JP2848853B2 - Liquid crystal display device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a liquid crystal display device which performs multi-color display using liquid crystal, and includes a portable television, a small measuring instrument, a portable computer, a decorative display, and the like. Can be used as a color display device.

(Background technology)

2. Description of the Related Art Conventionally, a display element using liquid crystal can be made thin and lightweight, and thus has been frequently used for a display portion of a portable device.

The liquid crystal display element is formed, for example, by sealing a liquid crystal material between a pair of glass substrates or the like having thin-film transparent electrodes on the surface to form a liquid crystal cell, and sandwiching the liquid crystal cell between a pair of polarizing plates. The liquid crystal uses the fact that the polarization axis (amplitude direction) of the light passing through the liquid crystal portion is changed by the arrangement of the liquid crystal molecules, and that the arrangement direction of the liquid crystal molecules can be controlled according to the application of a voltage to the electrodes. By switching the polarization axis of the light from one polarizing plate in the cell so as to be in a direction that allows or cannot pass through the other polarizing plate, the transmitted light is intermittently displayed so that the display can be visually recognized from the outside.

In such a liquid crystal display element, a plurality of liquid crystal cells are stacked to improve the overall contrast, and different types of liquid crystal materials are stacked to improve an operating temperature range. .

On the other hand, in recent years, many portable televisions and the like have been provided with color display, and large-screen display elements and the like have been used for street advertisements, and color liquid crystal display elements have been used as display portions thereof.

As such a color liquid crystal display element, a single-color or two-color display using a guest-host (GH) method has been conventionally known. In addition, a color filter or the like is used to color transmitted light shutter-controlled by the liquid crystal display element. The scheme is known.

For example, in the same way as a normal CRT, a three-primary-color filter in which the transmission colors of minute sections corresponding to the pixels of each cell are the three primary colors of light is arranged on the front of the liquid crystal cell, and three pixels of the element are one pixel of a color image. There is one that realizes a full-color display of an RGB synthesis type (Japanese Patent Application Laid-Open No. Sho 59-170882).

A color display using a color polarizer instead of a color filter is also known.For example, a color polarizer is disposed on the frontmost polarizer among polarizers interposed on both outer sides and an intermediate portion of a liquid crystal cell. There is one that realizes a color display by using the method (Japanese Patent Application Laid-Open No. 56-121076).

Liquid crystal cells used in these color liquid crystal display elements are required to have little basic coloring to transmitted light, and to be stable and high speed in operation. Conventionally, TN (twisted nematic) type liquid crystal cells and STN (STN) Super T
N) type liquid crystal cells are frequently used.

[Problems to be solved by the invention]

However, among the above-mentioned color liquid crystal display elements, in the case of using a color filter, it is necessary to form minute sections colored in each color on the color filter, and in the step of matching each section of the filter to each pixel of the liquid crystal cell. High precision is required. Furthermore, since one of the three primary colors is displayed for each pixel, three pixels of the cell are required for one pixel of the image, and the pixel position for each color is slightly shifted when displaying the intermediate color. And it becomes difficult to display finely.

In the case of using a color polarizing plate, in the case of a color mosaic, in addition to the same problem as in the case of the above-described filter, when the color polarizing plate is arranged on the foreground, even in a non-display state in segment display or pattern display. The display color becomes visible and cannot be used for unexpected advertisement display or the like.

Furthermore, the TN or STN type liquid crystal cell generally used for these color liquid crystal display elements has a slow electric field response, and a general multilayer structure of a glass substrate has a large thickness, and the visual dependency is increased. There was a problem that it was difficult to see.

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid crystal display device which can perform multicolor display with one pixel, has high contrast, and has a high response speed.

[Means for solving the problem]

According to the present invention, a set of three primary color light emitting points is regarded as one pixel so as to be so-called parallel synthesis because a color display such as a normal CRT is an active display.
In contrast to the parallel composition method of each color pixel similar to T, the color liquid crystal, which is a passive display, intermittently or colors transmitted light, so that light is sequentially transmitted through the liquid crystal cell, filter, and polarizing plate, so to speak. This is based on the knowledge that colors can be sequentially superimposed and displayed in multiple colors by serial synthesis.

That is, in the present invention, a plurality of liquid crystal cells are stacked, a polarizing plate is disposed outside the stacked body and between the liquid crystal cells, and a black polarizing plate is used for at least one of these polarizing plates. A liquid crystal display element using a color polarizing plate as one sheet, wherein the liquid crystal cell includes a pair of flexible plastic substrates facing each other, and an electrode provided on each of opposing surfaces of these plastic substrates. And a ferroelectric liquid crystal material sandwiched between these electrodes, and subjected to an orientation treatment by bending deformation, the ferroelectric liquid crystal material is a cross-linkable resin and an adhesive It contains at least one of them and a ferroelectric polymer liquid crystal, and the entirety including the liquid crystal cell and the polarizing plate has flexibility.

