JP2612504B2 - Liquid crystal device - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a liquid crystal device using a ferroelectric liquid crystal capable of distinguishing contrast depending on the direction of an electric field.

[Prior Art] The use of a bistable liquid crystal device has been
k) and Lagerwall, both of which are proposed in JP-A-56-107216 and U.S. Pat. No. 4,367,924. In general, a ferroelectric liquid crystal having a chiral smectic C phase (SmC ^* ) or an H phase (SmH ^* ) is used as the bistable liquid crystal. In these states, the first optical element responds to an applied electric field. One of the optically stable state and the second optically stable state, and has the property of maintaining the state when no electric field is applied, that is, it has bistability, and has a quick response to a change in the electric field. so,
It is expected to be widely used in fields such as high-speed and storage type display devices.

In the case of a matrix display device in which stripe electrode groups are provided inside a pair of substrates used in the ferroelectric liquid crystal element and the stripe electrodes are wired so as to be perpendicular to each other, for example, Japanese Patent Laid-Open No. -193426, 59-193427, 60-156046 and 60-156
The driving method disclosed in, for example, Japanese Patent No. 047 can be applied.

FIG. 2 shows an example of the driving waveform, and shows a method of providing two types of periods of a “black” erasing phase and a selective “white” writing phase within a selection period on one scanning line. In the erasing phase, a positive voltage is applied to the scanning electrode to bring all or predetermined pixels on the scanning line into a first stable state (hereinafter referred to as a "black" erasing state). On the other hand, during the period, a negative voltage is applied to the scanning electrode to reverse the pixel to a second stable state (hereinafter referred to as a “white” state) (selected pixel).
, A positive voltage is selectively applied only to the information electrodes corresponding to, and a negative voltage is applied to the information electrodes corresponding to the other pixels (half-selected pixels). As a result, an inversion electric field that is equal to or greater than the threshold value for the selected pixel and equal to or less than the threshold value for the half-selected pixel is generated, “white” is written to the selected pixel, and the half-selected pixel maintains the “black” state. At this time, the absolute values of the voltage values of the erase phase and the write phase applied are usually equal.

By the way, in a method of rubbing a polymer film such as polyimide or polyvinyl alcohol having a relatively low pretilt angle, which is most commonly used as a method for controlling the orientation of a ferroelectric liquid crystal, the apparent tilt angle θ is usually a true value. Two bistable alignment states (splay alignment) which are about half smaller than the tilt angle Θ are emphasized.

In other words, an alignment film such as LP64 (manufactured by Toray Industries, Inc.) with a relatively low pretilt is coated on a substrate and rubbed.
The upper and lower two rubbing directions are the same and the gap is maintained at about 1.5 μm to form a cell, and a ferroelectric liquid crystal such as CS1014 (manufactured by Chisso) is injected into the cell to lower the temperature. And the process shown in FIGS. 3 (a) to 3 (e). That is, in the state shown in FIG. 3A immediately after the transition from the high-temperature phase to the Sc ^* phase, the alignment states (C1 alignment state) 21 and 22 having a low contrast are taken, and the temperature is lowered. As shown in FIG. 2B, zigzag defects 23 are generated, and alignment states (C2 alignment states) 24 and 25 having high contrast appear from the defect. As the temperature further lowers, the C2 orientation state expands (FIGS. (C) and (d)), and finally the whole becomes the C2 orientation state (FIG. (E)).

The two types of orientation states, C1 and C2, are explained by the difference in the Sheplon structure of the smectic layer as shown in FIG. In FIG. 4, 31 indicates a smectic layer, 32 indicates a C1-oriented region, and 33 indicates a C2-oriented region. Smectic liquid crystal generally has having a layer structure bent broken in the middle of the layer upper and lower substrates as in the fourth diagram Since S _C phase or S _C ^* layer spacing when transition to phase shrinks from S _A phase structure (chevron structure) Take. There are two bending directions, C1 and C2, as shown in the figure. As is well known, the liquid crystal molecules at the substrate interface form an angle with the substrate by rubbing (pretilt), and the direction is the rubbing direction. The liquid crystal molecules are leaning toward the head (the tip is floating). Because of this pretilt, C1 orientation and C2 orientation are not equivalent in elastic energy,
Transition occurs at certain temperatures as described above. In addition, transition may occur due to mechanical strain. Looking at the layer structure of FIG. 4 in a plan view, the boundary 34 when shifting from the C1 orientation to the C2 orientation in the rubbing direction is called a lightning defect in a zigzag lightning shape, and the environment 35 when shifting from C2 to C1. Is called a hairpin defect with a wide, gentle curve. Conventionally,
An object of the present invention is to provide a liquid crystal element using the alignment state of C2 from the viewpoint of contrast in the alignment of C1 and C2.

For example, when multiplexing drive using a drive waveform as shown in FIG. 2 is applied to an element showing this alignment state, a sufficient drive margin can be secured, but the contrast is still not sufficient and there is room for improvement. there were.

[Problems to be Solved by the Invention] Accordingly, an object of the present invention is to provide a display element that is brighter and has a higher contrast than in the related art in view of the problems of the related art. In view of the above, an object of the present invention is to provide a liquid crystal device having a unit capable of performing a display with high contrast and transmittance while securing a sufficient driving margin for the liquid crystal element having a uniform orientation. .

Means and Solution for Solving the Problems Accordingly, the present invention provides a pair of substrates having a scanning electrode group and an information electrode group, each of which has been subjected to a uniaxial orientation treatment, and a ferroelectric substance disposed between the substrates. A liquid crystal element having a liquid crystal;
A scan formed from two phases of an erasing phase and a writing phase having different polarities, wherein the absolute value of the voltage value applied to the pixel in the erasing phase is larger than the absolute value of the voltage value applied to the pixel in the writing phase And a means for applying a signal to the scanning electrode group, wherein the liquid crystal element has a pretilt angle α of the ferroelectric liquid crystal, a tilt angle Θ, and a tilt of the chiral smectic layer of the ferroelectric liquid crystal with respect to the substrate normal. Assuming that the angle is δ, the ferroelectric liquid crystal has an alignment state represented by Θ <α + δ, and the ferroelectric liquid crystal in the alignment state shows at least two stable states, and the angle formed by their optical axes. 1/2 theta _a and the tilt angle theta of the ferroelectric liquid crystal is is to have an orientation state represented by Θ> θ _a> Θ / 2 in.

Alternatively, in the liquid crystal element, if the pretilt angle of the ferroelectric liquid crystal is α, the tilt angle is Θ, and the tilt angle of the chiral smectic layer of the ferroelectric liquid crystal with respect to the substrate normal is δ, the ferroelectric liquid crystal can be expressed as Θ <α + δ And the ferroelectric liquid crystal in the alignment state shows at least two stable states, and aligns the absorption axis of one of the polarizing plates at a position that bisects the angle between their optical axes. From the arrangement in which the absorption axis of the other polarizer is aligned perpendicularly to the other polarizer, only one
The color of the first stable state when rotated by 30 ° is the same as the color of the second stable state when rotated counterclockwise by the same angle.

