JP2002006294A - Liquid crystal element liquid crystal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal element with low power consumption, high brightness and high performance. SOLUTION: The liquid crystal element comprises a liquid crystal containing a rod-shaped liquid crystalline polymer and a rod-shaped low molecular weight liquid crystal composition for dual-frequency drive system used for a liquid crystal layer, in which the rod-shaped liquid crystalline polymer and the rod- shaped low molecular weight liquid crystal composition for the dual-frequency drive system are in a state with mutually separated phases, and modulates light by making the rod-shaped low molecular weight liquid crystal composition for the dual-frequency drive system switch.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal element and a liquid crystal device which can be used as a light valve used in a flat panel display, a paper display, a projection display, a printer, and the like.

[0002]

2. Description of the Related Art A CRT is known as a display which has been used most widely.
CRTs are widely used as moving image outputs for televisions and VTRs, or as monitors for personal computers and the like. However, due to the characteristics of the CRT, flicker and scanning fringes due to insufficient resolution lower the visibility of a still image,
Degradation of the phosphor due to burn-in may occur. Also,
The power consumption is considerably large, and improvement is required in terms of power saving. Since the CRT must have a large volume behind the screen due to its structure, the convenience of the information device having the CRT is limited, and it is not suitable for saving space in offices and homes.

As a solution to such a problem of the CRT, there is a liquid crystal display element. For example, "Applied Physics Letters" by M. Schadt and W. Helfrich (Applied Physics L)
etters) Vol. 18, No. 4 (February 15, 1971
Published on pages 127-128, twisted nematic
A device using a liquid crystal is known. In recent years, this type or VA (vertical alignment)
Mode, IPS (inplane switching)
2. Description of the Related Art A liquid crystal element called a TFT using a liquid crystal of a mode or the like has been developed and commercialized. In this type, since a transistor is formed for each pixel, there is no problem of crosstalk.
0-13 inch displays are being produced with good productivity.

However, these liquid crystals are usually used as a display by using a backlight and modulating light transmitted through the liquid crystal element. For this reason, strong light is required as a backlight, and most of the power consumption of the liquid crystal display is consumed by the backlight. Even if a lithium ion secondary battery is used, the continuous operation time of a mobile device or the like is at most several hours. is there. Also, if backlighting of more liquid crystal elements can be realized, more information devices,
The power consumption of office equipment will be reduced, and it will contribute to the suppression of global warming and the preservation of the global environment.

Under these circumstances, a low power consumption type reflection type liquid crystal element which does not use a backlight is being developed. However, at present, its characteristics are still required to be improved. In addition, products using a liquid crystal element as a projection type, so-called projector, have been marketed by various companies as large-screen displays. In this field, further improvements are required in terms of brightness and contrast. In response to such a demand, a scattering type liquid crystal element called a polymer dispersion type or a polymer network type liquid crystal has been proposed and studied, aiming at a high brightness liquid crystal element which does not require a polarizing plate (for example, 93 Euro
display 397). However, it is still desirable for these devices to have improved driving characteristics, scattering power and other characteristics.

In order to further reduce power consumption, a bistable PDLC (polymer-dispersed liquid crystal) using a dual-frequency drive liquid crystal has been proposed ("IEICE Technical Report", EID98).
-189, "OME" 98-143, P31 (1999)
-03)). In such a liquid crystal element as well, further improvement in electro-optical characteristics such as driving characteristics, luminance, and contrast is required.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above prior art, and it is an object of the present invention to provide a low power consumption, high luminance, high performance liquid crystal element, a light modulation element, and a display. It is an object to provide an element and a liquid crystal device.

[0008]

That is, the present invention comprises a liquid crystal layer using a liquid crystal containing a rod-like liquid crystalline polymer and a dual-frequency driven rod-like low-molecular liquid crystal composition. And a two-frequency driving rod-shaped low-molecular liquid crystal composition in a phase-separated state, and performing light modulation by switching the two-frequency driving rod-shaped low-molecular liquid crystal composition.

It is preferable that the dual frequency driven rod-shaped low molecular liquid crystal is switched between a homogeneous alignment and a homeotropic alignment. It is preferable that the liquid crystal is disposed between a pair of substrates and has an interface in contact with the liquid crystal, which has been subjected to a uniaxial alignment treatment. It is preferable that the liquid crystal element has no polarizing plate.

