JP2000066169A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the device capable of obtaining high contrast and high color purity and also reducing vibration sound even at the time of enhancing the driving frequency by applying switching voltage to first and second electrodes only for a time shorter than the liquid crystal response time before and after polarity reversal of the applied voltage to the first and second electrodes and continuing the application of specified holding voltage to the electrodes over a specified time until the next polarity reversal. SOLUTION: This device is provided with a display section 10 and a voltage adjustment means 1, wherein: the display section 10 has a pair of substrates (11) and 12 placed opposite to each other and a liquid crystal layer 27 that is interposed between the substrates (11) and 12 and consists of a liquid crystal material of a chiral smectic C phase or its secondary phase; the voltage adjustment means 1 has a voltage application means 2 for applying switching voltage of an optional value between a holding voltage value applied to first electrodes 13 and a holding voltage value applied to second electrodes 14, only for a time shorter than the liquid crystal response time before and after polarity reversal of applied voltage 51 to the first electrodes 13 and the second electrodes 14; and further, this voltage adjustment means 1 also has a voltage holding means 3 for continuing the application of specified holding voltage to the first and second electrodes 13 and 14 over a specified time until the next polarity reversal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device using a ferroelectric liquid crystal, an antiferroelectric liquid crystal, or the like.
The present invention relates to a liquid crystal display device having a liquid crystal layer made of a liquid crystal material of a chiral smectic C phase or a subphase thereof sandwiched between two substrates.

[0002]

2. Description of the Related Art In recent years, in order to realize a low-cost color display device, a monochrome CRT (monochromatic Cathode Ray Tube), which does not require a shadow mask and requires only one electron gun, has been developed.
Several methods for combining with a field sequential liquid crystal color shutter have been studied. Such a monochrome CRT
The system that combines the LCD and the color shutter is a CRT
The fluorescent screen is solid and the system does not depend on the pixel pitch.
In addition, there is an advantage that a large size is easy because a high-precision material and a manufacturing method are unnecessary. When realizing color display by the field sequential method, usually red (R)
In order to display three colors of green (G) and blue (B) for each frame of the display image, a standard value of a frame rate of 60 Hz is used.
Is driven at 180 Hz which is at least three times the frequency of the above.

However, at a driving frequency of 180 Hz, when displaying a moving image, there is a problem that color breakage is visually recognized when the line of sight of the viewer moves or the viewer blinks. . In order to solve this problem, it is considered that a driving frequency of about 540 Hz which is at least 9 times the standard value is required. in this way,
In order to increase the driving frequency, the optical switching speed of the liquid crystal needs to be about 0.3 ms or less. However, such high-speed switching is impossible with a nematic liquid crystal material such as a pi-cell which has been conventionally used mainly for a liquid crystal shutter.

For this reason, it is necessary to use a ferroelectric liquid crystal or an antiferroelectric liquid crystal having spontaneous polarization and having a large torque due to an applied electric field and a high speed, instead of a nematic liquid crystal material. A liquid crystal shutter using these liquid crystal materials (more generally, a liquid crystal of a chiral smectic C phase or a sub-phase thereof) uses a birefringence mode in which an optical axis parallel to a liquid crystal layer surface changes its direction by an electric field. It is driven by a system called. In the case of the simplest monochrome black and white binary shutter, a cell is installed between neutral polarizing films in a crossed Nicols arrangement, and the optical axis is 0 degree and 45 degrees with respect to the polarization axis of one polarizing film. When the switching is designed so as to achieve the highest contrast, the highest contrast can be obtained.

In the case of a color shutter, a plurality of color polarizing films and a plurality of liquid crystal cells are used. The arrangement of the optical axis of the liquid crystal cell with respect to the polarizing axis of each polarizing film is the same (Eurodisplay '84). digest, pp.7). In ferroelectric liquid crystals and antiferroelectric liquid crystals, the movement of molecules due to an electric field is limited on the conical surface, and in a cell with a narrow gap, the switching angle in the liquid crystal layer is the cone angle of this cone. Almost correspond, called tilt angle ± 3
Most are below 0 degrees. Therefore, 45
In order to obtain a switching angle of degree, the tilt angle must be ± 2.
The material must be designed to be 2.5 degrees. Ferroelectric liquid crystal and antiferroelectric liquid crystal are designed to be bistable and tristable in a cell with a narrow gap, and to be stable in two states with a tilt angle of ± 22.5 degrees. It is possible to

FIG. 15 schematically shows driving of a conventional liquid crystal shutter using a ferroelectric liquid crystal or an antiferroelectric liquid crystal. FIG. 15 is a diagram illustrating an example of a driving sequence of the liquid crystal shutter and display colors. By inputting a voltage waveform having a period of 1/180 second and an amplitude V as shown in 73 to 78 to each stripe electrode of the two liquid crystal cells 71 and 72 to be superimposed, a short black display period is provided therebetween. , Three meals of RGB can be displayed in order. By setting the black display period to 1/3 of each color display period, the DC component of the voltage waveform can be eliminated. The counter electrode 14 was grounded to a constant potential. Scroll display is performed by inputting waveforms with phases shifted to the six divided stripe electrodes.

[0007] It is known that liquid crystals are susceptible to temperature fluctuations due to use environment such as seasonal conditions and continuous use time. Further, the tilt angle also has temperature dependence, and the extinction position changes due to a change in temperature, so that light leakage in the black state increases and the contrast decreases.
Further, it is difficult to finely adjust the shift of the extinction position in an analog manner by using an applied voltage in the case of a bistable or tristable state such as a conventional ferroelectric liquid crystal or antiferroelectric liquid crystal material. In addition, the rotation of the smectic layer may occur accidentally due to long-time driving, and a shift in the extinction position due to this may also cause a decrease in contrast. With an asymmetric drive waveform, the smectic layer rotation can be controlled reversibly.

However, the generated layer rotation gradually progresses as the drive is performed for a long time as long as the drive is performed with the same waveform, and the contrast continues to decrease, so that normal display becomes impossible. In addition, since ferroelectric liquid crystals and antiferroelectric liquid crystals have piezoelectricity and electrostriction, when a liquid crystal cell is driven by a rectangular wave, a sound is generated at the time of polarity reversal. With the high-speed shutter as described above, several hundred Hz
However, there is also a problem that the vibration sound in the audible range is not preferable as a display element.

As described above, when a conventional ferroelectric liquid crystal or antiferroelectric liquid crystal material is used, there is a problem in stability of contrast in a monochrome shutter, and a problem in stability of color purity in a color shutter. there were.

