KR101791320B1 - Vertical orentation type liquid display device having an improved reliable property and improved contrast ratio and method for preparing the same - Google Patents
Vertical orentation type liquid display device having an improved reliable property and improved contrast ratio and method for preparing the same Download PDFInfo
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- KR101791320B1 KR101791320B1 KR1020150191701A KR20150191701A KR101791320B1 KR 101791320 B1 KR101791320 B1 KR 101791320B1 KR 1020150191701 A KR1020150191701 A KR 1020150191701A KR 20150191701 A KR20150191701 A KR 20150191701A KR 101791320 B1 KR101791320 B1 KR 101791320B1
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1337—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/133528—Polarisers
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/13363—Birefringent elements, e.g. for optical compensation
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- G02F2001/133742—
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Abstract
The present invention relates to a vertical alignment type liquid crystal display device having excellent reliability of a contrast ratio including an asymmetric ester compound containing an aromatic group represented by the following formula (1), and a polarizing plate protective film of a cellulose ester phase difference film produced by a solution casting method, And a method for manufacturing the same.
[Chemical Formula 1]
T + [D + P] n + D
T is a residue of a toluic acid or a benzenecarboxylic acid residue, D is a propyleneglycol having 2 to 8 carbon atoms, neopentylglycol, diethyleneglycol, dipropyleneglycol Triethylene glycol, an alkylene glycol residue having 2 to 12 carbon atoms, an aryl glycol residue having 6 to 12 carbon atoms, or an oxyalkylene glycol residue having 4 to 12 carbon atoms, P is a phthalic acid having 2 to 10 carbon atoms Phthalic acid residue, an alkylene dicarboxylic acid residue having 4 to 12 carbon atoms, or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms, and n represents an integer of 1 or more.
Description
The present invention relates to a vertical alignment type liquid crystal display device having excellent reliability of a contrast ratio and a manufacturing method thereof. More particularly, the present invention relates to a cellulose ester phase retardation film produced by a solution casting method, which comprises a vertical alignment type liquid crystal display device having an excellent reliability of a contrast ratio including an asymmetric ester compound having an aromatic group represented by the following formula And a manufacturing method thereof.
[Chemical Formula 1]
T + [D + P] n + D
T is a residue of a toluic acid or a benzenecarboxylic acid residue, D is a propyleneglycol having 2 to 8 carbon atoms, neopentylglycol, diethyleneglycol, dipropyleneglycol Triethylene glycol, an alkylene glycol residue having 2 to 12 carbon atoms, an aryl glycol residue having 6 to 12 carbon atoms, or an oxyalkylene glycol residue having 4 to 12 carbon atoms, P is a phthalic acid having 2 to 10 carbon atoms Phthalic acid residue, an alkylene dicarboxylic acid residue having 4 to 12 carbon atoms, or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms, and n represents an integer of 1 or more.
In general, a liquid crystal display (hereinafter referred to as LCD) is advantageous in that it is thinner and lighter than a CRT (Cathode Ray Tube), can be driven at a low voltage, and consumes less power. Therefore, LCDs are used in various electronic devices such as televisions, notebook type personal computers (PCs), desktop type PCs, PDAs (portable terminals) and cellular phones.
In recent years, a vertical alignment type LCD (also referred to as a VA (Vertical Alignment) type) LCD using vertical alignment type liquid crystal (liquid crystal having a negative dielectric anisotropy) has a viewing angle characteristic It is widely used, in terms of superiority.
However, in this VA-LCD, the demand for power saving is further increased, and the light shielding part is minimized and the color filter on array (COA) is increasingly becoming more and more widely used. A method of increasing the transmittance of the polarizing plate as a power saving means has been proposed. However, when the transmittance of the polarizing plate is increased only, the degree of polarization decreases and the front contrast ratio (contrast) is lowered.
In order to solve this problem, a method of suppressing the depolarization caused by a polarizing film and a film (protective film) disposed between the polarizing film and the liquid crystal cell, such as a retardation film and a viewing angle enlarging film, is used.
Patent Document 1 and Non-Patent Document 1 below disclose that the front contrast ratio is increased by the constitution of the retardation film. These methods suggest a possibility that the front contrast ratio can be maintained even if the transmittance of the polarizing plate is increased. However, as a means of improving the front contrast ratio by these methods, the color shift becomes very large. Originally, a vertical alignment type liquid crystal display device has a small color shift, but this configuration is a method of eliminating the inherent advantages of a vertical alignment type liquid crystal display device.