Alternatively, in the liquid crystal element, if the pretilt angle of the ferroelectric liquid crystal is α, the tilt angle is Θ, and the tilt angle of the chiral smectic layer of the ferroelectric liquid crystal with respect to the substrate normal is δ, the ferroelectric liquid crystal can be expressed as Θ <α + δ And the ferroelectric liquid crystal in the alignment state has two stable states with low transmittance at the extinction position under crossed Nicols, and one with high transmittance at the extinction position under crossed Nicols or It has a total of three or four states of two stable states. In this case, the first and second stable states where the ferroelectric liquid crystal has low transmittance at the extinction position under crossed Nicols, and the third and fourth stable states having high transmittance at the extinction position under crossed Nicols. The four stable states of the stable state are shown. The absorption axis of one of the polarizing plates is aligned with a position at which the angle between the optical axes is divided into two, and the absorption axis of the other polarizing plate is aligned perpendicularly to the one. The color that the first stable state exhibits when only the polarizing plate is rotated clockwise by 3 ° to 30 ° is the same as the color that the second stable state exhibits when rotated counterclockwise by the same angle. Yes, the color in the third stable state when only one of the polarizers is rotated clockwise by 3 ° to 30 °, and the color in the fourth stable state when rotated by the same angle in the counterclockwise direction May be different.

Alternatively, in the liquid crystal element, the direction of the uniaxial alignment treatment is the same direction, and the main alignment state of the ferroelectric liquid crystal is surrounded by hairpin defects and lightning defects by foreign substances between the substrates or by applying strain to the substrates. Another alignment state is generated, and this alignment state is surrounded by these defects that occur in the order of lightening defects and hairpin defects along the direction in which the liquid crystal molecules float from the alignment film surface due to pretilt. in the alignment state, the ferroelectric liquid crystal exhibits at least two stable states, which is half of the angle between the optical axes thereof theta _a and ferroelectric liquid crystal tilt angle theta and the Θ> θ _a> Θ It may be represented by / 2.

Alternatively, in the liquid crystal element, the direction of the uniaxial alignment treatment is the same direction, and the main alignment state of the ferroelectric liquid crystal is surrounded by hairpin defects and lightning defects by foreign substances between the substrates or by applying strain to the substrates. Another alignment state is generated, and this alignment state is surrounded by these defects that occur in the order of lightening defects and hairpin defects along the direction in which the liquid crystal molecules float from the alignment film surface due to pretilt. In the aligned state, the ferroelectric liquid crystal shows at least two stable states, the absorption axis of one polarizing plate is aligned with the position at which the angle between the optical axes is bisected, and the absorption axis of the other polarizing plate is perpendicular to it. The color of the first stable state when only one polarizer is rotated clockwise by 3 ° to 30 ° from the alignment of the axes, and the color in the counterclockwise direction Flip color exhibited by the second stable state may be the same obtained while angular rotation.

Alternatively, in the liquid crystal element, the direction of the uniaxial alignment treatment is the same direction, and the main alignment state of the ferroelectric liquid crystal is surrounded by hairpin defects and lightning defects by foreign substances between the substrates or by applying strain to the substrates. Other alignment state, and this alignment state is surrounded by these defects that occur in the order of lightning defects and hairpin defects along the direction in which the liquid crystal molecules float from the alignment film surface due to pretilt, and The ferroelectric liquid crystal in the main alignment state has a total of three or four states, that is, two stable states under crossed Nicols and low transmittance at the extinction position and one or two stable states under crossed Nicols and high transmittance at the extinction position. May be provided. In this case, the ferroelectric liquid crystal has the first and second stable states with low transmittance at the extinction position under crossed Nicols, and the third and fourth two states with high transmittance at the extinction position under crossed Nicols. Shows the four stable states of the two stable states, with the absorption axis of one of the polarizing plates aligned at a position that bisects the angle between the optical axes, and the absorption axis of the other polarizing plate aligned perpendicular to it. The color of the first stable state when only one polarizer is rotated clockwise by 3 ° to 30 ° is the same as the color of the second stable state when rotated counterclockwise by the same angle. And a color in the third stable state when only one of the polarizing plates is rotated clockwise by 3 ° to 30 °, and a color in the fourth stable state when rotated by the same angle in the counterclockwise direction. The colors may be different.

Alternatively, in the liquid crystal element, the direction of the uniaxial alignment treatment is the same direction, and the main alignment state of the ferroelectric liquid crystal is surrounded by hairpin defects and lightning defects by foreign substances between the substrates or by applying strain to the substrates. Another alignment state is created, which is surrounded by these defects that occur in the order of lightening defects and hairpin defects with respect to the uniaxial alignment processing direction, and at least two ferroelectric liquid crystals in the main alignment state. Θ _a which is one-half of the angle between their optical axes
And the tilt angle の of the ferroelectric liquid crystal may be expressed as Θ> θ _a > Θ / 2.

Alternatively, in the liquid crystal element, the direction of the uniaxial alignment treatment is the same direction, and the main alignment state of the ferroelectric liquid crystal is surrounded by hairpin defects and lightning defects by foreign substances between the substrates or by applying strain to the substrates. This alignment state is surrounded by these defects that occur in the order of lightening defects and hairpin defects with respect to the uniaxial alignment processing direction, and the ferroelectric liquid crystal in the main alignment state is At least two stable states are shown, and the absorption axis of one of the polarizing plates is aligned at a position bisecting the angle formed by the optical axes, and the polarization axis of one of the polarizing plates is adjusted perpendicularly to the absorption axis of the other polarizing plate. The color of the first stable state when only the plate is rotated clockwise by 3 ° to 30 °, and the second stable state when the plate is rotated counterclockwise by the same angle Color exhibited by the may be the same.

Alternatively, in the liquid crystal element, the direction of the uniaxial alignment treatment is the same direction, and the main alignment state of the ferroelectric liquid crystal is surrounded by hairpin defects and lightning defects by foreign substances between the substrates or by applying strain to the substrates. This alignment state is surrounded by these defects that occur in the order of lightening defects and hairpin defects with respect to the uniaxial alignment processing direction, and the ferroelectric liquid crystal in the main alignment state is There may be a total of three or four states, that is, two stable states with low transmittance at the extinction position under crossed Nicols and one or two stable states with high transmittance at the extinction position under crossed Nicols. In this case, the first and second stable states where the ferroelectric liquid crystal has low transmittance at the extinction position under crossed Nicols, and the third and fourth stable states having high transmittance at the extinction position under crossed Nicols. It shows four stable states, and the angle between their optical axes is 2
When the absorption axis of one of the polarizing plates is aligned with the position where the light is equally divided, and only the one polarizing plate is rotated clockwise by 3 ° to 30 ° from the arrangement in which the absorption axis of the other polarizing plate is aligned perpendicularly thereto, The color presented by the first stable state is the same as the color presented by the second stable state when rotated by the same angle in the counterclockwise direction,
The color of the third stable state when only one of the polarizers is rotated clockwise by 3 ° to 30 ° is different from the color of the fourth stable state when rotated by the same angle in the counterclockwise direction. You may do so.

Alternatively, the liquid crystal element is composed of a ferroelectric liquid crystal and an alignment state of Sm.
In the process of lowering the temperature from the high temperature region showing the A phase to the temperature region showing the Sm ^* C phase, there is no alignment change accompanied by the occurrence of lightening defects and / or hairpin defects, and at least two stable ferroelectric liquid crystals in the alignment state shows a state, may be a theta _a and ferroelectric properties tilt angle of the liquid crystal theta is half the angle between the optical axes thereof are represented by _{Θ> θ a> Θ / 2} .

