JPH07306417A - Active matrix type liquid crystal display device - Google Patents

Abstract

PURPOSE:To obtain a device having a wide visual field angle and high opening rate by adopting a structure in which electrodes for driving liquid crystals are held by >=2 layers of upper and lower dielectric layers exclusive of the liquid crystal layer for the electrodes for driving liquid crystals and specifying the specific resistance of the liquid crystals to a specific range. CONSTITUTION:The wire-shaped electrodes l, 3, 4 are formed on the inner side of a pair of transparent substrates and orientation control films 5 are applied thereon and are subjected to an orientation treatment. A liquid crystal compsn. is clamped between a pair of the substrates. The bar-shaped liquid crystal molecules 6 are so oriented as to have some angle with the longitudinal direction of the striped electrodes 1, 3, 4 at the time of non-impression of an electric field. Changing of light transmittance by impression of the electric field 9 is made possible by arranging polarizing plates 8 at a prescribed angle 11. The structure in which the electrodes for driving liquid crystals are held by >=2 layers of the upper and lower dielectric layers exclusive of the liquid crystal layer is adopted for the electrodes for driving the liquid crystals. The specific resistance of the liquid crystals is specified to <=1X10<14> to >=1X10<9>OMEGA.cm. The opening rate is increased by specifying the specific resistance of the liquid crystals to <=1X10<14>OMEGA.cm such a manner.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active matrix type liquid crystal display device which has both a wide viewing angle and a high aperture ratio in a liquid crystal display system in which an electric field parallel to a substrate is applied.

[0002]

2. Description of the Related Art In a conventional liquid crystal display device, electrodes for driving liquid crystals are formed on the surfaces of two substrates, and electrodes facing each other are used. This is because a display system represented by a twisted nematic display system (TN system), which operates by applying an electric field in a direction perpendicular to the substrate to the liquid crystal, is adopted. In this case, a transparent electrode such as ITO (indium-tin-oxide) is used as the electrode. On the other hand, as a method for making the direction of the electric field applied to the liquid crystal substantially parallel to the substrate, a method using comb-teeth electrodes provided on one substrate is disclosed in Japanese Examined Patent Publication No. 63-21907.
It is proposed by the publication No. 4345249. In this case, the electrodes do not have to be transparent, and metal electrodes having high conductivity and opacity are used. However, in a display system in which the direction of the electric field applied to the liquid crystal using the active element is substantially parallel to the substrate (hereinafter, referred to as lateral electric field system),
There is no description about the physical properties of the liquid crystal necessary for achieving a high aperture ratio.

[0003]

In the active matrix type liquid crystal display device represented by the conventional twisted nematic system, since transparent electrodes are used as electrodes, the aperture ratio, which is the area through which light per unit pixel is transmitted, is relatively small. I was able to make it bigger. However, in the lateral electric field method, since an opaque metal electrode is used, there is a problem that the aperture ratio cannot be increased for the opaque electrode. This is a display method,
This is due to the essential problem that the opaque electrode portion cannot be used as a light transmitting region for display. The aperture ratio is a problem related to the brightness of the display device, and even if the intensity of the backlight is increased to secure the brightness, a large burden is imposed on power consumption.

Therefore, in order to obtain a high aperture ratio in the lateral electric field system, it is necessary to increase the gap between the electrodes. However, this creates new problems.
One is that the alignment disorder due to static electricity occurs. This is because the capacity of the liquid crystal is further reduced. In the horizontal electric field method, the capacitance of the liquid crystal is small because the electrode structure is generally different from that in the conventional method, but it is further reduced by widening the gap between the electrodes. Therefore, it is more likely to be affected by static electricity, and the alignment disorder due to static electricity increases. Next, when the inter-electrode gap becomes large, there is a problem that the driving voltage becomes large in the display system operated by the electric field.

The present invention relates to a horizontal electric field type active matrix type liquid crystal display device which solves these problems and has a wide viewing angle and a high aperture ratio.

[0006]

In order to solve the above problems and achieve the above object, the present invention uses the following means.
A display pixel is formed on a substrate by a scanning signal electrode, a video signal electrode, a pixel electrode and an active element, and the substrate has an alignment film of liquid crystal formed directly or through an insulating layer,
The substrate is disposed so as to face the other transparent substrate on which an alignment film of liquid crystal is formed, a liquid crystal layer is sandwiched between the two substrates, and each electrode is an electric field substantially parallel to the liquid crystal layer. , Each electrode is connected to an external control means capable of arbitrarily controlling an applied electric field according to a display pattern, and the active means is provided with a polarization means for changing optical characteristics according to the alignment state of the liquid crystal layer. A matrix type liquid crystal display device, wherein [Means 1] has a structure in which the electrodes for driving the liquid crystal are sandwiched between two or more dielectric layers other than the upper and lower liquid crystal layers, and the specific resistance of the liquid crystal is 1 × 10 ¹⁴ Ω.・ Cm or less, 1 × 10 ⁹ Ω ・ cm or more.

The display pixel includes a scanning signal electrode, a video signal electrode,
Composed of a pixel electrode and an active element on the substrate,
An alignment film of liquid crystal is formed on the substrate directly or via an insulating layer, the substrate is arranged to face the other transparent substrate on which the alignment film of liquid crystal is formed, and the liquid crystal layer is sandwiched by both the substrates. Each of the electrodes is configured so that an electric field substantially parallel to the substrate can be applied to the liquid crystal layer, and each of the electrodes is connected to an external control unit capable of arbitrarily controlling the applied electric field according to a display pattern. An active matrix type liquid crystal display device comprising a polarizing means for changing optical characteristics according to the alignment state of the liquid crystal layer, wherein [means 2] a ratio 1 / gap between electrodes and a cell gap d is 1 /
An active matrix type liquid crystal display device, wherein d is 2.0 or more and a liquid crystal having a relationship satisfying (Equation 1) between the elastic constant K _{2 of} twist and the dielectric anisotropy Δε is used.

K ₂ /Δε<9.0×10 ⁻⁸ [dyn] (Equation 1) [Means 3] In the means 2, the gap between the opposing substrates is 6 μm or less, and the gap between the electrodes is 10 μm or more. The driving voltage is 5 V or less.

