JPH0959628A - Liquid crystal element and liquid crystal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal element comprising base plates, electrodes, controlled alignment layers each having a specified thickness and a specified liquid crystal and using a high-reliability chiral smectic liquid crystal. SOLUTION: This liquid crystal element comprises upper and lower base plates, electrodes, controlled alignment layers each having a thickness of 200Å and a chiral smectic liquid crystal composition, the liquid crystal composition being a chiral smectic liquid crystal composition containing a perfluorocarbon compound containing 70wt.% or above group of smectic or latently smectic fluorine-containing liquid crystal compounds each of which has a fluorocarbon terminal part and a hydrocarbon terminal part which are bonded through a central nucleus and in which 30wt.% or above, based on the liquid crystal, compounds having a fluorocarbon terminal chain interrupted by an etheric oxygen and comprising at least one 2-30C hydrocarbon chain in which methylene groups may be substituted by Y, YCO or the like (wherein Y is O or S).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal element used for a light valve used in a flat panel display, a projection display, a printer and the like, and a liquid crystal device using the same.

[0002]

2. Description of the Related Art A CRT is known as the most widely used display. CRT
Is widely used as a moving image output for televisions and VTRs, or as a monitor for personal computers. However,
Due to the characteristics of the CRT, the visibility of a still image may be reduced due to flicker or scanning fringes due to insufficient resolution, or the phosphor may be deteriorated due to burn-in. In addition, recently, it has been found that the electromagnetic waves generated by the CRT adversely affect the human body, which may impair the health of the VDT worker.
Further, because of the large volume behind the screen in terms of structure, space saving in offices and homes may be hindered, and it may not be possible to fulfill the responsibility as a display in an advanced information society.

As a solution to such a disadvantage of the CRT, there is a liquid crystal display element. For example, M. Shut (M.
Schadt) and W. Helfrich (W. He)
Lfrich) "Applied Physics Letters"
s ") Volume 18, Issue 4 (issued February 15, 1971)
Twisted shown on pages 127-128
A liquid crystal device using a nematic (twisted nematic) liquid crystal is known. One is a simple matrix type liquid crystal element, which has a cost advantage. This liquid crystal element has a problem that crosstalk occurs in time-division driving using a matrix electrode structure with a high pixel density, so that the number of pixels is limited. Moreover, since the response speed is as slow as several tens of milliseconds or more, its use as a display is limited. In recent years, a liquid crystal element called TFT has been developed for such a simple matrix type. Since this type creates a transistor in each pixel, the problems of crosstalk and response speed are solved, but it is industrially very difficult to create a liquid crystal element without a defective pixel as the area increases. Difficult and, if possible, at great cost.

In order to improve the drawbacks of the conventional liquid crystal device, the use of a bistable liquid crystal device is clarified by Clark and Lagerw.
all) proposed. (JP-A-56-107
216, U.S. Pat. No. 4,367,924) As the liquid crystal having the bistability, a ferroelectric liquid crystal having a chiral smectic C phase or a chiral smectic H phase is generally used. Since the ferroelectric liquid crystal performs inversion switching by spontaneous polarization, the ferroelectric liquid crystal has a very fast response speed and can exhibit a bistable state with memory properties. Further, since the viewing angle characteristics are also excellent, it is considered that they are suitable as a high-speed, high-definition, large-area display element or a light valve. Recently, Chandani and Takezoe have also proposed a chiral smectic antiferroelectric liquid crystal device having three stable states (Japanese Journal of Applied Physics).
of Applied Physics) 27, 198
8 years L729 page).

In such a chiral smectic liquid crystal element, as described in, for example, "Structure and Physical Properties of Ferroelectric Liquid Crystal" (Corona Publishing Co., Atsuo Fukuda, Hideo Takezoe, 1990), a zigzag alignment defect is formed. However, there is a problem that the contrast is significantly reduced. This defect is caused by the fact that the layered structure of the chiral smectic liquid crystal carried between the upper and lower substrates forms two types of chevron-like structures. Recently, there has been a movement to eliminate the chevron structure that causes the low contrast, and to reveal a layered structure called a bookshelf (hereinafter referred to as a bookshelf) or a structure close thereto to realize high contrast (for example, "Next-generation liquid crystal displays and liquid crystal materials" CMC Corporation, edited by Atsuo Fukuda, 1992). One method is to use a naphthalene-based liquid crystal material. In this case, the tilt angle is 10
22. It is about the degree and the ideal maximum transmittance is obtained.
There is a problem that the transmittance is very small as compared with 5 degrees and the transmittance is low, and there is also a problem that the bookshelf structure does not reversibly appear with respect to temperature. Another typical example is a method of inducing a bookshelf structure by applying a high electric field from the outside to a liquid crystal element having a chevron structure, but this method also has instability against external stimuli such as temperature. It's a problem. These bookshelf types have just been discovered, and there are various other problems for practical use.

