or more and 780 nm or less) has a peak top of the emission spectrum, respectively, in the red region ( In a liquid crystal display device having a backlight light source including a white light emitting diode having a relatively narrow half-width of the peak at 600 nm or more and 780 nm or less) of less than 5 nm, even if a polarizing plate using a polyester film is used as a polarizer protective film, rainbow-like colors It becomes possible to have favorable visibility without generating a nonuniformity.

It is preferable that the polarizer protective film containing a polyester film is laminated|stacked on at least one surface among polarizers on a polarizing plate. It is preferable that the polyester film used for a polarizer protective film has retardation of 1500-30000 nm. When retardation exists in the said range, there exists a tendency for a rainbow_pattern|erythema to become easy to reduce more, and it is preferable. A preferable lower limit of retardation is 3000 nm, a next preferable lower limit is 3500 nm, a more preferable lower limit is 4000 nm, a more preferable lower limit is 6000 nm, and a still more preferable lower limit is 8000 nm. A preferable upper limit is 30000 nm, and in the polyester film which has retardation more than this, thickness becomes large considerably, and there exists a tendency for the handleability as an industrial material to fall. In this document, retardation means in-plane retardation, except when otherwise indicated.

In addition, retardation can also measure and obtain|require the refractive index and thickness of a biaxial direction, and can also be calculated|required using the commercially available automatic birefringence measuring apparatus called KOBRA-21ADH (Oji Keisoku Kikin Co., Ltd.). In addition, the refractive index can be calculated|required with Abbe's refractometer (measurement wavelength 589 nm).

Ratio (Re/Rth) of retardation (Re: in-plane retardation) of a polyester film and retardation (Rth) of thickness direction becomes like this. Preferably it is 0.2 or more, More preferably, it is 0.5 or more, More preferably, 0.6 More than that. The larger the ratio (Re/Rth) of the retardation and the thickness direction retardation, the more isotropic the action of birefringence, and the more difficult it is for the occurrence of rainbow-like color unevenness due to the observation angle to occur. In a perfectly uniaxial (uniaxially symmetric) film, the ratio (Re/Rth) of the retardation to the thickness direction retardation is 2.0, so the upper limit of the ratio (Re/Rth) of the retardation to the thickness direction retardation is 2.0 This is preferable. In addition, the thickness direction retardation means the average of the retardation obtained by multiplying the film thickness d by two birefringence (DELTA)Nxz, (DELTA)Nyz, respectively, when a film is seen from the thickness direction cross section.

It is preferable that the NZ coefficient of a polyester film is 2.5 or less from a viewpoint of suppressing more rainbow-like color unevenness, More preferably, it is 2.0 or less, More preferably, it is 1.8 or less, More preferably, it is 1.6 or less. And in a perfect uniaxial (uniaxially symmetrical) film, since NZ coefficient becomes 1.0, the lower limit of NZ coefficient is 1.0. However, it is necessary to note that the mechanical strength in the direction orthogonal to the orientation direction tends to decrease remarkably as the film approaches a perfect uniaxial (uniaxially symmetric) film.

The NZ coefficient is expressed as |Ny-Nz|/|Ny-Nx|, where Ny is the refractive index in the slow axis direction, Nx is the refractive index in the direction orthogonal to the slow axis (the refractive index in the fast axis direction), and Nz is the thickness It indicates the refractive index of the direction. The orientation axis of the film was determined using a molecular orientation meter (manufactured by Oji Keisoku Co., Ltd., MOA-6004 type molecular orientation meter), and the biaxial refractive index (Ny, Nx, except Ny) in the direction of the orientation axis and the direction orthogonal thereto. >Nx) and the refractive index (Nz) in the thickness direction are determined by Abbe's refractometer (manufactured by Atago, NAR-4T, measurement wavelength 589 nm). The NZ coefficient can be calculated|required by substituting the value calculated|required in this way into |Ny-Nz|/|Ny-Nx|.

Moreover, as for the value of Ny-Nx of a polyester film from a viewpoint of suppressing more rainbow-like color unevenness, 0.05 or more are preferable, More preferably, 0.07 or more, More preferably, 0.08 or more, More preferably, 0.09 or more. or more, particularly preferably 0.1 or more. Although the upper limit is not particularly set, in the case of a polyethylene terephthalate-based film, the upper limit is preferably about 1.5.

As a more preferable aspect in this invention, it is preferable to make the refractive index of the polyester film of the direction parallel to the transmission axis direction of the polarizer which comprises a polarizing plate into the range of 1.53 or more and 1.62 or less. Thereby, it becomes possible to suppress the reflection in the interface of a polarizer and a polyester film, and to suppress more the color unevenness of a rainbow shape. When refractive index exceeds 1.62 and it observes from an oblique direction, rainbow-like color nonuniformity may generate|occur|produce. The polyester film refractive index of the direction parallel to the transmission axis direction of a polarizer becomes like this. Preferably it is 1.61 or less, More preferably, it is 1.60 or less, More preferably, it is 1.59 or less, More preferably, it is 1.58 or less.

On the other hand, the lower limit of the refractive index of the polyester film in a direction parallel to the transmission axis direction of the polarizer is 1.53. When the said refractive index will be less than 1.53, crystallization of a polyester film will become inadequate, and it is unpreferable at the point which characteristics obtained by extending|stretching, such as dimensional stability, mechanical strength, and chemical-resistance, become inadequate. The said refractive index becomes like this. Preferably it is 1.56 or more, More preferably, it is 1.57 or more. Any range combining each upper limit and each lower limit of the said refractive index mentioned above is assumed.

In order to set the refractive index of the polyester film in a direction parallel to the direction of the transmission axis of the polarizer in the range of 1.53 or more and 1.62 or less, the transmission axis of the polarizer and the fast axis (vertical direction to the slow axis) of the polyester film of the polarizing plate are approximately Parallel is preferred. The polyester film can adjust the refractive index of the fast axis direction which is a direction perpendicular to a slow axis as low as about 1.53 to 1.62 by the extending|stretching process in the film forming process mentioned later. By making the fast axis direction of a polyester film and the transmission axis direction of a polarizer substantially parallel, the polyester film refractive index of the direction parallel to the transmission axis direction of a polarizer can be set to 1.53 - 1.62. Here, substantially parallel means that the angle between the transmission axis of the polarizer and the fast axis of the polarizer protective film (polyester film) is -15° to 15°, preferably -10° to 10°, more preferably -5 ° to 5°, more preferably -3° to 3°, still more preferably -2° to 2°, still more preferably -1° to 1°. In a preferred embodiment, substantially parallel is substantially parallel. Substantially parallel here means that the transmission axis of a polarizer and the fast axis of a polyester film are parallel to the extent to which the shift|offset|difference which arises inevitably when bonding a polarizer and a protective film is permissible. The direction of the slow axis can be measured and calculated|required with the molecular orientation meter (For example, the Oji Scientific Instruments make, MOA-6004 type molecular orientation meter).

