JPH06298760A - Liquid crystal compound, liquid crystal composition containing the same, liquid crystal element using the same, displaying method using them and display device therefor - Google Patents

Abstract

PURPOSE:To obtain the subject new compound having high-speed responsiveness, effective for raising contrast. CONSTITUTION:A compound of formula I [R is group of formula II ((a) is 1-7; X3 is O, OCO or COO or H; X1 and X2 are H or fluoro atom] such as a compound of having a structural formula of formula III. The compound of formula I is obtained by making thiophene-2-carboxylic acid or thiophene-2- carboxylic acid chloride and a corresponding 4-(5-alkylpyrimidin-2-yl)phenol derivative into an ester, synthesizing.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a novel liquid crystalline compound,
The present invention relates to a liquid crystal composition containing the liquid crystal compound, a liquid crystal element using the liquid crystal composition, a display device and a display method using the liquid crystal composition and the liquid crystal element, and more specifically, a response characteristic to an electric field is improved. The present invention also relates to a novel liquid crystal composition, a liquid crystal display device using the same, a liquid crystal device used in a liquid crystal-optical shutter, and the like, and a display device and a display method using the liquid crystal device for display.

[0002]

2. Description of the Related Art Conventionally, liquid crystals have been applied as electro-optical elements in various fields. Most of the liquid crystal elements currently in practical use are, for example, M.Schad.
t) and W. Helfrich's “Applied Physics”
Letters "Vo.18, No.4 (1971.2.15) P.127-128" Volta
geDependent Optical Activity of a Twisted Nematic
liquid crystal ") TN (Twisted Nematic)
The liquid crystal of the type is used.

These are based on the dielectric alignment effect of liquid crystals, and utilize the effect that the average molecular axis direction is directed in a specific direction by an applied electric field due to the dielectric anisotropy of liquid crystal molecules. . However, the optical response speed of these devices is said to be limited to milliseconds, which is too slow for many applications. On the other hand, in the application to a large flat panel display, the drive by the simple matrix method is the most effective in consideration of the price and the productivity. In the simple matrix system, an electrode configuration in which a scan electrode group and a signal electrode group are configured in a matrix is adopted, and for driving thereof, an address signal is sequentially and selectively selected and applied to the scan electrode group, Employs a time-division driving method in which a predetermined information signal is synchronized with an address signal and selectively applied in parallel.

However, when the above-mentioned TN type liquid crystal is adopted for the element of such a driving system, the scanning electrode is selected and the signal electrode is not selected, or the scanning electrode is not selected and the signal electrode is selected. A finite electric field is applied to the region (so-called “half-selected point”). The difference between the voltage applied to the selected point and the voltage applied to the half-selected point is sufficiently large,
Further, if the voltage threshold value required to align the liquid crystal molecules perpendicularly to the electric field is set to an intermediate voltage value, the display element operates normally, but the number of scanning lines (N) is increased. When this is done, the time (du) during which the effective electric field is applied to one selection point while scanning the entire screen (1 frame).
ty ratio) decreases at a rate of 1 / N.

For this reason, the voltage difference as an effective value applied to the selected point and the non-selected point in the case of repeating scanning becomes smaller as the number of scanning lines increases, and as a result, the image contrast is lowered or Crosstalk is an inevitable drawback. Such a phenomenon is caused by a liquid crystal having no bistability (a stable state in which the liquid crystal molecules are aligned horizontally with respect to the electrode surface, and is aligned vertically only while an electric field is effectively applied. ) Using the temporal accumulation effect (ie,
This is an inherently unavoidable problem that occurs when repeatedly scanning). To improve this point, the voltage averaging method, 2
The frequency drive method and the multi-matrix method have already been proposed, but none of them is sufficient, and the increase in the screen size and the density of the display element are stopped because the number of scanning lines cannot be increased sufficiently. This is the current situation.

In order to improve the drawbacks of the conventional liquid crystal device, the use of a liquid crystal device having bistability has been proposed by Clark and Lagerwall (Japanese Patent Laid-Open No. 56-56). 107216, U.S. Pat. No. 4,367,924, etc.). Bistable liquid crystals are generally chiral smectic C phase (SmC ^* phase)
Alternatively, a ferroelectric liquid crystal having an H phase (SmH ^* phase) is used. This ferroelectric liquid crystal has a bistable state composed of a first optical stable state and a second optical stable state with respect to an electric field, and therefore, the optical modulation element used in the above-mentioned TN type liquid crystal. Unlike, for example, the liquid crystal is oriented in the first optically stable state with respect to one electric field vector, and the liquid crystal is oriented in the second optically stable state with respect to the other electric field vector. Further, this type of liquid crystal has a property (bistability) of taking one of the above two stable states in response to an applied electric field and maintaining that state when no electric field is applied.

In addition to the above-mentioned characteristic of having bistability, the ferroelectric liquid crystal has an excellent characteristic of high-speed response. This is because the spontaneous polarization of the ferroelectric liquid crystal and the applied electric field act directly to induce the transition of the alignment state, which is 3 to 4 orders faster than the response speed due to the action of the dielectric anisotropy and the electric field. As described above, the ferroelectric liquid crystal potentially has extremely excellent characteristics, and by utilizing such characteristics, it is quite essential for many problems of the above-mentioned conventional TN type element. Improvement is obtained. In particular, it is expected to be applied to high-speed optical optical shutters and high-density, large-screen displays. For this reason, there has been extensive research on ferroelectric liquid crystal materials, but the ferroelectric liquid crystal materials that have been developed to date are used for liquid crystal elements including low-temperature operating characteristics, high-speed response, contrast, and the like. It is hard to say that it has sufficient characteristics.

Between the response time τ, the magnitude Ps of spontaneous polarization and the viscosity η, the following equation (II) (However, E is an applied electric field). Therefore, there are the following methods for increasing the response speed. (A) Increasing the magnitude Ps of spontaneous polarization (b) Decreasing the viscosity η (c) Increasing the applied electric field E However, the applied electric field has an upper limit because it is driven by an IC or the like, and it is desirable to be as low as possible. . Therefore, it is actually necessary to reduce the viscosity η or increase the value of the spontaneous polarization magnitude Ps.