[Means 4] In Means 1 and 2, represented by the general formula (I), wherein at least one cyano group, trifluoromethyl group, trifluoromethoxy group or nitro group is introduced as a terminal group into the liquid crystal. Characterized by containing a liquid crystal compound

[0010]

[Chemical 3]

(In the general formula (I), X _{1 to} X ₃ represent a fluoro group, a cyano group, a trifluoromethyl group, a trifluoromethoxy group, a nitro group or a hydrogen atom, and R represents the number of carbon atoms which may be substituted. 1 to 10 represents an alkyl group or an alkoxy group, and ring A is a cyclohexane ring, a benzene ring, a dioxane ring, a pyrimidine ring or [2,2,2
2] -bicyclooctane ring, Z represents a single bond, an ester bond, an ether bond or methylene, methyleneoxy, ethylene, and n is an integer of 1 or 2. [Means 5] In Means 1 and 2, represented by the general formula (II), wherein at least one cyano group, trifluoromethyl group, trifluoromethoxy group or nitro group is introduced into the liquid crystal in the direction of the minor axis of the molecule. The liquid crystal compound according to claim 1 is included.

[0012]

[Chemical 4]

(In the general formula (II), X ₁ and X ₂ represent a fluoro group, a cyano group, a trifluoromethyl group, a trifluoromethoxy group, a nitro group or a hydrogen atom, and R
Represents an optionally substituted alkyl or alkoxy group having 1 to 10 carbon atoms, and ring A is a cyclohexane ring, a benzene ring, a dioxane ring, a pyrimidine ring or [2,
2,2] -bicyclooctane ring, Z represents a single bond, ester bond, ether bond or methylene, methyleneoxy, ethylene, and n is an integer of 1 or 2. ) [Means 6] In Means 1 and 2, the dielectric anisotropy of the liquid crystal is positive, and the rubbing angle is 1 with respect to the direction normal to the electric field.
Is set to 20 to 20 or the liquid crystal has a negative dielectric anisotropy, and the rubbing angle is 1 to 20 with respect to the electric field direction.
It is characterized by being set to °.

[Means 7] In the means 1 and 2, the common electrode is constituted as a part of the display pixel, and an alternating current is applied to the common electrode.

[Means 8] In the means 1 and 2, the transmission axis of the polarizing plate is shifted from the initial alignment direction of the liquid crystal by 1 ° or more in the direction in which the molecular axis of the liquid crystal rotates by applying an electric field.

[0016]

The principle of the lateral electric field system is as follows. First, the angle φ _P formed by the polarization transmission axis of the polarizing plate with respect to the electric field direction, the angle φ _LC formed by the liquid crystal molecule major axis (optical axis) direction near the interface, and the phase difference plate inserted between the pair of polarizing plates. The definition of the angle φ _R formed by the fast axis of is shown in Fig. 2. Since there are a pair of polarizing plate and liquid crystal interface above and below respectively, φ _P1 ,
φ _P2, φ _LC1, referred to as φ _LC2.

1 (a) and 1 (b) are side sectional views showing the operation of the liquid crystal in the liquid crystal panel of the present invention, and FIGS. 1 (c) and 1 (d) are front views thereof. In FIG. 1, the active element is omitted. Further, in the present invention, a plurality of pixels are formed by forming a striped electrode, but only one pixel portion is shown here. FIG. 1A shows a cross section of the cell side when no voltage is applied, and FIG. 1C shows a front view at that time. Linear electrodes 1, 3, 4 are formed on the inner side of a pair of transparent substrates, and an alignment control film 5 is applied and aligned on the linear electrodes 1, 3, 4. A liquid crystal composition is sandwiched between the pair of substrates. Rod-shaped liquid crystal molecule 6
Are oriented so that they have a slight angle with respect to the longitudinal direction of the striped electrode when no electric field is applied, that is, 45 ° <| φ _LC | ≦ 90 °. The alignment directions of liquid crystal molecules on the upper and lower interfaces will be parallel here, that is, φ _LC1 = φ _LC2 will be described as an example.
The dielectric anisotropy of the liquid crystal composition is assumed to be positive. Next, when an electric field 9 is applied, the liquid crystal molecules change their directions in the direction of the electric field as shown in FIGS. 1 (b) and 1 (d). By arranging the polarizing plate 8 at a predetermined angle 11, the light transmittance can be changed by applying an electric field. As described above, according to the present invention, it is possible to provide a display with contrast even without the transparent electrode. Although the dielectric anisotropy of the liquid crystal composition is assumed to be positive,
It can be negative. In that case, the initial orientation state is oriented so as to have a slight angle | φ _LC | (that is, 0 ° <| φ _LC | ≦ 45 °) from the direction perpendicular to the longitudinal direction of the striped electrode.

In the transverse electric field method as in the above means 1, the electrodes for driving the liquid crystal are sandwiched between two or more dielectric layers above and below, and the specific resistance of the liquid crystal is 1 × 10 ¹⁴ Ω.
The aperture ratio can be increased by setting the height to be cm or less. This action will be described below. Since the lateral electric field method uses the opaque electrode as described above, there is an essential problem that the aperture ratio is inevitably smaller than that of the conventional active matrix type liquid crystal display device using the transparent electrode. Therefore, the essential solution to improve the aperture ratio in the lateral electric field method is to widen the gap between the electrodes. However, as mentioned above, new problems arise here. That is,
When the gap between the electrodes is widened, the capacitance of the liquid crystal is further reduced, and the alignment is likely to be disturbed by static electricity. Providing an auxiliary capacitance to each pixel causes a decrease in aperture ratio and cannot solve the problem. Therefore, reducing the resistance of the liquid crystal is an effective means to prevent the alignment from being disturbed by static electricity. This also improves the domain around the spacer beads. In the conventional active matrix liquid crystal display device, in order to apply a sufficient voltage to the liquid crystal even in the non-selection period, at least 1 × 10 ¹³ Ω · c
A liquid crystal having a high specific resistance value of m or more, preferably 1 × 10 ¹⁴ Ω · cm or more has to be used. In the horizontal electric field method, a dielectric other than liquid crystal, such as glass or an insulating film, functions as a storage capacitor that secures a voltage holding ratio that is necessary for actual driving. According to the experiment, as shown in FIG. 8, 1 × 10 ¹⁰
It has been confirmed that even a liquid crystal of Ω · cm exhibits a high voltage holding ratio of 90% or more (frame frequency: 60 Hz). However, as compared with the conventional method such as the TN method, the total capacity including the capacity of the liquid crystal and the storage capacity in the lateral electric field method is smaller, and is easily affected by static electricity.

