JP3551059B2 - Liquid crystal display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate light leakage originated from spacer beads in a horizontal electric field mode normally closed type and to improve a contrast ratio by controlling optical leak centering a spacer to become a quadripartite form. SOLUTION: In this normally closed type liquid crystal display, an active matrix type liquid crystal display device wherein it adopts the horizontal electric field mode and a pre-tilt angle between an alignment control film and liquid crystal is set to 4 degrees or less, optical leak centering a spacer is controlled so as to become a quadripartite form 41. As a method of making the quadripartite formed spacer appear with priority, it is achievable to make liquid crystal molecules on a spacer surface to be aligned almost parallel by making a contact angle between the spacer and the liquid crystal to 60 deg.C or lower. To make the contact angle between the spacer and the liquid crystal to 60 deg.C or lower, to be more specific, a functional group acting as a wetting agent with liquid crystal is recommended to be introduced on the surface of the spacer.

Description

【００８６】
上記結果から、以下のことを明らかにできた。
【００８７】
極性基を持たないニュートラル系液晶では、垂直配向性が強くなる。これは、極性を有する官能基がスペーサ表面との湿潤剤のような作用を示すと考えられる。また、例ｃ，ｄによって、スペーサの表面にアルキル基や水酸基等の官能基を導入することによって、ぬれ性を改善することができ、スペーサの光漏れ低減効果が得られる。これはスペーサ表面の官能基が湿潤剤たる効果を有している。従って、液晶もしくはスペーサ表面に、両者のぬれ性をよくする湿潤剤となる作用を有する官能基を導入することが、効果的であることがわかる。これらの作用は、両者の分子間引力とおのおのの凝集力との差に起因するものであるから、分子間の引力が強くなる組み合わせを達成すれば効果が得られる。本実施例の化合物に限定されるものではない。
【００８８】
例ｆのプレチルト角はほぼ０度である。液晶とスペーサの接触角を著しく低減して水平配向性を強く付与し、さらに配向制御膜と液晶の接触角も著しく低減してしまうと、図１の領域４８で示す領域の液晶分子は、スペーサ表面で水平配向が安定状態となり、２分割が優先されてしまうことがわかる。従って、特に、液晶とスペーサの接触角が著しく低い場合には、配向制御膜と液晶の接触角の値を制御することが重要であることがわかる。
【００８９】
【発明の効果】
上述のように、本発明によればコントラストの高い液晶表示装置を実現できる。
【図面の簡単な説明】
【図１】本発明の液晶表示装置におけるスペーサ周辺の配向の模式図。
【図２】本発明の液晶表示装置におけるスペーサ周辺の配向の模式図。
【図３】本発明の液晶表示装置のパネルの模式断面図。
【図４】電界方向に対する液晶分子長軸配向方向と偏光板偏光透過軸のそれぞれがなす角を示す図。
【図５】横電界方式の液晶表示装置における液晶の動作原理を示す図。
【図６】本発明の一実施例である単位画素部の電極群，絶縁膜，配向制御膜の配置を示す平面、及び断面を示す模式図。
【図７】本発明の液晶表示装置における回路システム構成の一例を示す図。
【図８】本発明の液晶表示装置における光学系システム構成の一例を示す図。
【図９】本発明の一実施例による液晶表示装置のパネルの模式断面図。
【図１０】本発明の液晶表示装置の分解構成斜視図。
【図１１】本発明の液晶表示装置における特性を説明する図。
【符号の説明】
１，１′…基板、２…共通電極、３…画素電極、４…絶縁層、５…カラーフィルタ、６…液晶分子、８，８′…液晶配向能が付与された配向制御膜、９，９′…偏光板、１０…映像信号電極、１１…液晶分子長軸の配向方向、１２…偏光板透過軸方向、１３…電界方向、１４…走査電極（ゲート配線電極）、１５…薄膜トランジスタ、１６…アモルファスシリコン（ａ−Ｓｉ）、１７…垂直走査信号回路、１８…映像信号回路、１９…共通電極駆動用回路、２０…電源回路及びコントローラ、２１…光源、２２…ライトカバー、２３…導光体、２４…拡散板、２５…プリズムシート、２６…バックライトユニット、２７…液晶パネル、２９…電極群、３０…液晶層、４０…スペーサ、４１…光漏れ領域、４２…液晶分子配向能を有する表面層、４５…配向制御膜の配向方向に従う液晶分子、４６…スペーサビーズ表面により配向制御膜の配向方向に対して乱され光漏れを生じる液晶分子、４７…クロスニコルによって消光位となる液晶分子、４８…配向制御膜の配向方向とスペーサビーズ表面の平行配向方向がほぼ９０度なる領域、４９…配向制御膜の配向方向とスペーサビーズ表面の平行配向がほぼ一致する領域。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a so-called lateral electric field type liquid crystal display device which operates by applying an electric field to a liquid crystal layer in a direction substantially parallel to a substrate, and more particularly to a lateral electric field type liquid crystal display having a wide viewing angle characteristic. The present invention relates to a display panel having a high black level in dark display and high image quality in an apparatus.
[0002]
[Prior art]
In the liquid crystal display device, the level of the dark display is almost the main factor that governs the contrast ratio of the liquid crystal display device. In addition, factors that deteriorate the level of the sinking of the dark display include light leaks at pixel ends, electrode ends, frame responses, spacers, and the like.
[0003]
For a liquid crystal display device, if the thickness of the liquid crystal layer varies, display quality such as contrast reduction, brightness unevenness, and color unevenness is significantly reduced. Therefore, a spacer is required to keep the thickness of the liquid crystal layer constant.
[0004]
However, the spacer disturbs the alignment of the liquid crystal molecules in the vicinity of the surface, thereby causing light leakage as described above. In order to suppress the fluctuation of the thickness of the liquid crystal layer, the effect is higher as the in-plane scatter density of the spacer is higher, but the contrast ratio is remarkably reduced. Also, light leakage around the spacer may cause glare that the screen does not look uniform black from dark display to halftone, and uneven brightness due to local concentration of spacers. Also.
[0005]
2. Description of the Related Art Conventionally, in a vertical electric field type normally closed liquid crystal display device in which a liquid crystal is operated by applying an electric field in a vertical direction to a substrate surface (hereinafter, referred to as a vertical electric field type), liquid crystal molecules are vertically applied to a spacer surface. There has been proposed a method (Japanese Patent Laid-Open No. 4-177324, etc.) for introducing a function of aligning to reduce light leakage around the spacer. Although this method is effective in a vertical electric field type normally closed type liquid crystal display device, a method for reducing a unique spacer light leakage occurring in a horizontal electric field type normally closed type liquid crystal display device targeted by the present invention is described. Not mentioned.
