JP3109954B2 - Liquid crystal element and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal device used for a liquid crystal display device or a liquid crystal optical shutter, and more particularly to a liquid crystal device having improved gradation driving characteristics by improving hysteresis in the electro-optical response of liquid crystal. The present invention relates to the manufacturing method.

[0002]

2. Description of the Related Art A typical cell structure of a liquid crystal element holds a liquid crystal between two opposing electrodes, and controls the light transmittance of the cell by changing the direction of liquid crystal molecules by applying a voltage to the electrodes. Things.

[0003] In a cell using a twisted nematic (TN) liquid crystal, the transmittance can be changed in an analog manner according to the value of the applied voltage, so that gradation display can be performed.

On the other hand, there is a mirror dielectric liquid crystal as a liquid crystal material having excellent responsiveness and a wide viewing angle. A display device of the type that controls the amount of transmitted light by combining with a polarizer utilizing the refractive index anisotropy of ferroelectric liquid crystal molecules is Clark (Cl.
ark) and Lagerwall, JP-A-56-107216, U.S. Pat.
No. 67924, and the like. This ferroelectric liquid crystal generally shows a chiral smectic C phase (Sm ^* C phase) or H phase (Sm ^* H phase) having a non-helical structure in a specific temperature range. On the other hand, it has a property of taking one of the first optically stable state and the second optically stable state and maintaining that state even when the electric field is removed, that is, it has bistability. Furthermore, since ferroelectric liquid crystals have the characteristic of quick response to changes in the electric field, they are expected to be applied to large-screen, high-definition displays as high-speed drive storage media capable of simple matrix drive. I have.

As a method for performing gradation display using ferroelectric liquid crystal, a cell thickness gradient method, a potential gradient method, a method using a fine inversion region called a domain, and the like have been proposed. An element using a ferroelectric liquid crystal having this bistability has a voltage from a minimum transmittance (all black state) to a maximum transmittance (all white state) when a voltage for obtaining a specific halftone is applied. It is necessary to provide an appropriate threshold distribution in a predetermined range of the pulse width. In the case of such a gradation drive, a binary display technique of suppressing fluctuations using a drive margin as in binary display is not applied, and a specific write voltage (pulse width) is always applied to a specific write voltage (pulse width). Halftones must be obtained.

[0006]

However, if there is a hysteresis in the applied voltage-transmittance characteristic of the liquid crystal cell, it is impossible to perform a good gradation display. That is, in the case of going from the dark (black) state to the light (white) state and vice versa, even if a voltage having the same waveform is applied, the transmittances are different from each other.

US Pat. No. 4,712,877, assigned to the same assignee as the present application,
USP 4,747,671, USP 4,763,99
No. 4, US Pat. No. 4,796,980.

[0008] As a technique relating to the alignment and the material of the liquid crystal, US Pat. No. 4,639, assigned to the same assignee as the present application.
089, USP 4,681,404, USP 4,7
21, 365.

[0009]

An object of the present invention is to provide a liquid crystal element capable of suppressing occurrence of hysteresis and performing high-quality display with good reproducibility and a method of manufacturing the same. .

[0010]

A liquid crystal device for solving the above technical problems and achieving the object of the present invention relates to a liquid crystal device having a liquid crystal and an alignment layer for aligning the liquid crystal. adsorb neutral molecules and / or ionic molecules to the interface formed between the alignment layer and the
The interface is electrically neutral in the absence of liquid crystal .

The above-mentioned method of manufacturing a liquid crystal element is a method of manufacturing a liquid crystal element having a liquid crystal and an alignment layer for aligning the liquid crystal, wherein the alignment layer is formed on a surface of a substrate, and then the alignment layer is formed. In this method, neutral molecules and / or ionic molecules are adsorbed on the surface of the substrate, and then the liquid crystal is injected.

[0012]

According to the present invention, neutral molecules and / or ionic molecules are adsorbed in the vicinity of the interface between the liquid crystal having many trap levels and the alignment film, thereby forming the interface in the absence of the liquid crystal.
It can be electrically neutral and can fill the trap level. As a result, the formation of an asymmetric interface electric field can be prevented and the occurrence of hysteresis can be suppressed, and a display with excellent reproducibility can be performed without deterioration in display quality even when driving is continued for a long time.

[0013]

【Example】

(Description of the Preferred Embodiment) FIG. 1 schematically shows a cell cross-sectional structure of a liquid crystal element according to an embodiment of the present invention.