In addition, the LCD manufactured using the conventional retardation film is resistant to high temperature and high humidity environments, and the contrast ratio of the LCD is also deteriorated when exposed to a high temperature and high humidity reliability environment.
(Patent Literature): Japanese Laid-Open Patent Publication No. 2010-54736
(Non-Patent Document): SID 2010 Digest of Technical Papers 55.1
Accordingly, it is an object of the present invention to provide a vertical alignment type liquid crystal display device and a method of manufacturing the same, which are excellent in reliability without lowering the contrast ratio even when exposed to a high temperature and high humidity environment.
According to an embodiment of the present invention, there is provided a vertical alignment type liquid crystal display device having excellent reliability of a contrast ratio,
A total cellulose acylate phase difference film having a total degree of substitution of acyl groups of 2.10 to 2.70 between the vertically aligned panel and the upper and lower polarizing plates, wherein the total sum of phase retardation values (Ro total ) 2, and the mixture was allowed to stand in a high-temperature and high-humidity chamber at a temperature of 60 ° C and a RH of 90% RH for 500 hours, the variation range of CR (Contrast Ratio) Wherein the cellulose ester phase difference film produced by the casting method comprises an asymmetric ester compound having an aromatic group represented by the following formula (1).
[Equation 1]
Ro total = R - C + R LC
&Quot; (2) "
40 nm < Rt total < 190 nm
In the formulas (1) and (2), R- C is the total retardation value in the plane direction of the negative C-plate satisfying the following equation (3)
&Quot; (3) "
R- C = (plane retardation value of the polarizing plate inner cellulose ester film) + (plane retardation value of the biaxial A plate) + (plane retardation value of the negative C plate)
R LC is the retardation value in the plane direction of the liquid crystal of the vertically oriented panel, and Ro total is the sum of R LC and R C.
&Quot; (4) "
? CR = {CR? Reliability? CR? Reliability?} / (CR? Reliability x 100 (%
Where CR is the white luminance / black luminance, which is the contrast ratio of the luminance when the LCD is in the black state and the luminance state is white.
[Chemical Formula 1]
T + [D + P] n + D
T is a residue of a toluic acid or a benzenecarboxylic acid residue, D is a propyleneglycol having 2 to 8 carbon atoms, neopentylglycol, diethyleneglycol, dipropyleneglycol Triethylene glycol, an alkylene glycol residue having 2 to 12 carbon atoms, an aryl glycol residue having 6 to 12 carbon atoms, or an oxyalkylene glycol residue having 4 to 12 carbon atoms, P is a phthalic acid having 2 to 10 carbon atoms Phthalic acid residue, an alkylene dicarboxylic acid residue having 4 to 12 carbon atoms, or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms, and n represents an integer of 1 or more.
The vertical bend-type liquid crystal display device according to the present invention includes an aromatic asymmetric ester compound represented by the above formula (1) so as to improve the high temperature and high humidity reliability of the cellulose ester phase difference film, The contrast ratio is not deteriorated and the reliability is excellent.
1 is an exploded perspective view of polarizer lamination.
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 illustrates an exploded perspective view of a polarizing plate lamination. A vertical alignment type liquid crystal display (hereinafter referred to as VA-LCD) according to an embodiment of the present invention includes polarizing
In FIG. 1, reference symbol a denotes an absorption axis of the polarizing plate, and b denotes an optical axis of the A-plate.
The cellulose-based polarizing plate according to one embodiment of the present invention comprises a polarizing plate protective film A (111, 123) having a film thickness of 20 to 100 μm containing a cellulose ester and a polarizing plate protective film B (113, 121) ; PVA film).
More specifically, the polarizing plate according to the present invention comprises a polarizing plate protective film A having a film thickness of 20 to 100 占 퐉 containing a cellulose ester,
The polarizing plate protective film B also serving as a retardation film having a film thickness of 20 to 60 탆 and containing cellulose ester having an acyl group total substitution degree of 2.1 to 2.7 has a thickness of 60 to 160 탆 sandwiching the polarizer.
