CN101165557A - Liquid crystal display and method of manufacturing the same - Google Patents

Abstract

The invention relates to a liquid crystal display device and manufacturing method for improving a burning phenomenon of an image, wherein a polymerizable component contained in a liquid crystal layer is polymerized while voltage to be applied to the liquid crystal is adjusted to regulate the alignment direction of liquid crystal molecules when the polymerizable component is polymerized. In a method of manufacturing a liquid crystal display in which a liquid crystal composition including a polymeric component that is optically or thermally polymerized is sealed between substrates and in which the polymeric component is polymerized while applying a voltage to the liquid crystal composition to regulate the direction of alignment of liquid crystal molecules during driving, a configuration is employed such that a polymerization initiator in the liquid crystal composition has a concentration x that satisfies 0<=x<=0.002 (% by weight).

Description

Liquid crystal disply device and its preparation method

The application is that application number is the dividing an application of application for a patent for invention of " 03102100.X ".The applying date of this application for a patent for invention is " on January 30th, 2003 ".Denomination of invention is " Liquid crystal disply device and its preparation method ".

Technical field

The present invention relates to following liquid crystal indicator (LCD) and manufacture method thereof: sealing contains by light or heat and carries out the liquid crystal material of the polymerism composition (monomer and oligomer etc.) of polymerization between substrate, (comprises that applying voltage is 0 situation in the voltage that applies on being adjusted at liquid crystal layer.Below, abbreviate " when applying voltage " as required as) the polymerization composition, form condensate, the direction of orientation of liquid crystal molecule when driving according to polymeric orientation limitations power regulation.

Background technology

In the past, as the liquid crystal indicator that utilizes active matrix, liquid crystal material with positive permittivity anisotropic properties is being oriented to and the real estate level under dark state, and (Twisted Nematic: twisted-nematic) liquid crystal indicator of mode has obtained extensive utilization to carry out TN that 90 degree reverse between opposing substrates.The liquid crystal indicator of this TN pattern has the problem of viewing angle characteristic difference, has carried out all research in order to improve viewing angle characteristic.

As the liquid crystal indicator of the liquid crystal indicator that on viewing angle characteristic, is superior to existing TN pattern, be well known that the liquid crystal indicator (being designated hereinafter simply as IPS-LCD) that makes liquid crystal horizontal alignment with positive permittivity anisotropic properties and the IPS pattern that applies the transverse electric field (In-Plane-Switching mode).But, because IPS-LCD switches liquid crystal molecule by comb poles in surface level, and obvious decline of numerical aperture meeting that passes through this comb poles pixel, so need the back light unit of highlight strength.

To this, a kind of liquid crystal vertical-tropism with negative electricity capacity rate anisotropic properties that makes, multizone vertical alignment mode (the Multi-domain Vertical Alignment mode) liquid crystal indicator (being designated hereinafter simply as MVA-LCD) that is provided with the portion that removes (slit) of dike (wire projection) and electrode as orientation limitations with structure on substrate is by known to the people.Because MVA-LCD is provided with the orientation limitations structure, so even alignment films is not carried out friction treatment, can the liquid crystal aligning direction control when applying voltage be a plurality of orientation also, viewing angle characteristic be good.

But even make the decline of the substantial numerical aperture of pixel not have the numerical aperture of the comb poles of IPS-LCD to descend manyly by projection on the MVA-LCD and slit, the transmittance of its plate still is lower than the LCD of TN pattern.Therefore, in fact MVA-LCD and IPS-LCD are not suitable for requiring now the notebook type PC of low power consumption.

And the shortcoming of existing MVA-LCD is that the brightness of white is low, demonstration is darker.This mainly is therefore to generate concealed wire because form the border that orientation cuts apart above above the projection and slit, so the transmittance step-down when white shows seems darker.In order to improve this shortcoming, though also can fully widen being provided with at interval of projection and slit, but owing to reduce with the projection of structure and the quantity in slit as orientation limitations, even so on liquid crystal, apply assigned voltage, also can make orientation stable, produce elongated problem of response time because of the needs elapsed time.