That is, the refractive index in the fast axis direction of the polyester film is preferably 1.53 or more and 1.62 or less, and by laminating so that the transmission axis of the polarizer and the fast axis of the polyester film are substantially parallel to each other, the polyester in a direction parallel to the transmission axis of the polarizer The refractive index of a film can be 1.53 or more and 1.62 or less.

The polarizer protective film containing the polyester film can be used for both polarizing plates on the incident light side (light source side) and outgoing light side (viewer side), but at least the protective film of the polarizing plate on the outgoing light side (viewer side) desirable.

Regarding the polarizing plate disposed on the outgoing light side, the polarizer protective film including the polyester film may be disposed on the liquid crystal cell side with the polarizer as a starting point, disposed on the outgoing light side, or on both sides, but at least on the outgoing light side It is preferable to arrange.

Also in the polarizing plate disposed on the incident light side, the polarizer protective film including the polyester film may be disposed on the incident light side with the polarizer as a starting point, or may be disposed on the liquid crystal cell side or on both sides, but at least on the incident light side It is a preferable form to be arranged in the . In addition, the polarizing plate arrange|positioned on the incident light side may not use the polarizer protective film containing a polyester film, but what used retardation low polarizer protective films, such as a triacetyl cellulose film.

Although a polyethylene terephthalate and a polyethylene naphthalate can be used for polyester used for a polyester film, it does not matter even if another copolymerization component is included. While these resins are excellent in transparency, they are excellent also in thermal and mechanical properties, and retardation can be controlled easily by extending|stretching process. In particular, polyethylene terephthalate has a large intrinsic birefringence, and by stretching the film, the refractive index in the fast axis (perpendicular to the slow axis direction) can be suppressed to be low, and large retardation is obtained relatively easily even when the film is thin. In this case, it is the most suitable material.

Moreover, for the purpose of suppressing deterioration of optically functional dyes, such as an iodine dye, it is preferable that the light transmittance of wavelength 380nm of a polyester film is 20 % or less. The light transmittance of 380 nm is more preferably 15% or less, still more preferably 10% or less, and particularly preferably 5% or less. If the said light transmittance is 20 % or less, the deterioration by the ultraviolet-ray of an optically functional dye can be suppressed. In addition, the transmittance|permeability is what measured by the method perpendicular|vertical with respect to the plane of a film, and can measure using the spectrophotometer (For example, Hitachi U-3500 type|mold).

In order to make the transmittance|permeability of wavelength 380nm of a polyester film 20 % or less, it is preferable to adjust appropriately the kind, density|concentration, and the thickness of a film of a ultraviolet absorber. The ultraviolet absorber used in the present invention is a known material. Although an organic type ultraviolet absorber and an inorganic type ultraviolet absorber are mentioned as a ultraviolet absorber, From a transparency viewpoint, an organic type ultraviolet absorber is preferable. Although a benzotriazole type, a benzophenone type, a cyclic iminoester type, etc. are mentioned as an organic type ultraviolet absorber, As long as it is the range of the absorbance prescribed|regulated by this invention, it will not specifically limit. However, from a durable viewpoint, a benzotriazole type and a cyclic iminoester type are especially preferable. When two or more types of ultraviolet absorbers are used together, since the ultraviolet-ray of each wavelength can be absorbed simultaneously, the ultraviolet-ray absorption effect can be improved more.

As a benzophenone-type ultraviolet absorber, a benzotriazole-type ultraviolet absorber, and an acrylonitrile-type ultraviolet absorber, it is 2-[2'-hydroxy-5'-(methacryloyloxymethyl)phenyl]-2H-benzotriazole, for example. , 2-[2'-hydroxy-5'-(methacryloyloxyethyl)phenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-(methacryloyloxypropyl) Phenyl]-2H-benzotriazole, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 2,4-di- tert-Butyl-6-(5-chlorobenzotriazol-2-yl)phenol, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2 -(5-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. As a cyclic iminoester type ultraviolet absorber, for example, 2,2'-(1,4-phenylene)bis (4H-3,1-benzoxazin-4-one), 2-methyl-3,1-benzooxazin-4-one, 2-butyl-3,1-benzooxazin-4-one, 2- phenyl-3,1-benzooxazin-4-one, etc. However, it is 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 impair the effect of this invention other than a ultraviolet absorber. Examples of the additive include inorganic particles, heat-resistant polymer particles, alkali metal compounds, alkaline earth metal compounds, phosphorus compounds, antistatic agents, light resistance agents, flame retardants, heat stabilizers, antioxidants, anti-gelling agents, surfactants, and the like. Moreover, in order to exhibit high transparency, it is also preferable not to contain particle|grains substantially in a polyester film. "Particles are not substantially contained" means, for example, in the case of inorganic particles, when the inorganic element is quantified by fluorescence X-ray analysis, the content is 50 ppm or less, preferably 10 ppm or less, particularly preferably the detection limit or less. means

It is preferable to provide an antireflection layer and/or a low reflection layer in at least one surface of the polyester film which is a polarizer protective film used for this invention. As for the surface reflectance of the antireflection layer used by this invention, 2.0 % or less is preferable. When it exceeds 2.0 %, it will become easy to visually recognize the color nonuniformity of a rainbow shape. The surface reflectance of the antireflection layer is more preferably 1.6% or less, still more preferably 1.2% or less, particularly preferably 1.0% or less. Although the lower limit in particular of the surface reflectance of an antireflection layer is not restrict|limited, For example, it is 0.01 %. A reflectance of 0% is most preferred. The reflectance can be measured by any method, for example, the light reflectance at a wavelength of 550 nm can be measured from the surface on the antireflection layer side using a spectrophotometer (Shimadzu Corporation, UV-3150).

The antireflection layer may be a single layer or multiple layers, and in the case of a single layer, if the thickness of the low refractive index layer containing a material having a lower refractive index than that of a plastic film (polyester film) is formed to be 1/4 wavelength of the light wavelength or an odd multiple thereof, the reflection prevention effect is obtained. In the case where the antireflection layer is multilayered, the antireflection effect can be obtained when the low-refractive-index layer and the high-refractive-index layer are alternately two or more layers, and the thickness of each layer is appropriately controlled and laminated. Moreover, a hard-coat layer may be laminated|stacked between antireflection layers as needed, and an antifouling|stain-resistant layer may be formed on a hard-coat layer.