Generally, in a ferroelectric chiral smectic liquid crystal compound having a large spontaneous polarization, the internal electric field of the cell caused by the spontaneous polarization is also large, and there is a tendency that there are many restrictions on the device structure capable of assuming a bistable state. Further, even if the spontaneous polarization is unnecessarily increased, the viscosity tends to increase accordingly, and as a result, it is considered that the response speed does not become so fast. Further, generally, in the case of a liquid crystal element utilizing the birefringence of liquid crystal, the transmittance under a crossed Nicols is represented by the following formula (IIa). In the formula (IIa), I ₀ is the incident light intensity, I is the transmitted light intensity, θ
_a is the apparent tilt angle defined below, Δn is the refractive index anisotropy, d is the thickness of the liquid crystal layer, and λ is the wavelength of incident light. Apparent tilt angle θ _a in the aforementioned non-helical structure
Will appear as the angle in the average molecular axis direction of the twisted liquid crystal molecules in the first and second alignment states. (II
According to a) formula, the tilt angle theta _a apparent becomes the maximum transmittance at an angle of 22.5 °, the tilt angle theta _a apparent in the non-helical structure for realizing bistability 22.5 ° It is necessary to be as close as possible to.

However, when it is applied to the ferroelectric liquid crystal having a non-helical structure exhibiting the bistability, which was announced by Clark and Laguwell, it has the following problems and causes a decrease in contrast. Has become. First, the apparent tilt angle θ _a (1/2 of the angle formed by the molecular axes of two stable states) in a non-helical ferroelectric liquid crystal obtained by aligning with a conventional rubbing-treated polyimide film. However, the transmittance is low because it is smaller than the tilt angle (1/2 angle θ of the triangular pyramid shown in FIG. 4) in the ferroelectric liquid crystal.

Secondly, even if the contrast is high in the static state where no electric field is applied, when a drive display is performed by applying a voltage, liquid crystal molecules fluctuate due to a minute electric field during a non-selection period in matrix drive, which causes black. Becomes faint. As described above, in order to put a ferroelectric liquid crystal device into practical use, a liquid crystal composition having a high-speed response and a chiral smectic phase with high contrast is required. Furthermore, the spontaneous polarization of the liquid crystal composition, the chiral smectic C pitch, the Ch pitch, and the temperature at which the liquid crystal phase is taken for uniform switching of the display, good viewing angle characteristics, low-temperature storage stability, and reduction of load on the driving IC. It is necessary to optimize the range, optical anisotropy, tilt angle and dielectric anisotropy.

[0012]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to have a high-speed response and a high contrast so that the above-mentioned ferroelectric liquid crystal device can be put to practical use. A liquid crystal compound containing the liquid crystal compound, a liquid crystal composition containing the liquid crystal compound, particularly a liquid crystal composition exhibiting a ferroelectric chiral smectic phase, a liquid crystal device using the liquid crystal composition, and a display using the same A method and a display device are provided.

[0013]

The above objects can be achieved by the present invention described below. That is, the present invention provides a liquid crystal compound represented by the following general formula (I), a liquid crystal composition containing the same, a liquid crystal element using the same, a display method and a display device using the same. is there. .

[Chemical 7] (R in the formula is hydrogen or a linear or branched alkyl group having 1 to 18 carbon atoms, and 1
One or two or more non-adjacent two or more methylene groups are -O-,
-S-, -CO-, -COO-, -OOC-, -CH =
It may be replaced by either CH- or -C≡C-, and the hydrogen atom in the alkyl group may be replaced by a fluorine atom. X ₁ and X ₂ are H,
Indicates any one of F, Cl, Br, CH ₃ , CF ₃ and CN. )

[0014]

The novel liquid crystalline compound of the present invention is a known compound (for example, 5-alkylthiophenone-2-carboxylic acid-4- (5-alkylpyrimidin-2-yl) phenyl ester derivative (JP-A-2-196785). And a constituent material of a liquid crystal element that can be effectively applied to high-speed response and high contrast. Further, a display device in which such a liquid crystal element is used as a display element and is combined with a light source, a driving circuit and the like becomes a good device.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail with reference to preferred embodiments. The liquid crystal compound of the present invention is
It is synthesized by esterification of thiophene-2-carboxylic acid or thiophene-2-carboxylic acid chloride and the corresponding 4- (5-alkylpyrimidin-2-yl) phenol derivative. Among the liquid crystalline compounds represented by the general formula (I), preferable compounds include X ₁ and X _{2 which} are a hydrogen atom, a halogen atom and trifluoro, in view of the temperature range of the liquid crystal phase, miscibility and orientation. A methyl group is preferable, and a hydrogen atom and a fluorine atom are more preferable. Also, R
Is preferably any of the following, more preferably (i), (ii) or (v), and further preferably (i).

[0016]

[Chemical 8] (However, a is an integer of 1 to 17, d, g and i
Is an integer of 0 to 7, b, e and h are integers of 1 to 8, f and k are 0 or 1, and j is an integer of 1 to 15. X ₃ is a single bond, -O-, -OCO
-Or-COO- is shown. ) A specific structural formula of the compound of the present invention is shown below.

[0017]

[Chemical 9]

[0018]

[Chemical 10]

[0019]

[Chemical 11]

[0020]

[Chemical 12]

[0021]

[Chemical 13]

[0022]

[Chemical 14]

[0023]

[Chemical 15]

[0024]

[Chemical 16]

[0025]

[Chemical 17]

The liquid crystal composition of the present invention comprises at least one of the liquid crystal compounds of the present invention represented by the above general formula (I).
It can be obtained by mixing the seed and one or more other liquid crystal compounds in an appropriate ratio. The liquid crystal composition of the present invention is preferably a ferroelectric liquid crystal composition, particularly a ferroelectric chiral smectic liquid crystal composition. Other liquid crystal compounds used in the present invention are represented by the general formulas (III) to (XII
I) shows below.

