CN102147547B - Liquid crystal display cells - Google Patents

Abstract

There is provided a kind of liquid crystal display cells, have: first substrate, it has the first electrode, has been carried out orientation process in a first direction, second substrate, itself and first substrate are oppositely disposed abreast, have the second electrode, have been carried out orientation process in a second direction, and liquid crystal layer, it is configured between first substrate and second substrate, comprise chiral material, carry out twisted-oriented, second direction is the normal direction from first substrate side, on the first gyratory directions, the direction of 70 ° ~ 110 ° is become relative to first direction, the liquid crystal molecule of liquid crystal layer is along the first gyratory directions twisted arrangement, from the normal direction of first substrate side, chiral material gives the turning quality towards second gyratory directions contrary with the first gyratory directions along the liquid crystal molecule from first substrate towards the direction of second substrate to liquid crystal layer, first substrate and second substrate are oriented to be processed into manifest and are greater than 0 ° and the pretilt theta being less than or equal to 5 °, when setting the thickness of liquid crystal layer as d, when the chirality spacing of chiral material is p, θ, d and p meets following formula (1) and (2), <maths num=" 0001 " > </maths>

Description

Liquid crystal display cells

Technical field

The present invention relates to liquid crystal display cells.

Background technology

Disclose the twisted-nematic (twistednematic with good display comparison degree and broad effective angular field of view; TN) invention (such as with reference to patent documentation 1) of type liquid crystal display cells.The liquid crystal display cells recorded in patent documentation 1 has such feature: with by the combination in the direction of orientation process that applies on a pair transparent electrode substrate clamping liquid crystal layer the contrary direction (the second gyratory directions) of the gyratory directions (the first gyratory directions) of liquid crystal molecule that limits makes liquid crystal molecule twisted arrangement, and carry out the orientation process of a pair transparent electrode substrate, make mutually different from the tilt angle of the liquid crystal molecule that each transparent electrode substrate connects

In the liquid crystal display cells that patent documentation 1 is recorded, achieve the raising of electro-optical characteristic, even if when the revolution (distortion) about the first gyratory directions is set as the scope of 91 ~ 100 °, by the effect of inverse twisted arrangement, the electro-optical characteristic same with the TN type liquid crystal display cells by 90 ° of rubbing manipulations also can be obtained.In addition, because make mutually different from the tilt angle of the liquid crystal molecule that substrate connects, so the incomplete generation to mistake caused of orientation due to each liquid crystal molecule can be prevented, good display level can be obtained.

In the nematic liquid crystal layer that with the addition of chirality (chiral) material, disclose the invention (such as with reference to patent documentation 2) that the torsional direction of less than 90 ° that brought out by alignment films and the torsional direction of liquid crystal material become rightabout liquid-crystal apparatus.The liquid-crystal apparatus of this structure can reduce driving voltage.

Be known to the invention (such as with reference to patent documentation 3) that significantly can reduce the liquid crystal cell of driving voltage.As the liquid crystal cell recorded in the patent documentation 3 of one of the achievement in research of present inventors, become rightabout mode with the torsional direction of the liquid crystal material making the torsional direction of the liquid crystal material determined by the orientation process direction of one group of alignment films and the combination of tilt angle and brought out by chiral material and make.Be called inverse distortion (even distortion) structure by the ordered state of the liquid crystal molecule of the combination defined of orientation process direction and tilt angle, the ordered state of the liquid crystal molecule produced due to the influence power of chiral material is called splash distortion (spraytwist) structure.

Splash distorted-structure only not to be executed under alive state stable, and stablizes executing alive state subinverse distorted-structure.Therefore, can make to transfer to inverse distorted-structure from splash distorted-structure by applying voltage.Once after transferring to inverse distorted-structure, after stopping applies voltage during several minutes to several tens minutes, also stably can maintain inverse distorted-structure.Liquid crystal molecule can use under inverse twist structured state, uses low voltage drive.

But, the liquid crystal molecule that patent documentation 3 is recorded, sharpness (sharpness) (sharpness of change for executing alive transmittance) is identical or slightly excellent with common TN type liquid crystal display cells, there is when being applied to simple matrix and driving the problem being difficult to make the capacity of display become large.

There will be a known about the torsion angle of liquid crystal molecule is made larger than the torsion angle in TN type liquid crystal display cells, improve sharpness, be simple matrix drive but the supertwist that simultaneously can realize Large Copacity display to row (supertwistednematic; STN) invention (such as with reference to patent documentation 4) of type liquid crystal display cells.In the invention that patent documentation 4 is recorded, for tackling the painted problem caused by double refraction, disclosing compensating painted liquid crystal cells stacked, realizing the method for white and black displays.

If but using compensation unit, then the manufacturing cost of liquid crystal cells and the thickness of liquid crystal display cells and weight all will become about twice.

Although can replace compensating unit and use optical compensation films, optical compensation films is not cheap.Have again, when the display environment temperature variation of liquid crystal display cells, even if because the delay of the liquid crystal layer in driver element changes with this, the delay of optical compensation films also changes hardly, so optimum compensation can not be carried out, exist and painted or display comparison degree occurs reduce such problem.

In addition in the invention of patent documentation 4 record, also there is problem common in STN type liquid crystal display cells.The display performance of the liquid crystal display cells of STN type is high for the interdependence of the gap of liquid crystal cells or the change of tilt angle, easily due to small element thickness is irregular or the difference of tilt angle and occur show uneven.Therefore, the management of manufacture process is strict (manufacturing surplus little), and yield rate is low.In STN type liquid crystal display cells, need the high tilt angle of about 5 ~ 9 °, obtain uniform tilt angle also difficult, especially the management of friction process is important.

Further, the visual angle interdependence shown in STN type liquid crystal display cells is large, changes view directions minutely and display will be made to change, particularly there is the problem that when changing visual angle in the vertical direction, reversal displaying is such.In addition, STN type liquid crystal display cells, compared with TN type liquid crystal display cells, needs the response time.The response time of such as, TN type liquid crystal display cells under room temperature is about 30msec, and the response time of STN type liquid crystal display cells is about 200msec.

Patent documentation 1: Japanese Patent No. 2510150 publications

Patent documentation 2: Japanese Unexamined Patent Publication 2000-199903 publication

Patent documentation 3: Japanese Unexamined Patent Publication 2007-293278 publication

Patent documentation 4: Japanese Unexamined Patent Publication 03-111812 publication

Summary of the invention

The object of this invention is to provide the liquid crystal display cells with excellent sharpness.