In order to improve this problem, realize high brightness and the MVA-LCD that can respond fast, a kind of method of direction of orientation of the liquid crystal molecule when utilizing the condensate regulation to drive is provided.In the method for the direction of orientation of the liquid crystal molecule when utilizing the condensate regulation to drive, be sealed with liquid crystal material between substrate, this liquid crystal material has mixed polymerism compositions (being designated hereinafter simply as monomer) such as monomer and oligomer in liquid crystal.Polymerization single polymerization monomer makes its condensateization under the state that voltage makes liquid crystal molecules tilt applying between substrate.Like this, even remove the liquid crystal layer that the voltage that applies also can obtain tilting with the tilt angle of regulation.Monomer can be selected the material that carries out polymerization by heat or light (ultraviolet ray).

But, among the MVA-LCD that the method for the direction of orientation of the liquid crystal molecule when passing through with the driving of condensate regulation is made, if show identical image for a long time, also can see the burn phenomenon of residual previous image (fluorescent screen images keeps imagesticking) even demonstration then can occur changing.Therefore, the problem that display quality reduces appears.

Summary of the invention

The object of the present invention is to provide following Liquid crystal disply device and its preparation method: the image burn phenomenon that method produced that can improve the liquid crystal molecular orientation direction when utilizing the condensate regulation to drive, simple and easy and positively improve display characteristic, realize the demonstration of high reliability.

Above-mentioned purpose realizes by a kind of liquid crystal indicator that is sealed with liquid crystal material between two relative substrates.This display device is characterised in that above-mentioned liquid crystal material comprises polymerism composition, polymerization atarting material, the liquid-crystal composition that carries out polymerization by light or heat, and the concentration x of above-mentioned polymerization atarting material is 0≤x≤0.002 (wt%).

Description of drawings

Fig. 1 is the figure of the Liquid crystal disply device and its preparation method of diagrammatic illustration first embodiment of the invention.

Fig. 2 is the figure that is illustrated in the operation of irradiation ultraviolet radiation when applying voltage on the liquid crystal layer of LCD plate.

Fig. 3 is the figure of other Liquid crystal disply device and its preparation methods of diagrammatic illustration first embodiment of the invention.

Fig. 4 is the figure that is illustrated in the concentration and the burn rate relation of polymerization atarting material in the first embodiment of the invention.

Fig. 5 is the performance plot that the relation of the frequency of alternating voltage and burn rate is shown.

Fig. 6 is the sectional view of primary structure that the liquid crystal indicator of second embodiment of the invention is shown.

Fig. 7 is the planimetric map that the part of the pixel electrode that forms trickle slit is shown, and this slit forms orientation maps shape.

Fig. 8 is the sectional view of the appearance when liquid crystal layer formation is shown.

Fig. 9 is the synoptic diagram that the definition of surface average roughness is shown.

Figure 10 is the microphotograph (AFM picture) that is illustrated in the appearance of the condensate structure on the apertured pixel electrode of TFT substrate-side.

Figure 11 is the performance plot that the relation of the mean roughness on condensate structure surface and burn rate is shown.

Embodiment

(first embodiment)

Describe with Fig. 1～4 pair Liquid crystal disply device and its preparation method according to first embodiment of the invention.At first, use the Liquid crystal disply device and its preparation method of Fig. 1 diagrammatic illustration present embodiment.Figure 1 shows that the state of a pixel 2 of liquid crystal indicator in the being seen present embodiment of real estate normal direction.In the rectangle field of grid bus 4 and 6 delimitations of drain electrode bus, form pixel 2 by dielectric film (not shown).The upper left side of pixel 2 forms TFT16 in the drawings, and this TFT16 has conduct applies the switching device when increasing and decreasing voltage on pixel electrode described later function.Form criss- cross connection electrode 12,14 in pixel 2, it is identical rectangular four orientation area that this connection electrode is partitioned into periphery.The basic centre that connection electrode 12 is formed on pixel 2 is parallel with drain electrode bus 6, and connection electrode 14 forms on the cumulative capacity bus 18 of crossing pixel 2 central authorities substantially.