Preferably, light modulation is performed by modulating the relationship between the alignment axis of the rod-shaped liquid crystalline polymer and the alignment axis of the dual frequency driven rod-shaped low-molecular liquid crystal. Preferably, the rod-like liquid crystal is a nematic liquid crystal. It is preferable that an electrode and a liquid crystal be provided between a pair of substrates, and that a scattering state of light passing through the liquid crystal be modulated by an applied electric signal.

It is preferable that the liquid crystal device is a reflection type liquid crystal device in which the reflected light of the liquid crystal device is viewed as a display signal. It is preferable to provide a light absorbing plate or a light reflecting plate on the back surface of the liquid crystal layer. It is preferably a projection type liquid crystal element. Preferably, it has an active element.

Further, the present invention is a liquid crystal device using the above liquid crystal element.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION As a result of intensive studies, the present inventors have found that, in a liquid crystal containing a rod-shaped liquid crystalline polymer and a dual-frequency driven rod-shaped low-molecular liquid crystal composition, both liquid crystals are in a phase-separated state, By switching the rod-shaped low-molecular liquid crystal, it has been found that a liquid crystal element that performs light modulation can realize a liquid crystal element, a light modulation element, a display element, and a liquid crystal device with low power consumption, high luminance, and high performance. The invention has been completed.

Hereinafter, the present invention will be described in detail. In the present invention, in a liquid crystal containing a rod-shaped liquid crystalline polymer and a dual-frequency driven rod-shaped low-molecular liquid crystal composition, both liquid crystals are in a phase-separated state, and light is modulated by switching the rod-shaped low-molecular liquid crystal. This is the liquid crystal element.

FIG. 1 is a schematic diagram showing one embodiment of the cell configuration of the liquid crystal element of the present invention. 1 is a liquid crystal layer, 6 in the liquid crystal layer is a dual frequency driven rod-like low molecular weight liquid crystal part, and 7 is a polymer part containing repeating rod-like liquid crystal properties. In the liquid crystal layer 1, a polymer network is formed and is made of a rod-like liquid crystalline polymer. Separately, as a liquid crystal capable of responding to an electric field, there is a rod-shaped liquid crystal driven by two frequencies. The cell thickness of the liquid crystal layer 1 is preferably selected between 1 μm and 100 μm.

Reference numeral 2 denotes a substrate made of glass, plastic, or the like. Reference numeral 3 denotes an electrode, for which an ITO, a reflective electrode or the like is used. 4 is an orientation control layer. 5 is a spacer. In addition, short prevention layer, light absorption layer, reflection layer,
It is also possible to provide a color filter layer. Also,
The upper and lower substrates may be asymmetric. The liquid crystal element of the present invention can have the above structure, but is not limited to them.

The polymer network type or polymer dispersion type liquid crystal of the liquid crystal layer 1 is prepared, for example, by mixing a polymer monomer having at least a rod-like liquid crystal monomer and a rod-like liquid crystal, injecting the mixture into a liquid crystal cell, and irradiating ultraviolet rays. By doing so, it is possible to create. Preferably, a nematic liquid crystal state is formed between the substrates that have been subjected to the uniaxial alignment treatment, and photopolymerization is performed in this state, so that the polymer matrix and the two-frequency driven low-molecular liquid crystal are uniaxially aligned.

The rod-shaped liquid crystal used in the present invention is a liquid crystal such as a nematic liquid crystal, a cholesteric liquid crystal, a smectic liquid crystal, a chiral smectic liquid crystal, and the liquid crystal contains at least one compound. Preferably, a mixture of a plurality of rod-shaped liquid crystal compounds is used in order to widen the liquid crystal temperature range and optimize various physical properties.