In the present invention, the cellulose ester polarizing plate protective film A is preferably cellulose triacetate having an acetyl group total degree of substitution of 2.7 or more, and the polarizer preferably has polyvinyl alcohol and has a film thickness of 3 to 30 μm, The protective film B includes an asymmetric ester-based compound having an aromatic group represented by the following formula (1).
[Chemical Formula 1]
T + [D + P] n + D
T is a residue of a toluic acid or a benzenecarboxylic acid residue, D is a propyleneglycol having 2 to 8 carbon atoms, neopentylglycol, diethyleneglycol, dipropyleneglycol Triethylene glycol, an alkylene glycol residue having 2 to 12 carbon atoms, an aryl glycol residue having 6 to 12 carbon atoms, or an oxyalkylene glycol residue having 4 to 12 carbon atoms, P is a phthalic acid having 2 to 10 carbon atoms Phthalic acid residue, an alkylene dicarboxylic acid residue having 4 to 12 carbon atoms, or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms, and n represents an integer of 1 or more.
The method for producing the polarizing plate according to one embodiment of the present invention is not particularly limited, and can be manufactured by a general method. It is preferable that the back side of the cellulose ester film of the present invention is subjected to alkali saponification treatment and the treated cellulose ester film is immersed and stretched in an iodine solution to be bonded to at least one side of the polarizing film using a fully saponified polyvinyl alcohol aqueous solution . The cellulose ester film of the present invention may also be used on the other side, and another polarizing plate protective film may be used.
A polarizing film as a main component of the polarizing plate is an element that allows only light of a polarization plane in a certain direction to pass therethrough. A typical polarizing film currently known is a polyvinyl alcohol (PVA) polarizing film. This is a method of dyeing a polyvinyl alcohol film with iodine And dyed dichromatic dyes. The polarizing film is obtained by forming a film of a polyvinyl alcohol aqueous solution, uniaxially stretching the film, dyeing or dyeing it, uniaxially stretching it, and then durably treating it with a boron compound. The film thickness of such a polarizing film is 3 to 30 탆. A polarizing plate can be formed by bonding one side of the cellulose ester film of the present invention to the surface of the polarizing film. Preferably, it can be bonded by an aqueous adhesive mainly composed of completely saponified polyvinyl alcohol or the like.
The cellulose ester film of the polarizing plate protective film A is preferably cellulose triacetate having an acetyl group total degree of substitution of 2.7 or more. The cellulose ester film may be a cellulose solution containing triacetyl cellulose as a basic component, a UV absorber solution, The solution is mixed to prepare a casting stock solution, which is extruded, drawn and dried in the form of a sheet to form a film having a thickness of 20 to 100 탆.
More specifically, the cellulose solution is prepared by mixing 10 to 20 parts by weight of triacetylcellulose, 80 to 90 parts by weight of a mixed solvent obtained by mixing methylene chloride and methanol in a weight ratio of 9: 1, adding triphenylphosphate (TPP) and ethylphthalylethyl And 1 to 3 parts by weight of a plasticizer mixed with glycerol (EPEG) in a weight ratio of 3: 1. The ultraviolet absorber solution can be prepared, for example, by mixing Tinuvin 328 (manufactured by Ciba Specialty Chemicals) and Tinuvin 326 6 to 9 parts by weight of a mixed ultraviolet ray absorbent mixed in a ratio of 4: 1 in weight ratio and 90 to 95 parts by weight of a mixed solvent obtained by mixing methylene chloride and methanol in a weight ratio of 9: 1 . Further, in a dilute cellulose agarose solution containing the metal oxide is 9 for the cellulose solution of 25 to 35 parts by weight of silica (SiO 2) 1 to 2 parts by weight of methylene chloride and methanol in a weight ratio: a mixture solvent mixed with 160 To 80 parts by weight may be mixed to prepare a dilute cellulose solution containing silica (metal oxide).
A method for producing the cellulose ester film of the polarizing plate protective film A is as follows. 85 to 95 parts by weight of the cellulose solution, 3 to 5 parts by weight of a dilute cellulose solution containing the metal oxide and 2 to 5 parts by weight of the ultraviolet absorber solution are mixed to prepare a casting solution, In the form of extrusion. Next, the solvent of the casting stock solution is evaporated, followed by stretching and drying to form a cellulose film having a thickness in the range of 20 to 100 mu m.