[0006]
[Problems to be solved by the invention]
In a conventional vertical electric field TN mode normally open liquid crystal display device, dark display can be obtained with a high voltage applied. In this case, at high voltage, most of the liquid crystal molecules are aligned in the direction of the electric field which is one direction perpendicular to the substrate surface, and a black level is obtained by the relative relationship between the arrangement of the liquid crystal molecules and the arrangement of the polarizing plate. I have. Therefore, the uniformity of the black level does not depend much on the initial alignment state at low voltage in principle.
[0007]
Further, the human eye recognizes luminance unevenness as a relative ratio of luminance and reacts on a logarithmic scale, and is therefore sensitive to fluctuations in black level. From this viewpoint, the conventional TN mode normally open type liquid crystal display device in which liquid crystal molecules are forcibly arranged in one direction at a high voltage is insensitive to the initial alignment state, which is advantageous.
[0008]
On the other hand, the horizontal electric field type normally closed type liquid crystal display device is very sensitive to disturbance of the initial alignment state because a black level is displayed at a low voltage or zero voltage. In particular, in a birefringent mode arrangement in which the liquid crystal molecule alignment is made to be a homogeneous arrangement in which the upper and lower substrates are parallel to each other, the transmission axis of one polarizing plate is parallel to the liquid crystal molecule alignment direction, and the other polarizing plate is orthogonal. Polarized light incident on the layer propagates with little disturbance of linearly polarized light. This is effective for lowering the black level, and in principle, an ideal black display is possible.
[0009]
However, in principle, ideal black display is possible, but conversely, slight initial alignment disturbance directly leads to light leakage, which hinders sinking during dark display and reduces black level. It will make it worse.
[0010]
In general, the transmissivity T of the birefringence mode in the in-plane switching mode liquid crystal display device can be expressed by the following equation (1).
[0011]
T = T0 · sin2 ｛2θ (E)｝ · sin2 ｛(π · def · Δn) / λ｝ (1)
Here, T0 is a coefficient, a value determined mainly by the transmittance of the polarizing plate used for the liquid crystal panel, θ (E) is the angle between the effective optical axis of the liquid crystal layer and the polarization transmission axis, E is the electric field strength, def is the effective thickness of the liquid crystal layer, Δn is the anisotropy of the refractive index of the liquid crystal, and λ is the wavelength of light. Here, the product of the effective thickness deff of the liquid crystal layer and the anisotropy Δn of the refractive index of the liquid crystal, that is, deff · Δn, is referred to as retardation. Note that the thickness def of the liquid crystal layer here indicates not the thickness of the entire liquid crystal layer but only the thickness of the liquid crystal layer that actually changes the alignment direction when a voltage is applied. This is because the liquid crystal molecules in the vicinity of the interface of the liquid crystal layer do not change their alignment direction even when a voltage is applied due to the effect of anchoring at the interface. Therefore, the thickness of the entire liquid crystal layer sandwiched between the substrates is represented by d. _LC Then, there is always a relationship of deff <dLC between the thickness dLC and the deff, and the difference differs depending on the material used for the liquid crystal panel and the interface in contact with the liquid crystal layer, for example, the type of the alignment film material. It can be estimated to be about 40 nm.
[0012]
As is clear from the above equation (1), it is the term of sin2 {2θ (E)} that depends on the electric field intensity, and the luminance can be adjusted by changing the angle θ according to the electric field intensity E. In order to obtain a normally-closed type, the polarizing plate is set so that θ = 0 ° when no voltage is applied, so that the polarizing plate acts so as to be sensitive to disturbance in the initial alignment direction.
[0013]
As described above, in the in-plane switching mode normally closed type liquid crystal display device which is sensitive to the disturbance of the initial alignment direction, light leakage around the spacer is a main factor inhibiting the dark display from sinking. This is because, at the interface between the spacer and the liquid crystal, the liquid crystal is aligned on the spacer surface, contrary to the alignment control film for aligning in a predetermined direction.
[0014]
The reason that the spacer interface functions like an alignment control film and aligns the liquid crystal is not limited to the horizontal electric field method. However, as described above, in the normally open TN method of the vertical electric field method, light leakage due to disturbance in the initial alignment direction does not significantly affect the TN method. In the STN mode, which is a vertical electric field type normally closed type, conventionally, a method of giving a function of vertically aligning liquid crystal molecules on the surface of the spacer beads has been adopted. This is for the following reason.
[0015]
When the liquid crystal molecules are aligned parallel to the surface of the spacer beads, whether they are parallel or perpendicular to the substrate is equivalent. In a vertical electric field type normally closed liquid crystal display device, an electric field is applied in a direction perpendicular to a substrate, and display is performed by operating liquid crystal molecules in parallel with the direction of the electric field. The misalignment causes a fatal increase in light leakage. That is, since the vertical electric field method is a method in which liquid crystal molecules rise in the polar angle direction during driving, the state in which the liquid crystal molecules rise in the polar angle direction is parallel alignment when viewed from the interface between the spacer beads and the liquid crystal, and becomes a stable state. Would. Therefore, it is almost impossible to control the orientation to be parallel so as to prevent rising in the polar angle direction. Therefore, conventionally, a method of improving the vertical alignment function by providing the spacer beads with a function has been adopted. In other words, this is because the rising of the liquid crystal molecules in the polar angle direction where light leakage is remarkable is in an unstable state.
[0016]
However, in the case of the lateral electric field method, the rising in the polar angle direction does not affect the light leakage, but the misalignment in the azimuthal direction causes a fatal increase in the light leakage. Vertically oriented spacer beads cause misalignment in the azimuthal direction, so if the vertically oriented spacer beads used in the vertical electric field type liquid crystal display are applied to the horizontal electric field type liquid crystal display, light leakage will occur. Causes an increase. Therefore, the conventional method cannot reduce the light leakage of the spacer beads in the in-plane switching mode normally closed liquid crystal display device.
[0017]
In other words, this is a problem that does not occur in the STN system employing the same birefringence mode, and a unique solution for a liquid crystal display device employing a horizontal electric field system for generating an electric field in the horizontal direction is required.
[0018]
Furthermore, the present inventor has studied the causes of light leakage of the spacer beads, and has found that the following types of events cause light leakage of the spacer beads.
[0019]
One of the phenomena is that the light leakage of each spacer bead is so large that it hinders the sinking of the dark display and worsens the black level. The degree is different from each other, and when spacer beads having a large light leakage amount among these spacer beads are locally dense, uneven brightness is induced.
[0020]
Therefore, it is a matter of course to reduce the amount of light leakage of the spacer beads, but it is important to make it exist uniformly in the plane.
[0021]
Further, in the in-plane switching mode liquid crystal display device, there is a problem that if the pretilt angle between the alignment control film and the liquid crystal is increased, the wide viewing angle characteristic of the in-plane switching mode liquid crystal display device is hindered. In particular, it has been found that when the pretilt angle exceeds 4 degrees, the viewing angle characteristic sharply narrows, and particularly for a wide viewing angle, it is preferable to set the pretilt angle to 3 degrees or less (Oe et al., Liquid Crystals, 22). Vol. 4, No.
p391, 1997).