Widening the gap between the electrodes to achieve a high aperture ratio causes not only the problem of static electricity but also an increase in drive voltage. Therefore, as in the means 2 and 3, between the dielectric anisotropy (Δε) of the liquid crystal composition layer and the elastic constant (K ₂ ) of the twist, K ₂ /Δε<9.0×10 ⁻⁸ [dyn] We have found that it is effective to satisfy the relationship. In the normal lateral electric field method, the thickness of the electrode is smaller than that of the liquid crystal layer, so that it is impossible to give the liquid crystal layer an electric field completely parallel to the interface between the liquid crystal and the alignment film. This incomplete lateral electric field reduces the efficiency of in-plane switching of the liquid crystal. Therefore, by making the permittivity ε _{LC of the} liquid crystal larger than the permittivity ε _{AF of the} alignment film, preferably twice as large as ε _AF , a lateral electric field more parallel to the interface between the liquid crystal and the alignment film can be obtained. Can be given to the liquid crystal. Therefore, the lateral electric field required for the liquid crystal to switch in the plane is efficiently applied to the liquid crystal. Then, as a result of diligent studies by reducing the elastic constant K _{2 of the} twist or increasing the dielectric anisotropy of the liquid crystal, the ratio of the two is 9.0 × 10 ⁻⁸ [dyn] or less, preferably the both. It has been found that when the ratio is 7.0 × 10 ⁻⁸ [dyn] or less, driving at 5 V or less is possible. The driving voltage of 5V as used herein means that display can be performed using the 5V withstand voltage of the signal voltage driver.

Further, the liquid crystal compound represented by the general formula (I) in which at least one cyano group, trifluoromethyl group, trifluoromethoxy group or nitro group is introduced as an end group into the liquid crystal as in the means 4. It has been found that the inclusion of is effective means for obtaining a liquid crystal display device having a high aperture ratio. That is, by reducing the specific resistance, static electricity is prevented, and the effect of reducing the driving voltage is also exerted. It is also effective for lowering the viscosity required for high-speed response. Liquid crystals that cannot have a large specific resistance such as cyano groups can be used because the horizontal electric field method has a high voltage holding ratio even if the specific resistance of the liquid crystal is small, so the number of types of liquid crystals that can be used has greatly increased. by.

[0021]

[Chemical 5]

(In the general formula (I), X _{1 to} X ₃ represent a fluoro group, a cyano group, a trifluoromethyl group, a trifluoromethoxy group, a nitro group or a hydrogen atom, and R represents the number of carbon atoms which may be substituted. 1 to 10 represents an alkyl group or an alkoxy group, and ring A is a cyclohexane ring, a benzene ring, a dioxane ring, a pyrimidine ring or [2,2,2
2] -bicyclooctane ring, Z represents a single bond, an ester bond, an ether bond or methylene or ethylene, and n is an integer of 1 or 2. )In particular,
1,2-Dicyano-4- [trans-4- (trans-
4-propylcyclohexyl) cyclohexyl] benzene, trans-4-propyl- (3,4-dicyanobiphenyl-4'-yl) cyclohexane, 2- (trans-4-propylcyclohexyl) -1- [trans-4
-(3,4-Dicyanophenyl) cyclohexyl] ethane, 3,4-dicyanophenyl-trans-4-pentylcyclohexylcarboxylate, 4-cyano-3-
Fluorophenyl-trans-4-propylcyclohexylcarboxylate, trans-4-heptyl-
(3,5-Difluoro-4-nitrophenyl) cyclohexane, 2,6-difluoro-1-cyano-4- [trans-4- (trans-4-propylcyclohexyl)
Cyclohexyl] benzene, trans-4-propyl-
(3,4,5-trifluorobiphenyl-4'-yl)
Cyclohexane, 2- (trans-4-propylcyclohexyl) -1- [trans-4- (3,5-difluoro-4-nitrophenyl) cyclohexyl] ethane,
3,5-difluoro-4-nitrophenyl-trans-
4-pentylcyclohexylcarboxylate, trans-4-heptyl- (3-fluoro-4-cyanophenyl) cyclohexane, 2-fluoro-1-nitro-4-
[Trans-4- (trans-4-propylcyclohexyl) cyclohexyl] benzene, trans-4-propyl- (3-fluoro-4-cyanobiphenyl-4'-
Yl) cyclohexane, 2- (trans-4-propylcyclohexyl) -1- [trans-4- (3-fluoro-4-nitrophenyl) cyclohexyl] ethane, 3
-Fluoro-4-cyanophenyl-trans-4-pentylcyclohexylcarboxylate, trans-4-
Heptyl- (4-cyanophenyl) cyclohexane, 4
-Cyanophenyl-5-pentyl-1,3-pyrimidine, 4-cyano-3-fluorophenyl-5-propyl-1,3-pyrimidine, 4-cyanophenyl-4-pentyl-1,3-dioxane, 4- Cyanophenyl-4-
Examples include pentyl- [2,2,2] -bicyclooctane. However, it is not limited to these compounds. 4-cyano-3-fluorophenyl-trans-4
It is known that a liquid crystal compound having a fluoro group at the ortho position at the cyano terminal represented by -propylcyclohexylcarboxylate is unlikely to form a dimer that cancels the dipole moment. Since the ratio is large, it is effective for low voltage driving of the horizontal electric field method. Further, when using a liquid crystal having a negative dielectric anisotropy, means 5
As described above, a liquid crystal compound represented by the general formula (II), in which at least one cyano group, trifluoromethyl group, trifluoromethoxy group or nitro group is introduced into the liquid crystal in the minor axis direction of the molecule, is included. Have been found to be an effective means for obtaining a liquid crystal display device having a high aperture ratio. That is, by reducing the specific resistance, static electricity is prevented, and the effect of reducing the driving voltage is also exerted. It is also effective for lowering the viscosity required for high-speed response. Liquid crystals that cannot have a large specific resistance such as cyano groups can be used because the horizontal electric field method has a high voltage holding ratio even if the specific resistance of the liquid crystal is small, so the number of types of liquid crystals that can be used has greatly increased. by.

