JPH09160041A - Liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a display element having high speed response and a wide visibility angle. SOLUTION: This display element is formed by a liquid crystal cell 10 forming plural pixels by holding a liquid crystal layer 14 between two opposite substrates 10a, 10b and two polarizers 20a, 20b holding the cell 10 between them and constituted so as to control a double refraction rate by the impression of electric fields. The two substrates 10a, 10b are respectively provided with photoconductor parts (electrodes) 12a, 12b and alignment layers 13 on the sides of the layer 14. The electrodes 12a, 12b are oppositely arranged so as to impress electric fields to the layer 14, the electrode 12a or 12b of at least one of the substrates 10a, 10b has structure alternately arraying the electrodes 12a or 12b with thin width and non-conductive parts 11a or 11b in each pixel, and when both the substrates 10a, 10b are joined, the electrode of one substrate is opposed to the non-conductor part of the other substrate to form oblique electric fields in the layer 14. In each pixel, the alignment layers of the two substrates 10a, 10b orientate liquid crystal molecules in the layer 14 in a tilted state and the liquid crystal molecules are uniformed in the initial alignment state.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a liquid crystal display device.

[0002]

2. Description of the Related Art In recent years, liquid crystal display elements having the great advantages of thinness, light weight, and low power consumption have been used as display devices for personal OA equipment such as Japanese word processors and disk top personal computers. It is actively used. Most of the liquid crystal display elements (hereinafter abbreviated as LCD) use nematic liquid crystal, and the display system can be roughly classified into two systems, a birefringence mode and an optical rotation mode. An LCD of a birefringence mode display method using a twisted nematic liquid crystal is, for example, an LCD (called an ST method) having a molecular arrangement twisted by 180 ° or more, and has steep electro-optical characteristics. Even if there is no switching element (thin film transistor or diode), a large capacity display can be easily obtained by time-division driving.

However, the above-mentioned ST method is not suitable for application products which require high display performance because the response throat is as slow as several hundred milliseconds and the viewing angle characteristics are narrow.

On the other hand, since the LCD of the optical rotation mode has a molecular arrangement twisted by 90 ° (called the TN system) and exhibits a high contrast ratio, a clock, a calculator and a switching element are provided for each pixel. Thus, it is possible to realize an LCD (for example, TFT-LCD) having a large display capacity and high contrast and high display performance.

In recent years, this TN type TFT-LCD performs gradation display, but when observed obliquely, such phenomena as display reversal, blackout, and blank areas occur. Therefore, the viewing angle characteristic is extremely narrow. In addition, the T of this TN method
FT-LCDs have come to be used for large-sized and extremely high-definition application products such as desktop monitors as the quality has been improved. When applied to such fields and high-definition TV applications, extremely fast response speed is required.
In the method, when gradation display is performed, the response time required for pattern rewriting is as slow as 100 milliseconds at maximum.

Further, in order to obtain high contrast characteristics, this TN method requires an operating voltage of 4 to 5 V and consumes high power.

As a means for improving the viewing angle characteristics of the above-mentioned TN method, the viewing angle dependence is improved by using a liquid crystal display element in which two regions in which one liquid crystal molecule rising direction (pretilt direction) is different by 180 ° are provided in one pixel. Method (Two Domain
TN: Abbreviated as TDTN For example, JP-A-64-8852
0) and Domain Divided TN (DDTN abbreviated as Y.Koike, e) that achieves the same effect as TDTN by using a spray arrangement.
t.al., 1992, SID, p798) and the like have been proposed. The purpose of these is to effectively eliminate the above-mentioned extreme value by defining two regions having different viewing angle dependences of the applied voltage-transmittance characteristic as one pixel.

However, in these methods, the resist is patterned in order to change the pretilt direction in a fine region.
The number of processes is increased compared to the conventional TN process, such as patterning and rubbing, patterning and mask exposure to form two kinds of alignment films (surface condition and material) in a fine area. It is not practical because the cost will be significantly high.

Further, although the above-described extreme value can be eliminated in a certain viewing angle range, the viewing angle characteristic is an average characteristic of the individual characteristics of the two regions having different viewing angle dependences, and it should be eliminated depending on the viewing angle direction. I can't. As for the contrast, since the bad characteristic and the good characteristic are averaged, the average characteristic is obtained, and the contrast is lower than that of the good characteristic alone. The response speed is the same as that of the conventional TN method.

On the other hand, Y. Yamaguchi et al. Apply a voltage to a nematic liquid crystal layer having a non-twisted splay alignment and, as a vent alignment, the liquid crystal molecules within the applied voltage range for maintaining this vent alignment. Birefringence effect type liquid crystal display mode: OCB in which the tilt state is controlled by the applied voltage value and the phase difference in the liquid crystal layer is controlled by the voltage
Mode (Optically Compensated Birefringence mode)
(Y. Yamaguchi, et al. SID93 DI
GEST, pp 277-280). Also, the boss (P.Bos
) Et al. Have proposed a similar liquid crystal display mode (P. Bos, e.
tal. SID'83 DIGEST, pp30-3
1).

The liquid crystal molecule arrangement in this OCB mode is characterized in that the upper half and the lower half of the liquid crystal layer are always symmetrical. Therefore, even if the viewing angle (observation angle) is tilted in the left and right directions, the viewing angle characteristics are symmetrical. Further, by disposing the biaxial retardation plate, the refractive index ellipsoid of the liquid crystal layer and the biaxial retardation plate becomes a sphere in a certain voltage state, that is, the three-dimensional refractive index anisotropy. It becomes an optical medium that does not have the above, and by generating a phase difference in the X direction from this state, it becomes possible to perform voltage control in which the phase difference changes from 0 to a half wavelength at various viewing angles, and the above-mentioned viewing angle dependence is almost eliminated. There is no display mode.