Here, as the ferroelectric polymer liquid crystal contained in the ferroelectric liquid crystal material used in the present invention, for example, a polyacrylate-based, polyether-based, polysiloxane-based, polyester-based, repeating unit of each of these systems is used. And the like.

Also, for example, DOBAMBC (p
Low molecular ferroelectric liquid crystal such as -decioxybenzylidene-p'-amino-2-methylbutylcinnamate);
A liquid crystal polymer having a molecular weight of 1,000 or more may be contained.

As the electrodes and substrates constituting the liquid crystal cell, those in which thin-film transparent electrodes are formed on the surface of a flexible transparent plastic substrate can be used, and existing polarizing plates having the necessary color characteristics can be used. .

[Action]

In the present invention, the transmission state of each liquid crystal cell is adjusted by the combination of a plurality of stacked liquid crystal cells and polarizing plates to control the coloring state of the polarizing plate corresponding to each cell. That is, by applying a voltage to a liquid crystal cell corresponding to a polarizing plate of a desired color with respect to transmitted light, each color set for each polarizing plate is selected, and coloring by a plurality of cells and a polarizing plate is simultaneously selected. The transmitted light is sequentially colored at the time of each passage, so that color synthesis can be performed. Therefore, in the liquid crystal display device of the present invention, a plurality of colors are all uniformly applied to the transmitted light, and a full-color display can be performed with one pixel of the liquid crystal cell. In addition, by setting black on one of the polarizing plates, it is possible to enhance the overall contrast of transmitted light, and by using a ferroelectric liquid crystal material for each liquid crystal cell, high-speed response is ensured. Thereby, the above object is achieved.

Furthermore, since the liquid crystal cell is aligned by bending deformation using a flexible plastic substrate, the alignment operation is simple and the alignment can be easily controlled, so that the productivity can be significantly improved.

Further, since the ferroelectric liquid crystal material contains a ferroelectric polymer liquid crystal, a good alignment can be obtained even by a simple bending alignment treatment.

Further, since the entire liquid crystal display element including the liquid crystal cell and the polarizing plate has flexibility, the element can be curved, so that the present invention can be applied to a curved display portion and a portion subjected to bending.

Furthermore, in the present invention, since the ferroelectric liquid crystal material contains either a crosslinkable resin or an adhesive, it is possible to improve the orientation to the bending orientation treatment and to improve the mechanical strength of the entire device. As a result, it is possible to ensure excellent strength to withstand deformation.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1 and 2 show a first embodiment according to the present invention. In the liquid crystal display device 1 of the present embodiment, two liquid crystal cells 10A and 10B are connected to a red polarizing plate 2 and a normal black polarized light. Plate 3 and a blue polarizing plate 4 between cells 10A and 10B.
Is interposed.

Here, the polarizing plates 2 and 4 each selectively show a polarization characteristic with respect to a region excluding red or blue, and change from a transparent state to a colored state of red or blue. It is a normal one that shows polarization characteristics in the region. Further, as shown in FIG. 3, these polarizing plates 2, 3, and 4 are arranged such that their polarization axes 2A, 3A, and 4A are in the same direction (parallel Nicol).

On the other hand, each of the liquid crystal cells 10A and 10B has substantially the same configuration, and among them, the liquid crystal cell 10A will be described. A strong and transparent substrate 11A, 12A using a thin plastic plate is used. It is constituted by sandwiching a liquid crystal layer 13A made of an alignment film of a dielectric polymer liquid crystal.

On these substrates 11A and 12A, stripe-shaped transparent electrodes 14A and 15A are arranged in parallel on each surface, and these electrodes 14A and 1A are arranged in parallel.
5A are arranged orthogonally so as to form a lattice shape, and the liquid crystal cells 10A and 10B are configured to be able to display an image by a matrix in which the liquid crystal layer 13A of the portion sandwiched between the intersections of the electrodes 14A and 15A as one pixel. ing.

Here, the electrodes 14A and 15A are made of indium oxide (In ₂ O) mixed with a trace amount of tin oxide (SnO ₂ ) by sputtering or the like.
₃ ) A transparent and conductive thin film (ITO film) is formed, divided into a plurality of pieces by etching or the like, and shaped into stripes.

Further, the liquid crystal layer 13A is, for example, on the surface of one substrate 11A, a ferroelectric liquid crystal over the electrode 14A from 0.5 to 0.5 by a coating method or the like.
It is formed into a film having an appropriate thickness of about 4 μm.