According to the first viewpoint of the present invention, provide a kind of liquid crystal display cells, it has first substrate, and it has the first electrode, has been carried out orientation process in a first direction, second substrate, itself and above-mentioned first substrate are oppositely disposed abreast, have the second electrode, have been carried out orientation process in a second direction, and liquid crystal layer, it is configured between above-mentioned first substrate and above-mentioned second substrate, comprise chiral material, carry out twisted-oriented, above-mentioned second direction is the normal direction from above-mentioned first substrate side, on the first gyratory directions, the direction of 70 ° ~ 110 ° is become relative to above-mentioned first direction, the liquid crystal molecule of above-mentioned liquid crystal layer is along above-mentioned first gyratory directions twisted arrangement, from the normal direction of above-mentioned first substrate side, above-mentioned chiral material gives the turning quality towards second gyratory directions contrary with above-mentioned first gyratory directions along from above-mentioned first substrate towards the direction of above-mentioned second substrate to the liquid crystal molecule of above-mentioned liquid crystal layer, above-mentioned first substrate and above-mentioned second substrate are oriented to be processed into manifest and are greater than 0 ° and the pretilt theta being less than or equal to 5 °, when setting the thickness of above-mentioned liquid crystal layer as d, when the chirality spacing of above-mentioned chiral material is p, above-mentioned θ, above-mentioned d and above-mentioned p meets following formula (1) and (2),

$2\&le;\frac{p}{d}<4\&CenterDot;\&CenterDot;\&CenterDot;\left(1\right)$

According to the present invention, the liquid crystal display cells with excellent sharpness can be provided.

Accompanying drawing explanation

Fig. 1 is the process flow diagram of the manufacture method of the liquid crystal display cells representing the first embodiment.

Fig. 2 is the sectional view of the outline of the liquid crystal display cells representing the first embodiment.

Fig. 3 is the splash distorted-structure state of the liquid crystal display cells representing the first embodiment and the photo of inverse distorted-structure state.

Fig. 4 (A) and (B) are the charts of the electro-optical characteristic of the liquid crystal display cells representing the first embodiment.

Fig. 5 is the chart of the electro-optical characteristic under the inverse aligned twisted state of the liquid crystal display cells representing the second embodiment.

Fig. 6 is the chart of the electro-optical characteristic under the inverse aligned twisted state of the liquid crystal display cells representing the 3rd embodiment.

Fig. 7 represents that tilt angle gets the chart of the electro-optical characteristic under the inverse aligned twisted state of the liquid crystal display cells of 21 °.

Fig. 8 is the chart of the relation of the mixing ratio representing two kinds of polyimide materials and the tilt angle manifested.

Fig. 9 is the chart of the relation of applying voltage under the inverse aligned twisted state of the liquid crystal display cells representing the 4th embodiment and transmittance.

Figure 10 (A) to (C) is the chart of the relation of applying voltage under the inverse aligned twisted state of the liquid crystal display cells representing the first ~ three comparative example and transmittance respectively.

Figure 11 is the boundary voltage of the liquid crystal display cells gathering expression the first ~ four embodiment and the table of the physics value of liquid crystal material that uses in each liquid crystal display cells.

Figure 12 is the figure of an example of the waveform representing the driving voltage applied between upside ITO electrode 12a, downside ITO electrode 12b by power supply 20.

Figure 13 (A) and (B) represent the chart manifesting the example of the pretilt theta of excellent sharpness and the scope of p/d in inverse TN type liquid crystal display cells.

Label declaration

10a upper board

10b lower board

Glass substrate on the upside of 11a

Glass substrate on the downside of 11b

ITO electrode on the upside of 12a

ITO electrode on the downside of 12b

13a upside orientation film

Alignment films on the downside of 13b

14 liquid crystal layers

14a liquid crystal molecule

Polaroid on the upside of 15a

15b lower-side polarizing plate

20 power supplys

Embodiment

The liquid crystal display cells recorded in patent documentation 3 is called inverse TN type liquid crystal display cells below, it has a kind of liquid crystal layer, the torsional direction that this liquid crystal layer is made into the liquid crystal material making the torsional direction of the liquid crystal material determined by the orientation process direction of one group of alignment films and the combination of tilt angle and lured by optically active substance (chiral material) becomes rightabout mode, by applying voltage (electric field treatment) to liquid crystal layer, inverse distortion (even distortion) structure and splash distorted-structure switchably can be realized.

Against TN type liquid crystal display cells because the threshold value of driving voltage can be reduced, so have the feature that can realize low-power consumption and drive.Present inventor, for the purpose of the threshold value reducing driving voltage, studies for the inverse TN type liquid crystal display cells made under various conditions, and its achievement is open in patent documentation 3.Found that of the research of present inventors, tilt angle is higher then more stable against distorted-structure state, and the threshold value of the shorter then driving voltage of the chirality spacing of chiral material is lower, but inverse distorted-structure state is more unstable.

In patent documentation 3, describe by the achievement against distorted-structure state being the research carried out centered by stable, high tilt angle condition.Although also implement experiment about low tilt angle condition, but because inverse distorted-structure state is unstable ordered state originally, so for making the more unstable short spacing condition (chirality spacing is less than 20 μm) of inverse distorted-structure state be studied.

The invention of the application be about outside low tilt angle and the such usual research object of short spacing condition, the achievement in research of inverse distorted-structure state very under non-steady state.Under the condition that this is special, present inventors have found that the sharpness of liquid crystal display cells becomes the phenomenon be not expected to very sharply.Why such phenomenon can occur, and does not still understand now.In addition, even if by simulation, the generation of such phenomenon is also unpredictable.

The invention of the application is described according to embodiment below.

Fig. 1 is the process flow diagram of the manufacture method of the liquid crystal display cells representing the first embodiment.

Prepare the transparency carrier that two are formed with nesa coating such as ITO (indiumtinoxide) film.Transparency carrier is such as formed with the soda-lime glass that thickness is 0.7mmt.The thickness of ito film is such as 1500A.The cleaning of these transparency carriers, dry (step S101), use photo-mask process to carry out the graphical of ito film, transparency carrier (glass substrate) is formed transparency electrode (ITO electrode) (step S102).The etching of ITO electrode figure is such as carried out the wet etching of ferric trichloride as the etching solution of major component to use.

Be coated with aligning film material on the glass substrate to cover ITO electrode (step S103).The coating of aligning film material such as uses soft version (flexo) printing to carry out.Also ink jet printing can be used.As aligning film material, such as, use the SE-130 of (share) Nissan Chemical.SE-130 manifests the TN type of low tilt angle horizontal alignment membrane material used for liquid crystal display element.Aligning film material is not limited thereto.

The glass substrate being coated with aligning film material is placed on hot plate, at 100 DEG C, carries out vacation sintering (preliminary drying) (step S104) of 3 minutes.Thereafter, in clean stove, at 200 DEG C, carry out the true sintering (step S105) of 1 hour.Such alignment films (step S103 ~ S105) forming covering ITO electrode.

Then carry out friction treatment (orientation process) (step S106).Friction treatment makes volume have the roller high-speed rotary of the cylindrical shape of cloth then the operation rubbed in alignment films, can make thus to arrange in one direction (orientation) with the liquid crystal molecule of substrate contacts.

For keeping the thickness (substrate pitch from) of liquid crystal cells constant, dry type scattering method is used to scatter gap control material (step S107) on a glass substrate face.Gap control material uses the silicon based material ((share) Yu Bu East changes into Ha イ プ レ シ カ UF processed) of particle diameter 5 μm.Also baton round can be used.

Printing and sealing material on another glass substrate face, forms main seal patterns (step S108).Such as with the ES-7500 of silk screen print method printing as (share) Mitsui Chemicals of thermosetting encapsulant.ES-7500 comprises the glass fibre of the particle diameter 5 μm of a few percent.In addition divider also can be used to be coated with encapsulant.In addition, also can use and not be thermosetting but the material of photo-hardening or photo-thermal with the encapsulant of constrictive type.

