JP3083016B2 - Liquid crystal alignment treatment method and liquid crystal element manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a chiral smectic.
Cell structure suitable for liquid crystals exhibiting phases, especially ferroelectric liquid crystals, and
And alignment treatment method suitable for the liquid crystal, and liquid crystal element containing the same
A method for manufacturing a child.

[0002]

2. Description of the Related Art Clark and Lagerwall have proposed a display device of a type that controls transmitted light in combination with a polarizing plate using the refractive index anisotropy of ferroelectric liquid crystal molecules. (JP-A-56-107216, U.S. Pat.
Issue specification). This ferroelectric liquid crystal generally has a chiral smectic phase in a specific temperature range, and in this state, in response to an applied electric field, one of the first optical stable state and the second optical 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, and is expected to be widely used as a high-speed and storage-type display element. ing.

[0003]

However, if the cell using the liquid crystal exhibiting the chiral smectic phase is driven for a long time , the movement of the liquid crystal molecules in the cell occurs.
Flip, the cell thickness of the cell end will gradually increase, was recognized is a problem that appears tinted yellow. Accordingly, an object of the present invention is to reduce an increase in cell thickness at the end of a liquid crystal cell using a liquid crystal exhibiting a chiral smectic phase.

[0004]

In order to solve the above problems, the present invention provides a liquid crystal exhibiting a chiral smectic phase.
While holding the
An electrode for applying a voltage to the liquid crystal is formed, and
A pair of substrates processed to orient the liquid crystal.
In the obtained liquid crystal element, an alternating current is applied to the liquid crystal, and the alternating current is applied.
During the period of application, a liquid crystal alignment process for raising and lowering the temperature of the device.
Of liquid crystal device having process of alignment process
Provide a way. In addition, in the above-mentioned alignment treatment,
Temperature rise and fall within the temperature range of the smectic phase
And more preferably the temperature of the above element
In the step of elevating and lowering, the smectic A phase,
Raise and lower the temperature between the lusmectic phases.

(Detailed Description of Embodiments of the Invention) According to the study of the present inventors, the increase in the cell thickness at the cell edge described above causes the liquid crystal itself to move in a specific direction between the liquid crystal cells by driving. As a result, it was recognized that the pressure at the cell edge increased, and as a result, the cell thickness increased. The cause of the force that causes the liquid crystal molecules to move in the liquid crystal cell is unknown, but it is presumed that the dipole moment of the liquid crystal molecules fluctuates due to an alternating electric field caused by a driving pulse, and this is probably an electrodynamic effect. According to the experiments performed by the present inventors, the moving direction 22 is the rubbing direction 20 as shown in FIG.
And the average molecular axis directions 21 and 21 'of the liquid crystal molecules. Since the moving direction of the liquid crystal molecules depends on the rubbing direction in this way, it is presumed that the phenomenon depends on the state of pretilt at the substrate interface. The average molecular axis directions 21 and 21 'indicate the average molecular positions in the bistable state of the ferroelectric liquid crystal molecules. Here, for example, when an appropriate alternating current is applied such that the liquid crystal does not switch in the state where the average molecular axis direction is indicated by 21, the arrow 22
The liquid crystal molecules move in the direction. However, here, the case where a liquid crystal material having a negative spontaneous polarization direction is used is described. Further, this liquid crystal movement phenomenon depends on the alignment state of the cell. The orientation including the chevron structure of the smectic layer as shown in FIG. 3 can be explained by two types of orientation models C1 and C2. In FIG. 3, 31 is a smectic layer, 32
Represents a C1-oriented region, and 33 represents a C2-oriented region. Smectic liquid crystals generally have a layered structure,
Fig. 3 shows that the transition to the C or SC ^* phase shortens the phase interval.
The layer has a structure (chevron structure) bent at the center of the upper and lower substrates 11a and 11b as shown in FIG. As shown in the figure, there are two bending directions, C1 and C2. 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 tilted toward A (the tip is floating). Due to 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. When the layer structure of FIG. 3 is viewed in plan, a boundary 34 at the time of shifting from the C1 orientation to the C2 orientation in the rubbing direction A is called a lightning defect in a zigzag lightning shape, and a boundary 35 at the time of shifting from C2 to C1. Are wide, gently curved and are called hairpin defects.
A pair of substrates that have been subjected to uniaxial orientation processing in substantially the same direction for aligning the ferroelectric liquid crystal are provided. , The inclination angle of the SmC ^* layer is δ, and the ferroelectric liquid crystal is 1
There are four states having the orientation states represented by the equations.