As described above, the OCB mode is excellent in terms of the viewing angle characteristics of the gradation performance and the contrast performance described above. However, in the OCB mode, it is necessary to transfer the liquid crystal molecule array from the splay array (no voltage applied state) to the bent array by applying a voltage, which requires strong energy, and in fact It was necessary to apply a voltage higher than the driving voltage (after). Although a TFT is required for high-capacity and high-definition display, the voltage cannot be applied by this TFT element, and the OCB mode cannot be used for high-capacity and high-definition display. In addition, the time required for the transfer takes one minute or more, and it takes time from when the display is started to when the display is displayed, like a CRT display using a vacuum tube.

Further, the OCB mode needs to maintain the vent arrangement (prevents the transition to the spray arrangement), and for this purpose, it is necessary to constantly apply a certain voltage to all the modulation sections. is there. In order to lower the driving voltage of the device as much as possible, it is necessary to set the voltage for maintaining the vent arrangement as the lower limit of the driving voltage range. In this case, the bent arrangement needs to be stably maintained at this applied voltage.
However, the applied voltage with which the vent arrangement is stably maintained is as high as about 2.5 V, and as a result, the drive voltage is high.

Further, in order to obtain a sufficient contrast, an operating voltage of 5 to 8 V is required, and the power consumption is extremely high.

Further, there is also a problem of temperature characteristics that the retardation of the liquid crystal phase changes at high temperature and the display characteristics deteriorate. Further, in production, it is necessary to control the pretilt angles of the upper and lower substrates completely symmetrically, and the margin of unevenness of the pretilt angle in the plane is narrow. Therefore, there is also a problem that the yield is low.

On the other hand, Oe et al. Formed an In-Pla on one side of which an electrode capable of applying an electric field in the substrate plane direction was formed to change the alignment direction of liquid crystal molecules in the substrate plane direction.
The IPS mode (M, Oh-e, et.a.) was proposed in which the ne mode is improved and a TFT array having a simple electrode structure and a TFT-LCD having a molecular arrangement change of 45 ° like SSFLC are proposed.
l. "Principles and Characteristics of Electro-Optic
al Behavior In-Plane Switching Mode ", ASIA DISPLAY
'95 DIGEST PAPER p577-580, 1995).

This IPS mode, like SSFLC, changes the alignment direction of liquid crystal molecules in the plane direction of the substrate, and the retarder
Since the optical axis causing the distortion is controlled by the electric field, the viewing angle characteristics of the gradation display performance and the contrast performance described above are extremely wide. However, the response speed is slow because it is strongly influenced by the alignment regulating force (anchoring) of the liquid crystal molecules. Moreover, the operating voltage is as high as 7 V and the power consumption is extremely high. Further, in principle, liquid crystal molecules on the electrodes cannot be changed, so that the light cannot be deviated on the electrodes, and the electrodes must be made of a light-shielding metal. Therefore, TFT-LCD
As a result, the aperture ratio becomes low and the display brightness becomes extremely dark.

[0018]

As described above, the conventional display mode has problems such as viewing angle characteristics, response speed, driving voltage (power consumption), display brightness, temperature characteristics, etc., all of which are satisfied. There was no LCD to do.

The present invention solves the problems of the conventional display mode, and provides a novel display mode with an extremely high quality.
The purpose is to propose a configuration of code.

[0020]

According to the present invention, firstly, a liquid crystal cell in which a liquid crystal layer is sandwiched between two opposing substrates to form a plurality of pixels, and this liquid crystal cell is sandwiched between two polarizers. In the liquid crystal display element, the two substrates each have an electrode and an alignment film on the liquid crystal layer side, and the electrodes are arranged facing each other so that an electric field can be applied to the liquid crystal layer for each pixel, The electrode of at least one of the substrates has a structure in which narrow conductor portions and non-conductor portions are alternately arranged for each pixel, and the conductor portion of one substrate and the non-conductor portion of the other substrate are at least Part of them are opposed to each other, and in each pixel, the alignment films of the two substrates tilt the liquid crystal molecules of the liquid crystal layer, and the liquid crystal molecules are in a uniform state in an initial alignment state. A liquid crystal display device is obtained.

Here, the non-conductor portion means a gap portion between the conductor portions or a region in which a non-conductor material is formed in this gap.

The basic structure of one pixel of the electrode is shown in FIG. The configuration of a liquid crystal cell in which this electrode is combined is shown in FIG. As shown in FIG. 1A, the electrode 12A on the upper substrate on the observation side has a structure in which stripe-shaped conductor portions 12a having a fine narrow width and non-conductor portions 11a constituting the gap are alternately arranged. Similarly, the pixel electrode 12B on the lower substrate, which is the active matrix substrate on the opposite side, has a structure in which the stripe-shaped conductor portions 12b having a fine width and the non-conductor portions 11b forming the gap are alternately arranged. . Reference numeral 15 represents a TFT switching element.

In the arrangement in which the polarizer 20a as the analyzer, the retardation plate 19, the liquid crystal cell 10 and the polarizer 20b as the polarizer are sequentially stacked as shown in FIG. 2A, Voff is a voltage applied to the electrode of the liquid crystal cell. Shows an optical axis and an absorption axis (illustrated by an arrow) in a state where the liquid crystal is in an initial alignment state, and Von represents an optical axis and an absorption axis (indicated by an arrow when a voltage is applied to the electrodes of the liquid crystal cell). (Shown in the figure).

In this case, light does not pass between the polarizers at Voff, but passes at Von.

FIG. 2B shows liquid crystal molecules 14a when a voltage is applied.
Shows that the liquid crystal arranged in parallel with the conductor portion 12 of the electrode is twisted and aligned when viewed from the observation side when a voltage is applied to the electrode. A view of this from the cross-sectional direction of the liquid crystal layer is (c).