In FIG. 1, an electrode 1 and an alignment layer 3 are provided on a pair of substrates 2 respectively, and a liquid crystal material 4 is injected between the substrates 2 arranged so that the alignment layer 3 faces each other. .

At the interface between the alignment layer 3 and the liquid crystal material 4, an adsorption layer 5 for neutral molecules and / or ionic molecules is formed.

The constituent molecules of the adsorbing layer 5 are neutral monomolecules or neutral compound molecules such as water, alcohol, or the like, or ionic molecules formed by ionizing them, and the constituent atoms are oxygen, hydrogen, and carbon. It contains at least one atom selected from the group.

As the orientation layer 3, organic compounds or inorganic compounds such as polyaniline, polyamide, polyvinyl alcohol, polyimide, metal oxide, metal silicide, and silicon oxide are preferably used.

Further, as the pair of substrates 2, at least one of them is a translucent substrate. Examples of the light-transmitting substrate include glass, quartz, and resin, and examples of the light-impermeable substrate include metal, a silicon wafer, and a colored resin.

As the electrode 1, a transparent conductor such as tin oxide or indium oxide is preferably used, but a metal such as Cr, Al, Ta or the like may be used if light transmission is not required.

As the liquid crystal material 4, a nematic liquid crystal or a ferroelectric liquid crystal is preferably used.

Hereinafter, the effect of the adsorption layer used in the present invention will be described in detail.

First, the present inventors confirmed the existence of trap levels in the liquid crystal cell and the behavior of ions in the cell, and found that hysteresis was caused by these.

For easy understanding, when a ferroelectric liquid crystal is used as the liquid crystal, in the switching process of the ferroelectric liquid crystal, the dielectric relaxation process of the element immediately after application of an external electric field, the inversion process of the spontaneous electrode Ps, Various time domains such as the displacement process of impurity ions in the dielectric liquid crystal or alignment film, the dielectric relaxation process of the device after the external electric field is turned off, the stabilization (latch) process of the inverted spontaneous polarization Ps, and the relaxation process of impurity ions. Relaxation phenomena interfere with each other to form a complex time constant system. In addition, an IT for applying an electric field to the ferroelectric liquid crystal is used.
An interface between an electrode such as O and an alignment film such as rubbed polyimide as an alignment layer for aligning the liquid crystal;
In addition, at the interface between the alignment film and the ferroelectric liquid crystal layer, there are barriers and trap levels for charges such as electrons and ions. As a result, the electro-optical characteristics of the ferroelectric liquid crystal device are subject to improvements such as a reversal electric field caused by spontaneous polarization Ps, a threshold change caused by a state left unattended, and an optical response instability. I have it.

Among the various factors exhibiting these complicated behaviors, the factors related to the hysteresis are the anti-electric field caused by the spontaneous polarization of the liquid crystal itself and the insulating film of the alignment film. Behavior of impurity ions contained therein. The anti-electric field is a phenomenon that appears inevitably when the dielectric has a layered structure. The smaller the dielectric constant of the material used for the alignment film sandwiching the liquid crystal, the larger the anti-electric field is generated in the liquid crystal, and the electric field in the liquid crystal is reduced. Substantially lower. Further, as the thickness of the material increases, the influence of the anti-electric field is observed more. Until now, it is considered that the cause of the hysteresis is that the electric field accompanying the spontaneous polarization is canceled by moving to the interface so that the above-mentioned ions cancel out, and the electric field of 2Ps acts in the opposite direction to the next write voltage. I have been.

However, as a result of numerous experiments and studies by the present inventors, the actually observed hysteresis is larger than the value due to the expected 2Ps, and even if the thickness of the alignment film is extrapolated to zero. It was found that there was hysteresis. One reason that this hysteresis remains even if the thickness of the alignment film is assumed to be zero is that a layer where the liquid crystal does not move exists on the interface side in contact with the alignment film inside the liquid crystal. It is considered that this layer causes a counter-electric field similar to that of the alignment film due to the existence of the characteristic. In this case, the thickness of the layer in which the liquid crystal does not move is estimated to be several tens of nanometers according to calculations by the present inventors. Another factor is that ions are adsorbed at the interface, so that asymmetric space charges are formed at the two interfaces and an electric field like a DC bias is formed. The formation of this asymmetric space charge has been confirmed by the present inventors' experiments, and seems to be important for understanding the behavior of ions. This situation will be described in detail with reference to the drawings.