Alternatively, the liquid crystal element is composed of a ferroelectric liquid crystal and an alignment state of Sm.
In the process of lowering the temperature from the high temperature region showing the A phase to the temperature region showing the Sm ^* C phase, there is no alignment change accompanied by the occurrence of lightening defects and / or hairpin defects, and at least two stable ferroelectric liquid crystals in the alignment state In this state, the absorption axis of one of the polarizing plates is set to a position that bisects the angle between the optical axes, and only one of the polarizing plates is clocked from the arrangement in which the absorption axis of the other polarizing plate is aligned perpendicular to it. 3 ° to 30 ° in the direction
The color of the first stable state when rotated and the color of the second stable state when rotated counterclockwise by the same angle may be the same.

Alternatively, the liquid crystal element is composed of a ferroelectric liquid crystal and an alignment state of Sm.
In the process of lowering the temperature from the high temperature region showing the A phase to the temperature region showing the Sm ^* C phase, there is no alignment change accompanied by the occurrence of a lightning defect and / or a hairpin defect, and the ferroelectric liquid crystal in the alignment state is cross-Nicol, There may be a total of three or four states, two stable states with low transmittance in the extinction position and one or two stable states with high transmittance in the extinction position under crossed Nicols. In this case, the first and second stable states where the ferroelectric liquid crystal has low transmittance at the extinction position under crossed Nicols, and the third and fourth stable states having high transmittance at the extinction position under crossed Nicols. The four stable states of the stable state are shown. The absorption axis of one of the polarizing plates is aligned with a position at which the angle between the optical axes is divided into two, and the absorption axis of the other polarizing plate is aligned perpendicularly to the one. 3 ° to 30 ° clockwise
The color of the first stable state when rotated by the same angle as the color of the second stable state when rotated by the same angle in the counterclockwise direction is the same, and only one of the polarizing plates is rotated clockwise by 3 degrees.
The color of the third stable state when rotated by 30 ° to 30 ° may be different from the color of the fourth stable state when rotated by the same angle in the counterclockwise direction.

Alternatively, the liquid crystal element has a chiral smectic liquid crystal, and when the pretilt angle of the chiral smectic liquid crystal is α, the tilt angle is Θ, and the inclination angle of the chiral smectic layer with respect to the substrate normal is δ, the chiral smectic liquid crystal has the following formula: The chiral smectic liquid crystal having an alignment state represented by α + δ, and exhibiting at least two stable states in the alignment state, θa which is _a half of the angle between their optical axes, and the tilt angle Θ of the liquid crystal May have a relationship of Θ> θ _a > Θ / 2.

[Detailed Description of Embodiments of the Invention] FIG. 5 schematically depicts an example of the ferroelectric liquid crystal cell of the present invention.

11a and 11b are In ₂ O ₃ and ITO (Indium Tin Oxid
e) a substrate (glass plate) covered with transparent electrodes 12a and 12b, etc., on which insulating films 13a and 13b each having a thickness of 200 to 3000 mm
(SiO ₂ film, TiO ₂ film, Ta ₂ O ₅ film, etc.) and 50-1000 mm thick alignment control film 14a formed from polyimide, for example, obtained from a polyimide precursor having the structural unit shown in FIG.
And 14b are respectively laminated. Alignment control films 14a and 14
b indicates that the orientation directions are parallel and in the same direction (A in FIG. 1).
Rubbing process (arrow direction).
Between the substrates 11a and 11b, a ferroelectric smectic liquid crystal 15 is provided.
Is set, and the distance between the substrates 11a and 11b is set to a distance (for example, 0.1 to 3 μm) that is small enough to suppress the formation of a helical array structure of the ferroelectric smectic liquid crystal 15. The liquid crystal 15 has a bistable alignment state. The sufficiently small distances described above correspond to the substrates 11a and 11b.
And is held by a bead spacer 16 (silica beads, alumina beads) disposed between them. 17a and 17b are polarizing plates.

However, after that, the present inventors found that when a specific alignment film and liquid crystal combination were used, the above C1 → C2 transition was unlikely to occur, and no C2 alignment state was generated depending on the liquid crystal material. Low contrast 2 that was released
In addition to one stable state, we newly discovered that two other high-contrast stable states appear.

Therefore, if the whole screen is unified into the C1 orientation state as a display element and two states of high contrast in the C1 orientation are used as two states of black-and-white display, it is expected that a display with higher quality than before can be obtained. That is, the present inventors
The ferroelectric liquid crystal element is opposed to the ferroelectric liquid crystal while holding the ferroelectric liquid crystal therebetween, and electrodes for applying a voltage to the ferroelectric liquid crystal are formed on the opposing surfaces, respectively. And a pair of substrates which are substantially parallel to each other and have been subjected to uniaxial alignment processing in the same direction for aligning the ferroelectric liquid crystal. The pretilt angle of the ferroelectric liquid crystal is α, and the tilt angle (1 of cone angle) / 2) is Θ, and the inclination angle of the Sm ^* C layer is δ. If the ferroelectric liquid crystal has an alignment state represented by Θ <α + δ, four ferroelectric liquid crystals having a further chevron structure in the C1 alignment state are obtained. Confirmed that the state exists. The four C1 states are different from the conventional C1 state, and two of the four C1 states form a bistable state (uniform state). This uniform state of the C1 orientation has higher contrast than the conventionally used bistable state in the C2 orientation, and therefore,
By driving the liquid crystal in this uniform state, a large tilt angle θ is generated, a high-contrast image is displayed, and no afterimage is generated.

Hereinafter, the above will be described in detail. As shown in Table 1, the likelihood of the C1 → C2 transition is determined by the angle (pretilt angle) formed by the liquid crystal molecules near the substrate interface with the substrate, the tilt angle of the layer, and the tilt angle of the liquid crystal. Was dependent.

Table 1 shows three types of alignment films A to A having different pretilt angles.
This is a result of injecting three types of liquid crystals a to c having different tilt angles into the cell C and observing the alignment state. However, the alignment film of A is
LP64 (manufactured by Toray Industries, Inc.), the alignment film of B is SE610 (manufactured by Nissan Chemical Industries, Ltd.), and the alignment film of C is a polyimide obtained by firing polyamic acid having the structural formula shown in FIG. The angles were 2.5 °, 6 °, and 12 °, respectively. From Table 1, when the pretilt angle is large and the cone angle is small, C1
It can be seen that the orientation is maintained. This result can be understood by considering the following.

Since the directors near the substrate in the C1 orientation and the C2 orientation are on the cone 41 in FIGS. 6A and 6B, respectively, the tilt angle Θ, the pretilt angle α, and the layer inclination angle δ When Θ + δ> α (2) When C2 orientation, the relationship of Θ−δ> α (3) must be satisfied. Since the layer inclination angle δ has a value slightly smaller than the tilt layer Θ, the liquid crystal having a small tilt angle Θ has a small Θ−δ and a large pretilt angle α does not satisfy the relationship of the expression (3). No orientation appears. Therefore, C2 in the present invention
It is necessary that the condition for generating the C1 orientation without generating is that Θ−δ <α (4). Since the tilt angle and the layer tilt angle depend on the temperature of the liquid crystal, even if the formula (4) is satisfied at a certain temperature, the condition may be violated at a lower temperature and the C2 orientation may appear. The condition of equation (4) needs to be satisfied over the entire temperature range in which the liquid crystal is used as a display device.

In the present invention, the pretilt angle α is preferably 6 ° <
α <30 °, more preferably 8 ° <α <30 °, still more preferably 10 ° <α <30 °, Θ indicates 7 ° <α <27 °,
δ preferably indicates 0 <δ <25 °.