The cellulose ester film of the polarizing plate protective film B according to one embodiment of the present invention is a cellulose ester film comprising 10 to 30 parts by weight of a cellulose ester having an acyl group total substitution degree of 2.10 to 2.70 and an asymmetric ester 2 to 8 parts by weight of a plasticizer, 70 to 90 parts by weight of a mixed solvent of methylene chloride and methanol in a weight ratio of 9: 1 are mixed to prepare a dilute cellulose solution containing silica as a metal oxide.
Next, 2 to 10 parts by weight of the particulate additive liquid is added to 100 parts by weight of the main dope solution, and then the mixture is uniformly softened on a support by using a belt softener, and the solvent is evaporated, followed by stretching and drying. Can be prepared.
For example, the entire process for producing such a cellulose ester-based film is performed by extruding the main dope liquid onto the surface of the belt through a die and applying it in a sheet form, evaporating the solvent present in the dope liquid, (MD) and the transverse direction (TD) in the tenter (first drying section), evaporation of the residual solvent in the second drying section, and then the film is obtained through the winding process in the winder have.
Here, the die may be a normal T-die, and the belt is preferably a stainless steel conveyor belt, for example, a high-temperature band support which forms a film by drying while transferring the dope liquid. The thickness of such a cellulose ester film (for example, the final thickness after stretching and drying) can be appropriately adjusted as necessary, but according to the present invention, it is preferably in the range of 20 to 60 탆.
The polarizing plate protective film B produced by the above method also serves as a retarder, and has in-plane retardation Ro of 40 to 60 nm and retardation Rth in the thickness direction of 110 to 140 nm.
Ro = (nx-ny) xd
Rth = ((nx + ny) / 2-nz) xd
Nx and ny represent refractive indices in the in-plane direction of the film, nz represent refractive indices in the thickness direction of the film, nx > = ny, , And d represents the thickness (nm) of the film. The retardation values Ro and Rt were measured at 590 nm under the environment of 23 ° C and 55% RH using an AxoScan (OPMF-1, Axometrics) optical measuring instrument.
The cellulose esters can be generally used alone or in combination with cellulose esters synthesized from cellulose ester synthesized from linter pulp, wood pulp and kenaf pulp, and other raw materials.
According to the present invention, the cellulose ester optical film may contain a specific plasticizer, and the plasticizer is an asymmetric ester plasticizer containing an aromatic group represented by the general formula (1). The cellulose ester film may be a barrier film of a cellulose ester film before / And is particularly preferable in setting the characteristics to a predetermined range.
Specific compounds of the aromatic-containing asymmetric ester compound according to the present invention are as follows, but the present invention is not limited thereto.
(2)
Mw = 400.4
(3)
Mw = 456.5
[Chemical Formula 4]
Mw = 460.5
[Chemical Formula 5]
Mw = 516.6
[Chemical Formula 6]
Mw = 548.6
(7)
Mw = 606.6
[Chemical Formula 8]
Mw = 690.8
[Chemical Formula 9]
Mw = 696.7
[Chemical formula 10]
Mw = 780.9
(11)
Mw = 828.9
According to the present invention, the polarizing plate can be produced by the following method. The
More specifically, a step of obtaining a saponified cellulose ester film on the side bonded to the polarizer (first step); Immersing the polarizing film in a polyvinyl alcohol adhesive tank (second step); A step of lightly wiping off excess adhesive adhered to the polarizing film in the step 2, placing the cellulose ester film on the cellulose ester film treated in the step 1 (third step); Joining the cellulose
1, polarizer protective film B (113, 121) is coated with a pressure-sensitive adhesive and laminated on a glass substrate.
In the cellulose ester polarizing plate protective film of the present invention, especially when the polarizing plate protective film B contains the plasticizer proposed in the present invention and is within the range of the thickness and degree of substitution of the cellulose ester film, the reliability of the polarizing plate before and after the reliability treatment of the polarizing plate is excellent Able to know.
In the VA-LCD according to the embodiment of the present invention, the polarizer protective film B is coated with a pressure-sensitive adhesive on the polarizing plate protective film B as described above, And then attaching an up / down polarizer. That is, the polarizing plate protective films A 111 and 123 and the polarizing plate
In the polarizing plate according to the present invention, VA-LCD satisfies the above-mentioned conditions (1) and (2) and the total sum Ro (Ro total ) of the retardation values in the plane direction satisfies the above- After being left for a period of time, the variation range of the contrast ratio can satisfy the condition of the expression (4).