[0023]

[Chemical 6]

(In the general formula (II), X ₁ and X ₂ represent a fluoro group, a trifluoromethyl group, a trifluoromethoxy group, a cyano group, a nitro group or a hydrogen atom, and R 1
Represents an optionally substituted alkyl or alkoxy group having 1 to 10 carbon atoms, and ring A is a cyclohexane ring, a benzene ring, a dioxane ring, a pyrimidine ring or [2,
2,2] -bicyclooctane ring, Z represents a single bond, an ester bond, an ether bond or methylene or ethylene, and n is an integer of 1 or 2. )In particular,
Trans-4-heptyl- (2-cyano-3-fluorophenyl) cyclohexane, 2-cyano-3-fluoro-4- [trans-4- (trans-4-propylcyclohexyl) cyclohexyl] benzene, trans-4
-Propyl- (2-cyano-3-fluorobiphenyl-
4'-yl) cyclohexane, 2- (trans-4-propylcyclohexyl) -1- [trans-4- (2-
Cyano-3-fluorophenyl) cyclohexyl] ethane, 2-cyano-3-fluorophenyl-trans-4
-Pentylcyclohexylcarboxylate, trans-4-heptyl- (2-fluoro-3-nitrophenyl) cyclohexane, 2-fluoro-3-cyano-4-
[Trans-4- (trans-4-propylcyclohexyl) cyclohexyl] benzene, trans-4-propyl- (2-fluoro-3-nitrobiphenyl-4'-
Yl) cyclohexane, 2- (trans-4-propylcyclohexyl) -1- [trans-4- (2-fluoro-3-nitrophenyl) cyclohexyl] ethane, 2
-Fluoro-3-cyanophenyl-trans-4-pentylcyclohexylcarboxylate, 2,3-dicyanophenyl-5-pentyl-1,3-pyrimidine, 2-
Cyano-3-fluorophenyl-5-propyl-1,3
-Pyrimidine, 2,3-dicyanophenyl-4-pentyl-1,3-dioxane, 2-cyano-3-fluorophenyl-4-pentyl- [2,2,2] -bicyclooctane and the like. However, it is not limited to these compounds.

On the other hand, as another means for lowering the drive voltage, when the dielectric anisotropy of the liquid crystal is positive as in the means 6, the rubbing angle is 1 ° to 20 with respect to the normal direction of the electric field.
When the liquid crystal has a negative dielectric anisotropy, setting the rubbing angle to 1 ° to 20 ° with respect to the electric field direction is an important means for reducing the driving voltage. Desirably, when the angle is 15 ° or less, the effect is great. That is, the voltage at the maximum transmittance shifts to the lower voltage side as the angle formed by the direction of the electric field of the liquid crystal molecules and the direction of the electric field approaches 90 °. Moreover, since the threshold voltage of the response to the electric field shifts to the high voltage side, the non-selection voltage can be set to the high voltage side. Therefore, the drive voltage width can be reduced. FIG. 9 shows a typical example thereof. At this time, the rubbing angle is preferably as small as possible so that no domain is generated.

In addition, after applying such means, by combining with the technique of applying an alternating current to the common electrode and performing a voltage difference between the signal voltage and the common electrode voltage as in the means 7,
The drive voltage can be further reduced.

Further, shifting the axis of the polarizing plate by 1 ° or more with respect to the initial alignment direction of the liquid crystal as in the above means 8 is also an effective means for reducing the drive voltage width as shown in FIG. I found that.

[0028]

EXAMPLES The present invention will be specifically described with reference to examples.

[Embodiment 1] Two transparent glass substrates having a thickness of 1.1 mm and having a polished surface are used as substrates. A thin film transistor was formed on one of these substrates, and an alignment film serving also as an insulating film was formed on the outermost surface thereof. In this embodiment, polyimide is used as the alignment film,
A rubbing treatment for aligning the liquid crystal was performed thereon.
Polyimide was applied on the other substrate and the same rubbing treatment was performed. The rubbing directions on the upper and lower interfaces are substantially parallel to each other, and the angle with the direction of the applied electric field is 75 ° (φ _LC1 =
φ _LC2 = 75 °). Between these substrates, the dielectric anisotropy Δε is positive and its value is 7.3, and the refractive index anisotropy Δn is
A nematic liquid crystal composition of 0.074 (589 nm, 20 ° C.) was sandwiched. The gap d was 4.0 μm when spherical polymer beads were dispersed and sandwiched between the substrates and the liquid crystal was enclosed. Therefore, Δn · d is 0.296 μm. The panel was sandwiched between two polarizing plates [G1220DU manufactured by Nitto Denko Corporation], and the polarization transmission axis of one polarizing plate was set to φ _P1 = 75 °, and the other was set to be orthogonal thereto, that is, φ _P2 = −15 °. . In this embodiment, a normally closed characteristic is adopted in which a dark state is obtained at a low voltage (V _OFF ) and a bright state is obtained at a high voltage (V _ON ).

The structures of the thin film transistor and various electrodes are shown in FIG. FIG. 3 shows a front view seen from the direction perpendicular to the substrate surface and a side sectional view taken along the lines AA 'and BB' of the front view. The thin film transistor element 14 is composed of a pixel electrode (source electrode) 4, a signal electrode (drain electrode) 3, a scan electrode (gate electrode) 12, and amorphous silicon 13. The common electrode (common electrode) 1 and the scanning electrode 12, and the signal electrode 3 and the pixel electrode 4 are formed by patterning the same metal layer. The capacitive element 16 is formed as a structure in which the insulating film 2 is sandwiched between the pixel electrode 4 and the common electrode 1 in the region where the two common electrodes 1 are coupled to each other. Pixel electrode 4
Is arranged between two common electrodes 1 in the front view. Pixel pitch is horizontal (that is, between signal wiring electrodes)
Is 69 μm, and the vertical direction (that is, between scanning wiring electrodes) is 20
It is 7 μm. The electrode width is a scanning electrode 12, which is a wiring electrode extending over a plurality of pixels, a signal electrode 3, a common electrode wiring portion (a portion extending in parallel to the scanning wiring electrode (horizontal direction in FIG. 3)).
Was widened to avoid line defects. Each width is 10 μm
Is. On the other hand, in order to improve the aperture ratio, the width of the pixel electrode 4 formed independently for each pixel and the portion of the common electrode 1 extending in the longitudinal direction of the signal wiring electrode is slightly narrowed to 5 μm.
m and 8 μm. By narrowing the width of these electrodes, the possibility of disconnection due to the inclusion of foreign matter or the like increases, but in this case, a partial defect of one pixel does not lead to a line defect. In addition, the common electrode and the signal electrode were slightly (1 μm) overlapped with each other with the insulating film 2 interposed therebetween in order to achieve the highest possible aperture ratio. As a result, the black matrix in the direction parallel to the signal wiring becomes unnecessary. Therefore, as shown in FIG. 3, a black matrix structure that shields light only in the direction of the scanning wiring electrodes is adopted. The black matrix 22 may be provided on the substrate provided with the electrode group as shown in FIG. 3 or may be provided on the opposite substrate. Thus, the gap between the common electrode and the pixel electrode is 20 μm, and the length of the opening in the longitudinal direction is 157 μm.
m, and a high aperture ratio of 44.0% was obtained. The number of pixels was 320 × 160 with 320 signal wiring electrodes and 160 wiring electrodes.