Note that each of the liquid crystal cells 10A and 10B has an angle θ of 22.5 ° in a liquid crystal alignment processing direction (layer normal direction) of each of the liquid crystal layers 13A and 13B.
As shown in FIG. 3, the respective alignment directions 16A and 16B are inclined by the alignment processing angle θ = 22.5 ° with respect to the directions of the respective polarization axes described above, and the long axis of the liquid crystal molecules of each of the liquid crystal cells 10A and 10B. The directions 17A and 17B are set so as to face the same 0 ° direction as the reference direction by the application of the voltage + V, and to have an inclination of 2θ = 45 ° with respect to the reference direction by the application of the voltage −V.

In such a configuration, white illumination light 20 is applied to the liquid crystal display element 1 from the polarizing plate 2 side, and the birefringence characteristics of each of the liquid crystal cells 10A and 10B are changed according to the applied voltage ± V. By controlling the transmission states of the red polarizing plate 2 and the blue polarizing plate 4 corresponding to 10A and 10B, the transmitted light 21 passing through the black polarizing plate 3 is colored for each pixel, and a four-color image is displayed.

That is, when a display signal voltage + V is applied between the electrodes 14A and 15A and between the electrodes 14B and 15B, as shown in FIG. 4, the liquid crystal molecules 13A and 13B have their liquid crystal molecule long axis directions 17A and 17B in their respective orientations. Rotating clockwise from the directions 16A and 16B by the tilt angle θ and maintaining the reference direction at 0 °, the red polarizing plate 2 and the liquid crystal cell 10
A, the polarizing axes reaching the blue polarizing plate 4, the liquid crystal cell 10B, and the black polarizing plate 3 are all in the same direction, that is, transparent, and the illumination light 20 incident from the polarizing plate 2 passes through each part as it is and is generated on the polarizing plate 3 side. The transmitted light 21 is white light.

Next, the electrodes 14A, 15A are kept at the voltage + V between the electrodes 14B, 15B.
When a voltage -V is applied with the polarity of the liquid crystal layer 13A reversed, the long axis direction 17A of the liquid crystal molecules of the liquid crystal layer 13A is rotated counterclockwise by 2θ and maintained at 45 ° with respect to the reference direction, as shown in FIG. Is done. Therefore, the polarization component 22 of the incident illumination light 20 due to the red polarizing plate 2 is rotated from the 0 ° direction to the 90 ° direction by the birefringence in the liquid crystal cell 10A, and cannot pass through the blue polarizing plate 4. At this time, the polarized light component 22 polarized by the red polarizer 2 is a region excluding red, and only the unpolarized red is the blue polarizer 4 or subsequent liquid crystal cells 10B,
The light passes through the black polarizing plate 3. Therefore, the transmitted light in this state
21 turns red.

On the other hand, while the voltage between the electrodes 14A and 15A is + V, the electrodes 14B and 15B
When the voltage -V is applied with the polarity of the liquid crystal layer 13B reversed, the liquid crystal layer major direction 17B of the liquid crystal layer 13B rotates counterclockwise by 2θ and is maintained at 45 ° with respect to the reference direction, as shown in FIG. Is done. For this reason, the incident illumination light 20 passes through the red polarizing plate 2, the liquid crystal cell 10A, and the blue polarizing plate 4, but the polarized light component 24 of the blue polarizing plate 4 causes the polarization axis of the liquid crystal cell 10B to move in the direction of 0 ° due to birefringence. , And cannot pass through the blue polarizing plate 4. At this time, the polarized light component 24 polarized by the blue polarizing plate 4 is a region excluding blue, and only the unpolarized blue passes through the black polarizing plate 3. Therefore, the transmitted light 21 in this state is blue.

Further, when a voltage -V is applied between the electrodes 14A and 15A and between the electrodes 14B and 15B, as shown in FIG. 7, the liquid crystal molecule major axis directions 17A and 17B of the liquid crystal layers 13A and 13B respectively correspond to the reference directions. The illumination light 20 is maintained at 90 ° with respect to the red polarizer 2,
The liquid crystal cell 10A receives red coloring while reaching the blue polarizing plate 4, and the blue polarizing plate 4, the liquid crystal cell 10B, and the black polarizing plate 3
, And the transmitted light 21 generated on the polarizing plate 3 side becomes violet light due to superposition of red and blue.

According to this embodiment, red or blue coloring according to the polarizing plates 2 and 4 can be controlled by the voltage applied to each of the liquid crystal cells 10A and 10B, and the white illumination light 20 can be appropriately adjusted. It is possible to display four colors such as red, blue, purple colored by combining these, or uncolored white.

Table 1 shows changes in the color of the transmitted light 21 depending on the combination of these applied voltages.

The coloring of the transmitted light 21 is performed in such a manner that red coloring and blue coloring are sequentially performed in series.
Four colors can be displayed for each pixel.