When a voltage is applied to the liquid crystal display element of the present invention like this liquid crystal cell, an oblique electric field is applied to the liquid crystal layer as shown in FIG. 2C, and the liquid crystal molecules 14a follow the oblique electric field. To arrange.

The liquid crystal display device having the structure of the present invention is shown in FIG.
A periodic oblique electric field as shown in (c) can be applied to the liquid crystal layer, and the liquid crystal layer as a whole can be easily applied in the thickness direction, the in-plane direction, and the liquid crystal molecules on the electrodes. An electric field is applied to. Reference numeral 21 indicates a power source for applying a voltage to the electrodes.

Since the liquid crystal cell 10 is sandwiched between the two polarizing plates 20a and 20b, the polarization is controlled and the transmission / absorption of the incident light is controlled as in the conventional display mode described above. Type liquid crystal display device.

The liquid crystal cell used in the present invention is a liquid crystal cell capable of applying an oblique electric field, like the liquid crystal display element disclosed in Japanese Patent Application No. 06-121634 by the present inventors. However, the liquid crystal display element disclosed in Japanese Patent Application No. 06-121634 does not have an analyzer, although it has a means for allowing polarized light to enter the cell. That is, the configuration does not use two polarizing plates. On the other hand, in the present invention, the liquid crystal cell is sandwiched between two polarizing plates. this is,
The liquid crystal display element disclosed in Japanese Patent Application No. Hei 06-121634 is not a direct-view type but a projection type for controlling transmission / scattering of incident light in the liquid crystal display element, and is different in structure and function. It is a thing. Further, the present invention controls transmission / absorption of incident light as described above, and various conditions particularly suitable for the purpose of the present invention are different from those in the above-mentioned Japanese Patent Application No. 06-121634, as will be described later. ing.

In the constitution of the present invention, the alignment film has the effect of tilt-aligning the liquid crystal molecules, and the liquid crystal molecules are in the uniform state in the initial alignment state. This is the cell substrate 1
If one direction with respect to the 0b plane is the X direction, the substrate direction perpendicular to it is the Y direction, and the substrate normal direction is the Z direction, the angle between the optical axis of the liquid crystal molecule 14a and the X and Y planes is between cells. The feature is that + and-do not change. This conceptual diagram is shown in FIG. Figure 7 shows a conceptual diagram of uniform layout.
(A). The liquid crystal molecules 14a tilt obliquely in parallel. In this configuration, the rotation of the optical axis in the X and Y directions is not specified.

FIG. 7 shows the liquid crystal alignment between the upper and lower substrates 10a and 10b.

A second aspect of the present invention is a liquid crystal cell in which a liquid crystal layer is sandwiched between two opposing substrates to form a plurality of pixels, and a liquid crystal display element in which the liquid crystal cell is sandwiched by two polarizers. In the above, the two substrates each have an electrode and an alignment film on the liquid crystal layer side, and the electrodes are arranged so as to face each other so that an electric field can be applied to the liquid crystal layer for each pixel.
The electrode of at least one of the substrates has a structure in which narrow conductor portions and non-conductor portions are alternately arranged for each pixel, and the conductor portion of one substrate and the non-conductor portion of the other substrate are at least Some of them are opposed to each other, and in each pixel, the alignment films of the two substrates tilt the liquid crystal molecules of the liquid crystal layer, and the liquid crystal molecules are in a splay state in an initial alignment state. To obtain a liquid crystal display device.

In the constitution of the present invention, the alignment film has the effect of tilt-aligning the liquid crystal molecules, and the liquid crystal molecules are in the splay state in the initial alignment state. In the conceptual diagram of FIG. 6, assuming that one direction is the X direction with respect to the substrate surface of the cell, the Y direction is the substrate direction perpendicular to the X direction, and the Z direction is the substrate normal direction, X is the optical axis of the liquid crystal molecule. It is characterized in that the angle formed with the Y plane coincides with the X and Y planes at a certain Z value between cells, and + and − change before and after that. A conceptual diagram of this spray arrangement is shown in FIG. Liquid crystal molecule 14a
Have opposite tilt directions with the center of the layer sandwiched. In this configuration, the rotation of the optical axis in the X and Y directions is not specified.

Thirdly, in a liquid crystal display element in which a liquid crystal layer is sandwiched between two opposing substrates to form a plurality of pixels and a liquid crystal cell is sandwiched by two polarizers, The two substrates each have an electrode and an alignment film on the liquid crystal layer side, the electrodes are arranged so as to be able to apply an electric field to the liquid crystal layer for each pixel, and at least one of the substrates has an electrode. Each has a structure in which a narrow conductor portion and a non-conductor portion are arranged alternately, the conductor portion of one substrate and the non-conductor portion of the other substrate are opposed at least in part, In each pixel, the alignment films of the two substrates align the liquid crystal molecules of the liquid crystal layer horizontally with respect to the substrate surface, and the liquid crystal molecules are in an initial alignment state and horizontal with respect to the substrates. To obtain a liquid crystal display device characterized by That.

In the structure of the present invention, liquid crystal molecules are aligned horizontally in the substrate direction in the initial alignment state. In the conceptual diagram of FIG. 6, the angle formed by the optical axes of the liquid crystal molecules with the X and Y planes is 0 ° at any position in the initial state. A conceptual diagram of this horizontal array is shown in FIG.
The liquid crystal molecule orientation is opposite to the substrate surface. In this configuration,
The rotation of the optical axis in the X and Y directions is not specified.

