JPH04295446A - Liquid crystal compound, liquid crystal composition containing the same compound and liquid crystal element - Google Patents

Abstract

PURPOSE:To obtain a new liquid crystal compound effective for improving contrast while satisfying conditions required for producing a ferroelectric liquid crystal composition. CONSTITUTION:A liquid crystal compound shown by formula I (R<1> is 1-15C alkyl or alkyloxy; R<2> is 3-10C alkyl) such as 4'-octyloxybiphenyl-4-carboxylic acid 4-(2-ethylhexyloxycarbonyl)phenyl. The compound shown by formula I, for example, is obtained by reacting a 4'-alkylbiphenyl-4-carboxylic acid shown by formula II or a 4'-alkyloxybiphenyl-4-carboxylic acid with phosphorus pentachloride to give an acid chloride shown by formula III and reacting this compound with a 4-hydroxybenzoic acid 2-ethylalkyl shown by formula IV in the presence of pyridine in a toluene solvent.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal compound, a liquid crystal composition containing the same, and a liquid crystal element.

0002

[Prior Art] Currently, liquid crystal display elements are used in a wide range of fields such as watches, calculators, office automation equipment such as word processors and personal computers, and pocket televisions. This is what was used. As a liquid crystal display device using nematic liquid crystal, twisted nematic type (Twisted nematic type) is used.
d Nematic TN type) liquid crystal display device, super twisted type (Supertwisted Bir
effrence effect, SBE type) liquid crystal display devices, etc.

However, twisted nematic liquid crystal display devices have the drawback that as the number of scanning lines increases, the driving margin becomes narrower, making it impossible to obtain sufficient contrast, making it difficult to produce large-capacity display devices. . Super twisted nematic (STN) type liquid crystal display elements and double layer super twisted nematic (DSTN) type liquid crystal display elements have been developed to improve this TN type liquid crystal display element, but as the number of lines increases, contrast and response speed deteriorate. As a result, the display capacity is currently limited to about 800×1024 lines.

On the other hand, thin film transistors (TFTs) are formed on the substrate.
) has also been developed, making it possible to display large-capacity displays such as 1,000 x 1,000 lines, but the manufacturing process is long, yields are likely to drop, and manufacturing costs are extremely high. It has the following drawbacks. Furthermore, this method is considered difficult to fabricate a large capacity display element such as 2000×2000 lines due to restrictions due to the mobility of the semiconductor.

[0005] However, the demand for display devices in the world is moving toward higher resolution.
In particular, DTP (Desk Top Publishing)
ng), EWS (Engineering Work
WYSIWIG (W
what you see is what you see
The concept of ``et'' is being emphasized. this is,
The concept is to display the same thing as what is printed out on the display device. The resolution of current laser printers is about 400 DPI (400 dots/inch), so in order to realize the WYSIWYG concept, a display device that is at least A4 size or larger and has a resolution of 2000 x 2000 or more is required.

As mentioned earlier, it is difficult to achieve a resolution of 2000 x 2000 or more with conventional liquid crystal display devices that utilize the nematic phase; Ferroelectric liquid crystal display elements (Appl. Phys. Lett., 36,
899 (1980); JP-A-56-107216; US Pat. No. 4,367,924). This liquid crystal display element differs from the above-mentioned field effect type nematic liquid crystal display device that utilizes the dielectric anisotropy of liquid crystal molecules. It is a switching liquid crystal display element.