Furthermore, a liquid crystal compound having a perfluoroether side chain as a liquid crystal having a structure of a bookshelf or a structure close to the bookshelf (US Pat. No. 5,262,082, International Patent Application WO 93/22396, 1993 4th Ferroelectric Liquid Crystal International Conference) P-46, Marc D. Radcliffe
Are disclosed. This liquid crystal can exhibit a bookshelf or a structure having a small layer inclination angle close to it without using an external field such as an electric field, and is suitable for a high-speed, high-definition, large-area liquid crystal element and a display device. However, further improvements are required in terms of speed, orientation, contrast, driving stability, etc. of liquid crystal elements. Moreover, in addition to improving each characteristic, a method and invention for improving a plurality of characteristics are required for higher performance.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and is intended to realize a highly reliable chiral smectic liquid crystal element, and to use the element. The present invention intends to provide a display device with high brightness and high contrast.

[0008]

As a result of intensive studies, the inventors of the present invention have at least electrodes and alignment control layers on the upper and lower substrates, and at least one of the alignment control layers has a film thickness of 200.
Å or less, and the liquid crystal has a fluorocarbon end portion and a hydrocarbon end portion, both end portions are bound by a central nucleus, a fluorine-containing liquid crystal compound group having a smectic phase or potentially a smectic phase Of 70% by weight or more and 30% by weight of the above-mentioned fluorine-containing liquid crystal compound containing at least one ether oxygen in the chain in the fluorocarbon end chain.
A liquid crystal device characterized by containing at least one kind of a specific perfluoro compound, which has a structure of a bookshelf or a layer having a small layer tilt angle, and has high speed, high contrast, large area, high We have found that it enables the realization of high-definition, high-brightness chiral smectic liquid crystal devices, and has high reliability, especially no initial asymmetry problem.

In the present invention, the specific perfluoro compound means a compound having the following structure.

A perfluoro compound having an optionally branched carbon chain having 2 to 30 carbon atoms and having at least one perfluoro carbon, wherein one or more methylene groups in the carbon chain are Y-, -YCO-, -C
OY-, -CO-, -OCOO-, -CH = CH-,-
It may be replaced by C≡C- (Y is O or S), and -OH or -NRR 'in any of the carbon chains.
(R and R ′ are the same or different hydrogen, or an alkyl group having 1 to 5 carbon atoms) or —COOH may be substituted, and α (α is a single or plural —OH. , -NH _2, -CN, -F phenyl group where optionally substituted) is optionally substituted compound.

In the present invention, the ether oxygen in the chain refers to oxygen forming the main chain in the perfluoroether chain.

[0012]

1 shows an example of a liquid crystal device of the present invention. Reference numeral 1 is a liquid crystal layer composed of a chiral smectic liquid crystal composition. Usually, the layer thickness is preferably 5 μm or less in order to exhibit bistability. 2 is a substrate, glass,
Plastic or the like is used. 3 is a transparent electrode such as ITO. Reference numeral 4 denotes an orientation control layer, which requires a uniaxial orientation control layer on at least one substrate. As a formation method,
For example, an inorganic substance such as silicon monoxide, silicon dioxide, aluminum oxide, zirconia, magnesium fluoride, cerium oxide, cerium fluoride, silicon nitride, silicon carbide, boron nitride, etc. by solution coating or vapor deposition or sputtering on a substrate. Or using organic substances such as polyvinyl alcohol, polyimide, polyimide amide, polyester, polyamide, polyester imide, polyparaxylene, polycarbonate, polyvinyl acetal, polyvinyl chloride, polystyrene, polysiloxane, cellulose resin, melamine resin, urea resin, and acrylic resin. After forming a film, it can be obtained by rubbing the surface with a fibrous material such as velvet, cloth or paper. Further, an oblique vapor deposition method in which an oxide such as SiO or a nitride is vapor-deposited from the oblique direction of the substrate can also be used.