The following points will be described. In the conventional low pretilt alignment film, only two states having relatively low contrast can stably exist in the C1 alignment. However,
In a high pretilt alignment film such as the alignment film C shown in Table 1, there are four states in the C1 alignment, and two of them are in the same low contrast two states as in the prior art (under the visual field of a polarizing microscope). The liquid crystal direct is twisted between the upper and lower substrates because it has no extinction position and looks blue, and the other two are in a state where the contrast is high and the apparent tilt angle is large ( There is an extinction position under a polarizing microscope, which is hereinafter referred to as a uniform state). The contrast and transmittance of the newly found uniform state are higher than those in the C2 orientation.

In the uniform state of C1, the transmittance at the extinction position under cross Nicol is lower than that in the spray state of C1, and the spray state of C1 is indistinguishable between the two states, and only a total of three states of the uniform 2 state and the spray 1 state are observed. In some cases.

Table 2 shows the tilt angle theta _a ^Uniform and tilt angle Θ apparent in the tilt angle and theta _a ^splay uniform states apparent when no electric field in the splay state of some of the liquid crystal. The table also shows the ratio of θ _a ^splay , θ _a ^uniform and ^{示 し} . As can be seen from this table, even with the same liquid crystal material, the apparent tilt angle is small in the splay state and large in the uniform state. Θ _a ^splay in a splay state also look at the ratio of the Θ
/Θ<0.4, in uniform state, θ _a ^{uniform /}ユ ニ> 0.5
It is. Here, in the present invention, a state showing a relation of Θ> θ _a > を / 2 among the four states in the C1 state is referred to as a uniform state.

Therefore, the present invention provides a ferroelectric liquid crystal, and an electrode for applying a voltage to the ferroelectric liquid crystal is formed on the opposing surface while holding the ferroelectric liquid crystal therebetween, and the ferroelectric liquid crystal is formed. A pair of substrates which are substantially parallel to each other and have been subjected to a uniaxial alignment treatment in the same direction for aligning the ferroelectric liquid crystal, wherein the pretilt angle of the ferroelectric liquid crystal is α, the tilt angle is Θ,
Assuming that the inclination angle of the Sm ^* C layer is δ, the ferroelectric liquid crystal has an alignment state represented by Θ <α + δ, and the ferroelectric liquid crystal in the alignment state shows at least two stable states. trying to use to display the Yunifomu state in the C1 orientation satisfying the tilt angle theta of a half of the angle between the optical axis theta _a and ferroelectric liquid crystals Θ> θ _a> Θ / 2 in relation Things.

Further, the C1 state referred to in the present invention causes another alignment state surrounded by hairpin defects and lightning defects by applying a strain to a foreign substance such as a spacer in the cell or the cell, and the liquid crystal molecules from the alignment film surface due to pretilt. These lightning defects and hairpin defects are generated in the order of lightening defects and hairpin defects along the floating direction (that is, along the direction from the portion near the alignment film surface of the liquid crystal molecules to the portion where the liquid crystal molecules float from the alignment film surface due to pretilt). A state in which another orientation state surrounded by defects occurs, or another orientation state surrounded by hairpin defects and lightening defects by applying a strain to a foreign substance or a cell such as a spacer in a cell, and the rubbing direction is caused. Other orientation states surrounded by these defects occur in the order of lightning defects, hairpin defects State or, smectic A (Sm
It can be said that there is a state in which there is no orientation change accompanying the occurrence of lightening defects and / or hairpin defects in the process of lowering the temperature from high temperature such as A) to chiral smectic C (Sm ^* C).

The difference between the splay state and the uniform state in the C1 orientation of the present invention is a difference in contrast in addition to the difference in apparent tilt angle described above. As described above, in the splay orientation, a complete extinction position cannot be obtained under crossed nicols even in a dark state, and it becomes darker when the polarizing plate is arranged at a position twisted several degrees from the crossed nicols. On the other hand, the uniform orientation shows a high contrast ratio because there is almost perfect extinction position under crossed Nicols. This difference becomes even more pronounced when the following measurements are taken.

First, the absorption axis of one of the polarizing plates is aligned with the position where the contrast between the two states of up and down disappears under crossed Nicols, that is, the direction in which the angle between the optical axes of the two states is bisected (the smectic layer direction). To the absorption axis of the other polarizing plate. When only the analyzer (observer-side polarizing plate) is rotated clockwise at an appropriate angle of 3 ° to 30 ° from this position, a difference occurs in the transmitted light state between the up and down two states, and contrast is obtained. In many cases, the up state looks dark, and the down state becomes pale. Conversely, when the analyzer is rotated counterclockwise by the same angle, the reverse coloring is observed. That is, the up state becomes lighter and the down state becomes darker.

Therefore, focusing on the state of coloring with respect to the rotation of the analyzer, if the cell has a gap of 1.0 μm to 2.0 μm, (1) the up / down state of the splay alignment, and The color is brown or magenta, while the color of the down when rotated in a counterclockwise direction is blue or indigo, and the two colors are different. On the other hand, in the (2) uniform up-down 2 state, the above two colors are either brown or magenta, which are the same. This difference can be considered to be based on whether or not the director is twisted between the upper and lower substrates, as described later. In any case, the spray orientation and the uniform orientation can be qualitatively distinguished from this measurement.

In the present invention, the four states of the C1 orientation transition with each other when an electric field is applied. When a weak positive / negative pulse electric field is applied, a transition between the spray 2 states occurs, and when a strong positive / negative pulse electric field is applied, a transition between the uniform 2 states occurs. When the uniform 2 state is used, a brighter and higher-contrast display element can be realized.

By the way, there is a difference in the easiness of the uniform state depending on how the liquid crystal is selected. Table 3 shows the results obtained by examining the presence or absence of a uniform state in some liquid crystals using the alignment film C shown in Table 1. It can be seen that the liquid crystal having a small tilt angle easily takes a uniform state. Although the cause is not always clear, the following is presumed.

In the uniform state, it is considered from the optical properties that the director is not twisted between the upper and lower substrates. FIG. 7A is a schematic diagram showing the arrangement of directors at each position between substrates in each state of C1 orientation. In the figure 51
Reference numerals 54 show projections of the director on the bottom surface of the cone in each state, as viewed from the bottom surface direction. Reference numerals 51 and 52 denote splay states, and reference numerals 53 and 54 denote director arrangements considered to be in a uniform state. As can be seen from the figure, in the two states 53 and 54 of the uniform, the position of the liquid crystal molecule at the upper or lower substrate interface is replaced with the position in the spray state. FIG. 7 (B) shows the C2 orientation, in which there is no switching at the interface and there are two states by internal switching. FIG. 8 shows a director near the boundary between two regions having different interface molecular positions. Since the position of the interface molecule is considered to move from one side to the other through the vertex 60 of the cone as shown in the figure, the smaller the tilt angle is, the easier it is to move. For this reason, a uniform state is realized with a liquid crystal having a small tilt angle.

The direction of the torque that the molecules at the interface undergo when moving from one position to the other by an electric field depends on where the molecules are on the cone. That is, if the pretilt is higher than the cone ends 61 and 62 in FIG. 8, torque is applied in the direction passing through the vertex 60 of the cone, and if the pretilt is lower than the cone ends 61 and 62, the molecules are transferred to the substrate. Receives torque in the direction in which it is pressed. Therefore, switching is more likely to occur in the former position. The condition for the pretilt to be higher than the cone ends 61 and 62 is sinα> sinδcosθ (5) based on simple geometrical considerations. When the pretilt angle α, the layer inclination angle δ, and the tilt angle Θ are small, The condition is approximately α> δ (6). Since the layer inclination angle δ has a value close to the tilt angle θ, it can be interpreted that the experimental results shown in Table 3 were obtained.