Be concatenated to form a plurality of strip shaped electric poles 8 that are the micro-electrode figure of miter angle with connection electrode 12,14 substantially. Connection electrode 12,14 and a plurality of strip shaped electric poles 8 constitute pixel electrode.Upper left strip shaped electric poles 8 is electrically connected with the source electrode of TFT16 among the figure.The space 10 of electrode state is removed in 8 formation of the strip shaped electric poles of adjacency.Strip shaped electric poles 8 and space 10 constitute the orientation limitations structure.Certainly, replace strip shaped electric poles 8 and the space 10 of Fig. 1, also form fine wire projection on the pixel electrode that can in pixel 2, comprehensively form.Though omitted diagram, can certainly be corresponding with the structure that the orientation limitations that forms in pixel electrode one side is used, on opposing substrates, form insulativity structure or slit (part of public electrode is carried out composition and the part of removing).

After forming this trickle line and space diagram on the pixel electrode of the pixel 2 of TFT substrate, on the opposite face of TFT substrate and relative substrate, form vertical alignment layer.Can for example can adopt the alignment films of acid amides acid type with the material of multiple material as vertical alignment layer.

Secondly, the negative type liquid crystal that sealing has negative electricity capacity rate anisotropic properties, bonding these two substrates.Sneak into the polymerism composition with the regulation ratio in the negative type liquid crystal.The polymerism composition adopts diacrylate monomer.

Figure 2 shows that on the liquid crystal layer of LCD plate while the operation that applies the voltage irradiation ultraviolet radiation.As shown in Figure 2, be placed with the LCD plate in the exposure cell of ultraviolet lamp 32.Make before the monomer polymerization in the LCD plate, make being oriented to of liquid crystal molecule in the liquid-crystal composition be basically perpendicular to real estate.Secondly, apply voltage by 34,36 at the electrode of voltage bringing device 30 between two substrates that are located at the LCD plate.Like this, be applied in voltage on the liquid crystal layer 38 of 34,36 sealings of electrode, the liquid crystal molecule in the pixel 2 just tilts to prescribed direction.When voltage bringing device 30 was continuously applied voltage, the high-pressure mercury-vapor lamp of ultraviolet lamp 32 (not shown) was to LCD plate face irradiating ultraviolet light (UV light).Like this, ultraviolet light is irradiated onto on the liquid crystal material that has added monomer, the direction of orientation of the liquid crystal molecule when monomer polymerization and condensateization, regulation drive usually.

Figure 3 shows that the state of the pixel 2 of the MVA-LCD that is seen along the real estate normal direction with other structures.Formation shown in Figure 3 has following characteristics: the pixel electrode 3 of TFT substrate-side that will form TFT16 is as line and space diagram.As shown in Figure 3, pixel electrode 3 has strip shaped electric poles 8 and the space 10 with drain electrode bus 6 parallel formation lines and space diagram (1ine and space pattern).

Each strip shaped electric poles 8 is by being electrically connected with the connection electrode 14 of grid bus 4 parallel formation in pixel 2 basic centre.And, the part of strip shaped electric poles 8 be connected with the source electrode 22 of the drain electrode 20 relative configurations of TFT16.

With the relative position of the connection electrode 14 of the pixel region central portion of relative substrate (not shown) on form the wire projection that extends in parallel with grid bus 4.By this wire projection, can more clearly determine the orientation limitations direction of liquid crystal molecule.

Identical with structure shown in Figure 2, on liquid crystal layer (not shown), apply voltage, make liquid crystal molecules tilt in the pixel 2 to prescribed direction, under this state, by irradiating ultraviolet light polymerization single polymerization monomer on the liquid crystal material that has added monomer, realize the tilt angle of liquid crystal molecule and/or stablizing of direction of orientation.

For the burn phenomenon of the image that produces owing to the method for the direction of orientation that adopts the liquid crystal molecule when using the condensate regulation to drive among the LCD of the manufacture method manufacturing that reduces above explanation, and various monomers, polymerization atarting material and liquid-crystal composition (liquid crystal molecule) are studied.Its result shows that the polymerization atarting material is reducing best ultraviolet irradiation amount effectively, when enhancing productivity, can cause image burn.Among the LCD of the liquid crystal molecular orientation direction when using the polymkeric substance regulation to apply voltage, when though the concentration of the polymerization atarting material of the monomer polymerization when helping to cause the ultraviolet ray irradiation is high, the time that polymerization needs is short, but the burn phenomenon of the LCD display image of finishing can worsen relatively.If fully add the polymerization atarting material in liquid crystal material, then the time of polymerization needs will be elongated, and the burn phenomenon degree of the display image of the LCD that finishes simultaneously can alleviate relatively.Therefore, in order to improve the burn phenomenon, should reduce the concentration of polymerization atarting material.