On the real estate defining main seal patterns, include the conductive material of the baton round (Au ball) having implemented golden plating etc. in the printing of the position of regulation, form conductive material figure.Such as, the material of Au ball of the particle diameter about 6 μm comprising a few percent in ES-7500 is carried out serigraphy as conductive material.The printing of conductive material figure also can be carried out on the substrate different from the substrate being printed with main seal patterns.

Bonding glass substrate (step S109).A unit is made in the position coincidence that two glass substrates are specifying, implements thermal treatment in the pressurized state and make sealing material curing.The arrangement of the liquid crystal molecule here when making two glass substrates overlap, from upper board normal direction, makes right direction reverse 90 ° and combines like that.Such as use pressure sintering, sinter at 150 DEG C, carry out the thermmohardening of encapsulant.Thereafter, use chalker to form scar on the glass substrate, disconnect along the part forming scar, form rectangle.

Using the rectangular dummy cell after segmentation as unit, such as, in dummy cell, inject nematic liquid crystal (step S110) with vacuum impregnation.In liquid crystal material, such as, use the RDP-84910 of (share) DIC.Chiral material is added in liquid crystal.Adjustment addition, makes chirality spacing along becoming 15 μm from upper board towards the direction of lower board in left handed twist direction.

Such as using end encapsulant encapsulated liquid crystals mouth (step S111) of ultraviolet (UV) hardening type, for arranging the orientation of liquid crystal molecule, unit being heated to more than the phase inversion temperature of liquid crystal (step S112).At 120 DEG C, the thermal treatment of 30 minutes is such as carried out by stove.Thereafter, disconnect along the remainder using chalker to form scar on the glass substrate, cut into little other unit.

Chamfering (step S113) and cleaning (step S114) is implemented for cutting into little unit.In matting, by the cleaning unit such as clean-out system, organic solvent, wash the powder when liquid crystal and chamfering that adhere on unit off.

Finally, the face of the liquid crystal side opposition side with two glass substrates is pasted the polaroid (step S115) cutting into prescribed level.Two polaroids are configured to intersect Niccol, realize the TN type liquid crystal display cells of standard white, between the ITO electrode of two substrates, connect power supply.

Fig. 2 is the sectional view of the outline of the liquid crystal display cells representing the first embodiment.

The liquid crystal display cells of the first embodiment comprises the upper board 10a, the lower board 10b that are oppositely disposed in parallel to each other and the twisted nematic liquid crystal layer 14 clamped between two substrates 10a, 10b and forms.

Upper board 10a comprises upside glass substrate 11a, the upside ITO electrode 12a formed on the glass substrate 11a of upside and the upside orientation film 13a formed on the ITO electrode 12a of upside.Equally, lower board 10b comprises downside glass substrate 11b, the downside ITO electrode 12b formed on the glass substrate 11b of downside and the downside alignment films 13b formed on the ITO electrode 12b of downside.

Liquid crystal layer 14 configures between the upside orientation film 13a and the downside alignment films 13b of lower board 10b of upper board 10a.The thickness of liquid crystal layer 14 is such as 5 μm.

Upside and downside alignment films 13a, 13b are implemented the orientation process by friction.The orientation process direction of upside orientation film 13a and downside alignment films 13b is mutually orthogonal.When the frictional direction supposing upside orientation film 13a be first direction, the frictional direction of downside alignment films 13b be second direction time, second direction from the normal direction of upper board 10a, for taking first direction as the direction in 90 ° of benchmark.When liquid crystal material formation does not comprise the even distortion of splash structure, more specifically, such as when the intermembranous configuration of respective orientation does not comprise the liquid crystal material of chiral material, using determine in the direction by the friction treatment in upper board, the combination in the direction (direction that liquid crystal molecule erects substrate) that forms tilt angle and the direction of the tilt angle of lower board is as becoming the even twist structured combination reversing 90 ° in right direction.In addition, the tilt angle given to upside and downside alignment films 13a, 13b is 1 °.

Chiral material is added in liquid crystal layer 14.Addition is adjusted to and makes chirality spacing become 15 μm.From the normal direction of upper board 10a, the splash distorted-structure be arranged as along reversing in left handed twist direction from upper board 10a towards the direction of lower board 10b of the liquid crystal molecule 14a produced due to the influence power of chiral material.

The torsional direction of the liquid crystal molecule 14a under liquid crystal cells completion status is the left handed twist (splash distorted-structure) identical with the torsional direction caused by chiral material.

Power supply 20 is connected between upside ITO electrode 12a, downside ITO electrode 12b.Between two electrode 12a, 12b, applied the alternating voltage of more than threshold voltage by power supply 20, the arrangement of liquid crystal molecule 14a can be made thus from splash distorted-structure change (transfer) to even distortion (inverse distortion) structure.In addition, power supply 20 can be used to drive liquid crystal display cells.

Upper board 10a, lower board 10b with on the face of liquid crystal layer 14 opposition side, upside polaroid 15a, lower-side polarizing plate 15b are set respectively.Two polaroid 15a, 15b intersect Niccol and light transmission shaft and upside and lower board 10a, mode that the frictional direction of 10b is parallel configure to become.Therefore the liquid crystal display cells of this embodiment becomes the liquid crystal display cells of standard white type.

Fig. 3 is the splash distorted-structure state of the liquid crystal display cells representing the first embodiment and the photo of inverse distorted-structure state.Photo is taken from the normal direction of the upper board 10a of the liquid crystal display cells of the first embodiment.

As above-mentioned, the liquid crystal display cells of the first embodiment, by applying the alternating voltage of more than threshold voltage between upside ITO electrode 12a, downside ITO electrode 12b, can make the ordered state of liquid crystal molecule 14a transfer to inverse distorted-structure from splash distorted-structure.Frequency this transfer higher of the voltage applied occurs faster.

The threshold voltage value that transfer is occurred depends on the kind of liquid crystal material and the addition etc. of chiral material, but in the liquid crystal display cells of the first embodiment, by the voltage of more than 7V is applied about 3 seconds, the ordered state of a part of liquid crystal molecule 14a on electrode 12a, 12b transfers to inverse distorted-structure.In addition, the voltage of 10V, 200Hz is applied 3 minutes, the structure of all liquid crystal molecule 14a on result electrode 12a, 12b transfers to inverse distorted-structure.In addition, experiment described later is the experiment carried out after making structure transfer to inverse distorted-structure completely.

As shown in Figure 3, visually see up between splash aligned twisted state and inverse aligned twisted state and there is no large difference.In addition, white display good equally can both be carried out under any one ordered state.Although the torsional direction of the liquid crystal molecule of two ordered states is different, is all twisted nematic orientation, when from almost as broad as long when the observation unit of substrate normal direction.Such as observing liquid crystal cells from oblique direction, when applying the voltage slightly higher than the threshold voltage making generation shift, can easily distinguish two ordered states.This is the cause of direction (the best is depending on seeing direction) phase mutual deviation 90 ° that erects of liquid crystal molecule near the central authorities of the thickness direction of liquid crystal cells.