Therefore, in order to more stably form the uniform state in the C1 orientation, it is effective to further satisfy the relationship of δ> α.

Further, in order to stably form a uniform state, cross rubbing in which the rubbing directions of the upper and lower substrates are shifted within a range of 0 to 20 ° is also possible.

As described above, when the uniform 2 state in the C1 orientation is used, a brighter and higher-contrast display element can be realized.

And, the present invention, as a method of suitably driving the liquid crystal element showing a uniform state in the C1 orientation, forming a scanning signal applied to the scanning electrode from two phases of an erasing phase and a writing phase having different polarities, A means for applying a scanning signal in which the absolute value of the voltage value in the pixel in the erase phase is larger than the absolute value of the voltage value in the pixel in the write phase is applied.

Thereby, for example, a liquid crystal element capable of displaying a better image in which the problem relating to the drive margin is improved by several steps as compared with the case where the multiplex driving shown in FIG. 2 is applied to the element in which the above-described uniform orientation is realized is obtained. It becomes possible.

Hereinafter, a specific example of the scanning signal applying unit of the present invention will be described.

FIG. 1A shows an example of a driving waveform in the present invention, and FIG. 1B is a timing chart when the pixel pattern shown in FIG. 9 is displayed using the driving waveform.

In FIG. 1A, S _S is a scanning selection signal waveform, S _NS
The scan non-selection signal waveform, I _W is white write signal waveform, I _a represents the black write signal waveform.

In this example, V ₁ : V ₂ : V ₃ = 3: 2: 1 t ₁ : t ₂ = 2: 1. Here, assuming that V ₁ : V ₂ : V ₃ = 3: 3: 1, this matches the conventional example of FIG.

According to experiments of the present inventors, the cause no drive margin in the driving waveform of the conventional example during half-selected (I _B -S _S), erase inhibited by half-select pulse after the erase pulse, as a result the cross It has been investigated that a talk is occurring. Therefore, in the uniform orientation, it becomes clear that a stronger erasing process is required for writing, and as described above, the absolute value of the voltage value of the erasing phase is larger than the absolute value of the voltage value of the writing phase. That's how it works.

Moreover, if simply performed strongly erasing process, to equal the voltage value and the write phase, but it is also possible by lengthening the pulse width t ₁ of the erase phase to the pulse width t ₂ of the write phase, lengthening the t ₁ is longer one line selection time, undesirable practical results in deteriorating the frame frequency.

Incidentally, the tilt angle Θ in the above experiments, the inclination angle of the layer [delta], the pretilt angle alpha, the tilt angle theta _a apparent was measured as follows.

Measurement of tilt angle し な が ら While applying DC of 10 V to 30 V between the upper and lower substrates of the FLC element, rotate the FLC element disposed between them under the crossed Nicols horizontally with the polarizing plate and rotate the first extinction position (transmittance) Is lowest), and then the second extinction position is searched for while applying DC of the opposite polarity to that described above. Then, 1/2 of the angle from the first extinction position to the second extinction position was defined as Θ.

After the application of the tilt angle θ measurement threshold single pulse of the liquid crystal of _a apparent, under no electric field, the FLC elements arranged in orthogonal crossed Nicols under therebetween looking for first extinction position by rotating horizontally and a polarizing plate, Next, after applying a pulse having a polarity opposite to that of the above-mentioned single pulse, a second extinction position is searched for under no electric field. Then, from the first extinction position, the second
1/2 of the angle of up to extinction position was θ _a.

Measurement of Tilt Angle δ of Layer δ was measured by an X-ray analysis method using an X-ray analyzer RAD-IIB (45 kV, 30 mA).

Measurement of pretilt angle α Jpn.J.Appl.Phys.vol.19 (1980) No.10 Short Notes
Determined according to the method described in 2013 (crystal rotation method).

That is, a substrate having a cell thickness of 20 μm was prepared by bonding substrates rubbed in parallel and in opposite directions, and a liquid crystal (A) having an SmA phase was sealed in a temperature range of 0 ° C. to 60 ° C. for measurement.

While rotating the liquid crystal cell in a plane perpendicular to the upper and lower substrates and including the alignment axis, a helium-neon laser beam having a polarization plane that forms an angle of 45 ° with the rotation axis is irradiated from the direction perpendicular to the rotation axis. The transmitted light intensity was measured by a photodiode through a polarizing plate having a transmission axis parallel to the incident polarization plane. Then, the angle between the line that is the center of the group of hyperbolas of the transmitted light intensity generated by the interference and the line that is perpendicular to the liquid crystal cell is φ
to determine the pre-tilt angle α ₀ is substituted into the following equation as _x.

[Example] Hereinafter, an example of the present invention will be described.

Example 1 A thin film of tantalum oxide on a glass substrate provided with a transparent electrode was formed by a sputtering method, and a 1% NMP solution of a polyamic acid LQ1802 manufactured by Hitachi Chemical Co., Ltd. was applied on the thin film by a spinner, and then 270.
Calcination was carried out at ℃ for 1 hour. Next, this substrate was rubbed, and a bonded cell was prepared while maintaining a 1.5 μm gap so that the rubbing direction was parallel and the same direction as another substrate subjected to the same treatment. The pretilt angle of the cell is 14 ° by the crystal rotation method. A ferroelectric liquid crystal having a tilt angle of 12 ° at room temperature and a layer tilt angle of 10 ° at room temperature was injected into the cell with a mixed liquid crystal containing phenylpyrimidine as a main component. The phase transition temperatures were as follows.

The display area of the panel in this cell is 114 × 2
28 mm.

The results of evaluating the display characteristics in the uniform state are shown below.

After sandwiching the above-mentioned liquid crystal cell between a pair of 90 ° crossed Nicol polarizers, and then applying a 30 V pulse of 50 μsec,
The 90 ° crossed Nicols is set to the extinction position (darkest state), the transmittance at this time is measured by a photomultiplier, and a −30 V pulse of 50 μsec is applied, and the transmittance (bright state) at this time is measured. When measured in the same manner, the transmittance in the dark state was 0.5% and the transmittance in the bright state was 10%, and thus the contrast ratio was 50: 1. The device has good contrast.

Next, the multiplexing drive was performed by applying the drive waveform voltage shown in FIG. 1 to the above ferroelectric liquid crystal cell under the following conditions.

V ₁ : V ₂ : V ₃ = 3: 2: 1 t ₁ : t ₂ = 2: 1 V _OP = | V ₁ + V ₃ | = 25 V At that time, when the pulse width t ₂ is in the range of 80 to 180 μsec at room temperature. A good image could be displayed.

That, t the range of the image can be displayed pulse width from t _{a b} (t _b
> As t _a) Is the drive margin, the drive margin M at this time was 0.38.

This makes it possible to obtain a stable and normal display over the entire display screen as compared with the case where an image is formed by setting V ₁ : V ₂ : V ₃ = 3: 3: 1.

Example 2 FIG. 10B using the driving waveform shown in FIG.
When the image was formed in the same manner as in Example 1 except that the driving was performed according to the timing shown in FIG. 4 and t ₁ : t ₂ = 3: 2, good display was obtained and M = 0.33. . Further, with this driving waveform, flicker of an image was significantly reduced as compared with the first embodiment.