Further, fourthly, in a liquid crystal display element comprising a liquid crystal cell sandwiching a liquid crystal layer between two opposing substrates to form a plurality of pixels and a liquid crystal cell sandwiched by two polarizers. The two substrates each have an electrode and an alignment film on the liquid crystal layer side, the electrodes are arranged so as to be able to apply an electric field to the liquid crystal layer for each pixel, and at least one of the substrates has an electrode. Each has a structure in which a narrow conductor portion and a non-conductor portion are arranged alternately, the conductor portion of one substrate and the non-conductor portion of the other substrate are opposed at least in part, In each pixel, the alignment films on the two substrates tilt-align the liquid crystal molecules of the liquid crystal layer, and the liquid crystal molecules operate in a bend alignment state to obtain a liquid crystal display element.

The structure of the present invention is as follows:
At a certain voltage or more, the liquid crystal molecules are arranged in the Z direction in the center between the substrates, and one is in the + direction with respect to the X and Y planes and the other is in the − direction as it approaches the substrate surface.
A conceptual diagram of this bend arrangement is shown in FIG. The liquid crystal molecules 14a become vertical at the center of the layer. In this configuration, the rotation of the optical axis in the X and Y directions is not specified.

Fifthly, in a liquid crystal display element comprising a liquid crystal cell sandwiching a liquid crystal layer between two opposing substrates to form a plurality of pixels and a liquid crystal cell sandwiched by two polarizers, The two substrates each have an electrode and an alignment film on the liquid crystal layer side, the electrodes are arranged so as to be able to apply an electric field to the liquid crystal layer for each pixel, and at least one of the substrates has an electrode. Each has a structure in which a narrow conductor portion and a non-conductor portion are arranged alternately, the conductor portion of one substrate and the non-conductor portion of the other substrate are opposed at least in part, In each pixel, the liquid crystal display element is characterized in that the pixel on one substrate is tilt-aligned and the pixel on the other substrate is vertically aligned so that liquid crystal molecules are in a hybrid alignment state in an initial state. I will get it.

The structure of the present invention is as follows in the conceptual diagram of FIG.
The optical axis of the liquid crystal molecules is in the Z direction at the interface of one substrate, continuously changes from that direction, and the optical axis approaches the X and Y plane directions toward the other substrate. A conceptual diagram of this hybrid sequence is shown in FIG. The liquid crystal molecules 14a are tilted on the lower substrate 10b side, and the upper substrate 10b is tilted.
Become vertical on the side. In this configuration, the rotation of the optical axis in the X and Y directions is not specified.

Further, sixthly, in each pixel, a liquid crystal display element is obtained in which pixels on two substrates are subjected to vertical alignment treatment, and liquid crystal molecules are vertically aligned in an initial state. .

The structure of the present invention is as follows in the conceptual diagram of FIG.
The optical axis of the liquid crystal molecules is in the Z direction at the interface of one substrate, and the optical axis approaches the other substrate continuously from there in the X axis direction. In this configuration, the Y direction of the optical axis is not specified.

Furthermore, the present invention provides a liquid crystal display device characterized in that, in the above, the width of the conductor portion and the non-conductor portion of the electrode is 50 μm or less for each pixel.

Furthermore, the present invention is characterized in that in each pixel, liquid crystal molecules are twisted and aligned between the substrates in the initial state.

In the structure of the present invention, the optical axes of the liquid crystal molecules are always arranged in the Z direction between the cells. A conceptual diagram of this vertical arrangement state is shown in FIG. The liquid crystal molecules 14a are arranged in the substrate normal line Z direction.

Furthermore, the present invention is characterized in that, in each pixel, liquid crystal molecules are twisted and aligned by 0 to 360 ° between the substrates in the initial state.

The structure of the present invention is such that the optical axis of liquid crystal molecules is twisted by 0 to 360 ° in the X and Y directions with respect to the change in the Z direction between cells. In this configuration, the Z direction of the optical axis is not specified.

Furthermore, the present invention is characterized in that in each pixel, liquid crystal molecules are twisted and aligned by 0 to 180 degrees between the substrates in the initial state.

The structure of the present invention is such that the optical axis of liquid crystal molecules is twisted by 0 to 180 degrees in the X and Y directions with respect to changes in the Z direction between cells. In this configuration, the Z direction of the optical axis is not specified.

If the twist angle is 0 to 180 °,
Since the liquid crystal molecules rotate only in a specific direction, the liquid crystal molecules can be switched without undue strain.

Furthermore, the present invention is characterized in that the alignment directions of the upper and lower substrates form an angle of 45 ° with the electrode direction of both the upper and lower substrates.

Since the birefringence effect is maximized when the angle with the polarizing plate is 45 °, high transmittance can be obtained by switching the angle with the polarizing plate in the range of 45 ° to 0 °.

Further, the present invention is characterized in that, in each pixel, liquid crystal molecules are twisted and aligned by 90 ° between the substrates in the initial state.

A liquid crystal display device having a wide margin can be obtained by twisting the liquid crystal in a state of being twisted by 90 ° and rotating the liquid crystal to untwist it by applying a voltage.

Further, the present invention is characterized in that a nematic liquid crystal, a cholesteric liquid crystal, a nematic liquid crystal (including a case where a chiral agent is added to a nematic liquid crystal to have a chiral pitch), a smectic liquid crystal or a discotic liquid crystal is used as the liquid crystal composition. And

Furthermore, the present invention is characterized in that a liquid crystal composition having a negative dielectric anisotropy is used as the liquid crystal composition.

Further, in the present invention, the two polarizers are
The absorption axes are arranged so as to be orthogonal to each other, and in a state where no voltage is applied to the liquid crystal display element, the alignment orientation of the liquid crystal molecules in the liquid crystal display element plane is one absorption axis of the two polarizing plates. It is arranged in parallel with.