Examples of the antireflection layer include those using a moth-eye structure. The moth-eye structure is a concave-convex structure with a pitch smaller than the wavelength formed on the surface, and this structure makes it possible to change the abrupt and discontinuous refractive index change at the interface with air into a continuous and gradually transitioning refractive index change. Accordingly, by forming the moth-eye structure on the surface, light reflection at the surface of the film is reduced. Formation of the antireflection layer using the moth-eye structure can be performed with reference to, for example, Japanese Patent Application Laid-Open No. 2001-517319.

As a method of forming an antireflection film, for example, a dry coating method in which an antireflection layer is formed on the surface of a substrate (polyester film) by vapor deposition or sputtering method, an antireflection coating liquid is applied to the surface of the substrate and dried to form an antireflection layer The wet coating method to be carried out, or the combined method which used both these together is mentioned. It will not specifically limit, if the said characteristic is satisfied about the composition of an antireflection layer, and its formation method.

A well-known thing can be used for a low reflection layer. For example, it is formed by a method of laminating at least one layer or more of a metal or oxide thin film by vapor deposition or sputtering, or a method of coating an organic thin film in one or multiple layers. As the low-reflection layer, a layer coated with an organic thin film having a lower refractive index than a polyester film or a hard coat layer laminated on the polyester film is preferably used. The surface reflectance of the low reflection layer is preferably less than 5%, more preferably 4% or less, still more preferably 3% or less, still more preferably 2% or less. Although a minimum is not specifically limited, About 0.8 % - 1.0 % is preferable.

An anti-glare function may be further provided to the antireflection layer and/or the low reflection layer. Thereby, rainbow_pattern|erythema can be suppressed further. That is, a combination of an antireflection layer and an antiglare layer, a combination of a low reflection layer and an antiglare layer, or a combination of an antireflection layer, a low reflection layer and an antiglare layer may be used. Especially preferably, it is a combination of a low reflection layer and a glare-proof layer. As the anti-glare layer, a known anti-glare layer can be used. For example, from a viewpoint of suppressing the surface reflection of a film, after laminating|stacking an anti-glare layer on a polyester film, the aspect which laminates|stacks an anti-reflection layer or a low-reflection layer on an anti-glare layer is preferable.

When forming an antireflection layer or a low reflection layer, it is preferable that a polyester film has an easily bonding layer on the surface. In that case, it is preferable to adjust the refractive index of an easily bonding layer from a viewpoint of suppressing the interference by reflected light so that it may become near a rising average of the refractive index of a reflection prevention layer, and the refractive index of a polyester film. A well-known method can be employ|adopted for adjustment of the refractive index of an easily bonding layer, For example, it can adjust easily by containing titanium, germanium, and other metal species in binder resin.

In order to make adhesiveness with a polarizer favorable to a polyester film, it is also possible to perform corona treatment, a coating process, a flame process, etc.

In the present invention, in order to improve the adhesiveness with the polarizer, it is preferable to have, on at least one side of the film of the present invention, an easily bonding layer mainly composed of at least one of a polyester resin, a polyurethane resin, or a polyacrylic resin. do. Here, a "main component" means a component 50 mass % or more among the solid components which comprise an easily bonding layer. As for the coating liquid used for formation of an easily bonding layer, the water-based coating liquid containing at least 1 sort(s) among a water-soluble or water-dispersible co-polyester resin, an acrylic resin, and a polyurethane resin is preferable. As these coating liquids, for example, the water-soluble or water-dispersible copolymerization disclosed in Japanese Patent No. 3567927, Japanese Patent No. 3589232, Japanese Patent No. 3589233, Japanese Patent No. 3900191, Japanese Patent No. 4150982, etc. A polyester resin solution, an acrylic resin solution, a polyurethane resin solution, etc. are mentioned.

The easy-to-adhesive layer can be obtained by applying the coating solution to one or both sides of a uniaxially stretched film in the longitudinal direction, drying at 100 to 150° C., and then stretching in the transverse direction. It is preferable to manage the application amount of the final easily bonding layer to 0.05-0.20 g/m<2>. Adhesiveness with the polarizer obtained as an application amount is less than 0.05 g/m<2> may become inadequate. On the other hand, when an application amount exceeds 0.20 g/m<2>, blocking resistance may fall. When providing an easily bonding layer on both surfaces of a polyester film, the application quantity of the easily bonding layer of both surfaces may be the same or different, and can each independently set within the said range.

It is preferable to add particles to the easily-adhesive layer in order to impart reverse activity. The average particle diameter of the fine particles is preferably 2 μm or less. When the average particle diameter of particle|grains exceeds 2 micrometers, particle|grains will fall off easily from a coating layer. Examples of the particles to be contained in the adhesion layer include titanium oxide, barium sulfate, calcium carbonate, calcium sulfate, silica, alumina, talc, kaolin, clay, calcium phosphate, mica, hectorite, zirconia, tungsten oxide, lithium fluoride, inorganic particles such as calcium fluoride; and organic polymer particles such as styrene, acrylic, melamine, benzoguanamine and silicone particles. These may be independently added to an easily bonding layer, and may be added in combination of 2 or more type.

In addition, as a method of apply|coating a coating liquid, a well-known method can be used. For example, the reverse roll coating method, the gravure coating method, the kiss coating method, the roll brush method, the spray coating method, the air knife coating method, the wire bar coating method, the pipe doctor method, etc. are mentioned, These methods are It can be performed individually or in combination.

In addition, the measurement of the average particle diameter of the said particle|grains is performed by the following method. The particles were photographed with a scanning electron microscope (SEM), and the maximum diameter (distance between the two most distant points) of 300 to 500 particles was measured at a magnification such that the size of one smallest particle was 2 to 5 mm. , the average value is taken as the average particle diameter.

The polyester film used as a polarizer protective film can be manufactured according to the manufacturing method of a general polyester film. For example, the polyester resin is melted and the unoriented polyester extruded into a sheet is stretched in the longitudinal direction at a temperature equal to or higher than the glass transition temperature by using the speed difference of the rolls, and then stretched in the transverse direction by a tenter and a method of performing heat treatment.

The polyester film used in the present invention may be a uniaxially oriented film or a biaxially oriented film, but when the biaxially oriented film is used as a polarizer protective film, rainbow-like color irregularity is not seen even when observed from directly above the film surface, When it observes from the diagonal direction, since rainbow-like color nonuniformity may be observed, caution is required.