[0027]

[Chemical 18]

A preferred compound of the formula (III) is (III
a) to (IIIe) can be mentioned.

[Chemical 19]

[0029]

[Chemical 20] Preferred compounds of the formula (IV) include (IVa) to (IVc).

[Chemical 21]

[0030]

[Chemical formula 22]

[0031]

Embedded image Preferred compounds of the formula (V) include (Va) and (Vb).

[0032]

[Chemical formula 24]

Here, R ₁ 'and R ₂ ' have 1 to 18 carbon atoms.
Is a linear or branched alkyl group, and one or two or more non-adjacent —CH ₂ — groups in the alkyl group may be replaced by —CH halogen —. Furthermore, X ₁ or X ₂ directly bonded to -CH ₂ - one except group or not adjacent two or more -CH ₂ - group,

[Chemical 25] May be replaced with. However, R ₁ 'or R ₂ ' represents one CH ₂ group.

[Chemical formula 26] R ₁ 'in the case of an alkyl halide substituted by
Or, R ₂ 'is not bonded to the ring by a single bond.

It is preferable that R ₁ 'and R ₂ ' are as shown in the following i) to ix). i) a straight-chain alkyl group having 1 to 15 carbon atoms

[Chemical 27] (P: any integer from 0 to 5, q: any integer from 2 to 11, and may be optically active.)

[Chemical 28] (R: any integer from 0 to 6, s: 0 or 1, t: 1
It may be an integer of any one of to 14 and may be optically active. )

[Chemical 29] (U: 0 or 1, an integer of v: 1 to 16)

[0035]

[Chemical 30] (W: any integer of 1 to 15 or optically active)

[Chemical 31] (An integer of x: 0 to 2 or y: 1 to 15)

[Chemical 32] (Z: any integer from 1 to 15)

[Chemical 33] (A: any integer from 0 to 2, B: any integer from 1 to 15, or optically active)

[Chemical 34] (C: any integer of 0 to 2, D: any integer of 1 to 15, or optically active)

More preferable compounds (IIIa) to (IIId) include the following (IIIaa) to (IIIdc).

[0037]

[Chemical 35]

[0038]

[Chemical 36]

More preferable compounds (IVa) to (IVc) include the following (IVaa) to (IVcb).

[Chemical 37]

More preferable compounds (Va) to (Vd) include the following (Vaa) to (Vdf).

[0041]

[Chemical 38]

[Chemical Formula 39]

More preferable compounds (VIa) to (VIf) include the following (VIaa) to (VIfa).

[0043]

[Chemical 40]

[0044]

[Chemical 41]

More preferable compounds of (VII) include the following (VIIa) and (VIIb).

[Chemical 42]

More preferred compounds of (VIII) include the following (VIIIa) and (VIIIb).

[Chemical 43]

Further preferred compounds of (VIIIb) are
The following (VIIIba) and (VIIIbb) are mentioned.

[Chemical 44]Where R ' ₃And R ' _FourIs a linear or branched chain having 1 to 18 carbon atoms
A branched alkyl group, one younger
Is two or more -CH that are not adjacent₂-Group is -CH halogen
May be replaced by Furthermore, X ' ₁or
Is X ' ₂-CH directly bonded to₂-One excluding groups or
Two or more -CHs that are not adjacent₂-Groups are
It may have been replaced.

[Chemical formula 45]However, R ' ₃Or R ' _FourIs one -CH_Two-Group is -CH halo
When the halogenated alkyl is replaced by Gen-,
R ' ₃Or R ' _FourIs not a single bond to the ring.

Further, R ' ₃And R ' _FourAre listed below i)
~ Vii) are preferred. i) a linear alkyl group having 1 to 15 carbon atoms,

[Chemical formula 46] (P: any integer of 0 to 5, q: any integer of 2 to 11, or optically active)

[Chemical 47] (R: any integer from 0 to 6, s: 0 or 1, t: 1
It may be an integer of any one of to 14 and may be optically active. )

[0049]

[Chemical 48] (U: 0 or 1, and v: an integer of 1 to 16.)

[Chemical 49] (W: any integer of 1 to 15 or optically active)

[Chemical 50] (A: any integer from 0 to 2, B: any integer from 1 to 15, or optically active)

[Chemical 51] (C: any integer of 0 to 2, D: any integer of 1 to 15, or optically active)

[0050]

[Chemical 52]

[0051]

[Chemical 53]

[0052]

[Chemical 54]

Preferred compounds of (IX) are the following (IX
a) to (IXc).

[Chemical 55]

Preferred compounds of the formula (X) are the following (X
a) and (Xb).

[Chemical 56]

Preferred compounds of (XII) are the following (X
IIa)-(XIIf).

[Chemical 57]

Preferred compounds of (XIII) include the following (XIIIa) to (XIIIe).

[Chemical 58]

More preferred compounds (IXa) to (IXc) include the following (IXaa) to (IXcc).

[Chemical 59]

More preferable compounds of (Xa) and (Xc) include the following (Xaa) to (Xbb).

[0059]

[Chemical 60]

More preferred compounds of (XI) include the following (XIa) to (XIg).

[Chemical formula 61]

More preferred compounds (XIIa) to (XIIf) include the following (XIIaa) to (XIIfc).

[0062]

[Chemical formula 62]

[0063]

[Chemical formula 63]

Here, R ₅ ′ and R ₆ ′ are linear or branched alkyl groups having 1 to 18 carbon atoms, and —CH ₂ — which is directly bonded to X ₁ and X ₂ in the alkyl group. One or two or more non-adjacent —CH ₂ — groups other than a group may be replaced by the following.