This display method uses chiral smectic C phase, chiral smectic I phase, and chiral smectic F phase.
This method utilizes a ferroelectric liquid crystal phase such as a ferroelectric liquid crystal phase. In this ferroelectric liquid crystal device, when ferroelectric liquid crystal is injected into a cell with a thin cell gap, the helical structure of the ferroelectric liquid crystal unravels under the influence of the interface, and the liquid crystal molecules are tilted at an angle θ with respect to the normal to the smectic layer. There is a coexistence of a region that is stable when tilted by -θ and a region that is stable when tilted by -θ in the opposite direction, and has bistability. When a voltage is applied to this ferroelectric liquid crystal element, the orientation of the liquid crystal molecules and their spontaneous polarization can be uniformly aligned, and by switching the polarity of the applied voltage, the orientation of the liquid crystal molecules can be changed from one certain state to another. Switching to a certain state becomes possible. With this switching, birefringent light changes in the ferroelectric liquid crystal in the cell, so by sandwiching the ferroelectric liquid crystal element between two polarizers, transmitted light can be controlled. Furthermore, even if the voltage application is stopped, the orientation of the liquid crystal molecules is maintained in the state before the voltage application was stopped due to the alignment regulating force of the interface, so that a memory effect can also be obtained.

[0008] Furthermore, the time required for switching drive is
Since the spontaneous polarization of the liquid crystal and the electric field act directly, a high-speed response of 1/1000 or less of that of a twisted nematic liquid crystal display device is possible. As mentioned above, the characteristics of this ferroelectric liquid crystal element include bistability, memory performance, and high-speed response. Therefore, using this ferroelectric liquid crystal, it is possible to construct a high-resolution liquid crystal display device with a large number of scanning lines using a multiplex drive method, and since it does not require active elements such as thin film transistors, manufacturing is possible. It has the advantage that the cost does not increase. In addition, ferroelectric liquid crystal elements also have the advantage of wide viewing angles, making WYSIWIG (
What you see is what you see
etc. ) is seen as a highly promising device for large-capacity display.

[0009]

[Problems to be Solved by the Invention] Ferroelectric liquid crystal elements have the above-mentioned advantages, but it is difficult to achieve flicker-free, high-contrast display in large-capacity display elements having 1000 x 1000 or more scanning lines. If you try to do so, the following problems will arise. In other words, one method for flicker-free display is 16.7msec (60Hz
), but in this case, the ferroelectric liquid crystal material is required to have an extremely fast response speed. For example, in the case of a display element with 1000 scanning lines, a high-speed response of 8.4 μsec is required, as can be seen from the following equation. 16.7 (msec) ÷ 1000 ÷ 2 = 8.
4 μsec (Here, it is divided by 2 because in the case of ferroelectric liquid crystal, at least 2 pulses are required for writing.)

For this reason, in the research and development of ferroelectric liquid crystal materials to date, the realization of high-speed response has been a major goal. Previous research has shown that in order to improve response speed, it is possible to create a ferroelectric liquid crystal composition by adding a chiral compound with large spontaneous polarization to a low-viscosity non-chiral liquid crystal composition that exhibits a smectic C phase. It turned out to be a good thing. For this reason, many efforts have been made to develop optically active compounds with extremely large spontaneous polarization (for example, the 16th Liquid Crystal Symposium, 1K
101, 1K102, 1K111, 1K112,
1K114, 1K115, 1K116, 1K1
17, 1K119, 3K106, (1990),
), On the other hand, also in non-chiral liquid crystal compositions, there is knowledge that pyrimidine compounds are preferable due to their low viscosity (for example; Onishi et al., National Technical
Report, 33, 35 (1987). ) was obtained.

However, it is currently not easy to achieve the required response speed by improving ferroelectric liquid crystal materials. Furthermore, if we take into account that in order to create a display element with a larger capacity, the response speed must be further increased, it becomes quite difficult to increase the capacity by increasing the speed of the liquid crystal material. It's easy to imagine.

[0012] As a powerful method to solve such problems, a method called partial rewriting (Kanbe, Institute of Electronics, Information and Communication Engineers Special Seminar Proceedings "Optoelectronics" - Liquid Crystal Displays and Related Materials -, 1990) January,
p18-26) are proposed. This method accesses only the parts of the screen that need to be rewritten. This enables a display element that can follow movements of a mouse, etc., which require high speed when displaying graphics.