[0057]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

(Embodiment 1) FIG. 1 shows an example of an electrode structure of a liquid crystal display device according to an embodiment of the present invention. (A) is a plan view of one pixel region of a counter electrode on an upper substrate, and (b) is a plan view of pixel electrodes on a lower substrate.

FIG. 3 shows the structure of the present liquid crystal display device. An ITO patterning glass substrate for a common substrate in which a black matrix 16 made of chromium is formed on the entire non-pixel portion is used as the upper substrate 10a, and a glass substrate with a switching element 15 made of TFT is used as the lower substrate 10b. ITO is used for the pixel electrode 12B of the lower substrate 10b similarly to the electrode 12A of the upper substrate. As shown in FIG. 1, the electrodes on the upper and lower substrates are patterned in stripes to form conductor portions 12a and 12b and non-conductor portions 11a and 11b, and at least one of the conductor portions 12a and 12b of one electrode is formed. The portion is arranged so as to face the non-conductor portions 11b and 11a of the other electrode.

Using such a substrate, AL-3046 (pretilt angle measured value 3 °) made by Japan Synthetic Rubber Co., Ltd. was formed as the alignment film 13, and the alignment electrode 13 was formed in the direction of the stripe electrodes.
Rubbing treatment was performed in the direction of 45 °. At this time, the rubbing directions of the upper and lower substrates were antiparallel. Then, as a substrate interstitial agent on the lower substrate side, the liquid crystal layer thickness was 2.5 μm, and microparticles (particle size 2.5 μm) manufactured by Sekisui Fine Chemical Co., Ltd. were dispersed at a density of 100 particles / mm ^2. Liquid crystal material ZLI-11 manufactured by Merck Japan Co., Ltd., which has a positive dielectric anisotropy between the substrates, is sprayed by a dry spraying method.
Sandwiching the liquid crystal 14 consisting of 32 (Δn = 0.14),
A liquid crystal cell 10 was obtained.

Further, in order to compensate the optical rotatory dispersion, FIG.
, A retardation plate 19 is arranged on the cell, and polarizing plates 20a and 20b are arranged on the liquid crystal cell so that the absorption axes are aligned with the rubbing direction and the direction orthogonal to the rubbing direction. The device was obtained.

Incidentally, FIG. 2A is a diagram showing an optical configuration of the liquid crystal display element of the present embodiment, and FIG.
Is a plan view thereof, and FIG. 2C is a sectional view thereof. Figure 2 (c)
The alignment state of the liquid crystal molecules inside the cell of the liquid crystal display element of this embodiment is shown in FIG.

FIG. 4 shows a model of the molecular arrangement viewed from the substrate normal direction. (A) shows the initial state, and (b) shows the molecular alignment state after voltage application. The rubbing direction is 45 with respect to the electrode.
The liquid crystal has a homogeneous alignment in the direction of °.

As shown in FIG. 4, since the light is oriented uniformly in the initial state, the transmitted light becomes almost zero. When a voltage is applied to this cell, the liquid crystal is gradually twisted and arranged at an angle θ in the direction of the electric field, and when a sufficient voltage is applied, the liquid crystal becomes an arrangement state as shown in FIG. 4B. . (B)
As shown in FIG. 7, when a voltage is applied to the liquid crystal molecules 14a, the oblique electric field causes the liquid crystal molecules 14a to move from 45 ° from the electrode direction to 90 ° in the non-conductor portion.
Since the polarizing plate is oriented at 45 ° to the electrodes,
By applying a voltage, a birefringence effect starts to occur and the transmitted light intensity increases.

As shown in FIG. 2C, when a voltage is applied to this element, an oblique electric field is applied to the liquid crystal layer from one conductor portion to the electrode of the other substrate. Therefore, when viewed from the stripe electrode direction, the liquid crystal molecules are in a molecular alignment state in which they are slightly inclined between the electrodes. Since this inclination is opposite for each electrode, the retardation of the liquid crystal layer in the pixel is compensated, and thereby the viewing angle characteristic is also compensated. Therefore, in the present liquid crystal display element, good viewing angle characteristics can be obtained.

A voltage is applied to the liquid crystal display element thus obtained through a TFT, and electro-optical characteristics (transmittance-
The applied voltage curve) was measured. FIG. 5 shows the TV characteristic.

The curve a is the case where the retardation plate is not inserted in the liquid crystal display element, and the curve b is the case where the retardation plate is inserted. As can be seen from this result, this liquid crystal display device can be driven at a low voltage, and if it is compensated by a retardation plate, a high transmittance can be obtained.

Further, when the viewing angle of the liquid crystal display device of the present invention was measured, a contrast of 10: 1 or more was obtained in the region of 60 ° both vertically and horizontally.

When the response time was measured, a high-speed response with a rising time of 6 ms and a falling time of 9 ms could be obtained.

As described above, the liquid crystal display device of the present invention makes it possible to obtain a liquid crystal display device having high-speed response, high contrast, and wide viewing angle.

(Embodiment 2) In the structure of FIG. 3, a liquid crystal display device of this embodiment was obtained by using an active matrix substrate as a lower substrate and a substrate having a color filter formed on an upper substrate. The other conditions are the same as those in the first embodiment.

When an image was displayed on this liquid crystal display device, good characteristics with a wide viewing angle were obtained. In addition, when a moving image was displayed, an easy-to-see image with fast response time was obtained.

(Embodiment 3) In this embodiment, the rubbing direction of one of the substrates in Embodiment 1 is reversed to obtain a splay alignment state of liquid crystal molecules. In the splay alignment, the degree of freedom of rising of the liquid crystal molecules is higher than that in the above-described embodiment in which the tilt alignment is performed, and therefore the liquid crystal molecules move in the direction of the electric field due to the oblique electric field. On the other hand, in the tilt-aligned cell of the above-described embodiment, one oblique electric field can be directed in that direction as it is, but the other electric field needs to rise in the direction opposite to the tilt direction, so that a certain voltage is required. The movement of the liquid crystal molecules varies depending on the direction of the oblique electric field. On the other hand, in the spray cell, since it rises similarly with respect to the oblique electric field in either direction, better characteristics can be obtained.

