Liquid crystal display device

Abstract

The subject is to show a liquid crystal display device that has characteristics such as a short response time, a large voltage holding ratio, a low threshold voltage, a large contrast ratio, a long service life and a small flicker rate. The disclosure relates to a liquid crystal display device including an electrode group formed on one or both of a pair of substrates that are opposed to each other, and a plurality of active devices connected to the electrode group, and a liquid crystal alignment film formed on the opposing surfaces of the pair of substrates, and a liquid crystal composition sandwiched in between the pair of substrates, and the liquid crystal composition includes at least one compound selected from the group of compounds represented by formula (1) as a first component. ##STR00001##

Claims

1. A liquid crystal display device comprising an electrode group formed on one or both of a pair of substrates that are opposed to each other, and a plurality of active devices connected to the electrode group, and a liquid crystal alignment film formed on the opposing surfaces of the pair of substrates, and a liquid crystal composition sandwiched in between the pair of substrates, and the liquid crystal composition comprises at least one compound selected from the group of compounds represented by formula (1) as a first component: ##STR00126## in formula (1), R.sup.1 is alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons or alkenyl having 2 to 12 carbons; ring A is 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene, pyrimidine-2,5-diyl, 1,3-dioxane-2,5-diyl or tetrahydropyran-2,5-diyl; Z.sup.1 is a single bond, ethylene, carbonyloxy or difluoromethyleneoxy; X.sup.1 and X.sup.2 are independently hydrogen or fluorine; Y.sup.1 is fluorine, chlorine, alkyl having 1 to 12 carbons in which at least one hydrogen has been replaced by halogen, alkoxy having 1 to 12 carbons in which at least one hydrogen has been replaced by halogen or alkenyloxy having 2 to 12 carbons in which at least one hydrogen has been replaced by halogen; and a is 1, 2, 3 or 4; the liquid crystal alignment film includes a polymer polymerized from at least one compound selected from the group of compounds represented by formula (PAN-1), formula (PAN-2), and formula (PDI-1) to formula (PDI-8): ##STR00127## ##STR00128## in formula (PDI-1) to formula (PDI-8), a group can be bonded to any one of carbon atoms constituting a ring when the bonding position of the group is not fixed to any one of the carbon atoms; R.sup.8 is CH.sub.3, OCH.sub.3, CF.sub.3 or COOCH.sub.3; and h is an integer from 0 to 2.

2. The liquid crystal display device according to claim 1, wherein the first component is at least one compound selected from the group of compounds represented by formula (1-1) to formula (1-34): ##STR00129## ##STR00130## ##STR00131## ##STR00132## ##STR00133## in formula (1-1) to formula (1-34), R.sup.1 is alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons or alkenyl having 2 to 12 carbons.

3. The liquid crystal display device according to claim 1, wherein the ratio of the first component is in the range of 10% by weight to 90% by weight based on the weight of the liquid crystal composition.

4. The liquid crystal display device according to claim 1, wherein the liquid crystal composition comprises at least one compound selected from the group of compounds represented by formula (2) as a second component: ##STR00134## in formula (2), R.sup.2 and R.sup.3 are independently alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbons, alkyl having 1 to 12 carbons in which at least one hydrogen has been replaced by halogen or alkenyl having 2 to 12 carbons in which at least one hydrogen has been replaced by halogen; ring B and ring C are independently 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene or 2,5-difluoro-1,4-phenylene; Z.sup.2 is a single bond, ethylene or carbonyloxy; and b is 1, 2 or 3.

5. The liquid crystal display device according to claim 4, wherein the second component is at least one compound selected from the group of compounds represented by formula (2-1) to formula (2-13): ##STR00135## ##STR00136## in formula (2-1) to formula (2-13), R.sup.2 and R.sup.3 are independently alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbons, alkyl having 1 to 12 carbons in which at least one hydrogen has been replaced by halogen or alkenyl having 2 to 12 carbons in which at least one hydrogen has been replaced by halogen.

6. The liquid crystal display device according to claim 4, wherein the ratio of the second component is in the range of 10% by weight to 90% by weight based on the weight of the liquid crystal composition.

7. The liquid crystal display device according to claim 1, wherein the liquid crystal composition comprises at least one compound selected from the group of compounds represented by formula (3) as a third component: ##STR00137## in formula (3), R.sup.4 and R.sup.5 are independently alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbons, alkenyloxy having 2 to 12 carbons or alkyl having 1 to 12 carbons in which at least one hydrogen has been replaced by halogen; ring D and ring F are independently 1,4-cyclohexylene, 1,4-cyclohexenylene, 1,4-phenylene, 1,4-phenylene in which at least one hydrogen has been replaced by fluorine or chlorine, or tetrahydropyran-2,5-diyl; ring E is 2,3-difluoro-1,4-phenylene, 2-chloro-3-fluoro-1,4-phenylene, 2,3-difluoro-5-methyl-1,4-phenylene, 3,4,5-trifluoronaphthalene-2,6-diyl or 7,8-difluorochroman-2,6-diyl; Z.sup.3 and Z.sup.4 are independently a single bond, ethylene, carbonyloxy or methyleneoxy; c is 1, 2 or 3, d is 0 or 1; and a sum of c and d is 3 or less.

8. The liquid crystal display device according to claim 7, wherein the third component is at least one compound selected from the group of compounds represented by formula (3-1) to formula (3-19): ##STR00138## ##STR00139## ##STR00140## in formula (3-1) to formula (3-19), R.sup.4 and R.sup.5 are independently alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbons, alkenyloxy having 2 to 12 carbons or alkyl having 1 to 12 carbons in which at least one hydrogen has been replaced by halogen.

9. The liquid crystal display device according to claim 7, wherein the ratio of the third component is in the range of 3% by weight to 30% by weight based on the weight of the liquid crystal composition.

10. The liquid crystal display device according to claim 1, wherein the operating mode of the liquid crystal display device is a TN mode, an ECB mode, an OCB mode, an IPS mode, an FFS mode, a PSA mode, or an FPA mode, and the driving mode of the liquid crystal display device is an active matrix mode.

11. The liquid crystal display device according to claim 1, wherein an elastic constant (K) of the liquid crystal composition at 25 C. is 13 pN or more.

12. The liquid crystal display device according to claim 1, wherein the flicker rate at 25 C. is in the range of 0% to 1%.

13. The liquid crystal display device according to claim 4, wherein the liquid crystal composition comprises at least one compound selected from the group of compounds represented by formula (3) as a third component: ##STR00141## in formula (3), R.sup.4 and R.sup.5 are independently alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbons, alkenyloxy having 2 to 12 carbons or alkyl having 1 to 12 carbons in which at least one hydrogen has been replaced by halogen; ring D and ring F are independently 1,4-cyclohexylene, 1,4-cyclohexenylene, 1,4-phenylene, 1,4-phenylene in which at least one hydrogen has been replaced by fluorine or chlorine, or tetrahydropyran-2,5-diyl; ring E is 2,3-difluoro-1,4-phenylene, 2-chloro-3-fluoro-1,4-phenylene, 2,3-difluoro-5-methyl-1,4-phenylene, 3,4,5-trifluoronaphthalene-2,6-diyl or 7,8-difluorochroman-2,6-diyl; Z.sup.3 and Z.sup.4 are independently a single bond, ethylene, carbonyloxy or methyleneoxy; c is 1, 2 or 3, d is 0 or 1; and a sum of c and d is 3 or less.

Description

EXAMPLES

(1) The invention will be explained in more detail byway of examples. The invention is not limited to the examples. The invention includes a mixture of the composition in Composition Example M1 and the composition in Composition Example M2. The invention also includes a mixture prepared by mixing at least two compositions in Composition Examples. Compounds prepared herein were identified by methods such as NMR analysis. The characteristics of the compounds, the compositions and the devices were measured by the methods described below.