[0022]
An object of the present invention is to provide a liquid crystal display device having a high contrast ratio in which light leakage caused by spacer beads in such a lateral electric field type normally closed type is eliminated.
[0023]
[Means for Solving the Problems]
In order to achieve the above object, a normally closed type liquid crystal display device, in particular, an active matrix type liquid crystal display device in which a horizontal electric field method is adopted and a pretilt angle between an alignment control film and liquid crystal is set to 4 degrees or less, Is controlled so that the light leakage centered on is divided into four.
[0024]
In the horizontal electric field type liquid crystal display device, the light leakage centered on the spacer is expressed by a four-split type in FIG. 1, a two-split type in FIG. 2, a three-split type or a circular type (not shown). By measuring the amount of light leakage, it was found that the four-divided spacer beads can reduce light leakage most.
[0025]
Here, a method for measuring the amount of light leakage of the spacer beads will be described. The luminance of dark display in a certain measurement area of the liquid crystal panel is measured. At this time, the luminance is measured in an area that does not include the spacer beads in the measurement area. Next, the brightness is measured by including the spacer beads in the area having the same area as the measured area, and the difference in brightness between the two is divided by the measured density of the spacer beads, thereby obtaining the light leakage amount per spacer bead. Can be estimated.
[0026]
Therefore, as a result of examining a method of preferentially expressing the four-divided shape of the spacer, it has been found that by setting the contact angle between the spacer and the liquid crystal to 60 degrees or less, the liquid crystal molecules on the spacer surface become substantially parallel alignment, which can be achieved. I understood.
[0027]
FIG. 1 is a diagram showing a cross section of one layer of a liquid crystal display device. The region 48 in FIG. 1 is the region where the stress is most applied to the liquid crystal molecules since the parallel alignment direction on the surface of the spacer beads and the alignment direction of the alignment control film are substantially 90 degrees. Therefore, in order to more stably express the region 48, it is necessary to make the wettability of the alignment control film in the direction perpendicular to the alignment control direction and the direction perpendicular thereto, that is, to give anisotropy to the contact angle and to reduce the contact angle in the alignment control direction. Is preferred.
[0028]
In particular, even in the case of a liquid crystal display device having a very low pretilt angle and a wide viewing angle, the contact angle between the liquid crystal and the spacer is larger than the contact angle between the liquid crystal and the liquid crystal. By making the contact angle smaller than the contact angle in the direction orthogonal to the above, the four-split type can be very stabilized.
[0029]
When the contact angle between the liquid crystal and the spacer beads is 90 degrees or less, the contact angle can be reduced by roughening the surface of the spacer beads. That is, if the contact angle is 90 degrees or less, the liquid crystal can fill the depressions on the surface of the spacer beads, so that a smooth surface is obtained in which a certain portion is solid on the surface of the spacer beads and a certain portion is liquid crystal. Since the contact angle between the liquid crystal and the liquid crystal is 0 degrees, the apparent contact angle decreases. Therefore, when the contact angle is 70 degrees or more and 90 degrees or less, the spacer beads made of a polymer compound can be mixed with ceramic particles, glass fibers, or the like in advance, stirred, and then separated.
[0030]
The effect of roughening the surface of the spacer beads can be expected even with an extremely fine rough surface generated when the surface layer is introduced.
[0031]
In order to make the contact angle between the spacer and the liquid crystal 60 degrees or less, specifically, a functional group serving as a wetting agent for the liquid crystal may be introduced into the surface of the spacer. As a method for introducing these functional groups, a silane coupling agent, a vinyl group or a hydroxyl group of a spacer bead body, and a chemical modification with a surface modifier having an acryl group may be used. For example, a long-chain alkyl group having a polyvalent hydroxyl group, an alkyl group having an amino group at the terminal, or the like is introduced into the surface of the spacer bead via a silane coupling agent or the like, or a polyalkyl group having an acrylic group or a vinyl group at the other terminal. A long-chain alkyl group having a valent hydroxyl group, an alkyl group having an amino group at a terminal, and the like are introduced by chemical modification. When a silane coupling agent is used, the spacer beads can be made of an inorganic material such as silica.
[0032]
Further, a functional group for improving the wettability with the spacer surface may be introduced into the liquid crystal. For a liquid crystal, an effect can be expected by introducing a functional group that reduces the surface tension. For example, fluorine groups significantly reduce their critical surface tension. Although a method for directly determining the solid surface tension has not been established yet, when the spacer is composed of a polymer compound, the contact angle is approximately 30 mN / m or more. Effective for lowering.
[0033]
Examples of the anisotropy of the contact angle between the alignment control film and the liquid crystal include an increase in rubbing strength, a molecular structure that is rigid in the alignment control direction, and a molecular structure that increases the intermolecular attractive force with the liquid crystal.
[0034]
BEST MODE FOR CARRYING OUT THE INVENTION
In the in-plane switching mode liquid crystal display device, in order to reduce the amount of light leakage, light leakage around the spacer beads is divided into four parts.
[0035]
Hereinafter, embodiments of the present invention will be described.
[0036]
(Example 1)
FIG. 3 is a schematic sectional view of a panel of the liquid crystal display device according to the present embodiment. A liquid crystal layer 30 containing a plurality of compounds is sandwiched between a pair of transparent substrates 1 and 1 '. FIG. 3 schematically shows rod-like liquid crystal molecules 6. Polarizing plates 9, 9 'are arranged on both outer sides of the pair of substrates 1, 1'. Stripe-shaped electrodes 2 and 3 are formed on a surface of one substrate 1 inside the cell, and an orientation control film 8 is further formed thereon. The electrode 2 is a common electrode that applies a voltage having a fixed waveform that does not depend on the image signal, and the electrode 3 is a pixel electrode whose waveform changes according to the image signal. The video signal electrode 10 is arranged at the same height as the pixel electrode 3. The insulating layer 4 has two layers, both of which are made of a silicon nitride film. On the other opposing substrate, a color filter 5 for performing color display is formed.
[0037]
A solution having a concentration of 3% of polyamic acid, which is a precursor of the orientation control film 8, is applied, and baked and imidized at 200 ° C. for 30 minutes. Specifically, as acid anhydrides, 1,2,3,4-cyclopentenetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 3,3 ′, 4,4 ′ Diamines such as -biscyclohexanetetracarboxylic dianhydride and 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride; 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide; A polyamic acid is prepared using 1,4-diaminocyclohexane, 3,3'-diaminodiphenylsulfone, or the like, the solution is applied to a substrate, dried and fired to form an alignment control film 8, and the liquid crystal is aligned. For rubbing. The long axis direction of the liquid crystal molecules in the obtained alignment state, that is, the initial alignment direction 11 is the angle φ defined in FIG. _LC Was set to 75 degrees. These acid anhydrides and diamine compounds do not need to be used alone, but may be used as a mixture of two or more.