For this reason, one pixel of the liquid crystal display element 1 can be directly used as one pixel of a color image, and the resolution can be increased as compared with the conventional case where a plurality of pixels for each color are used as a set, and Since the display image does not blur by color, extremely fine display can be performed.

In addition, when a plurality of pixels for each color are used, a mosaic-type color filter or the like is not required, and a step of coloring each fine section required for its manufacture can be omitted, and the position of the pixel of the liquid crystal cell and the colored section can be eliminated. The alignment and the like can be omitted, and the production can be performed extremely easily.

Furthermore, since the ferroelectric liquid crystal material is used for the liquid crystal cells 10A and 10B, the electric field response to the applied voltage can be sped up, and the follow-up performance can be improved even when displaying a moving image on a television or a real-time display of a measuring instrument. Thus, the accuracy and visibility of the image can be improved.

In addition, since a flexible thin plate is used for the substrates of the liquid crystal cells 10A and 10B, the liquid crystal display element 1 can be appropriately curved, and can be applied to a curved display portion or a portion which is to be bent. Can be.

FIG. 8 shows a second embodiment of the present invention in contrast to the first embodiment. In this embodiment, as the liquid crystal display element 80, a blue polarizing plate 81, a liquid crystal cell 82, a green polarizing plate 83, a liquid crystal cell 84, a red polarizing plate 85, a liquid crystal cell 86, and a black polarizing plate 87 are sequentially laminated. Here, each liquid crystal cell 82,8
4, 86 have the same configuration as the liquid crystal cell 10A of the above embodiment.

According to this embodiment, the same effects as those of the first embodiment can be obtained. In addition, the three liquid crystal cells 82, 84, 86 provide blue, green, and red ( Color display can be performed by combining the three primary colors of light (RGB).

For this reason, in addition to the individual coloring of each of the RGB colors, by simultaneously performing arbitrary coloring, it is possible to perform synthetic coloring of intermediate colors such as sky blue, yellow, and purple.

In particular, the composition ratio of the intermediate colors can be adjusted by the voltage applied to each liquid crystal cell, and the RGB composite color tone can be delicately changed over a wide range, so that a so-called full-color display can be realized.

Further, in addition to full-color display by RGB synthesis, matrix-type image display can be performed by cross-arranged striped electrodes, so that full-color image display similar to RGB synthesis in a normal CRT can be performed.

For this reason, even with a simple pattern display, visibility can be improved by using various color tones, which is suitable for an advertising light, a decorative panel, and the like.

Further, in the present embodiment, RGB synthesis can be performed with one pixel, so that the definition of an image can be enhanced even in the case of full-color display, and the display can be performed at high speed by using a ferroelectric liquid crystal. Full-color accurate display can be performed even for moving images and images that change rapidly.

In each of the above embodiments, the parallel Nicols in which the polarization axes of the respective polarizing plates are all aligned with the reference direction are used. However, they may be arranged in a crossed arrangement (crossed Nicols) rotated sequentially by 90 degrees. In this case, the alignment direction of each liquid crystal cell may be appropriately adjusted and rearranged so as to obtain an intended coloring function.

Further, in each of the above embodiments, a configuration in which two colors of red and blue are colored by two liquid crystal cells and three polarizing plates, and
The configuration for performing RGB combined full-color display using three liquid crystal cells and four polarizing plates has been described. However, the order of each color of these polarizing plates may be arbitrary, and the coloring color in each of them is appropriately selected by changing the polarizing plate. do it.

Furthermore, even if it is configured so that display of four or more colors can be performed by four or more liquid crystal cells and the polarizers on the outside and on both sides of the liquid crystal cells, in other words, between the cells of the stacked body of a plurality of liquid crystal cells and Arrange polarizing plates on both outer sides of the laminate,
At least one of these polarizing plates may be a color polarizing plate, and one may be a black polarizing plate.

On the other hand, the liquid crystal cells used for the liquid crystal display element do not need to be all the same, and may be appropriately selected in implementation, such as using a different type of liquid crystal material according to the color or brightness to be colored.

Further, for the substrate of the liquid crystal cell, polyethylene terephthalate, polymethyl methacrylate, polycarbonate, or another plastic light-transmitting material can be used.

This substrate is flexible, so that the entire liquid crystal display element can be bent, and the alignment treatment for the liquid crystal material can be performed by bending.

In addition, as a transparent electrode formed on the substrate surface, ITO
Not only indium oxide (In ₂ O ₃ ) film mixed with tin oxide (SnO ₂ ), which is called film, but also metal oxide film such as tin oxide film called NESA film, near (Au), aluminum (Al),
A metal thin film such as titanium (Ti) may be used. In forming the thin film, not only sputtering but also a direct evaporation method or a spray method may be used. In short, a transparent and conductive thin film which does not hinder light transmission. It is desirable to form

The shape of this electrode is not limited to one in which a plurality of stripe-shaped electrodes arranged in parallel are opposed to each other in the cross direction, and a matrix having pixels at the intersections is formed to enable image display. When used for display, bar graph, or the like, one electrode may be used as a common electrode and the bar-shaped electrodes may be opposed to each other. In the case of displaying only a specific shape and pattern, each electrode may be formed in a planar shape.