Θ <α + δ ... 1 equation

[0007] The four C1 orientation states are different from the conventional C1 orientation state, and two of the four C1 orientation states form a bistable state (uniform state). Here, assuming that the apparent tilt angle in the absence of an electric field is θa, the state showing the relationship of the two equations among the four states in the C1 alignment state is called a uniform state.

Θ> θa> Θ / 2 ... 2

In the uniform state, it is considered from the optical properties that the director is not twisted between the upper and lower substrates. FIG. 4A is a schematic diagram showing the arrangement of directors at each position between substrates in each state of C1 orientation. In the figures, reference numerals 51 to 54 denote projections of the director on the bottom surface of the cone in each state, as viewed from the bottom surface. Reference numerals 51 and 52 denote spraying states, and 53 and 54 denote director arrangements considered to be in a uniform state. is there. As can be seen from FIG.
In 54 and 54, the position of the liquid crystal molecule at the upper or lower substrate interface is replaced with the position in the splay state. FIG.
(B) shows the C2 orientation, and there are two states 55 and 56 by internal switching without interface switching. The uniform state of the C1 orientation corresponds to the C2 orientation conventionally used.
A larger tilt angle θa is generated than in the bistable state in the orientation, and the brightness is large and the contrast is high.

In the actual liquid crystal cell, for example, as shown in FIG. 2, if the position of the liquid crystal molecules is in the state indicated by the arrow 21 in the entire cell, the movement of the liquid crystal molecules described above is caused by the inside of the cell. The liquid crystal moves from right to left. As a result, as shown in FIG. 2B, the cell thickness in the region 23 increases with time, and coloring occurs. When the liquid crystal molecules are in the state shown by the arrow 21 ', the movement under the AC electric field is reversed, but in any case, the rubbing direction 2
The liquid crystal moves in a direction perpendicular to 0, that is, in the smectic layer. Obviously, the movement of the liquid crystal as described above has an adverse effect on the durability of the liquid crystal element in continuous driving for a long time.

Therefore, the present invention provides a liquid crystal device having a chiral smectic phase, which is opposed to a liquid crystal having a chiral smectic phase therebetween, and an electrode for applying a voltage to the liquid crystal is formed on each of the opposing surfaces to align the liquid crystal. In a liquid crystal device comprising a pair of substrates that have been processed in the following manner, an alternating current is applied to the liquid crystal, and during the period of the alternating current, the temperature of the device is raised and lowered. a method of manufacturing a liquid crystal device using, preferably, lifting between the step of elevating the temperature of the element, decreasing the temperature in the smectic phase within, more preferably a smectic a phase, a chiral smectic phase By performing the heating, the above-described movement of the liquid crystal is reduced, and uniform alignment is realized. In particular, in the present invention, in the liquid crystal element, uniaxial alignment treatment is performed on the pair of substrates in substantially the same direction to align the liquid crystal, and more preferably, the angle (pretilt angle) formed between the interface between the pair of substrates and the liquid crystal molecules. In an element having α) of 10 ° or more, by applying an alternating current to the liquid crystal and raising or lowering the temperature of the element during the period of applying the alternating current, the movement of the liquid crystal is reduced optimally, and the uniform alignment Is remarkably realized.

FIG. 6 shows an example of an isotrope according to the present invention.
FIG. 7 shows the orientation after only slow cooling from the ic phase, and FIG. 7 shows the orientation after the treatment under the following conditions. It can be seen that the alignment defects on the wrinkles have been removed.