[0038]
Next, polymer spacer beads 40 having a particle size of 4 μm were dispersed on the substrate by a dry spraying method. In the dry spraying method, an inert gas or the like is discharged from a compressed gas supply pipe to generate a negative pressure in the nozzle portion, and the liquid crystal display spacer beads are sucked and sprayed from the liquid crystal display spacer bead supply pipe. In this method, no solvent is used as a dispersion medium for spacer beads. The spacer beads use divinylbenzene as a constituent material, and have an alkyl group with 5 carbon atoms and a hydroxyl group introduced on the surface of the spacer beads via a silane coupling agent. Alignment control is performed so that the interaction with the liquid crystal becomes parallel. Layer 42 is provided. Thereafter, the upper and lower substrates were overlapped, and assembled in an empty cell state using a peripheral sealant. FIG. 9 shows a schematic sectional view of this liquid crystal display device. Reference numbers are the same as in FIG.
[0039]
The liquid crystal composition is a nematic liquid crystal having a positive dielectric anisotropy. The value of the dielectric anisotropy Δε is 10.2, and the refractive index anisotropy Δn is 0.073. FIG. 5 shows the switching principle of the liquid crystal molecules in the liquid crystal panel thus obtained. In this embodiment, when no electric field is applied, the liquid crystal molecules 6 have φ in the direction perpendicular to the longitudinal direction of the striped electrode. _LC = 75 degrees, but when the dielectric anisotropy of the liquid crystal is positive, 45 degrees ≦ | φ _LC | <90 degrees. The liquid crystal composition in FIG. 5 may have a negative dielectric anisotropy. In this case, the initial alignment state is set at 0 degree ≦ | φ from the vertical direction of the stripe-shaped electrode. _LC | <
It is better to orient at 45 degrees. In FIG. 5, the orientation direction 11 is indicated by an arrow. Next, as shown in FIGS. 5 (b) and 5 (d), when an electric field 13 is applied between the electrodes 2 and 3, the liquid crystal molecules 6 are oriented so that the major axis of the molecule is parallel to the direction of the electric field 13. change. At this time, θ in Expression (1) changes according to the electric field strength E, and the transmittance changes.
[0040]
In this embodiment, a liquid crystal is interposed between orthogonal polarizing plates because a birefringence mode display system is employed. Further, in order to obtain a normally-closed characteristic in which dark display is performed at a low voltage, φ defined in FIG. _P = Φ _LC = 75 degrees, that is, the polarization transmission axis 12 of one polarizing plate is made parallel to the initial alignment direction, and the polarization transmission axis 12 'of the other polarizing plate is made orthogonal. The observed transmitted light intensity is determined by equation (1).
[0041]
FIG. 6 shows an electrode group of a unit pixel portion, a common electrode 2, a pixel electrode 3, a video signal electrode 10, a scanning electrode 14, an amorphous silicon 16, a thin film transistor in this embodiment.
15, the arrangement of the insulating film 4, the orientation control film 8 is shown. FIG. 6A is a front view as viewed from a direction perpendicular to the panel surface, and FIGS. 6B and 6C are side sectional views. FIG. 7 shows a circuit system configuration in the liquid crystal display device of this embodiment. It comprises a vertical scanning signal circuit 17, a video signal circuit 18, a common electrode driving circuit 19, a power supply circuit and a controller 20, but the present invention is not limited to this configuration.
[0042]
FIG. 8 shows an example of the configuration of the optical system in the liquid crystal display device formed as described above. A backlight unit 26 including a light source 21, a light cover 22, a light guide 23, and a diffusion plate 24 is provided on a back surface of the liquid crystal panel 27. Here, the prism sheet 25 for increasing the front luminance is shown, but there is no problem if it is not provided. FIG. 10 shows an example of an exploded perspective view of the liquid crystal display device thus formed.
[0043]
The surface tension of the liquid crystal material in this example is 28 mN / m, and the contact angle with the spacer beads is 48.6 degrees. Since the contact angle of the alignment film with respect to the alignment direction is 10 degrees, light leakage caused by the spacer beads is obtained over almost the entire surface in the four-division type shown in FIG. Light leakage of one spacer bead is 8.2 × 10 ^-5 (% ・ Mm ² /).
[0044]
A method for measuring the amount of light leakage will be described. First, in a liquid crystal panel, the brightness of the dark display is measured for a certain area not including the spacer beads. Next, the luminance is measured for a region having the same area as the previously measured region and including the spacer beads. Then, the difference between the two luminances is divided by the measured density of the spacer beads, and this value is defined as the amount of light leakage per spacer bead. By measuring in this way, the amount of light leakage can be quantitatively measured.
[0045]
Note that the definition of the transmittance used here is the transmittance of the display pixel area. That is, the transmittance (luminance) of the actual liquid crystal display device is a result of being affected by light leakage due to factors other than the spacer beads, such as the aperture ratio of the color filter and the display area, and the edge portion of the pixel. Therefore, excluding these effects, the transmittance is shown in a state where only the effects of the spacer can be quantitatively evaluated.
[0046]
FIG. 11 shows the relationship between the spacer leakage density and the effect of the light leakage of the spacer of the present embodiment and the decrease in the contrast ratio given by the spacer of the comparative example described later. It can be seen that the reduction in contrast ratio was significantly suppressed. The maximum value of the spacer dispersion density is 500 pieces / mm. ² And The dispersion density required to keep the thickness of the liquid crystal layer constant depends on the margin of the liquid crystal display device manufacturing process. ² This is because such a density is not preferable because of the influence on the image quality.
[0047]
From FIG. 11, the allowable value for the light leakage of the spacer can be estimated. That is, the light leakage is 1.0 × 10 ^-4 (% ・ Mm ² /), The contrast ratio is halved only by the effect of the spacer. As described above, there are factors other than the spacers that lower the contrast ratio. Therefore, it is not preferable to further reduce the contrast ratio only by the effect of light leakage of the spacers. Therefore, in order to realize the in-plane switching mode liquid crystal display device having good image quality, which is the object of the present invention, the light leakage of the spacer must be 1.0 × 10 ^-4 (% ・ Mm ² /).
[0048]
The above configuration is based on the assumption that the diagonal is 13.3 inches, the number of pixels is 1,024 × RGB × 768, and the spacer bead dispersion density is about 120 (pieces / mm). ² ), A very good level of black display is obtained when applied to a lateral electric field type TFT liquid crystal display device. The contrast ratio becomes 300, and a high-contrast liquid crystal display device can be obtained.