(2) NMR Analysis

(3) A model DRX-500 apparatus made by Bruker BioSpin Corporation was used for measurement. In the measurement of .sup.1H-NMR, a sample was dissolved in a deuterated solvent such as CDCl.sub.3, and the measurement was carried out under the conditions of room temperature, 500 MHz and the accumulation of 16 scans. Tetramethylsilane (TMS) was used as an internal standard. In the measurement of .sup.19F-NMR, CFCl.sub.3 was used as the internal standard, and 24 scans were accumulated. In the explanation of the nuclear magnetic resonance spectra, the symbols s, d, t, q, quip, sex, m and br stand for a singlet, a doublet, a triplet, a quartet, a quintet, a sextet, a multiplet and line-broadening, respectively.

(4) Gas Chromatographic Analysis

(5) A gas chromatograph Model GC-14B made by Shimadzu Corporation was used for measurement. The carrier gas was helium (2 milliliters per minute). The sample injector and the detector (FID) were set to 280 C. and 300 C., respectively. A capillary column DB-1 (length 30 meters, bore 0.32 millimeter, film thickness 0.25 micrometer, dimethylpolysiloxane as the stationary phase, non-polar) made by Agilent Technologies, Inc. was used for the separation of component compounds. After the column had been kept at 200 C. for 2 minutes, it was further heated to 280 C. at the rate of 5 C. per minute. A sample was dissolved in acetone (0.1% by weight), and 1 microliter of the solution was injected into the sample injector. A recorder used was a Model C-R5A Chromatopac Integrator made by Shimadzu Corporation or its equivalent. The resulting gas chromatogram showed the retention time of peaks and the peak areas corresponding to the component compounds.

(6) Solvents for diluting the sample may also be chloroform, hexane and so forth. The following capillary columns may also be used in order to separate the component compounds: HP-1 made by Agilent Technologies Inc. (length 30 meters, bore 0.32 millimeter, film thickness 0.25 micrometer), Rtx-1 made by Restek Corporation (length 30 meters, bore 0.32 millimeter, film thickness 0.25 micrometer), and BP-1 made by SGE International Pty. Ltd. (length 30 meters, bore 0.32 millimeter, film thickness 0.25 micrometer). A capillary column CBP1-M50-025 (length 50 meters, bore 0.25 millimeter, film thickness 0.25 micrometer) made by Shimadzu Corporation may also be used for the purpose of avoiding an overlap of peaks of the compounds.

(7) The ratio of the liquid crystal compounds included in the composition may be calculated according to the following method. The liquid crystal compounds (a mixture) are detected by use of a gas chromatograph (FID). The ratio of peak areas in the gas chromatogram corresponds to the ratio (ratio by weight) of the liquid crystal compounds. When the capillary column described above is used, the correction coefficient of respective liquid crystal compounds may be regarded as 1 (one). Accordingly, the ratio (percentage by weight) of the liquid crystal compounds can be calculated from the ratio of peak areas.

(8) Samples for Measurement

(9) A composition itself was used as a sample when the characteristics of the composition or the device were measured. When the characteristics of a compound were measured, a sample for measurement was prepared by mixing this compound (15% by weight) with mother liquid crystals (85% by weight). The characteristic values of the compound were calculated from the values obtained from measurements by an extrapolation method: (Extrapolated value)=(Measured value of sample)0.85(Measured value of mother liquid crystals)/0.15. When a smectic phase (or crystals) deposited at 25 C. at this ratio, the ratio of the compound to the mother liquid crystals was changed in the order of (10% by weight: 90% by weight), (5% by weight: 95% by weight) and (1% by weight: 99% by weight). The values of the maximum temperature, the optical anisotropy, the viscosity and the dielectric anisotropy regarding the compound were obtained by means of this extrapolation method.

(10) The mother liquid crystals described below were used. The ratio of the component compounds were expressed as a percentage by weight.

(11) ##STR00110##
Measurement Methods

(12) The characteristics were measured according to the following methods. Most are methods described in the JEITA standards (JEITA-ED-25213) which was deliberated and established by Japan Electronics and Information Technology Industries Association (abbreviated to JEITA), or the modified methods. No thin film transistors (TFT) were attached to a TN device used for measurement.