The structure of the liquid crystal device of the present invention is not limited as long as at least one of the orientation control layers has a film thickness of 200 Å or less and the specific chiral smectic liquid crystal composition is used to impart a predetermined function. .

In addition to the above-mentioned orientation control layer, an insulating layer as another short-circuit preventing layer for the upper and lower substrates, another organic material layer, or an inorganic material layer may be formed. Reference numeral 5 is a sealing material that bonds the substrates together. In addition, a gap control spacer (not shown) such as silica beads is provided between the substrates.
6 is a lead wire, 7 is a signal power source, 8 is a polarizing plate, and 9 is a light source. Switching is performed in response to a switching signal from 7 and functions as a light valve for a display element or the like.
Further, if the three transparent electrodes are arranged in a matrix in the upper and lower cross, pattern display and pattern exposure become possible, and they are used as, for example, displays for personal computers, word processors, etc., and light valves for printers.

In the present invention, a fluorocarbon terminal portion and a hydrocarbon terminal portion used as liquid crystal components in the present invention are contained, and at least one ether oxygen in the chain is contained in the fluorocarbon terminal chain, and both terminal portions are bound by a central nucleus. The fluorine-containing liquid crystal compound having a smectic mesophase or a latent smectic mesophase is disclosed in US Pat. No. 5,262,082 and International Patent Application WO
93/22396, 1993 4th International Conference on Ferroelectric Liquid Crystals P-46 (Marc D. Radcliffe et al.), Which is a perfluoroether liquid crystal compound.

As used herein, a compound having a latent smectic mesophase does not show a smectic mesophase by itself, but in a mixture with a compound having a smectic mesophase or another compound having a latent smectic mesophase, A compound that develops a smectic mesophase under appropriate conditions.

The above perfluoroether liquid crystal compound can be represented by the following general formula I-1 and is preferably used from the viewpoint of having good liquid crystallinity.

[General Formula I-1]

[0019]

Embedded image And a, b and c are each independently 0 or 1 to 3
Represents the integer. However, a + b + c is at least 2.

A and B may be oriented in either direction,
Independently, -COO-, -COS-, -COSe-,
_{-COTe -, - (CH 2 CH} 2) k - (k represents an integer of from 1 4), - C≡C -, - CH = CH -, - CH =
_{N -, - CH 2 -O -} , - CO -, - O-, a single bond.

X, Y and Z are independently -H and -C.
l, -F, -Br, -I, -OH, -OCH 3, -C
H _3, represents -CF _3, -OCF _3, -CN, and -NO _2.
l, m, and n each independently represent an integer of 0 to 4.

[0022] D is _{-COO-C r H 2r -,} - O-C r H 2r
_{-, - O (C s H} 2s O) t -C r 'H 2r' -, - C r H 2r -,
-OSOO -, - SOO -, - SOOC r H 2r -, - C r
_{H 2r -N (C p H 2p} + 1) -SOO -, - C r H 2r -N (C
_{p H 2p + 1) -CO- (} r, r ' 1 each independently represent an integer of up to 20, p is from 0 to 4 representing an integer .s are each (C _s H _2s O) to 1 to 10 independently
Represents an integer, and t represents an integer from 1 to 6. ) Represents.

[0023] R is _{-O- (C q H 2q -O)} w -C q 'H
_{2q '+ 1, - (C} q H 2q -O) w -C q' H 2q '+ 1, -C q H 2q
_{-R ', - O-C q} H 2q -R', - COO-C q H 2q -
_{R ', - OCO-C q} H 2q -R' (R ' is -Cl, -
_{F, -CF 3, -NO 2,} -CN, -H, -COO-C q '
_{H 2q '+ 1, -OCO-} C q'' represents _{+ 1, q, q' H} 2q each independently represents an integer of 1 to 20. w is 1 to 10
Represents the integer. ), R may be linear or branched.