[0013]

[Outside 3]

FIG. 5A shows the measurement results before the processing, where θ ₁ = 78.95 ° (δ ₁ = 12.55 °) and θ ₂ = 10.
3.70 ° (δ ₂ = 12.2 °) FWHM ₁ = 2.25 ° and FWHM ₂ = 2.75 °. FIG. 5B shows the measurement results after the processing, where θ ₁ = 79.35 ° (δ ₁ = 12.15 °) and θ ₂ = 10.
2.55 ° (δ ₂ = 11.05 °) FWHM ₁ = 1.90 ° and FWHM ₂ = 1.85 °.

An increase in the integrated intensity of the diffraction peak indicates that the order of the layer structure is increased.
Also, the narrowing of the peak half width indicates that the layer structure has changed to a clear chevron structure.

As shown in FIG. 1, this liquid crystal cell comprises a pair of parallel upper and lower substrates 11a and 11b, and transparent electrodes 12a and 12b each having a thickness of about 400-3000.degree. I have. A ferroelectric liquid crystal 15 is arranged between the upper substrate 11a and the substrate 11b. On the transparent electrodes 12a and 12b, insulating films 13a and 13b having a thickness of, for example, 100 to 3000 ° are formed. The insulating film in the present invention may be a coating and firing type inorganic oxide, a sputtered film, or a multi-layered film having two or more layers. 14a and 14b are orientation control layers which are usually formed at 50-1000 °. Usually, a high-molecular polymer is used, but in the device of the present invention, an orientation control film that gives high pretilt, such as fluorine-containing polyimide, is preferable. Pretilt value is 10-30 °
Is preferred. As the alignment treatment method, a method of rubbing a polymer is usually used.

When rubbing the upper and lower substrates, the upper and lower rubbing directions can be crossed within a range of 0-20 °. Thereby, the above-mentioned uniform state 53 and 5
4 can be stabilized, and higher contrast can be obtained. In the present invention, a ferroelectric liquid crystal having a chiral smectic phase can be used. Specifically, a chiral smectic C phase (Sm ^* C),
H phase (Sm ^* H), I phase (Sm ^* I), K phase (Sm ^* K)
Alternatively, a liquid crystal of G phase (Sm ^* G) can be used.

As a particularly preferred liquid crystal, a liquid crystal exhibiting a cholesteric phase at a high temperature side can be used. For example, a pyrimidine-based mixed liquid crystal exhibiting the following phase transition temperatures and physical properties can be used.

[0019]

[Outside 4]

[0020] The above physical parameters (cone angle theta, the angle of inclination of the layers [delta], tilt angle theta _a and the pretilt angle of the apparent) were measured as described above. Measurement of cone angle し な が ら 10-30V DC is applied between the upper and lower substrates of the FLC element, and the FLC is placed under and between the crossed Nicols.
Rotate the element horizontally with the polarizing plate to find the first extinction position (the position where the transmittance becomes lowest),
While searching for the second extinction position. The first at this time
1/2 of the angle from the extinction position to the second extinction position was defined as the cone angle Θ.

[0021] (Measurement of tilt angle theta _a apparent) after applying a single pulse of the liquid crystal threshold, no electric field under and orthogonal crossed Nicol state, the FLC device which is located on the horizontally polarizing plate therebetween After rotating to find the first extinction position, and then applying a pulse having a polarity opposite to that of the above-mentioned single pulse, the second extinction position is found without an electric field. Half of angle from the first extinction position at this time to a second extinction position was theta _a.

(X-Ray Diffraction of Smectic Layer Structure) The smectic layer structure was analyzed using an X-ray diffraction method.

The measuring method is basically based on Clark and lag.
erwall published method (Japan D
display '86. Sep. 30-Oct.
2, 1986, pp 456-458) or the method of Ouchi et al. (JJAP, 27 (5) (1988) p.
p725-728). First, the layer spacing of the liquid crystal was determined by coating the liquid crystal on a sample glass, performing 2θ / θ scanning in the same manner as in ordinary powder X-ray diffraction, and using the Bragg equation. Then, the layer structure of the smectic liquid crystal formed in the cell was determined by the method described in the above literature by scanning the cell with an X-ray detector at a diffraction angle 2θ corresponding to the layer spacing determined earlier and scanning the cell with θ. .