(13) (1) Maximum Temperature of a Nematic Phase (NI; C.): A sample was placed on a hot plate in a melting point apparatus equipped with a polarizing microscope and was heated at the rate of 1 C. per minute. The temperature was measured when part of the sample began to change from a nematic phase to an isotropic liquid. A higher limit of the temperature range of a nematic phase may be abbreviated to the maximum temperature.
(2) Minimum Temperature of a Nematic Phase (Tc; C.): A sample having a nematic phase was placed in glass vials and then kept in freezers at temperatures of 0 C., 10 C., 20 C., 30 C. and 40 C. for 10 days, and then the liquid crystal phases were observed. For example, when the sample maintained the nematic phase at 20 C. and changed to crystals or a smectic phase at 30 C., Tc was expressed as <20 C. A lower limit of the temperature range of a nematic phase may be abbreviated to the minimum temperature.
(3) Viscosity (bulk viscosity; ; measured at 20 C.; mPa.Math.s): An E-type viscometer made by Tokyo Keiki Inc. was used for measurement.
(4) Viscosity (rotational viscosity; 1; measured at 25 C.; mPa.Math.s): The measurement was carried out according to the method described in M. Imai, et al., Molecular Crystals and Liquid Crystals, Vol. 259, 37 (1995). A sample was poured into a TN device in which the twist angle was 0 degrees and the distance between the two glass substrates (cell gap) was 5 micrometers. A voltage was applied to this device and increased stepwise with an increment of 0.5 volt in the range of 16 to 19.5 volts. After a period of 0.2 second with no voltage, a voltage was applied repeatedly under the conditions of a single rectangular wave alone (rectangular pulse; 0.2 second) and of no voltage (2 seconds). The peak current and the peak time of the transient current generated by the applied voltage were measured. The value of rotational viscosity was obtained from these measured values and the calculating equation (8) on page 40 of the paper presented by M. Imai, et al. The value of dielectric anisotropy necessary for this calculation was obtained by use of the device that had been used for the measurement of rotational viscosity, according to the method that will be described below.
(5) Optical anisotropy (refractive index anisotropy; n; measured at 25 C.): The measurement was carried out using an Abbe refractometer with a polarizing plate attached to the ocular, using light at a wavelength of 589 nanometers. The surface of the main prism was rubbed in one direction, and then a sample was placed on the main prism. The refractive index (n) was measured when the direction of the polarized light was parallel to that of rubbing. The refractive index (n) was measured when the direction of polarized light was perpendicular to that of rubbing. The value of the optical anisotropy (n) was calculated from the equation: n=nn.
(6) Dielectric anisotropy (; measured at 25 C.): A sample was poured into a TN device in which the distance between the two glass substrates (cell gap) was 9 micrometers and the twist angle was 80 degrees. Sine waves (10 V, 1 kHz) were applied to this device, and the dielectric constant () in the major axis direction of liquid crystal molecules was measured after 2 seconds. Sine waves (0.5 V, 1 kHz) were applied to this device and the dielectric constant () in the minor axis direction of the liquid crystal molecules was measured after 2 seconds. The value of dielectric anisotropy was calculated from the equation: =.
(7) Threshold voltage (Vth; measured at 25 C.; V): An LCD evaluation system Model LCD-5100 made by Otsuka Electronics Co., Ltd. was used for measurement. The light source was a halogen lamp. A sample was poured into a TN device having a normally white mode, in which the distance between the two glass substrates (cell gap) was 4.45/n (micrometers) and the twist angle was 80 degrees. A voltage to be applied to this device (32 Hz, rectangular waves) was stepwise increased in 0.02 V increments from 0 V up to 10 V. During the increase, the device was irradiated with light in the perpendicular direction, and the amount of light passing through the device was measured. A voltage-transmittance curve was prepared, in which the maximum amount of light corresponded to 100% transmittance and the minimum amount of light corresponded to 0% transmittance. The threshold voltage was expressed as a voltage at 90% transmittance.
(8) Voltage Holding Ratio (VHR-1; measured at 25 C.; %): A TN device used for measurement had a polyimide-alignment film, and the distance between the two glass substrates (cell gap) was 5 micrometers. A sample was poured into the device, and then this device was sealed with a UV-curable adhesive. A pulse voltage (60 microseconds at 5 V) was applied to this device and the device was charged. A decreasing voltage was measured for 16.7 milliseconds with a high-speed voltmeter, and area A between the voltage curve and the horizontal axis in a unit cycle was obtained. Area B was an area without the decrease. The voltage holding ratio was expressed as a percentage of area A to area B.
(9) Voltage Holding Ratio (VHR-2; measured at 80 C.; %): The voltage holding ratio was measured by the method described above, except that it was measured at 80 C. instead of 25 C. The resulting values were represented by the symbol VHR-2.
(10) Voltage Holding Ratio (VHR-3; measured at 25 C.; %): The stability to ultraviolet light was evaluated by measuring a voltage holding ratio after irradiation with ultraviolet light. A TN device used for measurement had a polyimide-alignment film and the cell gap was 5 micrometers. A sample was poured into this device, and then the device was irradiated with light for 20 minutes. The light source was an ultra-high-pressure mercury lamp USH-500D (produced by Ushio, Inc.), and the distance between the device and the light source was 20 centimeters. In the measurement of VHR-3, a decreasing voltage was measured for 16.7 milliseconds. A composition having a large VHR-3 has a high stability to ultraviolet light. The value of VHR-3 is preferably 90% or more, and more preferably 95% or more.
(11) Voltage Holding Ratio (VHR-4; measured at 25 C.; %): A TN device into which a sample was poured was heated in a constant-temperature bath at 80 C. for 500 hours, and then the stability to heat was evaluated by measuring the voltage holding ratio. In the measurement of VHR-4, a decreasing voltage was measured for 16.7 milliseconds. A composition having a large VHR-4 has a high stability to heat.
(12) Response Time (i; measured at 25 C.; millisecond): An LCD evaluation system Model LCD-5100 made by Otsuka Electronics Co., Ltd. was used for measurement. The light source was a halogen lamp. The low-pass filter was set at 5 kHz. A sample was poured into a FFS device assembled in Examples described below. This device was sealed with a UV-curable adhesive. Rectangular waves (60 Hz, 0.5 second) with a voltage where the amount of light passed through the device became maximum were applied to this device. The device was simultaneously irradiated with light in the perpendicular direction, and the amount of light passing through the device was measured. The transmittance was regarded as 100% when the amount of light reached a maximum. The transmittance was regarded as 0% when the amount of light reached a minimum. The response time was expressed as the period of time required for the change from 90% to 10% transmittance (fall time: millisecond). The response time is preferably 60 ms or less, and more preferably 40 ms or less.
(13) Elastic constants (K; measured at 25 C.; pN): A LCR meter Model HP 4284-A made by Yokokawa Hewlett-Packard, Ltd. was used for measurement. A sample was poured into a homogeneous device in which the distance between the two glass substrates (cell gap) was 20 micrometers. An electric charge of 0 volts to 20 volts was applied to this device, and the electrostatic capacity and the applied voltage were measured. The measured values of the electric capacity (C) and the applied voltage (V) were fitted to equation (2.98) and equation (2.101) on page 75 of Ekisho Debaisu Handobukku (Liquid Crystal Device Handbook, in English; The Nikkan Kogyo Shimbun, Ltd., Japan) and the values of K11 and K33 were obtained from equation (2.99). Next, the value of K22 was calculated from equation (3.18) on page 171 of the book and the values of K11 and K33 thus obtained. The elastic constant K was expressed as an average value of K11, K22 and K33.
(14) Specific Resistance (p; measured at 25 C.; Q cm): A sample of 1.0 milliliter was poured into a vessel equipped with electrodes. A DC voltage (10 V) was applied to the vessel, and the DC current was measured after 10 seconds. The specific resistance was calculated from the following equation: (specific resistance)=[(voltage)(electric capacity of vessel)]/[(DC current)(dielectric constant in vacuum)].
(15) Helical pitch (P; measured at room temperature; micrometer): The helical pitch was measured according to the wedge method (see page 196 of Ekishou Binran (Liquid Crystal Handbook, in English; Maruzen, Co., LTD., Japan, 2000). After a sample had been injected into a wedge-shaped cell and the cell had been allowed to stand at room temperature for 2 hours, the distance (d2d1) between disclination lines was observed with a polarizing microscope (Nikon Corporation, Model MM-40/60 series). The helical pitch (P) was calculated from the following equation, wherein was defined as the angle of the wedge cell: P=2(d2d1)tan .
(16) Dielectric constant in the minor axis direction (; measured at 25 C.): A sample was poured into a TN device in which the distance between the two glass substrates (cell gap) was 9 micrometers and the twist angle was 80 degrees. Sine waves (0.5 V, 1 kHz) were applied to this device and the dielectric constant () in the minor axis direction of the liquid crystal molecules was measured after 2 seconds.
(17) Flicker rate (measured at 25 C.; %): A multimedia display tester 3298F made by Yokogawa Electric Corporation was used for measurement. The light source was LED. A sample was poured into a FFS device assembled in Examples described below. This device was sealed with a UV-curable adhesive. A voltage was applied to the device and a voltage was measured when the amount of light passed through the device reached a maximum. The sensor was approximated to the device while this voltage was applied to the device, and the flicker rate displayed was recorded. The flicker rate is preferably 2% or less, and more preferably 1% or less.
(18) Weight average molecular weight (Mw): The weight average molecular weight of a polyamic acid was measured by a GPC method using 2695 separation module 2414 differential refractometer made by Waters Corporation, and was expressed in terms of polystyrene equivalents. The resulting polyamic acid was diluted with a phosphoric acid-DMF mixed solution (phosphoric acid/DMF=0.6/100, in weight ratio), giving about approximately 2% by weight concentration of the polyamic acid. A column used was HSPgel RT MB-M made by Waters Corporation, and the measurement was carried out under the conditions of 50 C. of the column temperature and 0.40 mL/min of the current velocity using the mixed solution as an eluent A TSK standard polystyrene made by Tosoh Corporation was used as the standard polystyrene.
(19) Pretilt angle: A spectroscopic ellipsometer M-2000U made by J. A. Woollam Co. Inc. was used for the measurement of pretilt angles.
(20) AC ghost images (Brightness change): In the liquid crystal display device that will be described below, the brightness-voltage characteristics (B-V characteristics) were measured. This was referred to as brightness-voltage characteristics before stressed [B (before)]. Next, direct current (4.5 V, 60 Hz) was applied for 20 minutes to the device, and no voltages for 1 second, and then the brightness-voltage characteristics (B-V characteristics) were measured again. This was referred to as brightness-voltage characteristics after stressed [B (after)]. The brightness change (B; %) was calculated from these values by the following equation:
B (%)=[B(after)B(before)]/B(before)(equation 1)
These measurements were carried out by referring WO 2000-43833 A. The smaller value of B (%) at a voltage of 0.75 V means a smaller generation of AC ghost images.
(21) Orientational stability (Stability of liquid crystal orientational axis): In the liquid crystal display device that will be described below, the change of a liquid crystal orientational axis in a side of electrode was evaluated. Liquid crystal orientation angle [ (before)] before stressed in the side of an electrode was measured, and rectangular waves (4.5 V, 60 Hz) were applied for 20 minutes to the device, and no voltages for 1 second, and then the liquid crystal orientation angle [( (after)] in the side of the electrode was measured after 1 second and 5 minutes. The change (, deg.) of the liquid crystal orientation angle after 1 second and 5 minutes was calculated from these values by the following equation:
(deg.)=(after)(before)(equation 2)
These measurements was carried out by referring J. Hilfiker, B. Johs, C. Herzinger, J. F. Elman, E. Montbach, D. Bryant and P. J. Bos, Thin Solid Films, 455-456, (2004) 596-600. The smaller value of means a smaller change ratio of the liquid crystal orientational axis, which means that the stability of liquid crystal orientational axis is better.
(22) Volume resistivity (; measured at 25 C.; .Math.cm): A polyimide film was formed on a glass substrate covered with ITO entirely. Aluminum was deposited to the side of the alignment film on the substrate, which was referred to as an upper electrode (electrode surface area: 0.23 cm.sup.2). A voltage of 3 V was applied between the ITO electrode and the upper electrode, and the volume resistivity was calculated from a current value after 300 seconds.
(23) Permittivity (; measured at 25 C.): A polyimide film was prepared on a substrate covered with ITO entirely. Aluminum was deposited to the side of the alignment film on the substrate, which was referred to as an upper electrode (electrode surface area: 0.23 cm.sup.2). A voltage of 3 V was applied between the ITO electrode and the upper electrode, and an AC voltage (1 V, frequency 1 kHz) was applied, and the electric capacity (C) of the film was measured. The permittivity (s) of the film was calculated from this value by the following equation:
=(Cd)/(.sub.0S)(equation 3)
where d is the film thickness of the polyimide film, .sub.0 is permittivity in vacuum, and S is the electrode surface.
(24) Abbreviations: Abbreviations of solvents and additives used in Examples are as follows.
Solvent
NMP: N-Methyl-2-pyrrolidone.
BC: Butyl cellosolve (ethylene glycol monobutyl ether).
Additive
Additive (Ad1): Bis[4-(allylbicyclo[2.2.1]hept-5-ene-2,3-dicarboximide)phenyl]methane.
Additive (Ad2): N,N,N,N-Tetraglycidyl-4,4-diaminodiphenylmethane.
Additive (Ad3): 3-Aminopropyltriethoxysilane.
Additive (Ad4): 2-(3,4-Epoxycyclohexyl)ethyltrimethoxysilane.