Example 3 Example 2 was repeated except that the driving waveform shown in FIG. 11 was used.
When an image was formed in exactly the same manner as in Example 1, good display was obtained, and M = 0.30. In this drive waveform,
The frame frequency increased about 1.7 times as compared with the second embodiment.

[Effect of the Invention] As described above, according to the present invention, the liquid crystal element is controlled so as to be uniformly in the C1 alignment state throughout the liquid crystal element, and the scanning signals applied to the scanning electrodes are erased with different polarities. It is formed from two phases, a phase and a writing phase, and the absolute value of the voltage value of the erasing phase is set to be larger than the absolute value of the voltage value of the writing phase. Therefore, the driving margin becomes sufficiently large, and the contrast is high. An image with high transmittance can be displayed.

[Brief description of the drawings]

FIGS. 1 (a) and 1 (b) show a multi-unit which can be used in the present invention.
FIG. 2 is a driving waveform diagram of a conventional example, FIG. 3 (a) to (e) are explanatory diagrams showing a cooling process of a ferroelectric liquid crystal, and FIG. 4 is a C1 orientation. FIG. 5 is a schematic view showing an example of a ferroelectric liquid crystal cell of the present invention. FIGS. 6 (a) and (b) are smectic C phases near a substrate interface. FIG. 7 (A) is a schematic diagram showing the arrangement of directors at each position between substrates in each state of C1 orientation, and FIG. 7 (B) is a schematic diagram showing the arrangement of directors in C2 orientation. FIG. 8 is a schematic diagram showing the arrangement of directors at each position between substrates in a state, FIG. 8 is a schematic diagram showing a director near a boundary between two regions having different interfacial molecular positions, and FIG. FIGS. 10 (a) and (b) and FIG. 11 are plan views showing display examples according to the embodiment. FIG. 12 is a structural diagram of a polyamic acid used for an alignment film. S _S : Scan selection signal waveform, S _NS : Scan non-selection signal waveform,
I _W: white write signal waveform, I _B: black write signal waveforms, t _1: the pulse width of the erasing phase, t _2: writing phase of the pulse width, 21, 22: C1
Orientation state, 24, 25: C2 orientation state, 31: smectic layer, 32:
C1 oriented area, 33: C2 oriented area, Δ: cone angle, α:
Pretilt angle, δ: layer inclination angle.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masanobu Asaoka 3- 30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Shunji 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (56) References JP-A-3-243920 (JP, A) JP-A-61-267739 (JP, A) JP-A-2-273724 (JP, A)

Claims (31)