Further, when a ferroelectric liquid crystal or an antiferroelectric liquid crystal is used, the capacity of a liquid crystal cell is increased by about one digit as compared with the case of a paraelectric liquid crystal such as a pi cell, so that a large-sized display element is used. However, there is a problem in that the time constant increases due to an increase in the resistance value of the wiring or the transparent electrode, and a sufficient response speed cannot be obtained in the central portion of the screen even when power is supplied from both ends of the screen. This makes it impossible to increase the drive frequency to 540 Hz, making it difficult to avoid color breakup. In addition, as a problem inherent to the ferroelectric liquid crystal and the antiferroelectric liquid crystal, there is also a problem that the alignment breakdown and the impact resistance are insufficient.

[0011]

As described above, in a conventional liquid crystal display device used for a ferroelectric liquid crystal / anti-ferroelectric liquid crystal shutter or the like, first, when a liquid crystal cell is driven by a rectangular wave, vibration occurs at a high speed operation. There was a problem that sound was generated. Further, the monochrome shutter has a problem in stability of contrast, and the color shutter has a problem in stability of color purity. Further, there is a problem that the driving frequency cannot be increased and color breakup cannot be avoided.

According to the present invention, when used in a ferroelectric liquid crystal / anti-ferroelectric liquid crystal shutter, high-speed operation provides a stable and high contrast as compared with the prior art, and high color purity when used in a color display device. It is another object of the present invention to provide a liquid crystal display device that can obtain vibration and reduce vibration noise even when the driving frequency can be increased.

[0013]

In order to achieve the above object, a liquid crystal display device according to the first aspect of the present invention comprises two
A substrate, a liquid crystal layer containing a liquid crystal material of a chiral smectic C phase or a sub-phase thereof sandwiched between the two substrates, a first electrode provided on one of the substrates, A second electrode provided on the other side of the substrate opposite to the first electrode, wherein the liquid crystal response time before and after the polarity reversal of the voltage applied to the first and second electrodes is shorter than the liquid crystal response time. Voltage applying means for applying a switching voltage having an arbitrary value between one holding voltage and the other holding voltage, and voltage holding means for continuously applying a constant holding voltage for a certain period until the next polarity inversion. And a voltage adjusting means including:

According to a second aspect of the present invention, in the liquid crystal display device according to the first aspect, a temperature detecting means for detecting a change in the temperature of the liquid crystal layer, or the first and second liquid crystal layers.
Current detecting means for detecting a change in the current supplied to the electrodes, wherein the voltage adjusting means is configured to detect the change in the temperature detected by the temperature detecting means or the change in the extinction position detected by the current detecting means. It is characterized in that the switching voltage is changed. By changing the switching voltage in this way, it is possible to suppress fluctuations in the time required for switching the liquid crystal at the time of polarity inversion, regardless of the temperature level, and to make the switching operation of the applied voltage gentle.

According to a third aspect of the present invention, there is provided a liquid crystal display device comprising: two substrates disposed so as to face each other; and a chiral smectic C phase or a subphase liquid crystal material sandwiched between the two substrates. A liquid crystal layer comprising: a first electrode provided on one of the substrates; and a second electrode provided on the other of the substrates opposite to the first electrode. Temperature detecting means for detecting temperature fluctuations of
Alternatively, current detection means for detecting a change in current supplied to the first and second electrodes, and a change in the temperature of the liquid crystal layer detected by the temperature detection means, or extinction detected by the current detection means Voltage applying means for applying a voltage while changing a switching voltage for inverting the polarity of the voltage applied to the first and second electrodes in accordance with the position change, and the voltage applying means for a certain period until the next polarity inversion. And a voltage adjusting means including a voltage holding means for continuously applying a constant holding voltage to the first and second electrodes.

The liquid crystal display device according to any one of the first to third aspects of the present invention is arranged so that the temperature fluctuation or the extinction position fluctuation detected by the temperature detecting means or the current detecting means is compensated. The voltage applying means may be configured to adjust the voltage applied to the first and second electrodes.

According to a fourth aspect of the present invention, there is provided a liquid crystal display device as set forth in any one of the first to third aspects.
The liquid crystal layer has an optical axis switching angle of at least 45 degrees at room temperature or a lower temperature range, and the liquid crystal layer does not have an antiferroelectric liquid crystal, a distorted helical ferroelectric liquid crystal, or a polymer mixed therein. It is characterized in that it contains any one of a dielectric liquid crystal and an antiferroelectric liquid crystal.

According to a fifth aspect of the present invention, there is provided a liquid crystal display device according to any one of the first to third aspects.
The liquid crystal layer is configured such that the first and second electrodes are formed of striped electrodes having optical transparency, and a part of the striped electrodes is provided with a metal auxiliary wiring,
It is characterized in that the metal auxiliary wirings of two adjacent cells are displaced from each other.

In the case of the above construction, the IT
By providing the metal auxiliary wiring above or below the O electrode layer, the electrode resistance becomes lower as compared with the case where only the ITO transparent electrode is provided, so that an increase in the time constant can be avoided.
High-speed driving is possible even for a large-sized display element. The metal auxiliary wiring is hardly visually recognized by making the pixel size smaller than the pixel size of the monochrome display device on the rear surface, and does not affect display quality of an image. However, when the thickness is extremely thin, the effect of lowering the resistance is small, and when the thickness is too thick, the wirings of the two cells overlap depending on the viewing angle, and the display quality is reduced due to visual recognition. Therefore, by displacing the wiring of the two cells as in this configuration, the effect of lowering the resistance can be increased without deteriorating the display quality.

Further, in the structure according to the fifth aspect, a spacer wall having an adhesive property between the substrates may be provided at a position overlapping with the metal auxiliary wiring. As described above, if the spacer member having adhesiveness is provided at a position overlapping with the opaque metal auxiliary wiring, the effect of improving the shock resistance can be obtained without visually recognizing the poorly-aligned portion of the spacer portion and the vicinity portion of the spacer. can get.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a liquid crystal display device according to the present invention will be described below in detail with reference to the accompanying drawings. The following embodiments are described for the purpose of facilitating the understanding of the present invention, and it is needless to say that various modifications and changes can be made without departing from the spirit of the present invention. .