[Chemical 64]

Further, R ₅ 'and R ₆ ' are i) listed below.
~ Vi) are preferred. i) a linear alkyl group having 1 to 15 carbon atoms,

[0066]

[Chemical 65] (P: any integer of 0 to 5, q: any integer of 2 to 11, or optically active)

[Chemical formula 66] (R: any integer from 0 to 6, s: 0 or 1, t: 1
It may be an integer of any one of to 14 and may be optically active.

[0067]

[Chemical formula 67] (W: any integer of 1 to 15 or optically active)

[Chemical 68] (A: any integer from 0 to 2, B: any integer from 1 to 15, or optically active)

[Chemical 69] (C: any integer of 0 to 2, D: any integer of 1 to 15, or optically active)

When the liquid crystalline compound of the present invention is mixed with one or more other liquid crystalline compounds described above or the liquid crystal composition, the liquid crystal of the present invention occupies in the liquid crystal composition obtained by mixing. The ratio of the organic compound is 1% by weight to 80% by weight, preferably 1% by weight to 60% by weight, more preferably 1% by weight to 4%.
It is preferably 0% by weight. When two or more liquid crystal compounds of the present invention are used, the proportion of the mixture of two or more liquid crystal compounds of the present invention in the liquid crystal composition obtained by mixing is 1% by weight to 80% by weight, Preferably from 1% by weight
It is preferably 60% by weight. Further, the ferroelectric liquid crystal layer in the ferroelectric liquid crystal device according to the present invention is prepared by heating the liquid crystal composition showing a chiral smectic phase prepared as described above to an isotropic liquid temperature in vacuum, It is preferable that the liquid crystal layer be sealed in a cell and gradually cooled to form a liquid crystal layer and then returned to normal pressure.

FIG. 1 is a schematic sectional view showing an example of a liquid crystal element having a chiral smectic liquid crystal layer of the present invention for the purpose of explaining the structure of the ferroelectric liquid crystal element. In FIG.
Reference numeral 1 is a chiral smectic liquid crystal layer, 2 is a glass substrate, 3 is a transparent electrode, 4 is an insulating alignment control layer, 5 is a spacer, 6 is a lead wire, 7 is a power source, 8 is a polarizing plate, and 9 is a light source. There is. In each of the two glass substrates 2,
_A transparent electrode 3 made of a thin film of ₂ O ₃ , SnO ₂ or ITO (Indium Tin Oxide) is covered. An insulating alignment control layer 4 for arranging liquid crystals in the rubbing direction is formed on top of this by rubbing a polymer thin film such as polyimide with gauze or acetate flocking cloth. Further, as the insulating material, for example, silicon nitride, silicon carbide containing hydrogen, silicon oxide,
An inorganic material insulating layer such as boron nitride, boron nitride containing hydrogen, cerium oxide, aluminum oxide, zirconium oxide, titanium oxide, and magnesium fluoride is formed, and polyvinyl alcohol, polyimide, polyamide is formed thereon. Orient organic insulating materials such as imide, polyester imide, polyparaxylene, polyester, polycarbonate, polyvinyl acetal, polyvinyl chloride, polyvinyl acetate, polyamide, polystyrene, cellulose resin, melamine resin, urea resin, acrylic resin and photoresist resin As the control layer, the insulating orientation control layer 4 may be formed of two layers, or may be a single layer of an inorganic material insulating orientation control layer or an organic material insulating orientation control layer. If this insulating orientation control layer is an inorganic type, it can be formed by a vapor deposition method or the like, and if it is an organic type, a solution in which an organic insulating substance is dissolved or a precursor solution thereof (0.1 to 20% by weight in a solvent, It is preferably 0.2 to 10% by weight), and is applied by a spinner coating method, a dip coating method, a screen printing method, a spray coating method, a roll coating method, or the like, under predetermined curing conditions (for example, under heating). It can be formed by curing.

The layer thickness of the insulating orientation control layer 4 is usually 10Å
1 μm, preferably 10Å to 3000Å, more preferably 10Å to 1000Å are suitable. The two glass substrates 2 are held at an arbitrary interval by a spacer 5. For example, there is a method in which silica beads and alumina beads having a predetermined diameter are used as spacers and sandwiched between two glass substrates, and the periphery is sealed with a sealing material, for example, an epoxy adhesive. Alternatively, a polymer film or glass fiber may be used as a spacer.
A liquid crystal exhibiting ferroelectricity is enclosed between the two glass substrates. The thickness of the chiral smectic liquid crystal layer 1 in which the chiral smectic liquid crystal is enclosed is generally 0.5.
˜20 μm, preferably 1 to 5 μm.

The transparent electrode 3 is connected to the outside by a lead wire.
It is connected to the power supply 7. Also, on the outside of the glass substrate 2,
A polarizing plate 8 is attached. As Figure 1 is a transmissive type,
9 is equipped. Figure 2 shows the operation of a ferroelectric liquid crystal device.
Therefore, the example of the cell is schematically drawn. 21a and
21b are In respectively₂O₃, SnO₂Or ITO (Indium Ti
n Oxide) and other thin film transparent electrodes
(Glass plate) between which the liquid crystal molecular layer 22 is glass
SmC oriented perpendicular to the plane^*Phase or SmH^*Phase of
Liquid crystal is enclosed. The thick line 23 is a liquid crystal molecule.
This liquid crystal molecule 23 is orthogonal to the molecule.
And has a dipole moment (P⊥) 24.
Voltage above a certain threshold between the electrodes on the substrates 21a and 21b
Is applied, the helical structure of the liquid crystal molecule 23 is unwound and
All of the polar moment (P⊥) 24 is oriented toward the electric field
In addition, the liquid crystal molecules 23 can change the alignment direction. liquid
The crystal molecules 23 have an elongated shape, and
It exhibits refractive index anisotropy in the minor axis direction, and thus, for example,
If crossed Nicols polarizers are placed above and below the
Liquid crystal optical modulator whose optical characteristics change depending on the polarity of pressure applied
Is easily understood.