[0024] Rf is _{- (C x F 2x O)} z C y F 2y is _{+ 1,} x 1 is independently in each of the (C _x F _2x O) 10
Is an integer from 1 to 10, y is an integer from 1 to 10,
z is an integer from 1 to 10. )

Further, specific structural examples of the perfluoroether liquid crystal compound include compounds having the following structures.

[0026]

Embedded image

[0027]

Embedded image

[0028]

Embedded image

The specific perfluoro compound contained in the liquid crystal composition of the present invention is specifically as follows.
The compounds having the structures shown below may be mentioned. (Note that the present invention is not limited to the exemplified compounds below.)

[0030]

[Chemical 6]

[0031]

[Chemical 7]

[0032]

Embedded image

[0033]

Embedded image

As the liquid crystal, at least a fluorine-containing liquid crystal compound having a fluorocarbon terminal portion and a hydrocarbon terminal portion, the both terminal portions being bound by a central nucleus, and having a smectic mesophase or a latent smectic mesophase, One or more compounds having one or more ether oxygens in the chain (perfluoroether liquid crystal compounds) and at least one or more of the specific perfluoro compounds are essentially contained. By containing these two kinds of compounds, good driving characteristics can be obtained characteristically in a wide temperature range.

To obtain these effects, at least one kind of non-liquid crystalline perfluoro compound is 0.01% by weight.
It is preferable that it is contained above. Further, in order to obtain sufficient contrast and response speed, a bookshelf or a structure having a small layer inclination angle close thereto is preferable, and for this reason, 50% by weight or more of a perfluoroether liquid crystal compound is contained in the liquid crystal composition of the present invention. It is preferably contained. Further, a perfluoroalkyl liquid crystal compound can be contained from the viewpoint of good compatibility with the perfluoroether liquid crystal compound. Furthermore, a so-called hydrocarbon type liquid crystalline compound having no perfluorocarbon chain can be contained as another component. The liquid crystal composition used in the present invention contains a chiral compound.

In the present invention, the liquid crystal composition contains
Other compounds such as dyes, pigments, antioxidants, UV absorbers and other additives may also be included.

The liquid crystal element of the present invention constitutes a liquid crystal device having various functions. The data format and SY which are image information having scanning line address information shown in FIGS. 2 and 3.
A liquid crystal display device is realized by using communication synchronization means using N signals. The reference numerals in the figure are as follows.

101 chiral smectic liquid crystal display device 102 graphic controller 103 display panel 104 scanning line driving device 105 information line driving device 106 decoder 107 scanning signal generating device 108 shift register 109 line memory 110 information signal generating device 111 driving control circuit 112 GCPU 113 Host CPU 114 VRAM

The image information is generated by the graphic controller 102 on the main body side, and transferred to the display panel 103 according to the signal transfer means shown in FIGS. The graphic controller 102 is a CPU
(Central processing unit, abbreviated as GCPU) and VRAM
(Image information storage memory) Host CPU 1 with 114 as a core
13 manages image information and communicates with the liquid crystal display device 101. Note that a light source is disposed on the back surface of the display panel.

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

As a method of driving the liquid crystal element of the present invention, for example, JP-A-59-193426 and JP-A-59-19.
The driving method disclosed in Japanese Patent No. 3427, Japanese Patent Application Laid-Open No. 60-156046, Japanese Patent Application Laid-Open No. 60-156047 or the like can be applied.

FIG. 6 is an example of a waveform diagram of the above driving method. Further, FIG. 5 is a plan view of an example of a chiral smectic liquid crystal panel in which matrix electrodes are arranged. FIG.
In the liquid crystal panel 51, the scanning lines of the scanning electrode group 52 and the data lines of the information electrode group 53 are wired so as to intersect with each other, and the chiral smectic liquid crystal is arranged between the scanning lines and the data lines at the intersections. Has been done.

In FIG. 6A, S _S is a selected scan waveform applied to the selected scan line, S _N is a non-selected scan waveform not selected, and I _S is applied to the selected data line. selection information waveform (black), I _N represents the non-selection information signal applied to the data line which is not selected (white). In the figure the _{(I S -S S) (I} N -S S) is the voltage waveforms applied to pixels on a selected scanning line, the voltage (I _S -S _S) is applied pixel black take the display state, the voltage (I _N -
The pixel to which S _S ) is applied takes a white display state.