[Equation 1]
Ro total = R - C + R LC
&Quot; (2) "
40 nm < Rt total < 190 nm
In the formulas (1) and (2), R- C is the total retardation value in the plane direction of the negative C-plate satisfying the following equation (3)
&Quot; (3) "
R- C = (plane retardation value of the polarizing plate inner cellulose ester film) + (plane retardation value of the biaxial A plate) + (plane retardation value of the negative C plate)
R LC is the retardation value in the plane direction of the liquid crystal of the vertically oriented panel, and Ro total is the sum of R LC and R C.
&Quot; (4) "
? CR = {CR? Reliability? CR? Reliability?} / (CR? Reliability x 100 (%
Where CR is the white luminance / black luminance, which is the contrast ratio of the luminance when the LCD is in the black state and the luminance state is white.
When the VA-LCD is manufactured using the cellulose ester film containing the plasticizer proposed in the present invention in the constitution of the cellulose ester polarizing plate protective film of the present invention, particularly in the polarizing plate protective film B, the reliability of the contrast ratio before and after the reliability processing of the LCD great.
Hereinafter, the present invention will be described in more detail with reference to examples, but the following examples are for illustrative purposes only and the present invention is not limited thereto.
Example 1
Preparation of Polarizer Protective Film A-Cellulose Ester Film
(1) Preparation of cellulose solution
16 parts by weight of triacetyl cellulose having an average degree of acetyl substitution (DS) of 2.86, 82 parts by weight of a mixed solvent obtained by mixing methylene chloride and methanol in a ratio of 9: 1 (weight ratio), triphenylphosphate (TPP) And 2 parts by weight of a plasticizer mixed with ethyl glycolate (EPEG) at a ratio of 3: 1 (weight ratio) were mixed to prepare a cellulose solution.
(2) Preparation of ultraviolet absorber solution
7.5 parts by weight of a mixed ultraviolet light absorber obtained by mixing Tinuvin 328 (manufactured by Ciba Specialty) and Tinuvin 326 (manufactured by Ciba Specialty) in a ratio of 4: 1 (weight ratio) and 9 parts by weight of methylene chloride and methanol (Weight ratio) were mixed to prepare an ultraviolet absorber solution.
(3) Preparation of Diluted Cellulose Solution Containing Metal Oxide
The cellulose solution of 28.5 parts by weight of silica (SiO 2) 1.5 parts by weight of methylene chloride and methanol 9: Preparation of diluted cellulose solution by mixing 1 (weight ratio) parts of a mixed solvent of 70 parts by weight mixed with comprises silica (metal oxide) Respectively.
(4) Production of film of cellulose
93 parts by weight of the cellulose solution, 4 parts by weight of the dilute cellulose solution containing the metal oxide and 3 parts by weight of the ultraviolet absorber solution were mixed to prepare a casting stock solution. Then, on the surface of the metal belt, a sheet having a thickness of 400 μm and a width of 1800 mm ). While the metal belt was being rotated, the solvent of the casting stock solution was evaporated, stretched and dried to form a cellulose film (TF-40-1) having a thickness of 40 占 퐉. The light transmittance T (380 nm) of the prepared cellulose film at 380 nm wavelength was 2.62%, the light transmittance T (620 nm) at 620 nm was 92.8%, and the b * value was 0.60 in the CIE colorimetric system.
Preparation of Polarizer Protective Film B-Cellulose Ester Film
( 1) Preparation of cellulose solution (initiator solution)
For the cellulose ester, acetyl group of 2.1, butyryl group of 0.2 and total degree of substitution of 2.3 was used, and as a plasticizer, 2 parts by weight of a terminal asymmetric plasticizer having the following chemical formula 2 was used.
(2)
(2) Preparation of Dilute Solution Containing Metal Oxide
20.0 parts by weight of the cellulose solution, 1.5 parts by weight of silica (SiO 2 ), and 78.5 parts by weight of a mixed solvent obtained by mixing methylene chloride and methanol in a weight ratio of 9: 1 were mixed to prepare a dilute cellulose solution containing silica (metal oxide) Respectively.