(57) [Claims] 1. A pretilt of a ferroelectric liquid crystal, comprising a pair of substrates having a scanning electrode group and an information electrode group, each of which has been subjected to a uniaxial alignment treatment, and a ferroelectric liquid crystal disposed between the substrates. If the angle is α, the tilt angle is Θ, and the tilt angle of the chiral smectic layer of the ferroelectric liquid crystal with respect to the substrate normal is δ,
The ferroelectric liquid crystal has an alignment state represented by Θ <α + δ, and the ferroelectric liquid crystal in the alignment state shows at least two stable states, and is θ which is 1/2 of the angle formed by their optical axes. _a and a tilt angle の of the ferroelectric liquid crystal are formed from a liquid crystal element having an alignment state represented by Θ> θ _a > Θ / 2, and two phases having an erasing phase and a writing phase having mutually different polarities, A liquid crystal comprising: means for applying a scanning signal to the scanning electrode group, the scanning signal having an absolute value of a voltage value applied to the pixel in the erasing phase greater than an absolute value of the voltage value applied to the pixel in the writing phase. apparatus. 2. A pretilt of a ferroelectric liquid crystal, comprising a pair of substrates provided with a scanning electrode group and an information electrode group, each of which has been subjected to a uniaxial alignment treatment, and a ferroelectric liquid crystal disposed between the substrates. If the angle is α, the tilt angle is Θ, and the tilt angle of the chiral smectic layer of the ferroelectric liquid crystal with respect to the substrate normal is δ,
The ferroelectric liquid crystal has an alignment state represented by Θ <α + δ, and the ferroelectric liquid crystal in the alignment state shows at least two stable states, and is located at a position where the angle between the optical axes is bisected. From the arrangement where the absorption axis of one polarizing plate is aligned and the absorption axis of the other polarizing plate is aligned perpendicular to it, only one polarizing plate is turned clockwise by 3 ° or more.
A liquid crystal element having the same color in the first stable state when rotated by 30 ° and the same color in the second stable state when rotated counterclockwise by the same angle; and erasures having different polarities from each other A scan signal formed from two phases, a write phase and a write phase, in which the absolute value of the voltage value applied to the pixel in the erase phase is larger than the absolute value of the voltage value applied to the pixel in the write phase A liquid crystal device comprising: means for applying a voltage to a liquid crystal device. 3. A pretilt of a ferroelectric liquid crystal, comprising a pair of substrates provided with a scanning electrode group and an information electrode group, each of which is subjected to a uniaxial alignment treatment, and a ferroelectric liquid crystal disposed between the substrates. If the angle is α, the tilt angle is Θ, and the tilt angle of the chiral smectic layer of the ferroelectric liquid crystal with respect to the substrate normal is δ,
The ferroelectric liquid crystal has an alignment state represented by Θ <α + δ, and the ferroelectric liquid crystal in the alignment state has two stable states under crossed Nicols and low transmittance in an extinction position, and under crossed Nicols and quenched. Liquid crystal element having a total of three or four stable states of one or two stable states having high transmissivity, and two phases of an erasing phase and a writing phase having different polarities from each other, and applied to a pixel having the erasing phase. A liquid crystal device comprising: means for applying a scanning signal to the scanning electrode group in which the absolute value of the applied voltage value is larger than the absolute value of the voltage value applied to the pixel of the writing phase. 4. The first and second stable states in which the ferroelectric liquid crystal has low transmittance at the extinction position under crossed Nicols, and the third and fourth stable states have high transmittance at the extinction position under crossed Nicols. The four stable states of the above two are shown, and the absorption axis of one polarizing plate is aligned with the position where the angle between the optical axes is divided into two equal parts, and the absorption axis of the other polarizing plate is aligned perpendicularly thereto. The color in the first stable state when only one of the polarizers is rotated clockwise by 3 ° to 30 ° from the arrangement, and the color in the second stable state when rotated by the same angle in the counterclockwise direction Are the same, and the color of the third stable state when only one of the polarizing plates is rotated clockwise by 3 ° to 30 °, and the fourth stable state when rotated by the same angle in the counterclockwise direction 4. The liquid crystal device according to claim 3, wherein the color of the liquid crystal is different. 5. A pair of substrates provided with a scanning electrode group and an information electrode group, each of which has been subjected to a uniaxial alignment process, wherein the pair of substrates have the uniaxial alignment process in the same direction, and are disposed between the substrates. Having a ferroelectric liquid crystal, the main alignment state of the ferroelectric liquid crystal is caused by foreign substances between the substrates or by applying a strain to the substrate, causing other alignment states surrounded by hairpin defects and lightning defects, In the other alignment state, the liquid crystal molecules are surrounded by these defects generated in the order of the lightning defect and the hairpin defect along the direction in which the liquid crystal molecules float from the alignment film surface due to the pretilt. ferroelectric liquid crystal exhibits at least two stable states, the table in their one-half of the angle between the optical axis theta _a and ferroelectric liquid crystal tilt angle theta and the Θ> θ _a> Θ / 2 A liquid crystal element, and an absolute value of a voltage value applied to a pixel having the erase phase and a voltage value applied to the pixel having the write phase, which is formed from two phases of an erase phase and a write phase having different polarities from each other. A liquid crystal device comprising: means for applying a scanning signal larger than the absolute value of the scanning electrode group to the scanning electrode group. 6. A pair of substrates provided with a scanning electrode group and an information electrode group, each of which has been subjected to a uniaxial alignment process, wherein the pair of substrates have the uniaxial alignment process in the same direction, and are disposed between the substrates. Having a ferroelectric liquid crystal, the main alignment state of the ferroelectric liquid crystal is caused by foreign substances between the substrates or by applying a strain to the substrate, causing other alignment states surrounded by hairpin defects and lightning defects, In the other alignment state, the liquid crystal molecules are surrounded by these defects generated in the order of the lightning defect and the hairpin defect along the direction in which the liquid crystal molecules float from the alignment film surface due to the pretilt. The dielectric liquid crystal shows at least two stable states, and aligns the absorption axis of one of the polarizers at a position that bisects the angle between their optical axes;
The same angle in the counterclockwise direction as the color in the first stable state when only one of the polarizing plates is rotated clockwise by 3 ° to 30 ° from the arrangement in which the absorption axis of the other polarizing plate is aligned perpendicularly thereto. A liquid crystal element having the same color in the second stable state when rotated, and a voltage value formed from two phases of an erasing phase and a writing phase having mutually different polarities and applied to a pixel having the erasing phase A means for applying a scanning signal whose absolute value is larger than the absolute value of the voltage value applied to the pixel in the writing phase to the scanning electrode group. 7. A pair of substrates provided with a scanning electrode group and an information electrode group, each of which has been subjected to a uniaxial alignment process, wherein the pair of substrates have the uniaxial alignment process in the same direction, and are disposed between the substrates. Having a ferroelectric liquid crystal, the main alignment state of the ferroelectric liquid crystal is caused by foreign substances between the substrates or by applying a strain to the substrate, causing other alignment states surrounded by hairpin defects and lightning defects, The other alignment state is surrounded by these defects that occur in the order of lightning defects and hairpin defects along the direction in which the liquid crystal molecules float from the alignment film surface due to pretilt. Liquid crystal has two stable states under crossed Nicols with low extinction transmittance,
A liquid crystal element having a total of 3 or 4 states of one or two stable states with high transmittance in the extinction position under crossed Nicols, and two phases of an erasing phase and a writing phase having polarities different from each other. A liquid crystal device comprising: means for applying a scan signal to a scan electrode group, the scan signal having an absolute value of a voltage value applied to a pixel of a phase greater than an absolute value of a voltage value applied to a pixel of the write phase. 8. The first and second stable states in which the ferroelectric liquid crystal has a low transmittance at an extinction position under crossed Nicols, and the third and fourth stable states have a high transmittance at an extinction position under crossed Nicols. The four stable states of the above two are shown, and the absorption axis of one polarizing plate is aligned with the position where the angle between the optical axes is divided into two equal parts, and the absorption axis of the other polarizing plate is aligned perpendicularly thereto. The color in the first stable state when only one polarizer is rotated clockwise by 3 ° to 30 °, and the color in the second stable state when rotated counterclockwise by the same angle. Are the same, the color of the third stable state when only one of the polarizing plates is rotated clockwise by 3 ° to 30 °, and the fourth stable state when the same polarizer is rotated counterclockwise by the same angle 8. The liquid crystal device according to claim 7, wherein the colors of the liquid crystal display are different. 9. A pair of substrates provided with a scanning electrode group and an information electrode group, each of which has been subjected to a uniaxial alignment process, wherein the pair of substrates have the uniaxial alignment process in the same direction, and are disposed between the substrates. Having a ferroelectric liquid crystal, the main alignment state of the ferroelectric liquid crystal is caused by foreign substances between the substrates or by applying a strain to the substrate, causing other alignment states surrounded by hairpin defects and lightning defects, This other alignment state is surrounded by these defects that occur in the order of lightening defects and hairpin defects along the uniaxial alignment processing direction, and the ferroelectric liquid crystal in the main alignment state has at least two stable states. shows, the liquid crystal element and their is a half of the angle between the optical axis theta _a and ferroelectric liquid crystal tilt angle theta is represented by _{Θ> θ a> Θ / 2} , and, different polarities A scan signal formed from two phases, a left phase and a write phase, in which the absolute value of the voltage value applied to the pixel in the erase phase is larger than the absolute value of the voltage value applied to the pixel in the write phase A liquid crystal device comprising: means for applying a voltage to a group. 