When the film forming conditions of a polyester film are demonstrated concretely, 80-130 degreeC is preferable and, as for longitudinal stretch temperature and lateral stretch temperature, it is 90-120 degreeC especially preferably. In order to orient a film so that a slow axis may become a TD direction, 1.0-3.5 times are preferable and, as for a longitudinal stretch ratio, 1.0 times - 3.0 times are especially preferable. Moreover, as for the lateral draw ratio, 2.5 to 6.0 times are preferable, Especially preferably, they are 3.0 to 5.5 times. In order to orient a film so that a slow axis may become MD direction, as for a longitudinal stretch ratio, 2.5 to 6.0 times are preferable, Especially preferably, they are 3.0 to 5.5 times. Moreover, as for a lateral draw ratio, 1.0 times - 3.5 times are preferable, Especially preferably, they are 1.0 times - 3.0 times.

In order to control the refractive index and retardation of the fast axis direction of a polyester film in the said range, it is preferable to control the ratio of a longitudinal stretch ratio and a horizontal stretch ratio. Since the refractive index of the fast axis direction of a polyester film tends to exceed 1.62 when the difference of the draw ratio of length and breadth is too small, and it becomes difficult to make retardation high, it is unpreferable. Moreover, setting extending|stretching temperature low also makes low the refractive index of the fast-axis direction of a polyester film, and when making retardation high, it is a preferable correspondence. In the subsequent heat treatment, the treatment temperature is preferably 100 to 250°C, particularly preferably 180 to 245°C.

In order to suppress the fluctuation|variation of retardation, it is preferable that the thickness nonuniformity of a film is small. Since extending|stretching temperature and a draw ratio have a large influence on the thickness nonuniformity of a film, it is preferable to optimize film forming conditions also from a viewpoint of making thickness nonuniformity small. In particular, when a longitudinal draw ratio is made low in order to make retardation high, vertical thickness nonuniformity may become large. The thickness nonuniformity in the longitudinal direction has a region where the draw ratio becomes very bad in a certain range, so it is preferable to set the film forming conditions outside this range.

It is preferable that the thickness nonuniformity of a polyester film is 5.0 % or less, It is still more preferable that it is 4.5 % or less, It is still more preferable that it is 4.0 % or less, It is especially preferable that it is 3.0 % or less.

As mentioned above, in order to control retardation of a polyester film in a specific range, it can carry out by setting a draw ratio, extending|stretching temperature, and the thickness of a film suitably. For example, it becomes easy to obtain high retardation, so that a draw ratio is high, so that extending|stretching temperature is low, and the thickness of a film is thick. Conversely, it becomes easy to obtain low retardation, so that a draw ratio is low, so that a extending|stretching temperature is high, and the thickness of a film is thin. However, when the thickness of a film is made thick, thickness direction retardation becomes large easily. Therefore, it is preferable to set film thickness suitably in the range mentioned later. Moreover, in addition to retardation control, it is preferable to set the final film forming conditions in consideration of the physical property etc. required for a process.

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 with a film having a thickness of less than 15 µm, in principle, it is possible to obtain retardation of 1500 nm or more. However, in that case, the anisotropy of the mechanical property of a film becomes remarkable, it becomes easy to generate|occur|produce a tear, a tear, etc., and the practicability as an industrial material falls remarkably. A particularly preferable lower limit of the thickness is 25 µm. On the other hand, when the thickness upper limit of a polarizer protective film exceeds 300 micrometers, the thickness of a polarizing plate will become thick too much, and it is unpreferable. As for the upper limit of thickness from a practical viewpoint as a polarizer protective film, 200 micrometers is preferable. A particularly preferable upper limit of the thickness is 100 µm, which is equivalent to that of a general TAC film. In order to control retardation within the range of this invention even in the said thickness range, polyethylene terephthalate is suitable as polyester used as a film base material.

In addition, as a method of blending the UV absorber with the polyester film, a combination of known methods can be employed, for example, using a kneading extruder in advance, by blending the dried UV absorber with the polymer raw material to produce a master batch In addition, it can mix|blend by the method of mixing this predetermined masterbatch and a polymer raw material at the time of film forming, etc.

At this time, the concentration of the ultraviolet absorber in the master batch is preferably 5 to 30% by mass in order to uniformly disperse the ultraviolet absorber and to mix it economically. As conditions for producing a master batch, using a kneading extruder, the extrusion temperature is preferably higher than the melting point of the polyester raw material and extruded at a temperature of 290°C or lower for 1 to 15 minutes. At 290°C or higher, the amount of the ultraviolet absorber is large, and the viscosity of the masterbatch decreases. If the extrusion time is 1 minute or less, uniform mixing of the ultraviolet absorber becomes difficult. At this time, you may add a stabilizer, a color tone adjuster, and an antistatic agent as needed.

Moreover, it is preferable to make a polyester film into a multilayer structure of at least 3 layers or more, and to add a ultraviolet absorber to the intermediate|middle layer of a film. A film having a three-layer structure including an ultraviolet absorber in the intermediate layer can be specifically produced as follows. For the outer layer, polyester pellets alone, for the intermediate layer, the master batch containing the ultraviolet absorber and polyester pellets are mixed in a predetermined ratio, dried, and then fed to a known melt lamination extruder, and a sheet from a slit die It is extruded onto the top and allowed to cool and solidify on a casting roll to make an unstretched film. That is, by using two or more extruders, a three-layer manifold or a merging block (for example, a merging block having a square merging portion), the film layer constituting both outer layers and the film layer constituting the intermediate layer are laminated, and The three-layer sheet is extruded and cooled with a casting roll to make an unstretched film. Moreover, in order to remove the foreign material contained in the polyester of a raw material which becomes a cause of an optical defect, it is preferable to perform high-precision filtration at the time of melt extrusion. As for the filter particle size (95% of initial stage filtration efficiency) of the filter medium used for high-precision filtration of molten resin, 15 micrometers or less are preferable. When the filter particle size of a filter medium exceeds 15 micrometers, removal of the foreign material of 20 micrometers or more will become insufficient easily.

Example

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited by the following examples, and may be implemented with appropriate changes within a range suitable for the gist of the present invention, , they are all included in the technical scope of the present invention. In addition, the evaluation method of the physical property in a following example is as follows.

(1) Refractive index of polyester film

Using a molecular orientation meter (manufactured by Oji Keisoku Co., Ltd., MOA-6004 type molecular orientation meter), the direction of the slow axis of the film is determined, and a rectangle of 4 cm × 2 cm is formed so that the slow axis direction is parallel to the long side. It cut out and it was set as the sample for a measurement. About this sample, the refractive index of the biaxial orthogonal axis (refractive index in the slow axis direction: Ny, fast axis (refractive index in the direction perpendicular to the slow axis direction): Nx) and the refractive index (Nz) in the thickness direction were measured with an Abbe refractometer (manufactured by Atago Corporation). , NAR-4T, measurement wavelength 589 nm).