(3) Production of film of cellulose
100 parts by mass of the main doping liquid and 5 parts by mass of the fine particulate addition liquid were added, sufficiently mixed (Doped A) by an inline mixer, and then uniformly plied to a stainless steel band support of 2000 mm in width using a belt smoothing device. The solvent was evaporated on the stainless steel band support and peeled off from the stainless band support. Then, both ends of the web were held with a tenter and stretched so that the draw ratio in the (TD) direction was 1.3 times in a temperature environment of 170 ° C. After the stretching, the stretching was maintained for a few seconds, the tensile force in the width direction was relaxed, the stretching was performed in the width direction, the stretching was continued for 35 minutes in the drying section set at 110 DEG C, A cellulose ester film having a thickness of 40 탆 and a polarizing plate protective film B having a knurling width of 10 mm and a height of 8 탆 was prepared.
The cellulose ester film thus obtained was a retardation film having an in-plane retardation value Ro of 40 to 60 nm and a retardation value Rth in the thickness direction of 110 to 140 nm according to the following measurement.
&Quot; (5) "
Ro = (nx-ny) xd
Rth = ((nx + ny) / 2-nz) xd
Nx and ny represent refractive indices in the in-plane direction of the film, nz represent refractive indices in the thickness direction of the film, nx > = ny, , And d represents the thickness (nm) of the film. The retardation values Ro and Rth were measured at 590 nm under the environment of 23 ° C and 55% RH using an AxoScan (OPMF-1, Axometrics) optical measuring instrument.
Production of Polarizer
First, a polarizer was produced using the following PVA film.
(1) Polarizer: Production of PVA film
The polyvinyl alcohol film having a thickness of 120 占 퐉 was uniaxially stretched (temperature: 110 占 폚, stretching magnification: 5 times). This was immersed in an aqueous solution containing 0.075 g of iodine, 5 g of potassium iodide and 100 g of water for 60 seconds and then immersed in an aqueous solution at 68 DEG C containing 6 g of potassium iodide, 7.5 g of boric acid and 100 g of water. This was washed with water and dried to obtain a polarizer (PF-1).
(2) Production of Polarizer
Next, according to the following steps 1 to 5, the polarizer and the cellulose ester film as the polarizing plate protective film B and the cellulose ester as the polarizing plate protective film A were bonded to the back side as a polarizing plate protective film according to the following process To prepare a polarizing plate.
And immersed in a 2 mol / L sodium hydroxide solution at 60 DEG C for 90 seconds, followed by washing with water and drying to obtain a cellulose ester film in which the side bonded to the polarizer was saponified (Step 1).
The polarizing membrane was immersed in a polyvinyl alcohol adhesive tank (bath) having a solid content of 2 mass% for 1 to 3 seconds (Step 2).
In step 2, the excess adhesive adhered to the polarizing film was lightly wiped off and placed on the cellulose ester film treated in step 1 (step 3).
The cellulose ester film laminated in Step 3, the polarizer and the back side cellulose ester film were bonded at a pressure of 20 to 30 N / cm 2 and a conveying speed of about 2 m / min (Step 4).
A sample obtained by bonding the polarizer, the cellulose ester film and the back side cellulose ester film prepared in Step 4 in a dryer at 80 占 폚 was dried for 2 minutes to prepare a polarizing plate (Step 5).
The prepared polarizer was coated with a pressure-sensitive adhesive on the B-side of the polarizing plate protective film, and then laminated on a glass substrate (100 in Fig. 1) having a thickness of 0.5 mm. In this state, the degree of polarization was measured using a spectrophotometer (Jasco, Model V7100) optical measuring instrument under an environment of 23 ° C and 55% RH.
The polarizing plate laminated on the
Manufacturing of VA-LCD
(1) A pressure-sensitive adhesive was coated on the polarizing plate protective film B side of the prepared polarizing plate (Pol-1), and then an upper / lower polarizing plate was attached so that the polarizing plate protective film B was directed toward the vertically- To produce a VA-LCD. The polarizer protective films A 111 and 123 and the polarizer
The vertically aligned
In the same manner, a vertical alignment -LCD was manufactured using a polarizing plate (Pol-2), and the luminance was measured using the same equipment under the same conditions.