The liquid crystal cell preferably used in the liquid crystal optical modulator of the present invention can be made sufficiently thin (for example, 10 μm or less). As the liquid crystal layer becomes thinner in this way, the helical structure of the liquid crystal molecules unwinds as shown in FIG. 3, and its dipole moment Pa or Pb is upward (34a) or downward (34b). Take either state. When an electric field Ea or Eb having a polarity equal to or higher than a certain threshold is applied to such a cell by the voltage applying means 31a and 31b, the dipole moment is directed upward corresponding to the electric field vector of the electric field Ea or Eb. 34a or the downward direction 34b, and the liquid crystal molecules are changed to the first stable state 33 accordingly.
a or the second stable state 33b.

As described above, there are two advantages of using such a ferroelectric liquid crystal element as an optical modulation element. The first is that the response speed is extremely fast, and the second is that the alignment of the liquid crystal molecules has bistability. The second point will be further described with reference to FIG. 3, for example. When the electric field Ea is applied, the liquid crystal molecules are aligned in the first stable state 33a, but this state is stable even when the electric field is cut off. When a reverse electric field Eb is applied, the liquid crystal molecules are oriented in the second stable state 33b and change their orientation, but they remain in this state even when the electric field is cut off. Also, the applied electric field E
As long as a or Eb does not exceed a certain threshold value, the previous alignment state is still maintained.

FIG. 5 shows a part of the drive waveform used in the present invention. In FIG. 5A, S _S is a selected scanning waveform applied to the selected scanning line, S _N is a non-selected scanning waveform not selected, and I _S is selection information applied to the selected data line. A waveform (black) and _IN indicates a non-selection information signal (white) applied to the unselected data line. In addition, in the figure (I
In _S -S _S) and (I _N -S _S) is the voltage waveform applied to pixels on a selected scanning line, a pixel voltage (I _S -S _S) is applied to take the black display state, the voltage (I _N -S _S) is applied pixel takes the display state of white. FIG. 5B shows (A)
7 is a time-series waveform when the display shown in FIG. 6 is performed.

In the driving example shown in FIG. 5, the minimum application time Δt of the single polarity voltage applied to the pixels on the selected scanning line is
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. Now, Fig. 5
The values of the respective parameters V _S , V _I and Δt of the drive waveform shown in (4) are determined by the switching characteristics of the liquid crystal material used. Here, the bias ratio V _I / (V _I + V _S ) = 1
It is fixed at / 3. Although it is possible to increase the width of the appropriate drive voltage by increasing the bias ratio, increasing the bias ratio means increasing the amplitude of the information signal. Is caused, which is not preferable. In the present invention, the bias ratio of about 1/3 to 1/4 was practical. 6 is shown in FIG.
It is a schematic diagram of a display pattern when actually driving with the time-series drive waveform shown in (B).

The liquid crystal device of the present invention described above is used in the display panel section, and the data format as the image information having the scanning line address information shown in FIGS. 7 and 8 and the SYNC.
The liquid crystal display device of the present invention is realized by taking communication synchronization means by signals.

The image information is generated by the graphics controller 102 on the main unit side and transferred to the display panel 103 in accordance with the signal transfer means shown in FIGS. The graphics controller 102 is a CPU
(Central processing unit, abbreviated as GCPU 112 hereafter) and VRAM (memory for storing image information) 114 are in charge of managing image information and communication between the host CPU 113 and the liquid crystal display device 101, and control method of the present invention. Are mainly implemented on the graphics controller 102. A light source is arranged on the back surface of the display panel.

[0078]

EXAMPLES Next, the present invention will be described more specifically with reference to Examples and Comparative Examples. The present invention is not limited to these examples. <Example 1> Synthesis of display compound I-13

[0079]

[Chemical 70]

In a 100 ml round-bottomed flask, 0.35 g (2.73 mmol) of 2-thiophenecarboxylic acid (I),
0.93 g (2.73 mmol) of 4- (5-dodecylpyrimidin-2-yl) phenol, dichloromethane 20
0.5 ml of N, N'-dicyclohexylcarbodiimide (2.71 m) was added while dissolving with stirring at room temperature.
mol) and 4-dimethylaminopyridine (0.05 g) were sequentially added, and the mixture was stirred at room temperature for 3 hours and 15 minutes. After leaving it at room temperature overnight, the precipitated N, N'-dicyclohexylurea was filtered off, and the filtrate was dried under reduced pressure. The obtained residue was purified by silica gel column chromatography (eluent toluene / ethyl acetate: 100/1) and recrystallized from a toluene-methanol mixed solvent to give 2-thiophenecarboxylic acid 4- (5
0.95 g (yield 77.2%) of -dodecylpyrimidin-2-yl) phenyl ester was obtained. The phase transition temperature of the obtained compound is shown below.

<Examples 2-3> By the same method as in Example 1, the compounds shown in Table 1 were obtained.

[0082]

[Chemical 71]

[Table 1]

Example 4 The following compounds were mixed in the following parts by weight to prepare a liquid crystal composition A.

[0084]

[Chemical 72]

Further, with respect to this liquid crystal composition A, the exemplary compound I-12 synthesized in Example 2 was mixed in the following parts by weight to prepare a liquid crystal composition B.

[Chemical formula 73] The liquid crystal composition B has the following phase transition temperatures.

<Example 5> Two 0.7 mm thick glass plates were prepared, an ITO film was formed on each glass plate, a voltage application electrode was prepared, and SiO ₂ was vapor-deposited on the electrode. It was an insulating layer. A 0.2% isopropyl alcohol solution of a silane coupling agent [KBM-602 manufactured by Shin-Etsu Chemical Co., Ltd.] was applied on a glass plate for 15 seconds by a spinner having a rotation speed of 2,000 rpm to perform surface treatment. Was applied. After that, heat drying treatment was performed at 120 ° C. for 20 minutes. Further, a 1.5% dimethylacetamide solution of a polyimide resin precursor [SP-510 manufactured by Toray Industries, Inc.] was spun on a glass plate having an ITO film, which had been surface-treated, at a rotation speed of 2,000.
It was applied with a spinner of 0 rpm for 15 seconds. After the film formation, a heat condensation baking treatment was carried out at 300 ° C. for 60 minutes. At this time, the film thickness of the coating film was about 250Å.