(2) Retardation (Re)

Retardation is a parameter defined by the product (ΔNxy × d) of the refractive index anisotropy (ΔNxy=|Nx-Ny|) of the biaxial orthogonal axes on the film and the film thickness d (nm), and is a measure of optical isotropy and anisotropy to be. Biaxial refractive index anisotropy (ΔNxy) was determined by the following method. Using a molecular orientation meter (manufactured by Oji Keisoku Co., Ltd., MOA-6004 type molecular orientation meter), the direction of the slow axis of the film is determined, and the direction of the slow axis is parallel to the long side of the sample for measurement, 4 cm x 2 cm A rectangle was cut out and it was set as the sample for a measurement. About this sample, the refractive index of the biaxial orthogonal axis (refractive index in the slow axis direction: Ny, the refractive index in the direction orthogonal to the slow axis direction: Nx) and the refractive index (Nz) in the thickness direction were measured by an Abbe refractometer (manufactured by Atago, NAR-4T). . The thickness d (nm) of the film was measured using an electric micrometer (manufactured by Fine Lup Co., Ltd., Miltron 1245D), and the unit was converted to nm. The retardation (Re) was calculated|required from the product (ΔNxy×d) of the anisotropy of the refractive index (ΔNxy) and the thickness d (nm) of the film.

(3) Retardation in thickness direction (Rth)

The thickness direction retardation is the average of the retardation obtained by multiplying the film thickness d by the two birefringence ΔNxz (=|Nx-Nz|) and ΔNyz (=|Ny-Nz|) when viewed from the cross section in the film thickness direction. This parameter indicates The thickness direction retardation (Rth) is obtained by calculating Nx, Ny, Nz and the film thickness d (nm) in the same manner as the retardation measurement, and calculating the average value of (ΔNxz×d) and (ΔNyz×d) did

(4) NZ coefficient

The values of Ny, Nx, and Nz obtained by (1) were substituted into NZ=|Ny-Nz|/|Ny-Nx|, and the value of the NZ coefficient was calculated|required.

(5) Measurement of emission spectrum of backlight light source

REGZA 43J10X manufactured by Toshiba Corporation was used for the liquid crystal display device used in each Example. When the emission spectrum of the backlight light source (white light emitting diode) of this liquid crystal display device was measured using a multi-channel spectrometer PMA-12 manufactured by Hamamatsu Photonics, emission spectra having peak tops around 450 nm, 535 nm and 630 nm were observed. . The half-width of each peak top (the half-width of the peak having the highest peak intensity in each wavelength region) was 17 nm for a 450 nm peak, 45 nm for a 535 nm peak, and 2 nm for a 630 nm peak, respectively. In addition, although this light source had a plurality of peaks in a wavelength region of 600 nm or more and 780 nm or less, the half-width was evaluated at a peak near 630 nm, which had the highest peak intensity in this region. In addition, the exposure time at the time of a spectrum measurement was 20 msec.

(6) reflectance

Using a spectrophotometer (manufactured by Shimadzu Corporation, UV-3150), the 5 degree reflectance at a wavelength of 550 nm was measured from the surface of the antireflection layer side (or the low reflection layer side). In addition, after applying black magic on the side opposite to the side on which the antireflection layer (or low reflection layer) of the polyester film was installed, a black vinyl tape (Kyohwa Vinyl Tape HF-737 Width 50mm) was attached and measured. .

(7) Observation of rainbow blotches

The liquid crystal display device obtained in each Example was visually observed in a dark place from the front and an oblique direction, and the presence or absence of generation|occurrence|production of a rainbow_pattern|erythema was judged as follows.

○: No rainbow stain was observed.

(triangle|delta): A little rainbow stain was observed.

×: rainbow stain was observed

× ×: rainbow blotches were observed remarkably

(Production Example 1-Polyester A)

When the temperature of the esterification reaction can was raised and reached 200° C., 86.4 parts by mass of terephthalic acid and 64.6 parts by mass of ethylene glycol were added thereto, and while stirring, 0.017 parts by mass of antimony trioxide as a catalyst, 0.064 parts by mass of magnesium acetate tetrahydrate, tri 0.16 mass parts of ethylamines were thrown in. Then, after pressurizing temperature rise and performing pressurization esterification on the conditions of 0.34 MPa of gauge pressure and 240 degreeC, the esterification reaction can was returned to normal pressure, and 0.014 mass parts of phosphoric acid was added. Then, it heated up at 260 degreeC over 15 minutes, and added 0.012 mass part of trimethyl phosphates. Subsequently, after 15 minutes, dispersion treatment was performed with a high-pressure disperser, and after 15 minutes, the obtained esterification product was transferred to a polycondensation reaction can, and polycondensation reaction was performed at 280°C under reduced pressure.

After completion of the polycondensation reaction, filtration is performed with a 95% Naslon filter having a cut diameter of 5 µm, extruded from a nozzle into a strand shape, and cooled using cooling water previously subjected to filtration (pore diameter: 1 µm or less) , solidified, 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 (hereinafter, abbreviated as PET (A)).

(Preparation Example 2-Polyester B)

10 parts by mass of dried ultraviolet absorbent (2,2'-(1,4-phenylene)bis(4H-3,1-benzoxazin-4-one), particle-free PET (A) (intrinsic viscosity) 0.62 dl/g) 90 parts by mass were mixed, and using a kneading extruder, a polyethylene terephthalate resin (B) containing an ultraviolet absorber was obtained (hereinafter, abbreviated as PET (B)).

(Preparation Example 3-Adjustment of Adhesive Modification Coating Solution)

Transesterification reaction and polycondensation reaction are performed by a conventional method, and as a dicarboxylic acid component (relative to the whole dicarboxylic acid component), terephthalic acid 46 mol%, isophthalic acid 46 mol%, and 5-sulfonate sodium isophthalate 8 A water-dispersible sulfonic acid metal base-containing co-polyester resin having a composition of 50 mol% ethylene glycol and 50 mol% neopentyl glycol (relative to the total glycol component) as a mol% and glycol component was prepared. Then, after mixing 51.4 parts by mass of water, 38 parts by mass of isopropyl alcohol, 5 parts by mass of n-butyl cellosolve, and 0.06 parts by mass of a nonionic surfactant, the mixture is heated and stirred, and when it reaches 77° C., the water-dispersible sulfonic acid After adding 5 mass parts of metal base containing co-polyester resin and stirring continuously until the lump of resin disappears, the resin aqueous dispersion is cooled to room temperature, and the water-dispersible co-polyester resin with a uniform solid content concentration of 5.0 mass % got the liquid. Furthermore, after dispersing 3 parts by mass of aggregate silica particles (manufactured by Fuji Sirisia Co., Ltd., Cyricia 310) in 50 parts by mass of water, 0.54 parts by mass of an aqueous dispersion of Cyricia 310 in 99.46 parts by mass of the water-dispersible co-polyester resin solution. parts, and 20 parts by mass of water was added while stirring to obtain an adhesive modifying coating liquid.

