JPH06273801A - Liquid crystal electrooptical device - Google Patents

Abstract

PURPOSE:To eliminate the generation and influence of antielectric fields at the time of driving a ferroelectric liquid crystal and to improve performance by providing the respective inner surfaces of a pair of substrates facing each other with electrodes subjected to a rubbing treatment. CONSTITUTION:The electrodes 122, 123 on insulating substrates 120, 121 are subjected to the direct rubbing treatment and a smetic liquid crystal which passes through a nematic phase is held between these substrates. In this time, the liquid crystal of the phase system passing through the nematic phase having good orientability next to the isotropic phase in a high-temp. part is required to be selected. Namely, the liquid crystal passing through the nematic phase in which the molecular major axes are unified in the axial direction of orientation and which does not form a laminar structure directly from the isotropic phase is more preferable. Then, the good orientation state is obtd. if the electrodes are subjected to the direct rubbing treatment without using oriented films. The liquid crystal electrooptical device having good characteristics without being affected by the antielectric fields is produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in a liquid crystal electro-optical device using a smectic liquid crystal and further applied products thereof.

[0002]

2. Description of the Related Art A display using a liquid crystal is used in various fields from simple information display such as a clock to high-speed and large-capacity information display of a wall-mounted television.

Among the liquid crystal displays, nematic liquid crystal is particularly widely used, and is used in modes of twisted nematic (TN) liquid crystal and super twisted nematic (STN) liquid crystal. These operate according to the product of the anisotropy of the dielectric constant of the liquid crystal molecule and the square of the effective value voltage applied to the liquid crystal, and the response speed thereof is as slow as 1 to 200 msec.

On the other hand, the so-called surface-stabilized ferroelectric liquid crystal, which is used in a state where the distance between the substrates is reduced to a few μm and the liquid crystal is unwound in a helical structure, uses one state of a smectic phase and is a nematic liquid crystal. Shows a different operating mode.

The general structure of a ferroelectric liquid crystal display is described in FIG. Insulating substrate 11 such as glass
Electrodes 112 and 113 such as ITO (indium oxide oxide) are provided on the electrodes 0 and 111, and alignment films 114 and 115 for aligning the liquid crystal in a certain direction are formed on the electrodes 112 and 113. As the alignment film, an organic alignment film obtained by rubbing an organic polymer thin film such as polyimide or nylon with a cloth to perform rubbing treatment is most widely used. Such an alignment film is provided on both substrates or only on one substrate. In FIG. 1, a groove 117 for arranging liquid crystal molecules in a uniform direction of the alignment film subjected to the rubbing treatment is schematically described. This substrate is kept at a predetermined interval via a spacer having a constant diameter and is fixed by a seal portion 116.

The liquid crystal 118 is filled between the substrates and the electrodes are connected to an external signal to operate the liquid crystal. Whether the ferroelectric liquid crystal exhibits an ON state or an OFF state is uniquely determined because the spontaneous polarization direction of the liquid crystal is antiparallel to the direction of the applied electric field. Therefore, generally, the two states represented by the ferroelectric liquid crystal are energetically equivalent, and a high speed response can be achieved by switching from one to the other. The time is about 1 to 200 μsec, which is about three orders of magnitude faster than that of the nematic liquid crystal described above.

Further, the direction of spontaneous polarization of the ferroelectric liquid crystal selected by the electric field can be kept unchanged even after the electric field is removed. This is called having a memory property. Since it is a liquid crystal having such characteristics, it is possible to perform high-performance display with a simple matrix display sandwiched between substrates having a transparent electrode patterned, and further display metal-insulating film-metal ( MI
M) and a thin film transistor (also referred to as TFT) may be provided for higher-level display.

[0008]

[Problems to be Solved by the Invention] As described above,
The direction of spontaneous polarization of the ferroelectric liquid crystal is determined by the direction of the electric field applied from the outside, and its state is maintained even after the electric field is removed. That is, the spontaneous polarization of the liquid crystal is always directed toward either the upper or lower electrode. Furthermore, since the spontaneous polarization is an electric charge, a potential difference is always generated between the electrodes.

However, in actuality, various phenomena occur which reduce the potential difference generated between the electrodes and cause instability. One of them is a counter electric field due to polarization of the organic alignment film.