FIG. 6B shows the drive waveform shown in FIG. 6A, which is a time-series waveform when the display shown in FIG. 4 is performed.

In the driving example shown in FIG. 6, the minimum application time Δt of the single polarity voltage applied to the pixel on the selected scanning line.
Corresponds to the time of the write phase t _{2, and} the time of the 1-line clear t ₁ phase is set to 2Δt.

The values of the parameters V _S , V _I and Δt of the drive waveform shown in FIG. 6 are determined by the switching characteristics of the liquid crystal material used.

FIG. 7 shows the change of the transmittance T, that is, the V-T characteristic when the drive voltage (V _S + V _I ) is changed while keeping the bias ratio described later constant. Where Δ
t = 50 μsec, bias ratio V _I / (V _I + V _S ) = 1
It is fixed at / 3. The positive side of FIG. 7 is shown in FIG. 6 (I
_N -S _S), the negative side waveform shown by (I _S -S _S) is applied.

Here, V ₁ and V ₃ are called the actual driving threshold voltage and the crosstalk voltage, respectively. Also, V ₂ <V ₁ <V ₃
At this time, ΔV = (V ₃ −V ₁ ) / (V ₃ + V ₁ ) is called a voltage margin, which is a parameter of the voltage width capable of matrix driving. It can be said that V ₃ is generally present in driving a chiral smectic liquid crystal display device. Specifically, FIG.
A voltage value causing switching by V _B in waveform _{(A) (I N -S S} ). Of course, it is possible to increase the value of V ₃ by increasing the bias ratio, increasing the bias ratio corresponds to a large amplitude of a data signal, an increase in flickering in image quality, contrast Is undesirably caused.

According to our study, the bias ratio is 1/3 to 1/4.
The degree was practical. By the way, if the bias ratio is fixed, the voltage margin ΔV strongly depends on the switching characteristics of the liquid crystal material and the element configuration, and it goes without saying that an element having a large ΔV is very advantageous for matrix driving.

Similarly, the above voltage is kept constant,
It is also possible to drive by changing the voltage application time Δt. The above voltage may be used as the voltage application time as it is, and at this time, the voltage application time threshold is Δt.
₁ , the voltage application time crosstalk value is Δt _2, and (Δ
t ₂ −Δt ₁ ) / (Δt ₂ + Δt ₁ ) = ΔT is called a voltage application time margin.

At such a certain constant temperature, two states of "black" and "white" can be written in the selected pixel depending on two directions of the information signal, and the non-selected pixel has the "black" or "white" state. The voltage margin or the voltage application time margin capable of maintaining the “white” state is unique because there is a difference depending on the liquid crystal material and the element configuration. Also,
Since the drive margin shifts even if the environmental temperature changes, in the case of an actual display device, it is necessary to set the optimal driving conditions for the liquid crystal material, the element configuration, and the environmental temperature.

[0052]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples.

The compounds used are described below.

[0054]

Embedded image

[0055]

Embedded image

The liquid crystal cell has a glass substrate with ITO and NMP / nBC = 2 / of polyimide precursor LP64 manufactured by Toray Industries, Inc.
1 solution was spin-coated and baked to form a polyimide,
Rubbed. In addition, three types of film thickness of the polyimide film, which is the orientation control layer, were prepared: 300Å, 200Å, and 50Å. The opposite substrate was a glass substrate with ITO, which was spin-coated with a silane coupling agent (octadecyltriethoxysilane) and heat-treated. A silica bead spacer was sprinkled on the above two substrates, the gap was adjusted, and the substrates were bonded together to form a liquid crystal cell having a thickness of 2.0 μm.

As the liquid crystal composition, the above-mentioned compound A:
B: C: D: E: F: G, 50: 15: 10: 15:
Composition X, 50: 1, mixed in a ratio of 3: 5: 2.
Composition Y was a mixture of 5: 10: 15: 3: 5: 0.

The bookshelf property (BS property) of the layer structure of each liquid crystal composition immediately after injection at 25 ° C. was generally good.

These liquid crystal elements were driven by using the driving waveform shown in FIG. The bias ratio is 1/3 and (V
_I + V _S ) is fixed at 20V, the voltage application time is variable, and the margin immediately after the liquid crystal is injected into the cell (initial margin) and the margin after leaving at 25 ° C for 100 hours (margin after leaving) are measured and compared. did.