(Preparation Example 4 - Preparation of high refractive index coating agent)

80 parts by mass of methyl methacrylate, 20 parts by mass of methacrylic acid, 1 part by mass of azoisobutyronitrile, and 200 parts by mass of isopropyl alcohol are put into a reaction vessel, and reacted at 80° C. in a nitrogen atmosphere for 7 hours, a weight average molecular weight of 30000 A polymer solution of isopropyl alcohol was obtained. The obtained polymer solution was further diluted with isopropyl alcohol to 5 mass % of solid content, and the acrylic resin solution B was obtained. Then, the obtained acrylic resin solution B was mixed as follows, and the coating liquid for high refractive index layer formation was obtained.

・5 parts by mass of acrylic resin solution B

· 0.25 parts by mass of bisphenol A diglycidyl ether

0.5 parts by mass of titanium oxide particles having an average particle diameter of 20 nm

· Triphenylphosphine 0.05 parts by mass

・14.25 parts by mass of isopropyl alcohol

(Preparation Example 5 - Preparation of low refractive index coating agent)

2,2,2-trifluoroethyl acrylate (45 parts by mass), perfluorooctylethyl acrylate (45 parts by mass), acrylic acid (10 parts by mass), azoisobutyronitrile (1.5 parts by mass), methyl Ethyl ketone (200 mass parts) was thrown into the reaction container, it was made to react at 80 degreeC in nitrogen atmosphere for 7 hours, and the polymer methyl ethyl ketone solution with a weight average molecular weight of 20000 was obtained. The obtained polymer solution was diluted with methyl ethyl ketone to a solid content concentration of 5 mass % to obtain a fluoropolymer solution C. The obtained fluoropolymer solution C was mixed as follows, and the coating liquid for low-refractive-index layer formation was obtained.

· Fluoropolymer solution C 44 parts by mass

1,10-bis(2,3-epoxypropoxy)-2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9-hexadeca Fluorodecane

(manufactured by Kyoesa Chemical, Fluorite FE-16) 1 part by mass

0.1 parts by mass of triphenylphosphine

19 parts by mass of methyl ethyl ketone

(Preparation Example 6-Adjustment of anti-glare coating agent-1)

Unsaturated double bond-containing acrylic copolymer Cychroma P ACA-Z250 (manufactured by Daicel Chemical Industries, Ltd.) (49 parts by mass), cellulose acetate propionate CAP482-20 (number average molecular weight 75000) (manufactured by Eastman Chemicals) (3 parts by mass) ), acrylic monomer AYARAD DPHA (manufactured by Nippon Kayaku Corporation) (49 parts by mass), acrylic-styrene copolymer (average particle diameter of 4.0 µm) (manufactured by Sekisui Chemical Co., Ltd.) (2 parts by mass), Irgacure 184 (BASF) The mixed solvent of methyl ethyl ketone: 1-butanol = 3:1 was added as 35 mass % of solid component of the company make) (10 mass parts), and the coating liquid for glare-proof layer formation was obtained.

(Preparation Example 7-Adjustment of anti-glare layer coating agent-2)

Unsaturated double bond-containing acrylic copolymer Cychroma P ACA-Z250 (manufactured by Daicel Chemical Industries, Ltd.) (49 parts by mass), cellulose acetate propionate CAP482-0.5 (number average molecular weight 25000) (manufactured by Eastman Chemicals) (3 parts by mass) ), acrylic monomer AYARAD DPHA (manufactured by Nippon Kayaku Co., Ltd.) (49 parts by mass), acrylic-styrene copolymer (average particle diameter of 4.0 µm) (manufactured by Sekisui Chemical Industries, Ltd.) (4 parts by mass), Irgacure 184 (BASF) The mixed solvent of methyl ethyl ketone: 1-butanol = 3:1 was added as 35 mass % of solid component of the company make) (10 mass parts), and the coating liquid for glare-proof layer formation was obtained.

(Preparation Example 8-Adjustment of anti-glare layer coating agent-3)

Unsaturated double bond-containing acrylic copolymer Cychroma P ACA-Z250 (manufactured by Daicel Chemical Industries, Ltd.) (49 parts by mass), cellulose acetate propionate CAP482-0.2 (number average molecular weight 15000) (manufactured by Eastman Chemicals) (3 parts by mass) ), acrylic monomer AYARAD DPHA (manufactured by Nippon Kayaku Corporation) (49 parts by mass), acrylic-styrene copolymer (average particle diameter of 4.0 µm) (manufactured by Sekisui Chemical Co., Ltd.) (2 parts by mass), Irgacure 184 (BASF) The mixed solvent of methyl ethyl ketone: 1-butanol = 3:1 was added as 35 mass % of solid component of the company make) (10 mass parts), and the coating liquid for glare-proof layer formation was obtained.

(Polarizer Protective Film 1)

After drying under reduced pressure (1 Torr) at 135°C for 6 hours at 135°C for 6 hours, extruder 2 (for the intermediate layer II layer), and further, the PET (A) was dried by a conventional method and supplied to the extruder 1 (for the outer layer I layer and the outer layer III), respectively, and melted at 285°C. These two types of polymers are each filtered with a stainless steel sintered filter medium (nominal filtration precision of 10 µm particle 95% cut), laminated with a two-type three-layer merging block, extruded from a nozzle into a sheet form, and then electrostatic is applied Using the casting method, it was wound around a casting drum having a surface temperature of 30° C., cooled and solidified, and an unstretched film was made. At this time, the discharge amount of each extruder was adjusted so that the ratio of the thickness of the layer I, layer II, and layer III might be 10:80:10.

Then, the adhesive modifying coating solution was applied to both surfaces of the unstretched PET film by the reverse roll method so that the drying amount was 0.08 g/m 2 , and then dried at 80° C. for 20 seconds.

The unstretched film in which this application layer was formed was guide|guided|guided|guided|derived to the tenter drawing machine, it guide|induced to the hot air zone with a temperature of 125 degreeC, holding the edge part of a film with a clip, and it extended|stretched 4.0 times in the width direction. Subsequently, while maintaining the width stretched in the width direction, the treatment was performed at a temperature of 225°C for 10 seconds, followed by a 3.0% relaxation treatment in the width direction to obtain a uniaxially stretched PET film having a film thickness of about 100 µm.