The two-frequency driven liquid crystal is a liquid crystal having a different dielectric anisotropy sign depending on the frequency of an applied electric field. For example, it refers to a liquid crystal in which liquid crystal molecules are aligned in parallel with the direction of an electric field when a low-frequency electric field is applied, and are oriented perpendicular to the direction of an electric field when a high-frequency electric field is applied. Specific compounds and compositions for the dual-frequency driven liquid crystal include, for example, 2,3-
Dicyano-4-pentyloxyphenyl-4- (tra
ns-4-ethylcyclohexyl) benzoate, 2,
3-dicyano-4-pentyloxyphenyl-tran
s-4-propyl-1-cyclohexanecarboxylate, 2,3-dicyano-4-ethoxyphenyl-4-
(Trans-4-pentylcyclohexyl) benzoate, 2,3-dicyano-4-ethoxyphenyl-4-
(Trans-4-butylcyclohexyl) benzoate, 2,3-dicyano-4-butoxyphenyl-4-
Low-molecular liquid crystals such as (trans-4-butylcyclohexyl) benzoate can be used alone or as a mixture of two or more. Further, they may be used by mixing with other liquid crystal compounds. Of course, a dye, an antioxidant and the like may be added and used.

The dual frequency driven rod-like low molecular weight liquid crystal composition of the present invention contains at least one or more of the above-mentioned dual frequency driven rodlike low molecular weight liquid crystal. Or a mixture containing two or more kinds, and may contain a liquid crystal compound, a dye, an antioxidant and the like other than these.

As a rod-shaped polymer liquid crystal forming a polymer matrix, a method of obtaining a liquid crystal monomer by photopolymerization is preferably used. Specific examples of the liquid crystal monomer used include a liquid crystal compound having a polymerizable group such as an acryl group, a methacryl group, and an epoxy group. More specific examples include the following.

[0022]

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[0023]

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[0024]

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In the above formulas a) to w), p is 1 to 20, q
Represents 1 to 20.

[0026]

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[0030]

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[0036]

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[0039]

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[0040]

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Using the liquid crystal material as described above,
It is possible to form the liquid crystal used in the present invention.
In the present invention, a rod-shaped liquid crystalline polymer is used. As described above, the dual-frequency driven rod-shaped low-molecular liquid crystal and the rod-shaped liquid crystalline high-molecular monomer can be obtained by polymerization in a cell by external irradiation such as ultraviolet rays. In this process, a rod-like liquid crystal layer is formed by phase separation. At this time, a photopolymerization initiator is often used to promote photopolymerization. In order to obtain more preferable scattering, controlling the phase before or during the polymerization to control the droplet diameter can be performed in the same manner as in a normal polymer dispersion type or polymer network type liquid crystal.

The liquid crystal containing the rod-shaped liquid crystalline polymer of the present invention and the dual-frequency driven rod-shaped low-molecular liquid crystal composition is obtained by directly mixing the rod-shaped liquid crystalline polymer with the dual-frequency driven rod-shaped low-molecular liquid crystal. Any desired material can be used.

Examples of the rod-like liquid crystalline polymer liquid crystal include compounds described in JP-A-7-82183, and specific examples are given below.

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[0046]

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[0054]

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[0055]

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[0056]

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(In the following formulas (1) to (13), 15> n ≧
It is one. )

[0058]

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[0059]

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(In the following formulas (14) to (17), q = 1 to
18, q ₁ = 1 to 18, and q ₂ = 1 to 18. )

[0061]

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(In the following formulas (18) to (62), * represents an asymmetric carbon center.)

[0063]

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[0072]

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[0073]

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[0074]

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[0075]

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(Where n is an integer from 2 to 12)

Regarding the mixing ratio between the rod-shaped liquid crystalline polymer and the dual-frequency driven rod-shaped low-molecular liquid crystal composition, 1 wt% of the rod-shaped liquid crystalline polymer is required from the viewpoint of the scattering ability and the necessity of showing each physical property. Or more and 99 wt% or less, preferably 2 wt% or more and 90 wt% or less, more preferably 5 wt% or more and 70 wt% or less. On the other hand, the component ratio of the dual frequency driven rod-shaped low-molecular liquid crystal composition was similarly 1 wt%.
Or more and 99 wt% or less, preferably 10 wt% or more and 98 wt% or less, more preferably 30 wt% or more and 95 wt% or less.
wt% or less. In the mixture of the present invention, if necessary, an antioxidant, a radical scavenger, a photoreaction inhibitor,
Additives such as a polymerization inhibitor and a dye may be contained.

In the present invention, in order to obtain a more preferable orientation state, it is also possible to perform a heat treatment after the above-described production steps. By applying the heat treatment, the rod-shaped liquid crystalline polymer and / or the dual-frequency driven rod-shaped low-molecular liquid crystal composition may achieve a self-organization and create a more preferable alignment state.