(14) The compounds described in Examples were expressed in terms of symbols according to the definition in Table 3 described below. In Table 3, the configuration of 1,4-cyclohexylene is trans. The parenthesized number next to a symbolized compound in Example corresponds to the number of the compound. The symbol (-) means any other liquid crystal compound. The ratio (percentage) of a liquid crystal compound means the percentages by weight (% by weight) based on the liquid crystal composition. Last, the values of characteristics of the composition are summarized.

(15) TABLE-US-00003 TABLE 3 Method of Description of Compounds R(A.sub.1)Z.sub.1- . . . Z.sub.n(A.sub.n)R 1) Left-terminal Group R Symbol C.sub.nH.sub.2n+1 n- C.sub.nH.sub.2n+1O nO C.sub.mH.sub.2m+1OC.sub.nH.sub.2n mOn- CH.sub.2CH V C.sub.nH.sub.2n+1CHCH nV CH.sub.2CHC.sub.nH.sub.2n Vn- C.sub.mH.sub.2m+1CHCHC.sub.nH.sub.2n mVn- CF.sub.2CH VFF CF.sub.2CHC.sub.nH.sub.2n VFFn- FC.sub.nH.sub.2n Fn- 2) Right-terminal Group R Symbol C.sub.nH.sub.2n+1 -n OC.sub.nH.sub.2n+1 On CHCH.sub.2 V CHCHC.sub.nC.sub.2n+1 Vn C.sub.nH.sub.2nCHCH.sub.2 -nV C.sub.nH.sub.2nCHCHC.sub.mH.sub.2m+1 -nVm CHCF.sub.2 VFF COOCH.sub.3 -EMe F F Cl CL OCF.sub.3 OCF3 CF.sub.3 CF3 CN C 3) Bonding Group Z.sub.n Symbol C.sub.2H.sub.4 2 COO E CHCH V CC T CF.sub.2O X CH.sub.2O 1O 4) Ring A.sub.n Symbol H Dh dh B B(F) B(2F) B(F,F) B(2F,5F) G 0 Py B(2F,3F) Examples of Description Example 1. VHHB-1 Example 2. 3-BB(F)B(F,F)F Example 3. 4-BB(F)B(F,F)XB(F,F)F Example 4. 5-GB(F,F)XB(F,F)F

Composition Example M1

(16) TABLE-US-00004 3-HHXB(F,F)-F (1-4) 13% 3-BBXB(F,F)-F (1-17) 4% 3-BB(F,F)XB(F,F)-F (1-18) 10% 3-HBBXB(F,F)-F (1-23) 6% 3-HBB(F,F)XB(F,F)-F (1-24) 6% 3-GB(F)B(F,F)XB(F,F)-F (1-27) 3% 4-GB(F)B(F,F)XB(F,F)-F (1-27) 3% 3-HH-V (2-1) 32% 3-HH-V1 (2-1) 7% V-HHB-1 (2-5) 6% V2-HHB-1 (2-5) 6% 1-BB(F)B-2V (2-7) 4%
NI=84.5 C.; Tc<30 C.; n=0.101; =7.6; Vth=1.56 V; =12.1 mPa.Math.s; VHR-1=99.1%; VHR-2=98.2%; VHR-3=98.1%.

Composition Example M2

(17) TABLE-US-00005 3-HHXB(F,F)-CF3 (1-5) 4% 3-GB(F,F)XB(F,F)-F (1-14) 5% 3-BB(F)B(F,F)-F (1-15) 9% 3-BB(F,F)XB(F,F)-F (1-18) 17% 3-HBBXB(F,F)-F (1-23) 7% 3-GB(F)B(F,F)XB(F,F)-F (1-27) 2% 3-BB(F)B(F,F)XB(F,F)-F (1-28) 2% 4-BB(F)B(F,F)XB(F,F)-F (1-28) 6% 5-BB(F)B(F,F)XB(F,F)-F (1-28) 6% 3-HH-V (2-1) 21% V-HHB-1 (2-5) 9% V2-HHB-1 (2-5) 9% 1-BB(F)B-2V (2-7) 3%
NI=79.5 C.; Tc<30 C.; n=0.129; =15.9; Vth=1.25 V; =21.2 mPa.Math.s.

Composition Example M3

(18) TABLE-US-00006 3-HB(F)B(F,F)-F (1-9) 5% 3-GB(F)B(F,F)-F (1-12) 6% 3-BB(F,F)XB(F,F)-F (1-18) 2% 4-GB(F)B(F,F)XB(F,F)-F (1-27) 3% 4-BB(F)B(F,F)XB(F,F)-F (1-28) 6% 3-HH-V (2-1) 31% 3-HH-V1 (2-1) 6% 1-HH-2V1 (2-1) 6% V-HHB-1 (2-5) 14% V2-HHB-1 (2-5) 12% 3-HHB-1 (2-5) 3% 3-HHB-O1 (2-5) 3% 2-BB(F)B-3 (2-7) 3%
NI=92.1 C.; Tc<20 C.; n=0.095; =4.1; Vth=2.05 V; =13.3 mPa.Math.s.

Composition Example M4

(19) TABLE-US-00007 3-GB(F,F)XB(F)-F (1-13) 4% 3-BB(F,F)XB(F,F)-F (1-18) 18% 3-GB(F)B(F,F)XB(F,F)-F (1-27) 5% 4-GB(F)B(F,F)XB(F,F)-F (1-27) 3% 5-GB(F)B(F,F)XB(F,F)-F (1-27) 3% 3-BB(F,F)XB(F)B(F,F)-F (1-29) 5% 3-HH-V (2-1) 24% 3-HH-V1 (2-1) 8% V-HHB-1 (2-5) 10% V2-HHB-1 (2-5) 10% 3-HHB-1 (2-5) 4% 3-HBB-2 (2-6) 6%
NI=81.8 C.; Tc<20 C.; n=0.105; =9.2; Vth=1.46 V; =15.6 mPa.Math.s.