The coating liquid for forming a high refractive index layer obtained by the above method was applied to one coated surface of the uniaxially stretched PET film, and dried at 150° C. for 2 minutes to form a high refractive index layer having a film thickness of 0.1 μm. On this high refractive index layer, the coating liquid for forming a low refractive index layer obtained by the above method is applied, dried at 150°C for 2 minutes, a low refractive index layer having a film thickness of 0.1 µm is formed, and an antireflection layer is laminated on a polarizer protective film got 1

(Polarizer Protective Film 2)

Except having changed the line speed and changing the thickness of the unstretched film, it carried out similarly to the polarizer protective film 1, and formed into a film, and the antireflection layer was laminated|stacked and the film thickness of about 80 micrometers polarizer protective film 2 was obtained.

(Polarizer Protective Film 3)

Except having changed the line speed and changing the thickness of the unstretched film, it carried out similarly to the polarizer protective film 1, and formed into a film, and the antireflection layer was laminated|stacked and the film thickness of the polarizer protective film 3 of about 60 micrometers was obtained.

(Polarizer Protective Film 4)

Except having changed the line speed and changing the thickness of the unstretched film, it carried out similarly to the polarizer protective film 1, and formed into a film, and obtained the polarizer protective film 4 with the film thickness of about 40 micrometers in which the antireflection layer was laminated|stacked.

(Polarizer Protective Film 5)

An anti-glare layer coating agent-1 is applied to one coated surface of the polarizer protective film produced by the same method as in the polarizer protective film 2, except that an antireflection layer is not provided so that the film thickness after curing is 8 µm, and 80 ° C. · Dry in the oven for 60 seconds. Thereafter, using an ultraviolet irradiation device (Fusion UV Systems Japan, light source H valve), ultraviolet rays were irradiated with an irradiation dose of 300 mJ/cm 2 , and an anti-glare layer was laminated. Then, the antireflection layer was laminated|stacked on the glare-proof layer by the method similar to the polarizer protective film 1, and the polarizer protective film 5 was obtained.

(Polarizer Protective Film 6)

Polarizer protective film 6 by laminating an anti-glare layer and anti-reflection layer in the same manner as in polarizer protective film 5 on one coated surface of the polarizer protective film produced by the same method as the polarizer protective film 3 except that the anti-reflection layer is not provided got it

(Polarizer protective film 7)

Anti-glare layer coating agent-2 is applied to one coated surface of the polarizer protective film produced by the same method as in the polarizer protective film 4 except that the antireflection layer is not provided so that the film thickness after curing is 8 µm, and 80 ° C. · Dry in the oven for 60 seconds. Thereafter, using an ultraviolet irradiation device (Fusion UV Systems Japan, light source H valve), ultraviolet rays were irradiated with an irradiation dose of 300 mJ/cm 2 , and an anti-glare layer was laminated. Then, the antireflection layer was laminated|stacked on the glare-proof layer by the method similar to the polarizer protective film 1, and the polarizer protective film 7 was obtained.

(Polarizer Protective Film 8)

The unstretched film produced by the same method as the polarizer protective film 1 was heated to 105° C. using a heated roll group and an infrared heater, and then stretched 3.3 times in the running direction in the roll group having a peripheral speed difference, and then the temperature It was guided to a hot air zone at 130° C., stretched 4.0 times in the width direction, and in the same manner as in the polarizer protective film 1, a polarizer protective film 8 having an antireflection layer laminated thereon was obtained.

(Polarizer Protective Film 9)

Except not providing an antireflection layer, it produced by the method similar to the polarizer protective film 1, and obtained the polarizer protective film 9 with a film thickness of about 100 micrometers.

(Polarizer Protective Film 10)

An anti-glare layer was laminated on one coated surface of the polarizer protective film produced by the same method as the polarizer protective film 8 except that an antireflection layer was not provided in the same manner as in the polarizer protective film 5 to obtain a polarizer protective film 10 (reflection The prevention layer is not laminated).

(Polarizer protective film 11)

An anti-glare coating agent-3 is applied to one coated surface of the polarizer protective film produced by the same method as in the polarizer protective film 1, except that an anti-reflection layer is not provided, so that the film thickness after curing is 8 µm, and 80 ° C. · Dry in the oven for 60 seconds. Then, using the ultraviolet irradiation apparatus (Fusion UV Systems Japan, light source H valve), the ultraviolet-ray was irradiated at the irradiation dose of 300 mJ/cm<2>, and the polarizer protective film 11 in which the glare-proof layer was laminated|stacked was obtained.

Using the polarizer protective films 1 to 11, a liquid crystal display device was produced as described later.

(Example 1)

A polarizer protective film 1 is attached to one side of a polarizer containing 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 (manufactured by Fuji Film Co., Ltd., thickness 80 μm) on the opposite side. was attached to prepare a polarizing plate 1. Moreover, the polarizer was laminated|stacked on the surface on which the antireflection layer of the polarizer protective film is not laminated|stacked, and the polarizing plate was produced.

The polarizing plate at the side of the visual recognition of REGZA 43J10X by Toshiba Corporation was substituted for the said polarizing plate 1 so that a polyester film might become the opposite side (distal side) to a liquid crystal cell, and the liquid crystal display device was produced. Moreover, it substituted so that the transmission axis direction of the polarizing plate 1 might become the same as the transmission axis direction of the polarizing plate before substitution.

(Example 2)

A polarizer protective film 2 is attached to one side of a polarizer containing 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 (manufactured by Fuji Film Co., Ltd., thickness 80 μm) on the opposite side. was attached to prepare a polarizing plate 2. Moreover, the polarizer was laminated|stacked on the surface on which the antireflection layer of the polarizer protective film is not laminated|stacked, and the polarizing plate was produced. Except having changed the polarizing plate 1 into the polarizing plate 2, it carried out similarly to Example 1, and produced the liquid crystal display device.

(Example 3)

A polarizer protective film 3 is attached to one side of a polarizer containing 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 (manufactured by Fuji Film Co., Ltd., thickness 80 μm) on the opposite side. was attached to prepare a polarizing plate 3 . Moreover, the polarizer was laminated|stacked on the surface on which the antireflection layer of the polarizer protective film is not laminated|stacked, and the polarizing plate was produced. Except having changed the polarizing plate 1 into the polarizing plate 3, it carried out similarly to Example 1, and produced the liquid crystal display device.

(Example 4)

A polarizer protective film 4 is attached to one side of a polarizer containing 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 (manufactured by Fuji Film Co., Ltd., thickness 80 μm) is attached to the opposite side. was attached to prepare a polarizing plate 4 . Moreover, the polarizer was laminated|stacked on the surface on which the antireflection layer of the polarizer protective film is not laminated|stacked, and the polarizing plate was produced. Except having changed the polarizing plate 1 into the polarizing plate 4, it carried out similarly to Example 1, and produced the liquid crystal display device.