However, when attempting to obtain a flicker-free display using this partial rewriting method, a bias voltage of 1/3 of the writing voltage is applied to pixels that are not to be rewritten (hereinafter, this driving method will be described). (referred to as 1/3 bias drive method). This driving method is described in Japanese Patent Application Laid-open No. 64-593, for example.
The biggest problem when using this 1/3 bias method, as proposed in Publication No. 89, is that 1/3 bias voltage is applied even to pixels that are not rewritten, and because of this bias voltage, no rewriting is performed. This means that the molecules of pixels that do not carry out this process will fluctuate, resulting in a decrease in contrast. For example, a ferroelectric liquid crystal display prototyped by Canon using the partial rewriting method achieved a contrast of only 5:1 (Kanbe, Institute of Electronics, Information and Communication Engineers Special Seminar Proceedings ``Optoelectronics'' - Liquid Crystal Display and Related Materials, January 1990, p. 18-26). In addition, we have previously created display devices by combining various ferroelectric liquid crystal compositions with liquid crystal elements of various configurations, but the contrast obtained when displaying using the 1/3 bias driving method The value was about 1.5 to 8, and the product was extremely unsatisfactory.

[0014] In order to solve such contrast problems, it is necessary to apply a suitable liquid crystal material to a ferroelectric liquid crystal element with a suitable configuration. From this point of view, there is a need for a novel liquid crystal compound useful for improving contrast, a liquid crystal composition using the same, and a liquid crystal element. In addition, compounds applicable to ferroelectric liquid crystal elements include:
It is easy to exhibit a stable smectic C phase, it is easy to exhibit a smectic A phase or a nematic phase, or both on the high temperature side of the smectic C phase, its melting point is not very high, it is chemically stable, and it is resistant to light. be stable, have no coloration, not have high viscosity, have an appropriate tilt angle in the smectic C phase,
etc. are required.

The present invention was made under these circumstances, and provides a novel liquid crystal compound that is effective in improving contrast while satisfying the above-mentioned conditions necessary for producing a ferroelectric liquid crystal composition as much as possible. The purpose is to provide

[0016]

According to the present invention, there are provided a compound represented by the general formula (I), a liquid crystal composition containing the same, and a liquid crystal element.

[0017]

[Formula 2] (wherein, R1 is a linear or branched alkyl group having 1 to 15 carbon atoms, or an alkyloxy group, and R2 is a linear or branched chain having 3 to 10 carbon atoms. In the definition of general formula (I), straight-chain or branched alkyl groups include methyl, ethyl, propyl, i-propyl, butyl, i-butyl, pentyl, 1- or 2-methylbutyl. , hexyl, 1- or 3-methylpentyl,
heptyl, 1- or 4-methylhexyl, octyl, 1
-Methylheptyl, nonyl, 1- or 6-methyloctyl, decyl, 1-methylnonyl, undecyl, 1-methyldecyl, dodecyl, 1-methylundecyl, and the like.

Further, the linear or branched alkyloxy group in the definition of general formula (I) includes those in which an ether group is bonded to the above-mentioned alkyl group. The carbon chain of these alkyl groups or alkyloxy groups may contain an asymmetric carbon. Furthermore, one or more hydrogen atoms in these alkyl groups or alkyloxy groups may be substituted with a fluorine atom, chlorine atom, bromine atom, cyano group, nitro group, trifluoromethyl group, methoxy group, etc. .

Examples of compounds represented by general formula (I) include:

[0020]

[Chemical formula 3] etc. can be mentioned. The compound represented by compound (I) can be prepared, for example, by reacting 4'-alkylbiphenyl-4-carboxylic acid or 4'-alkyloxybiphenyl-4-carboxylic acid of the following formula (II) with phosphorus pentachloride to form acid chloride ( 2-ethylalkyl 4-hydroxybenzoate (I) in a toluene solvent in the presence of pyridine.
V).

[0021]

[Image Omitted] The compound represented by general formula (I) is a stable smectic C
It tends to show smectic A phase. Therefore, it is useful as a component of ferroelectric liquid crystal compositions. Also, due to the effect of the branched ethyl group, the melting point is not high, making it easy to mix with other compounds. It is chemically and light-stable, and has no coloration.