First, a liquid crystal display device according to a first embodiment as a basic concept of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. FIG. 1 is a block diagram illustrating a schematic configuration of the liquid crystal display device according to the first embodiment. FIG.
, The liquid crystal display device includes a display unit 10 and a voltage adjusting unit 1 for supplying a drive voltage to the display unit 10. First, the display unit 10 includes two substrates 11 opposed to each other. , 12, a liquid crystal layer 27 of a chiral smectic C phase or its sub-phase liquid crystal material sandwiched between these two substrates, and a first electrode 13 arranged in a predetermined state on the substrates. A second electrode 14 arranged in a predetermined state on the substrate so as to face the first electrode 13.
And

Next, the voltage adjusting means 1 applies one holding voltage and the other holding voltage for a time shorter than the liquid crystal response time before and after the polarity inversion of the voltage 51 applied to the first and second electrodes 13 and 14. A voltage applying means 2 for applying a switching voltage having an arbitrary value between the voltage and a voltage, and a voltage holding means 3 for continuously applying a fixed holding voltage for a certain period until the next polarity inversion.

In the above configuration, no measure is taken for the temperature change of the display unit 10. However, in the liquid crystal display device, the temperature is relatively low when the power is turned on and the temperature after the continuous use. Is increased, it is more effective to change the manner of supplying the switching voltage during the polarity inversion. Therefore, a temperature detector 36 as a sensor for detecting a change in the temperature of the liquid crystal layer 27,
Temperature detecting means 4 for supplying the detection signal detected by the temperature detecting section 36 to the voltage applying means 2 may be provided. The voltage application unit 2 is configured to change the temperature of the liquid crystal layer detected by the temperature detection unit 4 in accordance with a change in the temperature of the liquid crystal layer.
The voltage is applied while changing the switching voltage for inverting the polarity of the voltage applied to the electrodes 13 and 14. The voltage holding means 3 keeps applying a constant holding voltage to the first and second electrodes 13 and 14 for a certain period until the next polarity inversion.

The first and second electrodes 13 and 14 are replaced with the temperature detecting means 4 for detecting temperature fluctuation.
Current detecting means 5 for detecting a change in the current supplied to the power supply may be provided. The voltage applying means 2 controls the first and second electrodes 1 so as to compensate for the extinction position fluctuation based on the current indirectly detected by the current detecting means 5.
The voltage applied to 3, 14 is adjusted. Note that the current detecting means 5 may be provided for a device including the temperature detecting means 4. Further, a clock signal for switching the holding voltage at a constant cycle is supplied to the voltage applying means 2 and the voltage holding means 3 of the voltage adjusting means 1. Further, a read-only memory (ROM-Read Only Memory) for storing a reference temperature value or a reference current value serving as a reference for obtaining the fluctuation width of the detected temperature fluctuation or extinction position fluctuation.
-) 6 are also provided.

The overall configuration of the liquid crystal display device according to the first embodiment having the above basic configuration will be described with reference to FIGS. FIG. 3 shows the entire configuration of the liquid crystal display device according to the first embodiment. In FIG. 3, a liquid crystal display device 7 includes an input circuit 7A to which a VTR signal and AC power are supplied, and a CRT functioning as a drive and control circuit.
Circuit 8, a CRT 9 driven and controlled by the CRT circuit 8, a shutter circuit 1 functioning as a voltage adjusting means, and a liquid crystal shutter 10 driven and controlled by the shutter circuit 1. .

As shown in FIGS. 4 and 5, the liquid crystal shutter 10 comprises a front glass substrate 11 (22a) and a facing (back) glass substrate 12 (22b), and is manufactured by the following method. As a substrate material, a material other than glass, for example, polyethersulfone (PES)
Or a combination of different materials and substrates having different thicknesses. Front substrate 11 (22a)
Is a 1.1 mm-thick non-alkali glass, on which are formed six stripe-shaped ITO stripe electrodes 13 (23a) having a thickness of 130 nm by sputtering, photolithography and etching processes. Have been.

In FIG. 5, reference numerals 23a and 23b denote front and rear ITO electrodes, respectively.
3b, the front and back inorganic insulating films 24a,
24b, and the polyimide alignment films 25a, 2b on the front and back sides are sandwiched between the inorganic insulating films 24a, 24b.
5b is provided. Polyimide alignment film 25a, 25
b, spherical spacers 26 are provided at regular intervals,
A liquid crystal layer 27 is provided by the spherical spacer 26. Metal auxiliary wirings 31 are provided at predetermined intervals on the ITO electrodes 23a, and spacer members 32 are provided at locations in the liquid crystal layer 27 corresponding to the auxiliary wirings 31.

In the above configuration, first, the metal auxiliary wiring 3
The two liquid crystal shutters whose positions and directions are different from each other by 45 ° are combined in a positional relationship as shown in FIG. 6, and a chromatic polarizing film is disposed between two cells and before and after to form a field sequential color shutter. 3 was installed in front of a monochrome CRT to provide a color display device as schematically shown in FIG. Thin dark lines made of opaque metal auxiliary wiring are almost invisible regardless of the viewing angle,
The level was practically no problem.

As shown in FIG. 7, for example, the metal auxiliary wiring 31 may be provided in parallel with the longitudinal direction of the stripe electrode so that the two cells do not overlap. FIG. 8 shows an example of a cross-sectional view perpendicular to the longitudinal direction of the stripe electrode in this case. For example, when a PES substrate having a thickness of 0.1 mm is used as a substrate constituting a cell, 2
If the distance in the in-plane direction of the metal auxiliary wiring of one cell is 1 mm or more, the wirings do not overlap with each other at a viewing angle of 120 ° or more, and interference is not visually recognized. In this case, the rubbing direction may be the direction shown in FIG. 7 or may be shifted by 22.5 ° from the cell longitudinal direction as in FIG.

The normal operation of the liquid crystal display device according to the first embodiment as shown in FIGS. 3 to 8 is the same as the driving sequence of the conventional ferroelectric or antiferroelectric shutter described with reference to FIG. The liquid crystal shutter is driven according to the relationship with the display color. However, the waveform of the switching voltage is
It is controlled so as to change in a step-like manner as shown in FIG.

Next, a liquid crystal display according to a second embodiment of the present invention will be described in detail with reference to FIGS. FIG. 9 is a block diagram of a driving circuit for a color display device and a liquid crystal shutter in the liquid crystal display device according to the second embodiment. Perpendicular to the original RGB signal,
Control synchronization signal (CL
When K) is input, the control signal is converted into n-times speed by the double-speed conversion circuit 62 and input to the driver of the CRT display unit 66 in accordance with the n-folded field period. The RGB parallel signal is input to the driver as an RGB serial signal whose frequency is multiplied by n by the parallel-serial double speed conversion circuit 61, and sequentially displays a desired RGB image at high speed.