(Example 5)

A polarizer protective film 4 is attached to one side of a polarizer containing PVA and iodine so that the transmission axis of the polarizer and the fast axis of the film are parallel, and a TAC film (manufactured by Fuji Film Co., Ltd., thickness 80 μm) is attached to the opposite side. was attached to prepare a polarizing plate 5. Moreover, the polarizer was laminated|stacked on the surface on which the antireflection layer of the polarizer protective film is not laminated|stacked, and the polarizing plate was produced. Except having changed the polarizing plate 1 into the polarizing plate 5, it carried out similarly to Example 1, and produced the liquid crystal display device.

(Example 6)

A polarizer protective film 5 is attached to one side of a polarizer containing 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 (manufactured by Fuji Film Co., Ltd., thickness 80㎛) on the opposite side. was attached to prepare a polarizing plate 6. Moreover, the polarizer was laminated|stacked on the surface on which the antireflection layer and the anti-glare layer of the polarizer protective film are not laminated|stacked, and the polarizing plate was produced. Except having changed the polarizing plate 1 into the polarizing plate 6, it carried out similarly to Example 1, and produced the liquid crystal display device.

(Example 7)

A polarizer protective film 6 is attached to one side of a polarizer containing 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 (manufactured by Fuji Film Co., Ltd., thickness 80 μm) is attached to the opposite side. was attached to prepare a polarizing plate 7. Moreover, the polarizer was laminated|stacked on the surface on which the antireflection layer and the anti-glare layer of the polarizer protective film are not laminated|stacked, and the polarizing plate was produced. Except having changed the polarizing plate 1 into the polarizing plate 7, it carried out similarly to Example 1, and produced the liquid crystal display device.

(Example 8)

A polarizer protective film 7 is attached to one side of a polarizer containing 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 (manufactured by Fuji Film Co., Ltd., thickness 80㎛) on the opposite side. was attached to prepare a polarizing plate 8. Moreover, the polarizer was laminated|stacked on the surface on which the antireflection layer and the glare-proof layer of the polarizer protective film are not laminated|stacked, and the polarizing plate was produced. Except having changed the polarizing plate 1 into the polarizing plate 8, it carried out similarly to Example 1, and produced the liquid crystal display device.

(Comparative Example 1)

A polarizer protective film 8 is attached to one side of a polarizer containing 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 (manufactured by Fujifilm Co., Ltd., thickness 80㎛) on the opposite side. was attached to prepare a polarizing plate 9. Moreover, the polarizer was laminated|stacked on the surface on which the antireflection layer of the polarizer protective film is not laminated|stacked, and the polarizing plate was produced.

The polarizing plate by the side of the visual recognition of REGZA 43J10X by Toshiba Corporation was substituted by the said polarizing plate 9 so that a polyester film might become the opposite side (distal side) to a liquid crystal cell, and the liquid crystal display device was produced. Moreover, it substituted so that the transmission axis direction of the polarizing plate 9 might become the same as the transmission axis direction of the polarizing plate before substitution.

(Comparative Example 2)

A polarizer protective film 9 is attached to one side of a polarizer containing 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 (manufactured by Fuji Film Co., Ltd., thickness 80 μm) on the opposite side. was attached to prepare a polarizing plate 10. Except having changed the polarizing plate 9 into the polarizing plate 10, it carried out similarly to the comparative example 1, and produced the liquid crystal display device.

(Comparative Example 3)

A polarizer protective film 10 is attached to one side of a polarizer containing 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 (manufactured by Fuji Film Co., Ltd., thickness 80㎛) on the opposite side. was attached to prepare a polarizing plate 11. Moreover, the polarizer was laminated|stacked on the surface on which the glare-proof layer of the polarizer protective film is not laminated|stacked, and the polarizing plate was produced. Except having changed the polarizing plate 9 into the polarizing plate 11, it carried out similarly to the comparative example 1, and produced the liquid crystal display device.

(Comparative Example 4)

A polarizer protective film 11 is attached to one side of a polarizer containing 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 (manufactured by Fuji Film Co., Ltd., thickness 80 μm) on the opposite side. was attached to prepare a polarizing plate 12. Moreover, the polarizer was laminated|stacked on the surface on which the glare-proof layer of the polarizer protective film is not laminated|stacked, and the polarizing plate was produced. Except having changed the polarizing plate 9 into the polarizing plate 12, it carried out similarly to the comparative example 1, and produced the liquid crystal display device.

About the liquid crystal display device obtained in each Example, the result of having measured rainbow_pattern|erythema observation is shown in the following Table 1.

The liquid crystal display device and the polarizing plate of this invention can ensure the favorable visibility by which generation|occurrence|production of the rainbow-like color unevenness was suppressed significantly from either angle, and the contribution to the industrial world is large.

Claims (5)

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 light source has a peak top of the emission spectrum in each wavelength region 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 780 nm or less, and the peak intensity of the highest peak in the wavelength region of 600 nm or more and 780 nm or less is half the peak. a white light emitting diode having an emission spectrum less than 5 nm in width;
At least one of the polarizing plates is one in which a polyester film is laminated on at least one surface of the polarizer,
The said polyester film has a retardation of 1500-30000 nm, The liquid crystal display device by which the antireflection layer and/or the low reflection layer are laminated|stacked on at least one surface of the said polyester film. According to claim 1, wherein the light emission spectrum of the backlight light source,
The half-width of the peak with the highest peak intensity in the wavelength region of 400 nm or more and less than 495 nm is 5 nm or more,
The half-width of the peak with the highest peak intensity in the wavelength region of 495 nm or more and less than 600 nm is 5 nm or more,
liquid crystal display. The liquid crystal display device according to claim 1 or 2, wherein a surface reflectance of the surface of the antireflection layer at a wavelength of 550 nm is 2.0% or less. It is a polarizing plate in which a polyester film is laminated on at least one side of the polarizer,
The polyester film has a retardation of 1500 to 30000 nm, and an antireflection layer and/or a low reflection layer are laminated on at least one surface of the polyester film,
400 nm or more and less than 495 nm, 495 nm or more and less than 600 nm, and each wavelength region of 600 nm or more and 780 nm or less has a peak top of the emission spectrum, respectively, and the half-width of the peak with the highest peak intensity in the wavelength region of 600 nm or more and 780 nm or less is less than 5 nm A polarizing plate for a liquid crystal display having a backlight light source including a white light emitting diode having an emission spectrum. The polarizing plate for a liquid crystal display device according to claim 4, wherein the surface reflectance of the surface of the antireflection layer at a wavelength of 550 nm is 2.0% or less.