FIG. 2 shows the current of a ferroelectric liquid crystal display.
The voltage characteristics are shown. In this measurement, an electrode and an organic alignment film on the electrode were formed on a pair of insulating inner surfaces, and ± 20 V and 5 Hz triangular waves were applied to a liquid crystal cell in which a ferroelectric liquid crystal was sandwiched. According to FIG. 2, two types of peaks are measured as the signal is applied. The first peak 100 is a current flowing when the spontaneous polarization of the liquid crystal is inverted according to the applied signal, and is a characteristic characteristic of the ferroelectric liquid crystal. Calculate the amount of charge from this peak area and calculate half of it,
Further, the value converted per unit area is usually used as the value of spontaneous polarization.

The second peak 101 is generated next, which is generated near the point where the inversion of the spontaneous polarization of the liquid crystal is about to end. This is the extra current associated with the above-mentioned anti-electric field, which delays the saturation of the optical response, and the position of the first peak changes depending on the size of the second peak so as to reduce the memory property. Was causing a decrease in the contrast ratio. Furthermore, when an electric field is applied to the liquid crystal to invert the liquid crystal, it is necessary to invert not only the liquid crystal but also the anti-electric field, resulting in a slow response speed.

Further, in the driving by the thin film transistor,
Since only a fixed amount of electric charge for switching the liquid crystal is supplied in an extremely short time, a high contrast ratio cannot be obtained unless the liquid crystal is sufficiently switched by the supplied electric charge amount. For that purpose, it is important to reduce how much the supplied charge is consumed in addition to the liquid crystal inversion. However, in the related art, the extra charge was consumed by the anti-electric field, so that the liquid crystal inversion was insufficient and the contrast ratio was lowered. Furthermore, in order to sufficiently invert such a liquid crystal, it is necessary to supply a large amount of charges, and it is necessary to use an expensive and high-performance thin film transistor that can carry a large current, which increases power consumption and costs. Was causing an improvement. In addition, the time required to supply the electric charge is lengthened and the speed is reduced. Therefore, it has been desired to reduce the extra charge consumption that appears as the second peak.

In order to solve these problems, it is attempted to eliminate the influence of the anti-electric field on the liquid crystal by thinning the alignment film or inserting an inorganic film having a high dielectric constant between the alignment film and the electrode. Attempts have been made to do so, but they did not make a significant improvement.

The present invention provides a high-performance liquid crystal electro-optical device which eliminates the occurrence and influence of a counter electric field when driving a ferroelectric liquid crystal.

[0015]

As a constitution for solving the above problems, the first invention of the present invention is a liquid crystal having a smectic liquid crystal passing through a nematic phase between a pair of insulating substrates facing each other. The electro-optical device is a liquid crystal electro-optical device characterized in that it has an electrode subjected to a rubbing treatment on the inner surface of each of the pair of substrates.

A second invention is a liquid crystal electro-optical device having a smectic liquid crystal passing through a nematic phase between a pair of insulating substrates facing each other, wherein rubbing is performed on the inner surface of each of the pair of substrates. A liquid crystal electro-optical device having a treated electrode having a coupling agent on its surface.

A third invention is a liquid crystal electro-optical device having a smectic liquid crystal passing through a nematic phase between a pair of insulating substrates facing each other, wherein an inner surface of one of the pair of substrates. Has an electrode and a rubbing-treated alignment film on the electrode, and the inner surface of the other substrate has a rubbing-treated electrode.

A fourth invention is a liquid crystal electro-optical device having a smectic liquid crystal passing through a nematic phase between a pair of insulating substrates facing each other, wherein an electrode is provided on each inner surface of the pair of substrates. And a liquid crystal electro-optical device having a rubbing-processed insulating inorganic film on the electrode.

According to the present invention, in each of the above-mentioned constitutions, the electrode of one of the pair of substrates is composed of a plurality of pixel electrodes, and each pixel electrode is connected to a thin film transistor. It is an electro-optical device.

The present invention uses a smectic liquid crystal that passes through a nematic phase and directly rubs the electrode or the insulating inorganic film on the electrode without using an organic alignment film such as polyimide, which has been conventionally indispensable. The above problem is solved by using only one substrate side.