A liquid crystal composition can be prepared by combining the compound represented by the general formula (I) with various compounds in appropriate proportions. The compound represented by general formula (I) is particularly useful when producing a ferroelectric liquid crystal composition. When producing a ferroelectric liquid crystal composition, for example,
It is preferable to combine it with a compound represented by the general formula (V) or (VI).

[0023]

embedded image (wherein, R5 and R6 are the same or different and represent a linear or branched alkyl group or alkyloxy group having 1 to 15 carbon atoms, and m represents an integer of 0 or 1. )still,
It goes without saying that the ferroelectric liquid crystal composition must exhibit a chiral smectic phase and must contain an optically active compound with an appropriate structure.

It goes without saying that the compound of the present invention can be applied to various liquid crystal compositions such as nematic liquid crystal compositions, smectic A liquid crystal compositions, and antiferroelectric liquid crystal compositions. Next, an example in which the compound represented by the general formula (I) is applied to a ferroelectric liquid crystal element will be described.

FIG. 1 is a sectional view showing an example of the liquid crystal element of the present invention. A plurality of transparent electrodes 2a are formed on a glass substrate 1a in a striped manner parallel to each other, an insulating film 3a and an alignment film 4a are formed thereon, and the alignment film 4a is uniaxially aligned by rubbing. Processing is performed to form the substrate 9. On the other hand, the glass substrate 1 on the other side
A plurality of transparent electrodes 2b are formed in parallel to each other in a stripe pattern under similar conditions on b, and an insulating film 3b and an alignment film 4b are formed thereon.
A rubbing alignment process is applied to form the substrate 10.

Next, this substrate 10 and the other substrate 9 are arranged so that the alignment films 4a and 4b face each other, the transparent electrodes 2a and 2b are perpendicular to each other, and the rubbing directions are almost the same. They are pasted together with a sealing member 6 with an interval of about 3 μm between them. A liquid crystal cell 11 is created by interposing a ferroelectric liquid crystal between these substrates 9 and 10. Furthermore,
A polarizing plate 12a whose polarization axis is substantially perpendicular to the top and bottom of this cell.
, 12b are arranged, and the polarization axis of one of the polarizing plates is substantially aligned with the optical axis of either one of the liquid crystals of the cell, thereby forming a liquid crystal display device.

Now, in such a ferroelectric liquid crystal element, the following conditions are required in order to obtain high contrast when driven by the 1/3 bias driving method. First, it is necessary to use alignment films 4a and 4b such that the pretilt angle of liquid crystal molecules at the interface between the liquid crystal and the alignment film is 8° or more. In addition, it is known that the layer structure of the chiral smectic C layer generally has a chevron structure that is twisted in a dogleg shape, and from the relationship with the rubbing direction, the C1 orientation and the C2 orientation are (See Figure 2)
However, in order to obtain high contrast with 1/3 bias driving, C1 orientation is required. Furthermore, it is known that there are uniform (U) orientation and twisted (T) orientation (see Figure 3) based on the molecular orientation within the layer, but in order to obtain high contrast with 1/3 bias driving, must be uniformly oriented. It is also desired that the tilt angle of the ferroelectric liquid crystal material is not larger than the pretilt angle of the liquid crystal molecules at the interface between the liquid crystal and the alignment film by 5° or more.
The composition constituting the liquid crystal composition is also important, and the present inventors have found that the compound represented by general formula (I) is effective.

To summarize the above, the pretilt angle of the liquid crystal molecules at the interface between the liquid crystal and the alignment film is set to 8° or more, the tilt angle of the ferroelectric liquid crystal composition is set not to be larger than that by 5° or more, and the general formula (I ) Using a ferroelectric liquid crystal composition containing a compound represented by The present inventors have found that it can be obtained.

Of course, liquid crystal elements in which a liquid crystal composition containing at least one type of general formula (I) can be used are not limited to the above-mentioned ferroelectric liquid crystal elements, but also ferroelectric liquid crystal elements having other configurations, or Needless to say, it can be applied to liquid crystal devices using a nematic phase (TN, STN, DSTN, etc.), liquid crystal devices using a smectic A phase (thermal writing, electroclinic, etc.), antiferroelectric liquid crystal devices, and the like.