The X-ray diffractometer used was a rotating anti-cathode type MXP-18 manufactured by MAC Science Co., Ltd., and the κα ray of copper was used as the analysis line.

The setting conditions of the X-ray diffraction apparatus are as follows: X-ray output 50 kV × 300 mA = 15 kW Divergence slit 0, 5 ° Scanning slit 0, 5 ° Light receiving slit 0, 15 mm Sampling angle 0, 05 ° Scanning speed 10 ° / min The irradiation area is determined by the cell jig and slit,
It is 8.0 × 1.8 mm ² and the cell thickness is 1.5 μm. The background was removed by the Sonneverd method.

(Measurement of Pretilt Angle α) Jpn. J. A
ppl. Phys. vol. 19 (1980) NO. 1
0, according to the method described in Short Notes 2013 (crystal rotation method). That is, a substrate having a cell thickness of 20 μm is formed by bonding substrates rubbed in parallel and opposite directions,
The liquid crystal (A) having the SmA phase was sealed in the range of and the measurement was performed. While rotating the liquid crystal cell in a plane perpendicular to the upper and lower substrates and including the alignment processing axis, the liquid crystal cell is irradiated with helium / neon laser light having a polarization plane that forms an angle of 45 ° with the rotation axis from a direction perpendicular to the rotation axis, and the opposite side. The transmitted light intensity was measured by a photodiode through a polarizing plate having a transmission axis parallel to the incident polarization plane. The angle between a line perpendicular to the center to become the corner and the liquid crystal cell of the hyperbola group of the transmitted light intensity can by interference and phi _x, was determined pre-tilt angle α0 is substituted into the following equation.

[0027]

[Outside 5]

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a liquid crystal device according to the present invention is manufactured will be described below.

Example 1 A thin film of tantalum oxide was formed on a glass substrate provided with a 7.5 cm × 7.5 cm transparent electrode by a sputtering method, and 1% of a fluorine-based polyimide was formed thereon.
The NMP solution was applied with a spinner and baked at 270 ° C. for 1 hour. Next, this substrate was rubbed, and the cell thickness of 1.5 μm was adjusted so that the rubbing direction was twisted clockwise by 10 ° when viewed from above the cell from the same direction and parallel with another substrate subjected to the same treatment. The cell was created by holding and bonding. The pretilt angle of the cell was measured to be 20 ° by the crystal rotation method. A ferroelectric liquid crystal having a cone angle of 14 ° at room temperature and a layer tilt angle of 12 ° at room temperature was injected into the cell as a mixed liquid crystal containing phenylpyrimidine as a main component.

The phase transition temperatures were as follows:

[0031]

[Outside 6]

FIG. 7 shows the temperature change of the cone angle of the liquid crystal.

After the cells into which the liquid crystal was injected were aged at 100 ° C. for 5 hours, the following treatment was performed.

[0034]

[Outside 7]

The C1 orientation of the Sm ^* C phase was maintained over the entire temperature range, and uniform state switching by an electric field was possible. The following experiments were performed at 30 ° C. At this time,
The apparent tilt angle θa was 11.5 °.

Next, the cell orientation is aligned with the average molecular axes 81 and 82 as shown in FIG. 8 and the waveform (Vop = 25) shown in FIG.
After applying V, Δt = 25 μs for about 7 hours, FIG.
When the cell thickness in the region of 86 was measured, the deviation from the initial cell thickness was as shown in Table 1.

[0037]

[Table 1]

When this cell was sandwiched between crossed Nicol polarizing plates and coloration was confirmed by silent observation, the region where the cell thickness was increased or decreased could not be recognized.