On the other hand, a double-speed control signal is input from the double-speed conversion circuit 62 to the control circuit 63, and six-phase drive signals for operating the liquid crystal color shutter are supplied to the liquid crystal cells 67 and 68.
Is input to The temperature of the liquid crystal cell portion is detected by a temperature detector 64 and input to the control circuit 63.
The control circuit refers to the memory 65 storing the temperature-drive voltage conversion table, sets the drive voltage amplitude in FIG. 16 to a value corresponding to the detected temperature, and outputs the value to the liquid crystal cell.

FIG. 10 is a diagram showing an example of the driving sequence of the liquid crystal shutter and the display colors in which the measures for reducing the vibration noise have been taken. A period 1/18 as shown in 73 to 78 is applied to each stripe electrode of the two liquid crystal cells 71 and 72 to be superimposed.
The point of inputting a voltage waveform of 0 second is the same as the example in FIG. 15, but in this example, the first 10
The amplitude of the switching voltage Vi applied during 0 μs is smaller than the amplitude of the holding voltage Vh. As a result, the optical response waveform was gradual, the vibration noise was suppressed to a level without practical problems, and a switching speed of 0.3 ms or less sufficient to obtain excellent display performance was obtained.

In order to reduce the vibration noise, it is also effective to reduce the switching voltage and to make the waveform different from the one-step waveform, for example, a multi-step waveform or tapered waveform. However, the method of setting the switching voltage low as in the second embodiment is the simplest and is preferable in terms of the circuit configuration.

The coloring means as a color display device is not limited to a color polarizing film but may be a dichroic dye mixed in a liquid crystal layer. In the case of the guest-host system using such a dye and liquid crystal, the liquid crystal cell contains cyan, magenta, and yellow dyes, respectively.
It is preferable that the number of cells is six, or the three cells are two and the number of cells is two, and the cells are arranged so that the light absorption axes are orthogonal to each other. By optimizing the dichroic ratio and spectrum of the dye material in accordance with the spectrum of the phosphor of the monochrome CRT, there is an advantage that a higher transmittance can be obtained as compared with the case where a color polarizing film is used.

As the liquid crystal material, a smectic liquid crystal material, such as a non-ferroelectric liquid crystal, a distorted helical ferroelectric liquid crystal, or a polymer, which is a smectic liquid crystal material in which the direction of the optical axis changes almost in proportion to the applied electric field, is mixed. Either a ferroelectric liquid crystal or an antiferroelectric liquid crystal described above is preferable. Since these have characteristics capable of displaying an analog gradation, it is easy to compensate for the extinction position shift by finely adjusting the applied voltage. Since the tilt angle decreases as the temperature rises, it is desirable to use the above liquid crystal material having a switching angle of at least 45 degrees at room temperature or a lower temperature range in order to obtain high contrast. As a non-threshold antiferroelectric liquid crystal, for example, a mixed liquid crystal as shown in Chemical Formula 1 is known (J. Mater. Chem., Vol. 6, pp. 671 (1996)).

[0038]

Embedded image As a distorted helical ferroelectric liquid crystal, for example, a mixed liquid crystal as shown in [Chemical Formula 2] is known (JP-A-10-969).
No. 65).

[0039]

Embedded image Ferroelectric liquid crystal mixed with a polymer, for example, Furue et al;
Reported by SID '98 Digest p-78. As a monomer to be mixed to form a polymer, for example, liquid crystalline acrylate monomers (monoacrylate, diacrylate) shown in [Chemical Formula 3] are known.

[0040]

Embedded image A ferroelectric liquid crystal having a cone angle close to 45 ° and suitable for shutter use is, for example, CS
-1011, CS-1014, CS-1026, CS-
1028 are known. As the antiferroelectric liquid crystal, for example, MHPOBC as shown in [Formula 4] is known, but a mixed liquid crystal of a plurality of liquid crystal components including the antiferroelectric liquid crystal may be used.

[0041]

Embedded image As a comparative example of the second embodiment, a cell having no metal auxiliary wiring was prepared, and a color shutter was formed under the same conditions as those of the second embodiment. The switching speed becomes slower toward the center of the screen in the low temperature range or under conditions equivalent to a large cell of 40 inches or more, and the switching speed becomes 1 ms
As a result, the color display device suffered from the problem of color breakup, and display unevenness was generated, and the level became unpractical.

Next, two cells having a metal auxiliary wiring at the same position in the longitudinal direction of the stripe electrode are placed in the second cell.
A display was created by the same method as in the embodiment, and a color shutter was constructed by combining two of them. High-speed response was realized, and color breakage was reduced to a level that did not cause a problem as a color display device. However, depending on the viewing angle, the dark lines of the metal auxiliary wiring overlapped in the two cells, and the dark lines might be noticeable as interference, The quality is lower than that of the liquid crystal display device of the second embodiment.

Next, a cell having no spacer wall at a position overlapping with the metal auxiliary wiring was prepared, and the other conditions were the same as those of the second embodiment to form a color shutter, and a display device was prepared. The display performance was equal to that of the liquid crystal display device according to the second embodiment, but the impact resistance was lower than that of the second embodiment, and the alignment test was more likely to occur in the impact test.

Next, a liquid crystal display device according to a third embodiment of the present invention will be described with reference to FIGS. First, the configuration of the liquid crystal cell will be described with reference to FIGS. In FIG. 11, the liquid crystal cell is
It is composed of a front glass substrate 11 (22a) and a facing (back) glass substrate 12 (22b), and is manufactured by the following method. On the front substrate 11 (22a), a thickness of 130
An ITO stripe electrode layer 13 (23a) formed of 25 horizontal stripes of 25 nm is formed, and a 100 nm thick SiO ₂ layer 24a is formed on the electrode layer 13 (23a) by sputtering. I have.

The opposing substrate has a thickness of 130 n over the entire surface excluding the end portions.
m, an ITO counter electrode layer 14 (23b) is formed, and a 100 nm thick SiO ₂ layer is formed on the electrode layer 14 (23b) by sputtering.
On the SiO ₂ layers 24a and 24B of each substrate, a low pretilt polyimide film 25 as a liquid crystal alignment film is provided.
a and 25b are formed to a thickness of 60 nm. The polyimide films 25a and 25b as alignment films of each substrate are:
Rubbing is performed at an angle shifted from the longitudinal direction of the cell by 22.5 degrees in the direction opposite to the liquid crystal injection direction. However, the rubbing axes of both substrates are shifted by about 10 degrees.

