KR101868475B1 - fabricating method of liquid crystal display device and liquid crystal display device - Google Patents

Abstract

The present invention relates to a method of manufacturing a liquid crystal display device using a high-contrast polymer ferroelectric liquid crystal and a liquid crystal display device, and more particularly, to a method of manufacturing a liquid crystal display device using a high- A liquid crystal material containing a polymeric ferroelectric liquid crystal is sealed between a first substrate on which the first alignment film is formed and a second substrate on which the second alignment film is formed to form a liquid crystal layer And performing an electric field application process by quenching with a temperature gradient of 10 [deg.] C / min from the ISO temperature (110 [deg.] C) to a room temperature at a frequency of 50 to 75 Hz after the liquid crystal layer forming step, Is characterized by firing the first and second alignment films at a temperature of 250 ° C to 350 ° C for 30 minutes in a nitrogen atmosphere or an air atmosphere.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of manufacturing a liquid crystal display device,

The present invention relates to a method of manufacturing a liquid crystal display element and a liquid crystal display element, and more particularly, to a method of manufacturing a liquid crystal display element using a polymeric ferroelectric liquid crystal as a liquid crystal material and a liquid crystal display element.

Recently, liquid crystal display devices have been put to practical use as lightweight, thin and low power consumption video display devices. A general liquid crystal display device practically used is a liquid crystal display device using a nematic liquid crystal.

A liquid crystal display device using a nematic liquid crystal includes two substrates opposed to each other, a transparent electrode formed on an opposing surface of each substrate, an alignment film formed on the transparent electrode of each substrate and subjected to alignment treatment by a rubbing method, And a liquid crystal layer made of a nematic liquid crystal injected between the substrates.

Numerous LCD modes using nematic liquid crystals such as TN (Twisted Nematic), ECB (Electrically Controlled Birefringence), STN (Super Twisted Nematic), IPS (In-Plane Switching) and VA (Virtical Alignment)

However, liquid crystal display devices using nematic liquid crystals are capable of continuous gradation display, but in principle do not have bistability (memory property).

In addition, a liquid crystal display element using a nematic liquid crystal has high alignment uniformity, and high contrast can be realized.

On the other hand, an alignment film oriented by a rubbing method is used for orienting a nematic liquid crystal.

Further, a liquid crystal display device using a nematic liquid crystal realizes a response speed that can be applied to a home television or the like (motion picture response is possible), and it is not easy to respond to a high-speed response of 1 ms or less from the principle of a nematic liquid crystal.

In order to improve the response speed of a liquid crystal display device, a liquid crystal display device of a surface stabilized-ferroelectric liquid crystal (SS-FLC) mode using a low-molecular ferroelectric liquid crystal instead of a nematic liquid crystal has been proposed. The SS-FLC mode liquid crystal display device using a low-molecular ferroelectric liquid crystal has a structure in which a nematic liquid crystal in a liquid crystal layer is substituted with a low-molecular ferroelectric liquid crystal.

The liquid crystal display device using the low-molecular ferroelectric liquid crystal in the SS-FLC mode can improve the response speed as compared with the liquid crystal display device using the nematic liquid crystal, and in principle can not perform continuous gradation display though it has a pair safety.

It is necessary to apply techniques such as area gradation, domain gradation, and frame gradation to perform continuous gradation display in a liquid crystal display element of the SS-FLC mode using a low-molecular ferroelectric liquid crystal (see, for example, Patent Document 1) There is a problem that the structure is complicated and the cost is increased.

In addition, the liquid crystal display device of the SS-FLC mode using the low molecular weight ferroelectric liquid crystal has a low molecular weight ferroelectric liquid crystal layer structure, so that the alignment stability is lower than that of the liquid crystal display device using a nematic liquid crystal. Further, uniform alignment is difficult, and the contrast is lower than that of a liquid crystal display element using a nematic liquid crystal.

On the other hand, an alignment film subjected to orientation treatment by the rubbing method is used for orienting the low-molecular ferroelectric liquid crystal.

Further, HV (Half-V) mode and V-mode liquid crystal display devices have been proposed which consecutively continue display by sacrificing the bistability of a liquid crystal display element of SS-FLC mode using a low-molecular ferroelectric liquid crystal (for example, Patent Document 2). The H-V mode and V mode liquid crystal display devices using this low-molecular ferroelectric liquid crystal are intended for high-speed response of a liquid crystal display device using a nematic liquid crystal.