The film after firing was rubbed with an acetate flocked cloth, washed with an isopropyl alcohol solution, and silica beads having an average particle size of 2 μm were sprinkled on one of the glass plates, and then each glass plate was washed. The rubbing treatment axes were made parallel to each other, the glass plates were laminated using an adhesive sealant [Rixon bond manufactured by Chisso Corporation], and dried by heating at 100 ° C. for 60 minutes to prepare a cell. The liquid crystal composition B mixed in Example 4 was injected into this cell in an isotropic liquid state, and the temperature was 20 ° C./h from the isotropic phase to 25 ° C.
A ferroelectric liquid crystal device was prepared by cooling the mixture to room temperature. When the cell thickness of this cell was measured with a Berek phase plate, it was about 2 μm.

Using this ferroelectric liquid crystal device, the magnitude Ps of spontaneous polarization and the peak-to-peak voltage Vpp = 2.
By applying a voltage of 0 V, an optical response (change in transmitted light amount 0 to 90%) under a crossed Nicols was detected, and a response speed (hereinafter referred to as an optical response speed) was measured. The results are shown below.

[Table 2]

Comparative Example 1 With respect to the liquid crystal composition A synthesized in Example 4, 5-ethylthiophene-2-carboxylic acid 4- (5-undecylpyrimidin-2-yl) phenyl ester is shown below. By mixing in parts by weight, a liquid crystal composition C was prepared.

[Chemical 74] The liquid crystal composition C exhibits the following phase transition temperatures.

A ferroelectric liquid crystal device was prepared in the same manner as in Example 5 except that the liquid crystal composition C was injected into the cell, and the spontaneous polarization magnitude Ps and the optical response speed were measured.
The results are shown below.

[Table 3]

<Example 6> Two 0.7 mm thick glass plates were prepared, an ITO film was formed on each of the glass plates, a voltage application electrode was prepared, and SiO ₂ was vapor-deposited thereon. It was an insulating layer. A 0.2% isopropyl alcohol solution of a silane coupling agent [KBM-602 manufactured by Shin-Etsu Chemical Co., Ltd.] was applied on a glass plate for 15 seconds by a spinner having a rotation speed of 2,000 rpm to perform surface treatment. Was applied. After that, heat drying treatment was performed at 120 ° C. for 20 minutes. Further, a 1.0% dimethylacetamide solution of a polyimide resin precursor [Toray Industries, Inc .: SP-510] was spun on a glass plate with an ITO film, which had been surface-treated, at a rotational speed of 3,000.
It was applied with a spinner of 0 rpm for 15 seconds. After the film formation, a heat condensation baking treatment was carried out at 300 ° C. for 60 minutes. The film thickness of the coating film at this time was about 120Å.

The coating film after firing was rubbed with an acetate flocked cloth, and then washed with an isopropyl alcohol solution, and silica beads having an average particle size of 1.5 μm were dispersed on one glass plate, The rubbing axes were made parallel to each other, and the glass plates were laminated using an adhesive sealant [Rixon bond manufactured by Chisso Corporation], and dried by heating at 100 ° C. for 60 minutes to prepare a cell. . When the cell thickness of this cell was measured with a Berek phase plate, it was about 1.5 μm. The liquid crystal composition B mixed in Example 4 was injected into this cell in an isotropic liquid state and gradually cooled from the isotropic phase to 25 ° C. at 20 ° C./h to prepare a ferroelectric liquid crystal device. . By using this ferroelectric liquid crystal element, the drive waveform (1/3
As a result of measuring the contrast at the time of driving at 30 ° C. with a bias ratio), it was 19.8.

Comparative Example 2 A ferroelectric liquid crystal device was prepared in the same manner as in Example 6 except that the liquid crystal composition C mixed in Comparative Example 1 was injected into the cell. The contrast at the time of driving at 30 ° C. was measured.
As a result, the contrast was 8.3.

Example 7 The polyamic acid [LQ1802 manufactured by Hitachi Chemical Co., Ltd.] was used instead of the 1.0% dimethylacetamide solution of the polyimide resin precursor used in Example 6.
1% NMP solution was used to prepare a ferroelectric liquid crystal device in the same manner as in Example 6 except that the composition was baked at 270 ° C. for 1 hour, and the contrast at 30 ° C. was measured in the same manner as in Example 6. . As a result, the contrast was 67.3.

Comparative Example 3 A ferroelectric liquid crystal device was manufactured in the same manner as in Example 7, except that the liquid crystal composition C used in Comparative Example 1 was used instead of the liquid crystal composition B used in Example 7. Was prepared and the contrast at 30 ° C. was measured by the same method as in Example 6. As a result, the contrast is 18.5.
Met.

Example 8 The following compounds were mixed in the following parts by weight to prepare a liquid crystal composition D.

[0097]

[Chemical 75]

[0098]

[Chemical 76] Further, with respect to this liquid crystal composition D, the following exemplary compounds were mixed in the respective parts by weight shown below to prepare a liquid crystal composition E.

[0099]

[Chemical 77] A ferroelectric liquid crystal device was prepared in the same manner as in Example 6 except that this liquid crystal composition E was used, and the contrast at the time of driving at 30 ° C. was measured using the same drive waveform as in Example 6. . As a result, the contrast was 21.5.

Comparative Example 4 A ferroelectric liquid crystal device was prepared in the same manner as in Example 6 except that the liquid crystal composition D mixed in Example 8 was used, and the same drive waveform as in Example 6 was used. Was used to measure the contrast during driving at 30 ° C.
As a result, the contrast was 6.7.

<Comparative Example 5> The following exemplary compounds were mixed with the liquid crystal composition D in the following parts by weight,
A liquid crystal composition F was prepared.