Next, a cell gap of 2.0 μm is provided by spraying a silica spacer 26 coated with a resin. At 25 ° C., an antiferroelectric liquid crystal A having a spontaneous polarization of 100 nC / cm ² , a response time of 150 μs, a saturation voltage of 15 V, and a tilt angle of 27 degrees (cone angle of 54 degrees) is used as a liquid crystal material. 2
7 was formed. The cone angle has a temperature dependency 41 as shown in FIG. Polarizing plates 21a and 21b are attached outside glass substrates 22a and 22b, respectively. The polarization axes of the polarizers are denoted by reference numerals 15 and 16 in FIG.
Direction.

When a polarizing plate is used as a monochrome shutter, a neutral polarizing plate is applied, and when used as a color liquid crystal shutter, a color polarizing plate is used. Since the extinction position detector 35 shown in FIG. 11 has a photodiode provided outside the neutral polarizing plate, the amount of transmitted light can be measured, and feedback is performed so that the amount of transmitted light is minimized during black display. It is connected to a mechanism for controlling the drive voltage by controlling.

As the light source for detection, a signal light source such as a part of a monochrome CRT display can be used, for example, but a light source for detection independent of such a signal light source can also be provided. . Further, the light source for detection can be made to blink so as to have a constant light amount at the time of detection, and the light amount at the time of detection can be separately detected and standardized for use. Further, it is sufficient to perform the detection about once every several tens seconds to several minutes. By using a mechanism including such detection means and voltage adjustment means, the voltage is adjusted so that the optical axis direction of the liquid crystal when a positive voltage is applied matches the polarization axis direction 16 of one polarizing plate. . That is, the voltage is adjusted so that the switching angle is not affected by the temperature-dependent characteristic as indicated by the broken line 43 in FIG.

The driving system driven by the applied voltage has a maximum applied voltage of ± 15 V. A rectangular wave having an amplitude of 10 to 15 V adjusted as described above is input to each stripe electrode 13 and the counter electrode 14 is grounded to maintain a constant potential. Since the monochrome shutter has a good black state without depending on the temperature, as shown by the solid line 44 in FIG. 13, a high value such that the contrast ratio is always "200: 1" was obtained. When used as a color shutter, high color purity can be obtained. By combining with a monochrome CRT, a high-quality image display device can be obtained as a display element.

Depending on the combination of the alignment film and the liquid crystal material,
An extinction position shift may occur due to the rotation of the smectic layer due to long-term use.However, fluctuation detection means for detecting the extinction position fluctuation or temperature fluctuation, and extinction position fluctuation or temperature fluctuation detected by the fluctuation detection means are used. And a voltage adjusting means for adjusting the applied voltage to the first and second electrodes so as to compensate for the change in the driving waveform by rotating the liquid crystal layer in the opposite direction by always adjusting the driving waveform. Since a force acts to return the extinction position to the initial layer normal direction, it is possible to suppress the occurrence of the extinction position shift even after long-term use.

Next, a liquid crystal display device according to a fourth embodiment of the present invention will be described with reference to FIGS. In FIG. 11, the liquid crystal cell includes a front glass substrate 11 (22a) and a facing (back) glass substrate 12 (22a).
b) and is manufactured by the following method.
As the substrate material, a material other than glass, for example, a plastic such as PES may be used, or a substrate having a different material and a different thickness may be combined. The surface substrate 11 (22a) is a non-alkali glass having a thickness of 1.1 mm, and has a stripe electrode of ITO formed thereon in a shape of 25 horizontal stripes having a thickness of 130 nm by a process of sputtering, photolithography, and etching. 13 (23a) are formed.

The interval between the stripe electrodes 13 is about 20 μm. On the ITO stripe electrode 13, a 100 nm-thick SiO ₂ film is formed as an insulating layer over the entire surface.
The film 24a is formed by sputtering. Other materials for forming the insulating layer include SiN, Ta ₂
O _5, etc. SrTiO _3, TiO ₂ is considered, the insulating film may be a multilayer film may be a single layer film. The opposing substrate 12 is made of 1.1 mm-thick non-alkali glass, and has a 130 nm-thick ITO opposing electrode 14 (23b) on the entire surface excluding the end by sputtering, photolithography and etching. are doing.

An SiO ₂ film 24 having a thickness of 100 nm is formed on the entire surface of the stripe electrode 13 made of ITO.
b was formed by sputtering. SiO ₂ layers 24a, 2 of each substrate
4b, low pretilt polyimide films 25a and 25b were formed as liquid crystal alignment films to a thickness of 60 nm. As the liquid crystal alignment film, besides this, polyvinyl alcohol, polyamide imide, or the like may be used. The alignment film of each substrate was rubbed at an angle shifted from the cell longitudinal direction by 22.5 degrees in the direction opposite to the liquid crystal injection direction. However, the rubbing axes of both substrates were shifted by about 10 degrees in consideration of the difference between the rubbing direction and the normal of the smectic layer of the liquid crystal. Further, a spherical silica spacer 26 coated with a resin having a diameter of 2.0 μm was sprayed on the front substrate 11.

The material of the spherical spacer may be a hard plastic or an adhesive material.
Further, the adhesive spacer and the non-adhesive spacer may be mixed and sprayed. An epoxy adhesive was applied to the periphery of the opposing substrate for bonding, and was fixed under heat and pressure to form cells. As a liquid crystal material, an antiferroelectric liquid crystal A having a spontaneous polarization of 100 nC / cm ^{2 at} 25 ° C., a response time of 150 μs, a saturation voltage of 15 V, and a tilt angle of 27 degrees (cone angle of 54 degrees) is used. 27 was formed. As the liquid crystal material, a ferroelectric liquid crystal or an anti-ferroelectric liquid crystal having no hysteresis or memory property is preferable.For example, there is a distorted helical ferroelectric liquid crystal or a ferroelectric liquid crystal mixed with a polymer. Depending on the case, a liquid crystal having hysteresis may be used.

The injection method may be another method such as suction injection. Outside the glass substrates 22a and 22b,
The polarizing films 21a and 21b were stuck respectively. The polarization axis of the polarizing film was set in the directions indicated by arrows 15 and 16 in FIG. When the polarizing film is used as a monochrome shutter, a neutral polarizing film is used. When the polarizing film is used as a color shutter, a color polarizing film is used. In order to improve color range characteristics and viewing angle characteristics,
A retardation film may be used in addition to the polarizing film.