The prepared VA-LCD was allowed to stand in a reliable environment at 60 ° C and 90% RH for 500 hours using a high temperature and high humidity chamber, and then taken out from the high temperature and high humidity chamber and subjected to the same equipment under conditions of 23 ° C. and 55% RH The brightness of the black and white states was measured to observe the change of the contrast ratio before and after the reliability environmental treatment. As shown in the results of Table 7, when the VA-LCD is manufactured using the cellulose ester film containing the plasticizer proposed in the present invention in the constitution of the cellulose ester polarizing plate protective film of the present invention, particularly in the polarizing plate protective film B, The reliability of the contrast ratio before and after the reliability process is excellent.
Examples 2 to 15
A cellulose ester film A was prepared in the same manner as in Example 1 except that the cellulose ester, the plasticizer, and the dope solution as shown in the following Tables 1 to 4 were used. Cellulose films (TF-40-1 and TF-60-1) having thicknesses of 40 and 60 mu m were formed by changing the thickness as shown in Table 5 in the same manner as in Example 1. The light transmittance T (380 nm) of the prepared cellulose film at 380 nm wavelength was 2.56%, the light transmittance T (620 nm) at 620 nm was 92.7%, and the b * value was 0.59 in the CIE colorimetric system. Further, the cellulose ester film B having the film thicknesses of 30, 40 and 50 탆 was prepared after the main dopes (B to E) were prepared as shown in Tables 1 to 4 below, and the properties of the polarizer thus produced were measured Was measured in the same manner as in Example 1 above.
The polarizers were prepared in the same manner as in Example 1 using the PVA film as shown in Table 5 below, and the reliability of the prepared polarizer was measured. The results are shown in Table 6 below.
The VA-LCD was manufactured in the same manner as in Example 1, and the results are shown in Table 7.
* See Table 2, ** See Table 3
Cellulose ester film No.
Comparative Examples 1 to 8
A cellulose ester film A was prepared in the same manner as in Example 1 except that the cellulose ester, the plasticizer, and the dope solution as shown in Tables 1 to 4 were used. Cellulose films (TF-40-1 and TF-60-1) having thicknesses of 40 and 60 占 퐉 were prepared in the same manner as in Example 1 except that the thickness was changed as shown in Table 5. The light transmittance T (380 nm) of the prepared cellulose film at 380 nm wavelength was 2.56%, the light transmittance T (620 nm) at 620 nm was 92.7%, and the b * value was 0.59 in the CIE colorimetric system. The cellulose ester film B was prepared in the same manner as in Example 1, except that the main dope liquids (F to I) were prepared as shown in Tables 1 to 4, and then the cellulose ester film B was prepared.
The polarizers were prepared in the same manner as in Example 1 using the PVA film in the same manner as in Table 5, and the reliability of the prepared polarizer was measured. The results are shown in Table 6 above.
The VA-LCD was manufactured in the same manner as in Example 1, and the results are shown in Table 7.
It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as defined in the appended claims. There will be.
100: transparent glass substrate
110, 120: polarizer
111, 123: protective film A
113,121: Protective film B
112, 122: Polarizer
Claims (9)
And a cellulose ester polarizing plate protective film (B) having a total degree of substitution of acyl groups of 2.10 to 2.70 between the vertically aligned liquid crystal panel and polarizing plates on the upper and lower sides, wherein a total sum (Ro total ) Satisfying the conditions of equations (1) and (2) and allowing the high-temperature and high-humidity chamber to stand in a reliability environment of 60 ° C and 90% RH for 500 hours, the variation range of the contrast ratio satisfies the following formula (4) Wherein the cellulose ester polarizing plate protective film (B) comprises an asymmetric ester compound having an aromatic group represented by at least one of the following formulas (2) to (11).
[Equation 1]
Ro total = R - C + R LC
&Quot; (2) "
40 nm < Rt total < 190 nm
In the formulas (1) and (2), R- C is the total retardation value in the plane direction of the negative C-plate satisfying the following equation (3)
&Quot; (3) "
R- C = (plane retardation value of the polarizing plate inner cellulose ester film) + (plane retardation value of the biaxial A plate) + (plane retardation value of the negative C plate)
R LC is the retardation value in the plane direction of the liquid crystal of the vertically oriented panel, and Ro total is the sum of R LC and R C.