[0021]

FIG. 3 conceptually shows the first invention, which is the most basic configuration of the present invention. As shown in FIG. 3, rubbing treatment is performed directly on the electrodes 122 and 123 of the insulating substrates 120 and 121, and a smectic liquid crystal passing through a nematic phase is sandwiched between the substrates.

When manufacturing a display which is less affected by the anti-electric field in a ferroelectric liquid crystal display, a method is usually used in which the thickness of the organic alignment film such as polyimide is reduced to reduce the effect of the film. However, due to the existence of the alignment film, the adverse effect of the counter electric field was inevitably generated. This is because the alignment film was indispensable for aligning the liquid crystal.

However, the inventors of the present invention can directly manufacture a liquid crystal electro-optical device having a good alignment state and no influence of a counter electric field by rubbing the electrode without using an alignment film. I have found

The current-voltage characteristics of the liquid crystal electro-optical device of the present invention are shown in FIG. 4, but as shown in the figure, there is almost no second peak due to the anti-electric field. 2 in the current direction
The region in which the first peaks overlap with each other is extremely small, which shows that it has a good memory property.

The problem here is whether or not the liquid crystal can be well aligned without the organic alignment film such as polyimide. The first important point here is the selection of the liquid crystal phase sequence. In the present invention, it is necessary to select a phase-series liquid crystal that passes through a nematic phase having good orientation next to the isotropic phase in the high temperature portion. That is, directly from the isotropic phase,
It is preferable that the major axis of the molecule is aligned with the orientation axis direction and that a nematic phase that does not form a layered structure is passed through. This nematic phase is synonymous with the cholesteric phase and exhibits the behavior of the nematic phase in the surface-stabilized state. A material in which a highly ordered phase such as a smectic A phase or a smectic C ^* directly comes from the isotropic phase is not desirable. Such a liquid crystal provides a certain degree of orientation of the liquid crystal molecules, but does not provide good alignment.

Further, the strength when rubbing the electrode is better than the normal rubbing density.
The rubbing density R can usually be expressed by the following equation. R = n (M × d × π ± V) / V n: number of times, M: roll rotation number (times / second), d: roll diameter (mm) V: table moving speed (mm / second) TN liquid crystal In the case of the liquid crystal electro-optical device used, R is 100 to
300, and 200 to 1 for a high pretilt angle alignment film.
It is usually 000. In the case of the present invention, a rubbing density of 200 to 20000 seems to be good. Ferroelectric liquid crystal having a nematic phase exhibits good alignment in a display in which such treatment is applied to the electrodes. The same applies to nematic liquid crystals. Usually, in a soft organic alignment film such as a polyimide film, if the rubbing density is too high, the alignment film may peel off, but this is not the case in the present invention because there is no alignment film itself.

In addition, for example, IT which is a translucent electrode is used as the electrode.
When rubbing was directly performed using O and the electrode surface was observed with an electron microscope, ITO crystal grains were 50 to 10
It was only observed at a size of 00Å, and scratches and deposits showing a uniform directionality due to rubbing could not be recognized.

Further, when the surface of the substrate is measured by photoelectron spectroscopy (ESCA), an increase in the amount of carbon can be observed when the rubbing treatment is performed, so that it is considered that the fiber component of the rubbing cloth is transferred in some form. In FIG. 3, it is shown as a schematic groove 125. However, there are still many unknowns as to what causes liquid crystal to be aligned. Therefore, only the fact that it exhibits a good orientation is presented here.

Next, the second invention will be described. Apply a layer of coupling agent on the electrode surface by coating,
When this electrode is subjected to a rubbing treatment and a smectic liquid crystal that passes through a nematic phase is sandwiched between the substrates, the coupling agent usually has hydrophobicity, and the liquid crystal molecules tend to be vertically aligned on it. When this is further rubbed, a component for orienting the liquid crystal molecules in parallel is provided on the substrate surface, and the liquid crystal molecules are in a state of having a certain pretilt angle (angle of the liquid crystal molecules with respect to the substrate surface). The pretilt angle at this time is 1 to 10 °. Only one molecule of the coupling agent is adsorbed on the substrate, and the layer has only a very small insulation resistance, so that no anti-electric field is generated and good orientation and characteristics are exhibited.