That is,, perhaps after only adding a spot of polymerization atarting material in advance, monomer is carried out polymerization, can alleviate the burn phenomenon of image by in liquid crystal material, not adding the polymerization atarting material of monomer.

Concentration in the liquid crystal material of polymerization atarting material before polymerization is x (wt%, below identical), the concentration in the liquid crystal material of monomer before polymerization be concentration in y, the liquid-crystal composition liquid crystal material before polymerization be z, when the burn rate is α, the concentration x of polymerization atarting material is 0≤x≤0.002 (wt%) preferably.Especially the burn rate α when x=0 is minimum.And, consider that from the aspect of burn rate the concentration y of monomer is preferably below the above 10wt% of 0.1wt%.

Following the obtaining of burn rate α.The long-time figure that shows the black and white grid in the viewing area of LCD.Afterwards, make whole demonstration field show the medium tone of regulation, (β-γ) is with this luminance difference (β-γ) divided by the brightness γ in black display field, obtain the burn rate to obtain brightness γ poor in the brightness β in white demonstration field and black display field.

That is burn rate α=((β-γ)/γ) * 100 (%),

Figure 4 shows that the concentration of polymerization atarting material and the relation of burn rate.Transverse axis is represented the concentration (wt%) of polymerization atarting material among Fig. 4, and the longitudinal axis is represented burn rate (%).As mentioned above, preferably below 0.002wt%, the burn rate α when not adding polymerization initiator in liquid crystal material fully is minimum for the concentration of polymerization atarting material.The person it seems from overview, and the burn rate α of LCD is if about 5%～6%, and is then no problem in practical application, if the 10% burn phenomenon that can notice image.From as shown in Figure 4 figure as seen, if the concentration of polymerization atarting material below 0.002wt%, then the burn rate can obtain characteristic no problem in the practical application below 6%.Polymerization atarting material concentration is 0%, that is, available burn rate is extremely not low when not using the polymerization atarting material, is 3%.

With following specific embodiment and Comparative Examples, the Liquid crystal disply device and its preparation method according to present embodiment is described.In each embodiment and Comparative Examples of present embodiment, use MVA-LCA with structure shown in Figure 1.That is, form vertical alignment layer, liquid crystal has negative electricity capacity rate anisotropic properties.And relative two Polarizers clamping two substrates are configured on intersection Nicol (cross nicol) prism, are to be the normal black pattern (normally black mode) that black shows when not applying voltage.And, the polarizing axis of Polarizer (not shown) or the direction that intersect vertically substantially parallel towards relative each bus.Board size is that diagonal line is 15 inches, and resolution is XGA.

(embodiment 1)

Be about the molecular weight that mixes 0.3wt% in 350 the liquid-crystal composition at mean molecular weight and be about 350 photo-curable diacrylate monomer, the liquid crystal material of the polymerization atarting material of 0.006wt% has been sneaked in sealing between substrate.Then, be recorded in to liquid crystal layer and apply under the state of voltage the direction of lqiuid crystal molecule tipping behind the polymerization single polymerization monomer.The ultraviolet ray of monomer polymerization is shone in room temperature (20 ℃), and irradiation energy is 10J/cm ²(use the ultraviolet lamp identical, shine) with 10 times of the ultraviolet irradiation time in the Comparative Examples 1 with the Comparative Examples 1 of postscript.For the MVA-LCD that finishes, show the black and white checker pattern after 48 hours, the burn rate α that measures is 15%.

(embodiment 2)

Be about the molecular weight that mixes 0.3wt% in 350 the liquid-crystal composition at mean molecular weight and be about 350 photo-curable diacrylate monomer, sealing does not have the liquid crystal material of mixed polymerization atarting material fully between substrate.Then, be recorded in to liquid crystal layer and apply under the state of voltage the direction of lqiuid crystal molecule tipping behind the monomer polymerization.The ultraviolet ray of monomer polymerization is shone in room temperature (20 ℃), and irradiation energy is 100J/cm ²(use the ultraviolet lamp identical, with 100 times of times of the ultraviolet irradiation time in the Comparative Examples 1 shine) with the Comparative Examples 1 of postscript.For the MVA-LCD that finishes, show the black and white checker pattern after 48 hours, the burn rate α that measures is 3%.