The liquid crystal display device of the H-V mode and the V mode using the low-molecular ferroelectric liquid crystal can improve the response speed as compared with the liquid crystal display device using the nematic liquid crystal. Further, the liquid crystal display elements of the H-V mode and the V mode using the low-molecular ferroelectric liquid crystal perform continuous gradation display with bistability.

In addition, the liquid crystal display devices of the H-V mode and the V mode using the low-molecular ferroelectric liquid crystal have a layered structure of the low-molecular ferroelectric liquid crystal, and thus the alignment stability is lower than that of the liquid crystal display device using the nematic liquid crystal. Further, uniform alignment is difficult, and the contrast is lower than that of a liquid crystal display element using a nematic liquid crystal.

Further, in order to improve alignment stability in a liquid crystal display device of SS-FLC mode using a low-molecular ferroelectric liquid crystal, a liquid crystal display device of SS-FLC mode using a polymer ferroelectric liquid crystal has been proposed (see, for example, Patent Documents 3 to 7 ).

The liquid crystal display device of the SS-FLC mode using the polymer ferroelectric liquid crystal has two substrates facing each other, a transparent electrode formed on each of the substrates facing each other, and a liquid crystal layer formed by the polymer ferroelectric liquid crystal injected between the substrates have. Here, the liquid crystal layer is subjected to an orientation treatment by a shearing method (Zygawa method) in which a polymer ferroelectric liquid crystal is oriented by applying a shear stress to the substrate when a voltage is applied between the substrates.

The SS-FLC mode liquid crystal display device using the polymer ferroelectric liquid crystal can realize the same response speed as the liquid crystal display device using the nematic liquid crystal. However, since the liquid crystal display device has a high molecular weight and a high viscosity, Is delayed.

In addition, since the SS-FLC mode liquid crystal display device using the polymer ferroelectric liquid crystal has a principle of bistability, the continuous gradation display can not be simply performed. In order to perform continuous gradation display, the area gradation, domain gradation, It is necessary to apply a technique such as gradation. In this case, there is a problem that the structure becomes complicated or the cost becomes high.

In addition, the SS-FLC mode liquid crystal display device using the polymer ferroelectric liquid crystal has a layered structure of the polymer ferroelectric liquid crystal, so the alignment stability is lower than that of the liquid crystal display device using a nematic liquid crystal. However, The orientation stability is higher than that of the display element.

Further, since the polymer ferroelectric liquid crystal has a layered structure, it is difficult to uniformly orient the liquid crystal display device and contrast of the liquid crystal display device using nematic liquid crystal can not be obtained. In addition, since the molecular weight is large, it is difficult to obtain a uniform orientation by the rubbing method, and the alignment process is carried out by a shearing method (zigzag method) in which the process is complicated.

Further, the liquid crystal display device using the conventional nematic liquid crystal described above, the liquid crystal display device using the low molecular ferroelectric liquid crystal (SS-FLC mode, HV mode, V mode) and the liquid crystal display device using the polymer ferroelectric liquid crystal Method) does not have a continuous gradation memory property in which the gradation state is held (memorized) when the voltage is turned off while performing continuous gradation display.

(Potential curve) between the orientation angle (the orientation angle varies depending on the voltage application) and the potential in the liquid crystal display elements capable of continuous gradation display (for example, nematic liquid crystal, HV mode and V mode) It is largely influenced by the orientation treatment by the rubbing method.

Further, in the liquid crystal display element of the SS-FLC mode using the low-molecular ferroelectric liquid crystal or the polymer ferroelectric liquid crystal having bistability, the liquid crystal molecules move to the bistable position by the application of the voltage. In the SS-FLC mode using the low-molecular ferroelectric liquid crystal or the polymer ferroelectric liquid crystal, the principle of the conventional liquid crystal display element can not memorize the gradation state at the intermediate gradation from the relation between the orientation angle and the potential.

For this reason, in the conventional liquid crystal display device, there is a problem that continuous gradation memory performance in which the gradation state is retained (memory) when the voltage is turned off can not be realized while performing continuous gradation display. Thus, it has been proposed to realize continuous gradation memory performance by applying domain gradation (see, for example, Non-Patent Document 1).