When the TV characteristic of the liquid crystal display device thus obtained was measured in the same manner as described above, the result as shown by the curve c in FIG. 5 could be obtained. When various characteristics were measured by applying a voltage through the TFT switching element of the matrix substrate, good characteristics were obtained in terms of transmittance, contrast, viewing angle and response time.

(Embodiment 4) Further, in the liquid crystal display element of the present embodiment, polyvinyl alcohol (PVA) was applied to the substrate as an alignment film to form an alignment film. Since this cell has a high degree of freedom in rising, similar to the spray arrangement,
The oblique electric field causes movement in the electric field direction.

A voltage was applied to the thus obtained liquid crystal display device through the TFT in the same manner as described above, and various characteristics were measured. As a result, excellent transmittance, contrast, viewing angle and response time were obtained. The characteristics were obtained.

(Fifth Embodiment) Further, a voltage is applied to the splay alignment cell of the third embodiment to obtain a bent alignment liquid crystal display device. At this time, the alignment film is SE-1 manufactured by Nissan Chemical Co., Ltd.
As a liquid crystal composition, a polyimide of 50 is used.
926 (manufactured by E. Merck), micropearls having a size of 6 μm were used, and the other conditions were the same as those in the above-mentioned examples.

A voltage was applied to the liquid crystal display device thus obtained through a TFT in the same manner as above, and various characteristics were measured. As a result, excellent characteristics were obtained in terms of transmittance, contrast and viewing angle. Was given. Further, since the response time is a bend arrangement, a particularly fast value of 2.5 ms for rising and 4.5 μm for falling was obtained.

(Embodiment 6) In the structure of FIG. 3, a color filter substrate is used as an upper substrate as an alignment film,
Forming an alignment agent for vertical alignment (ODS-E: manufactured by Chisso),
The alignment film SE-150 was applied to the TFT substrate side and rubbed in the direction of 45 ° with respect to the electrode direction to form the alignment film. Then, 3.5 μm of micropearl was dispersed, and the other conditions were the same as in the above-mentioned example to form a liquid crystal display element.

A voltage was applied to the thus obtained liquid crystal display device through the TFT in the same manner as above, and various characteristics were measured. As a result, excellent characteristics were obtained in terms of transmittance, contrast and viewing angle. Was given. Further, since the response time is a hybrid arrangement, a particularly fast value of 4 ms for rising and 5 ms for falling was obtained.

(Embodiment 7) In the configuration of FIG. 3, as an alignment film, an active matrix substrate is used as a lower substrate, a color filter substrate is used as an upper substrate, and an alignment agent for vertical alignment (ODS-E: manufactured by Chisso) is used for both. A liquid crystal display element was formed in the same manner as in Embodiment 1 except for the above.

The liquid crystal display elements arranged vertically also have a molecular arrangement as shown in FIG. 4B when a voltage is applied, and a sufficient birefringence effect is produced. Further, since the tilt directions of the liquid crystal molecules are opposite to the left and right of the conductor, the viewing angle is compensated.

A voltage was applied to the thus obtained liquid crystal display device through the TFT in the same manner as described above, and various characteristics were measured. As a result, it was found that the transmittance, contrast, viewing angle and response time were good. The characteristics were obtained.

(Embodiment 8) In Embodiment 2, the rubbing direction of the alignment film of the color filter substrate, which is the upper substrate, is set at 90 ° with respect to the rubbing direction of the upper substrate having the pixel electrodes, and implantation is performed. A chiral agent was added to the liquid crystal material in an amount of 0.2 wt%, and then a liquid crystal cell was prepared in the same manner as in Embodiment 2, and two polarizing plates were arranged in the same direction as the electrode direction to prepare a liquid crystal display element.

In the initial state of this cell, 90 ° liquid crystal molecules are twisted, and one polarization component twists the liquid crystal layer to produce black. When a voltage is applied, the twisted liquid crystal molecules are oriented in the direction of the electric field, so that the liquid crystal molecules are oriented at about 45 ° with respect to the electrodes, and light is transmitted by the birefringence effect.

A voltage was applied to the thus obtained liquid crystal display device through the TFT in the same manner as described above, and various characteristics were measured. As a result, it was found that the transmittance, contrast, viewing angle and response time were good. The characteristics were obtained.

(Embodiment 9) In Embodiment 2, 5 wt% of a chiral agent is added to the liquid crystal material to be injected,
In addition, a liquid crystal display device was produced in the same manner as in Embodiment 2 except that 2.0 μm silica was used as the spacer.

In the initial state of this cell, 360 ° liquid crystal molecules are twisted, and since the liquid crystal molecules are completely out of the optical rotation condition, the light polarized by the polarizing plate is reflected by the other polarizing plate. Completely shut off,
The display becomes black.

Then, when an oblique electric field is applied, the liquid crystal molecules are unwound and aligned in the direction orthogonal to the electrodes.
Therefore, light is transmitted through the birefringence effect of liquid crystal molecules, and display is possible.

A voltage was applied to the liquid crystal display device thus obtained through the TFT in the same manner as described above, and various characteristics were measured. As a result, it was found that the transmittance, contrast, viewing angle and response time were good. The characteristics were obtained.