(Comparative Examples 1)

Be about the molecular weight that mixes 0.3wt% in 350 the liquid-crystal composition at mean molecular weight and be about 350 photo-hardening diacrylate monomer, the liquid crystal material of the polymerization atarting material of 0.008wt% has been sneaked in sealing between substrate.Then, be recorded in to liquid crystal layer and apply under the state of voltage the direction of lqiuid crystal molecule tipping behind the monomer polymerization.The ultraviolet ray of monomer polymerization is in room temperature (20 ℃) irradiation down, and irradiation energy is 1J/cm ²For the MVA-LCD that finishes, show the black and white checker pattern after 48 hours, the burn rate α that measures is 35%.

No matter under any condition, ultraviolet postradiation LCD plate all can obtain the optical characteristics that equates substantially.Shown in embodiment 1,2 and Comparative Examples 1,, then can significantly alleviate the burn phenomenon of the display image of the LCD that finishes if reduce the concentration of polymerization atarting material or do not add the polymerization atarting material fully.

(second embodiment)

(bare bones)

At first the bare bones to second embodiment of the present invention describes.

The inventor as adopt improvement MVA-LCD, improve numerical aperture increase brightness, in the gimmick of also improving the standard aspect the cost, developed following orientation limitations technology: by in liquid crystal, sneaking into the monomer of photopolymerization or thermal polymerization, make monomer polymerization when between substrate, applying assigned voltage, can obtain stable orientations.

But, in above-mentioned orientation limitations technology, even the known plate that does not adopt by the mode of curing such as monomer material also can produce the problem of the degree deterioration of the liquid crystal board burn when driving.

If with the above-mentioned identical burn rate α that obtains of first embodiment is 5～6%, then there is not the problem in the practical application, if but burn rate α reaches 10%, and then the user can notice the phenomenon of image burn, and very important.

Usually in the driving of liquid crystal indicator, on liquid crystal layer, apply alternating voltage in order to prevent burn.But, because it is different with formed electrode to clamp the layer structure of a pair of substrate of liquid crystal layer, so can polarization between substrate and can exert an influence to alternating voltage.Consequently, even apply the alternating voltage of steady state value from the external voltage bringing device to liquid crystal indicator, the voltage that applies on liquid crystal layer also can occur two different values owing to the switching of alternating voltage.If the value of voltage changes, then the orientation of liquid crystal and state also change.

Therefore, if on liquid crystal layer, apply the alternating voltage of the frequency 30Hz of common driving usefulness, when keeping this to apply state, form the condensate structure of orientation control usefulness, then under the residual state of the orientation disorder that produces owing to the transient voltage variation, direction of orientation is stipulated.If the generation orientation disorder just can be seen the burn on liquid crystal indicator, display characteristic will reduce.

The inventor expects improving the frequency of the alternating voltage that applies in order to suppress burn on liquid crystal layer.

So, studied the frequency of alternating voltage and the relation of burn rate α, as shown in Figure 5, the minimum value of burn rate α was below 5% when the frequency of alternating voltage was 60Hz.If frequency further strengthens, burn rate α then slowly increases (1kHz and frequency 30Hz's is equal substantially), so the proper range of frequency is 60Hz～1kHz.

Burn rate α so change be because: if when the frequency that makes alternating voltage greater than common driving, for example is 2 times of (60Hz) left and right sides, the response speed of liquid crystal molecule just can't be caught up with the switch speed of alternating voltage.Therefore, the orientation of liquid crystal molecule is not according to alternating voltage, but the intermediateness regulation when switching by each.By form condensate under this state, the burn rate reduces and can not produce orientation disorder, can obtain the good liquid crystal indicator of display characteristic.

(embodiment)

Bare bones according to above-mentioned present embodiment describes specific embodiment.Here the liquid crystal indicator that has primary structure shown in Figure 6 is an object.

This liquid crystal indicator constitutes by the relative a pair of transparent glass substrate 41,42 that leaves predetermined distance with at the liquid crystal layer 38 of 41,42 clampings of this a pair of transparent glass substrate.Transparent glass substrate 41,42 is engaged fixing by encapsulant (not shown).