In view of the above, the applicant of the present invention has proposed a liquid crystal display device which has the same display characteristics as a liquid crystal display device using a nematic liquid crystal, which is widely used, and which can realize continuous gradation display, Devices have already been proposed. This includes a polymeric ferroelectric liquid crystal as a liquid crystal material sealed between both substrates facing each other.

[Patent Document 1] Japanese Unexamined Patent Application Publication No. 62-131225

[Patent Document 2] Japanese Unexamined Patent Application Publication No. 2004-86116

[Patent Document 3] Japanese Unexamined Patent Application Publication No. 56-107216

[Patent Document 4] Japanese Unexamined Patent Application Publication No. 2-240192

[Patent Document 5] Japanese Unexamined Patent Application Publication No. 2-271326

[Patent Document 6] Japanese Unexamined Patent Application Publication No. 3-42622

[Patent Document 7] Japanese Unexamined Patent Application Publication No. 6-281966

[Non-Patent Document 1] Hideo Fujikake et al, "Polymer-Stabilized Ferroelectric Liquid Crystal Devices with Grayscale Memory ", Jpn.J.Appl.Phys, Vol.36, pp.6449-6454, 1997

However, in a ferroelectric liquid crystal comprising a polymeric ferroelectric liquid crystal as a liquid crystal material sealed between two substrates facing each other, the contrast of the liquid crystal molecules is lower than that of a liquid crystal panel of the TN mode or IPS mode.

Further, since the ferroelectric liquid crystal has a layer structure, it is difficult to align the directions of the liquid crystal molecules in one direction uniformly, and it is difficult to uniformly orient the liquid crystal molecules. Therefore, it is difficult to improve the contrast because there is a large amount of leakage light at the time of black display.

It is an object of the present invention to provide a method for manufacturing a liquid crystal display element using a high-contrast polymer ferroelectric liquid crystal and a liquid crystal display element.

According to another aspect of the present invention, there is provided a method of manufacturing a liquid crystal display device, including forming a first alignment layer and a second alignment layer on the opposite surfaces of a first substrate and a second substrate facing each other, A liquid crystal layer forming step of forming a liquid crystal layer by enclosing a liquid crystal material including a polymeric ferroelectric liquid crystal between a first substrate on which the first alignment film is formed and a second substrate on which the second alignment film is formed, And a step of applying an electric field by quenching with a temperature gradient of 10 [deg.] C / min from the ISO temperature (110 [deg.] C) to the room temperature at a frequency of 50 to 75 Hz after the layer forming step, The firing temperature of the first and second alignment films is 250 to 350 DEG C for 30 minutes.

The liquid crystal display device according to the present invention comprises a first substrate and a second substrate facing each other, a first alignment film formed on each of the opposing surfaces of the first substrate and the second substrate and subjected to alignment treatment by a rubbing method, And a liquid crystal layer formed by encapsulating a liquid crystal material including a polymeric ferroelectric liquid crystal between a first substrate on which the first alignment film is formed and a second substrate on which the second alignment film is formed, The first orientation film and the second orientation film are subjected to electric field application by quenching with a temperature gradient of 10 DEG C / min from the ISO temperature (110 DEG C) to the room temperature, and the first orientation film and the second orientation film have a sintering temperature of 250 DEG C to 350 DEG C Lt; 0 > C for 30 minutes.

The method for manufacturing a liquid crystal display element and the liquid crystal display element according to the present invention have the following effects.

First, a high contrast can be obtained by baking in the range of 230 ° C to 350 ° C as the baking temperature of the orientation film.

Second, the first and second alignment films are formed so as to satisfy the relationship of the inter-polyimide spacer length of the alignment film on either side of the first and second alignment films = the inter-polyimide spacer x 2.5 x n (n is a positive integer of 0 or more) A high contrast can be obtained.

Third, a high contrast can be obtained by performing the electric field application process by forming the liquid crystal layer and then quenching at the ISO temperature.

1 is a cross-sectional view showing a configuration of a liquid crystal display element according to the present invention
Fig. 2 is a diagram illustrating the twist state and the uniform state in the ferroelectric liquid crystal
Fig. 3 is a diagram showing the relationship between frequency and contrast (CR)
4 is a graph showing the relationship between the electric field application start temperature, the temperature gradient and the contrast enhancement

Best Mode for Carrying Out the Invention Hereinafter, preferred embodiments of a method of manufacturing a liquid crystal display element according to the present invention will be described with reference to the drawings, wherein like or corresponding parts are denoted by the same reference numerals.