FIG. 2 shows a reversal current due to spontaneous polarization when a continuous rectangle having a voltage of 10 V and a frequency of 1 Hz is applied to a ferroelectric liquid crystal cell using a polyimide alignment film.
It shows a small electric displacement current appearing in a time on the order of c. These currents generally have spontaneous polarization (tens of n
(C / cm ² or less) is commonly observed in ferroelectric liquid crystals having a relatively small value (below C / cm ² ) because impurity ions contained in the ferroelectric move from one end in the liquid crystal to the other electrode. Are detected as time derivatives of electric displacement (electric flux density). From this current characteristic (reference numeral I ₁₎ absorption current is observed due to the dielectric body decreases general exponential until begins motion ions, followed by an increase in the number of ions for some Mechanism (code I ₂ reference ), The generated ions stay at the end after reaching one end, and are observed with one peak pp so that the electric displacement current gradually decreases. If the ions exist indefinitely or are generated indefinitely by a chemical reaction, this electric displacement current should have no single peak and exhibit a monotonically increasing or constant value. From this, assuming that the ions in the liquid crystal are of finite quantity, the mechanism of generation is that ions trapped at a level similar to the defect on the surface of the semiconductor or at the junction interface acquire energy from the electric field and are bound. It can be assumed that it is caused by being released from. Similarly to this generation mechanism, ions moved by the electric field arrive at one end and are trapped at the above-mentioned level at a rate higher than the generation rate, and the ions are considered to be deposited there.

As a field for the generation and trapping of such ions, the interface between the liquid crystal and the alignment film, in which the charge of spontaneous polarization appears as a bound charge, is a field for the generation and extinction of the largest amount of ions, and is a junction point of different alignment. A region near the chevron structure, a particularly disturbed region of the rubbing groove formed on the alignment film, and an uneven portion of a film such as ITO formed on the substrate are conceivable.

The formation of the space charge by the ion trap phenomenon can be examined by plotting the reciprocal of the time indicating the peak position of the current waveform related to the mobility of ions with the applied voltage. When this method is used, the reciprocal of the peak time at each voltage is on a single straight line, and the slope of this straight line indicates the mobility of the moving ion. The intercept of the voltage axis is the spatial electric field formed in the liquid crystal element. Is shown. The spatial electric field obtained by this method changes depending on the temperature.
To + 2V.

As described above, there is a difference between the ion generation rate and the ion trap rate, and the above-mentioned generation rate and trap rate have electric field dependence, respectively. A difference occurs in the amount of ions deposited on the existing ferroelectric liquid crystal-alignment film interface, and a DC bias is apparently applied to the liquid crystal.

Therefore, as a method of reducing a non-uniform spatial electric field due to ions being trapped at the interface, it is important to reduce the discontinuity at the trap interface, which is the cause. For example, it is conceivable to use an amorphous material for ITO to planarize ITO, or to use optical alignment without using mechanical rubbing as a means for orienting turbulence in the rubbing groove. . However, in this method, traps can be slightly reduced, but cannot be sufficiently removed so as not to cause hysteresis. Therefore, the present inventors adsorb ionic or neutral molecules that do not affect the properties of the liquid crystal even if they are mixed in the liquid crystal in advance at the interface between the alignment layer and the liquid crystal layer that can serve as a trap region, and trap By filling the level in advance with a substance different from the impurity ions in the liquid crystal, it was possible to prevent the impurity ions in the liquid crystal from being trapped when reaching the interface and forming an asymmetric interface electric field.

Normally, when the above method is not used, when the device is driven after the liquid crystal is mixed, the ions trapped in the shallow trap level can cross the trap level at a certain depth by the energy of the electric field. It behaves as mobile ions (generation of ions), and only ions having only positive or negative charges are trapped at the liquid crystal-alignment film interface at both interfaces after the movement process by the electric field.

The reason why the space charge is formed by the trap phenomenon is as follows: the difference between the generation rate of the positive or negative ions from the shallow trap level and the trap rate to the shallow trap level, the electric field intensity dependence of both rates, or the temperature dependence. Is mentioned. If there is a trap level deep enough not to easily emit (generate) ions in the electric field, the local distribution of ions at both interfaces reflecting the temperature distribution during liquid crystal injection, and the formation of an internal electric field due to the initial drive bias It is conceivable that only positive or negative ion species are trapped at both interfaces in both interfaces.