[0102]

[Chemical 78] A ferroelectric liquid crystal device was prepared in the same manner as in Example 6 except that this liquid crystal composition F was used, and the contrast at the time of driving at 30 ° C. was measured using the same driving waveform as in Example 6. . As a result, the contrast was 5.8.

From Example 5 and Comparative Example 1, it was found that the liquid crystal composition according to the present invention gave a faster response than the case of using the known compound. Furthermore, Examples 6 to 8,
From Comparative Example 2, Comparative Example 3 and Comparative Example 5, it was found that the liquid crystal composition according to the present invention was a liquid crystal component exhibiting higher contrast than when the known compound was used.

Example 9 The following exemplary compounds were mixed with the liquid crystal composition D in the following parts by weight,
A liquid crystal composition G was prepared.

[Chemical 79] A ferroelectric liquid crystal device was prepared in the same manner as in Example 6 except that this liquid crystal composition G was used, and the contrast at the time of driving at 30 ° C. was measured using the same driving waveform as in Example 6. . As a result, the contrast was 19.2.

Example 10 Instead of the exemplified compounds I-7, I-28 and I-64 used in Example 9, the following exemplified compounds were mixed in the following parts by weight to prepare a liquid crystal composition H.
It was created.

[Chemical 80] A ferroelectric liquid crystal device was prepared in the same manner as in Example 6 except that this liquid crystal composition H was used, and the driving waveform was the same as in Example 6, and the contrast during driving at 30 ° C. was measured. . As a result, the contrast was 17.5.

Example 11 Instead of the exemplary compounds I-17, I-38 and I-46 used in Example 10, the following exemplary compounds were mixed in the following parts by weight to prepare a liquid crystal composition J. Created.

[Chemical 81] A ferroelectric liquid crystal element was prepared in the same manner as in Example 6 except that this liquid crystal composition J was used, and the contrast at the time of driving at 30 ° C. was measured using the same driving waveform as in Example 6. . As a result, the contrast was 16.1.

As is clear from Examples 9 to 11, it has been found that the ferroelectric liquid crystal devices containing the liquid crystal compositions G, H and J according to the present invention can obtain high contrast during driving.

Example 12 A polyvinyl alcohol resin [manufactured by Kuraray Co., Ltd.] was used instead of the 1.0% dimethylacetamide solution of the polyimide resin precursor used in Example 9.
25. PVA-117] A ferroelectric liquid crystal device was prepared by the same method except that a 2% aqueous solution was used, and the contrast at 30 ° C. was measured by the same method as in Example 6;
It was 3.

<Example 13> SiO used in Example 9
_A ferroelectric liquid crystal device was prepared in the same manner as in Example 8 except that the alignment control layer was formed only with a polyimide resin without using _2, and the contrast at 30 ° C. was obtained in the same manner as in Example 6. The measurement result was 17.8.

<Example 14> Instead of the 1.0% dimethylacetamide solution of the polyimide resin precursor used in Example 9, a polyamic acid [Hitachi Chemical Co., Ltd .: LQ180] was used.
[2] 1% NMP solution was used, and a ferroelectric liquid crystal device was prepared in the same manner as in Example 9 except that it was baked at 270 ° C. for 1 hour, and contrast at 30 ° C. was obtained in the same manner as in Example 6. The result was 55.6.

As is clear from the results of Examples 12, 13 and 14, even when the element structure was changed, the element containing the ferroelectric liquid crystal composition of the present invention showed a high contrast as in Example 9. Has been obtained. Further, as a result of detailed examination even when the drive waveform was changed, it was found that similarly a device containing the ferroelectric liquid crystal composition of the present invention can obtain higher contrast.

[0112]

As described above, if the liquid crystalline compound of the present invention exhibits a chiral smectic phase by itself, it becomes a material that can be effectively applied to a device utilizing ferroelectricity. When the liquid crystal composition having the liquid crystalline compound of the present invention exhibits a chiral smectic phase, a display device containing the liquid crystal composition can be operated by utilizing the ferroelectricity of the liquid crystal composition. I can. The ferroelectric liquid crystal that can be used as described above has a good switching characteristic, and by using the ferroelectric liquid crystal, a liquid crystal element having a high-speed response and a high contrast can be obtained. Furthermore, when the liquid crystal element of the present invention is used as a display element and is combined with a light source, a drive circuit, etc., a good display device is obtained.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of an example of a liquid crystal element using a liquid crystal exhibiting a chiral smectic phase.

FIG. 2 is a perspective view schematically showing an example of an element cell for explaining the operation of a liquid crystal element utilizing the ferroelectricity of liquid crystal.

FIG. 3 is a perspective view schematically showing an example of an element cell for explaining the operation of a liquid crystal element utilizing the ferroelectricity of liquid crystal.

FIG. 4 is an explanatory diagram showing a tilt angle (θ).

FIG. 5 is a waveform diagram of a driving method used in this example.

FIG. 6 is a schematic diagram of a display pattern when actual driving is performed with the time-series driving waveform shown in FIG.

FIG. 7 is a signal transfer means of the display device of the present invention.

FIG. 8 is a data format of image information having scanning line address information.