As a result of the X-ray analysis, Table 1 shows the layer tilt angle δ, the peak half width, and the layer structure diffraction peak area. This result was obtained by performing the same treatment as above on a glass substrate having a thickness of 80 μm and by the above-described method. The cell thickness of this sample is 1.5 μm
Met. The layer structure diffraction peak area and half width were 103% and 1.15 times that of Comparative Example 3, respectively.

Example 2 The following processing was performed on an FLC device manufactured in exactly the same manner as in Example 1.

[0041]

[Outside 8]

The C1 orientation of the Sm ^* C phase was maintained over the entire temperature range, and uniform state switching by an electric field was possible. At this time, the tilt angle θ _a of the apparent 11.
5 °.

Next, the cell orientation is aligned with the average molecular axes 81 and 82 as shown in FIG. 8 and the waveform (Vop = 25 V,
Δt = 25 μs) for about 7 hours, and then 83-8 in FIG.
When the cell thickness in the area of No. 6 was measured, the deviation from the initial cell thickness was as shown in Table 2. In FIG. 9,
S _N , S _{N + 1} , S _{N + 2} are scanning signals supplied to the N, N + 1, N + 2nd scanning lines, I is an information signal, and I−S
_N and I−S _{N + 1} are drive signals applied to pixels corresponding to N and N + 1 scanning lines, respectively.

[0044]

[Table 2]

The cell was sandwiched between crossed Nicol polarizing plates, and coloration was confirmed by silent observation. As a result, an area where the cell thickness was increased or decreased could not be recognized.

Example 3 The following processing was performed on an FLC device manufactured in exactly the same manner as in Example 1.

[0047]

[Outside 9] The C1 orientation of the Am ^* C phase was maintained over the entire temperature range, and uniform state switching by an electric field was possible.
At this time, the tilt angle theta _a apparent was 11.5 °.

Next, the cell orientation is adjusted to the average molecular axes 81 and 82 as shown in FIG. 8 and the waveform (Vop = 25 V,
After applying Δt = 25 μs for about 7 hours, 83-86 in FIG.
When the cell thickness in the region was measured, the deviation from the initial cell thickness was as shown in Table 3.

[0049]

[Table 3]

When the cell was sandwiched between crossed polarizers and coloration was confirmed by silent gaze, the region where the cell thickness was increased or decreased could not be recognized.

Example 4 The following processing was performed on an FLC device manufactured in exactly the same manner as in Example 1.

[0052]

[Outside 10] The C1 orientation of the Sm ^* C phase was maintained over the entire temperature range, and uniform state switching by an electric field was possible.
At this time, the tilt angle theta _a apparent was 11.5 °.

Next, the cell orientation was adjusted to the average molecular axes 81 and 82 as shown in FIG. 8 and the waveform (Vop = 25 V,
After applying Δt = 25 μs for about 7 hours, 83-86 in FIG.
When the cell thickness in the region was measured, the deviation from the initial cell thickness was as shown in Table 4.

[0054]

[Table 4]

When the cell was sandwiched between crossed Nicols polarizing plates and coloration was confirmed by silent observation, the region where the cell thickness increased or decreased could not be recognized.

As a result of the X-ray analysis, Table 1 shows the layer tilt angle δ, the peak half width, and the layer structure diffraction peak area. This result was obtained by performing the same treatment as above on a glass substrate having a thickness of 80 μm and by the above-described method. The cell thickness of this sample is 1.5 μm
Met. This layer structure diffraction peak area and half width were 83% and 1.18 times of Comparative Example 3, respectively, and were Comparative Example 3.

Example 5 The following processing was performed on an FLC device manufactured in exactly the same manner as in Example 1.

[0058]

[Outside 11] The C1 orientation of the Sm ^* C phase was maintained over the entire temperature range, and uniform state switching by an electric field was possible.
At this time, the tilt angle theta _a apparent was 11.5 °.

Next, the cell orientation is aligned with the average molecular axes 81 and 82 as shown in FIG. 8 and the waveform shown in FIG. 9 (Vop = 25 V,
Δt = 25 μs) for about 7 hours, and then 83-8 in FIG.
When the cell thickness in the area of No. 6 was measured, the deviation from the initial cell thickness was as shown in Table 5.