1 is a cross-sectional view showing a configuration of a liquid crystal display element according to the present invention.

1, a liquid crystal display device according to the present invention includes a first substrate 1, a second substrate 2, a first transparent electrode 3, a second transparent electrode 4, a first alignment film 5, a second alignment film 6, a liquid crystal layer 7, and a substance 8.

The first substrate 1 and the second substrate 2 facing each other are glass substrates and the liquid crystal layer 7 is formed between the first substrate 1 and the second substrate 2 by a liquid crystal material containing a polymeric ferroelectric liquid crystal A material is sealed and formed.

Here, the liquid crystal material is a mixture of a polymeric ferroelectric liquid crystal or a polymeric ferroelectric liquid crystal and a low molecular liquid crystal. Light from a backlight (not shown), which is formed on the first substrate 1 on the side opposite to the liquid crystal layer 7 of the first substrate 1 and functions as a light source, is incident.

The first transparent electrode 3 is formed on the surface of the first substrate 1 facing the second substrate 2. The second transparent electrode 4 is formed on the surface of the second substrate 2 facing the first substrate 1. The first transparent electrode 3 and the second transparent electrode 4 constitute a pixel electrode and a counter electrode, respectively, and generate an electric field in a direction perpendicular to the first substrate 1 and the second substrate 2.

The first alignment layer 5 is formed on the first transparent electrode 3 of the first substrate 1 and subjected to alignment treatment by the rubbing method. The second alignment film 6 is formed on the second transparent electrode 4 of the second substrate 2 and subjected to orientation treatment by the rubbing method. So that the liquid crystal layer 7 is oriented in the direction perpendicular to the rubbing direction.

Next, a manufacturing procedure of the liquid crystal display element according to the present invention will be described.

First, a first transparent electrode 3 and a TFT (Thin Film Transistor, not shown) are formed on a first substrate 1 by sputtering or the like. In addition, a color filter (not shown) is formed on the second substrate 2, and a second transparent electrode 4 is formed on the color filter.

Subsequently, after the first substrate 1 and the second substrate 2 are cleaned, the first transparent electrode 3 and the TFTs on the first substrate 1 and the second transparent substrate 2 on the second substrate 2 are cleaned, Polyimide is applied as an alignment film on the electrode 4, respectively. The polyimide is spin-coated on a substrate having a transparent electrode formed thereon to a thickness of 1000 angstroms.

Next, the first substrate 1 and the second substrate 2 coated with polyimide are pre-baked and main cured, and then baked at a temperature of 230 to 350 占 폚 And the alignment treatment is carried out by the rubbing method to form the first alignment film 5 and the second alignment film 6. Then,

Table 1 shows the relationship between the firing temperature of the alignment film and the contrast when firing at a high temperature in a nitrogen atmosphere. Here, the contrast is given as brightness at the time of white display / brightness at the time of black display.

Firing temperature ℃ 150 230 300 350 360 Contrast 90 145 310 330 X

As shown in Table 1, the contrast is low at a firing temperature of, for example, 150 캜 or lower, and the orientation film is decomposed at 360 캜 exceeding 350 캜. From such a viewpoint, the firing temperature of the alignment film which obtains sufficiently high contrast is most preferably in the range of 230 ° C to 350 ° C.

Subsequently, after the first substrate 1 and the second substrate 2 are cleaned, the substance 8 is applied to the peripheral portion of the first substrate 1, and the first substrate 1 and the second substrate 2 ). Next, a liquid crystal material in which a polymer ferroelectric liquid crystal and a low molecular weight liquid crystal are mixed is injected and sealed between the bonded first and second substrates 1 and 2 to form a liquid crystal layer (7).

Here, mixing of the polymer ferroelectric liquid crystal and the low molecular weight liquid crystal is to lower the viscosity of the liquid crystal material to improve the response speed and widen the operable temperature range. At this time, only the polymer ferroelectric liquid crystal may be used as the liquid crystal material.

Instead of injecting the liquid crystal material between the bonded first and second substrates 1 and 2, before the first substrate 1 and the second substrate 2 are bonded to each other, It is also preferable to drop the liquid crystal material onto the coated first substrate 1. The charging time of the liquid crystal can be shortened by dropping the liquid crystal material.