The driving system used had a maximum applied voltage of ± 20 V. A voltage according to the drive waveform 51 shown in FIG. 2 was applied to each stripe electrode 13. The waveform 51 has a switching voltage at the time of polarity inversion of 4 V in amplitude and a holding voltage of 12 V. The counter electrode 14 was grounded to a constant potential. As a result,
The optical response waveform 52 was gentle, the vibration noise was suppressed to a level that would not cause any practical problem, and a switching speed of about 0.3 ms sufficient to obtain excellent display performance was obtained.

Further, in order to compensate for the temperature dependence of the switching angle of the liquid crystal, the switching voltage is about 20 V at a low temperature of 0 ° C. to 10 ° C. and about −5 V at a high temperature of 50 ° C. to 60 ° C. As described above, the switching voltage may be continuously changed according to the temperature.
For temperature detection, a temperature sensor, an indirect sensor based on detection of a switching current peak having temperature dependency, and the like can be used. As a result, the vibration noise is suppressed independently of the temperature, and as a monochrome shutter, the black state is excellent independently of the temperature and the contrast ratio is always 200:
A high value of 1 was obtained.

By combining the above two liquid crystal shutters,
A field-sequential color shutter was formed by arranging a color polarizing film between and before and after the two cells, and was installed in front of a monochrome CRT to obtain a color display device. A cushioning material was used for fixing the cells, and silicon grease for vibration isolation was injected between the two cells. The shutter portion can be driven at a high speed of 9 times or more that of a 60 Hz display image, and the vibration noise is reduced to a level that does not cause a problem.
Almost no color breakup was observed, high color purity was obtained as a color shutter, and high-quality image display was realized with a display element combined with a monochrome CRT.

As a comparative example of the liquid crystal display device according to the fourth embodiment, a cell was prepared under the same conditions as in the fourth embodiment. The applied voltage is adjusted according to the temperature dependence of the switching angle of the liquid crystal, and the driving waveform 53 as shown in FIG.
As a result, the optical response showed a steep switching characteristic with a response time of about 0.2 ms as shown by a waveform 54. The switching speed was insufficient in the low temperature range, and the vibration sound was generated in the high temperature range, and the level was not practical.

By adjusting the holding voltage in accordance with the temperature dependence of the switching angle of the liquid crystal, FIG.
As shown in (b), when the driving was performed by the driving waveform 55 in which the switching voltage was set higher than the holding voltage at any temperature, the optical response showed a steep switching time of about 0.1 ms as shown by the waveform 56. Characteristics. Although a sufficient switching speed was obtained from the low temperature range to the high temperature range, the vibration sound was loud especially in the high temperature range, and the level became unpractical.

Next, a liquid crystal display device according to a fifth embodiment of the present invention will be described with reference to FIGS. The liquid crystal display device according to the fifth embodiment includes a third
Since the basic configuration of the liquid crystal display device according to the embodiment is similar to that of the liquid crystal display device according to the embodiment, the basic configuration of FIG. 11 and FIG. The liquid crystal display device according to the third embodiment adjusts the applied voltage by detecting the extinction position of the liquid crystal layer. However, the liquid crystal display device according to the fifth embodiment uses the temperature dependence of the optimal drive voltage as data in advance. In addition, the drive voltage is adjusted by detecting the temperature of the liquid crystal layer and comparing it with data.

First, the difference in the basic configuration will be described. In the third embodiment, the number of stripe electrodes is 25, but in the liquid crystal device according to the fifth embodiment, the stripe electrodes 13 (23a ) Are five. In the first embodiment, the antiferroelectric liquid crystal A having a response time of 150 μs and a tilt angle of 27 degrees (cone angle of 54 degrees) is used as the type of liquid crystal. In the response time 120
It is assumed that a distorted helical ferroelectric liquid crystal B having a tilt angle of 25 degrees (cone angle of 50 degrees) in μs is used.

As described above, as a feedback mechanism for adjusting the voltage applied to the electrode, which is the most significant feature of the fifth embodiment, the temperature of the optimum driving voltage that minimizes the amount of transmitted light during black display. The dependence is prepared in advance as data, and as shown in FIG.
The temperature is detected by a temperature detecting unit 36 provided at an arbitrary position of No. 3, and the drive voltage is adjusted based on the detected temperature.

In the liquid crystal display device according to the third embodiment, an extinction position detecting means 35 is provided as a detecting means.
In the liquid crystal display device of the second embodiment, the temperature detecting means 3
6, the present invention is not limited to this, and the extinction position detecting means 35 and the temperature detecting device 35 may be used as in the liquid crystal display device according to the fifth embodiment having the configuration shown in FIG. It is good also as a structure provided with both the means 36. With such a configuration, it is possible to more accurately detect and adjust the deviation of the driving voltage.

Two comparative examples will be described to explain the functions and effects of the liquid crystal display devices according to the third to fifth embodiments. First, as a first comparative example, a cell was prepared under the same conditions as in the first embodiment except that an antiferroelectric liquid crystal used for a shutter having a box-shaped hysteresis and having a memory property was used. The liquid crystal display was driven under the same conditions as in the first embodiment. According to the first comparative example, in the case of the monochrome shutter, the black state was insufficient depending on the temperature, and the contrast varied from 200 to 50 depending on the temperature. Further, in the case of a color shutter, there is a problem that the color purity is reduced depending on the temperature.

Since the antiferroelectric liquid crystal according to the first comparative example has a temperature dependence of the cone angle (see reference numeral 42 in FIG. 4) and has a characteristic that cannot perform analog gradation display, It is impossible to adjust the extinction position by adjusting the voltage to obtain the switching angle as shown by the broken line 43 in FIG. 13, and the contrast ratio is greatly reduced as shown by the curve 45 in FIG. did.

As a second comparative example, a node was created under the same conditions as in the liquid crystal display device according to the first embodiment, and driving was performed with the same voltage amplitude regardless of the temperature. According to the second comparative example, in the case of the monochrome shutter, the black state was insufficient and the contrast was reduced from 200 to 50. In the case of a color shutter, the color purity was significantly reduced depending on the temperature. Temperature dependence of cone angle even in antiferroelectric liquid crystal having characteristics capable of analog gradation display 4
However, if the extinction position is not adjusted by adjusting the applied voltage, the switching angle shown by the broken line 43 in FIG. 13 cannot be obtained, and the switching angle shown in FIG. It can be seen that the contrast ratio is greatly reduced due to the temperature characteristics of.