&Quot; (4) "
? CR = {CR? Reliability? CR? Reliability?} / (CR? Reliability x 100 (%
Where CR is the white luminance / black luminance, which is the contrast ratio of the luminance when the LCD is in the black state and the luminance state is white.
(2)
,
(3)
,
[Chemical Formula 4]
,
[Chemical Formula 5]
,
[Chemical Formula 6]
,
(7)
,
[Chemical Formula 8]
,
[Chemical Formula 9]
,
[Chemical formula 10]
,
(11)
.
&Quot; (5) "
Ro = (nx-ny) xd
Rth = {(nx + ny) / 2-nz} xd
Herein, nx, ny and nz represent refractive indices of principal axes x, y and z of the refractive index ellipsoid, nx and ny represent refractive indices in the in-plane direction of the film, nz represent refractive indices in the thickness direction of the film, , d represents the thickness (nm) of the film, and is a value measured at a wavelength of 550 nm under an environment of 23 deg. C and 55% RH.
Preparing a cellulose film of a polarizing plate protective film A having a thickness in the range of 20 to 100 mu m;
An asymmetric ester plasticizer containing an aromatic group represented by at least one of the following formulas (2) to (11), a mixed solvent of methylene chloride and methanol, a dilution containing silica as a metal oxide Preparing a cellulose ester film of the polarizing plate protective film B from a cellulose solution by softening, evaporating, stretching and drying the solvent;
Bonding the polarizing plate protective film A and the other surface of the polarizing plate protective film B to one side of the polarizer under a constant pressure; And
Wherein the polarizing plate protective film (A) and the polarizing plate protective film (B) are bonded to the upper and lower surfaces of the vertically aligned liquid crystal panel, respectively.
(2)
,
(3)
,
[Chemical Formula 4]
,
[Chemical Formula 5]
,
[Chemical Formula 6]
,
(7)
,
[Chemical Formula 8]
,
[Chemical Formula 9]
,
[Chemical formula 10]
,
(11)
.
&Quot; (5) "
Ro = (nx-ny) xd
Rth = {(nx + ny) / 2-nz} xd
Herein, nx, ny and nz represent refractive indices of principal axes x, y and z of the refractive index ellipsoid, nx and ny represent refractive indices in the in-plane direction of the film, nz represent refractive indices in the thickness direction of the film, , d represents the thickness (nm) of the film, and is a value measured at a wavelength of 550 nm under an environment of 23 deg. C and 55% RH.
[Equation 1]
Ro total = R - C + R LC
&Quot; (2) "
40 nm < Rt total < 190 nm
In the formulas (1) and (2), R- C is the total retardation value in the plane direction of the negative C-plate satisfying the following equation (3)
&Quot; (3) "
R- C = (plane retardation value of the polarizing plate inner cellulose ester film) + (plane retardation value of the biaxial A plate) + (plane retardation value of the negative C plate)
R LC is the retardation value in the plane direction of the liquid crystal of the vertically oriented panel, and Ro total is the sum of R LC and R C.
&Quot; (4) "
? CR = {CR? Reliability? CR? Reliability?} / (CR? Reliability x 100 (%
Where CR is the white luminance / black luminance, which is the contrast ratio of the luminance when the LCD is in the black state and the luminance state is white.
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Citations (3)
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JP2010054736A (en) | 2008-08-27 | 2010-03-11 | Fujifilm Corp | Retardation film and polarizing plate using the same, liquid crystal display device |
JP2014149325A (en) | 2013-01-31 | 2014-08-21 | Konica Minolta Inc | Method for manufacturing optical film, method for manufacturing polarizing plate and method for manufacturing liquid crystal display device |
WO2014132691A1 (en) | 2013-02-26 | 2014-09-04 | コニカミノルタ株式会社 | Polarizing sheet, polarizing sheet production method and liquid crystal display device |
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JP2010054736A (en) | 2008-08-27 | 2010-03-11 | Fujifilm Corp | Retardation film and polarizing plate using the same, liquid crystal display device |
JP2014149325A (en) | 2013-01-31 | 2014-08-21 | Konica Minolta Inc | Method for manufacturing optical film, method for manufacturing polarizing plate and method for manufacturing liquid crystal display device |
WO2014132691A1 (en) | 2013-02-26 | 2014-09-04 | コニカミノルタ株式会社 | Polarizing sheet, polarizing sheet production method and liquid crystal display device |
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