[0049]
The contrast ratio is obtained by measuring the transmittance (brightness) of a bright display or the transmittance (luminance) of a brightness and a dark display, and dividing the relative value of the former by the value of the latter. The transmittance can be measured by a photomultiplier or the like when the brightness of the light source is set to 100, and the luminance can be measured by a luminance meter of the liquid crystal display device. Whichever method is used, the contrast ratio can be obtained.
[0050]
The luminance of the liquid crystal display device can be measured with a luminance meter. Whichever method is used, the contrast ratio can be obtained.
[0051]
(Example 2)
10 g of polymer spacer beads of divinylbenzene-styrene copolymer resin having a particle size of 4.0 μm are immersed in a solution of 70 g of 2% hydrochloric acid water and 30 g of isopropyl alcohol, and 3 g of 7-hydroxyoctylcarboxaldehyde is stirred under stirring. A solution dissolved in 10 g of alcohol is added dropwise. After reacting at 50 ° C. for 2 hours and filtering, the treated spacer beads are immersed in a solution of 70 g of pure water and 30 g of 30 g of isopropyl alcohol, and filtered. After repeating this operation 10 times, the filter is immersed in 70 g of toluene and filtered 5 times, and dried.
[0052]
As the monomer component of the alignment film, a mixture of 4-octadecyloxy-1,3-diaminocyclohexane and p-phenylenediamine in a molar ratio of 1: 4 as a diamine component was used, and 1,2,3,4-butane was used. A mixture of tetracarboxylic dianhydride and 1,2,3,4-cyclobutanetetracarboxylic dianhydride in an equimolar ratio is used as an acid anhydride to prepare a polyamic acid, and the solution is applied to a substrate and dried. Baking to form the alignment control film 8, and performing a rubbing treatment for aligning the liquid crystal. These acid anhydrides and diamine compounds do not need to be used alone, but may be used as a mixture of two or more.
[0053]
As in Example 1, the diagonal is 13.3 inches, the number of pixels is 1,024 × RGB × 768, and the average spacer bead dispersion density is 100 / mm. ² When applied to an in-plane switching TFT liquid crystal display device, the four-split type shown in FIG. ^-5 (% ・ Mm ² / Beads). In this embodiment, the contact angle between the liquid crystal and the spacer beads is 38.2 degrees, and the contact angle with the alignment direction of the alignment film is 8 degrees. As a result, a liquid crystal display device exhibiting a very good level of black display and having a contrast ratio of 320 can be obtained.
[0054]
(Comparative Example 1)
A polyamic acid solution of PIQ-1800 manufactured by Hitachi Chemical Co., Ltd. is applied as the orientation control film 8 at a concentration of 4%, baked at 200 ° C. for 30 minutes, and rubbed.
[0055]
Thereafter, silica spacer beads having a particle diameter of 4 μm and having a strong effect of promoting the horizontal alignment of the liquid crystal are dispersed on the substrate by a dry spraying method.
[0056]
When the liquid crystal display device is constructed in the same manner as in the first embodiment, the two-split type shown in FIG. ^-5 (% ・ Mm ² / Beads) are expressed at an abundance of about 60%. In this comparative example, the contact angle between the liquid crystal and the spacer beads was 7.8 degrees, the contact angle with the alignment direction of the alignment film was 8.9 degrees, and the contrast ratio was 200.
(Comparative Example 2)
A polyamic acid solution of PIQ-1800 manufactured by Hitachi Chemical Co., Ltd. is applied as the orientation control film 8 at a concentration of 4%, baked at 200 ° C. for 30 minutes, and rubbed.
[0057]
Polymer spacer beads having a particle diameter of 4 μm and modified so that the surface is coated with a long-chain alkyl group having 18 carbon atoms to promote vertical alignment of liquid crystal were dispersed on a substrate by a dry spraying method. After that, the upper and lower substrates are overlapped and assembled in an empty cell state using a sealing agent at the peripheral portion, and a liquid crystal display device is constructed in the same manner as in the first embodiment.
[0058]
In this case, about 70% of the light leakage around the spacer appears in the four-split type and about 30% in the two-split type. The light leakage amount of the 4-split type according to this comparative example is
42 × 10 ^-5 (% ・ Mm ² / Piece), the light leakage of the two-segment type is 94 × 10 ^-5 (% ・ Mm ² /). In this comparative example, the contact angle between the liquid crystal and the spacer beads was 83 degrees, indicating almost vertical alignment. In the case of a vertically oriented spacer bead (shown in FIGS. 1 and 2), the orientation is disturbed in the azimuthal direction with respect to the orientation direction of the orientation control film in each of the four-split type and the two-split type, and the amount of light leakage increases significantly. I do. For this reason, the floating of the black level is remarkable, and the contrast ratio becomes 150.
[0059]
(Example 3)
10 g of polymer spacer beads having a particle size of 3.8 μm are immersed in 100 g of a THF solution containing equimolar 3-aminopropyldiethoxymethylsilane, 7-hydroxyoctylcarbonyl chloride and triethylamine, and stirred at 50 ° C. for 2 hours. Then, the mixture is filtered, washed with THF, and dried.
[0060]
A polyamic acid is prepared using p-phenylenediamine as a diamine component and pyromellitic dianhydride as an acid anhydride component as a monomer component of the alignment film, and the solution is applied to a substrate, and dried and fired to be oriented. The control film 8 is formed, and a rubbing process for aligning the liquid crystal is performed. At this time, the rubbing density is adjusted so that the pretilt angle becomes 3.3 degrees.
[0061]
As in Example 1, the diagonal is 13.3 inches, the number of pixels is 1,024 × RGB × 768, and the average spacer bead dispersion density is 120 / mm. ² Is constructed. In this embodiment, the contact angle between the liquid crystal and the spacer beads is 41 degrees, and the contact angle with the alignment direction of the alignment film is 6.7 degrees. The liquid crystal display device thus configured has a four-division type shown in FIG. 1 having a light leakage contribution rate of 7.8 × 10 over almost the entire surface. ^-5 (% ・ Mm ² / Beads), a very good dark level is obtained, and a liquid crystal display device having a contrast of 295 is obtained.
[0062]
(Example 4)
10 g of polymer spacer beads having a particle size of 3.8 μm are immersed in 100 g of a THF solution containing equimolar 3-aminopropyldiethoxymethylsilane, trifluoromethoxyoctylcarbonyl chloride and triethylamine, and stirred at 50 ° C. for 2 hours. Then, the mixture is filtered, washed with THF, and dried.
[0063]
Polyamic acid was prepared by using 4,4′-diaminodiphenylmethane as a diamine component and 1,2,3,4-cyclopentanetetracarboxylic dianhydride as an acid anhydride component as a monomer component of the alignment film. The solution is applied to the substrate, dried and baked to form an alignment control film 8, and a rubbing process for aligning the liquid crystal is performed.