Subsequently, the liquid crystal display element provided with the liquid crystal layer 7 was subjected to an aging treatment in which the frequency was 50 to 75 Hz and the temperature was rapidly cooled from the International Organization for Standardization (ISO) temperature (110 DEG C) An electric field application process) is performed to align the ferroelectric liquid crystal to either of the bistable positions. At this time, the temperature gradient is set at 10 占 폚 / min. By performing the electric field application process based on the predetermined gradient of the temperature gradient, the special alignment treatment of the polymer ferroelectric liquid crystal becomes unnecessary.

Meanwhile, in the SS-FLC mode liquid crystal display device using the conventional polymer ferroelectric liquid crystal as described above, a complicated process of orienting the polymer ferroelectric liquid crystal by applying shear stress while applying voltage to the liquid crystal display element at the time of aging is required. In the liquid crystal display element according to Embodiment 1 of the present invention.

In the embodiment of the present invention, the first alignment film 5 and the second alignment film 6 are combinations of different kinds of alignment films satisfying the following relational expression.

That is, the spacer length between the polyimide (hereinafter referred to as the polyimide) of the alignment film on one side of the first alignment film 5 and the alignment film 6 of the other side of the second alignment film 6 is equal to the spacer spacing of 2.5 x n (n Is a positive integer of 0 or more).

A specific combination of alignment films is as follows.

In the combination of the alignment films as shown in Table 2, the following cell was formed and the contrast was measured.

Alignment film B Inter-alignment spacer length Orientation film A Inter-alignment spacer length RN1322 0.2 RN1322 0.2 RN1322 0.2 RN1744 0.5 RN1322 0.2 RN2320 0.7 RN1322 0.2 RN1199 1.0

On the other hand, in Table 2, the alignment film A is used as the second alignment film 6 on the second substrate 2 side while the alignment film B is used as the first alignment film 5 on the first substrate 1 side.

Celling conditions:

Alignment film thickness: 1000 Å, firing temperature: 230 ° C × 20 min, rubbing direction: anparallel, cell gap: 2 μm, contrast is given as brightness at back display / brightness at black display. As a result of contrast measurement, Table 3 can be obtained.

Orientation film name RN1322 RN1744 RN2320 RN1199 Inter-alignment spacer length 0.2 0.5 0.7 1.0 Contrast 290 437 86 426

From the results of Table 3, it can be understood that the contrast increases greatly when the spacer length between the PIs of the second alignment film 6 on the second substrate 2 side is 0.5 and 1.0. From the above, the following relationship is established between the PI spacer lengths of the alignment film A and the alignment film B:

Relational expression: Length of spacer between PIs of alignment film A = Length of spacer between PIs of orientation film B x 2.5 x n (n is a positive integer of 0 or more)

From Table 3, when the contrast is greatly increased, the calculation result is as follows.

0.5 (PI spacer length of orientation film A) = 0.2 (PI spacer length of orientation film B) 2.5 (integer) x 1 (integral multiple)

1.0 (PI spacer length of orientation film A) = 0.2 (PI spacer length of orientation film B) 2.5 (integer) x 2 (integer multiple)

When the substrates facing each other with respect to the ferroelectric liquid crystal panel are the same type of alignment films, the contrast may be lowered.

That is, in the ferroelectric liquid crystal, as shown in Fig. 2, the alignment state does not become uniform, and the contrast is maximized. However, when the same kind of alignment film is used for the upper and lower substrates, And when it is in the Twist state, a phase difference is generated and the contrast is lowered.

In the present invention, the upper and lower substrates have different kinds of alignment films, and the combination satisfies the above-mentioned relational expression, whereby the contrast can be greatly improved.

In a conventional method of applying an electric field to a ferroelectric liquid crystal polymer, the orientation of the liquid crystal molecules is not uniform because the conditions are not optimized, and uniform orientation is not obtained. Therefore, the contrast can not be greatly improved.

In the present invention, the optimum conditions for the contrast in the polymeric ferroelectric liquid crystal were determined by the following conditional expression.

Celling conditions:

Cells having an orientation film thickness of 1000 Å, a firing temperature of 230 캜 20 min, a direction of rubbing: a paralle, and a cell gap of 2 탆 were prepared, and the contrast after the liquid crystal substitution value was set to 1 . The contrast is given by the brightness at the time of white display / the brightness at black display.