By the way, the specific resistance of liquid crystal is 7.6 × 10 ^12.
Ω · cm, and there was no alignment failure due to static electricity at this time. In this way, an active matrix type liquid crystal display device having a wide viewing angle and a high aperture ratio, which does not cause grayscale inversion in the vertical and horizontal directions of 60 ° or more, was obtained.

[Embodiment 2] This embodiment has the same configuration as that of Embodiment 1 except for the following.

The liquid crystal used in Example 1 is 4-cyano-3.
-Fluorophenyl-trans-4-propylcyclohexylcarboxylate was used by adding 5% by weight of the total liquid crystal weight.

The specific resistance of the liquid crystal at this time is 1.3 × 10 ¹¹
It was Ω · cm, and there was no alignment failure due to static electricity. In this way, an active matrix type liquid crystal display device having a wide viewing angle and a high aperture ratio, which does not cause grayscale inversion in the vertical and horizontal directions of 60 ° or more, was obtained.

[Third Embodiment] This embodiment has the same configuration as that of the first embodiment except for the following.

As the liquid crystal, the liquid crystal of Example 1 to which 3,4-dicyanophenyl-trans-4-pentylcyclohexylcarboxylate was added by 7% by weight based on the total weight of the liquid crystal was used.

The specific resistance of the liquid crystal at this time is 3.3 × 10 ¹¹
It was Ω · cm, and there was no alignment failure due to static electricity. In this way, an active matrix type liquid crystal display device having a wide viewing angle and a high aperture ratio, which does not cause grayscale inversion in the vertical and horizontal directions of 60 ° or more, was obtained.

[Embodiment 4] This embodiment has the same configuration as that of Embodiment 1 except for the following.

The liquid crystals are 4-cyano-3-fluorophenyl-trans-4-ethylphenylcarboxylate, 1
-[4- (3,4,5-trifluorophenyl) cyclohexyl] -2- (4-methylcyclohexyl) ethane, 4-cyano-3-fluorophenyl-4- (4-propylcyclohexyl) phenylcarboxylate, etc. In addition to the main component, 4-trifluoromethoxy-3,5-difluorophenyl-trans-4-pentylcyclohexylcarboxylate was added in an amount of 1% by weight of the total liquid crystal.
The thing added 0 weight% was used.

The specific resistance of the liquid crystal at this time is 2.4 × 10 ^10.
It was Ω · cm, and there was no alignment failure due to static electricity. Also, the ratio of twist elastic constant K ₂ and dielectric anisotropy Δε K ₂ /
Δε is 8.5 × 10 ^-8 Ω · cm and driving voltage is 5V
I was able to: In this way up, down, left and right 60
An active matrix type liquid crystal display device having a wide viewing angle and a high aperture ratio, which does not cause gradation inversion more than °, was obtained.

[Embodiment 5] This embodiment has the same configuration as that of Embodiment 1 except for the following.

The liquid crystals are 4-cyano-3-fluorophenyl-trans-4-ethylphenylcarboxylate, 1
-[4- (3,4,5-Trifluorophenyl) cyclohexyl] -2- (4-methylcyclohexyl) ethane, 4-cyano-3-trifluoromethyl-5-fluorophenyl-4- (4-propylcyclohexyl) ) In addition to phenylcarboxylate as a main component, 4-cyano-3,5-difluorophenyl-trans-4-pentylcyclohexylcarboxylate was added in an amount of 20% by weight based on the total weight of liquid crystal.

The specific resistance of the liquid crystal at this time is 9.3 × 10 ⁹ Ω.
・ It was cm, and there was no orientation failure due to static electricity. In addition, the ratio of twist elastic constant K ₂ and dielectric anisotropy Δε K ₂ / Δ
ε was 5.4 × 10 ⁻⁸ Ω · cm, and the driving voltage could be 5 V or less. In this way, an active matrix type liquid crystal display device having a wide viewing angle and a high aperture ratio, which does not cause grayscale inversion in the vertical and horizontal directions of 60 ° or more, was obtained.

[Sixth Embodiment] This embodiment has the same configuration as that of the first embodiment except for the following.

The structures of the thin film transistor and various electrodes are shown in FIG. FIG. 4 shows a front view seen from a direction perpendicular to the substrate surface and a side sectional view taken along the lines AA ′ and BB ′ of the front view. The thin film transistor element 14 is composed of a pixel electrode (source electrode) 4, a signal electrode (drain electrode) 3, a scan electrode (gate electrode) 12, and amorphous silicon 13. The common electrode 1 and the scan electrode 12, and the signal electrode 3 and the pixel electrode 4 are formed by patterning the same metal layer. The capacitive element 16 is formed as a structure in which the insulating protective film 2 is sandwiched between the pixel electrode 4 and the common electrode 1 in the region where the two common electrodes 1 are coupled. The pixel electrode is disposed between the three common electrodes 1 in the front view. The pixel pitch is 100 μm in the lateral direction (that is, between the signal wiring electrodes),
The vertical direction (that is, between the scanning wiring electrodes) is 300 μm. As for the electrode width, the scanning electrode 12, the signal electrode 3, the common electrode wiring portion (the portion extending in parallel to the scanning wiring electrode (horizontal direction in FIG. 3)) which is a wiring electrode extending over a plurality of pixels is widened,
Avoided line defects. Width is 10μm, 8μm, 8 respectively
μm. On the other hand, the widths of the pixel electrode 4 formed independently for each pixel and the portion of the common electrode 1 extending in the longitudinal direction of the signal wiring electrode are slightly narrowed to 5 μm and 6 μm, respectively. By narrowing the width of these electrodes, the possibility of disconnection due to the inclusion of foreign matter or the like increases, but in this case, a partial defect of one pixel does not lead to a line defect. A gap of 2 μm was provided between the signal electrode 3 and the common electrode 1 with an insulating film 25 interposed therebetween. The black matrix has a structure as shown in FIG. 5 together with a color filter on the counter substrate side. In this way, the gap between the common electrode 1 and the pixel electrode 4 was 15 μm, the length of the opening in the longitudinal direction was 250 μm, and a high aperture ratio of 50% was obtained. The number of pixels was 640 × 480 with 640 signal wiring electrodes and 480 wiring electrodes.