[0060]

[Table 5]

When the cell was sandwiched between crossed Nicols polarizing plates and coloration was confirmed by silent observation, the region where the cell thickness was increased or decreased could not be recognized.

As a result of the X-ray analysis, Table 1 shows the layer tilt angle δ, the peak half width, and the layer structure diffraction peak area. this is,
An 80 μm-thick glass substrate was subjected to the same treatment as described above, and was obtained by the method described above. The cell thickness of this sample was 1.5 μm. The diffraction peak area and half width of this layer structure were 80% and 1.23 times that of Comparative Example 3, respectively.

(Comparative Example 1) An FLC element prepared in exactly the same manner as in Example 1 was used at a temperature of 100 ° C to -4 ° C / min. After cooling at a speed of 30 ° C. to 30 ° C., the same measurement and evaluation as in the example were performed without any other treatment. The C1 orientation of the Sm ^* C phase was maintained over the entire temperature range, and uniform state switching by an electric field was possible. At this time, the tilt angle theta _a apparent was 11.5 °.

Next, the cell orientation is aligned with the average molecular axes 81 and 82 as shown in FIG. 8 and the waveform shown in FIG. 9 (Vop = 25 V,
Δt = 25 μs) for about 7 hours, and then 83-8 in FIG.
When the cell thickness in the area of No. 6 was measured, the deviation from the initial cell thickness was as shown in Table 6.

[0065]

[Table 6]

When this cell was sandwiched between crossed Nicols polarizing plates and the coloration was confirmed by silent observation, when the marginal display was performed due to a remarkable change in cell thickness, the portions 83 and 85 turned yellow.

As a result of the X-ray analysis, Table 1 shows the layer tilt angle δ, the peak half width, and the layer structure diffraction peak area. this is,
An 80 μm-thick glass substrate was subjected to the same treatment as described above, and was obtained by the method described above. The cell thickness of this sample was 1.5 μm. The layer structure diffraction peak area and half width were 53% and 1.53 times that of Comparative Example 3, respectively.

(Comparative Example 2) Except that the rubbing density was tripled in the rubbing treatment, F
An LC element was prepared, and 100 to -4 ° C / min. At 30 ° C. to observe the orientation state. The pretilt under these rubbing conditions was measured to be 9 °. When the Sm ^* C phase was 55 ° C. or lower, C2 orientation appeared, and uniform uniform state switching was not possible.

Comparative Example 3 A tantalum oxide thin film was formed on a glass substrate having a 7.5 cm × 7.5 cm transparent electrode by a sputtering method, and the following polyimide 1% NMP solution was applied thereon by a spinner. Then, it was baked at 270 ° C. for 1 hour. Next, Example 1 was applied to this substrate.
The same rubbing treatment is performed as described above, and the rubbing direction is twisted clockwise by 10 ° when viewed from above the cell from the same direction and parallel to another substrate subjected to the same treatment.
The cells were adhered while keeping the cell thickness of 5 μm to form cells.
The mixed liquid crystal containing phenylpyrimidine as a main component was injected into the cell whose pretilt angle was determined to be 1.5 ° by a crystal rotation method. Sm ^*
When the C phase was 63 ° C. or lower, the C2 orientation was uniform and the orientation was spray orientation.

[Outside 1]

As a result of the X-ray analysis, Table 1 shows the layer tilt angle δ, the peak half width, and the diffraction peak area of the layer structure. this is,
An 80 μm-thick glass substrate was subjected to the same treatment as described above, and was obtained by the method described above. The cell thickness of this sample was 1.5 μm.

Table 7 summarizes the results of X-ray measurement in Examples 1, 4, and 5 and Comparative Examples 1 and 3 with respect to δ, peak area, and FWHM.

[0072]

[Table 7]

[0073]

According to the present invention as described above, according to the present invention, Ca
An increase in cell thickness at the end of a liquid crystal element using a liquid crystal exhibiting an iral smectic phase can be reduced, and stable driving can be performed for a long time.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a liquid crystal element that can be used in the present invention.