Influence of electric field

Electric field: AC (50 Hz) / DC, voltage: 20/50/70 V, and application time: 5/10/30 min. The experimental results are shown in Table 4.

The applied voltage (V) Application time (min) 5 10 30
DC
20 1.20 1.17 1.15 50 1.18 1.11 1.12 75 1.21 1.15 1.12
AC
20 1.20 1.24 1.15 50 1.32 1.55 1.53 75 1.72 2.44 2.40

As shown in Table 4, the DC voltage and the application time vary, and the contrast enhancement rate is about 120%, which is almost constant. The contrast is improved to such an extent that the AC voltage is high, and the contrast can not be improved by 240% at ± 75 V × 10 min and at an application time of 10 min or more.

[Influence of frequency]

AC ± 75V / frequency: 20/50/62.5/75/100 Hz. As shown in FIG. 3, the contrast enhancement rate becomes 240% at a frequency of 50 to 75 Hz and becomes the maximum.

[Influence of start temperature / temperature gradient]

Electric field application temperature: smC (60 占 폚) / smA (95 占 폚) / ISO (110 占 폚)

Temperature gradient: quenching (10 캜 / min) tempering (2 캜 / min)

As shown in Fig. 4, when the temperature is rapidly cooled from the ISO temperature, the contrast (CR) improvement becomes maximum at 1500%.

[theorem]

From these experimental results, it is shown below that the optimum condition for maximizing the contrast (CR) for the polymeric ferroelectric liquid crystal is as follows.

AC ± 75 V, frequency: 50 to 75 Hz, application time: 10 min or more, electric field application start temperature: 110 ° C. (ISO), temperature gradient: 10 ° C./min

As described above, the contrast is remarkably improved by optimizing the electric field application conditions. Particularly, the temperature lowering gradient is quenched in the quenching, whereby the contrast is greatly improved.

1: first substrate 2: second substrate
3: first transparent electrode 4: second transparent electrode
5: first alignment layer 6: second alignment layer
7: liquid crystal layer 8:

Claims (12)

An orientation film forming step of forming a first orientation film and a second orientation film which are subjected to orientation treatment by rubbing on the respective opposing faces of the first substrate second substrate facing each other,
A liquid crystal layer forming step of forming a liquid crystal layer by sealing a liquid crystal material including a polymeric ferroelectric liquid crystal between a first substrate on which the first alignment film is formed and a second substrate on which the second alignment film is formed,
And performing an electric field application process by quenching with a temperature gradient of 10 [deg.] C / min from an ISO temperature (110 [deg.] C) to a room temperature at a frequency of 50 to 75 Hz after the liquid crystal layer formation step,
Wherein the alignment film forming step is a step of firing the first and second alignment films at a temperature of 250 ° C to 350 ° C for 30 minutes in a nitrogen atmosphere or an air atmosphere. delete delete The method for manufacturing a liquid crystal display element according to claim 1, wherein the liquid crystal material is only the polymer ferroelectric liquid crystal. The method of manufacturing a liquid crystal display element according to claim 1, wherein the liquid crystal material is a mixture of the polymeric ferroelectric liquid crystal and a low molecular weight liquid crystal. delete delete delete A first substrate and a second substrate facing each other,
A first alignment layer and a second alignment layer which are respectively formed on the opposing surfaces of the first substrate and the second substrate and are subjected to alignment treatment by a rubbing method,
And a liquid crystal layer formed by encapsulating a liquid crystal material including a polymeric ferroelectric liquid crystal between a first substrate on which the first alignment film is formed and a second substrate on which the second alignment film is formed,
The liquid crystal layer is subjected to an electric field application by quenching with a temperature gradient of 50 to 75 Hz and a temperature gradient of 10 DEG C / min from the ISO temperature (110 DEG C) to the room temperature,
Wherein the first alignment film and the second alignment film are fired in a nitrogen atmosphere or an atmospheric atmosphere at a firing temperature of 250 ° C to 350 ° C for 30 minutes. The liquid crystal display element according to claim 9, wherein the liquid crystal material is only the polymer ferroelectric liquid crystal. The liquid crystal display element according to claim 9, wherein the liquid crystal material is a mixture of the polymeric ferroelectric liquid crystal and the low molecular weight liquid crystal. delete

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