(Embodiment 10) In Embodiment 2, the liquid crystal material is made to have a rubbing direction of the alignment film on the color filter substrate side at 90 ° from the rubbing treatment direction on the matrix substrate side, and the liquid crystal material to be injected has a chiral agent. 3w
A liquid crystal display device was manufactured in the same manner as in Embodiment 2 except that a phase difference plate was added between the liquid crystal cell and the polarizing plate after adding t%. At this time, the liquid crystal molecules 270 in the liquid crystal cell.
Twisted. Then, a retardation plate is arranged to set the normally black mode.

By applying a voltage, the liquid crystal molecules are aligned in the direction orthogonal to the electrodes, so that the retardation of the liquid crystal layer is changed and light is transmitted.

A voltage was applied to the thus obtained liquid crystal display device through the TFT in the same manner as described above, and various characteristics were measured. As a result, it was found that the transmittance, contrast, viewing angle and response time were excellent. The characteristics were obtained.

(Embodiment 11) CS-2005 manufactured by Chisso Petrochemical Co., Ltd. is used as a liquid crystal layer, and the rubbing direction is orthogonal to the electrodes.
A liquid crystal cell was formed in the same manner as in Embodiment 2 except that 8 μm of silica was used. The polarizing plate is in the rubbing direction.

By applying a voltage, the liquid crystal molecules are converted into C
Since switching is performed by the tilt angle of S-2005, display can be performed by the birefringence effect.

A voltage was applied to the thus obtained liquid crystal display device through the TFT in the same manner as described above, and various characteristics were measured. As a result, excellent transmittance, contrast, viewing angle and response time were obtained. The characteristics were obtained.

(Embodiment 12) A liquid crystal layer manufactured by Chisso
A liquid crystal cell was formed in the same manner as in Embodiment 2 except that the type liquid crystal (EN-35) was used.

A voltage was applied to the thus obtained liquid crystal display device through the TFT in the same manner as described above, and various characteristics were measured. As a result, excellent transmittance, contrast, viewing angle and response time were obtained. The characteristics were obtained.

(Embodiment 13) A liquid crystal display element was manufactured in the same manner as in Embodiment 2 except that discotic liquid crystal was used as the liquid crystal layer.

A voltage was applied to the thus obtained liquid crystal display device through the TFT in the same manner as above, and various characteristics were measured. As a result, excellent characteristics were obtained in terms of transmittance, contrast and viewing angle. Was given.

(Embodiment 14) A liquid crystal display device was manufactured in the same manner as in Embodiment 2 except that a discotic liquid crystal and a nematic liquid crystal ZLI-3926 were synthesized as the liquid crystal layer.

A voltage was applied to the thus obtained liquid crystal display device through the TFT in the same manner as above, and various characteristics were measured. As a result, excellent characteristics were obtained in terms of transmittance, contrast and viewing angle. Was given.

In addition, in the examples, the liquid crystal display element of the present invention was manufactured by using a specific material and a specific manufacturing method. However, similar effects can be obtained as long as the materials and conditions are such that the function of the present invention can be obtained. Needless to say, the same effect can be obtained even if the switching element to be used is another element such as MIM or a display element having a simple matrix electrode structure not using the element. .

Further, the present invention can be applied to a guest-host type liquid crystal display device in which a dichroic dye capable of omitting one or all of the two polarizers is mixed. In that case,
It is possible to use not only one liquid crystal cell but also a plurality of liquid crystal cells.

[0105]

According to the present invention, it is possible to obtain a liquid crystal display element having a wide viewing angle and a high speed response.

[Brief description of the drawings]

1A and 1B show an electrode structure of one embodiment for explaining the present invention, in which FIG. 1A is a plan view of an electrode on an upper substrate, and FIG. 1B is a plan view of an electrode structure on a lower substrate.

FIG. 2 illustrates a liquid crystal display device of the present invention.
(A) is a layout drawing showing the relationship between the optical axis and the absorption axis of each element,
(B) is a plan view for explaining the twisting motion of liquid crystal molecules,
(C) is a cross-sectional view showing how an electric field is applied to the liquid crystal layer,

FIG. 3 is a cross-sectional view illustrating the structure of the liquid crystal display element according to the embodiment of the present invention,

4A and 4B are views for explaining liquid crystal molecule alignment of a liquid crystal display element according to an embodiment of the present invention, FIG. 4A is a plan view showing an initial state, and FIG. 4B is a plan view showing a voltage application state;

FIG. 5 is a curve diagram showing electro-optical characteristics of each embodiment of the present invention,

FIG. 6 is a perspective view defining an azimuth for explaining a liquid crystal display device of the present invention,

7 (a) to 7 (f) are conceptual diagrams for explaining an arrangement state of liquid crystal molecules of the liquid crystal display element of the present invention.

[Explanation of symbols]

 10 ... Liquid crystal cell 10a, 10b ... Substrate 11a, 11b ... Non-conductor part 12a, 12b ... Conductor part 13 ... Alignment film 14 ... Liquid crystal layer 14a ... Liquid crystal molecule 15 ... Switching element 16 ... Black matrix 19 ... Retardation plate 20a , 20b ... Polarizer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hitoshi Hato 8 Shinsita-cho, Isogo-ku, Yokohama-shi, Kanagawa Stock company Toshiba Yokohama office (72) Inventor Makiko Sato 8 Shinsugita-cho, Isogo-ku, Yokohama, Kanagawa Company Toshiba Yokohama Office

Claims (17)