Next, a liquid crystal display device according to a sixth embodiment will be described with reference to FIGS. 4, 5 and 14. The liquid crystal cell shown in FIG. 4 and FIG.
(22a) and the opposite (back side) glass substrate 12 (22b), and were manufactured by the following manufacturing method. Substrate materials include glass, polyethersulfone (PE
Plastics such as S) and polycarbonate (PC) may be used, and substrates of different materials and different thicknesses may be combined. The front substrate 11 (22a) is made of a non-alkali glass having a thickness of 1.1 mm, and has a thickness of 13 mm by sputtering, photolithography and etching.
It has an ITO stripe electrode 13 (23a) formed in six horizontal stripes of 0 nm.

The interval between the stripe electrodes is about 20 μm. On the ITO electrode layer 13 (23a), a plurality of metal auxiliary electrode wirings 31 having a width of 20 μm are formed in the longitudinal direction for each ITO stripe electrode. As the metal electrode material, a single layer or a multilayer of Al, CI, Mo, and Mo-Ta is preferable, and the position of the wiring may be below the ITO electrode. On the ITO electrode and the metal electrode, a 100 nm-thick SiO ₂
The layer 24a was formed by sputtering. Other materials for the insulating layer include SiN, Ta ₂ O ₅ , SrTiO ₃ , TiO ₂
Or a single-layer or multi-layer film.

A photosensitive resin was applied to a thickness of 2 μm on the insulating layer, and portions other than the portion where the metal electrodes were formed were removed by photolithography to form spacer walls. The counter substrate is made of non-alkali glass having a thickness of 1.1 mm, and a counter electrode 14 (23b) of 130 nm having a thickness of 130 nm is formed on the entire surface excluding the end by sputtering, photolithography and etching. I have. A metal auxiliary electrode wiring may be formed on the ITO electrode layer 14 (23b) in the same manner as the front substrate. In this embodiment, since the power supply end of the counter electrode is up and down, the wiring direction is up and down, that is, A direction substantially orthogonal to the wiring direction of the front substrate is preferable.

On the stripe electrode 13 of ITO, a SiO ₂ layer 24 of each substrate was formed by sputtering a silicon oxide film 24 _b to a thickness of 70 nm over the entire surface.
A low pretilt polyimide film 25a, 25b was formed as a liquid crystal alignment film to a thickness of 30 nm on each of a and 24b by offset printing and baking at a temperature of about 180 ° C. to 250 ° C. As the liquid crystal alignment film, besides this, polyvinyl alcohol, polyamide imide, or the like may be used. The alignment film of each substrate was rubbed at an angle shifted from the cell longitudinal direction by 22.5 degrees in the direction opposite to the liquid crystal injection direction. However, the rubbing axes of both substrates were shifted by about 10 degrees in consideration of the difference between the rubbing direction and the normal of the smectic layer of the liquid crystal.

By arranging, in parallel or perpendicularly, a metal auxiliary wiring which is a step on the substrate surface or a spacer member which is a wall with respect to the normal direction of the smectic layer of the liquid crystal, the orientation of the liquid crystal which is easily generated in the layer direction. In order to minimize defects, it is desirable that the rubbing direction and the spacer wall direction be substantially parallel or substantially perpendicular. A spherical silica spacer 26 coated with a resin having a diameter of 20 μm was sprayed on the front substrate. The material of the spherical spacer may be a hard plastic or an adhesive material.

Further, an adhesive spacer and a non-adhesive spacer may be mixed and sprayed. An epoxy adhesive was applied to the periphery of the opposing substrate for bonding, and was fixed under heat and pressure to form cells. As a liquid crystal material, a liquid crystalline acrylate monomer U manufactured by Dainippon Ink and Chemicals, Inc.
A liquid crystal layer 27 was formed by vacuum injection using an antiferroelectric liquid crystal CS-4001 manufactured by Chisso mixed with 5 wt% of CL-001, and then irradiated with ultraviolet light of 2 mW / cm 2 for 10 minutes. The monomer was polymerized to form a polymer network in the liquid crystal layer.

As a liquid crystal material having a high speed property, a ferroelectric liquid crystal and an antiferroelectric liquid crystal having no hysteresis or memory property are preferable. For example, a ferroelectric liquid crystal with a distorted spiral type ferroelectric liquid crystal or a polymer mixed therein. Although there is a liquid crystal or the like, a liquid crystal having hysteresis may be used in some cases. The injection method may be another method such as suction injection. A polarizing film 21 is provided outside the glass substrates 22a and 22b, respectively.
a and 21b were attached. The polarization axis of the polarizing film is 1
The directions indicated by 5 and 16 were used.

When the polarizing film is used as a monochrome shutter, an achromatic polarizing film is used. When the polarizing film is used as a color shutter, a chromatic polarizing film is used. In order to improve the color range characteristics and the viewing angle characteristics, a retardation film may be used in addition to the polarizing film. The driving system used had a maximum applied voltage of ± 20 V. A rectangular wave voltage having an amplitude of 12 V was applied to terminals at both ends of each stripe electrode 13. The counter electrode 14 was grounded to a constant potential. As a result, an electrode resistance of 10Ω /
The switching speed of about 0.3 ms sufficient to obtain excellent display performance was obtained in the central part of the cell even under conditions corresponding to a cell size of 40 inches or more, which was reduced to below. In addition, the impact resistance is improved by the effect of the spacer wall provided at the position of the metal auxiliary wiring.

The operation of the liquid crystal display according to the sixth embodiment will be described. FIG. 14 shows the memory 65 in FIG.
FIG. 6 is a diagram showing an example of drive voltage amplitude correction data according to the temperature of a liquid crystal shutter, which is recorded in a memory. By optimizing the driving voltage V in FIG. 15 and the holding voltage Vh in FIG. 10 as shown by Vh in FIG. 14, the temperature dependence of the switching angle of the slow axis of the liquid crystal is eliminated.
The switching voltage in FIG. 10 is replaced by Vi in FIG.
By optimizing as shown in (1), the temperature dependence of the switching speed of the liquid crystal is eliminated, and the vibration noise can be constantly reduced. As in this example, the switching voltage may be set higher than the holding voltage in a low temperature range. As the temperature detector, not only a general temperature sensor using a change in resistance of a semiconductor or the like, but also an indirect sensor based on detection of a delay time of a switching current peak having a temperature dependency or a peak value can be used.