Composition Example M5

(20) TABLE-US-00008 3-HHB(F,F)-F (1-2) 5% 3-GHB(F,F)-F (1-7) 10% 3-HBB(F,F)-F (1-8) 10% 3-HHBB(F,F)-F (1-19) 6% 3-HBB(F,F)XB(F,F)-F (1-24) 4% 4-GB(F)B(F,F)XB(F)-F (1-26) 3% 4-GB(F)B(F,F)XB(F,F)-F (1-27) 3% 3-HH-V (2-1) 34% 3-HH-V1 (2-1) 7% V-HHB-1 (2-5) 7% 3-BB(F)B-5 (2-7) 2% 3-HHEBH-3 (2-10) 5% 5-HBB(F)B-2 (2-13) 4%
NI=97.9 C.; Tc<20 C.; n=0.100; =6.8; Vth=1.80 V; =21.5 mPa.Math.s.

Composition Example M6

(21) TABLE-US-00009 3-HHEB(F,F)-F (1-3) 3% 3-GB(F)B(F,F)-F (1-12) 10% 4-GB(F)B(F,F)XB(F,F)-F (1-27) 3% 4-BB(F)B(F,F)XB(F,F)-F (1-28) 6% 3-B(2F,3F)BXB(F,F)-F (1-32) 3% 3-HB(2F,3F)BXB(F,F)-F (1-33) 3% 3-HHB-F (1) 5% 3-HH-V1 (2-1) 6% 5-HH-V (2-1) 14% 3-HH-2V1 (2-1) 6% 3-HH-4 (2-1) 11% 7-HB-1 (2-2) 3% 5-HB-O2 (2-2) 5% 3-HHEH-3 (2-4) 3% V-HHB-1 (2-5) 6% V2-HHB-1 (2-5) 9% 2-BB(F)B-3 (2-7) 4%
NI=90.0 C.; Tc<30 C.; n=0.098; =6.0; Vth=1.89 V; =18.6 mPa.Math.s.

Composition Example M7

(22) TABLE-US-00010 3-GB(F,F)XB(F,F)-F (1-14) 8% 3-BB(F,F)XB(F,F)-F (1-18) 5% 3-HBBXB(F,F)-F (1-23) 6% 3-HBB(F,F)XB(F,F)-F (1-24) 7% 3-BB(F,F)XB(F)-OCF3 (1) 5% 3-HH-V (2-1) 12% 4-HH-V (2-1) 8% F3-HH-V (2-1) 11% V-HHB-1 (2-5) 7% 3-HHB-3 (2-5) 4% V-HBB-2 (2-6) 7% V2-BB(F)B-1 (2-7) 3% 2-BB(2F,3F)B-3 (3-9) 12% 3-HBB(2F,3F)-O2 (3-13) 5%
NI=84.9 C.; Tc<30 C.; n=0.125; =5.6; Vth=1.82 V; =13.8 mPa.Math.s.

Composition Example M8

(23) TABLE-US-00011 3-HHXB(F,F)-F (1-4) 9% 3-BB(F,F)XB(F,F)-F (1-18) 16% 3-dhBB(F,F)XB(F,F)-F (1-25) 8% 3-BB(F)B(F,F)XB(F,F)-F (1-28) 5% 3-HH-V (2-1) 22% 3-HH-V1 (2-1) 10% 1-BB-5 (2-3) 8% 3-HHB-O1 (2-5) 5% 3-HBB-2 (2-6) 5% 1V-HBB-2 (2-6) 5% 3-HB(F)BH-3 (2-12) 4% 5-HB(F)BH-3 (2-12) 3%
NI=70.0 C.; Tc<20 C.; n=0.096; =7.3; Vth=1.52 V; =11.4 mPa.Math.s.

Composition Example M9

(24) TABLE-US-00012 3-BB(F)B(F,F)-F (1-15) 6% 3-BB(F)B(F,F)-CF3 (1-16) 3% 3-BB(F,F)XB(F,F)-F (1-18) 4% 3-HBBXB(F,F)-F (1-23) 5% 4-GB(F)B(F,F)XB(F,F)-F (1-27) 4% 4-BB(F)B(F,F)XB(F,F)-F (1-28) 7% 3-BB(2F,3F)BXB(F,F)-F (1-34) 2% 3-HH-V (2-1) 30% 3-HH-V1 (2-1) 6% 3-HH-VFF (2-1) 8% 3-HB-O2 (2-2) 3% V-HHB-1 (2-5) 5% 1-BB(F)B-2V (2-7) 4% 2-BB(F)B-2V (2-7) 4% 3-HB(2F,3F)-O2 (3-1) 3% 3-BB(2F,3F)-O2 (3-4) 3% 3-HHB(2F,3F)-O2 (3-6) 3%
NI=75.2 C.; Tc<20 C.; n=0.111; =5.4; Vth=1.85 V; =12.2 mPa.Math.s.

Composition Example M10

(25) TABLE-US-00013 3-HGB(F,F)-F (1-6) 6% 4-GB(F)B(F,F)XB(F,F)-F (1-27) 3% 3-BB(F)B(F,F)XB(F,F)-F (1-28) 2% 4-BB(F)B(F,F)XB(F,F)-F (1-28) 5% 5-BB(F)B(F,F)XB(F,F)-F (1-28) 6% 3-HHB-CL (1) 3% 3-HH-V (2-1) 30% 2-HH-3 (2-1) 7% V-HHB-1 (2-5) 15% V2-HHB-1 (2-5) 8% 3-HHEBH-4 (2-10) 3% 5-HBB(F)B-2 (2-13) 7% 5-HBB(F)B-3 (2-13) 5%
NI=117.6 C.; Tc<30 C.; n=0.115; =4.2; Vth=2.45 V; =14.5 mPa.Math.s.

Composition Example M11

(26) TABLE-US-00014 3-BB(F)B(F,F)-F (1-15) 21% 2O-B(2F,3F)BXB(F,F)-F (1-32) 4% 3-HB-CL (1) 5% 3-HH-V (2-1) 25% 4-HH-V1 (2-1) 3% V2-BB-1 (2-3) 5% 1V2-BB-1 (2-3) 5% 1-BB(F)B-2V (2-7) 8% 2-BB(F)B-2V (2-7) 8% 3-BB(F)B-2V (2-7) 8% 5-B(F)BB-2 (2-8) 4% 5-HBBH-1O1 () 4%
NI=78.2 C.; Tc<10 C.; n=0.166; =3.8; Vth=2.47 V; =25.5 mPa.Math.s.

Composition Example M12

(27) TABLE-US-00015 3-HHXB(F,F)-F (1-4) 2% 3-GB(F)B(F)-F (1-11) 8% 3-GB(F)B(F)B(F)-F (1-21) 2% 4-GBB(F)B(F,F)-F (1-22) 3% 3-BB(2F,3F)XB(F,F)-F (1-31) 9% 3-HHB(F)-F (1) 3% 3-HBB(F)-F (1) 3% 3-HH-V (2-1) 30% F3-HH-V (2-1) 8% 3-HB-O2 (2-2) 5% V-HBB-2 (2-6) 6% 1-BB(F)B-2V (2-7) 4% 2-BB(F)B-2V (2-7) 6% 3-BB(F)B-2V (2-7) 5% 5-HBBH-3 (2-11) 3% 3-dhBB(2F,3F)-O2 (3-14) 3%
NI=82.2 C.; Tc<30 C.; n=0.124; =3.1; Vth=2.41 V; =16.4 mPa.Math.s.