Next, the third invention will be described. On the inner surface of one of the substrates, an electrode and a general alignment film that has been subjected to a rubbing treatment on the electrode are provided, and on the inner surface of the other substrate,
The electrodes are rubbed without forming an alignment film.
That is, the organic alignment film is provided only on the electrode on one substrate side.

When the organic alignment films are formed on both substrates, the influence of the counter electric field is very likely to occur due to the insulating properties of the alignment films. If the alignment film is formed only on one side, the effect is naturally small, but in that case, it was very difficult to align the liquid crystal that passes through the nematic phase. The reason for this is that the liquid crystal has a property as a cholesteric liquid crystal when it is in a nematic phase, so that the liquid crystal molecules have a property of swirling in the direction of the distance between the substrates. I can't get it. In order to improve this property, it was necessary to give the two substrate surfaces both orientations.

Therefore, when the rubbing treatment is applied to the electrode surface without the alignment film as in the present invention, the uniaxial orientation is good,
Moreover, the influence of the anti-electric field could be reduced. In addition, by providing a layer of a coupling agent on the electrode surface without an alignment film and performing a rubbing treatment, the pretilt angles of liquid crystal molecules on both substrates could be aligned.

Next, the fourth invention will be described. Forming an insulative inorganic film on an electrode has another characteristic different from those described above. Many insulating inorganic films have a high dielectric constant, and by forming an inorganic film having a high dielectric constant on an electrode, the anti-electric field becomes extremely small and adverse effects on liquid crystal switching can be eliminated. The dielectric constant at which the effect is sufficiently obtained is 8 or more, which is 3 to 4 times that of an organic alignment film such as polyimide, and as an inorganic film having that value, alumina,
Examples include titanium oxide, tantalum oxide, tungsten oxide, barium titanate, and silicate glass containing titanium oxide. Further, the insulating inorganic film is harder than the organic film and is excellent in insulating property, so that it serves as a short-circuit preventing film of a liquid crystal display.

In the conventional liquid crystal electro-optical device which requires an organic alignment film on the inorganic film provided on the electrodes, it was difficult to avoid the influence of the anti-electric field due to the alignment film. By forming an inorganic film on the electrode without forming an alignment film and subjecting it to a rubbing treatment, a good uniaxial alignment was exhibited, and the influence of the counter electric field could be removed.

With the structure of the present invention as described above, the influence of the anti-electric field due to the alignment film, which has been a problem in the past, is removed to prevent the occurrence of the second peak, the memory property is improved, and the high speed and high contrast ratio is achieved. We were able to.

In each of the above configurations, in the thin film transistor drive type liquid crystal electro-optical device in which the electrode of one substrate is a plurality of pixel electrodes and the switching of each pixel is performed by the thin film transistor, It is possible to eliminate unnecessary consumption due to a large amount of anti-electric field, and as a result, the liquid crystal between the electrodes can be sufficiently inverted even with a small charge supply amount of an inexpensive TFT, and the contrast ratio can be improved.
We were able to bring about higher speeds, lower power consumption, and lower costs. Examples will be shown below.

[0037]

【Example】

 [Example 1]

In this embodiment, a liquid crystal electro-optical device in which an electrode is directly rubbed will be described. First, a monitor experiment was conducted to see the effect of the invention. Including comparative examples, experimental cells having the following four types of structures on both substrates were prepared and measured. Parallel rubbing of ITO (Indium-Tin-Oxide) cell of the present invention (rubbing direction is parallel on both substrates) Cell Toray polyimide LP-64 (200Å) on ITO
Parallel rubbing cell of ITO Silicon Chemicals A2014 on ITO (300
Å) and Toray's polyimide LP-64 (200 Å) laminated parallel rubbing cell Nissan Polyimide RN305 on ITO (LP-
(200 Å) parallel rubbing cell with dielectric constant higher than 64

In all of the cells 1 to 3, a pair of translucent electrodes having an area of 26 mm ² are provided inside a blue glass substrate which is a pair of translucent insulating substrates, and 100% ITO is formed by DC sputtering.
Formed to a thickness of 0Å. The sheet resistance was 20Ω / □. In the cell of No. 3, an alignment film, or a silicon oxide film and an alignment film are formed on ITO, and each film is spin-coated for 20 seconds at a rotation speed of 4000.
After coating at rpm, baking was performed at 280 ° C. for 2.5 hours.