However, if the formation of the adsorption layer is used before injecting the liquid crystal, the electric field does not exist on the alignment film, and ions or neutral molecules added from the outside so as to maintain neutrality on the alignment film which can be a trap interface are maintained. Trap (adsorption) is performed in order from a deep trap level to a shallow trap level. Due to this electrical neutral condition, no space charge is formed even after liquid crystal injection because charges are not biased positively or negatively at both interfaces. In addition, since trap levels are buried in advance, even if impurity ions are unevenly distributed in the liquid crystal due to driving, these ions are not trapped or the trap rate is extremely slow, so that space charges cannot be formed.

FIG. 3 shows the behavior of impurity ions in the liquid crystal measured under the same conditions as in FIG. 2 when a trap level is generated by the method according to the present invention. As is apparent from this figure, an increase in current accompanying the generation of ions observed after measurement of the absorption current is not observed. This shows the behavior of the displacement current due to the fact that the ions remain at the counter electrode side without being trapped after moving to the counter electrode, and thereafter the opposite voltage is applied and the ions return from the counter electrode.

Next, an embodiment of a preferred production method of the present invention will be described.

First, an electrode and an alignment film are formed on a substrate. Next, if necessary, spacers and bonding beads are dispersed on the alignment film of one substrate, and then the two substrates are bonded. At this time, an adhesive for sealing is provided around the display area of the substrate excluding the injection port. Thus, an “empty cell” in which no liquid crystal is provided is prepared. Then, before injecting the liquid crystal material into the empty cells, at least one of neutral molecules or ionic molecules such as water molecules is adsorbed inside the empty cells.

As the adsorption method, it is preferable that the gas containing the above-described molecules is introduced into the empty cell after the empty cell is degassed by, for example, heating and depressurizing.

More specifically, a method in which a liquid as a raw material (source) of adsorbed molecules is placed in a container in a chamber together with an empty cell, and both are heated at a relatively low temperature in the chamber. .

As described above, it is effective to have an independent adsorption process.

In this case, a temperature range sufficient for adsorbing molecules is used.

More preferably, unnecessary molecules are eliminated,
In order to adsorb only necessary molecules as much as possible, the pressure in the chamber is reduced from the atmospheric pressure and the heat treatment is performed at a temperature near the boiling point of the source.

After the necessary molecules are thus adsorbed, the liquid crystal material is injected into the empty cell from the injection port.

In the injection step, first, the liquid crystal material is heated to be an isotropic phase (Iso phase) or a cholesteric phase (Ch phase).
The substance held in the phase) is injected under reduced pressure into the empty cell from the injection port.

Thereafter, the temperature of the empty cell is partially and gradually lowered, and the cell is transformed into a smectic phase (Sm phase).

However, the above-described injection step is an effective method for obtaining a smectic liquid crystal element.

As the liquid crystal material used in the present invention, U
SP 4,681,404, USP 4,714,323
No., USP 4,798,680, USP 4,844,
No. 597 can be used.

In particular, the present invention provides a liquid crystal having a so-called bookshelf orientation in which the rubbing treatment is performed on at least one of the substrates to reduce the pretilt angle of the obtained liquid crystal element to 5 ° or less and the smectic layer is not refracted. This is particularly effective for a liquid crystal element having a so-called chevron orientation as shown in FIG. 1 in which the element or the pretilt angle is 10 ° or more and the smectic layer is refracted.

The representative liquid crystal of the former is a fluorine-based liquid crystal material, and the representative of the latter is phenylpyrimidine (Pheny).
(pyrimidine) skeleton liquid crystal and a mixed liquid crystal containing the same as a main component, and the phase transition series thereof are as follows.

[0049]

[Outside 1]

In the former case, the upper and lower substrates are rubbed in opposite directions, and in the latter case, they are rubbed in substantially the same direction.

The mechanism has been described in detail with reference to a liquid crystal element using a ferroelectric liquid crystal as an example. However, as will be described again, the technical idea of the adsorption layer of the present invention is limited to the ferroelectric liquid crystal. However, the present invention can be applied to a liquid crystal element using various liquid crystal materials and an alignment layer for aligning the liquid crystal.

(Embodiment 1) Next, an embodiment of the present invention will be specifically described.

The embodiment is a cell having the same configuration as the cross-sectional view shown in FIG. First, a method for manufacturing this cell will be described.