Hitherto, studies have been made to form a so-called polymer-dispersed self-scattering liquid crystal using a two-frequency driven liquid crystal. One is to develop bistability and to reduce the drive power consumption by using its memory properties. However, when performing matrix driving, it is still required to improve driving characteristics. In particular, there is a strong demand for controlling threshold characteristics which are important for performing matrix driving. Further, improvement in optical characteristics such as luminance and contrast is also strongly required.

Under such circumstances, the present invention provides a liquid crystal element having a very improved optical characteristic such as luminance and contrast and excellent driving characteristics by using a two-frequency driven rod-shaped low-molecular liquid crystal composition. is there.

In the liquid crystal containing the rod-shaped liquid crystalline polymer of the present invention and the dual-frequency driven rod-shaped low-molecular liquid crystal composition, both liquid crystals are in a phase-separated state. The reason why the luminance and the contrast of the liquid crystal element performing the light modulation are excellent will be described with reference to FIGS.

FIG. 2 shows a switching model of the liquid crystal element of the present invention using a refractive index ellipsoid. It is well known that refractive index matching and mismatching are factors that largely control the light scattering state. As shown in FIG. 2, the on-off state is a state in which the refractive index of the liquid crystal driven by dual frequency and the refractive index of the rod-shaped polymer liquid crystal as a matrix are matched and mismatched. The state on the left where the refractive index matches is normally the non-scattering state, and the state on the right where the refractive index mismatch is the scattering state. In FIG. 3, the matrix polymer was compared with a PDLC using a normal polymer.

In the ordinary PDLC, the scattering state of the liquid crystal uses the state of random alignment, and the refractive index mismatch with the matrix polymer is not sufficient. The ratios are mismatched sufficiently, and large light scattering is obtained. In comparison with the off state, in the ordinary PDLC, the refractive index in the Z direction is largely mismatched, and although the contribution is small, the light is scattered with respect to light from an oblique direction.
In the present invention, the refractive indexes are well matched in any direction. In the case of the reflective liquid crystal in which the off state is set to the black state, it is apparent that this greatly contributes to the improvement of the contrast.

Also, regarding the threshold characteristics strongly required for performing the matrix driving, since a rod-shaped polymer liquid crystal having similar characteristics is used for the matrix, a normal dual frequency driving liquid crystal was used. Compared with the normal PDLC, it has a stronger anchoring effect in the alignment state on the left side of FIG.

As described above, the liquid crystal element of the present invention is preferably subjected to a uniaxial alignment treatment in order to exhibit a good scattering state. As a method of forming the uniaxial orientation control layer, for example, a solution coating or vapor deposition or sputtering on a substrate is performed by using silicon monoxide, silicon dioxide, aluminum oxide, zirconia, magnesium fluoride, cerium oxide, cerium fluoride, silicon nitride. , Silicon carbide, inorganic substances such as boron nitride, polyvinyl alcohol, polyimide, polyimide amide, polyester, polyamide, polyester imide, polyparaxylene, polycarbonate, polyvinyl acetal, polyvinyl chloride, polystyrene, polysiloxane, cellulose resin, melamine resin, urea It is obtained by forming a film using an organic substance such as a resin or an acrylic resin and then rubbing the surface with a fibrous material such as velvet, cloth or paper. Also, an oblique deposition method of depositing an oxide or a nitride of SiO or the like from the oblique direction of the substrate may be used.

In particular, it is preferable to use a polyimide rubbing film as the uniaxially oriented layer in order to obtain better uniaxial orientation. Usually, polyimide is obtained by coating a film in the form of polyamic acid and baking it. Polyamic acid is excellent in productivity because it is easily soluble in a solvent. Recently, polyimides soluble in solvents have also been produced, and from the viewpoint of such technological advances, polyimide is preferably used because it can obtain better uniaxial orientation and has high productivity. Examples of the specific repeating unit structure of polyimide that can be used include the following, but of course, these do not limit the present invention.