Next, the upper surfaces of the electrodes and the alignment film were rubbed. The rubbing device has a roll diameter of 130 mm, a rotation speed of 900 rpm, a table moving speed of 20 mm / sec, and a rubbing frequency of once. Charge Non (made by Asahi Kasei) was used as a rubbing cloth. The rubbing density was about 300.

After that, the distance between the substrates (here, the thickness of the liquid crystal layer) is set to 1.5 μm by the spacer and the sealing material of epoxy resin.
The m was fixed so that the rubbing directions on both substrates were parallel to each other. CS1014 manufactured by Chisso was injected as a liquid crystal material. The phase series was an isotropic phase-nematic phase-smectic A phase-smectic C ^* phase, and the magnitude of spontaneous polarization at room temperature was about 6 nC / cm ² .

First, in order to measure the second peak of each cell, a resistor of 100 KΩ is connected in series to the pixel capacitance of each cell, a triangular wave of ± 30 V and 5 Hz is applied, and the voltage at the resistance end is measured by an oscilloscope. Thus, the current value of the second peak was obtained in each cell.

Next, each cell has ± 20 V and a pulse width of 200 μ.
A pulse signal of 2 seconds was applied at a pulse interval of 50 ms to measure the contrast ratio, and the memory property as a simple matrix type liquid crystal electro-optical device was measured.

Next, a state in which an FET was connected to these cells and driven to drive a TFT was simulated, and the residual voltage and the contrast ratio were measured. Fig. 5 (A) shows the measurement system of the residual voltage and the contrast ratio, and Fig. 5 shows the signal waveform at each location.
It shows in (B). In FIG. 5A, a driving signal is input to the source portion 151 of the thin film transistor, and the source signal 156 (see FIG. 5) is supplied to the pixel only when the gate 152 is selected.
(B)) enters. When the gate is off, the resistance between the source and drain 153 is very high, and the charges injected into the pixel capacitor 155 cannot escape through the transistor. In this case, the potential, that is, the residual voltage decreases only when the charge is consumed inside the pixel capacitor (FIG. 5B 159). If it is not consumed, the electric charge is retained and the potential is not attenuated (Fig. 5 (B) 15).
8). It goes without saying that the desirable characteristic is that the pixel potential is kept constant without being attenuated. This potential is measured by the voltmeter 154.

The applied voltage is ± 14 V, the gate ON time is 1 μsec, and the contrast measurement is
The contrast ratio and the residual voltage of the pixel were measured 1 second after the gate was turned on.

The results of the above measurements are shown in Table 1. The second
The height of the peak is indicated by a value obtained by subtracting the current value due to the capacitance and the resistance component from the current value at the apex of the second peak.

[0047]

[Table 1]

As shown in Table 1, the smaller the second peak, the better the contrast ratio by pulse application, the contrast ratio during FET driving and the residual voltage tended to be. And, the current-voltage characteristics of the parallel rubbing cell of the present invention, which is made only of ITO, are as shown in FIG.
The peak hardly occurred, and the cell of the present invention showed the best characteristics in all the measured items among the four measured cells. On the other hand, the second peak was observed in all the other three cells, and none of the measurement results were as good as those of the cell of the present invention. From these results, the structure of the present invention prevents the consumption of extra charges due to the anti-electric field even in a simple matrix type and a TFT driving type liquid crystal electro-optical device, and has a high memory property, a high contrast ratio, a high speed,
It has been found that the liquid crystal electro-optical device can have low power consumption and low cost.

Based on this result, a liquid crystal electro-optical device having the constitution of the present invention was manufactured. It will be described with reference to FIG.
Sodium lime glass 120, 121 was used as an insulating substrate, and ITO was formed thereon as a transparent electrode by a DC sputtering method or an electron beam evaporation method. The membrane pressure was 500 to 1200Å here, 1000Å, and the sheet resistance was 10 to 200 Ω / □, here 20 Ω / □. This was processed into a matrix-shaped electrode pattern by an ordinary photolithography method.