[0064]
As in Example 1, the diagonal is 13.3 inches, the number of pixels is 1,024 × RGB × 768, and the average spacer bead dispersion density is 90 / mm. ² Is constructed. In this embodiment, the contact angle between the liquid crystal and the spacer beads is 28.9 degrees, and the contact angle with the alignment direction of the alignment film is 9.8 degrees. The liquid crystal display device configured as described above has a four-division type shown in FIG. ^-5 (% ・ Mm ² / Beads) are expressed. As a result, a liquid crystal display device having a very good dark level and a contrast ratio of 310 can be obtained.
[0065]
(Example 5)
Diethoxy-3-glycidoxypropylmethylsilane and dihydroxyoctylamine are equimolarly mixed, stirred, and the compound obtained by evaporation is dissolved in ethanol. Polymer spacer beads having a particle size of 4.0 μm are immersed in the solution, stirred at 50 ° C. for 2 hours, filtered, washed with ethanol and dried.
[0066]
As the monomer component of the alignment film, a mixture of 4-octadecyloxy-1,3-diaminocyclohexane and p-phenylenediamine in a molar ratio of 1: 4 as a diamine component was used, and 1,2,3,4-butane was used. A mixture of tetracarboxylic dianhydride and 1,2,3,4-cyclobutanetetracarboxylic dianhydride in an equimolar ratio is used as an acid anhydride to prepare a polyamic acid, and the solution is applied to a substrate and dried. Baking to form the alignment control film 8, and performing a rubbing treatment for aligning the liquid crystal. At this time, the rubbing density is such that the pretilt angle is 2.8 degrees.
[0067]
These acid anhydrides and diamine compounds do not need to be used alone, but may be used as a mixture of two or more.
[0068]
As in Example 1, the diagonal is 13.3 inches, the number of pixels is 1,024 × RGB × 768, and the average spacer bead dispersion density is 100 / mm. ² Is constructed. In this embodiment, the contact angle between the liquid crystal and the spacer beads is 18 degrees, and the contact angle with the alignment direction of the alignment film is 9.3 degrees. In the liquid crystal display device configured as described above, the four-split type shown in FIG. ^-5 (% ・ Mm ² / Beads) are expressed. As a result, a liquid crystal display having a very good dark level and a contrast 310 can be obtained.
[0069]
(Example 6)
10 g of polymer spacer beads having a particle size of 3.8 μm are immersed in 100 g of a THF solution containing equimolar 3-aminopropyldiethoxymethylsilane, 4-hydroxypentylbenzoyl chloride and triethylamine, and stirred at 50 ° C. for 2 hours. Then, the mixture is filtered, washed with THF, and dried.
[0070]
As the monomer component of the alignment film, a mixture of 4-octadecyloxy-1,3-diaminocyclohexane and p-phenylenediamine in a molar ratio of 1: 4 as a diamine component was used, and 1,2,3,4-butane was used. A mixture of tetracarboxylic dianhydride and 1,2,3,4-cyclobutanetetracarboxylic dianhydride in an equimolar ratio is used as an acid anhydride to prepare a polyamic acid, and the solution is applied to a substrate and dried. Baking to form the alignment control film 8, and performing a rubbing treatment for aligning the liquid crystal. These acid anhydrides and diamine compounds do not need to be used alone, but may be used as a mixture of two or more.
[0071]
As in the first embodiment, the diagonal is 13.3 inches, the number of pixels is 1,024 × RGB × 768, and the average spacer dispersion density is 80 / mm. ² Is constructed. In this embodiment, the contact angle between the liquid crystal and the spacer beads is 32 degrees, and the contact angle with the alignment direction of the alignment film is 10 degrees. In the liquid crystal display device configured as described above, the four-division type shown in FIG. ^-5 (% ・ Mm ² / Beads) are expressed. As a result, a liquid crystal display having a very good black level and a contrast 290 was obtained.
[0072]
(Example 7)
Diethoxy-3-glycidoxypropylmethylsilane and dihydroxypentylamine are mixed in equimolar amounts, stirred, and the compound obtained by evaporation is dissolved in ethanol. Polymer spacer beads having a particle size of 4.0 μm are immersed in the solution, stirred at 50 ° C. for 2 hours, filtered, washed with ethanol and dried.
[0073]
As the monomer component of the alignment film, a mixture of 4-octadecyloxy-1,3-diaminocyclohexane and p-phenylenediamine in a molar ratio of 1: 4 as a diamine component was used, and 1,2,3,4-butane was used. A mixture of tetracarboxylic dianhydride and 1,2,3,4-cyclobutanetetracarboxylic dianhydride in an equimolar ratio is used as an acid anhydride to prepare a polyamic acid, and the solution is applied to a substrate and dried. -An alignment control film 8 was formed by firing, and a rubbing treatment for aligning the liquid crystal was performed. At this time, the rubbing density is such that the pretilt angle is 1 degree. These acid anhydrides and diamine compounds do not need to be used alone, but may be used as a mixture of two or more.
[0074]
As in Example 1, the diagonal is 13.3 inches, the number of pixels is 1,024 × RGB × 768, and the average spacer bead dispersion density is 100 / mm. ² Is constructed. In this embodiment, the contact angle between the liquid crystal and the spacer beads is 8 degrees, the contact angle with the alignment direction of the alignment film is 6 degrees, and the contact angle in the direction perpendicular to the alignment direction is 9.8 degrees. In the liquid crystal display configured as described above, the four-split type shown in FIG. ^-5 (% ・ Mm ² / Beads) are expressed. Thereby, a liquid crystal display device having a very good black level and a contrast ratio of 310 can be obtained.
[0075]
In this embodiment, since the pretilt angle is very small, it has a particularly wide viewing angle characteristic among the in-plane switching mode liquid crystal display devices. When the pretilt angle is low as described above, the liquid crystal molecules in the region 48 shown in FIG. This is because when the liquid crystal is horizontally oriented in the azimuth direction, it cannot be divided into four parts, and the liquid crystal cannot be horizontally oriented in the polar angle direction. At this time, if the contact angle of the orientation control film with respect to the orientation control direction is smaller than the contact angle between the liquid crystal and the spacer, it is possible to provide a property that is easily wettable with respect to the orientation control direction, and to make contact with the orientation control direction in a direction perpendicular to the direction. If the angle is larger than the contact angle between the liquid crystal and the spacer, it is difficult to wet in this direction. That is, the liquid crystal molecules are easily controlled in the alignment control direction. With this effect, even when the pretilt angle is low and the contact angle between the spacer and the liquid crystal is small, it is possible to preferentially express the four-split type. In particular, when the contact angle between the spacer and the liquid crystal is less than 10 degrees, the horizontal alignment becomes very strong. Therefore, it is preferable to use the effect of this embodiment.