When applying the voltage of saturation voltage degree between two electrode 12a, 12b of the liquid crystal display cells of the first embodiment, under splash aligned twisted state and inverse aligned twisted state two states, liquid crystal molecule 14a erects on the direction vertical with substrate 10a, 10b, can obtain good black display.In addition, in each structure of two kinds of structures, when changing view and showing in vain with black display, both almost do not have reversal displaying, have wider viewing angle characteristic, this point can confirm.In addition, when comparing with splash distorted-structure, inverse twist structured visual angle is narrower slightly, but does not see large difference.

According to above-mentioned, the liquid crystal display cells of known first embodiment, under splash distorted-structure and inverse twist structured any one state, does not all carry out special optical compensation, can obtain good white black display.In addition, this point be not limited to the first embodiment, about other embodiment too.

The liquid crystal display cells of the first embodiment transferring to inverse aligned twisted state is placed not executing under alive state, observes the situation slowly turning back to splash aligned twisted from inverse aligned twisted.It can thus be appreciated that the liquid crystal display cells of the first embodiment is not being executed under alive state, splash aligned twisted is in stable condition compared with inverse aligned twisted state.In addition, in the liquid crystal display cells of the first embodiment, when not executing alive state and continuing about 2 minutes, occur from inverse aligned twisted shifting again to splash aligned twisted.But when keeping under the state applying certain degree voltage, inverse aligned twisted state can be maintained for a long time.

Present inventors determine the electro-optical characteristic of the liquid crystal display cells of the first embodiment.Fig. 4 (A), (B) represent its result.Fig. 4 (A) represents the relation of applying voltage under splash aligned twisted state and transmittance, and Fig. 4 (B) represents the relation of applying voltage under inverse aligned twisted state and transmittance.The transverse axis of two picture in picture tables represents with unit " V " voltage applied between electrode 12a, 12b, and the longitudinal axis represents the transmittance of liquid crystal display cells with unit " % ".So-called printing opacity, refers to pass through to opposite side from the light of a side side incidence of polaroid 15a, 15b.

Under splash aligned twisted state and inverse aligned twisted state, sharpness (sharpness of change relative to executing alive transmittance) is obviously different, as shown in Fig. 4 (B), known under inverse aligned twisted state relative to the sharpness large (sharpness is excellent) of change executing alive transmittance.

In splash aligned twisted state with against under each state of aligned twisted state, as definition values, calculate V10/V90 and V5/V90.Here, V5, V10, V90 be respectively using the brightest transmittance as 100% time, the magnitude of voltage of the transmittance of 5%, the transmittance of 10%, the transmittance of 90% can be obtained.The result calculated, tries to achieve under splash aligned twisted state, V10/V90=1.746, V5/V90=1.987; Under inverse aligned twisted state, the definition values that V10/V90=1.037, V5/V90=1.041 are such.

For driving definition values required for liquid crystal display cells for less than 1.0465 with the dutycycle of 1/480.Liquid crystal display cells V10/V90, V5/V90 under inverse aligned twisted state of first embodiment can realize this desired value.That is first the liquid crystal display cells of the embodiment dutycycle that inverse aligned twisted state can be used to carry out 1/480 drive such high duty ratio to drive.

On the other hand, for driving definition values required for liquid crystal display cells for less than 1.447 with the dutycycle of 1/8.Liquid crystal display cells V10/V90, V5/V90 under splash aligned twisted state of first embodiment can not realize this desired value.Even if that is known use splash aligned twisted state can not carry out when the dutycycle of carrying out 1/8 drives the display that becomes clear

In addition, drive in (simple matrix driving) in dutycycle, if number of scanning lines be N, forward voltage is V _on, shutoff voltage is V _offtime, their relation represents with following formula (1).

$V_{\mathrm{on}}=\sqrt{\frac{\sqrt{N}+1}{\sqrt{N}-1}}{V}_{\mathrm{off}}\&CenterDot;\&CenterDot;\&CenterDot;\left(1\right)$

The liquid crystal display cells of the second embodiment is described.The liquid crystal material that second embodiment uses is different from the first embodiment.In a second embodiment, the RDR-83107 of (share) DIC is used to form liquid crystal layer as nematic liquid crystal material.The kind of the chiral material added in liquid crystal and addition equal with the situation of the first embodiment.That is chirality spacing is along being 15 μm from upper board towards the direction of lower board in left handed twist direction.

Fig. 5 is the chart of the electro-optical characteristic under the inverse aligned twisted state of the liquid crystal display cells representing the second embodiment.The transverse axis of chart represents with unit " V " voltage applied between electrode, and the longitudinal axis represents the transmittance of liquid crystal display cells with unit " % ".Make the liquid crystal display cells of two the second embodiments, study the relation applying voltage and transmittance for both.

The situation of the first embodiment that the liquid crystal display cells of known second embodiment also represents with Fig. 4 (B) is same, and sharpness is excellent.In addition we know, the individual difference applying voltage-transmittance characteristics is little, and the surplus for unit condition is wider.

The liquid crystal display cells of the 3rd embodiment is described.The liquid crystal material that 3rd embodiment uses is different from the first and second embodiment.In the third embodiment, the RDR-83108 of (share) DIC is used to form liquid crystal layer as nematic liquid crystal material.The kind of the chiral material added in liquid crystal and addition equal with the situation of the first and second embodiment.Chirality spacing is along being 15 μm from upper board towards the direction of lower board in left handed twist direction.

Fig. 6 is the chart of the electro-optical characteristic under the inverse aligned twisted state of the liquid crystal display cells representing the 3rd embodiment.The transverse axis of chart represents with unit " V " voltage applied between electrode, and the longitudinal axis represents the transmittance of liquid crystal display cells with unit " % ".Present inventors have made the liquid crystal display cells of four the 3rd embodiments, apply the relation of voltage and transmittance for the research of each element.

The situation of the second embodiment that the first embodiment that the liquid crystal display cells of known 3rd embodiment also represents with Fig. 4 (B), Fig. 5 represent is same, and sharpness is excellent.In addition we know, the individual difference applying voltage-transmittance characteristics is in the third embodiment also little, and the surplus for unit condition is wider.

In the liquid crystal display cells of the first ~ three embodiment, if the thickness of liquid crystal layer 14 (element thickness) d is 5 μm, chirality spacing p is 15 μm.The value of d/p is 1/3.Element thickness d is not limited to 5 μm.Preferably be used in the value of the amount adjustment d/p of the chiral material added in liquid crystal.

In addition, when TN type liquid crystal display cells, for obtaining the display become clear, the transmittance T when representing the standard black of TN type liquid crystal cells _nBgucci-Terry (グ Star チ テ リ-) formula in, minimum or the second minimal condition of demand fulfillment first.Gucci-Terry formula following formula (2) represents.

$T_{\mathrm{NB}}=\frac{{\sin }^2\left\{(\mathrm{\&pi;}/2)\sqrt{1+u^2}\right\}}{1+u^2}\&CenterDot;\&CenterDot;\&CenterDot;\left(2\right)$

In formula, u is the value calculated with following formula (3).

$u=\frac{2\mathrm{\&Delta;nd}}{\mathrm{\&lambda;}}\&CenterDot;\&CenterDot;\&CenterDot;\left(3\right)$

In formula (3), Δ n is the refractive anisotrop of liquid crystal, and λ is the wavelength of the light inciding liquid crystal cells, and d is as above-mentioned expression element thickness in addition.