In forming a liquid crystal cell using these substrates and electrodes, any method such as an injection method or a coating method can be used.

Here, the liquid crystal layer formed in the liquid crystal cell has a thickness of 0.5
It is preferably in the range of about to 20 μm. This thickness may be appropriately set according to the required optical characteristics, and there is no problem even if the thickness is larger. However, the thickness is preferably about 0.5 to 4 μm because bistability is obtained and the applied voltage can be reduced. Is preferred.

In addition, if necessary, silicon dioxide (Si
O ₂ ) or spherical or fiber spacers such as ceramics and plastics may be used in combination.

Further, as the ferroelectric liquid crystal material used for the liquid crystal layer, a low molecular material may be used together with the ferroelectric polymer liquid crystal. By using a ferroelectric polymer liquid crystal, a mechanical alignment process can be utilized by utilizing its characteristics, and alignment can be easily controlled.

For example, a stretching method and a coating method are suitable for forming a thin film of a ferroelectric polymer liquid crystal, and by appropriately setting a stretching direction or a coating direction when forming a liquid crystal cell, a predetermined alignment treatment can be performed very easily. It can be carried out.

In addition, since the substrate is flexible, an alignment treatment by bending can be performed, and the productivity can be extremely increased in any of a polymer and a low-molecular liquid crystal.

Hereinafter, specific examples of the ferroelectric liquid crystal material applicable to the present invention will be described.

As the ferroelectric liquid crystal material used in the present invention, a ferroelectric polymer liquid crystal or a mixture of a ferroelectric polymer liquid crystal and a ferroelectric low-molecular liquid crystal can be used. Among them, a chiral smectic C phase is preferable. (S _m C ^* phase) is preferred.

Further, in order to improve the alignment, it is desirable that the polymer liquid crystal be contained in 5 mol% or more, preferably 10 mol% or more of the whole liquid crystal material.

The ferroelectric polymer liquid crystal used in the present invention is not particularly limited, and various ones can be used. In general, a polymer compound having a mesogen in a side chain via a spacer can be preferably used.

This side-chain type polymer liquid crystal is composed of three parts of a polymer main chain, a mesogen and a spacer, and examples thereof include those represented by the following general formula (1).

However, in the formula (1), E _a E, _b is a polymer main chain, D is a spacer, and M is a mesogen.
b may be 0, but when b is not 0, the unit of (EDM) and the unit of (E ′) in the formula may be connected at random or in a block. Or may be connected alternately.

As the main chain, various polymer main chains can be used,
Preferred main chains include polyacrylate, polysiloxane, polyether, polyester, polymethacrylate, and the like.

As the spacer D, various spacers can be used, and for example, a spacer represented by the following formula (2) can be preferably used.

COO _m CH _{2 n} (2) In the formula (2), m represents 0 or 1, and n represents an integer of 3 to 30.

As the mesogen M, various types can be used, and for example, those represented by the following formula (3) can be suitably used.

Z _L R ₁ (3) where, (3) where, L is 0 or 1, Z is -0- represents a (oxygen atom) or -COO- (ester bond), -R ₁ is the following (4) Those represented by the following formulas can be suitably used.

However, X in each formula of the above (4) is, for example, -COO-,
Represents -OCO-, -R _2, for example _{-COO-R 3, -OCO-R} 3,
_{-O-R 3, -CO-R} 3, represents a -R _3. The —R ₃ is, for example, a chain or branched alkyl group having 4 to 10 carbon atoms containing an asymmetric carbon atom C ^* , a haloalkyl group containing —Cl or F, —CN.
And a cyanoalkyl group containing

Among these polymer liquid crystals, a ferroelectric polymer liquid crystal having a chiral smectic C phase (S _m C ^* phase) is particularly preferable in terms of electric field response speed, contrast, and the like.

Examples of the ferroelectric polymer liquid crystal having such a chiral smectic C phase include the following polymer liquid crystals [I] to [V]. In addition, these [I]-
The polymer liquid crystal of [V] usually has a chiral smectic C phase in a temperature range from room temperature to about 150 ° C., and is remarkably excellent in response speed, contrast and film-forming properties.

[I] Polyacrylate polymer liquid crystal (Japanese Patent Application No. 61-3052)
No. 51 and Japanese Patent Application No. 62-106353 filed by the present applicant, etc.) Polyacrylate polymers having a repeating unit represented by the following general formula and copolymers thereof.