[Claims] 1. A liquid crystal display device comprising a liquid crystal cell sandwiching a liquid crystal layer between two opposing substrates to form a plurality of pixels, and a liquid crystal display device comprising the liquid crystal cell sandwiched between two polarizers. Each have an electrode and an alignment film on the liquid crystal layer side, the electrodes are arranged so as to face each other so that an electric field can be applied to the liquid crystal layer for each pixel, and at least one of the electrodes on the substrate has a narrow width for each pixel. Of a conductive portion and a non-conductive portion of the structure is alternately arranged, the conductive portion of the one substrate and the non-conductive portion of the other substrate are opposed at least in part, in each pixel, A liquid crystal display device, wherein the alignment films of the two substrates tilt the liquid crystal molecules of the liquid crystal layer and the liquid crystal molecules are in a uniform state in an initial alignment state. 2. A liquid crystal display device comprising a liquid crystal cell sandwiching a liquid crystal layer between two opposing substrates to form a plurality of pixels, and a liquid crystal display device comprising the liquid crystal cell sandwiched between two polarizers. Each have an electrode and an alignment film on the liquid crystal layer side, the electrodes are arranged so as to face each other so that an electric field can be applied to the liquid crystal layer for each pixel, and at least one of the electrodes on the substrate has a narrow width for each pixel. Of the conductive material portion and the non-conductive material portion are alternately arranged, the conductive material portion of one substrate and the non-conductive material portion of the other substrate are opposed at least in part, in each pixel, A liquid crystal display element, wherein the alignment films of the two substrates align the liquid crystal molecules of the liquid crystal layer in a tilted state, and the liquid crystal molecules are in a splay state in an initial alignment state. 3. A liquid crystal display device comprising a liquid crystal cell having a liquid crystal layer sandwiched between two opposing substrates to form a plurality of pixels, and a liquid crystal display element having the liquid crystal cell sandwiched by two polarizers. Each have an electrode and an alignment film on the liquid crystal layer side, the electrodes are arranged so as to face each other so that an electric field can be applied to the liquid crystal layer for each pixel, and at least one of the electrodes on the substrate has a narrow width for each pixel. Of a conductive portion and a non-conductive portion of the structure is alternately arranged, the conductive portion of the one substrate and the non-conductive portion of the other substrate are opposed at least in part, in each pixel, The alignment films of the two substrates align the liquid crystal molecules of the liquid crystal layer horizontally with respect to the substrate surface, and the liquid crystal molecules are in an initial alignment state and in a horizontal state with respect to the substrates. Liquid crystal display device. 4. A liquid crystal cell in which a liquid crystal layer is sandwiched between two opposing substrates to form a plurality of pixels, and a liquid crystal display element in which the liquid crystal cell is sandwiched by two polarizers, the two substrates Each have an electrode and an alignment film on the liquid crystal layer side, the electrodes are arranged so as to face each other so that an electric field can be applied to the liquid crystal layer for each pixel, and at least one of the electrodes on the substrate has a narrow width for each pixel. Of a conductive portion and a non-conductive portion of the structure is alternately arranged, the conductive portion of the one substrate and the non-conductive portion of the other substrate are opposed at least in part, in each pixel, A liquid crystal display device, wherein the alignment films of the two substrates tilt-align the liquid crystal molecules of the liquid crystal layer, and the liquid crystal molecules operate in a bend alignment state. 5. A liquid crystal display device comprising a liquid crystal cell sandwiching a liquid crystal layer between two opposing substrates to form a plurality of pixels, and a liquid crystal display element comprising the liquid crystal cell sandwiched between two polarizers. Each have an electrode and an alignment film on the liquid crystal layer side, the electrodes are arranged so as to face each other so that an electric field can be applied to the liquid crystal layer for each pixel, and at least one of the electrodes on the substrate has a narrow width for each pixel. Of a conductive portion and a non-conductive portion of the structure is alternately arranged, the conductive portion of the one substrate and the non-conductive portion of the other substrate are opposed at least in part, in each pixel, A liquid crystal display device, wherein the pixels on one substrate are subjected to tilt alignment, and the pixels on the other substrate are subjected to vertical alignment treatment so that liquid crystal molecules are in a hybrid alignment state in an initial state. 6. The liquid crystal display device according to claim 1, wherein in each pixel, pixels on two substrates are subjected to vertical alignment treatment, and liquid crystal molecules are vertically aligned in an initial state. 7. The liquid crystal display element according to claim 1, wherein the width of the conductor portion and the width of the non-conductor portion of the electrode is 50 μm or less for each pixel. 8. The liquid crystal display element according to claim 1, wherein liquid crystal molecules in each pixel are twisted and aligned between the substrates in an initial state. 9. The liquid crystal display device according to claim 8, wherein in each pixel, liquid crystal molecules are twisted and aligned in a range of 0 to 360 ° between the substrates in an initial state. 10. The liquid crystal display device according to claim 8, wherein in each pixel, liquid crystal molecules are twisted and aligned in a range of 0 to 180 ° between the substrates in an initial state. 11. The liquid crystal display element according to claim 1, wherein the orientation treatment directions of the two substrates form an angle of 45 ° with the electrode direction of both substrates. 12. The liquid crystal display element according to claim 1, wherein, in each pixel, liquid crystal molecules are twisted and aligned by 90 ° between the two substrates in an initial state. 13. The liquid crystal display device according to claim 1, wherein a nematic liquid crystal, a cholesteric liquid crystal, a smectic liquid crystal or a discotic liquid crystal is used for the liquid crystal layer. 14. The liquid crystal display device according to claim 1, wherein the liquid crystal layer is sandwiched between polymers. 15. The liquid crystal display device according to claim 1, wherein the liquid crystal composition is polymerized. 16. The liquid crystal display device according to claim 1, wherein a liquid crystal composition having a negative dielectric anisotropy is used for the liquid crystal layer. 17. The two polarizers are arranged such that their absorption axes are orthogonal to each other, and in a state where no voltage is applied to the liquid crystal cell, the alignment orientation of the liquid crystal molecules of the liquid crystal layer on the substrate plane is 2 or more. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is arranged in parallel with one absorption axis of one of the two polarizers.