As a result of the above configuration, the driving of the shutter portion is reduced by the reduction in the resistance of the electrode by the metal auxiliary wiring.
High-speed driving of 9 Hz or more of a 60 Hz display image became possible, little color breakup was observed, high color purity was obtained independent of temperature, and high quality image display was realized.

[0078]

As described in detail above, according to the present invention,
Compared with the conventional monochrome shutter or color display device using ferroelectric liquid crystal and antiferroelectric liquid crystal, high-speed operation provides more stable and higher contrast and higher color purity than before, and reduces vibration noise. It becomes possible. Further, according to the present invention, compared to a monochrome shutter or a color display device using a conventional ferroelectric liquid crystal / anti-ferroelectric liquid crystal, high-speed operation is possible without impairing display quality even in a large size, Color breaks are eliminated and impact resistance is improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is a waveform characteristic diagram showing the performance of the liquid crystal display device of the first embodiment.

FIG. 3 is a block plan view schematically showing the entire color display device according to the first embodiment.

FIG. 4 is a plan view showing a liquid crystal cell constituting a liquid crystal shutter according to the first to sixth embodiments.

FIG. 5 is a sectional view showing a sectional structure of a liquid crystal cell constituting the liquid crystal shutter.

FIG. 6 is a perspective view showing a positional relationship between two cells constituting the liquid crystal shutter.

FIG. 7 is a perspective view showing a positional relationship between two cells constituting the liquid crystal shutter.

FIG. 8 is a cross-sectional view showing a positional relationship between auxiliary wirings and spacer walls of two cells which similarly constitute a liquid crystal shutter.

FIG. 9 is a block diagram showing a driving circuit for a color display device and a liquid crystal shutter in a liquid crystal display device according to a second embodiment of the present invention.

FIG. 10 is a plan view showing a drive sequence of a liquid crystal shutter and a display color together with waveforms in a second embodiment.

FIG. 11 is a plan view showing a planar structure of a liquid crystal shutter section in the liquid crystal display devices according to the third to fifth embodiments.

FIG. 12 is a sectional view showing a sectional structure of the liquid crystal shutter section shown in FIG. 11;

FIG. 13 is a characteristic diagram showing an optical response of the liquid crystal display device according to the third to fifth embodiments of the present invention in comparison with a conventional response.

FIG. 14 is a characteristic diagram showing drive voltage amplitude correction data depending on the temperature of a liquid crystal shutter in the liquid crystal display device according to the sixth embodiment.

FIG. 15 is a plan view showing a driving sequence and a display color of a conventional liquid crystal shutter together with waveforms.

16A is a waveform characteristic diagram showing a driving waveform and an optical response of a conventional liquid crystal shutter, and FIG. 16B is a waveform characteristic diagram showing a driving waveform and an optical response of a conventional liquid crystal shutter.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 voltage adjusting means 2 voltage applying means 3 voltage holding means 4 temperature detecting means 5 current detecting means 7 display device 7A input circuit 8 CRT circuit 9 monochrome CRT 10 display section 11 front glass substrate 12 back glass substrate 13 ITO stripe electrode 14 ITO Solid electrode 15 Polarization axis of front polarizer 16 Polarization axis of rear polarizer, optical axis direction of liquid crystal layer when positive voltage is applied 17 Optical axis direction of liquid crystal layer when negative voltage is applied 18 Inlet 19 Seal 21a, 21b Front and back polarizing plates 22a and 22b Front and back glass substrates 23a and 23b Front and back ITO electrodes 24a and 24b Front and back inorganic insulating films 25a and 25b Front and back polyimide alignment films 26 Spacer 27 Liquid crystal layer Reference Signs List 31 metal auxiliary wiring 32 spacer member 35 extinction position detecting section 36 temperature detecting section 51, 53, 5 the drive waveform 52, 54, 56 optical response

Continued on the front page F term (reference) 2H093 NA25 NA34 NA64 NC57 ND20 ND60 NE06 NF18 NF20 NG11 5C006 AA22 AC15 AC24 AF52 AF61 BA12 BA13 BB12 BC03 BC12 BF08 BF38 FA19 FA21 FA54

Claims (5)

[Claims] A liquid crystal layer containing a liquid crystal material of a chiral smectic C phase or its sub-phase sandwiched between two substrates, provided on one of the substrates. And a second electrode provided on the other side of the substrate opposite to the first electrode. A voltage applied to the first and second electrodes Voltage applying means for applying a switching voltage having an arbitrary value between one holding voltage and the other holding voltage for a time shorter than the liquid crystal response time before and after the polarity inversion, and for a certain period until the next polarity inversion. A liquid crystal display device comprising: a voltage adjusting unit including a voltage holding unit that continues to apply a constant holding voltage. 2. The apparatus according to claim 1, further comprising a temperature detector for detecting a change in the temperature of the liquid crystal layer, or a current detector for detecting a change in a current supplied to the first and second electrodes. 2. The liquid crystal display device according to claim 1, wherein the switching voltage is changed according to a change in the temperature detected by the temperature detecting means or a change in the extinction position detected by the current detecting means. 3. A liquid crystal layer containing a chiral smectic C-phase or a liquid crystal material of a sub-phase thereof sandwiched between the two substrates, and provided on one of the substrates. A liquid crystal display device having a first electrode provided and a second electrode provided on the other side of the substrate so as to face the first electrode, wherein a temperature detection for detecting a change in the temperature of the liquid crystal layer is performed. Means, or a current detecting means for detecting a change in the current supplied to the first and second electrodes, and a change in the temperature of the liquid crystal layer detected by the temperature detecting means, or a current detected by the current detecting means. Voltage applying means for applying a voltage while changing a switching voltage for inverting the polarity of the voltage applied to the first and second electrodes in accordance with the fluctuation of the extinction position, and a certain period until the next polarity inversion. And a voltage holding means for continuously applying a constant holding voltage to the first and second electrodes. 4. The liquid crystal layer has an optical axis switching angle of at least 45 degrees at room temperature or lower, and the liquid crystal layer does not have an antiferroelectric liquid crystal, a distorted spiral ferroelectric liquid crystal, or a polymer. 4. The liquid crystal display device according to claim 1, wherein the liquid crystal display device includes one of a ferroelectric liquid crystal and an antiferroelectric liquid crystal in which is mixed. 5. 5. A method according to claim 1, wherein said first and second electrodes are constituted by stripe-shaped electrodes having optical transparency, and a metal auxiliary wiring is provided on a part of said stripe-shaped electrodes.
The liquid crystal display device according to claim 1, wherein the metal auxiliary wirings of two adjacent liquid crystal cells are provided with displacement.