Composition Example M13

(28) TABLE-US-00016 5-HXB(F,F)-F (1-1) 3% 4-BB(F)B(F,F)XB(F,F)-F (1-28) 9% 3-BB(F)B(F,F)XB(F)B(F,F)-F (1-30) 3% 3-HHXB(F,F)-OCF3 (1) 7% 3-HH2B(F,F)-F (1) 4% 3-HH-V (2-1) 44% 3-HH-V1 (2-1) 5% V-HHB-1 (2-5) 7% V2-HHB-1 (2-5) 5% 3-HHB-1 (2-5) 3% 2-BB(F)B-2V (2-7) 3% 3-BB(F)B-2V (2-7) 3% 3-HB(F)HH-5 (2-9) 4%
NI=99.7 C.; Tc<20 C.; n=0.100; =3.9; Vth=2.25 V; =10.3 mPa.Math.s.

Composition Example M14

(29) TABLE-US-00017 3-HBEB(F,F)-F (1-10) 5% 3-HBBXB(F,F)-F (1-23) 10% 3-BB(F)B(F,F)XB(F,F)-F (1-28) 2% 4-BB(F)B(F,F)XB(F,F)-F (1-28) 7% 3-HBB-F (1) 3% 3-dhB(F,F)XB(F,F)-F (1) 8% 3-HH-V (2-1) 35% 1-HH-2V1 (2-1) 5% 3-HH-2V1 (2-1) 4% 3-HH-O1 (2-1) 5% V-HHB-1 (2-5) 8% 3-HHB-1 (2-5) 4% 3-HB(F)BH-3 (2-12) 4%
NI=85.6 C.; Tc<30 C.; n=0.096; =5.5; Vth=1.75 V; =13.7 mPa.Math.s.
1. Preparation of Polyamic Acid Solutions (Component [A])

Synthetic Example 1

(30) In a brown four-neck flask 50 mL equipped with a thermometer, a stirrer, an inlet for a starting materials and a nitrogen gas inlet, 0.2102 g of diamine (DI-5-1, m=2), 0.0664 g of diamine (DI-9-1), 0.2082 g of diamine (PDI-6-1), 0.5778 g of diamine (PDI-7-1) and 18.5 g of dry NMP were placed, and stirred to dissolve under a stream of dry-nitrogen. Then, 0.1268 g of acid dianhydride (AN-1-13), 1.8106 g of acid dianhydride (AN-4-17, j=8) and 18.5 g of dry NMP were added and the mixture was stirred at room temperature for 24 hours. 10.0 g of BC was added to this reaction mixture to give a polyamic acid solution with a polymer solid content of 6% by weight. The polyamic acid solution was referred to as PA1. The weight-average molecular weight of the polyamic acid included in PA1 was 39,400.

Synthetic Examples 2 to 8

(31) Polyamic acid solutions (PA2) to (PA8) with a polymer solid content of 6% by weight were prepared according to Synthetic Example 1 except that the type of tetracarboxylic acid dianhydrides and diamines were changed. Polyamic acid solutions (PA1) to (PA8) were referred to as component [A]. Table 4 summarizes the results.

(32) TABLE-US-00018 TABLE 4 Preparation of polyamic acid solutions (PA1) to (PA8) Synthetic Polyamic Tetracarboxylic acid Weight average Example acid dianhydride Diamine molecular No. No. (mol %) (mol %) weight 1 PA1 AN-1-13 (10) DI-5-1(m = 2) (20) 39,400 AN-4-17(j = 8) (90) DI-9-1 (5) PDI-6-1 (20) PDI-7-1 (55) 2 PA2 AN-3-1 (30) DI-5-1(m = 2) (50) 42,000 AN-4-17(j = 8) (70) PDI-7-1 (50) 3 PA3 AN-4-17(j = 8) (100) DI-5-1(m = 4) (40) 32,000 PDI-7-1 (60) 4 PA4 AN-4-21 (100) DI-5-1(m = 4) (25) 21,700 PDI-7-1 (75) 5 PA5 AN-4-21 (100) DI-5-4 (50) 28,600 PDI-7-1 (50) 6 PA6 PAN-2 (100) DI-2-1 (20) 40,700 PDI-7-1 (80) 7 PA7 AN-4-17(j = 8) (100) DI-19-7(R.sup.33 = C.sub.7H.sub.15) (3) 17,500 PDI-7-1 (97) 8 PA8 AN-4-17(j = 8) (100) DI-4-13 (10) 15,200 DI-16-5(R.sup.27 = C.sub.5H.sub.11) (5) PDI-7-1 (85)
2. Preparation of Polyamic Acid Solutions (Component [B])

Synthetic Example 9

(33) In a 50 mL brown four-neck flask equipped with a thermometer, a stirrer, an inlet for a starting materials and a nitrogen gas inlet, 0.7349 g of diamine (DI-4-1) and 18.5 g of dry NMP were placed, and stirred to dissolve under a stream of dry-nitrogen. Then, 0.6732 g of acid dianhydride (AN-1-1), 1.5918 g of acid dianhydride (AN-4-28) and 18.5 g of dry NMP were placed and the mixture was stirred at room temperature for 24 hours. 10.0 g of BC was added to this reaction mixture to give a polyamic acid solution with a polymer solid content of 6% by weight. The polyamic acid solution was referred to as PA9. The weight-average molecular weight of the polyamic acid included in PA9 was 51,500.

Synthetic Examples 10 to 24

(34) Polyamic acid solutions (PA10) to (PA24) with a polymer solid content of 6% by weight were prepared according to Synthetic Example 9 except that the type of tetracarboxylic acid dianhydrides and diamines were changed. Polyamic acid solutions (PA9) to (PA24) were referred to as component [B]. Table 5 summarizes the results.

(35) TABLE-US-00019 TABLE 5 Preparation of polyamic acid solutions (PA9) to (PA24) Synthetic Polyamic Tetracarboxylic Weight average Example acid acid dianhydride Diamine molecular No. No. (mol %) (mol %) weight 9 PA9 AN-1-1 (50) DI-4-1 (100) 51,000 AN-4-28 (50) 10 PA10 AN-1-1 (5) DI-5-1(m = 1) (90) 79,200 AN-2-1 (95) DI-5-4 (10) 11 PA11 AN-1-1 (5) DI-5-1(m = 8) (100) 72,200 AN-2-1 (95) 12 PA12 AN-1-13 (40) DI-5-1(m = 4) (100) 84,000 AN-3-2 (60) 13 PA13 AN-1-13 (40) DI-5-1(m = 4) (80) 71,100 AN-3-2 (40) DI-14-1 (20) AN-4-28 (20) 14 PA14 AN-1-13 (20) D-14-1 (100) 100,600 AN-4-28 (80) 15 PA15 AN-2-1 (100) DI-2-1 (50) 90,200 DI-9-1 (50) 16 PA16 AN-2-1 (100) DI-4-1 (100) 86,400 17 PA17 AN-2-1 (100) DI-5-1(m = 1) (80) 90,800 DI-9-1 (20) 18 PA18 AN-2-1 (80) DI-5-1(m = 1) (100) 69,900 AN-3-1 (20) 19 PA19 AN-2-1 (70) DI-5-1(m = 1) (80) 74,000 AN-3-2 (30) DI-9-1 (20) 20 PA20 AN-2-1 (100) DI-5-1(m = 2) (80) 90,500 DI-5-30 (20) 21 PA21 AN-3-1 (10) DI-4-1 (100) 68,600 AN-3-2 (50) AN-4-28 (40) 22 PA22 AN-3-1 (100) DI-1-3 (100) 101,000 23 PA23 AN-4-5 (100) DI-1-3 (100) 75,200 24 PA24 AN-2-1 (50) DI-4-1 (100) 76,000 AN-3-2 (50)

(36) Polyamic acid (PA1) prepared in Synthetic Example 1 as component [A] and polyamic acid (PA9) prepared in Synthetic Example 9 as component [B] were mixed in a weight ratio of [A]/[B]=3.0/7.0, which was referred to as PA25.