[0087]

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Wherein A: a tetravalent group having an aromatic ring, an aromatic polycyclic ring, a heterocyclic ring, an aliphatic ring or a condensed polycyclic structure; B: an aliphatic group containing an alicyclic group; or

[0089]

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(Ph represents a phenyl group) D;

[0091]

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(R ₁ and R ₂ are each independently H or an optionally substituted alkyl group) a = b: 0 or 1 c = d: 0 when a = b = 0, a = b When = 1, 0 or 1 e: 0 or 1 x, y: each independently an integer of 1 or more, provided that x + y + e is 2 or more and 10 or less. ]

The two substrates face each other via a spacer. Such a spacer determines the distance (cell gap) between the substrates, and silica beads, partition spacers, resin spacer beads, and the like are used. The optimum range and the upper limit of the cell gap determined here are different depending on the liquid crystal material.
It is preferable to set it in the range of m.

In general, the problem of drive hysteresis is still serious for polymer dispersed liquid crystal PDLC.
PDLC using polymer liquid crystal matrix as conventional technology
Has been proposed in SID98DIGEST 758. However, since the liquid crystal element of the present invention uses a dual-frequency drive liquid crystal, electric field control can be performed for both on and off switching. It is excellent because it can be performed and the hysteresis can be greatly improved. In addition, since bistability can be imparted as described above, it is possible to use a memory state to significantly reduce driving power consumption and to provide a reflection-type liquid crystal with extremely low power consumption.

Also, a lecture of the 22nd Liquid Crystal Symposium (Preliminary proceedings of the 22nd Liquid Crystal Symposium); In 3D10, there is no phase separation using a polymer liquid crystal or a scattering type in which phase separation is extremely insufficient. Although a liquid crystal element has been proposed, there is still a large practical problem in that the time required for switching is very long or unclear, or the method of resetting to the initial state is heat treatment.

For the liquid crystal element prepared as described above, the transmitted light or the reflected light can be modulated by controlling the electric field and changing the alignment state of the rod-shaped liquid crystal. Is treated as a display signal, it becomes a display element. In addition, analog gray scale expression can be easily performed by using the intermediate voltage signal.

A light absorbing plate, and in some cases, a reflecting plate or a scattering plate (for example, an I.D.
DRC, 1994, p. 183. ) Can provide a reflective liquid crystal display element. FIG. 4 shows, as an example of the structure, a liquid crystal element in which a light absorbing plate 8 is provided between a lower electrode and a substrate. For example, by using an active matrix element to be described later,
A liquid crystal device with high definition, high speed, and excellent driving characteristics can be realized.

Since strong scattering is obtained by using the liquid crystal element of the present invention, a high-brightness reflective liquid crystal element having high light reflectance can be realized. This reflection type liquid crystal element can be used as a direct-view type liquid crystal display element using external light or an auxiliary light source. In addition, strong light enters from the front,
The present invention can also be used as a so-called projection type liquid crystal element in which light modulated and reflected by a liquid crystal element is controlled on an optical path and then projected on a screen.

On the other hand, a projection type liquid crystal element, that is, a projection type liquid crystal element, can be used as a transmission type liquid crystal element instead of a reflection type liquid crystal element. FIG. 5 shows an example of a typical transmission type projection liquid crystal element. 3
A color image can be projected on a projection screen by using a liquid crystal element having a matrix pattern such as an active matrix element described later for the liquid crystal elements corresponding to the three primary colors 03, 303 ′, and 303 ″.
The liquid crystal element of the present invention performs black display in a scattering state, and a higher contrast can be realized in the liquid crystal element of the present invention in which stronger scattering can be obtained.

Further, an active element which is one mode of the liquid crystal element of the present invention will be described below. For example, the active matrix element shown in FIG. 6 is exemplified by using the configuration described above as one pixel. A pair of transparent substrates (for example, glass substrates) 41 and 42
Among them, on the lower substrate 41, a transparent pixel electrode 43 and an active element 44 connected to the pixel electrode 43 are formed in a matrix. The active element 44 is, for example, TF
It is composed of a thin film transistor called T. As the transistor, a semiconductor such as an amorphous silicon base, a polysilicon type, a μ crystal base, or a single crystal silicon can be used. In this example, reference numeral 44 denotes a TFT. 44 includes a gate electrode formed on the substrate 41, a gate insulating film covering the gate electrode, a semiconductor layer formed on the gate insulating film, and a source electrode and a drain electrode formed on the semiconductor layer. .