Next, this electrode was rubbed. The rubbing device has a roll diameter of 130 mm and a rotation speed of 900 rp.
m, table moving speed 20 mm / sec, rubbing frequency 1
It was once. As the rubbing cloth, there are cotton, rayon, nylon velvet cloth, Chargenon (made by Asahi Kasei), etc. We used Chargenon here. The rubbing density was about 300. Epoxy resin is printed as the sealant 124 on one of the substrates, and 1. is printed on the other substrate.
Spacers (not shown) having a size of 5 to 2.5 μm were dispersed, and a predetermined interval, which was determined by the spacers as a parallel cell, was set to 1.5 μm in this case and fixed so that the rubbing directions on both substrates were parallel. As the liquid crystal material 126, CS1014 manufactured by Chisso was used as in the experimental cell.

Observation of the alignment state of the display under a polarizing microscope showed a good extinction position in the nematic phase and the smectic A phase. In the smectic C ^* phase, a normal zigzag defect and domains in two states could be observed. The device, which was completed by attaching a polarizing plate and peripheral circuits, showed high memory performance, fast response speed, and high performance.

In addition, TF is applied to a plurality of pixels on the surface of one substrate.
A TFT drive type liquid crystal electro-optical device connected with T was manufactured by rubbing the electrodes without forming an alignment film as in the simple matrix type. As a result, an excellent device with a high contrast ratio was obtained. It was possible to achieve high speed, low power consumption, and low cost.

As described above, the liquid crystal electro-optical device for directly rubbing the transparent electrode of the present invention is superior to the one using the conventional alignment film regardless of whether it is a simple matrix type or a TFT driving type. It could be a liquid crystal electro-optical device.

Example 2 An example of a liquid crystal electro-optical device using a coupling agent will be described. First, an experimental cell was prepared in the same manner as in Example 1. As a coupling agent, Surfine 150 manufactured by Dainippon Ink Co., Ltd.
%, And the soda-lime glass substrate on which the transparent electrode (ITO, 1000Å) was formed was immersed in the coupling agent solution for 1 minute. It is more effective to apply ultrasonic waves at this time. Place this substrate upright and remove excess solution, then
Heated at 20 ° C. for 30-60 minutes. The electrode surface was rubbed, and two substrates were stacked so that the rubbing directions coincided with each other to prepare an experimental cell having a substrate-to-substrate distance of 2.5 μm. The liquid crystal material CS1014 manufactured by Chisso was injected between the substrates, and the contrast ratio was measured with a polarizing microscope. In the measurement of the contrast ratio by pulse application (the same conditions as in Example 1), the contrast ratio was 12, and the memory property was good.

On the other hand, the contrast ratio in FFT driving of the same cell was about 33, and it was found that high performance can be obtained even when driving with a TFT. In both cases, the second peak did not occur in the voltage-current characteristics. Here, the pretilt angle was measured. ZLI2293 manufactured by Nematic Liquid Crystal Merck was injected into the cell instead of the above liquid crystal material, and the pretilt angle was measured by the crystal rotation method. The pretilt angle was about 5 °. Since the simple matrix type and the TFT driving type liquid crystal electro-optical device were manufactured by the constitution of this example, both devices could be made extremely high-performance devices like the experimental cells.

Example 3 First, an experimental cell was prepared for conducting a monitor experiment. Toray LP-64 applied as an organic alignment film on one inner surface of the ITO-attached substrate is applied.
A rubbing treatment was performed using a 0Å thick alignment film. Two types of substrates were prepared as the other substrate: one with the ITO substrate facing the substrate without any particular treatment, and one with the rubbing substrate with the ITO substrate facing the substrate. The distance between the substrates was 2.5 μm, and the liquid crystal used was CS1014 manufactured by Chisso.

In the cell without rubbing treatment on ITO, the uniaxial orientation of liquid crystal molecules was poor and it could not be said that the orientation was good. In the memory property measurement by pulse application similar to that in Example 1, the contrast ratio was 4, and in the measurement by the FET drive, the contrast ratio was 6. Meanwhile IT
The cell of the present invention which was rubbed even on O had a good uniaxial orientation, and the contrast ratio was 18 in pulse application measurement under the same conditions as in Example 1 and about 35 in FET driving measurement. The liquid crystal electro-optical device of the simple matrix type and the TFT driving type having the structure of this example was manufactured, and thus it was possible to obtain an extremely high-performance device similar to the experimental cell.