FIG. 2 is a diagram for explaining movement of a liquid crystal.

FIG. 3 is a diagram for explaining C1 orientation and C2 orientation.

FIG. 4 is a diagram for explaining spray orientation and uniform orientation.

FIG. 5 is a diagram showing a change in a layer structure by X-ray analysis.

FIG. 6 is a photograph of a crystal structure showing the orientation of a ferroelectric liquid crystal when slowly cooled from an Iso phase.

FIG. 7 is a photograph of a crystal structure showing the orientation of a ferroelectric liquid crystal when the orientation treatment according to the present invention is performed.

FIG. 8 is a diagram showing a temperature change of a cone angle of a liquid crystal used in an example of the present invention.

FIG. 9 is a diagram for explaining the orientation of cells used in an example of the present invention.

FIG. 10 is a diagram showing driving waveforms used in the embodiment of the present invention.

[Explanation of symbols]

11a, 11b Substrate 12a, 12b Transparent electrode 13a, 13b Insulating film 14a, 14b Alignment control film 15 Ferroelectric liquid crystal 16 Spacer 17a, 17b Polarizer 20 Rubbing direction 21, 21 'Average molecular axis 22 Liquid crystal moving direction 23 Cell Thickened region 31 Smectic layer 32 C1 oriented region 33 C2 oriented region 34 Lightning defect 35 Hairpin defect 51, 52 Splay orientation (Sm ^* C1) 53, 54 Uniform orientation (Sm ^* C1) 55, 56 Splay orientation (Sm) ^* C2)

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Nao Mori 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Akira Tsuboyama 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (56) References JP-A-2-176723 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G02F 1/3337 510

Claims (9)

(57) [Claims] 1. An alignment treatment method for a liquid crystal, wherein a liquid crystal exhibiting a chiral smectic phase is held between and opposed to each other, and an electrode for applying a voltage to the liquid crystal is formed on each of the facing surfaces. In a liquid crystal device including a pair of substrates processed to align the liquid crystal, an alternating current is applied to the liquid crystal, and the temperature of the device is raised and lowered during the period of the application of the alternating current. 2. The method according to claim 1, wherein both of the pair of substrates are subjected to a uniaxial alignment process in substantially the same direction. 3. The liquid crystal exhibiting the chiral smectic phase exhibits at least two stable states, and θa, which is の of the angle formed by the optical axes thereof, and the cone angle 該 of the liquid crystal are expressed as: Θ>θa> Θ 2. The method according to claim 1, wherein the method has a relationship of / 2. 4. In the orientation state of the liquid crystal exhibiting the chiral smectic phase, the relationship among the pretilt angle α, the inclination angle δ of the chiral smectic phase layer, and the cone angle is Θ−δ <α.
2. The method according to claim 1, wherein: 5. The method according to claim 1, wherein the step of raising and lowering the temperature of the element is raising and lowering the temperature within a smectic phase temperature. 6. A process for elevating the temperature of the element, and a smectic A phase, liquid crystal alignment treatment method according to claim 1, wherein the cause elevation temperature of between chiral smectic phase. 7. A uniaxial orientation treatment in substantially the same direction is performed on both of the pair of substrates, and axes of the treatment intersect each other at an intersection angle θc (20 °>θc> 0 °). 2. The method for aligning liquid crystals according to claim 1, wherein: 8. A method for manufacturing a liquid crystal element, comprising: holding a liquid crystal exhibiting a chiral smectic phase therebetween so as to oppose each other; and forming electrodes on each of the opposing surfaces for applying a voltage to the liquid crystal. A method for manufacturing a liquid crystal element, comprising: a step of raising and lowering the temperature of the element within a temperature range of a smectic phase in a liquid crystal element including a pair of substrates treated to align the liquid crystal. 9. A process for elevating the temperature of the element, and a smectic A phase, a method of manufacturing a liquid crystal device according to claim 8, wherein the allowed elevating temperature of between chiral smectic phase.