On transparent glass substrate (TFT substrate) 41 on one side, form the TFT (not shown) that forms by a plurality of pixel electrodes 3 (forming) and active component by insulation course 44 by ITO, also form the transparent vertical alignment layer 46a that covers pixel electrode 3.On the transparent glass substrate (substrate relatively) 42 of another side, stack gradually color filter (with black matrix (not shown)), public electrode (comparative electrode) 48 and vertical alignment layer 46b.Then, vertical alignment layer 46a, 46b are tightly against with clamping liquid crystal layer 38, and by encapsulant fixing glass substrate 41,42, the outside of each substrate 41,42 is provided with polariscope 49,50.Pixel electrode 3 forms with active matrix (TFT matrix), is the drain electrode bus 6 that is connected with the drain electrode of TFT shown in the illustrated embodiment.And, form the grid bus (not shown) that is connected with the grid of TFT.Electrode only is located on the substrate on one side.

Liquid crystal layer 38 is by forming from the liquid crystal injecting port injection liquid crystal that is located on the encapsulant.Sneak into the monomer of photopolymerization or thermal polymerization in the above-mentioned liquid crystal.As shown in Figure 7, form trickle slit 45 on pixel electrode 3, this slit 45 forms the orientation figure.Then, as shown in Figure 8, on the liquid crystal that has injected, apply the alternating voltage of regulation, apply the alternating voltage of 60Hz～1kHz in the present embodiment, implement UV rayed or thermal treatment simultaneously.The alternating voltage that applies for example is a square wave.Like this, make above-mentioned monomer polymerization, go up the condensate structure 13 that forms the orientation figure restriction that is subjected to slit 45 on the top layer (surface of vertical alignment layer 46a, 46b) of liquid crystal layer 38, liquid crystal molecule is copied above-mentioned orientation figure to be orientated by this condensate structure restriction.

What make in the reality in the present embodiment, is that pel spacing is that 297 μ m, pixel count are 1024 * 768 liquid crystal indicator.

Form pixel electrode, this electrode is gone up at substrate (TFT substrate) on one side and is formed TFT element, drain electrode bus, the trickle slit that grid bus and orientation limitations are used.Substrate (substrate relatively) at another side is gone up formation color filter and public electrode.Use the glass substrate OA-2 (NEG system) of thickness of slab 0.7mm in the baseplate material.(upper right, bottom right, upper left, sit down) extends to form from four orientation of pixel mediad in fine slit.The width in slit is 3 μ m, and the distance between the slit is 3 μ m.On these substrates, form vertical alignment layer (poly-imines material), under 180 ℃, carry out 60 minutes thermal treatment with print process.These substrates are the partition (Plot water Off ア イ Application ケ ミ カ ル System of 4 μ m by diameter) bonding, make dummy cell.In the unit that obtains like this, inject the liquid crystal that has added micro-photopolymerization monomer, make LCD panel with negative electricity capacity rate anisotropic properties.The addition of photopolymerization monomer is 0.3wt%.

Secondly, apply the alternating voltage (10V) of the frequency 60Hz of 2 times of common drivings onboard, irradiation UV light solidifies photopolymerization monomer under this state.The rayed amount is 4000mJ/cm approximately ²(wavelength 365nm).State of orientation in the pixel does not have disorder, shows that the burn rate α that the black and white checker pattern measured after 48 hours is 5%.

(Comparative Examples)

Comparative Examples to the foregoing description describes.This Comparative Examples is except following requirement, and is same as the previously described embodiments.

Making the voltage when solidifying photopolymerization monomer is the alternating voltage (10V) of common frequency 30Hz, irradiation UV light.

At this moment, different with the situation of the foregoing description, the state of orientation in the pixel produces some disorders, shows that the burn rate α that the black and white checker pattern measured after 48 hours is 10%.

As mentioned above, the manufacture method according to the liquid crystal indicator of present embodiment can not produce bad phenomenon such as burn in demonstration, can be simply and positively improve display characteristic, realize the demonstration of high reliability.

(the 3rd embodiment)

(bare bones)

Below, the bare bones of third embodiment of the invention is described.