For meet Gucci-Terry formula first minimum or the second minimal condition, preferably select liquid crystal material (the refractive anisotrop Δ n of liquid crystal) according to element thickness d.Such as when element thickness d will be made to reduce, increase the value of refractive anisotrop Δ n, otherwise, when element thickness d will be made to increase, reduce the value of refractive anisotrop Δ n, select liquid crystal material in such a way.

In addition, because think that element thickness d is less, the ordered state of liquid crystal molecule is more specified consumingly by the combination of orientation process direction and tilt angle, so the little liquid crystal display cells of presumption units thickness d stably can keep inverse aligned twisted state.

As shown in embodiment, the value of d/p is preferably made to be 1/3 or value near it.But think even if its value has how many changes, also can play same effect.Along with the value of d/p increases, the impact of chiral material manifests consumingly, and splash aligned twisted state easily stably exists.Its result, is produced as and the threshold voltage transferred to required for inverse aligned twisted state from splash aligned twisted state is raised, the tendency that the time that Simultaneous Stabilization remains on inverse aligned twisted state shortens.Therefore, the value of preferred d/p is substantially below 1/2.Think on the other hand, along with the value of d/p diminishes, the distortion produced in the liquid crystal layer that given by chiral material also diminishes, the tendency that sharpness is deteriorated.The addition of chiral material is many, and namely chirality spacing p is little is desirable.The value of preferred d/p is substantially large than 1/2.

In the liquid crystal display cells of the first ~ three embodiment, make the aligning film material that low tilt angle manifests, form alignment films.Present inventors for comparison purpose, have made a kind of liquid crystal display cells, its aligning film material only used compared with the first embodiment and to give the tilt angle of alignment films different.In aligning film material, use the material showing higher tilt angle, give the tilt angle of 21 ° to the alignment films formed.

Fig. 7 represents that tilt angle gets the chart of the electro-optical characteristic under the inverse aligned twisted state of the liquid crystal display cells of 21 °.The transverse axis of chart represents with unit " V " voltage applied between electrode, and the longitudinal axis represents the transmittance of liquid crystal display cells with unit " % ".Make the liquid crystal display cells that four impart 21 ° of tilt angles, apply the relation of voltage and transmittance for the research of each element.

Four liquid crystal display cells of tilt angle 21 ° have individual difference, but the threshold value of all driving voltages is all low.But the excellent sharpness can't see as shown in Fig. 4 (B).The result represented from Fig. 7 is thought, for realizing excellent sharpness, preferably using the aligning film material manifesting low tilt angle to form alignment films, the alignment films formed being implemented to the orientation process of giving low tilt angle.

Present inventor is studied about the inverse sharpness of TN type liquid crystal display cells and the relation of tilt angle.First the controlling of tilt angle is described.Present inventors confirm, are used in the polyimide material ((share) チ Star ソ petrochemistry PIA-768-01X) showing high tilt angle and with the addition of the polyimide material ((share) チ Star ソ petrochemistry PIA-359-01X) showing low tilt angle and two kinds that the obtain alignment films mixing polyimide material formation can manifest tilt angle continuously.

Fig. 8 is the chart of the relation of the mixing ratio representing two kinds of polyimide materials and the tilt angle manifested.The transverse axis of chart represents containing than (concentration) of the PIA-768-01X mixed in polyimide material with unit " % ", and the longitudinal axis represents the size of the tilt angle manifested with unit " ° ".When measuring tilt angle, use the liquid crystal material ZLI4792 of (share) メ Le Network.Known from this figure, the ratio that contains of tilt angle and polyimide material PIA-768-01X proportionally increases.Therefore, by the mixing ratio of adjustment polyimide material PIA-768-01X and PIA-359-01X, the continuous print that can realize the tilt angle manifested controls.

The following describes the liquid crystal display cells of the 4th embodiment and the first ~ three comparative example.4th embodiment is the liquid crystal display cells defining alignment films with the mixing polyimide material that the mixing ratio of alignment film of polyimide material PIA-768-01X and PIA-359-01X gets 20: 80, and the first ~ three comparative example is have mixing ratio to get 45: 55,40: 60,30: 70 and the liquid crystal display cells of alignment films that formed successively.

The method manufacture same with the manufacture method that reference Fig. 1 illustrates used for liquid crystal display element of the 4th embodiment.Difference and additional details as follows.

Being on the foursquare glass substrate (thickness 1.1mm) of 2cm a pair length of side, forming foursquare ITO electrode that the length of side is 1cm and for making the peripheral electrode of itself and turned on outside.When forming alignment films, the alignment films polyimide material of coating thickness about 0.1 μm on the glass substrate, this alignment films polyimide material mixes with the PIA-359-01X ratio of 20% (share) チ Star ソ petrochemistry PIA-768-01X and 80%.The cut velvet cloth of kapok is used in friction treatment.When stickup a pair glass substrate, frictional direction gets mutually orthogonal direction.Specifically, using the frictional direction of upside orientation film as first direction, using the frictional direction of downside alignment films as second direction time, second direction is using first direction as benchmark, direction in 90 ° viewed from the normal direction of upper board.Splash structure is not comprised at liquid crystal material, more specifically, such as, when being configured with the liquid crystal material not comprising chiral material between this alignment films, the tilt angle of that the direction of the friction treatment by upper board is determined, that tilt angle is formed direction (direction that liquid crystal molecule erects relative to substrate) and lower board towards combination as the combination becoming the homogeneous texture reversing 90 ° in right direction.

In the alignment films of a glass substrate, scatter after changing into HIPRESICA processed (Ha イ プ レ シ カ) UF as (share) Yu Bu East of the silicon gap control material of diameter 5 μm, at the periphery coating epoxy encapsulant of glass substrate, at the temperature of 150 DEG C, heating makes it harden in 1 hour.Inlet and the exhausr port for injecting liquid crystal material is made at hermetic unit.

The dummy cell prepared like this is placed on hot plate, in the space utilizing capillarity that liquid-crystal composition is injected into from inlet to fence up with encapsulant.Liquid crystal material uses the RDP-83409 of (share) DIC.Chiral material is added in liquid crystal.Adjustment addition makes chirality spacing along becoming 15 μm from upper board towards the direction of lower board at right torsional direction.After the injection of liquid-crystal composition terminates, inlet and exhausr port configure epoxy bonding agent, place and sclerosis was sealed in one.By the state of orientation of polarized light microscope observing liquid crystal, confirm to obtain whole uniform state of orientation.In addition, with (result that the liquid crystal cell tilt angle determinator PAS-001 of share) East Yang テ Network ニ Network measures is be about 5 ° to the tilt angle that alignment films is given.

By confirming the applying voltage-transmittance characteristics of this state, observing the driving voltage threshold value higher than common TN type liquid crystal display cells, distinguishing and define the twist structured liquid crystal cell of splash.In addition, between the electrode of this liquid crystal cell, apply the square-wave voltage of 10V, make liquid crystal molecule keep the state of less perpendicular arrangement relative to substrate, thus find change in the tone of liquid crystal molecule.The change of tone produces partly, and the part that tone changes slowly expands, and several minutes periods expanded to whole.In the region that tone changes, think and there occurs from splash aligned twisted state to the transfer against aligned twisted state.Inverse aligned twisted state also exists between tens of second after stopping applies voltage, but transfers to again splash aligned twisted state afterwards.