10. A pair of substrates provided with a scanning electrode group and an information electrode group, each of which has been subjected to a uniaxial alignment process, wherein the pair of substrates have the uniaxial alignment process in the same direction, and are disposed between the substrates. Having a ferroelectric liquid crystal, the main alignment state of the ferroelectric liquid crystal is caused by foreign substances between the substrates or by applying a strain to the substrate, causing other alignment states surrounded by hairpin defects and lightning defects, The other alignment state is surrounded by these defects that occur in the order of lightening defects and hairpin defects along the uniaxial alignment processing direction, and the ferroelectric liquid crystal in the main alignment state has at least two stable states. Shown, the absorption axis of one of the polarizing plates is aligned with the position at which the angle between the optical axes is divided into two equal parts, and the absorption axis of the other polarizing plate is aligned vertically with the absorption axis of the other polarizing plate. A liquid crystal in which the color in the first stable state when only the light plate is rotated clockwise by 3 ° to 30 ° is the same as the color in the second stable state when rotated by the same angle in the counterclockwise direction. An element, and an absolute value of a voltage value applied to the pixel of the writing phase formed from two phases of an erasing phase and a writing phase having different polarities, and the absolute value of the voltage value applied to the pixel of the erasing phase is determined. A liquid crystal device, comprising: means for applying a larger scanning signal to a scanning electrode group. 11. A pair of substrates provided with a scanning electrode group and an information electrode group, each of which has been subjected to a uniaxial alignment process, wherein the pair of substrates have the uniaxial alignment process in the same direction, and are disposed between the substrates. Having a ferroelectric liquid crystal, the main alignment state of the ferroelectric liquid crystal is caused by foreign substances between the substrates or by applying a strain to the substrate, causing other alignment states surrounded by hairpin defects and lightning defects, The other alignment state is surrounded by these defects that occur in the order of lightening defects and hairpin defects along the uniaxial alignment processing direction, and the ferroelectric liquid crystal in the main alignment state is under crossed Nicols, and has an extinction position. Two stable states with low transmittance and one with high transmittance in the extinction position under crossed Nicols
A liquid crystal element having a total of three or four states in one or two stable states, and an absolute value of a voltage value formed of two phases of an erasing phase and a writing phase having polarities different from each other and applied to a pixel having the erasing phase A means for applying a scanning signal larger than the absolute value of the voltage value applied to the pixel of the writing phase to the scanning electrode group. 12. The first and second stable states in which the ferroelectric liquid crystal has a low transmittance at an extinction position under crossed Nicols, and the third and fourth stable states have a high transmittance at an extinction position under crossed Nicols. The four stable states of the above two are shown, and the absorption axis of one polarizing plate is aligned with the position where the angle between the optical axes is divided into two equal parts, and the absorption axis of the other polarizing plate is aligned perpendicularly thereto. The color in the first stable state when only one of the polarizers is rotated clockwise by 3 ° to 30 ° from the arrangement, and the color in the second stable state when rotated by the same angle in the counterclockwise direction Are the same, and the color of the third stable state when only one of the polarizing plates is rotated clockwise by 3 ° to 30 °, and the fourth stable state when rotated by the same angle in the counterclockwise direction 12. The liquid crystal device according to claim 11, wherein the liquid crystal device has different colors. 13. A ferroelectric liquid crystal comprising a pair of substrates having a scanning electrode group and an information electrode group, each of which has been subjected to a uniaxial alignment treatment, and a ferroelectric liquid crystal disposed between the substrates. In the process of lowering the temperature from a high temperature region showing the SmA phase to a temperature region showing the Sm ^* C phase, there is no alignment change accompanied by the occurrence of lightning defects and / or hairpin defects, and at least the ferroelectric liquid crystal in the alignment state shows two stable states, the liquid crystal device and theta _a and ferroelectric properties tilt angle of the liquid crystal theta is half the angle between the optical axes thereof are represented by _{Θ> θ a> Θ / 2} , and, A scan formed from two phases of an erasing phase and a writing phase having different polarities, wherein the absolute value of the voltage value applied to the pixel in the erasing phase is larger than the absolute value of the voltage value applied to the pixel in the writing phase Means for applying signals to the scanning electrode group A liquid crystal device characterized by. 14. A semiconductor device comprising: a pair of substrates provided with a scanning electrode group and an information electrode group, each of which is subjected to a uniaxial alignment treatment; and a ferroelectric liquid crystal disposed between the substrates. In the process of lowering the temperature from a high temperature region showing the SmA phase to a temperature region showing the Sm ^* C phase, there is no alignment change accompanied by the occurrence of lightning defects and / or hairpin defects, and at least the ferroelectric liquid crystal in the alignment state The two stable states are shown, and the absorption axis of one of the polarizing plates is aligned at a position bisecting the angle formed by the optical axes, and the absorption axis of the other polarizing plate is aligned perpendicularly to the one polarizing plate. A liquid crystal element having the same color as that of the first stable state when it is rotated clockwise by 3 ° to 30 °, and the same color that the second stable state when it is rotated counterclockwise by the same angle. , And erasure phases of different polarities A scan signal formed from the two phases of the write phase and a write signal in which the absolute value of the voltage value applied to the pixel in the erase phase is larger than the absolute value of the voltage value applied to the pixel in the write phase is applied to the scan electrode group. A liquid crystal device comprising: means for applying voltage. 15. A ferroelectric liquid crystal comprising: a pair of substrates each having a scanning electrode group and an information electrode group, each of which has been subjected to a uniaxial alignment treatment, and a ferroelectric liquid crystal disposed between the substrates. In the process of lowering the temperature from the high temperature region where the alignment state shows the SmA phase to the temperature region showing the Sm ^* C phase, there is no alignment change accompanied by the occurrence of lightning defects and / or hairpin defects, and the ferroelectric liquid crystal in the alignment state crosses. A liquid crystal element having a total of 3 or 4 states under Nicol and two stable states with low transmittance at the extinction position and one or two stable states under crossed Nicols with high transmittance at the extinction position; Scanning a scanning signal formed from two phases of different erasing phase and writing phase, wherein the absolute value of the voltage value applied to the pixel of the erasing phase is larger than the absolute value of the voltage value applied to the pixel of the writing phase For electrode group A liquid crystal device comprising: means for applying voltage. 16. The ferroelectric liquid crystal has first and second stable states having low transmittance at an extinction position under crossed Nicols, and third and fourth stable states having high transmittance at an extinction position under crossed Nicols. The four stable states of the above two are shown, and the absorption axis of one polarizing plate is aligned with the position where the angle between the optical axes is divided into two equal parts, and the absorption axis of the other polarizing plate is aligned perpendicularly thereto. The color in the first stable state when only one of the polarizers is rotated clockwise by 3 ° to 30 ° from the arrangement, and the color in the second stable state when rotated by the same angle in the counterclockwise direction Are the same, and the color of the third stable state when only one of the polarizing plates is rotated clockwise by 3 ° to 30 °, and the fourth stable state when rotated by the same angle in the counterclockwise direction 16. The liquid crystal device according to claim 15, wherein the color of the liquid crystal is different. 17. The liquid crystal device according to claim 1, wherein the alignment state has three or four different stable states that do not involve a lightning defect and a hairpin defect. 18. A pre-tilt angle α of the liquid crystal is 6 ° <α <
The liquid crystal device according to claim 1, wherein the angle is 30 °. 19. A pretilt angle α of the liquid crystal is 8 ° <α <
The liquid crystal device according to claim 1, wherein the angle is 30 °. 20. A pretilt angle α of the liquid crystal is 10 ° <α <
The liquid crystal device according to claim 1, wherein the angle is 30 °. 21. When the pretilt angle of the liquid crystal is α,
The liquid crystal device according to claim 5, wherein 6 ° <α <30 °. 22. When the pretilt angle of the liquid crystal is α,
The liquid crystal device according to claim 5, wherein 8 ° <α <30 °. 23. When the pretilt angle of the liquid crystal is α,
The liquid crystal device according to claim 5, wherein 10 ° <α <30 °. 24. The tilt angle Θ of the liquid crystal is 7 ° <Θ <27.
The liquid crystal device according to claim 1, wherein the angle is °. 25. When the tilt angle of the liquid crystal is Θ, 7 ° <Θ.
The liquid crystal device according to claim 5, wherein the angle is <27 °. 26. A pretilt of the chiral smectic liquid crystal, comprising: a pair of substrates provided with a scanning electrode group and an information electrode group, each of which has been subjected to a uniaxial alignment treatment; and a chiral smectic liquid crystal disposed between the substrates. When the angle is α, the tilt angle is Θ, and the tilt angle of the chiral smectic layer with respect to the substrate normal is δ, the chiral smectic liquid crystal has an alignment state represented by Θ <α + δ, and the chiral smectic liquid crystal in the alignment state There exhibits at least two stable states, a liquid crystal element having those is 1/2 of the angle of the optical axis theta _a and the liquid crystal and the tilt angle theta is Θ> θ _a> Θ / 2 in relation to each other It is formed from two phases of erase phase and write phase having different polarities, and the absolute value of the voltage value applied to the pixel at the erase phase is larger than the voltage value applied to the pixel at the write phase. A liquid crystal device characterized in that it comprises a means for applying a listening scan signal to the scan electrode group. 27. The liquid crystal device according to claim 26, wherein a pretilt angle α of the chiral smectic liquid crystal satisfies 6 ° <α <30 °. 28. The liquid crystal device according to claim 26, wherein the tilt angle の of the chiral smectic liquid crystal is 7 ° <Θ <27 °. 29. The liquid crystal device according to claim 26, wherein the relationship between the pretilt angle α and the tilt angle δ of the chiral smectic liquid crystal has an alignment state represented by δ <α. 30. The liquid crystal device according to claim 1, wherein the uniaxial alignment treatment performed on each of the pair of substrates is a rubbing treatment. 31. The liquid crystal device according to claim 30, wherein the rubbing directions applied to each of the pair of substrates cross each other so as to form an angle of 20 ° or less.