The inventor as improvement MVA-LCD, improve numerical aperture increase brightness, in the gimmick of improving the standard aspect the cost, developed following orientation limitations technology: by in liquid crystal, sneaking into the monomer of photopolymerization or thermal polymerization, make monomer polymerization when between substrate, applying assigned voltage, form the condensate structure of orientation figure with this top layer (surface of alignment films), obtain the stable orientations of liquid crystal molecule by this condensate structure with regulation at liquid crystal layer.

But, in the above-mentioned orientation limitations technology,, aspect the burn of the liquid crystal board when driving, also have the abominable problem of degree even do not adopt the plate of the mode of solidifying by condensate structure etc.

If the burn rate α that obtains equally with above-mentioned first embodiment then can not produce the problem in the practical application 5～6%, if but burn rate α reaches 10%, and then the user then can notice the phenomenon of image burn, and very important.

The inventor has expected being controlled to be less for the mean roughness that suppresses to burn condensate structure surface.

Investigation result about the relation of the surface average roughness of condensate structure and burn rate α is as follows.

Here, the liquid crystal that adopts vertical alignment layer and have negative electricity capacity rate anisotropic properties will intersect Nicol prism as Polarizer and stick on the LCD panel both sides, be made as and often deceive pattern.Can select any Photoepolymerizationinitiater initiater in mono acrylic ester, diacrylate, the triacrylate for use as the kind of polymerizable monomer, be 0.3wt% with the polymerizable monomer of 0.01wt% and total melting concn of Photoepolymerizationinitiater initiater.The condensate condition is to be 4～10J/cm with UV light and exposure ²

Change the combination of above-mentioned polymerizable monomer and Photoepolymerizationinitiater initiater, mix, inject liquid crystal indicator with liquid crystal.Afterwards, on liquid crystal, apply voltage adjustment orientation, make its condensateization simultaneously, the evaluation of the rate of burning.Afterwards, decomposed solution crystal device, the surface of the condensate structure that observe to form by atomic force microscope (AFM), the relation of investigation mean roughness and burn rate α.

Here, mean roughness (Ra) is meant: extract standard length out along this average line direction from roughness curve, direction with this extraction average line is an X-axis, the direction of vertical multiplying power is a Y-axis, when roughness curve with y=f (x) when expression, the value of obtaining by following formula and Fig. 9 (based on JIS80601 1994 " the average thick さ Yi in surface Ding Righteousness and び represent ").

[several 1]

$\mathrm{Ra}=1/L{\&Integral;}_0^L\left|f\left(x\right)\right|\mathrm{dx}$ L: standard length

Figure 10 shows that a side at the TFT substrate has the AFM picture (the lip-deep concavo-convex condensate structure that is equivalent to) of the condensate structure on the pixel electrode in slit, Figure 11 shows that based on the surfaceness of the condensate structure of this AFM picture and the relation of burn rate.

As shown in figure 11, surperficial average roughness rate is more little, and α is also more little for the burn rate, thereby as can be known: be located at below the 10nm by the roughness with the surface, satisfy the allowed band of burn rate α, then burn characteristics is suppressed in the below horizontal of the problem that do not have in the practical application.Therefore, the mean roughness on surface that makes polymeric films can obtain the good liquid crystal indicator of display characteristic below 10nm.

Further the result of the combination of the exposure of the concentration of the concentration of discussion polymerizable monomer, Photoepolymerizationinitiater initiater and UV light is, confirms that burn rate α can be suppressed in below 6%.

(embodiment)

Bare bones based on above-mentioned present embodiment describes specific embodiment with reference to Fig. 6 to Fig. 8.Here be object with liquid crystal indicator with primary structure as shown in Figure 6.Because the structure of TFT substrate and relative substrate is identical with the specific embodiment of the second above-mentioned embodiment, so omit its explanation.

Liquid crystal layer 38 is by forming from the liquid crystal injecting port injection liquid crystal that is located on the encapsulant.Sneaked into the monomer of photopolymerization or thermal polymerization in the above-mentioned liquid crystal.As shown in Figure 7, also form trickle slit 45 on pixel electrode 3, this slit 45 forms the orientation figure.Then, as shown in Figure 8, by implementing rayed or thermal treatment in the alternating voltage that on the liquid crystal that has injected, applies regulation, above-mentioned monomer polymerization is gone up the condensate structure 13 that forms the orientation figure restriction that is subjected to slit 45 on the top layer (surface of vertical alignment layer 46a, 46b) of liquid crystal layer 38, liquid crystal molecule is subjected to the restriction of condensate structure, copies above-mentioned orientation figure orientation.As mentioned above, the surface average roughness of condensate structure 13 is controlled at below the 10nm in the present embodiment.