Fig. 9 is the chart of the relation of applying voltage under the inverse aligned twisted state of the liquid crystal display cells representing the 4th embodiment and transmittance.The transverse axis of chart represents with unit " V " voltage applied between electrode, and the longitudinal axis represents the transmittance of liquid crystal display cells with unit " % ".Present inventors have made the liquid crystal display cells of four the 4th embodiments, have studied the relation applying voltage and transmittance for each element.(the LCD5200 as liquid crystal cell electro-optical characteristic detecting apparatus that share) great mound Electricity makes is used in mensuration.

Make 4 liquid crystal display cells in one in, Fig. 4 (B) can be found out, Fig. 5 and Fig. 6 represents, with the same excellent sharpness of the first ~ three embodiment, can't see in remaining 3.Think thus in inverse TN type liquid crystal display cells, the Optimality of sharpness does not change continuously according to tilt angle, and with 5 ° of such tilt angles for boundary, under the tilt angle giving upper and lower base plate is all greater than 0 ° and is less than or equal to 5 ° of such conditions, manifest the Optimality of sharpness.

Figure 10 (A) to (C) represents the relation of applying voltage under the inverse aligned twisted state of the liquid crystal display cells of the first ~ three comparative example and transmittance respectively.As above-mentioned, the first ~ three comparative example is the liquid crystal display cells defining alignment films with the mixing polyimide material that the mixing ratio of alignment film of polyimide material PIA-768-01X and PIA-359-01X gets 45: 55,40: 60,30: 70.The liquid crystal display cells of the first ~ three comparative example, except mixing ratio this point different of aligning film material, manufactures with the direction equal with the 4th embodiment.In addition, about each comparative example, make multiple liquid crystal cells.The transverse axis of the chart of Figure 10 (A) ~ (C) represents with unit " V " voltage applied between electrode, and longitudinal axis unit " % " represents the transmittance of liquid crystal display cells.

Chart according to Fig. 8 judges, thinks that Figure 10 (A) is middle and represents that the tilt angle of first comparative example (mixing ratio 45: 55) of electro-optical characteristic is 15 ° strong.Think in addition Figure 10 (B), represent second comparative example (mixing ratio 40: 60) of electro-optical characteristic in (C), the tilt angle of the 3rd comparative example (mixing ratio 30: 70) be respectively 15 ° weak and 7 ~ 8 °.

From the result that Figure 10 (A) represents to (C), in the first ~ three comparative example, can't see the Optimality of the sharpness under inverse aligned twisted state.In addition, also reaffirmed that the Optimality of sharpness is not according to tilt angle continually varying.

As above-mentioned, excellent sharpness characteristic manifests under tilt angle is greater than 0 ° and is less than or equal to 5 ° of such conditions.In addition as has been described like that, the ratio d/p of the thickness d of preferred liquid crystal layer and the chirality spacing p of chiral material is greater than 1/4 and is less than or equal to 1/2.

Present inventors have made the inverse TN type liquid crystal display cells of thickness d=5 μm of liquid crystal layer, chirality spacing p=20 μm, d/p=1/4, thickness d=5 μm of the inverse TN type liquid crystal display cells of pretilt theta=1 ° and liquid crystal layer, chirality spacing p=20 μm, d/p=1/4, pretilt theta=5 °, the electro-optical characteristic under the inverse aligned twisted state of research.Its result, can't see the sharpness excellent like that seen in embodiment.Think thus, at tilt angle more than 1 ° when less than 5 °, it is to obtain the excellent necessary condition of sharpness characteristic that d/p is greater than 1/4.

The inverse TN type liquid crystal display cells of embodiment former state to keep can not wanting optical compensation plate and obtaining white black display, easily can manufacture with low cost, visual angle is wider, the advantage of the TN type liquid crystal display cells that response high speed is such, and the liquid crystal display cells of excellent sharpness can be realized.Because sharpness is excellent, so such as when carrying out simple matrix driving, can show by the large capacity of display.

In addition, because be the liquid crystal display cells of low tilt angle, so the aligning film material manufacture used for liquid crystal display element of the TN type of widely used high reliability in the industry can be used, be therefore the liquid crystal display cells with high reliability.

Further, the liquid crystal display cells of embodiment can drive with 1/480 dutycycle.In simple matrix drives, it is the driving using most high duty cycle number that 1/480 dutycycle drives.Therefore applied range, such as, utilizes in the liquid crystal display cells that can drive at nearly all simple matrix.

In addition, because the number of electrodes of excellent sharpness characteristic public electrode (upside ITO electrode 12a, downside ITO electrode 12b either party) is many, such as, can makes more than 100, can show with high display performance.

Figure 11 is the boundary voltage of the liquid crystal display cells gathering expression the first ~ four embodiment and the table of the physics value of liquid crystal material that uses in each liquid crystal display cells.V in table _cthe measured value of the boundary voltage of liquid crystal display cells is represented with unit " V ".So-called boundary voltage, refers to, when slowly reducing the applying voltage of the liquid crystal display cells be under aligned twisted state, return to the voltage of splash aligned twisted state.Δ _εrepresent the dielectric constant anisotropy of liquid crystal material.In addition, K ₁₁, K ₂₂, K ₃₃extension elastic constant, elasticity of torsion constant, the bend elastic constant of liquid crystal material is represented respectively with unit " pN ".Further, γ 1 represents the rotary viscosity of liquid crystal material with unit " mPas ".

Boundary voltage V _cless liquid crystal display cells is more stable under inverse aligned twisted state.Therefore, in the making of inverse TN type liquid crystal display cells, preferably select to make boundary voltage V _clittle liquid crystal material or cellular construction.

In addition, the result of the research of present inventors, knows in the inverse TN type liquid crystal display cells of embodiment, K ₁₁zhi Yue Datong District time K ₂₂value less, the stability of inverse aligned twisted state is higher.From the view point of the stability of inverse aligned twisted state, preferably use extension elastic constant K ₁₁with elasticity of torsion constant K ₂₂ratio " K ₁₁/ K ₂₂" be more than 2 liquid crystal material formed liquid crystal layer.

Physics value in the table using Figure 11 to represent illustrates the feature of the liquid crystal display cells of embodiment.Following formula (4) calculates the threshold voltage V that tilt angle is the driving voltage of general inverse TN type liquid crystal display cells under inverse aligned twisted state of 0 _thformula.

$V_{\mathrm{th}}=\mathrm{\&pi;}\sqrt{\frac{K}{{\mathrm{\&epsiv;}}_0\left|\mathrm{\&Delta;\&epsiv;}\right|}}\&CenterDot;\&CenterDot;\&CenterDot;\left(4\right)$

ε in formula (4) ₀represent the specific inductive capacity (8.85418782 × 10 of vacuum ^-12f/m).K is the value calculated by following formula (5) when twist angle is the inverse TN type liquid crystal display cells of 90 ° in addition.