After washing a glass substrate 2 having a thickness of about 1 mm and having a transparent electrode 1 on its surface, a polyimide alignment film 3 is applied by a spinner and baked at about 300 ° C. for about 1 hour to obtain about 100 A
It was formed in thickness. Next, rubbing was performed on the alignment film so that the upper and lower substrates were in the same direction, and appropriate fine irregularities were formed on the surface. Using this glass substrate, the phenylpyrimidine skeleton ferroelectric liquid crystal (spontaneous polarization: 7 nC / cm ² ) to be injected later was attached to both substrates at a sufficient interval so as to have a chevron structure to form an empty cell. The empty cell is degassed, and then the empty cell and a beaker containing an appropriate amount of water are placed in the same oven and heated at about 100 ° C. for 15 minutes to adsorb water molecules on the alignment film 3 in the cell. An adsorption layer 5 was formed. Next, the liquid crystal was injected into the cell while maintaining the liquid crystal material at a temperature at which the liquid crystal phase became an isotropic liquid layer. Thereafter, the mixture was gradually cooled to develop a chiral smectic C phase.

Thus, a chevron alignment having a pretilt angle of 10 ° or more was obtained.

<Measurement of Hysteresis> A drive pulse of a variable voltage is applied to the electrodes of the cell manufactured according to this embodiment, and the transmittance is measured. At this time, the transmittance is 50 from the applied voltage / transmittance characteristic (VT characteristic) in the direction from the all dark (all black) state to the all bright (all white) state and the VT characteristic in the opposite direction. %, And a difference between them is regarded as a physical quantity of hysteresis.

FIGS. 4A and 4B show pulse signals used in the measurement of the VT characteristic. FIG. 4A shows a drive pulse of a variable voltage for exhibiting a predetermined transmittance, and FIG. White)
A first reset pulse to be in a state,
(C) is a second reset pulse for setting the initial state to a completely dark (all white) state.

First, after repeatedly applying the first reset pulse (b) of FIG. 4 for 5 seconds to the cell electrode so as to be in a completely black state, a drive pulse (a) having a predetermined voltage value Vd is applied. The transmittance at that time was determined. Similarly, drive pulses set so that the voltage value Vd gradually increases were applied, and the transmittance was measured in the range of 0% to 100%. The result is shown as a curve C1 in FIG.

Next, the second reset pulse (c) shown in FIG. 4 is repeatedly applied for 5 seconds so that the cell electrode is completely white, and then the drive pulse (a) is applied to determine the transmittance at that time. Was. Similarly, drive pulses set so that the voltage value Vd is gradually reduced are respectively applied to the drive pulses from 100% to 0%.
Was measured.

The difference h between the voltage values of the two curves C1 and C2 at a transmittance of 50% obtained in this way, that is, the hysteresis was a small value of 0.2V.

(Comparative Example 1) Except for the adsorption layer 5, Example 1
A cell having the same configuration as that described above was produced, and the hysteresis was determined as described above. As a result, h became a large value of 0.6V.

<Dependence of Hysteresis on Orientation Film Thickness> The dependency of hysteresis on orientation film thickness was measured using the cell of Example 1 and the comparative cell obtained by a well-known manufacturing method.

FIG. 6 shows the result. As is clear from FIG. 6, the hysteresis value of this embodiment is smaller than that of this embodiment at the same film thickness, and it is found that the hysteresis is reduced by using this embodiment. Furthermore, in the ordinary method, when the film thickness of the alignment layer is extrapolated to zero, there is a finite hysteresis (which is considered to be caused by space charge). In this embodiment, the hysteresis is determined by the alignment film thickness. It is simply shown that the hysteresis is determined only by the anti-electric field depending on the thickness of the alignment layer. From this, it was found that in this embodiment, the formation of space charges in the cell was prevented.

Example 2 Next, a liquid crystal device according to Example 2 of the present invention will be described.

In this embodiment, a liquid crystal cell using an active matrix substrate having a thin film transistor in the liquid crystal cell was prepared. The method of manufacturing the orientation layer and the adsorption layer used for this is the same as the method described in the first embodiment. The difference is that a twisted nematic (TN type) is used as the liquid crystal. Using this cell, the volume resistance of the liquid crystal inside was determined to be 5 ×
It was 10 ¹⁰ (Ω / cm). This value was not clearly changed as compared with the case where the usual injection method was used. However, when the impedance of this cell was measured in the range of 5 Hz to 10 MHz, the impedance of the element in which the liquid crystal was injected by the usual method was as shown in FIG. 7 as if three elements connected in RC parallel were connected in series. As shown in FIG. 8, the impedance of the liquid crystal having the interface according to the present example was measured as if two parallel-connected RC capacitors were connected in series. That is, it has been confirmed that the configuration according to the present example removes an unidentified layer structure, resulting in a liquid crystal element simply including only two layers, a liquid crystal layer and an alignment layer.