Integer in the formula, k is from 1 to 30, preferably 4 to 20 integer, Z is -O -, - is COO-, -R ₁ is It is. X is -COO- or -OCO-,
-R ₂ is -COO-R ₃ , -OCO-R ₃ , -OR ₃ or -R ₃ , and -R ₃ is And the like. Where -R ₄ and -R ₅ are -C
H _3, -CN, -F or -Cl, preferably -CH _3, g and h are from 0 to 10 integer, q is 0 or 1, C ^* is an asymmetric carbon atom. However, when the -R ₅ is -CH ₃ is,
h is not zero. Further, as particularly preferred -R _3, Can be mentioned.

It should be noted that a methacrylate polymer is similar to the polyacrylate polymer. Chloroacrylate polymer Also available. These k, Z, -R ₁ have the same meanings as above.

[II] Polyether polymer liquid crystal (such as that filed by the present applicant as Japanese Patent Application No. 61-309466) A polyether polymer having a repeating unit represented by the following general formula and a copolymer thereof.

Wherein, k, -R ₁ have the same meanings as in the polyacrylate.

[III] Polysiloxane polymer liquid crystal (Japanese Patent Application No. 62-11471)
No. 6 filed by the present applicant, etc.) A polysiloxane-based polymer having a repeating unit represented by the following general formula and a copolymer thereof.

Wherein, -R ₆ represents a lower alkyl group, k is an integer of 3 to 30, -R ₁ have the same meanings as in the polyacrylate.

[IV] Polyester polymer liquid crystal (such as that filed by the present applicant as Japanese Patent Application No. 61-206581) A polyester polymer having a repeating unit represented by the following general formula and a copolymer thereof.

Wherein, -R ₇ is -H, a -CH ₃ or -C ₂ H _5, L 1
20 integer, k, -R ₁ have the same meanings as in the polyacrylate.

In addition, as the polyester type, as a specific thing, And the like.

[V] A liquid crystal polymer in which the side chain is fixed to the main chain by hydrogen bonding (which can be inferred from the application filed by the present applicant as Japanese Patent Application No. 61-169288).

 One or more types of side chains may be used.

The number average molecular weight of the polymer liquid crystal used in the present invention as described in [I] to [V] is 1,000 to 1,000,000, preferably 1,000 to 400,000. If it is less than 1,000, the moldability as a polymer liquid crystal film or coating film may be impaired. On the other hand, if it exceeds 400,000, undesired results such as a slow response speed may appear. The particularly preferable range of the number average molecular weight cannot be unconditionally defined because it depends on the type of the substituent and the like.
~ 200,000.

In addition, these polymer liquid crystals may be used in combination of two or more as appropriate as long as the object of the present invention is not hindered.

Further, the high-molecular liquid crystal according to the present invention is a liquid crystal polymer and an olefin-based resin, an acrylic resin, a methacryl-based resin, a polystyrene-based resin, a polyester-based resin, and a polycarbonate, as long as the object of the present invention is not hindered. It is also possible to prepare a polymer liquid crystal film by using a mixture with an ordinary resin such as a base resin, a styrene-butadiene copolymer, or a vinylidene chloride-acrylonitrile copolymer. However, if these resins are added in a large amount, the liquid crystallinity is lowered.

Further, in order to improve the response, a ferroelectric low-molecular liquid crystal, for example, a liquid crystal compound having a chiral smectic C phase such as p-decyloxybenzylidene-p'-amino-2-methylbutylcinnamate (DOBAMBC) is used. They can be used in combination. The mixing ratio is preferably 5 or less by weight.

There is no particular limitation on the method of blending the above components, and they can be blended by a usual method.

In addition, the ferroelectric polymer liquid crystal used in the present invention includes an asymmetric carbon atom C ^{* at} the terminal of the side chain in the polymer ^.
Is not limited to those having one or two asymmetric carbon atoms, and those having three or more asymmetric carbon elements in the terminal portion of the side chain can also be used.

On the other hand, as the ferroelectric low-molecular liquid crystal, the following ones such as DOBAMBC described above can be used.

Examples of the ferroelectric low-molecular liquid crystal compound include Schiff base ferroelectric low-molecular liquid crystal compounds, azo and azoxy ferroelectric low-molecular liquid crystal compounds, biphenyl and aromatics ester ferroelectric low-molecular liquid crystal compounds, and halogens. ,
Ferroelectric low-molecular liquid crystal compounds into which a ring substituent such as a cyano group is introduced, and ferroelectric low-molecular liquid crystal compounds having a heterocyclic ring are exemplified.

Examples of the Schiff base ferroelectric low-molecular liquid crystal compound include the following compounds (1) to (4).

Examples of the azo and azoxy-based ferroelectric low-molecular liquid crystal compounds include the following (5) and (6).