$K=k_{11}+\frac{1}{4}(K_{33}-2K_{22})\&CenterDot;\&CenterDot;\&CenterDot;\left(5\right)$

When general tilt angle is 0 °, the threshold value of driving voltage becomes maximum.That is tilt angle is not the magnitude of voltage V that threshold value ratio formula (4) of the driving voltage of the inverse TN type liquid crystal display cells of 0 ° and formula (5) are tried to achieve _thlittle.Therefore, the threshold value of the driving voltage of the liquid crystal display cells of the such as first ~ four embodiment should compare V _thlittle.

With reference to the table of Figure 11, the physics value of the liquid crystal material of the liquid crystal layer of the liquid crystal display cells of formation the first ~ four embodiment is substituted into (4) and (5), calculates V as follows _th.

When RDP84910 (the first embodiment), V _th≒ 0.62V.

When RDP83107 (the second embodiment), V _th≒ 0.89V.

When RDP83108 (the 3rd embodiment), V _th≒ 0.89V.

When RDP83409 (the 4th embodiment), V _th≒ 0.98V.

But when with reference to Fig. 4 (B), the threshold value (switching voltage: during applying voltage, transmittance starts the magnitude of voltage changed) of the driving voltage of the liquid crystal display cells of the first embodiment is 1.2 ~ 1.3V, and this is V _thabout 2 times of ≒ 0.62V.In addition, when with reference to Fig. 5, the threshold value of the driving voltage of the liquid crystal display cells of the second embodiment is about 1.8V, is V _thabout 2 times of ≒ 0.89V.And then when with reference to Fig. 6, the threshold value of the driving voltage of the liquid crystal display cells of the 3rd embodiment is 1.5 ~ 1.7V, and this is more than V _th1.5 times of ≒ 0.89V.In addition, when with reference to Fig. 9, the threshold value of the driving voltage of the liquid crystal display cells of the 4th embodiment is 1.3 ~ 1.5V.This is V _thmore than 1.3 times of ≒ 0.98V.Like this, the liquid crystal display cells of embodiment has at the threshold voltage V tried to achieve by formula (4) and formula (5) _ththe threshold value of the large driving voltage of more than 1.3 times.

Figure 12 represents an example of the waveform of the driving voltage applied between upside ITO electrode 12a, downside ITO electrode 12b by power supply 20.The horizontal axis representing time of figure, the longitudinal axis represents magnitude of voltage." select waveform Vs " and represent that " non-selection waveform Vus " represents the driving voltage waveform applied on non selected pixels in the driving voltage waveform selecting pixel applies.

When driving the liquid crystal display cells of embodiment, moment is not only being selected pixel but also on non selected pixels, is such as pressing the higher voltage that some cycles applies the such waveform of diagram.Therefore, in the liquid crystal display cells of embodiment, first between two electrode 12a, 12b, apply the voltage of more than threshold voltage, after making the ordered state of liquid crystal molecule 14a transfer to inverse aligned twisted from splash arrangement, if carry out common dutycycle driving, then can not apply transfer voltage for a long time and continue display.Now, because it is higher to show then peak voltage with the driving of higher dutycycle, so think that inverse aligned twisted state is more stable.From this viewpoint, the liquid crystal display cells of preferred embodiment is taken as the dutycycle higher than 1/120 dutycycle the drive condition that simple matrix drives and drives.

Finally, about the reason manifesting excellent sharpness under the inverse aligned twisted state of inverse TN type liquid crystal display cells, the opinion of the hypothesis of present inventors is described.

Such as about the inverse TN type liquid crystal display cells that the patent documentation 3 of the earlier application as present inventors is recorded, transmittance etc. when turning off from simulation or voltage is known, under inverse aligned twisted state, even if when voltage turns off, the liquid crystal molecule near the central authorities of the thickness direction of liquid crystal layer becomes the state erected slightly by internal distortions.If the threshold value of the driving voltage of inverse TN type liquid crystal display cells is low is due to this state, then can think for making liquid crystal molecule less perpendicular on substrate erect the little namely passable cause of required voltage.In addition, in the inverse TN type liquid crystal display cells (standard white type) that patent documentation 3 is recorded, although know that transmittance when voltage turns off under inverse aligned twisted state is lower than the transmittance during shutoff of voltage under splash aligned twisted state, think that this is also because the liquid crystal molecule near the central authorities of the thickness direction of liquid crystal layer becomes the state erected slightly when voltage turns off.

But, when comparing reference example as represented Fig. 4 (A), (B) of the electro-optical characteristic of the liquid crystal display cells of the first embodiment, the transmittance when transmittance when voltage under inverse aligned twisted state turns off turns off than the voltage under splash aligned twisted state is large on the contrary.In addition, even if about the threshold value (transmittance starts applying voltage when reducing) of driving voltage, be also that inverse aligned twisted state is large.

From these true suppositions, in the liquid crystal display cells of embodiment, when under inverse aligned twisted state, voltage turns off, although large distortion should be had in liquid crystal layer inside, liquid crystal molecule near the central authorities in thickness of liquid crystal layer direction erects hardly, substantially parallel-oriented with real estate.Then under executing alive situation to the liquid crystal display cells of embodiment, think because the liquid crystal molecule near the central authorities of thickness of liquid crystal layer direction erects hardly, so when not applying the high voltage to certain degree, liquid crystal molecule does not tilt to direction of an electric field, even if but start a little to tilt, by the electric field larger than repressed internal distortions, sharply there is the change in the direction of liquid crystal directors, by small voltage difference, liquid crystal molecule near the central authorities of thickness of liquid crystal layer direction just almost vertically erects, and realizes excellent sharpness thus.

But although should have large distortion in liquid crystal layer inside, the reason that the liquid crystal molecule near the central authorities of thickness of liquid crystal layer direction erects hardly is also indefinite.Think to cause in liquid crystal layer with the interpolation by chiral material there is large distortion, the tilt angle of giving alignment films is little, the value that forms the elastic constant of the liquid crystal material of liquid crystal layer etc. is relevant.

In addition, according to the observation, under the inverse aligned twisted state of inverse TN type liquid crystal display cells, at pretilt theta and p/d (p: chirality spacing, d: element thickness) ratio " θ/(p/d) " larger than certain value when, do not executing under alive state, the phenomenon that the liquid crystal molecule near the thickness direction central authorities manifesting liquid crystal layer erects.According to the research of present inventors, when θ/(p/d) is larger than 2 °, erecting of the liquid crystal molecule near the thickness direction central authorities that can observe liquid crystal layer.Therefore, meet in the inverse applying voltage of TN type liquid crystal display cells of this condition and the chart of the relation of transmittance in expression, cannot see threshold property, transmittance changes from 0V.

On the other hand, when θ/(p/d) is below 2 °, do not executing under alive state, the phenomenon that the liquid crystal molecule near the thickness direction central authorities not observing liquid crystal layer erects, in the chart representing the relation applying voltage and transmittance, seeing threshold property sharply.That is under the condition of following formula (6), manifest excellent sharpness.