FIG. 9 is a block diagram showing a color liquid crystal display device 114 using the liquid crystal element 104 according to the present invention for the display section 107.

This device 114 further receives the composite signal 108 and outputs the three primary color signals 11 of red (R), green (G) and blue (B).
1 and a liquid crystal element 1
A drive control circuit 102 for driving the drive circuit 04 and a timing signal generation circuit 103 for generating each timing signal are provided.

The three primary color signals 111 are the signals 11 for driving the liquid crystal.
2 to drive the liquid crystal element 104 and include the above-described gradation signal as shown in FIG.
Reference numeral 105 denotes an information signal including a gradation signal,
7 is a circuit for applying a vertical line, and 106 is a circuit for selecting a horizontal line of the matrix electrode 117. Also, 119
Is a video signal source such as a host computer or an image sensor.

According to the present invention, the hysteresis of the VT characteristic of the cell located at the intersection of the matrix is suppressed, so that good gradation display can be performed.

[0070]

As described above, in the present invention, ions or neutral molecules which do not affect the characteristics of the liquid crystal even if they are mixed in the liquid crystal at the interface between the alignment layer and the liquid crystal layer which can serve as trap regions. Pre-adsorbed, the presence of liquid crystal
When the interface is electrically neutralized and the trap level is filled in advance with a substance different from the impurity ions in the liquid crystal, the impurity ions in the liquid crystal are trapped when they reach the interface, resulting in an asymmetric interface. An electric field was prevented from being formed. As a result, a liquid crystal element capable of displaying a good gradation by reducing the hysteresis observed in the VT characteristic due to the formation of space charges has become possible.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a sectional configuration of a cell of a liquid crystal element according to an embodiment of the present invention.

FIG. 2 is a diagram showing an ionic current in a cell in a liquid crystal element having a conventional configuration.

FIG. 3 is a diagram showing an ionic current in a cell in a liquid crystal device according to the present invention.

FIG. 4 is a diagram showing a waveform of an applied pulse used for measuring hysteresis.

FIG. 5 is a diagram showing hysteresis.

FIG. 6 is a diagram showing the dependency of hysteresis on the thickness of an alignment layer.

FIG. 7 is a diagram showing a Cole-Cole plot of a liquid crystal element.

FIG. 8 is a diagram showing a Cole-Cole plot of a liquid crystal element according to Example 2 of the present invention.

FIG. 9 is a block diagram showing an example of a color liquid crystal display device using a liquid crystal element according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 electrode 2 substrate 3 alignment layer 4 liquid crystal material 5 adsorption layer

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-61-11724 (JP, A) JP-A-63-163426 (JP, A) JP-A-5-27241 (JP, A) JP-A-4- 267223 (JP, A) JP-A-4-232919 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/1337 G02F 1/13

Claims (10)

(57) [Claims] 1. A liquid crystal device having a liquid crystal and an alignment layer for aligning the liquid crystal, wherein a neutral molecule and / or an ionic molecule is adsorbed on an interface formed between the liquid crystal and the alignment layer. The interface in the absence of the liquid crystal
A liquid crystal element characterized by being electrically neutral . 2. The liquid crystal device according to claim 1, wherein the liquid crystal exhibits ferroelectricity. 3. The liquid crystal device according to claim 1, wherein the neutral molecules and / or ionic molecules are non-conductive or conductive. 4. The liquid crystal device according to claim 1, wherein the neutral molecules and / or ionic molecules are molecules composed of hydrogen, oxygen, and carbon atoms. 5. A method for manufacturing a liquid crystal device having a liquid crystal and an alignment layer for aligning the liquid crystal, wherein the alignment layer is formed on a surface of a substrate, and then neutral molecules and / or Alternatively , the liquid crystal is adsorbed by the
A method for manufacturing a liquid crystal element , wherein the interface is made electrically neutral in the absence of the liquid crystal , and then the liquid crystal is injected. 6. An apparatus having the liquid crystal element according to claim 1 as a display device. 7. The device according to claim 6, further comprising a driving circuit for applying a voltage to the liquid crystal. 8. The device according to claim 1, wherein the driving circuit drives the liquid crystal element according to a video signal from a signal source. 9. The liquid crystal device according to claim 1, wherein the liquid crystal is a smectic liquid crystal exhibiting a bookshelf orientation with a pretilt angle of 5 ° or less. 10. The liquid crystal device according to claim 1, wherein the liquid crystal is a smectic liquid crystal exhibiting a chevron alignment having a pretilt angle of 10 ° or more.