[0076]
(Example 8)
10 g of polymer spacer beads having a particle size of 4.0 μm are immersed in 100 g of a THF solution containing equimolar 3-aminopropyldiethoxymethylsilane, 7-hydroxyoctylcarbonyl chloride and triethylamine, and stirred at 50 ° C. for 2 hours. Then, the mixture is filtered, washed with THF, and dried. Next, a glass fiber having a diameter of 4 μm is mixed at a ratio of 20%, dispersed in a 1: 1 solvent of 2-propanol and water for 10 minutes with an ultrasonic cleaner, and a spacer is taken out with a centrifuge. Due to this processing, minute depressions occur on the spacer surface.
[0077]
A polyamic acid is prepared using p-phenylenediamine as a diamine component and pyromellitic dianhydride as an acid anhydride component as a monomer component of the alignment film, and the solution is applied to a substrate, and dried and fired to be oriented. The control film 8 is formed, and a rubbing process for aligning the liquid crystal is performed. At this time, the rubbing density is adjusted so that the pretilt angle becomes 3.3 degrees.
[0078]
As in Example 3, the diagonal is 13.3 inches, the number of pixels is 1,024 × RGB × 768, and the average spacer bead dispersion density is 120 / mm. ² Is constructed. In this embodiment, the contact angle between the liquid crystal and the spacer beads is 20 degrees, which is lower. The contact angle of the alignment film with the alignment direction is 6.7 degrees. In the liquid crystal display device configured as described above, the four-split type shown in FIG. ^-5 (% ・ Mm ² / Beads) are expressed. As a result, a liquid crystal display having a very good black level and a contrast 305 can be obtained.
[0079]
If the contact angle between the liquid crystal and the spacer is 90 degrees or less, the liquid crystal can fill the depressions on the surface of the spacer bead, so that a smooth surface is obtained in which a certain portion is solid on the spacer bead surface and a certain portion is liquid crystal. Since the contact angle between the liquid crystals is 0 degrees, the apparent contact angle decreases. In this embodiment, the effect of reducing 41 degrees to 20 degrees is obtained for this purpose. Therefore, when the contact angle between the liquid crystal and the spacer is not less than 70 degrees and not more than 90 degrees, it is possible to mix the spacer beads made of a polymer compound with ceramic particles, glass fibers and the like in advance, stir and then separate them. Become. If the contact angle between the liquid crystal and the spacer exceeds 90 degrees, the liquid crystal cannot fill the dents on the spacer surface, so that a certain portion becomes solid on the spacer bead surface and a certain portion becomes air, increasing the apparent contact angle. Would. Therefore, a liquid crystal having a contact angle of more than 90 degrees between the liquid crystal and the spacer cannot be used.
[0080]
(Example 9)
In order to investigate the contact angle between the spacer and the liquid crystal and the contact angle between the alignment control film and the liquid crystal, a model experiment using a unit cell was performed. The unit cell is composed of a glass substrate, a polyimide alignment film made by Nissan Chemical Co., Hitachi Chemical Co., Ltd., Chisso Co., etc., and a rubbing treatment condition. The wettability in the orientation control direction and the direction perpendicular to the orientation control direction is changed, spacers are dispersed, and empty cells are assembled using a sealant. After the sealant is cured, a liquid crystal is sealed and a polarizing plate is attached to form a unit cell.
[0081]
As the liquid crystal, a liquid crystal composition manufactured by Merck, Chisso, and Roddick was used, and spacers of Examples 1 to 8 and spacers of Sekisui Chemical, Kao, and Natco Paint were used. The contact angle was measured by the above-described method, and a unit cell having a desired contact angle was prepared, and a method of measuring the amount of light leakage was employed. In a normally closed type lateral electric field type liquid crystal display device, the light leakage of the spacer can be measured at a black level in a state where no electric field is applied. Is equivalent to the value obtained by Therefore, the contrast ratio of the in-plane switching liquid crystal display device can be predicted from the method. In addition, since this method is a model experiment, an experiment using a model liquid crystal for studying the contact angle between the liquid crystal and the spacer in detail is also possible.
[0082]
Various unit cells were manufactured and examined by the above method. As a result, it was found that when the contact angle between the spacer and the liquid crystal was set to 60 degrees or less, the liquid crystal molecules on the spacer surface became substantially parallel, and the spacer having a four-divided shape could be preferentially expressed. On the other hand, when the contact angle between the spacer and the liquid crystal exceeds 80 degrees, the liquid crystal molecules on the spacer surface are vertically aligned regardless of conditions such as anchoring of the alignment control film. Light leakage increases. In the range from more than 60 degrees to 80 degrees or less, the liquid crystal molecules on the spacer surface can take either horizontal or vertical alignment depending on other factors, for example, anchoring or pretilt angle of the alignment control film. In this case, of the two phenomena, which are problems of the above-described spacer, the latter is a problem. That is, the image quality is degraded due to the presence of large and small light leakage. Another problem is that the orientation around the spacer is not stable and changes with time.
[0083]
Therefore, in order to align the liquid crystal molecules on the spacer surface in parallel, it is necessary to set the contact angle between the liquid crystal and the spacer to 60 degrees or less.
[0084]
Table 1 shows the results of this example. In this way, means for obtaining the intended high-quality horizontal electric field liquid crystal display device was obtained.
[0085]
[Table 1]

[0086]
From the above results, the following could be clarified.
[0087]
In a neutral liquid crystal having no polar group, the vertical alignment becomes strong. This is thought to be because the polar functional group exhibits an action like a wetting agent with the spacer surface. In addition, in Examples c and d, by introducing a functional group such as an alkyl group or a hydroxyl group on the surface of the spacer, the wettability can be improved, and the effect of reducing the light leakage of the spacer can be obtained. This has the effect that the functional groups on the spacer surface act as wetting agents. Therefore, it can be seen that it is effective to introduce a functional group having a function as a wetting agent for improving the wettability of the liquid crystal or the spacer surface. These effects are attributable to the difference between the intermolecular attractive force and the cohesive force of each, so that an effect can be obtained by achieving a combination that increases the attractive force between the molecules. It is not limited to the compounds of this example.
[0088]
The pretilt angle in Example f is almost 0 degrees. If the contact angle between the liquid crystal and the spacer is significantly reduced to give a strong horizontal alignment, and furthermore the contact angle between the alignment control film and the liquid crystal is also significantly reduced, the liquid crystal molecules in the region indicated by the region 48 in FIG. It can be seen that the horizontal orientation is in a stable state on the surface, and the two divisions are prioritized. Therefore, it can be seen that it is important to control the value of the contact angle between the alignment control film and the liquid crystal particularly when the contact angle between the liquid crystal and the spacer is extremely low.
[0089]
【The invention's effect】
As described above, according to the present invention, a liquid crystal display device having high contrast can be realized.