In formula,

$\frac{1}{4}<\frac{d}{p}\&le;\frac{1}{2}\&DoubleLeftRightArrow;2\&le;\frac{p}{d}<4\&CenterDot;\&CenterDot;\&CenterDot;\left(7\right)$

0°＜θ≤5°…(8)

Figure 13 (A) and (B) are the charts of the example of the scope of pretilt theta and the p/d representing that sharpness excellent in inverse TN type liquid crystal display cells occurs.In two charts, transverse axis represents p/d, and the longitudinal axis represents pretilt theta with unit " ° ".Draw and have the region of oblique line (borderline region comprises solid line portion, does not comprise dotted line part.Do not comprise the point drawn and have white circle in addition.) meet formula (6) to (8).

The straight line I of Figure 13 (A) _a, Figure 13 (B) straight line I _bto be all degree of tilt be 2 straight line.That is, straight line I _a, I _bbe included in the straight line group represented with following formula (9).

$\mathrm{\&theta;}=2\left(\frac{p}{d}\right)+\mathrm{\&beta;}\&CenterDot;\&CenterDot;\&CenterDot;\left(9\right)$

In formula (9), β is the constant depending on liquid crystal material.At the straight line I of Figure 13 (A) _amiddle β=-1, at the straight line I of Figure 13 (B) _bmiddle β=1.The situation of β=± 1 shown in Figure 13 (A) and (B), but according to the liquid crystal material used in inverse TN type liquid crystal display cells, θ gets the value beyond this, and the degree of tilt of delimiting the region (combination of θ and p/d) that fine details occur in this liquid crystal display cells is the straight line lifting of 2.Therefore, the scope realizing the combination of θ and p/d of excellent sharpness is also different according to liquid crystal material.

Describe the present invention to this according to embodiment, but the present invention is not limited thereto.

Such as, in an embodiment, the twist angle under inverse aligned twisted state gets 90 °, but also can change in the scope (70 ° ~ 110 °) of about ± 20 °.But when considering the lightness of white display, preferably get 90 ° or twist angle near it.

In addition, in an embodiment, the angle through axle formation of upside polaroid and lower-side polarizing plate is got 90 ° (Niccol that intersects configures), but the angle through axle formation of two polaroids can change in the scope of about ± 5 °.But the angle leaked through from preventing light is considered, preferably configure with 90 ° or angle near it.In addition, polaroid is configured to parallel polarization sheet, also can as the liquid crystal display cells of standard black type.In that occasion, the angle formed through axle can be made such as to get the scope of less than 20 ° to configure polaroid.

In addition, professional understands and can carry out various change, improvement, combination etc.

Liquid crystal display cells generally can utilize in the OA equipment liquid crystal display cells such as vehicle-mounted liquid crystal display cells, duplicating machine carrying out the various display such as audio frequency display, thermal control display.In addition, the liquid crystal display cells that can drive at simple matrix, utilizes in liquid crystal display cells when particularly requiring the large capacity of display.

Claims (7)

1. a liquid crystal display cells, it has:

First substrate, it has the first electrode, has been carried out orientation process in a first direction;

Second substrate, itself and above-mentioned first substrate are oppositely disposed abreast, have the second electrode, have been carried out orientation process in a second direction; With

Liquid crystal layer, it is configured between above-mentioned first substrate and above-mentioned second substrate, comprises chiral material, carries out twisted-oriented,

Above-mentioned second direction is the normal direction from above-mentioned first substrate side, on the first gyratory directions, the direction of 70 ° ~ 110 ° is become relative to above-mentioned first direction, above-mentioned first gyratory directions is the gyratory directions of the liquid crystal molecule that the combination in the direction of the orientation process applied on the above-mentioned first substrate and above-mentioned second substrate of the above-mentioned liquid crystal layer of clamping limits

The liquid crystal molecule of above-mentioned liquid crystal layer along above-mentioned first gyratory directions twisted arrangement,

From the normal direction of above-mentioned first substrate side, above-mentioned chiral material gives the turning quality towards second gyratory directions contrary with above-mentioned first gyratory directions along from above-mentioned first substrate towards the direction of above-mentioned second substrate to the liquid crystal molecule of above-mentioned liquid crystal layer,

Above-mentioned first substrate and above-mentioned second substrate are oriented to be processed into manifest and are greater than 0 ° and the pretilt theta being less than or equal to 5 °,

When set the thickness of above-mentioned liquid crystal layer as the chirality spacing of d, above-mentioned chiral material be p time, above-mentioned θ, above-mentioned d and above-mentioned p meet following formula (1) and (2),

$2\&le;\frac{p}{d}<4\&CenterDot;\&CenterDot;\&CenterDot;\left(1\right)$

2. liquid crystal display cells according to claim 1, wherein,

When setting the extension elastic constant of the liquid crystal material forming above-mentioned liquid crystal layer as K ₁₁, elasticity of torsion constant is K ₂₂time, above-mentioned K ₁₁with above-mentioned K ₂₂meet following formula (3),

$\frac{K_{11}}{K_{22}}\&GreaterEqual;2\&CenterDot;\&CenterDot;\&CenterDot;\left(3\right).$

3. liquid crystal display cells according to claim 1, wherein,

Above-mentioned second direction is the normal direction from above-mentioned first substrate side, relative to the direction that above-mentioned first direction is in 90 ° on above-mentioned first gyratory directions.

4. liquid crystal display cells according to claim 1, wherein,

Above-mentioned first substrate and above-mentioned second substrate are oriented the pretilt theta being processed into and manifesting more than 1 ° less than 5 °.

5. liquid crystal display cells according to claim 1, wherein,

Above-mentioned second electrode is public electrode, and the number of electrodes of above-mentioned public electrode is more than 100.

6. liquid crystal display cells according to claim 1, wherein,

Above-mentioned liquid crystal display cells also comprises:

Be configured in the first polaroid of the opposition side of the above-mentioned liquid crystal layer of above-mentioned first substrate, and

Be configured in the second polaroid of the opposition side of the above-mentioned liquid crystal layer of above-mentioned second substrate,

Above-mentioned liquid crystal layer, by the voltage applied between above-mentioned first electrode and above-mentioned second electrode, is switchably created on the even distorted-structure that above-mentioned first gyratory directions reverses and the splash distorted-structure reversed on above-mentioned second gyratory directions,

In above-mentioned even distorted-structure, when applying voltage between above-mentioned first electrode and above-mentioned second electrode, be magnitude of voltage V from the light of the side side incidence in above-mentioned first polaroid, above-mentioned second polaroid by the magnitude of voltage changed the amount to the opposing party side _thmore than 1.3 times, above-mentioned magnitude of voltage V _thsetting the elasticity of flexure coefficient of the liquid crystal material forming above-mentioned liquid crystal layer as K ₃₃, dielectric constant anisotropy is Δ ε, the specific inductive capacity of vacuum is ε ₀in time, tries to achieve with following formula (4) and (5),

$V_{\mathrm{th}}=\mathrm{\&pi;}\sqrt{\frac{K}{{\mathrm{\&epsiv;}}_0\left|\mathrm{\&Delta;\&epsiv;}\right|}}\&CenterDot;\&CenterDot;\&CenterDot;\left(4\right)$

$K=K_{11}+\frac{1}{4}(K_{33}-2K_{22})\&CenterDot;\&CenterDot;\&CenterDot;\left(5\right).$

7. liquid crystal display cells according to claim 1, wherein,

The drive condition that simple matrix drives is set to the dutycycle higher than 1/120 dutycycle drive.