Further, on the lower substrate 41, gate lines (scan lines) 45 are arranged between rows of the pixel electrodes 43 as shown in FIG. 7, and information signal lines 46 are arranged between the columns of the pixel electrodes 43. The gate electrode of each TFT 44 is connected to a corresponding gate line 45, and the drain electrode is connected to a corresponding information signal line 46. Gate line 4
5 is connected to a row driver via an end 45a, and the information signal line 46 is connected to a column driver via an end 46a. The row driver scans the gate line 45 by applying a gate signal. The column driver applies a signal corresponding to the display data. The gate line 45 is covered with the gate insulating film of the TFT 44 except for the end 45a, and the information signal line 46 is formed on the gate insulating film. The pixel electrode 43 is formed on the gate insulating film, and has one end connected to the source electrode of the TFT 44. Further, the counter electrode 47 forms an electrode connected to the TFT, and a reference voltage is applied. The transmittance or the reflectance changes in accordance with the information signal voltage applied to the electrode on the TFT side, so that gradation expression can be performed. In addition, a capacitor serving as an auxiliary capacitance is often arranged for each pixel.

In the active element described above,
When the gate is on, charge is injected into the liquid crystal cell as a pixel, the gate is turned off in a short time, and information is written to the pixel on the next scan line.

The liquid crystal element of the present invention can be used as a light valve of a printer or the like. The liquid crystal element of the present invention can constitute a liquid crystal device having various functions. For example, mobile, PDA, desktop PC,
Examples include a laptop PC, a video camera, a digital camera, a document viewer, a printer, a copying machine, and the like.

In the liquid crystal device of the present invention, since the liquid crystal element as the medium has good switching characteristics as described above,
It exhibits excellent driving characteristics and reliability, and can realize a high-definition, high-speed, large-area display image.

[0105]

Next, the present invention will be described more specifically with reference to examples and comparative examples. Note that the present invention is not limited to these examples.

Example 1 <Polymerizable rod-like liquid crystalline compound A used>

[0107]

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<Used low-molecular rod-shaped liquid crystal B> Rod-shaped liquid crystal B
As P-type fluorinated nematic liquid crystal DF manufactured by Chisso
01XX was used.

Using these, A and B were mixed at the following weight mixing ratio to prepare a mixture of a polymerizable discotic liquid crystalline compound and a rod-like liquid crystal. Mixture A / B = 30/7
0. This mixture was dissolved in the isotropic state. Also, 50 ° C
Showed nematic liquid crystallinity.

<Creation of Cell> Thickness l. 1. Polyamic acid as a polyimide precursor having a repeating unit represented by the following structural formula with respect to a 1 mm glass substrate with an ITO electrode (using two sheets). The 1 wt% solution was spin-coated at 500 rpm for 5 seconds for the first time and at 1500 rpm for 30 seconds for the second time.

[0111]

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After that, pre-drying was carried out at 80 ° C. for 5 minutes, followed by baking at 220 ° C. for 1 hour. Rubbing treatment with a nylon cloth was performed on the alignment films on both substrates as a uniaxial alignment treatment.

An IPA solution in which resin beads having an average particle diameter of 10 μm were dispersed at 0.01% by weight on the surface of one of the substrates was used.
Spin coating was performed at 500 rpm for 10 seconds, and bead spacers having a dispersion density of about 100 / mm ² were sprayed.
A thermosetting liquid adhesive was applied to the substrate by a printing method.

The obtained two substrates were bonded to each other with the rubbing axis aligned and heated and cured in an oven at 150 ° C. for 90 minutes to obtain a cell.

In the mixture, 2,6-dital butyl-
200 ppm of 4-methylphenol was added, and 2 parts of Irgacure 184, a photopolymerization initiator manufactured by Ciba Geigy, were added.
After the addition of wt%, normal pressure injection was performed at 100 ° C. into the cell. It was observed under a polarizing microscope that the composition was uniaxially oriented in the rubbing direction at 50 ° C. About 1 in this state
Exposure was performed for 10 minutes with ultraviolet light of ² mW / cm ² and a central wavelength of 365 nm to form a liquid crystal cell.

According to observation under a polarizing microscope in a hot stage manufactured by Mettler Co., the low-molecular rod-shaped liquid crystal DF01XX has a temperature higher than the temperature at which the low-molecular rod-shaped liquid crystal DF01XX becomes an isotropic phase.
The texture of the polymer liquid crystal polymerized at 20 ° C. was observed, and it was uniaxially oriented. From this, it was confirmed that the polymerizable rod-like liquid crystalline compound was polymerized to be a polymer compound. It was observed under a polarizing microscope that the low-molecular rod-shaped liquid crystal was well uniaxially oriented.