[0030]

[Example] (Example 1) 3.5 g (0.0168 mol) of phosphorus pentachloride was added to 5.0 g (0.0153 mol) of 4'-octyloxybiphenyl-4-carboxylic acid, and the mixture was heated to about 80°C.
was heated to cause a reaction. The generated POCl3 and excess phosphorus pentachloride were distilled off under reduced pressure to obtain 4'-octyloxybiphenyl-4-carboxylic acid chloride. This was dissolved in 50 ml of toluene, and 4.2 g (0.0168 mol) of 2-ethylhexyl 4-hydroxybenzoate and 5 ml of pyridine (dehydrochlorination agent) were added. After being left at room temperature for 10 hours, the mixture was kept at 70° C. for 3 hours, and then cooled to room temperature. Then add ice and hydrochloric acid and extract with ether. The ether layer was washed with NaHCO3 aqueous solution and then water, and Na2SO4
Dry with. The ether was distilled off, the residue was purified by column chromatography (silica gel, solvent chloroform), and recrystallized from a mixed solvent of ethanol and toluene to obtain the desired 4
'-octyloxybiphenyl-4-carboxylic acid 4-(2
-Ethylhexyloxycarbonyl)phenyl (Compound No. 101) was obtained as a racemate.

[0031]

embedded image The infrared absorption spectrum of this compound is shown in FIG. Also,
The transition temperature (°C) of this compound was as follows. C SC SA N
I・73・120・148・−
・(Note) C: Crystal phase SC: Smectic C phase SA: Smectic A phase N: Nematic phase I: Isotropic liquid phase (Example 2) Compound No. 1 synthesized in Example 1. 101, optically active compound No. 1 shown in Table 1 was added. Ferroelectric liquid crystal composition No. 201 was added in an amount of 1% by weight. 301 was produced.

[0032]

[Table 1] Abbreviations in the table have the following meanings. C: Crystal phase SB: Smectic B phase SF: Smectic F phase SC: Smectic C phase SA: Smectic A phase I: Isotropic liquid was successively injected into a ferroelectric liquid crystal cell having an ITO electrode under the following conditions.

Alignment film: LX-1400 (polyimide manufactured by Hitachi Chemical) Rubbing: Parallel cell thickness: 2 μm Rectangular wave (V=±20V, f=0
．． The tilt angle was measured by applying a frequency of 5 Hz) and observing under a polarizing microscope. FIG. 5 shows a graph in which the tilt angle is plotted against the temperature.

(Example 3) Compound N synthesized in Example 1
o. 101 and compound No. 1 shown in Table 1. Optically active compound No. 202 shown in Table 1 was added to the two-component composition with No. 202.
A ferroelectric liquid crystal composition was prepared by adding 1% by weight of each of No. 201. These ferroelectric liquid crystal compositions were injected into a ferroelectric liquid crystal cell having an ITO electrode under the following conditions.

Alignment film: LX-1400 (polyimide manufactured by Hitachi Chemical) Rubbing: Parallel cell thickness: 2 μm Rectangular wave (V=±20V, f=0
．． The tilt angle was measured by applying a frequency of 5 Hz) and observing under a polarizing microscope. Additionally, the transition temperature of the composition was measured using a polarizing microscope. In FIG. 6, phase transition temperature and tilt angle are plotted against composition. It can be seen that the tilt angle decreases due to mixing. C
It can be seen that this is preferable for achieving a 1U orientation and achieving high contrast with 1/3 bias driving.

(Example 4) Compound No. in Example 3
．． 202 as compound no. The tilt angle was measured in the same manner as in Example 3 except that the angle was changed to 207. The results are shown in FIG. (Example 5) Compound No. 3 in Example 3. 202 was converted into Compound No. 202 in Table 2. The tilt angle was measured in the same manner as in Example 3 except that the angle was changed to 212.