What make in the reality in the present embodiment, is that pel spacing is that 297 μ m, pixel count are 1024 * 768 liquid crystal indicator.

Go up at substrate (TFT substrate) on one side and to form the trickle slit that TFT element, drain electrode bus, grid bus and orientation limitations use and the pixel electrode that forms.Substrate (substrate relatively) at another side is gone up formation color filter and public electrode.Use the glass substrate OA-2 (NEG system) of thickness of slab 0.7mm in the baseplate material.On these substrates, form vertical alignment layer (poly-imines material), under 180 ℃, carry out 60 minutes thermal treatment with print process.Is these substrates the partition (Plot water Off ア イ Application ケ ミ カ ル System of 4 μ m by diameter) bonding, make dummy cell.Like this, the mean molecular weight that mixes 0.3wt% is 350 optical polymerism diacrylate monomer and the DAROCUR1173 as Photoepolymerizationinitiater initiater (チ バ ス ベ シ ヤ Le テ イ ケ ミ カ Le ズ Zhu formula Hui She System) of 0.01wt%, injects in this dummy cell.Afterwards, by in the voltage that on liquid crystal layer, applies DC5V with 4J/cm ²Exposure irradiation UV light, form the condensate structure of liquid crystal aligning control usefulness.At this moment, the surface average roughness of condensate structure is 6nm.

As mentioned above, utilize the manufacture method of the liquid crystal indicator of present embodiment, can in demonstration, not produce bad phenomenon such as burn, simple and easy and positively improve display characteristic, realize the demonstration of high reliability.

The present invention is not limited only to above-mentioned embodiment, also various distortion can be arranged.

For example, though adopt diacrylate as monomer in the above-described embodiment, the present invention is not limited only to this, for example can certainly be with multi-functional polymeric triacrylate as the polymerism composition.

And, though in the above-described embodiment, making the polymerism composition that adopts polymeric liquid crystal aligning stabilization as being used to, is that example is illustrated with the monomer, but the present invention is not limited only to this, can certainly use the potpourri of oligomer and oligomer and monomer as the polymerism composition.

As mentioned above, the present invention has improved the image burn phenomenon that method produced of the direction of orientation of the liquid crystal molecule when utilizing the condensate regulation to drive, and is simple and easy and positively improve display characteristic, realizes the demonstration of high reliability.

Claims (6)

1. A liquid crystal display device, the device is relatively configured with a first substrate with a first electrode and a second substrate with a second electrode through an orientation film and a liquid crystal layer, the device is characterized in that, The above-mentioned liquid crystal layer forms a polymer structure that aligns the liquid crystal molecules in a predetermined direction in the liquid crystal, The average surface roughness of the above-mentioned polymer structure is 10 nm or less. 2. The liquid crystal display device according to claim 1, wherein a slit for restricting the alignment pattern is formed on the first electrode. 3. The liquid crystal display device according to claim 1 or 2, wherein the polymer structure is formed by polymerizing monomers mixed in the liquid crystal by light irradiation or heat treatment. 4. A method for manufacturing a liquid crystal display device, the liquid crystal display device is formed by relatively disposing a first substrate provided with a first electrode and a second substrate provided with a second electrode through an alignment film and a liquid crystal layer, the method features is that In the state where the above-mentioned liquid crystal layer composed of liquid crystal mixed with monomers for aligning liquid crystal molecules in a predetermined direction is sandwiched between the above-mentioned first substrate and the second substrate, while applying a voltage between the above-mentioned substrates, the above-mentioned monomer Polymerization to form a polymer structure with a specified orientation pattern, when the orientation of liquid crystal molecules is restricted by the above polymer structure, The average surface roughness of the polymer structure is controlled below 10 nm. 5. The method of manufacturing a liquid crystal display device according to claim 4, wherein a slit for restricting the alignment pattern is formed on the first electrode. 6. The method for manufacturing a liquid crystal display device according to claim 4 or 5, wherein the monomer is polymerized by light irradiation or heat treatment to form the polymer structure.

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