Comparative Example 1 41% by weight of 2-hydroxyethyl methacrylate, 17% by weight of a crosslinkable monomer R-167 manufactured by Nippon Kayaku Co., Ltd., a photopolymerization initiator Darocure 117 manufactured by Ciba Geigy
3 was mixed with 61 parts by weight of a polymer precursor consisting of 3% by weight and 39 parts by weight of the low-molecular rod-like liquid crystal DF01XX was injected into the following cell, and photopolymerized in the same manner as in Example 1.
PDLC was made.

A cell was prepared in the same manner as in Example 1 except that the upper and lower substrates were changed to glass substrates with ITO transparent electrodes, and no alignment film was used. A black light-absorbing plate was placed on the back of the cell prepared above, and the reflected light intensity was measured with an automatic change photometer GP-200 manufactured by Murakami Color Research Laboratory. The light intensity in the direction of the emission angle of 0 degree at the incident angle of 30 degrees was compared between the cell of Comparative Example 1 and the cell having the composition of Example 1.

A state in which an electric field of 100 V and 60 Hz was applied was a scattering state in Example 1, a non-scattering state in Comparative Example 1, and a non-scattering state in Example 1 when no voltage was applied.
In the case of Comparative Example 1, when compared in the scattering state, the cell of Example 1 had a reflection intensity 1.9 times that of the cell of Comparative Example 1 in the scattering state. Further, when the contrast between the non-scattering state and the scattering state was compared, the cell of Example 1 was 1
/4.8, whereas the cell of Comparative Example 1 was 1/1.
It was 8. Next, in order to compare the threshold characteristics, when the voltage value at which the reflection intensity in the no-voltage applied state changes by 3% was compared, the cell of Example 1 was 11.0 V,
Comparative Example 1 was at 1.5 V and had almost no threshold value.

Example 2 A mixture was prepared in which the composition of the liquid crystal material of Example 1 was A / B = 20/80, and a cell was prepared in the same manner as the mixture of Example 1. When this cell and Comparative Example 1 were compared in the same manner as in Example 1, the cell of this example had a reflection intensity 1.8 times that of Comparative Example 1 and a contrast of 1 / 4.9. Further, the voltage value at which the reflection intensity with no voltage applied changes by 3% was 9.8 V, which was a desirable threshold value characteristic.

Embodiment 3 The cells prepared in Embodiments 1 and 2 are replaced with the liquid crystal elements 303, 303 ', and 30 in the liquid crystal element portion of the projection optical system shown in FIG.
3 "and projected on a screen. 50 V, 60
The luminance on the screen changed with good contrast between the state where the electric field of Hz was applied and the state where the electric field was not applied.

Embodiment 4 Using a single crystal silicon transistor (on resistance 50 Ω), the liquid crystal test cell (area 0.9 cm ² ) used in Embodiment 1 and a ² nF ceramic capacitor as described in FIG. Then, an active element was created. A gate signal having a selection period of 30 .mu.S is applied thereto, and 30 V, -30 V, 30 V, -30 V are supplied from the information signal line.
Waveforms were given in the order of V, 0V, 0V, 0V, 0V. When a voltage signal was applied to the liquid crystal cell so that the frame frequency became 10 Hz, good contrast was visually observed.

Fifth Embodiment In the active device of the fourth embodiment, a new gate signal is applied for 0.1 second between the fourth and fifth signals.
The fifth case (0 V) using a photomultiplier under a polarizing microscope was performed when a signal of 100 kHz was applied to the device and when the cell of Comparative Example 2 described below was driven in the same manner as in Example 4.
And the luminance under the sixth (0 V) signal was measured and compared.

Comparative Example 2 Hexylene diacrylate and nematic liquid crystal KN5027 manufactured by Chisso were used and their weight ratio was 50/50.
The mixture was adjusted with. This was injected into the cell of Comparative Example 1 described above, and exposed to UV light in the same manner as described above, to produce a polymer dispersed liquid crystal element.