[0037]

[Table 2] The results are shown in FIG. (Example 6) Compound No. 3 in Example 3. 202 was converted into Compound No. 202 in Table 2. The tilt angle was measured in the same manner as in Example 3 except that the angle was changed to 213. The results are shown in FIG.

(Example 7) Compound No. in Example 3
．． 202 was converted into Compound No. 202 in Table 2. Other than changing to 214,
The tilt angle was measured in the same manner as in Example 3. The results are shown in Figure 1.
0. (Example 8) Compound No. synthesized in Example 1. A ferroelectric liquid crystal composition having a composition shown in Table 3 was prepared using No. 101 and the compounds shown in Table 1 or Table 2. This composition exhibited a chiral smectic C phase at room temperature. The transition temperatures are also shown in Table 3.

[Table 3]

(Example 9) A ferroelectric liquid crystal element having the structure shown in FIG. 1 was manufactured. A plurality of ITO transparent electrodes 2a having a thickness of 1000 Å are arranged in stripes parallel to each other on a glass substrate 1a, and an insulating film 3 is formed on the glass substrate 1a.
500 Å of SiO2 is formed as a film, and then an alignment film 4 is formed.
As a, PSI-X-A-2001 (polyimide manufactured by Chisso Petrochemical Co., Ltd., pretilt angle = 12 to 15 degrees) was formed to a thickness of 400 Å using a spin coater, and then uniaxially coated by rubbing with a rayon-based cloth. An alignment treatment was performed to form a substrate 9. On the other hand, the glass substrate 1b on the other side
The substrate 10 was also formed by processing under the same conditions.

Next, this substrate 9 and the other substrate 10
are made of epoxy resin with an interval of 1.5 μm interposed between them so that the alignment films 4a and 4b face each other, the transparent electrodes 2a and 2b are orthogonal to each other, and the rubbing directions are almost the same. They were bonded together using a sealing member 6. Between these substrates 9 and 10, ferroelectric liquid crystal composition No. 1 prepared in Example 1 was inserted through the injection port using a vacuum injection method. 101
After each injection, the injection port was cured with an acrylic UV-curable resin to produce a liquid crystal cell 11. Further, there are polarizing plates 12a whose polarization axes are substantially orthogonal to each other above and below this cell.
12b, and the polarizing axis of one of the polarizing plates was made to substantially match the optical axis of either one of the liquid crystals of the cell, thereby forming a liquid crystal display device.

When the orientation of these ferroelectric liquid crystal elements was investigated, it was found that in the temperature range from the smectic C-smectic A transition point to room temperature, a C2 orientation with a small area surrounded by minute zigzag defects was observed. Except for the area,
The entire surface had C1U orientation. The tilt angle θ and memory angle θM in the chiral smectic C phase of these ferroelectric liquid crystal elements were measured. The tilt angle θ was defined as 1/2 of the angle between two extinction positions obtained by applying a ±10 V rectangular wave to the liquid crystal cell. The memory angle θM was defined as 1/2 of the angle between the two memory states obtained when a voltage having the waveform shown in FIG. 11 was applied. θ, θM, and θM/θ were plotted against temperature (FIG. 13).

Voltage of waveform shown in FIG. 11 (V=±20V)
was applied and the memory pulse width was measured. The memory pulse width was set to the minimum pulse width that allowed bistable switching. Figure 1 by setting the pulse width to the memory pulse width.
When a waveform of 1 was applied, a contrast of 30 or more was obtained. The voltage of the 1/3 bias waveform shown in Figure 12 (V=
±20V) was applied, and the memory pulse width was measured. The memory pulse width was set to the minimum pulse width that allowed bistable switching. The results are shown in FIG. Furthermore, when the pulse width was set to the memory pulse width and the waveform shown in FIG. 12 was applied, a high contrast of 15 to 30 was obtained. In this case, a good black state can be maintained even when bias is applied, and it can be concluded that the fluctuation of molecules due to bias voltage is suppressed.