[Explanation of symbols]

 1: Liquid crystal layer having chiral smectic phase 2: Glass substrate 3: Transparent electrode 4: Insulating orientation control layer 5: Spacer 6: Lead wire 7: Power supply 8: Polarizing plate 9: Light source Io: Incident light I: Transmission Light 21a: Substrate 21b: Substrate 22: Liquid crystal layer having chiral smectic phase 23: Liquid crystal molecule 24: Dipole moment (P⊥) 31a: Voltage applying means 31b: Voltage applying means 33a: First stable state 33b: Second Stable state 34a: upward dipole moment 34b: downward dipole moment Ea: upward electric field Eb: downward electric field 101: ferroelectric liquid crystal display device 102: graphics controller 103: display panel 104: scanning line drive circuit 105: Information line drive circuit 106: Decoder 107: Scan signal generation circuit 108: Shift register 10 : Line memory 110: the information signal generating circuit 111: drive control circuit 112: GCPU 113: Host CPU 114: VRAM

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinichi Nakamura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yoko Yamada 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Ikuro Nakazawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (31)

[Claims] 1. A liquid crystalline compound represented by the following general formula (I): [Chemical 1] (R in the formula is hydrogen or a linear or branched alkyl group having 1 to 18 carbon atoms, and 1
One or two or more non-adjacent two or more methylene groups are -O-,
-S-, -CO-, -COO-, -OOC-, -CH =
It may be replaced by either CH- or -C≡C-, and the hydrogen atom in the alkyl group may be replaced by a fluorine atom. X ₁ and X ₂ are H,
Indicates any one of F, Cl, Br, CH ₃ , CF ₃ and CN. ) 2. R in the general formula (I) is represented by the following formula (i) to
The liquid crystalline compound according to claim 1, which is any of (vii). [Chemical 2] [Chemical 3] (However, a is an integer of 1 to 17, d, g and i
Is an integer of 0 to 7, b, e and h are integers of 1 to 8, f and k are 0 or 1, and j is an integer of 1 to 15. X ₃ is a single bond, -O-, -OCO
-Or-COO- is shown. ) 3. The liquid crystal compound according to claim 1, wherein both X ₁ and X ₂ in the general formula (I) are H. 4. _One of X ₁ and X _{2 in} the general formula (I) is H.
And the other is F, The liquid crystal compound according to claim 1. 5. The liquid crystal compound according to claim 1, wherein both X ₁ and X _{2 in} formula (I) are F. 6. The liquid crystal compound according to claim 1, wherein the liquid crystal compound represented by the general formula (I) is an optically active compound. 7. The liquid crystal compound according to claim 1, wherein the liquid crystal compound represented by the general formula (I) is a non-optically active compound. 8. A liquid crystal composition containing at least one kind of the liquid crystal compound according to claim 1. 9. The liquid crystal composition according to claim 8, which contains 1 to 80% by weight of the liquid crystal compound represented by the general formula (I) with respect to the liquid crystal composition. 10. The liquid crystal composition according to claim 8, wherein the liquid crystal compound represented by the general formula (I) is contained in an amount of 1 to 60% by weight based on the liquid crystal composition. 11. The liquid crystal composition according to claim 8, wherein the liquid crystal compound represented by the general formula (I) is contained in an amount of 1 to 40% by weight based on the liquid crystal composition. 12. The liquid crystal composition according to claim 8, which has a chiral smectic phase. 13. A liquid crystal device comprising the liquid crystal composition according to claim 8 disposed between a pair of electrode substrates. 14. The liquid crystal device according to claim 13, further comprising an alignment control layer provided on the electrode substrate. 15. The liquid crystal device according to claim 14, wherein the alignment control layer is a layer that has been subjected to a rubbing treatment. 16. The liquid crystal device according to claim 13, wherein the pair of electrode substrates are arranged with a film thickness in which the spiral of liquid crystal molecules is released. 17. A display device comprising the liquid crystal element according to claim 13. 18. The display device according to claim 17, further comprising a drive circuit for the liquid crystal element. 19. The display device according to claim 17, further comprising a light source. 20. A display method comprising using a liquid crystal composition containing at least one liquid crystal compound represented by the following general formula (I) for display. [Chemical 4] (R in the formula is hydrogen or a linear or branched alkyl group having 1 to 18 carbon atoms, and 1
One or two or more non-adjacent two or more methylene groups are -O-,
-S-, -CO-, -COO-, -OOC-, -CH =
It may be replaced by either CH- or -C≡C-, and the hydrogen atom in the alkyl group may be replaced by a fluorine atom. X ₁ and X ₂ are H,
Indicates any one of F, Cl, Br, CH ₃ , CF ₃ and CN. ) 21. R in the general formula (I) is represented by the following formula (i):
21. The display method according to claim 20, which is any one of to (vii). [Chemical 5] (However, a is an integer of 1 to 17, d, g and i
Is an integer of 0 to 7, b, e and h are integers of 1 to 8, f and k are 0 or 1, and j is an integer of 1 to 15. X ₃ is a single bond, -O-, -OCO
-Or-COO- is shown. ) 22. In the general formula (I), X ₁ and X ₂ are both H
The display method according to claim 20, wherein 23. The display method according to claim 20, wherein _one of X ₁ and X _{2 in} the general formula (I) is H and the other is F. 24. In the general formula (I), X ₁ and X ₂ are both F
The display method according to claim 20, wherein 25. The display method according to claim 20, wherein the liquid crystal compound represented by formula (I) is an optically active compound. 26. The display method according to claim 20, wherein the liquid crystal compound represented by formula (I) is a non-optically active compound. 27. The display method according to claim 20, wherein the liquid crystal composition contains the liquid crystalline compound represented by the general formula (I) in an amount of 1 to 80% by weight. 28. The display method according to claim 20, wherein the liquid crystal composition contains 1 to 60% by weight of the liquid crystal compound represented by the general formula (I). 29. The display method according to claim 20, wherein the liquid crystal composition contains 1 to 40% by weight of the liquid crystal compound represented by the general formula (I). 30. The display method according to claim 20, wherein the liquid crystal composition has a chiral smectic phase. 31. A liquid crystal device comprising a liquid crystal composition containing at least one liquid crystal compound represented by the following general formula (I) disposed between a pair of electrode substrates, and used for display. How to display. [Chemical 6] (R in the formula is hydrogen or a linear or branched alkyl group having 1 to 18 carbon atoms, and 1
One or two or more non-adjacent two or more methylene groups are -O-,
-S-, -CO-, -COO-, -OOC-, -CH =
It may be replaced by either CH- or -C≡C-, and the hydrogen atom in the alkyl group may be replaced by a fluorine atom. X ₁ and X ₂ are H,
Indicates any one of F, Cl, Br, CH ₃ , CF ₃ and CN. )