[Examples 2 and Comparative Examples 1 to 4] Liquid crystal compositions X and Y were prepared by using alignment control layers having film thicknesses of 300, 200 and 5, respectively.
A 0 Å cell was injected to measure the initial margin and the margin after standing. The results are shown in the table.

[0061]

[Table 1]

As described above, in Examples 1 and 2 satisfying the requirements of the present invention, the margin is maintained at 85% or more of the initial value even after being left standing. On the other hand, in other examples, it can be seen that the margin after leaving is greatly reduced. Originally, the chiral smectic liquid crystal was equivalently stable on both sides of the bistable, but the direction left was stabilized and the opposite direction became unstable (left monostable). Has decreased.

[Examples 3 to 5, Comparative Examples 5 to 8]

[0064]

[Chemical 12] A: B: C: D: E: F: H = 52: 10: 15: 1
5: 3: 5: 1 with composition P, A: B: C: D: E: F: H = 52: 10: 15: 1
Composition Q, 5: 3: 5: 0, A: B: C: D: E: F: I = 52: 10: 15: 1
5: 3: 5: 0.5 with composition R, A: B: C: D: E: F: J = 52: 10: 15: 1
The composition S is 5: 3: 5: 2.

These were injected into the cells prepared previously, and the initial margin and the margin after standing were measured.

The results are shown in the table below.

[0067]

[Table 2]

[0068]

As described above, according to the liquid crystal device of the present invention, a chiral smectic liquid crystal device of high brightness can be realized by exhibiting a structure of a bookshelf or a layer having a small layer tilt angle, and further higher. It has a great effect on reliability, especially on monostable storage.

[Brief description of drawings]

FIG. 1 is a diagram showing a cross-sectional view of a liquid crystal element of the present invention.

FIG. 2 is a block diagram illustrating a display device including a liquid crystal element of the present invention and a graphics controller.

FIG. 3 is a diagram showing a timing chart of image information communication between a display device and a graphics controller.

FIG. 4 is a schematic diagram of a display pattern when actual driving is performed with the time-series driving waveform shown in FIG.

FIG. 5 is a plan view of a liquid crystal panel in which matrix electrodes are arranged.

FIG. 6 is a diagram showing an example of drive waveforms used to drive the liquid crystal element of the present invention.

FIG. 7 is a graph (VT characteristic diagram) showing a change in transmittance when a drive voltage is changed according to the present invention. 1 Liquid crystal layer 2 Substrate 3 Transparent electrode 4 Alignment control layer 5 Sealing material 6 Lead wire 7 Signal power source 8 Polarizing plate 9 Light source 101 Chiral smectic liquid crystal display device 102 Graphic controller 103 Display panel 104 Scan line driving device 105 Information line driving device 106 Decoder 107 Scan Signal Generator 108 Shift Register 109 Line Memory 110 Information Signal Generator 111 Drive Control Circuit 112 GCPU 113 Host CPU 114 VRAM

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koichi Sato 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Shinichi Nakamura 3-30-2 Shimomaruko, Ota-ku, Tokyo Kya Non non corporation

Claims (8)