Further, as is clear from FIG. 13, the tilt angle θ of the liquid crystal is 16° or less, which is not so large compared to the pretilt angle. This small tilt angle is considered to be one of the reasons why the C1U orientation appears, and in this orientation, good bistable switching can be achieved and high contrast can be obtained. (Example 10) Compound No. synthesized in Example 1. 101
A ferroelectric liquid crystal composition having a composition shown in Table 4 was prepared using the compounds shown in Table 1. These compositions exhibited a chiral smectic C phase at room temperature. The transition temperature is also shown in Table 4.

[0044]

[Table 4] These ferroelectric liquid crystal compositions were injected into a ferroelectric liquid crystal cell having an ITO electrode under the following conditions. Alignment film: LX-1400 (polyimide manufactured by Hitachi Chemical) Rubbing: Parallel cell thickness: 2 μm Spontaneous polarization was measured by the triangular wave method and plotted against temperature (FIG. 14).

[0045]

Effects of the Invention Compound (I) of the present invention exhibits a not so high melting point, tends to exhibit stable smectic C phase and smectic A phase, and also exhibits an appropriate tilt angle in the smectic C phase, and is chemically It is also stable against light. Therefore, compound (I) is useful as a component of liquid crystal compositions, and by combining it with other compounds, various liquid crystal compositions including various ferroelectric liquid crystal compositions can be prepared. Applicable to various liquid crystal elements. In particular, C1U
When creating a ferroelectric liquid crystal device using orientation, 1/
High contrast can be obtained even in 3-bias driving.

[Detailed explanation of drawings]

FIG. 1 is an explanatory diagram of the configuration of a ferroelectric liquid crystal element of the present invention.

FIG. 2 is an explanatory diagram of the chevron layer structure and C1 orientation and C2 orientation of the chiral smectic C phase.

FIG. 3 is an explanatory diagram of uniform orientation and twisted orientation.

FIG. 4 is a diagram illustrating an infrared absorption spectrum of the compound of the present invention.

FIG. 5 is a diagram showing the relationship between tilt angle and temperature of a ferroelectric liquid crystal composition using the compound of the present invention.

FIG. 6 is a diagram showing the transition temperature and tilt angle of a ferroelectric liquid crystal composition using the compound of the present invention.

FIG. 7 is a diagram showing the transition temperature and tilt angle of a ferroelectric liquid crystal composition using the compound of the present invention.

FIG. 8 is a diagram showing the transition temperature and tilt angle of a ferroelectric liquid crystal composition using the compound of the present invention.

FIG. 9 is a diagram showing the transition temperature and tilt angle of a ferroelectric liquid crystal composition using the compound of the present invention.

FIG. 10 is a diagram showing the transition temperature and tilt angle of a ferroelectric liquid crystal composition using the compound of the present invention.

FIG. 11 is a diagram showing applied voltage waveforms.

FIG. 12 is a diagram showing applied voltage waveforms.

FIG. 13 is a diagram showing temperature changes in memory angle, chilled angle, and memory pulse width of a ferroelectric liquid crystal element according to an example of the present invention.

FIG. 14 is a diagram showing spontaneous polarization of a ferroelectric liquid crystal composition using the compound of the present invention.

[Explanation of symbols]

1a, 1b Glass substrate 2a, 2b
Transparent electrodes 3a, 3b Electrode protective film 4a,
4b Orientation film 6 Seal member
7 Liquid crystal 9, 10 board
11 Liquid crystal cells 12a, 12b Polarizing plate 13 Smectic layer 17,
18 Chevron structure 19 Rubbing direction 20 Liquid crystal molecules: N director 21
C director 22 Pretilt angle 23 C1 orientation 24 C2 orientation

Claims (3)

[Claims] Claim 1 General formula (I): [Formula 1] (wherein, R1 is a linear or branched alkyl group having 1 to 15 carbon atoms, or an alkyloxy group, and R2 is a linear or branched alkyl group having 1 to 15 carbon atoms; An alkyl group having a branched chain and having 3 to 10 carbon atoms. 2. A liquid crystal composition comprising at least one liquid crystal compound represented by the general formula (I) according to claim 1. 3. A ferroelectric liquid crystal device using the liquid crystal composition according to claim 2.