In the case of the fifth embodiment, no difference in luminance was recognized, but in the case of comparative example 2, the luminance of the sixth pixel was twice or more the luminance of the fifth pixel, and large hysteresis was present. .

[0126]

As described above, according to the liquid crystal device of the present invention, the brightness and the contrast are higher than the conventional polymer dispersion type or polymer network type liquid crystal device which is bright and does not require a polarizing plate. Thus, a practical and high-performance liquid crystal element, light modulation element, display element, and liquid crystal device having low power consumption and excellent driving characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of a cell configuration of a liquid crystal element of the present invention.

FIG. 2 is a diagram showing a switching model of a liquid crystal element of the present invention using an index ellipsoid.

FIG. 3 shows a liquid crystal device of the present invention and P using a normal polymer.
It is the figure shown in comparison with DLC.

FIG. 4 is a schematic view showing another example of the cell configuration of the liquid crystal element of the present invention.

FIG. 5 is a schematic view showing an example of a typical transmission type projection liquid crystal element.

FIG. 6 is a schematic diagram illustrating an example of an active matrix element.

FIG. 7 is a schematic diagram illustrating an example of an active matrix element.

FIG. 8 is an explanatory diagram of an active element used in Example 4 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal layer 2 Substrate 3 Electrode 4 Alignment control layer 5 Spacer 6 Dual frequency driven rod-shaped liquid crystal part 7 Polymer part containing rod-shaped liquid crystal repetition 8 Light absorption plate 31 Row driver 32 Column driver 41 Lower transparent substrate 42 Upper side Transparent substrate 43 Pixel electrode 44 Active element (TFT) 45 Gate line (scan line) 46 Data line (gradation signal line) 47 Counter electrode 301 Light source unit 302, 302 ', 302 "Dichroic mirror 303, 303', 303" Liquid crystal Element 304, 304 ', 304 "Schlieren optical system 305 Dichroic prism 306 Projection lens 307 Liquid crystal element driving device 61 Liquid crystal cell 62 Capacitor 63 Transistor: silicon single crystal transistor 64 Gate signal 65 Information signal

Continued on front page F-term (reference) 2H089 HA04 JA04 KA19 QA16 RA09 TA04 TA07 TA09 TA13 TA17 UA05 2H093 NA16 NA17 ND04 ND08 ND39 NE04 NE06 NF11 NG02

Claims (12)

[Claims] 1. A liquid crystal layer using a liquid crystal containing a rod-shaped liquid crystalline polymer and a dual-frequency driven rod-shaped low-molecular liquid crystal composition,
A liquid crystal, wherein the rod-shaped liquid crystalline polymer and the two-frequency driven rod-shaped low-molecular liquid crystal composition are in a phase-separated state, and light modulation is performed by switching the two-frequency driven rod-shaped low-molecular liquid crystal composition element. 2. The liquid crystal device according to claim 1, wherein the dual frequency driven rod-like low molecular liquid crystal is switched between a homogeneous alignment and a homeotropic alignment. 3. The liquid crystal device according to claim 1, wherein the liquid crystal is disposed between a pair of substrates and has an interface in contact with the liquid crystal, which has been subjected to a uniaxial alignment treatment. 4. The liquid crystal device according to claim 1, which does not have a polarizing plate. 5. The liquid crystal according to claim 1, wherein light modulation is performed by modulating the relationship between the alignment axis of the rod-shaped liquid crystalline polymer and the alignment axis of the dual-frequency driven rod-shaped low-molecular liquid crystal. element. 6. The liquid crystal device according to claim 1, wherein the rod-shaped liquid crystal is a nematic liquid crystal. 7. The liquid crystal element according to claim 1, further comprising an electrode and a liquid crystal between the pair of substrates, and modulating a scattering state of light passing through the liquid crystal by an applied electric signal. . 8. The liquid crystal element according to claim 1, wherein the liquid crystal element is a reflection type liquid crystal element in which reflected light of the liquid crystal element is viewed as a display signal. 9. The liquid crystal device according to claim 8, wherein a light absorbing plate or a light reflecting plate is provided on a back surface of the liquid crystal layer. 10. A projection-type liquid crystal element.
The liquid crystal element according to any one of the above items. 11. The liquid crystal device according to claim 1, further comprising an active device. 12. A liquid crystal device using the liquid crystal element according to claim 1.