[Claims] 1. An upper and lower substrate having at least electrodes and an orientation control layer, and at least one orientation control layer having a thickness of 200.
Å or less, and the liquid crystal has a fluorocarbon end portion and a hydrocarbon end portion, both end portions thereof are bound by a central nucleus, and a fluorine-containing liquid crystal compound group having a smectic phase or potentially a smectic phase And 70% by weight or more of the liquid crystal compound containing 30% by weight or more of the liquid crystal compound containing at least one ether oxygen in the chain in the fluorocarbon end chain of the fluorine-containing liquid crystal compound, A perfluoro compound having an optionally branched carbon chain having 2 to 30 carbon atoms having at least one perfluoro carbon, wherein one or more methylene groups in the carbon chain is -Y-, -YCO
-, -COY-, -CO-, -OCOO-, -CH = C
It may be replaced with H- or -C≡C- (Y is O or S.), and -OH or -NR is present in any of the carbon chains.
R '(R and R'represent the same or different hydrogen, or an alkyl group having 1 to 5 carbon atoms) or -COOH.
May be substituted, and α (α is a phenyl group which may be substituted with one or more —OH, —NH ₂ , —CN, and —F) is substituted at the terminal portion. A liquid crystal device, which is a chiral smectic liquid crystal composition containing a good compound. 2. The liquid crystal device according to claim 1, wherein the amount of the perfluoro compound added is 0.01 to 5% by weight with respect to the entire liquid crystal composition. 3. A compound containing at least one linkage of ether oxygen in the fluorocarbon terminal chain of said fluorine-containing liquid crystal _{compound, -D (C x F 2x O} ) z C y F
_{2y + 1} (x is 1 to 1 independently for each (C _x F _2x O)
An integer of 0, y is an integer of 1 to 10, and z is 1 to 10
Of an integer, D is a single _{bond, -COO-C r H 2r -} , -
_{O-C r H 2r -,} - O- (C s H 2s O) t -C r 'H 2r' -,
_{-OSO 2 -, - SO 2 -} , - SO 2 -C r H 2r -, - C r
_{H 2r -, - C r H} 2r -N (C p H 2p + 1) -SO 2 -, - C r
_{H 2r -N (C p H 2p} + 1) -CO-, r and r 'are each independently an integer of from 1 to 20, s is each (C _s
H _2s O) is independently an integer of 1 to 10, t is an integer of 1 to 6, and p is an integer of 0 to 4). The liquid crystal element according to claim 1. 4. The compound containing at least one ether oxygen in the chain in the fluorocarbon terminal chain among the fluorine-containing liquid crystal compounds is a compound represented by the following general formula I-1. The liquid crystal element described. [General Formula I-1] And a, b, and c each independently represent 0 or an integer of 1 to 3. However, a + b + c is at least 2. A, B
Can be in either direction, and independently, -CO
O-, -COS-, -COSe-, -COTe-,-
_{(CH 2 CH 2) k -} (k represents an integer of 1 to 4), -
C≡C -, - CH = CH - , - CH = N -, - CH 2 -
Represents O-, -CO-, -O-, and a single bond. X, Y and Z are independently -H, -Cl, -F, -Br, -I,-.
_{OH, -OCH 3, -CH 3,} -CF 3, -OCF 3, -C
N, representing the -NO _2. l, m, and n are 0 independently.
Represents an integer of 4. D is _{-COO-C r H 2r -,} - O-C r
_{H 2r -, - O (C} s H 2s O) t -C r 'H 2r' -, - C r H 2r
-, - OSOO -, - SOO -, - SOOC r H 2r -,
_{-C r H 2r -N (C p} H 2p + 1) -SOO -, - C r H 2r -
_{N (C p H 2p + 1} ) -CO- (r, r ' represents an integer of from independently 1 to 20, p is an integer from 0 to 4 .s are each (C _s H _2s O) independently represents an integer of 1 to 10, and t represents an integer of 1 to 6.)
Represents R is _{-O- (C q H 2q -O)} w -C q 'H 2q' + 1,
_{- (C q H 2q -O)} w -C q 'H 2q' + 1, -C q H 2q -R ',
_{-O-C q H 2q -R '} , - COO-C q H 2q -R', - O
_{CO-C q H 2q -R '} (R' is -Cl, -F, -CF _{3,
-NO 2, -CN, -H, -COO} -C q 'H 2q' + 1, -O
CO-C _q represents a _{'H 2q' + 1, q} , q ' each independently represents an integer of from 1 to 20. w represents an integer of 1 to 10. ), R may be linear or branched. Rf is-
_{(C x F 2x O) z} C y F 2y is _{+ 1,} x is each (C _x
F _2x O) is an integer from 1 to 10 independently, and y is 1
Is an integer from 1 to 10, and z is an integer from 1 to 10. ) 5. The liquid crystal device according to claim 5, wherein the compound represented by the general formula I-1 is a compound having a phenylpyrimidine core. 6. The liquid crystal device according to claim 1, wherein the alignment control layer has a film thickness of 100 Å or less. 7. The liquid crystal device according to claim 1, wherein the alignment control layer has a film thickness of 50 Å or less. 8. A liquid crystal device using the liquid crystal element according to claim 1.