Between the substrates, the dielectric anisotropy Δε is positive and its value is 8.9, and the refractive index anisotropy Δn is 0.08 (589n).
m, 20 ° C.), 4-cyano-3-fluorophenyl-
Trans-4-ethylphenylcarboxylate, 1-
[4- (3,4,5-trifluorophenyl) cyclohexyl] -2- (4-methylcyclohexyl) ethane,
A nematic liquid crystal composition containing 4-cyano-3-fluorophenyl-4- (4-propylcyclohexyl) phenylcarboxylate as a component was sandwiched.

The specific resistance of the liquid crystal at this time is 8.1 × 10 ^10.
It was Ω · cm, and there was no alignment failure due to static electricity. In this way, an active matrix type liquid crystal display device having a wide viewing angle and a high aperture ratio in which gray scale inversion of 60 degrees or more in vertical and horizontal directions does not occur was obtained.

[Embodiment 7] This embodiment has the same configuration as that of Embodiment 6 except for the following.

The liquid crystal used in Example 6 was 3, 4
-Dicyano-5-fluorophenyl-trans-4-propylcyclohexylcarboxylate was added at 10% by weight of the total weight of the liquid crystal.

The specific resistance of the liquid crystal at this time is 2.2 × 10 ^10.
It was Ω · cm, and there was no alignment failure due to static electricity. Also, the ratio of twist elastic constant K ₂ and dielectric anisotropy Δε K ₂ /
Δε is 4.6 × 10 ^-8 Ω · cm and driving voltage is 5V
I was able to: In this way up, down, left and right 60
An active matrix type liquid crystal display device having a wide viewing angle and a high aperture ratio, which does not cause gradation inversion more than °, was obtained.

[Embodiment 8] This embodiment has the same configuration as that of Embodiment 6 except for the following.

The liquid crystals used in Example 6 were 3, 4
-Dicyano-5-fluorophenyl-trans-4-propylcyclohexylcarboxylate was added at 20% by weight of the total weight of the liquid crystal.

The specific resistance of the liquid crystal at this time is 6.2 × 10 ⁹
It was Ω · cm, and there was no alignment failure due to static electricity. In addition, the ratio of twist elastic constant K ₂ and dielectric anisotropy Δε K ₂ / Δ
ε was 2.9 × 10 ⁻⁸ Ω · cm, and the driving voltage could be 5 V or less. In this way up / down / left / right 60 °
As described above, an active matrix type liquid crystal display device having a wide viewing angle and a high aperture ratio without grayscale inversion is obtained.

[Embodiment 9] This embodiment has the same configuration as that of Embodiment 6 except for the following.

The liquid crystal used in Example 6 was added with 3-cyano-4-trifluoromethoxy-5-fluorophenyl-trans-4-ethylcyclohexylcarboxylate in an amount of 10% by weight based on the total weight of the liquid crystal.

The specific resistance of the liquid crystal at this time is 8.8 × 10 ⁹ Ω.
・ It was cm, and there was no orientation failure due to static electricity. Also, the ratio of twist elastic constant K ₂ and dielectric anisotropy Δε K ₂ /
Δε is 2.3 × 10 ^-8 Ω · cm and driving voltage is 5V
I was able to: In this way up, down, left and right 60
An active matrix type liquid crystal display device having a wide viewing angle and a high aperture ratio, which does not cause gradation inversion more than °, was obtained.

[Embodiment 10] This embodiment has the same configuration as that of Embodiment 1 except for the following.

The rubbing directions of the alignment films on the upper and lower substrates are substantially parallel to each other, and the angle with the direction of the applied electric field is 15 °.
(Φ _LC1 = φ _LC2 = 15 °). A nematic liquid crystal composition having a negative dielectric anisotropy Δε and a value of −3.3 between these substrates and a refractive index anisotropy Δn of 0.074 (589 nm, 20 ° C.) has 3-cyano-. A liquid crystal in which 2-fluorophenyl-trans-4-pentylcyclohexylcarboxylate was added at 4% by weight of the total weight of the liquid crystal was sandwiched.

The specific resistance of the liquid crystal at this time is 8.6 × 10 ¹¹
It was Ω · cm, and there was no alignment failure due to static electricity. In this way, an active matrix type liquid crystal display device having a wide viewing angle and a high aperture ratio, which does not cause grayscale inversion in the vertical and horizontal directions of 60 ° or more, was obtained.

[Embodiment 11] This embodiment has the same configuration as that of Embodiment 6 except for the following.

The liquid crystal has a negative dielectric anisotropy Δε and a value of −3.3, and a refractive index anisotropy Δn of 0.074 (589).
2- (trans-4-propylcyclohexyl) -1- [trans-
4- (2,3-Dicyanophenyl) cyclohexyl] ethane was added at 10% by weight of the total weight of the liquid crystal.

The specific resistance of the liquid crystal at this time is 7.2 × 10 ^10.
It was Ω · cm, and there was no alignment failure due to static electricity. In this way, an active matrix type liquid crystal display device having a wide viewing angle and a high aperture ratio, which does not cause grayscale inversion in the vertical and horizontal directions of 60 ° or more, was obtained.

[Embodiment 12] This embodiment has the same configuration as that of Embodiment 6 except for the following.

The rubbing directions of the alignment films on the upper and lower substrates are substantially parallel to each other, and the angle with the direction of the applied electric field is 85 °.
(Φ _LC1 = φ _LC2 = 85 °). On the other hand, the polarization transmission axis of the polarizing plate was set to φ _P1 = 85 °, and the other polarizing plate was orthogonal to that, that is, φ _P2 = −5 °. In this embodiment, a normally closed characteristic is adopted in which a dark state is obtained at a low voltage (V _OFF ) and a bright state is obtained at a high voltage (V _ON ).

[0065] Voltage of the active matrix type liquid crystal display device this time - transmittance characteristic is as shown in FIG. 11, V _OFF
Could be set to 2.1V and V _ON to 6.8V. Therefore,
The driving voltage range could be 4.7V. In this way, an active matrix type liquid crystal display device having a wide viewing angle and a high aperture ratio, which does not cause grayscale inversion in the vertical and horizontal directions of 60 ° or more, was obtained.

[Embodiment 13] This embodiment has the same structure as Embodiment 11 except for the following.

The rubbing directions of the alignment films on the upper and lower substrates are substantially parallel to each other, and the angle with the direction of the applied electric field is 5 °.
(Φ _LC1 = φ _LC2 = 5 °). On the other hand, the polarization transmission axis of the polarizing plate was set to φ _P1 = 5 °, and the other polarizing plate was set to be orthogonal thereto, that is, φ _P2 = −85 °. In this embodiment, a normally closed characteristic is adopted in which a dark state is obtained at a low voltage (V _OFF ) and a bright state is obtained at a high voltage (V _ON ).