(37) Polyamic acid solutions (PA26) to (PA43) with a polymer solid content of 6% by weight were prepared by changing the type of component [A] and component [B], and the mixing ratio of [A]/[B]. Table 6 summarizes the results.

(38) TABLE-US-00020 TABLE 6 Polyamic acid solutions (PA25) to (PA43) Component [A] Component [B] Mixing ratio of Polyamic acid Polyamic acid Polyamic acid [A]/[B] No. No. No. (weight ratio) PA25 PA1 PA9 3.0/7.0 PA26 PA2 PA10 3.0/7.0 PA27 PA2 PA11 3.0/7.0 PA28 PA2 PA12 3.0/7.0 PA29 PA3 PA13 3.0/7.0 PA30 PA3 PA14 2.0/8.0 PA31 PA4 PA15 2.0/8.0 PA32 PA4 PA16 2.0/8.0 PA33 PA5 PA17 3.0/7.0 PA34 PA5 PA18 3.0/7.0 PA35 PA6 PA19 3.0/7.0 PA36 PA3 PA20 3.0/7.0 PA37 PA3 PA21 3.0/7.0 PA38 PA4 PA22 2.5/7.5 PA39 PA4 PA23 2.5/7.5 PA40 PA7 PA12 3.0/7.0 PA41 PA7 PA24 3.0/7.0 PA42 PA8 PA19 3.0/7.0 PA43 PA8 PA24 3.0/7.0

(39) Additive (Ad1) was added to polyamic acid solution (PA3) with a polymer solid content of 6% by weight prepared in Synthetic Example 3, in a ratio of 5% by weight based on the polymer solid content. The resulting polyamic acid solution was referred to as PA44. Additives (Ad2) to (Ad4) were added to polyamic acid solutions to prepared polyamic acid solutions (PA45) to (PA48). Table 7 summarizes the results. Incidentaly, abbreviations such as Ad1 was explained in item (24).

(40) TABLE-US-00021 TABLE 7 Polyamic acid solutions (PA44) to (PA48) including an additive Polyamic acid Polyamic acid Added amount No. solution Additive (% by weight) PA44 PA3 Ad1 5 PA45 PA30 Ad2 5 PA46 PA35 Ad3 4 PA47 PA37 Ad4 3 PA48 PA41 Ad4 0.5
3. Production of the Liquid Crystal Display Device

Example 1

(41) Formation of the Alignment Film

(42) A mixed solvent of NMP/BC=4/1 (ratio by weight) was added to polyamic acid solution (PA1) with a polymer solid content of 6% by weight prepared in Synthetic Example 1 to give a liquid crystal aligning agent with a polymer solid content of 4% by weight. The liquid crystal aligning agent was applied to a glass substrate with column spacer and a glass substrate with an ITO electrode, with a spinner (a spin coater 1H-DX2 made by Mikasa Co., Ltd). Incidentally, the film thickness described below was adjusted by changing the rotating rate of the spinner according to the viscosity of liquid crystal aligning agents, which was applied to the following Examples and Comparative Examples. The coating film was heated and dried at 70 C. for 80 seconds on a hot-plate (an EC hot-plate EC-1200N made by As One Corporation). Then, the film was irradiated with linearly polarized ultraviolet light via a polarizing plate in the direction perpendicular to the substrate using Multilight ML-501C/B made by Ushio, Inc. The amount of light was measured with an accumulated UV meter UIT-150 (receiver UVD-S365) made by Ushio, Inc. and the exposure energy was adjusted to be 2.00.1 J/cm.sup.2 at a wavelength of 365 nm by changing the exposure time. Then, the film was heated for 15 minutes at 230 C. in a clean oven (a clean oven PVHC-231 made by Espec Corporation) to form an alignment film with film thickness of 10010 nm.

(43) Production of the Device

(44) An FFS device was assembled in which two substrates were pasted together, the surfaces of the alignment films were inside, and the directions of linearly polarized ultraviolet light were parallel, and the distance between the substrates was 4 micrometers. An injection inlet for liquid crystals was arranged to the position where the flow direction of liquid crystals was roughly parallel to the linearly polarized ultraviolet light. The liquid crystal composition in Composition Example M1 was injected in vacuum to this FFS device, and the response time and the flicker rate were measured. Table 8 summarizes the results.

Examples 2 to 21

(45) A mixed solvent of NMP/BC=4/1 (ratio by weight) was added to each of polyamic acid solutions (PA2), (PA25) to (PA39) and (PA44) to (PA47) with a polymer solid content of 6% by weight to give a liquid crystal aligning agent with a polymer solid content of 4% by weight. A FFS liquid crystal display device was produced according to Example 1 using the resulting liquid crystal aligning agent. The liquid crystal composition prepared in Composition Example M2 to M13 was injected to the device, and the response time and the flicker rate were measured. Table 8 summarizes the results.

Example 22

(46) Formation of the Alignment Film

(47) A mixed solvent of NMP/BC=4/1 (ratio by weight) was added to polyamic acid solution (PA27) with a polymer solid content of 6% by weight to give a liquid crystal aligning agent with a polymer solid content of 4% by weight. The liquid crystal aligning agent was applied to a glass substrate with column spacer and a glass substrate with an ITO electrode, with a spinner (a spin coater 1H-DX2 made by Mikasa Co., Ltd). The coating film was heated and dried at 70 C. for 80 seconds on a hot-plate (an EC hot-plate EC-1200N made by As One Corporation). The film was irradiated with linearly polarized ultraviolet light via a polarizing plate in the direction perpendicular to the substrate using Multilight ML-501C/B made by Ushio, Inc. The amount of light was measured with an accumulated UV meter UIT-150 (receiver UVD-S365) made by Ushio, Inc. and the exposure energy was adjusted to be 2.00.1 J/cm.sup.2 at a wavelength of 365 nm by changing the exposure time. During the exposure to ultraviolet light, the substrate was heated at 50 C. Irradiation with ultraviolet light was carried out at room temperature under air, and the whole apparatus was covered with an ultraviolet protection film. Then, the film was heated for 15 minutes at 230 C. in a clean oven (a clean oven PVHC-231 made by Espec Corporation) to form an alignment film with film thickness of 10010 nm.

(48) Production of the Device

(49) An FFS device was assembled in which two substrates were pasted together, the surfaces of the alignment films were inside, and the directions of linearly polarized ultraviolet light were parallel, and the distance between the substrates was 4 micrometers. An injection inlet for liquid crystals was arranged to the position where the flow direction of liquid crystals was roughly parallel to the linearly polarized ultraviolet light. The liquid crystal composition in Composition Example M9 was injected in vacuum to this FFS device, and the response time and the flicker rate were measured. Table 8 summarizes the results.

Example 23 to 25

(50) A mixed solvent of NMP/BC=4/1 (ratio by weight) was added to polyamic acid solutions (PA40), (PA42) and (PA48) with a polymer solid content of 6% by weight to give a liquid crystal aligning agent with a polymer solid content of 4% by weight. A liquid crystal display device was produced according to Example 22 using the resulting liquid crystal aligning agent. The liquid crystal composition prepared in Composition Example M10 to M13 was injected to the device, and the response time and the flicker rate were measured. Table 8 summarizes the results.