Examples of the biphenyl and aromatics ester-based ferroelectric low molecular weight liquid crystal compounds include the following compounds (7) and (8).

Examples of the ferroelectric low-molecular liquid crystal compound into which a ring substituent such as a halogen or a cyano group is introduced include the following compounds (9) to (11).

As a ferroelectric low-molecular liquid crystal compound having a heterocyclic ring,
For example, the following compounds (12) and (13) can be mentioned.

The compound is a typical ferroelectric low-molecular liquid crystal compound, and the ferroelectric low-molecular liquid crystal compound of the present invention is not limited to these structural formulas.

Furthermore, a non-liquid crystalline polymer is added to the above liquid crystal material in an amount of 0 to 60% by weight in order to improve the mechanical strength of the liquid crystal panel and improve the alignment property against bending alignment treatment. As the polymer to be added, a thermoplastic resin or a crosslinkable resin is used, and an adhesive is particularly preferable.

As the thermoplastic resin, those having a Tg of preferably 30 ° C. or higher, more preferably 70 ° C. or higher are used.

Specifically, polyvinyl chloride, polyvinyl bromide, polyvinyl fluoride, vinyl chloride-vinyl acetate copolymer, vinyl chloride-ethylene copolymer, vinyl chloride-propylene copolymer, vinyl chloride-vinylidene chloride copolymer Copolymer, vinyl chloride-butadiene copolymer, vinyl chloride-acrylate copolymer, vinyl chloride-acrylonitrile copolymer, vinyl chloride-styrene-acrylonitrile terpolymer, vinyl chloride-vinylidene chloride-vinyl acetate copolymer Coal, vinylidene chloride, polytetrafluoroethylene, polytetrafluorochloroethylene, polyvinylidene fluoride and other halogenated vinyl polymers or copolymers; unsaturated alcohols such as polyvinyl alcohol, polyallyl alcohol, polyvinyl ether and polyallyl ether Or the weight of ether Polymer or copolymer of unsaturated carboxylic acid such as acrylic acid or methacrylic acid; unsaturated bond in alcohol residue such as polyvinyl ester such as polyvinyl acetate or polyallyl ester such as polyphthalic acid Having an unsaturated bond between an acid residue or an acid residue and an alcohol residue such as a polymer of polyacrylate, polymethacrylate, maleate or fumarate; Polymers or copolymers of the above; unsaturated nitrile polymers or copolymers such as acrylonitrile or methacrylonitrile polymers or copolymers, polyvinylidene cyanide, malononitrile or fumaronitrile polymers or copolymers; polystyrene, polyα -Methylstyrene, poly p-methylstyrene, Polymers or copolymers of aromatic vinyl compounds such as Tylene-α-methylstyrene copolymer, styrene-p-methylstyrene copolymer, polyvinylbenzene and polyhalogenated styrene; polyvinylpyridine, poly-N-vinylpyrrolidine ,
Polymer or copolymer of a heterocyclic compound such as poly-N-vinylpyrrolidone; polyester condensate such as polycarbonate; polyamide condensate such as nylon 6, nylon 6,6; maleic anhydride, fumaric anhydride and imide thereof Polymer or copolymer containing a compound; heat-resistant organic polymers such as polyamide imide, polyether imide, polyimide, polyphenylene oxide, polyphenylene sulfide, polysulfone, polyether fluorene, and polyarylate.

Embodiment 1 As a first embodiment, a ferroelectric liquid crystal was used. And a epoxy-based adhesive (trade name: Cemedine Super, manufactured by Cemedine Co., Ltd., volume ratio: base agent: hardener = 1: 1) in a ratio of 4: 1 by weight to a dichloromethane solution of 10% by weight, using a direct gravure coater PES substrate with ITO (FST-1351 manufactured by Sumitomo Bakelite Co., Ltd., thickness 100 μm, width
(500 mm), and the solvent was evaporated to form a film of about 3 μm. Next, using a pair of pressure rollers, the substrate was laminated with the same type of substrate on which nothing was applied. Then, it was immediately uniaxially horizontally oriented using a bending orientation apparatus as shown in FIG. The rolls 91, 92 and 93 shown in FIG. 9 are all made of chrome-plated iron having a diameter of 80 mm and a width of 60 mm. The temperature of the roll 91 is T ₁ = 110 ° C., and the temperature of the roll 92 is T ₂ = 97 ° C., the temperature T _{3 of the} roll 93 = 90 ° C., and the feed speed v = 2 m / min. Several minutes after the alignment treatment, after the adhesive was cured, three pieces of 500 mm in length were cut out to obtain a liquid crystal cell. This liquid crystal cell was sandwiched between ordinary black polarizing plates and the contrast was measured. At room temperature (25 ° C), a good value of about 90 was obtained when ± 5 V was applied. Did not change and the bistability was good.