At this time, V _OFF could be set to 4.0 V and V _ON to 8.8 V based on the voltage-transmittance characteristics of the active matrix type liquid crystal display device, and the driving voltage width could be set to 4.8 V. In this way, an active matrix type liquid crystal display device having a wide viewing angle and a high aperture ratio, which does not cause grayscale inversion in the vertical and horizontal directions of 60 ° or more, was obtained.

[Embodiment 14] This embodiment has the same structure as Embodiment 12 except for the following.

In order to apply an alternating current to the common electrode, the structure shown in FIG. 6 was adopted. A scanning electrode driving circuit 18 and a signal electrode driving circuit 19 are connected to each scanning wiring 12 and each signal wiring 3. The common electrode driving circuit 20 was also connected to the common electrode 1. A signal waveform having information is applied to the signal electrode 3, and a scanning waveform is applied to the scanning electrode 12 in synchronization with the signal waveform. An information signal is transmitted from the signal electrode 3 to the pixel electrode 4 via the thin film transistor 14, and a voltage is applied to the liquid crystal portion between the signal electrode 3 and the common electrode 1. In the present invention, a voltage waveform is also applied to the common electrode, and a voltage higher than that is applied to the liquid crystal layer. FIG. 7 shows the waveform of the voltage applied to each wiring electrode. The amplitude of the voltage waveform is V _D-CENTER = 14.0V, V _GH = 28.0V, V _GL =
0V, V _DH = 16.4V, V _DL = 11.4V, V _CH = 1
The settings were 5.1 V and V _CL = 9.1 V. V _ON and V _OFF shown in FIG. 11 were 2.1 V and 6.8 V, respectively, and a sufficiently high contrast ratio 150 was obtained. V in FIG.
_DP-P , V _SP-P and V _CP-P / ₂ are signal voltage, source voltage,
Represents the peak to peak of the common voltage.

In the present embodiment, the amplitude V _DP-P (≡V _DH -V _DL ) of the drive voltage waveform supplied to the signal wiring electrode can be driven at a very low value of only 4.7 V, which is an inexpensive drive. A driver can be used, and cost reduction can be realized.

[Embodiment 15] This embodiment has the same configuration as that of Embodiment 13 except for the following.

In the same manner as in Example 14, driving was performed by applying an alternating current to the common electrode. As a result, an inexpensive drive driver can be used and the cost can be reduced.

[Embodiment 16] This embodiment has the same configuration as that of Embodiment 14 except for the following.

The transmission axis of the polarizing plate was deviated from the rubbing direction by 10 ° in the direction in which the molecular axis of the liquid crystal was rotated by applying an electric field. That is, φ _P1 = 75 ° and φ _P2 = −15 ° were set. FIG. 12 shows the relationship between the voltage-transmittance characteristic obtained at this time and the drive waveform. In addition, V _DP-P , V _SP-P and V _CP-P
/ ₂ is the peak topea of signal voltage, source voltage, common voltage
Represent k respectively.

Since an alternating current is applied to the common electrode, the following structure is adopted as in the ninth embodiment. A scanning electrode driving circuit 18 is provided on each scanning wiring 12 and each signal wiring 3.
And the signal electrode driving circuit 19 was connected. The common electrode driving circuit 20 was also connected to the common electrode 1 (FIG. 6). A signal waveform having information is applied to the signal electrode 3, and a scanning waveform is applied to the scanning electrode 12 in synchronization with the signal waveform. An information signal is transmitted from the signal electrode 3 to the pixel electrode 4 via the thin film transistor 14, and a voltage is applied to the liquid crystal portion between the signal electrode 3 and the common electrode 1. In the present invention, a voltage waveform is also applied to the common electrode, and a voltage higher than that is applied to the liquid crystal layer. FIG. 7 shows the waveform of the voltage applied to each wiring electrode. The amplitude of the voltage waveform is V _D-CENTER = 14.0
V, V _GH = 28.0V, V _GL = 0V, V _DH = 15.1V, V
_DL = 12.9V, V _CH = 20.4V, V _CL = 4.39V, and as a result, the jump voltage ΔV _GS (+), ΔV _GS (-) due to the parasitic capacitance between the gate electrode and the source electrode. Table 1 shows the voltage V _S applied to the pixel electrode and the voltage V _LC applied to the liquid crystal. The unit of voltage will be all volts hereinafter.

[0077]

[Table 1]

V _ON and V _OFF shown in FIG. 12 are 9.
It was 16 V and 6.85 V, and a sufficiently high contrast ratio of 100 was obtained.

In this example, the amplitude V _DP-P (≡V _DH -V _DL ) of the drive voltage waveform supplied to the signal wiring electrode could be driven at a very low value of only 2.2V.

[Embodiment 17] This embodiment has the same configuration as that of Embodiment 15 except for the following.

In the same manner as in Example 16, the transmission axis of the polarizing plate was shifted by 10 ° from the rubbing direction in the direction in which the molecular axis of the liquid crystal was rotated by applying an electric field. That is, φ _P1 = 15 °,
φ _P2 = -75 ° was set. As a result, V _ON and V _OFF were 17.4 V and 14.2 V, respectively, and a sufficiently high contrast ratio of 100 was obtained.

In this example, the amplitude V _DP-P (≡V _DH -V _DL ) of the drive voltage waveform supplied to the signal wiring electrode could be driven at a very low value of 3.2 V.

The liquid crystal compositions and liquid crystal compounds described in the examples are some specific examples and are not limited to those described. Further, the pixel structure and configuration of the display device are not limited to those described in the embodiments.

[0084]

According to the present invention, by using a liquid crystal having a lower purity and a lower specific resistance than the liquid crystal used in the conventional active matrix type liquid crystal display device, an active matrix which achieves both a wide viewing angle and a high aperture ratio. Type liquid crystal display device can be obtained. Further, the ratio K ₂ / Δε between the twist elastic constant K ₂ and the dielectric anisotropy Δε is 9.0 × 10 ⁻⁸ [dyn].
By using the following liquid crystals, the effect of achieving both a wide viewing angle and a high aperture ratio can be further enhanced.

[Brief description of drawings]

FIG. 1 is a diagram showing an operation of a liquid crystal in a horizontal electric field system of the present invention.

FIG. 2 is a diagram showing definitions of a rubbing direction and an axial direction of a polarizing plate.

FIG. 3 is a diagram showing an example of an electrode structure in a unit pixel in the liquid crystal display device of the present invention.