[Example 4] AT902 manufactured by Nissan Kagaku Co., Ltd. was applied onto two substrates with ITO by a spin coating method or an offset method and baked at 300 ° C to form a silicon oxide film of about 300 Å as an insulating inorganic film. Formed as. The dielectric constant of this film is about 2
It is 0. The surface of this film is rubbed and laminated so that the rubbing directions are parallel, and the substrate spacing is 2.5 μm.
The experimental cell of was produced. This is CS1014 made by Chisso
Was injected and the contrast ratio was measured.

The contrast ratio was 14 in the measurement by pulse application. The contrast ratio was about 30 when measured by driving the FET. When observed under a microscope, it was found to be well uniaxially oriented. The pretilt angle was about 0.8 °. The second peak was not observed even when the current-voltage characteristics were evaluated. When a simple matrix type and a TFT driving type liquid crystal electro-optical device were manufactured with this configuration, good characteristics were obtained as in the experiment.

[0060]

As described above, according to the present invention, it is possible to prevent excessive charge consumption due to the anti-electric field, and to realize a good memory property, a high contrast ratio and a high-speed display. Further, when the present invention is applied to a liquid crystal cell provided with a thin film transistor and driven, a high-performance display with high speed, high contrast ratio, low power consumption, and low cost can be realized.

[Brief description of drawings]

FIG. 1 shows a structure of a conventional liquid crystal cell.

FIG. 2 shows current-voltage characteristics of a conventional liquid crystal cell.

FIG. 3 shows an example of the structure of the liquid crystal cell of the present invention.

FIG. 4 shows a measurement example of current-voltage characteristics of the liquid crystal cell of the present invention.

FIG. 5 shows a measurement example of driving a thin film transistor.

[Explanation of symbols]

 100 First Peak 101 Second Peak 120, 121 Insulating Substrate 122, 123 Electrode 124 Sealing Material 125 Schematic Groove Representing State after Rubbing Treatment 126 Liquid Crystal

Claims (8)

[Claims] 1. A liquid crystal electro-optical device having a smectic liquid crystal passing through a nematic phase between a pair of insulating substrates facing each other, wherein the inner surface of each of the pair of substrates is rubbed. A liquid crystal electro-optical device having an electrode. 2. The liquid crystal electro-optical device according to claim 1, wherein an electrode of one of the pair of substrates is composed of a plurality of pixel electrodes, and each pixel electrode is connected to a thin film transistor. . 3. A liquid crystal electro-optical device having a smectic liquid crystal that passes through a nematic phase between a pair of insulating substrates facing each other, wherein the inner surface of each of the pair of substrates is rubbed. And a liquid crystal electro-optical device having an electrode having a coupling agent on its surface. 4. The liquid crystal electro-optical device according to claim 3, wherein an electrode of one of the pair of substrates is composed of a plurality of pixel electrodes, and each pixel electrode is connected to a thin film transistor. . 5. A liquid crystal electro-optical device having a smectic liquid crystal that passes through a nematic phase between a pair of insulating substrates facing each other, wherein an electrode is provided on the inner surface of one of the pair of substrates. And a rubbing-treated alignment film on the electrode, and a rubbing-treated electrode on the inner surface of the other substrate. 6. The liquid crystal electro-optical device according to claim 5, wherein an electrode of one of the pair of substrates is composed of a plurality of pixel electrodes, and each pixel electrode is connected to a thin film transistor. . 7. A liquid crystal electro-optical device having a smectic liquid crystal passing through a nematic phase between a pair of insulating substrates facing each other, wherein an electrode and an electrode on the inner surface of each of the pair of substrates. 2. A liquid crystal electro-optical device having an insulating inorganic film that has been subjected to the rubbing treatment of. 8. The liquid crystal electro-optical device according to claim 7, wherein an electrode of one of the pair of substrates is composed of a plurality of pixel electrodes, and each pixel electrode is connected to a thin film transistor. .