Example 26

(51) Formation of the Alignment Film

(52) A mixed solvent of NMP/BC=4/1 (ratio by weight) was added to polyamic acid solution (PA34) with a polymer solid content of 6% by weight to give a liquid crystal aligning agent with a polymer solid content of 4% by weight. The liquid crystal aligning agent was applied to a glass substrate with column spacer and a glass substrate with an ITO electrode, with a spinner (a spin coater 1H-DX2 made by Mikasa Co., Ltd). The coating film was heated and dried at 70 C. for 80 seconds on a hot-plate (an EC hot-plate EC-1200N made by As One Corporation). The film was irradiated with linearly polarized ultraviolet light via a polarizing plate in the direction perpendicular to the substrate using a UV lamp (UVL-1500 M2-N1) made by Ushio, Inc. The amount of light was measured with an accumulated UV meter UIT-150 (receiver UVD-S365) made by Ushio, Inc. and the exposure energy was adjusted to be 1.00.1 J/cm.sup.2 at a wavelength of 365 nm by changing the exposure time. Irradiation with ultraviolet light was carried out at room temperature under air, and the whole apparatus was covered with an ultraviolet protection film. Then, the film was heated for 15 minutes at 230 C. in a clean oven (a clean oven PVHC-231 made by Espec Corporation) to form an alignment film with film thickness of 10010 nm.

(53) Production of the Device

(54) An FFS device was assembled in which two substrates were pasted together, the surfaces of the alignment films were inside, and the directions of linearly polarized ultraviolet light were parallel, and the distance between the substrates was 4 micrometers. An injection inlet for liquid crystals was arranged to the position where the flow direction of liquid crystals was roughly parallel to the linearly polarized ultraviolet light. The liquid crystal composition in Composition Example M13 was injected in vacuum to this FFS device, and the response time and the flicker rate were measured. Table 8 summarizes the results.

Examples 27 and 28

(55) A mixed solvent of NMP/BC=4/1 (ratio by weight) was added to polyamic acid solutions (PA41) and (PA43) with a polymer solid content of 6% by weight to give a liquid crystal aligning agent with a polymer solid content of 4% by weight. A liquid crystal display device was produced according to Example 26 using the resulting liquid crystal aligning agent. The liquid crystal composition prepared in Composition Example M10 to M13 was injected to the device, and the response time and the flicker rate were measured. Table 8 summarizes the results.

Example 29

(56) Formation of the Alignment Film

(57) A mixed solvent of NMP/BC=4/1 (ratio by weight) was added to polyamic acid solution (PA33) with a polymer solid content of 6% by weight to give a liquid crystal aligning agent with a polymer solid content of 4% by weight. The liquid crystal aligning agent was applied to a glass substrate with column spacer and a glass substrate with an ITO electrode, with a spinner (a spin coater 1H-DX2 made by Mikasa Co., Ltd). The coating film was heated and dried at 70 C. for 80 seconds on a hot-plate (an EC hot-plate EC-1200N made by As One Corporation). Then, the film was irradiated with linearly polarized ultraviolet light via a polarizing plate in the direction perpendicular to the substrate using Multilight ML-501C/B made by Ushio, Inc. The amount of light was measured with an accumulated UV meter UIT-150 (receiver UVD-S365) made by Ushio, Inc. and the exposure energy was adjusted to be 2.00.1 J/cm.sup.2 at a wavelength of 365 nm by changing the exposure time. Then, the film was heated for 15 minutes at 230 C. in a clean oven (a clean oven PVHC-231 made by Espec Corporation) to form an alignment film with film thickness of 10010 nm.

(58) Production of the Device

(59) An FFS device was assembled in which two substrates were pasted together, the surfaces of the alignment films were inside, and the directions of linearly polarized ultraviolet light were parallel, and the distance between the substrates was 4 micrometers. An injection inlet for liquid crystals was arranged to the position where the flow direction of liquid crystals was roughly parallel to the linearly polarized ultraviolet light. The liquid crystal composition in Composition Example M3 was injected in vacuum to this FFS device, and the response time and the flicker rate were measured. Table 8 summarizes the results.

Examples 30 to 34

(60) A mixed solvent of NMP/BC=4/1 (ratio by weight) was added to each of polyamic acid solutions (PA41), (PA44), (PA41), (PA33) and (PA43) with a polymer solid content of 6% by weight to give a liquid crystal aligning agent with a polymer solid content of 4% by weight. A FFS liquid crystal display device was produced according to Example 1 using the resulting liquid crystal aligning agent. The liquid crystal composition prepared in Composition Example M4 to M8 was injected to the device, and the response time and the flicker rate were measured. Table 8 summarizes the results.

(61) TABLE-US-00022 TABLE 8 Response times and Flicker rates Composition Example Polyamic acid Example Response time Flicke rate No. No. No. (ms) (%) 1 PA1 M1 20.1 0.51 2 PA2 M2 35.3 0.56 3 PA25 M3 22.1 0.34 4 PA26 M4 26.0 0.04 5 PA27 M5 35.8 0.89 6 PA28 M6 31.0 0.38 7 PA29 M7 23.0 0.80 8 PA30 M8 19.0 0.41 9 PA31 M9 20.3 0.42 10 PA32 M10 24.1 0.22 11 PA33 M11 42.5 0.19 12 PA34 M12 27.3 0.27 13 PA35 M13 17.1 0.72 14 PA36 M14 22.8 0.33 15 PA37 M1 21.3 0.56 16 PA38 M2 34.7 0.52 17 PA39 M3 22.4 0.31 18 PA44 M4 25.7 0.03 19 PA45 M5 36.1 0.91 20 PA46 M6 30.8 0.36 21 PA47 M7 22.9 0.79 22 PA27 M8 19.2 0.30 23 PA40 M9 20.4 0.57 24 PA42 M10 24.5 0.14 25 PA48 M11 41.4 0.22 26 PA34 M12 26.8 0.34 27 PA41 M13 17.3 0.59 28 PA43 M14 21.9 0.25 29 PA33 M9 19.9 0.45 30 PA41 M10 24.8 0.23 31 PA44 M11 42.2 0.16 32 PA41 M12 27.1 0.21 33 PA33 M13 18.0 0.77 34 PA43 M14 22.3 0.32

(62) In the third column of Table 8, the type of compositions injected to the FFS devices is described. These are the liquid crystal compositions prepared in Composition Example M1 to Composition Example M14. In these compositions, the maximum temperature (NI) is in the range of 70.0 C. to 117.6 C. The minimum temperature (Tc) is in the range of <10 C. to <30 C. The optical anisotropy (n) is in the range of 0.095 to 0.129. The dielectric anisotropy () is in the range of 3.1 to 15.9. The viscosity () is in the range of 10.3 mPa.Math.s to 25.5 mPa.Math.s. Fourteen liquid crystal compositions with different types of characteristics were injected to a liquid crystal display device with different types of alignment films, and then the response time and flicker rate of the device were measured.

(63) In a liquid crystal display device, a shorter response time is desirable. The response time is preferably 60 ms or less, and more preferably 40 ms or less. A smaller flicker rate is desirable. The flicker rate is preferably 2% or less, and more preferably 1% or less. The response time in Examples 1 to 34 was in the range of 17.1 ms to 42.5 ms and the flicker rate was in the range of 0.04% to 0.91%. These values fell within the more desirable ranges. From these results, we now conclude that the values of the response time and the flicker rate came within such a suitable range, although the types of components in the liquid crystal compositions and the alignment films were quite different. This is the first feature of the invention that is worthy of special mention. In the devices in Examples 7, 19, 21 and 33, the flicker rates were 0.7% or more. The response time of these devices were 23.0 ms, 36.1 ms, 22.9 ms and 18.8 ms, respectively. These findings shows that the flicker rate is small even in the devices that have short response time. This is the second feature of the invention that is worthy of special mention.

INDUSTRIAL APPLICABILITY

(64) The liquid crystal display device of the invention has characteristics such as a short response time, a large voltage holding ratio, a low threshold voltage, a large contrast ratio, a long service life and a small flicker rate. The device thus can be used for a liquid crystal projector, a liquid crystal television and so forth.