[Brief description of the drawings]
FIG. 1 is a schematic view of an orientation around a spacer in a liquid crystal display device of the present invention.
FIG. 2 is a schematic view of an orientation around a spacer in the liquid crystal display device of the present invention.
FIG. 3 is a schematic sectional view of a panel of the liquid crystal display device of the present invention.
FIG. 4 is a diagram showing angles formed by a liquid crystal molecule long axis alignment direction with respect to an electric field direction and a polarization plate polarization transmission axis.
FIG. 5 is a diagram showing an operation principle of liquid crystal in a liquid crystal display device of a horizontal electric field method.
FIG. 6 is a schematic diagram showing a plane and a cross section showing an arrangement of an electrode group, an insulating film, and an alignment control film in a unit pixel portion according to an embodiment of the present invention.
FIG. 7 is a diagram showing an example of a circuit system configuration in a liquid crystal display device of the present invention.
FIG. 8 is a diagram showing an example of an optical system configuration in a liquid crystal display device of the present invention.
FIG. 9 is a schematic sectional view of a panel of a liquid crystal display device according to one embodiment of the present invention.
FIG. 10 is an exploded configuration perspective view of the liquid crystal display device of the present invention.
FIG. 11 illustrates characteristics of the liquid crystal display device of the present invention.
[Explanation of symbols]
1, 1 '... substrate, 2 ... common electrode, 3 ... pixel electrode, 4 ... insulating layer, 5 ... color filter, 6 ... liquid crystal molecules, 8, 8' ... alignment control film provided with liquid crystal alignment ability, 9, 9 ': polarizing plate, 10: video signal electrode, 11: orientation direction of liquid crystal molecule long axis, 12: polarizing plate transmission axis direction, 13: electric field direction, 14: scanning electrode (gate wiring electrode), 15: thin film transistor, 16 ... Amorphous silicon (a-Si), 17 ... Vertical scanning signal circuit, 18 ... Video signal circuit, 19 ... Common electrode driving circuit, 20 ... Power supply circuit and controller, 21 ... Light source, 22 ... Light cover, 23 ... Light guide 24, a diffusion plate, 25, a prism sheet, 26, a backlight unit, 27, a liquid crystal panel, 29, an electrode group, 30, a liquid crystal layer, 40, a spacer, 41, a light leakage area, 42, a liquid crystal molecule alignment ability. Having surface layer 45: liquid crystal molecules that follow the alignment direction of the alignment control film, 46: liquid crystal molecules that disturb the alignment direction of the alignment control film due to the spacer bead surface and cause light leakage, 47: liquid crystal molecules that are quenched by crossed Nicols, 48 ... A region where the orientation direction of the orientation control film and the parallel orientation direction of the spacer bead surface are substantially 90 degrees, a region where the orientation direction of the orientation control film and the parallel orientation of the spacer bead surface substantially coincide.

Claims (20)

A pair of substrates at least one of which is transparent,
A liquid crystal layer disposed between the pair of substrates,
An electrode group formed on one of the pair of substrates and applying an electric field substantially parallel to the substrate surface to the liquid crystal layer, and one or more active elements connected to these electrodes;
An alignment control film formed on the pair of substrates,
Spacers distributed between the pair of substrates,
An optical means for changing optical characteristics according to the molecular orientation state of the liquid crystal layer , and a normally closed liquid crystal display device,
The pretilt and the angle between the alignment control film and the liquid crystal are 4 degrees or less,
A contact angle between the liquid crystal and the spacer is 0 degree or more and 60 degrees or less,
A liquid crystal display device, wherein a contact angle between the liquid crystal and the alignment control film with respect to an alignment control direction of the alignment control film is smaller than a contact angle with respect to a direction orthogonal to the alignment control direction. 2. The liquid crystal display device according to claim 1, wherein a pretilt and an angle between the alignment control film and the liquid crystal are 3 degrees or less. The contact angle between the liquid crystal and the spacer is larger than a contact angle of the alignment control film with respect to an alignment control direction and smaller than a contact angle of the alignment control film with respect to a direction orthogonal to the alignment control direction. Liquid crystal display device. The liquid crystal display device according to claim 1, wherein a contact angle between the liquid crystal and the spacer is less than 10 degrees. The liquid crystal display device according to claim 1, wherein a contact angle with the orientation direction of the liquid crystal and the alignment layer is less than 5 degrees 0 degrees. The liquid crystal display device according to claim 1, wherein the contact angle with respect to a direction perpendicular to the alignment control direction of the liquid crystal and the alignment layer is characterized in that at least 10 degrees. A contact angle between the liquid crystal and the spacer is less than 10 degrees,
A contact angle of the liquid crystal and the alignment control film with respect to an alignment direction is 0 degree or more and 5 degrees or less, and a contact angle of the liquid crystal and the alignment control film with respect to a direction orthogonal to the alignment control direction is 10 degrees or more. The liquid crystal display device according to claim 1, wherein The liquid crystal display device according to claim 1, wherein a surface of the spacer is roughened. 9. The liquid crystal display device according to claim 8 , wherein a functional group having hydrophilicity and a functional group having hydrophobicity are introduced into the surface of the spacer, and the spacer is roughened by the surface layer. The liquid crystal display device according to claim 9, wherein a contact angle between a material forming the spacer and the liquid crystal is less than 90 degrees. And surface tension of the liquid, represented by the above sum of the product of the cosine and the surface tension of the liquid crystal of the contact angle of the liquid crystal and the spacer, the work of adhesion of the liquid crystal and the spacer is at least 0.05 N / The liquid crystal display device according to claim 1 , wherein m is not less than m. On the surface of the spacer, the liquid crystal display device according to claim 1 or 2, characterized in that the functional group is introduced having an action as a wetting agent to the liquid crystal. 13. The liquid crystal display device according to claim 12 , wherein the functional group having a function as a wetting agent includes a hydrocarbon group and one or more hydroxyl groups. The liquid crystal display device according to claim 1 , wherein the liquid crystal contains a functional group or a compound having an action of acting as a wetting agent on the surface of the spacer. The liquid crystal display device according to claim 14, wherein the liquid crystal includes a compound having a cyano group. 3. The liquid crystal display device according to claim 1, wherein the surface tension of the liquid crystal is 25 mN / m or less. Claim wherein the liquid crystal is characterized in that it comprises a compound having a fluorine atom as a polar group
A liquid crystal display device according to item 16 . 3. The liquid crystal display device according to claim 1, wherein the light leakage centered on the spacer has a shape divided into four. When one is present the spacer to 1 square millimeters light leakage around the said spacers, according to claim 1 or 2 is ^{1.0 × 10 -4% · mm 2} / number less Liquid crystal display. 18. The liquid crystal display device according to claim 17 , wherein a functional group having a function as a wetting agent for the liquid crystal is introduced into a surface of the spacer.

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