FIG. 4 is a diagram showing another example of an electrode structure in a unit pixel in the liquid crystal display device of the present invention.

FIG. 5 is a diagram showing a typical example of the configuration of a color filter substrate.

FIG. 6 is a diagram showing a TFT circuit system in a liquid crystal display device of the present invention.

FIG. 7 is a diagram showing an example of a waveform when alternating current is applied to the common electrode.

FIG. 8 is an example of an experimental result of a voltage holding ratio in the liquid crystal display device of the present invention.

FIG. 9 is a diagram showing a change in drive voltage width depending on a rubbing direction.

FIG. 10 is a diagram showing a change in voltage-transmittance characteristic due to a change in an axial direction of a polarizing plate.

FIG. 11 is a diagram showing voltage-transmittance characteristics.

FIG. 12 is a diagram showing voltage-transmittance characteristics.

[Explanation of symbols]

1 ... Common electrode (common electrode), 2 ... Insulating film, 3 ... Signal electrode (drain electrode), 4 ... Pixel electrode (source electrode), 5
... Alignment film, 6 ... Liquid crystal molecules, 7 ... Substrate, 8 ... Polarizing plate, 9 ...
Electric field, 10 ... rubbing direction, 11 ... polarizing plate transmission axis direction,
12 ... Scan electrode (gate electrode), 13 ... Amorphous silicon, 14 ... Thin film transistor element, 16 ... Capacitance element, 17 ... Control circuit, 18 ... Scan electrode driving circuit, 19 ... Signal electrode driving circuit, 20 ... Common electrode driving Circuit, 21 ... Active matrix type liquid crystal display element, 2
2 ... Black matrix, 23 ... Color filter, 2
4 ... Protecting film / planarizing film, 25 ... Insulating film.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G02F 1/133 550 1/1333 1/1337 500

Claims (8)

[Claims] 1. A display pixel comprises a scanning signal electrode, a video signal electrode,
Composed of a pixel electrode and an active element on the substrate,
An alignment film of liquid crystal is formed on the substrate directly or via an insulating layer, the substrate is arranged to face the other transparent substrate on which the alignment film of liquid crystal is formed, and the liquid crystal layer is sandwiched by both the substrates. Each of the electrodes is configured to apply an electric field substantially parallel to the substrate to the liquid crystal layer, and each of the electrodes is connected to an external control unit capable of arbitrarily controlling the applied electric field according to a display pattern. An active matrix type liquid crystal display device having a polarizing means for changing optical characteristics depending on the alignment state of the liquid crystal layer, wherein the electrodes for driving the liquid crystal are sandwiched between two or more dielectric layers above and below. And the specific resistance of the liquid crystal is 1 × 10 ¹⁴ Ω
· Cm or less, 1 × active matrix type liquid crystal display device, characterized in that it is 10 ⁹ Omega · cm or more. 2. The display pixel comprises a scanning signal electrode, a video signal electrode,
Composed of a pixel electrode and an active element on the substrate,
An alignment film of liquid crystal is formed on the substrate directly or via an insulating layer, the substrate is arranged to face the other transparent substrate on which the alignment film of liquid crystal is formed, and the liquid crystal layer is sandwiched by both the substrates. Each of the electrodes is configured to apply an electric field substantially parallel to the substrate to the liquid crystal layer, and each of the electrodes is connected to an external control unit capable of arbitrarily controlling the applied electric field according to a display pattern. An active matrix liquid crystal display device comprising a polarizing means for changing optical characteristics according to the alignment state of the liquid crystal layer, wherein a ratio 1 / d of an interelectrode gap 1 and a cell gap d is 2.0.
Above, the twist elastic constant K ₂ and the dielectric anisotropy Δ
An active matrix type liquid crystal display device characterized by using a liquid crystal having a relationship of satisfying (Equation 1) between ε. K ₂ /Δε<9.0×10 ⁻⁸ [dyn] (Equation 1) 3. A gap between opposing substrates is 6 μm or less,
The gap between electrodes is 10 μm or more and the driving voltage is 5
3. The active matrix type liquid crystal display device according to claim 2, which is V or less. 4. A liquid crystal compound represented by the general formula (I), wherein at least one cyano group, trifluoromethyl group, trifluoromethoxy group or nitro group is introduced as an end group into the liquid crystal. The active matrix type liquid crystal display device according to claim 1 or 2. [Chemical 1] (In the general formula (I), X _{1 to} X ₃ represent a fluoro group, a cyano group, a trifluoromethyl group, a trifluoromethoxy group, a nitro group or a hydrogen atom, and R represents a C 1 to C 10 which may be substituted. Represents an alkyl group or an alkoxy group of, ring A represents a cyclohexane ring, a benzene ring, a dioxane ring, a pyrimidine ring or a [2,2,2] -bicyclooctane ring, and Z is a single bond, an ester bond, an ether bond or a methylene group. , Methyleneoxy, ethylene, and n is an integer of 1 or 2.) 5. A liquid crystal compound represented by the general formula (II), wherein at least one cyano group, trifluoromethyl group, trifluoromethoxy group or nitro group is introduced into the liquid crystal in the direction of the minor axis of the molecule. The active matrix type liquid crystal display device according to claim 1 or 2, wherein [Chemical 2] (In the general formula (II), X ₁ and X ₂ represent a fluoro group, a cyano group, a trifluoromethyl group, a trifluoromethoxy group, a nitro group or a hydrogen atom, and R represents a C 1 to C 10 which may be substituted. Represents an alkyl group or an alkoxy group of, ring A represents a cyclohexane ring, a benzene ring, a dioxane ring, a pyrimidine ring or a [2,2,2] -bicyclooctane ring, and Z is a single bond, an ester bond, an ether bond or a methylene group. , Methyleneoxy, ethylene, and n is an integer of 1 or 2.) 6. The liquid crystal has a positive dielectric anisotropy and a rubbing angle of 1 ° to 20 ° with respect to the normal direction of the electric field, or the liquid crystal has a negative dielectric anisotropy. 3. The active matrix liquid crystal display device according to claim 1, wherein the rubbing angle is set to 1 to 20 degrees with respect to the electric field direction. 7. The active matrix liquid crystal display device according to claim 1, wherein the common electrode is formed as a part of a display pixel, and an alternating current is applied to the common electrode. 8. The transmission axis of the polarizing plate is 1 ° in the direction in which the molecular axis of the liquid crystal is rotated by applying an electric field with respect to the initial alignment direction of the liquid crystal.
The active matrix type liquid crystal display device according to claim 1, wherein the active matrix liquid crystal display device is shifted as described above.