The liquid crystal display device of the second embodiment described above was constituted by using three such liquid crystal cells. At this time, as the polarizing plate,
Panac Industries, Ltd., red polarizing plate: SCC2-R2-12S, green polarizing plate: SCC2-G2-12S, blue polarizing plate: SCC2-B2-12S,
Black polarizing plate: LLC2-9818S was used. The display as shown in Tables 2 and 3 was confirmed by such a liquid crystal display device.

In these tables, V5 indicates the applied voltage of the liquid crystal cell 82, and V6
Indicates a voltage applied to the liquid crystal cell 84. Table 2 shows the case where the applied voltage V7 of the liquid crystal cell 86 is + 5V, and Table 3 shows the case where the applied voltage V7 of the liquid crystal cell 86 is -5V. Further, the numerical value in each parenthesis indicates the transmitted light intensity when the white transmitted light in the transparent state is set to 100.

In this example, the response time at room temperature is 150μ with ± 10V applied.
s.

As a second embodiment, a liquid crystal material is changed to a ferroelectric polymer liquid crystal in order to make the threshold characteristics of the liquid crystal moderate by a manufacturing method similar to that of the first embodiment. 85 vol% and Nippon Aerosol Co. SiO ₂ particles (mean diameter
7 mm) 15% by volume of the mixture. As a result, the threshold characteristics of the liquid crystal cell with respect to the electrolytic strength became moderate, and it was possible to change the alignment direction almost continuously when the applied voltage was between -7 and + 7V.

When the liquid crystal display device of the second embodiment was formed using such a liquid crystal cell, the color tone and the display color tone could be continuously changed by continuously changing the voltage applied to each liquid crystal cell. did it. The transmitted light intensities were almost the same, and 40 or more were always obtained.

At this time, for example, the time required to change from blue to green was 700 μs, and it was confirmed that the time was faster than that of a conventional nematic liquid crystal.

As a comparative example, a liquid crystal display element was manufactured by the same manufacturing method as in the first embodiment, and the same thing as the red polarizing plate 85 was used in place of the lowermost black polarizing plate 87. Table 5 shows the color and transmitted light intensity. Table 4 corresponds to Table 2 above, and Table 5 corresponds to Table 3 above.

From these results, it is clear that in the comparative example, a sufficient change in contrast and clear color tone cannot be obtained as compared with the first embodiment, and a black polarizing plate is used as in the first embodiment. Superiority is confirmed.

〔The invention's effect〕

As described above, according to the liquid crystal display element of the present invention, a multi-color display can be performed with one pixel by realizing the series combination of coloring by using a plurality of stacked liquid crystal cells and a color polarizing plate. A liquid crystal display element having a high response speed and a high response speed can be realized by employing a plate and employing a ferroelectric liquid crystal material.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing a schematic configuration of a first embodiment of the liquid crystal display device of the present invention, FIG. 2 is a sectional view of FIG. 1, and FIGS. FIG. 8 is a cross-sectional view showing a schematic configuration of a second embodiment of the present invention, and FIG. 9 is a schematic view showing a bending alignment process of a liquid crystal cell. 1 ... Liquid crystal display device, 2,3,4,81,83,85,87 ... Polarizing plate, 1
0A, 10B, 82, 84, 86 ... liquid crystal cell, 11A, 11B, 12A, 12B ... substrate, 13A, 13B ... liquid crystal layer, 14A, 14B, 15A, 15B ... electrodes.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-56-121076 (JP, A) JP-A-60-194426 (JP, A) JP-A-62-164024 (JP, A) JP-A-63-164 72784 (JP, A) JP-A-63-235916 (JP, A) JP-A-2-20 (JP, A) JP-A 64-33524 (JP, A) JP-A-61-140922 (JP, A) (58) Field surveyed (Int.Cl. ⁶ , DB name) G02F 1/141 G02F 1/1333 500 G02F 1/1337 510

Claims (1)

(57) [Claims] 1. A liquid crystal cell comprising: a plurality of liquid crystal cells; a polarizing plate disposed outside the laminate and between the liquid crystal cells;
A liquid crystal display element using a black polarizing plate for at least one of these polarizing plates and a color polarizing plate for at least one of the polarizing plates, wherein the liquid crystal cell is a pair of flexible plastic substrates facing each other. And an electrode provided on each of the opposing surfaces of these plastic substrates, and a ferroelectric liquid crystal material sandwiched between these electrodes, and subjected to an orientation treatment by bending deformation. The ferroelectric liquid crystal material contains at least one of a crosslinkable resin and an adhesive, and a ferroelectric polymer liquid crystal, and the entirety including the liquid crystal cell and the polarizing plate has flexibility. A liquid crystal display element comprising: